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+The Project Gutenberg EBook of Artistic Anatomy of Animals, by Édouard Cuyer
+
+This eBook is for the use of anyone anywhere at no cost and with
+almost no restrictions whatsoever.  You may copy it, give it away or
+re-use it under the terms of the Project Gutenberg License included
+with this eBook or online at www.gutenberg.org
+
+
+Title: Artistic Anatomy of Animals
+
+Author: Édouard Cuyer
+
+Release Date: December 15, 2011 [EBook #38315]
+
+Language: English
+
+Character set encoding: ISO-8859-1
+
+*** START OF THIS PROJECT GUTENBERG EBOOK ARTISTIC ANATOMY OF ANIMALS ***
+
+
+
+
+Produced by Chris Curnow, Harry Lamé and the Online
+Distributed Proofreading Team at https://www.pgdp.net (This
+file was produced from images generously made available
+by The Internet Archive)
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+
+  +--------------------------------------------------------------------+
+  |                       TRANSCRIBER'S NOTES                          |
+  |                                                                    |
+  | Transcription used in this e-text:                                 |
+  |   Texts in italics in the original work are transcribed between    |
+  |   underscores, as in _text_.                                       |
+  |   Bold-face text in the original work has been transcribed between |
+  |   equal signs, as in =text=.                                       |
+  |   Small capitals have been transcribed as ALL CAPITALS.            |
+  |   The author sometimes uses a different typeface to describe a     |
+  |   shape, as the V in V-form. Where this different typeface is used,|
+  |   this has been transcribed as [V].                                |
+  |                                                                    |
+  | More Transcriber's Notes will be found at the end of this text.    |
+  +--------------------------------------------------------------------+
+
+
+
+
+  THE
+  ARTISTIC ANATOMY OF ANIMALS
+
+
+
+
+  ARTISTIC
+  ANATOMY
+  OF ANIMALS
+
+  BY ÉDOUARD CUYER, SUPPLEMENTARY
+  PROF OF ANATOMY AT THE SCHOOL OF
+  FINE ART PARIS, PROF OF ANATOMY
+  AT THE SCHOOL OF FINE ART ROUEN
+
+  TRANSLATED & EDITED BY
+  GEORGE HAYWOOD
+  LECTURER ON ANATOMY AT THE ROYAL
+  COLLEGE OF ART SOUTH KENSINGTON
+
+  [Illustration]
+
+  LONDON
+  BAILLIÈRE, TINDALL & COX
+  8 HENRIETTA ST COVENT GARDEN
+
+  ANNO DOMINI
+  MDCCCCV
+
+  ALL RIGHTS
+  RESVD
+
+
+
+
+PREFACE
+
+
+A few lines will suffice to explain why we have compiled the present
+volume, to what wants it responds, and what its sphere of usefulness may
+possibly embrace.
+
+In our teaching of plastic anatomy, especially at the École des
+Beaux-Arts--where, for the past nine years, we have had the very great
+honour of supplementing the teaching of our distinguished master,
+Mathias Duval, after having been prosector for his course of lectures
+since 1881--it is our practice to give, as a complement to the study of
+human anatomy, a certain number of lessons on the anatomy of those
+animals which artists might be called on to represent.
+
+Now, we were given to understand that the subject treated in our
+lectures interested our hearers, so much so that we were not surprised
+to learn that a certain number repeatedly expressed a desire to see
+these lectures united in book form.
+
+To us this idea was not new; for many years the work in question had
+been in course of preparation, and we had collected materials for it,
+with the object of filling up a void of which the existence was to be
+regretted. But our many engagements prevented us from executing our
+project as early as we would have wished. It is this work which we
+publish to-day.
+
+[Illustration: FIG. I.--REPRODUCTION OF A SKETCH BY BARYE (COLLECTIONS
+OF THE ANATOMICAL MUSEUM OF THE ÉCOLE DES BEAUX-ARTS--HUGUIER MUSEUM).]
+
+Putting aside for a moment the wish expressed by our hearers, we feel
+ourselves in duty bound to inquire whether the utility of this
+publication is self-evident. Let it be clearly understood that we wish
+to express here our opinion on this subject, while putting aside every
+personal sentiment of an author.
+
+No one now disputes the value of anatomical studies made in view of
+carrying out the artistic representation of man. Nevertheless--for we
+must provide against all contingencies--the conviction on this subject
+may be more or less absolute; and yet it must possess this character in
+an intense degree in order that these studies may be profitable, and
+permit the attainment of the goal which is proposed in undertaking them.
+It is in this way that we ever strive to train the students whose
+studies we direct; not only to admit the value of these studies, but to
+be materially and deeply convinced of the fact without any restriction.
+Such is the sentiment which we endeavour to create and vigorously
+encourage. And we may be permitted to add that we have often been
+successful in this direction.
+
+Therefore it is that, at the beginning of our lectures, and in
+anticipation of possible objections, we are accustomed to take up the
+question of the utility of plastic anatomy. And in so doing, it is in
+order to combat at the outset the idea--as mischievous as it is
+false--which is sometimes imprudently enunciated, that the possession of
+scientific knowledge is likely to tarnish the purity and freshness of
+the impressions received by the artist, and to place shackles on the
+emotional sincerity of their representation.
+
+[Illustration: FIG. II.--REPRODUCTION OF A SKETCH OF BARYE (COLLECTIONS
+OF THE ANATOMICAL MUSEUM OF THE ÉCOLE DES BEAUX-ARTS--HUGUIER MUSEUM).]
+
+It is chiefly by employment of examples that we approach the subject.
+These strike the imagination of the student more forcibly, and the
+presentation of models of a certain choice, although rough in execution,
+is, in our opinion, preferable to considerations of an order possibly
+more exalted, but of a character less clearly practical. Let us, then,
+ask the question: Those artists whose eminence nobody would dare to
+question, did they study anatomy? If the answer be in the affirmative,
+we surely cannot permit ourselves to believe that we can dispense with a
+similar course. And, as proof of the studies of this class which the
+masters have made, we may cite Raphael, Michelangelo, and, above all,
+Leonardo da Vinci; and, of the moderns, Géricault. And we may more
+clearly define these proofs by an examination of the reproductions of
+their anatomical works, chosen from certain of their special
+writings.[1]
+
+  [1] Mathias Duval and A. Bical, 'L'anatomie des Maîtres.' Thirty
+      plates reproduced from the originals of Leonardo da Vinci,
+      Michelangelo, Raphael, Géricault, etc., with letterpress and a
+      history of plastic anatomy, Paris, 1890.
+
+      The manuscripts of Leonardo da Vinci of the Royal Library,
+      Windsor, 'Anatomy, Foliæ A.,' published by Théodore Sabachnikoff,
+      with a French translation, written and annotated by Giovanni
+      Piumati, with an introduction by Mathias Duval. Édouard Rouveyre,
+      publisher, Paris, 1898.
+
+      Mathias Duval and Édouard Cuyer, 'History of Plastic Anatomy: The
+      Masters, their Books, and Anatomical Figures' (Library of
+      Instruction of the School of Fine Arts), Paris, 1898.
+
+Accordingly, there is no scope for serious discussion, and it only
+remains for us to enunciate the opinion that it is necessary that we
+should imitate those masters, and, with a sense of respectful
+discipline, follow their example.
+
+Here, with regard to the anatomy of animals, we pursue the same method,
+and the example chosen shall be that of Barye. His talent is too far
+above all criticism to allow that this example should be refused. The
+admiration which the works of this great artist elicit is too
+wide-spread for us to remain uninfluenced by the lessons furnished by
+his studies. It is sufficient to see the sketches relating to these
+studies, and his admirable casts from nature which form part of the
+anatomical museum of the École des Beaux-Arts, to be convinced that the
+artistic temperament, of which Barye was one of the most brilliant
+examples, has nothing to lose by its association with researches the
+precision of which might seem likely to check its complete expansion.
+
+[Illustration: FIG. III.--REPRODUCTION OF A SKETCH OF BARYE (COLLECTIONS
+OF THE ANATOMICAL MUSEUM OF THE ÉCOLE DES BEAUX-ARTS--HUGUIER MUSEUM).]
+
+In those sketches we find proofs of observation so scrupulous that we
+cannot restrain our admiration for the man whose ardent imagination
+was voluntarily subjected to the toil of study so profound.
+
+If the example of Barye, with whom we associate the names of other great
+modern painters of animals, can determine the conviction which we seek
+to produce, we shall be sincerely glad. To contribute to the propagation
+of useful ideas, and to see them accepted, gives a feeling of
+satisfaction far too legitimate for us to hesitate to say what we should
+feel if our hope be realized in this instance.
+
+ÉDOUARD CUYER.
+
+[Illustration: FIG. IV.--REPRODUCTION OF A SKETCH OF BARYE (COLLECTIONS
+OF ANATOMICAL MUSEUM OF THE SCHOOL OF FINE ARTS--HUGUIER MUSEUM).]
+
+
+
+
+CONTENTS
+
+
+  INTRODUCTION
+
+                                                                   PAGE
+
+  GENERALITIES OF COMPARATIVE ANATOMY                                 1
+
+
+  CHAPTER I
+
+  OSTEOLOGY AND ARTHROLOGY:
+
+  THE TRUNK                                                           4
+  THE POSTERIOR LIMBS                                                78
+  THE POSTERIOR LIMBS IN SOME ANIMALS                                90
+  THE SKULL OF BIRDS                                                127
+
+
+  CHAPTER II
+
+  MYOLOGY:
+
+  THE MUSCLES OF THE TRUNK                                          131
+  MUSCLES OF THE ANTERIOR LIMBS                                     162
+  MUSCLES OF THE POSTERIOR LIMBS                                    200
+  MUSCLES OF THE HEAD                                               232
+
+
+  CHAPTER III
+
+  EPIDERMIC PRODUCTS OF THE EXTREMITIES OF THE FORE AND HIND LIMBS  247
+
+
+  CHAPTER IV
+
+  PROPORTIONS
+
+  PROPORTIONS OF THE HEAD OF THE HORSE                              273
+
+
+  CHAPTER V
+
+  THE PACES OF THE HORSE                                            282
+
+
+
+
+LIST OF ILLUSTRATIONS
+
+
+  FIG.                                                             PAGE
+
+    1. A HUMAN SKELETON IN THE ATTITUDE OF A QUADRUPED, TO GIVE A
+       GENERAL IDEA OF THE POSITION OF THE BONES IN OTHER
+       VERTEBRATES                                                    5
+    2. SIZE OF THE ATLAS COMPARED WITH THE TRANSVERSE DIMENSIONS OF
+       THE CORRESPONDING PARTS OF THE SKULL IN MAN                    7
+    3. SIZE OF THE ATLAS COMPARED WITH THE TRANSVERSE DIMENSIONS OF
+       THE CORRESPONDING REGIONS OF THE SKULL IN A DOG                8
+    4. LUMBAR VERTEBRÆ OF A QUADRUPED (THE HORSE): SUPERIOR SURFACE   9
+    5. A TRANSVERSE SECTION OF THE THORAX OF A MAN PLACED
+       VERTICALLY--THAT IS TO SAY, IN THE DIRECTION WHICH IT WOULD
+       ASSUME IN A MAN PLACED IN THE ATTITUDE OF A QUADRUPED (A
+       DIAGRAMMATIC FIGURE)                                          13
+    6. A VERTICAL SECTION OF THE THORAX OF A QUADRUPED
+       (DIAGRAMMATIC)                                                14
+    7. STERNUM OF A BIRD (THE COCK): LEFT SIDE, EXTERNAL SURFACE     17
+    8. ANTERIOR LIMB OF THE BAT: LEFT SIDE, ANTERIOR SURFACE         20
+    9. ANTERIOR LIMB OF THE SEAL: LEFT SIDE, EXTERNAL SURFACE        21
+   10. SITUATION AND DIRECTION OF THE SCAPULA IN THE HUMAN BEING,
+       THE TRUNK BEING HORIZONTAL, AS IN QUADRUPEDS. VERTICAL AND
+       TRANSVERSE SECTION OF THE THORAX (DIAGRAMMATIC FIGURE)        22
+   11. POSITION AND DIRECTION OF THE SCAPULA IN QUADRUPEDS.
+       VERTICAL AND TRANSVERSE SECTION OF THE THORAX (DIAGRAMMATIC
+       FIGURE)                                                       22
+   12. LEFT SCAPULA OF THE HUMAN BEING, POSTERIOR SURFACE, PLACED
+       IN THE POSITION WHICH IT WOULD OCCUPY IN THE SKELETON OF A
+       QUADRUPED                                                     23
+   13. LEFT SCAPULA OF A HORSE: EXTERNAL SURFACE                     23
+   14. VERTICAL AND TRANSVERSE SECTION, AT THE SITE OF THE
+       SHOULDERS, OF THE THORAX OF THE HORSE (DIAGRAMMATIC FIGURE)   24
+   15. VERTICAL AND TRANSVERSE SECTION, AT THE PLANE OF THE
+       SHOULDERS, OF THE THORAX OF THE DOG (DIAGRAMMATIC FIGURE)     24
+   16. LEFT CLAVICLE OF THE CAT: SUPERIOR SURFACE (NATURAL SIZE)     26
+   17. CLAVICLE OF THE DOG (NATURAL SIZE)                            26
+   18. SKELETON OF THE SHOULDER OF A BIRD (VULTURE): ANTERO-
+       EXTERNAL VIEW OF THE LEFT SIDE                                27
+   19. INFERIOR EXTREMITY OF THE LEFT HUMERUS OF A FELIDÆ (LION)     31
+   20. INFERIOR EXTREMITY OF THE LEFT HUMAN HUMERUS, SHOWING THE
+       PRESENCE OF A SUPRATROCHLEAR PROCESS                          31
+   21. SKELETON OF A BIRD (VULTURE): LEFT SURFACE                    33
+   22. THE HUMAN HAND RESTING FOR ITS WHOLE EXTENT ON ITS PALMAR
+       SURFACE: LEFT SIDE, EXTERNAL SURFACE                          35
+   23. THE HUMAN HAND RESTING ON ITS PHALANGES: LEFT SIDE, EXTERNAL
+       SURFACE                                                       36
+   24. THE HUMAN HAND RESTING ON THE TIPS OF SOME OF ITS THIRD
+       PHALANGES: LEFT SIDE, EXTERNAL VIEW                           36
+   25. SUPERIOR EXTREMITY OF THE BONES OF THE HUMAN FOREARM: LEFT
+       SIDE, SUPERIOR SURFACE                                        39
+   26. SUPERIOR EXTREMITY OF THE BONES OF THE FOREARM OF A DOG:
+       LEFT LIMB, SUPERIOR SURFACE                                   39
+   27. SUPERIOR EXTREMITY OF THE BONES OF THE FOREARM OF THE HORSE:
+       LEFT LIMB, SUPERIOR SURFACE                                   40
+   28. INFERIOR EXTREMITY OF THE BONES OF THE FOREARM OF A MAN:
+       LEFT SIDE, POSTERIOR SURFACE, POSITION OF SUPINATION          41
+   29. INFERIOR EXTREMITY OF THE BONES OF THE FOREARM OF A DOG:
+       LEFT SIDE, ANTERIOR SURFACE, NORMAL POSITION--THAT IS, THE
+       POSITION OF PRONATION                                         41
+   30. INFERIOR EXTREMITY OF THE BONE OF THE FOREARM OF THE HORSE:
+       LEFT SIDE, ANTERIOR SURFACE                                   42
+   31. SKELETON OF THE SUPERIOR LIMB OF A BIRD (VULTURE): LEFT
+       SIDE, EXTERNAL SURFACE                                        47
+   32. SUPERIOR LIMB OF THE HUMAN BEING, THE DIFFERENT SEGMENTS
+       BEING PLACED IN THE ATTITUDE WHICH THE CORRESPONDING PARTS
+       OCCUPY IN BIRDS: LEFT SIDE, EXTERNAL SURFACE                  48
+   33. SKELETON OF THE BEAR: LEFT LATERAL SURFACE                    50
+   34. SKELETON OF THE DOG: LEFT LATERAL SURFACE                     52
+   35. SCAPULA OF THE DOG: LEFT SIDE, EXTERNAL SURFACE               53
+   36. LEFT SCAPULA OF THE CAT: EXTERNAL SURFACE                     53
+   37. SKELETON OF THE FINGER OF A FELIDE (LION): LEFT SIDE,
+       INTERNAL SURFACE                                              57
+   38. SKELETON OF THE PIG: LEFT LATERAL SURFACE                     58
+   39. SKELETON OF THE OX: LEFT LATERAL SURFACE                      61
+   40. SKELETON OF THE HORSE: LEFT LATERAL SURFACE                   64
+   41. FLEXION OF THE HUMERUS: RIGHT ANTERIOR LIMB OF THE HORSE,
+       EXTERNAL SURFACE (AFTER A CHROMOPHOTOGRAPHIC STUDY BY
+       PROFESSOR MAREY)                                              74
+   42. EXTENSION OF THE HUMERUS: RIGHT ANTERIOR LIMB OF THE HORSE,
+       EXTERNAL SURFACE (AFTER A CHROMOPHOTOGRAPHIC STUDY BY
+       PROFESSOR MAREY)                                              74
+   43. THE LEFT ILIAC BONE OF THE HUMAN BEING: EXTERNAL SURFACE,
+       PLACED IN THE POSITION WHICH IT WOULD OCCUPY IN THE SKELETON
+       OF A QUADRUPED                                                79
+   44. LEFT ILIAC BONE OF A QUADRUPED (HORSE): EXTERNAL SURFACE      79
+   45. PUBIC REGION OF THE PELVIS OF A MARSUPIAL (PHALANGER, FOX)    81
+   46. PELVIS OF A BIRD (THE COCK): EXTERNAL SURFACE, LEFT SIDE      82
+   47. POSTERIOR LIMB OF THE HORSE PLACED IN THE POSITION WHICH IT
+       SHOULD OCCUPY IF THE ANIMAL WERE A PLANTIGRADE: LEFT LIMB,
+       EXTERNAL SURFACE                                              89
+   48. SKELETON OF THE FOOT OF A BIRD (THE COCK): LEFT SIDE,
+       EXTERNAL SURFACE                                              90
+   49. PELVIS OF THE DOG, SEEN FROM ABOVE                            91
+   50. PELVIS OF A FELIDE (LION), VIEWED FROM ABOVE                  92
+   51. PELVIS OF THE OX: SUPERIOR SURFACE                            95
+   52. TARSUS OF THE OX: POSTERIOR LEFT LIMB, ANTERO-EXTERNAL
+       SURFACE                                                       97
+   53. PELVIS OF THE HORSE: SUPERIOR SURFACE                        101
+   54. TARSUS OF THE HORSE: LEFT POSTERIOR LIMB, ANTERIOR SURFACE   104
+   55. EXTENSION OF THE LEG: RIGHT POSTERIOR LIMB OF THE HORSE,
+       EXTERNAL SURFACE (AFTER A CHRONOGRAPHIC STUDY BY PROFESSOR
+       MAREY)                                                       107
+   56. HUMAN SKULL: MEASURE OF THE FACIAL ANGLE BY THE METHOD OF
+       CAMPER. ANGLE BAC = 80°                                      110
+   57. SKULL OF THE HORSE: MEASURE OF THE FACIAL ANGLE BY THE
+       METHOD OF CAMPER. ANGLE BAC = 13°                            110
+   58. SKULL OF ONE OF THE FELIDÆ (JAGUAR): LEFT LATERAL ASPECT     113
+   59. SKULL OF THE LION: LEFT LATERAL ASPECT                       113
+   60. SKULL OF THE DOG: LEFT LATERAL ASPECT                        115
+   61. SKULL OF THE PIG: LEFT LATERAL ASPECT                        117
+   62. SKULL OF THE OX: LEFT LATERAL ASPECT                         119
+   63. SKULL OF THE HORSE: LEFT LATERAL ASPECT                      121
+   64. SKULL OF THE HARE: LEFT LATERAL ASPECT                       123
+   65. SKULL OF THE COCK: LEFT LATERAL SURFACE                      128
+   66. MYOLOGY OF THE HORSE: ANTERIOR ASPECT OF THE TRUNK           132
+   67. MYOLOGY OF THE HORSE: INFERIOR ASPECT OF THE TRUNK           135
+   68. MYOLOGY OF THE DOG: SUPERFICIAL LAYER OF MUSCLES             141
+   69. MYOLOGY OF THE OX: SUPERFICIAL LAYER OF MUSCLES              143
+   70. MYOLOGY OF THE HORSE: SUPERFICIAL LAYER OF MUSCLES           146
+   71. MYOLOGY OF THE HORSE: PANNICULUS MUSCLE OF THE TRUNK         148
+   72. MYOLOGY OF THE HORSE--SHOULDER AND ARM: LEFT SIDE, EXTERNAL
+       SURFACE                                                      166
+   73. MYOLOGY OF THE DOG: LEFT ANTERIOR LIMB, EXTERNAL ASPECT      178
+   74. MYOLOGY OF THE OX: LEFT ANTERIOR LIMB, EXTERNAL ASPECT       180
+   75. MYOLOGY OF THE HORSE: LEFT ANTERIOR LIMB, EXTERNAL ASPECT    182
+   76. MYOLOGY OF THE DOG: LEFT ANTERIOR LIMB, INTERNAL ASPECT      190
+   77. MYOLOGY OF THE HORSE: ANTERIOR LIMB, LEFT SIDE, INTERNAL
+       ASPECT                                                       192
+   78. LEFT ANTERIOR LIMB OF THE HORSE: INTERNAL ASPECT             194
+   79. LEFT ANTERIOR LIMB OF THE HORSE: EXTERNAL ASPECT             196
+   80. LEFT ANTERIOR LIMB OF THE HORSE: EXTERNAL ASPECT             196
+   81. DIAGRAM OF THE POSTERIOR PART OF A TRANSVERSE SECTION
+       PASSING THROUGH THE MIDDLE OF THE LEFT FORE-LIMB OF THE DOG:
+       SURFACE OF THE INFERIOR SEGMENT OF THE SECTION               198
+   82. DIAGRAM OF A HORIZONTAL SECTION OF THE MIDDLE OF THE FOREARM
+       OF THE LEFT LEG OF THE HORSE: SURFACE OF THE INTERIOR
+       SEGMENT OF THE SECTION                                       198
+   83. MYOLOGY OF THE HORSE: THE ANTERIOR TIBIAL MUSCLE (FLEXOR OF
+       THE METATARSUS), LEFT LEG, ANTERIOR VIEW                     214
+   84. MYOLOGY OF THE DOG: LEFT HIND-LIMB, EXTERNAL ASPECT          216
+   85. MYOLOGY OF THE OX: LEFT LEG, EXTERNAL ASPECT                 218
+   86. MYOLOGY OF THE HORSE: LEFT HIND-LIMB, EXTERNAL ASPECT        220
+   87. MYOLOGY OF THE DOG: LEFT HIND-LIMB, INTERNAL ASPECT          222
+   88. MYOLOGY OF THE HORSE: LEFT HIND-LEG, INTERNAL ASPECT         223
+   89. MYOLOGY OF THE DOG: MASTICATORY MUSCLES (A DEEPER DISSECTION
+       THAN THAT SHOWN IN FIG. 90)                                  233
+   90. MYOLOGY OF THE DOG: MUSCLES OF THE HEAD                      235
+   91. MYOLOGY OF THE OX: MUSCLES OF THE HEAD                       237
+   92. MYOLOGY OF THE HORSE: MUSCLES OF THE HEAD                    239
+   93. CLAW OF THE DOG: INFERIOR SURFACE                            249
+   94. LEFT HAND OF THE DOG: INFERIOR SURFACE, PLANTAR TUBERCLES    249
+   95. VERTICAL ANTERO-POSTERIOR SECTION OF THE FOOT OF A HORSE     250
+   96. THIRD PHALANX OF THE HORSE: LEFT ANTERIOR LIMB, EXTERNAL
+       SURFACE                                                      251
+   97. LEFT ANTERIOR FOOT OF THE HORSE: ANTERIOR ASPECT             253
+   98. LEFT ANTERIOR FOOT OF THE HORSE: EXTERNAL ASPECT             254
+   99. VERTICAL AND TRANSVERSE SECTION OF A LEFT HUMAN FOOT:
+       OUTLINE OF THE SURFACE OF THE POSTERIOR SEGMENT OF THIS
+       SECTION (DIAGRAMMATIC FIGURE)                                255
+  100. INFERIOR SURFACE OF A FORE-HOOF OF THE HORSE: LEFT SIDE      256
+  101. THIRD PHALANX OF THE HORSE: LEFT ANTERIOR LIMB, INFERIOR
+       VIEW                                                         257
+  102. THIRD PHALANX OF THE HORSE: LEFT POSTERIOR LIMB, INFERIOR
+       VIEW                                                         257
+  103. INFERIOR SURFACE OF A HIND-HOOF OF A HORSE: LEFT SIDE        258
+  104. LEFT POSTERIOR FOOT OF A HORSE: EXTERNAL ASPECT              259
+  105. FOOT OF THE OX: LEFT SIDE, ANTERO-EXTERNAL VIEW              260
+  106. THE PROPORTIONS OF THE HORSE (AFTER BOURGELAT)               265
+  107. PROPORTIONS OF THE HORSE (AFTER COLONEL DUHOUSSET)           270
+  108. PROPORTIONS OF THE HEAD OF THE HORSE, VIEWED IN PROFILE
+       (AFTER COLONEL DUHOUSSET)                                    274
+  109. THE SAME DESIGN AS THAT OF FIG. 108, ON WHICH WE HAVE
+       INDICATED, BY SIMILAR LINES, THE PRINCIPAL CORRESPONDING
+       MEASUREMENTS                                                 275
+  110. PROPORTIONS OF THE HEAD OF THE HORSE, SEEN FROM THE FRONT
+       (AFTER COLONEL DUHOUSSET)                                    276
+  111. THE SAME FIGURE AS FIG. 110, ON WHICH WE HAVE MARKED, BY
+       SIMILAR LINES, THE PRINCIPAL MEASUREMENTS WHICH CORRESPOND
+       THERETO                                                      277
+  112. HORSE OF WHICH THE LENGTH CONTAINS MORE THAN TWO AND A HALF
+       TIMES THAT OF THE HEAD, AND OF WHICH THIS DIMENSION (A, B)
+       EXCEEDS THE HEIGHT                                           279
+  113. HORSE OF WHICH THE LENGTH CONTAINS MORE THAN TWO AND A HALF
+       TIMES THAT OF THE HEAD, AND OF WHICH THIS DIMENSION (A, B)
+       EXCEEDS THE HEIGHT                                           280
+  114. HORSE OF WHICH THE LENGTH CONTAINS MORE THAN TWO AND A HALF
+       TIMES THAT OF THE HEAD, AND OF WHICH THIS DIMENSION (A, B)
+       IS INFERIOR TO THE HEIGHT                                    281
+  115. EXPERIMENTAL SHOES, INTENDED TO RECORD THE PRESSURE OF THE
+       FOOT ON THE GROUND                                           284
+  116. RUNNER FURNISHED WITH THE EXPLORATORY AND REGISTERING
+       APPARATUS OF THE VARIOUS PACES                               285
+  117. TRACING OF THE RUNNING OF A MAN (AFTER PROFESSOR MAREY)      286
+  118. NOTATION OF A TRACING OF THE RUNNING OF A MAN (AFTER
+       PROFESSOR MAREY)                                             287
+  119. NOTATION OF VARIOUS MODES OF PROGRESSION OF A MAN (AFTER
+       PROFESSOR MAREY)                                             287
+  120. SWING OF THE RAISED ANTERIOR LIMB (AFTER G. COLIN)           289
+  121. SWING OF THE ANTERIOR LIMB ON THE POINT OF PRESSURE (AFTER
+       G. COLIN)                                                    290
+  122. POSTERIOR LIMB, GIVING THE IMPULSE (AFTER G. COLIN)          291
+  123. NOTATION OF THE AMBLING GAIT IN THE HORSE (AFTER PROFESSOR
+       MAREY)                                                       292
+  124. THE AMBLE: RIGHT LATERAL PRESSURE                            293
+  125. NOTATION OF THE GAIT OF THE TROT IN A HORSE (AFTER PROFESSOR
+       MAREY)                                                       294
+  126. THE TROT: RIGHT DIAGONAL PRESSURE                            295
+  127. THE TROT: TIME OF SUSPENSION                                 295
+  128. NOTATION OF THE PACE OF STEPPING IN THE HORSE (AFTER
+       PROFESSOR MAREY)                                             296
+  129. THE STEP: RIGHT LATERAL PRESSURE                             297
+  130. THE STEP: RIGHT DIAGONAL PRESSURE                            297
+  131. THE GALLOP: FIRST PERIOD                                     298
+  132. THE GALLOP: SECOND PERIOD                                    298
+  133. THE GALLOP: THIRD PERIOD                                     299
+  134. THE GALLOP: TIME OF SUSPENSION                               299
+  135. NOTATION OF THE GALLOP DIVIDED INTO THREE PERIODS OF TIME
+       (AFTER PROFESSOR MAREY)                                      300
+  136. NOTATION OF THE GALLOP OF FOUR PERIODS IN THE HORSE (AFTER
+       PROFESSOR MAREY)                                             300
+  137. LEAP OF THE HARE (AFTER G. COLIN)                            301
+  138. THE LEAP                                                     302
+  139. THE LEAP                                                     302
+  140. THE LEAP                                                     303
+  141. THE LEAP                                                     303
+  142. THE LEAP                                                     305
+  143. THE LEAP                                                     305
+
+
+
+
+THE ARTISTIC ANATOMY OF ANIMALS
+
+
+
+
+INTRODUCTION
+
+GENERALITIES OF COMPARATIVE ANATOMY
+
+
+Of the animals by which we are surrounded, there are some which,
+occupying a place in our lives by reason of their natural endowments,
+are frequently represented in the works of artists--either as
+accompanying man in his work or in his amusements, or as intended to
+occupy the whole interest of the composition.
+
+The necessity of knowing, from an artistic point of view, the structure
+of the human body makes clear the importance we attach, from the same
+point of view, to the study of the anatomy of animals--that is, the
+study of comparative anatomy. The name employed to designate this branch
+of anatomy shows that the object of this science is the study of the
+relative position and form which each region presents in all organized
+beings, taking for comparison the corresponding regions in man. The head
+in animals compared with the human head; the trunk and limbs compared to
+the trunk and limbs of the human being--this is the analysis we
+undertake, and the plan of the subject we are about to commence.
+
+Our intention being, as we have just said, the comparison of the
+structure of animals with that of man, should we describe the anatomy of
+the human being in the pages which follow? We do not think so. Plastic
+human anatomy having been previously studied in special works,[2] we
+take it for granted that these have been studied before undertaking the
+subject of comparative anatomy. We will therefore not occupy time with
+the elementary facts relative to the skeleton and the superficial layer
+of muscles. We will not dilate on the division of the bones into long,
+short, large, single, paired, etc. All these preliminary elements we
+shall suppose to have been already studied.
+
+  [2] Mathias Duval, 'Précis of Anatomy for the Use of Artists': Paris,
+      1881. 'Artistic Anatomy of the Human Body,' third edition, plates
+      by Dr. Fau, text with figures by Édouard Cuyer: Paris, 1896.
+      'Artistic Anatomy of Man,' by J. C. L. Sparkes, second edition,
+      text with 50 plates: Baillière, Tindall and Cox, London, 1900.
+
+This being granted, it is, nevertheless, necessary to take a rapid
+bird's-eye view of organized beings, and to recall the terms used in
+their classification.
+
+Animals are primarily classed in great divisions, based on the general
+characters which differentiate them most. These divisions, or
+_branches_, allow of their being so grouped that in each of them we find
+united the individuals whose general structure is uniform; and under the
+name of vertebrates are included man and the animals with which our
+studies will be occupied. The vertebrates, as the name indicates, are
+recognised by the presence of an interior skeleton formed by a central
+axis, the vertebral column, round which the other parts of the skeleton
+are arranged.
+
+The vertebrate branch is divided into classes: fishes, amphibians or
+batrachians, reptiles, birds, and mammals.
+
+The mammals--from the Latin _mamma_, a breast--are characterized by the
+presence of breasts designed for the alimentation of their young. Their
+bodies are covered with hair, hence the name _pilifères_ proposed by
+Blainville; and, notwithstanding that in some individuals the hairs are
+few, the character is sufficient to distinguish them from all other
+vertebrates.
+
+We find united in this class animals which, at first, seem out of place,
+such as the whale and the bat; and, from their external appearance
+alone, the former would appear to belong to the fishes, and the latter
+to birds. Yet, on studying their structure, we find that, not only do
+these animals merit a place in the class which they occupy, because they
+possess the distinctive characters of mammals; but, still further, their
+internal structure is analogous to that of man and of the other
+individuals of this class.
+
+Notwithstanding this similarity of structure, the whale is not without
+some points of difference from its neighbours the horse and the dog;
+therefore, in order to place each of these animals in a position
+suitable to it, mammals are divided into secondary groups called
+_orders_. The first of these orders includes, under the name _primates_,
+man and apes. The latter contain animals which approach birds in certain
+characters of their organism, forming a link between the latter and
+mammals.
+
+We find, in studying the regions of the body in some of the vertebrates,
+that, while they present differences from the corresponding regions of
+the human body, they also offer most striking analogies. We can, for
+example, recognise the upper limb of man in the anterior one of
+quadrupeds, in the wing of the bat, in the paddle of the seal, etc. It
+is, so to speak, those variations of a great plan which give such a
+charm to the study of comparative anatomy.
+
+The division of classes into orders, which we have just mentioned,
+being still too general, it was found necessary to establish
+subdivisions--more and more specialized--to which the names _families_,
+_genera_, _species_, and _varieties_ were given.
+
+
+
+
+CHAPTER I
+
+OSTEOLOGY AND ARTHROLOGY
+
+
+THE TRUNK
+
+The Vertebral Column
+
+We commence the study of the skeleton with a description of the trunk.
+
+The trunk being, in quadrupeds, horizontal in direction (Fig. 1), the
+two regions of which it consists occupy, for this reason, the following
+positions: the thorax occupies the anterior part, the abdomen is placed
+behind it; the vertebral column is horizontal, and is situated at the
+superior aspect of the trunk; it projects beyond the latter: anteriorly,
+to articulate with the skull; and, posteriorly, to form the skeleton of
+the tail, or caudal appendix.
+
+The number of the vertebræ is not the same in all mammalia. Of the
+several regions of the vertebral column, the cervical shows the greatest
+uniformity in the number of the vertebræ of which it consists, with but
+two exceptions (eight or nine in the three-toed sloth, and six in the
+manatee); we always find seven cervical vertebræ, whatever the length of
+the neck of the animal. There are no more than seven vertebræ in the
+long neck of the giraffe, but they are very long ones; and not less than
+seven in the very short neck of the dolphin, in which they are reduced
+to mere plates of bone not thicker than sheets of cardboard. If the
+cervical region presents uniformity in the number of its bones, it is
+not so with the other regions of the column.
+
+The following table shows their classification in some animals:
+
+VERTEBRÆ.
+
+  +------------+-----------+---------+---------+
+  |            | Cervical. | Dorsal. | Lumbar. |
+  +------------+-----------+---------+---------+
+  | Bear       |    7      |    14   |    6    |
+  | Dog        |    7      |    13   |    7    |
+  | Cat        |    7      |    13   |    7    |
+  | Rabbit     |    7      |    12   |    7    |
+  | Pig        |    7      |    14   |  6 or 7 |
+  | Horse      |    7      |    18   |  6 or 5 |
+  | Ass        |    7      |    18   |    5    |
+  | Camel      |    7      |    12   |    7    |
+  | Giraffe    |    7      |    14   |    5    |
+  | Ox         |    7      |    13   |    6    |
+  | Sheep      |    7      |    13   |    6    |
+  +------------+-----------+---------+---------+
+
+[Illustration: FIG. 1.--A HUMAN SKELETON IN THE ATTITUDE OF A QUADRUPED.
+TO GIVE A GENERAL IDEA OF THE POSITION OF THE BONES IN OTHER
+VERTEBRATES.]
+
+It is worthy of notice that in birds the number of the cervical vertebræ
+is not constant, as in mammals; they are more numerous than the dorsal.
+These latter are almost always joined to one another by a fusion of
+their spinous processes; the two or three last vertebræ are similarly
+united to the iliac bones, between which they are fixed. The dorsal
+vertebræ thus form one piece, which gives solidity to the trunk, and
+provides a base of support to the wings, for the movements of flying.
+There are, so to speak, no lumbar vertebræ, the bones of that region,
+which cannot be differentiated from the sacrum, having coalesced with
+the bones of the pelvis.
+
+VERTEBRÆ.
+
+  +------------------+-----------+---------+
+  |                  | Cervical. | Dorsal. |
+  +------------------+-----------+---------+
+  | Vulture          |    15     |    7    |
+  | Eagle            |    13     |    9    |
+  | Cock             |    14     |    7    |
+  | Ostrich          |    18     |    9    |
+  | Swan             |    23     |   10    |
+  | Goose            |    18     |    9    |
+  | Duck             |    15     |    9    |
+  +------------------+-----------+---------+
+
+In reptiles, the relation between the number of the cervical vertebræ
+and that of the dorsal is very variable; some serpents are devoid of
+cervical vertebræ, having only dorsal ones--that is, vertebræ carrying
+well-developed ribs.
+
+VERTEBRÆ.
+
+  +-------------------+-----------+---------+---------+
+  |                   | Cervical. | Dorsal. | Lumbar. |
+  +-------------------+-----------+---------+---------+
+  | Crocodile         |    7      |    14   |    3    |
+  | Caiman            |    7      |    12   |    5    |
+  | Boa               |    3      |   248   |    0    |
+  | Python            |    0      |   320   |    0    |
+  | Viper             |    2      |   145   |    0    |
+  +-------------------+-----------+---------+---------+
+
+Regarding the direction of the vertebral column in animals, in which the
+trunk is not vertical, it is evident that the spinous processes point
+upward, and that in comparing them with those of man they must be
+arranged so that the superior surface of the human vertebra will
+correspond to the anterior surface of that of the quadruped. Of the
+cervical vertebræ, the atlas and axis call for special notice. Apropos
+of the atlas, we find that it, in the human being, is narrower than the
+corresponding parts of the skull, and is therefore hidden under the base
+of the cranium (Fig. 2); in quadrupeds its width is equal to that of the
+skull, and sometimes exceeds, because of the great development of its
+wing-shaped transverse processes, that of the neighbouring parts of the
+head (Fig. 3). On this account those transverse processes often project
+under the skin of the lateral surfaces of the upper part of the neck.
+
+[Illustration: FIG. 2.--SIZE OF THE ATLAS COMPARED WITH THE TRANSVERSE
+DIMENSIONS OF THE CORRESPONDING PARTS OF THE SKULL IN MAN.
+
+1, Atlas; 2, mastoid process; 3, external occipital protuberance; 4,
+inferior maxilla.]
+
+The axis is furnished on its anterior surface with the odontoid process,
+which articulates with the anterior (or inferior) arch of the atlas,
+according to the direction of the neck. The spinous process, flattened
+from without inwards, is more or less pointed; it is elongated from
+before backwards, so as partly to overlap the atlas and the third
+cervical vertebra.
+
+We find that this process overlaps less and less the neighbouring
+vertebræ when we examine in succession the bear, the cat, the dog, the
+ox, and the horse. With regard to the other vertebræ of this region,
+they diminish in width from the second to the seventh; and, in some
+animals, the anterior surface of the body presents a tubercle which
+articulates with a cavity hollowed in the posterior surface of that of
+the vertebra before it; this feature dwindles away in the dorsal and
+lumbar regions.
+
+The spinous process, slightly developed in the third cervical vertebra,
+gradually increases in size to the seventh, the spinous process of
+which, long and pointed, well deserves the name of _the prominent_ which
+is bestowed on it; but it should not be forgotten that the spinous
+process of the axis is equally developed.
+
+[Illustration: FIG. 3.--SIZE OF THE ATLAS COMPARED WITH THE TRANSVERSE
+DIMENSIONS OF THE CORRESPONDING REGIONS OF THE SKULL IN A DOG.
+
+1, Atlas; 2, zygomatic arch; 3, external occipital protuberance; 4,
+inferior maxilla.]
+
+On the inferior surface of the body of each of the vertebræ is found a
+prominent crest, especially well marked at the posterior part; this
+crest is but slightly developed in the bear and in the cat tribe, and is
+not found in swine.
+
+The transverse processes of the cervical vertebræ, from their relation
+to the trachea, are known as the _tracheal processes_.
+
+The most marked characteristic of the dorsal vertebræ is furnished by
+the spinous processes. They are long and narrow. As a rule, the spinous
+processes of the foremost dorsal vertebræ are the most developed and
+are directed obliquely upwards and backwards. As we approach the last
+vertebræ of this region, the processes become shorter and tend to become
+vertical, and the last ones are even, in some cases, directed upwards
+and forwards; this disposition is well marked in the dog and the cat. In
+the cetaceans, on the contrary, the length of the spinous processes
+increases from the first to the last.
+
+[Illustration: FIG. 4.--LUMBAR VERTEBRÆ OF A QUADRUPED (THE HORSE):
+SUPERIOR SURFACE.
+
+1, Spinous process; 2, anterior articular process and transverse process
+of the first lumbar vertebra of the left side; 3, costiform process.]
+
+In the horse the spinous processes of the first dorsal vertebræ produce
+the prominence at the anterior limit of the trunk, where the mane ends,
+which is known as the _withers_.
+
+The lumbar vertebræ are thicker than the preceding; they are known by
+their short and latterly-flattened spinous processes, and still more
+readily by their transverse processes, which, as they are evidently
+atrophied ribs, it is more accurate to denominate costiform processes
+(Fig. 4). These are long, flattened from above downwards, and directed
+outwards and forwards.
+
+The true transverse processes are represented by tubercles situated on
+the superior borders of the articular processes of each of the vertebræ
+of the lumbar region. Apropos of these different osseous processes, we
+are reminded that they are also present in the human skeleton.
+
+In the horse the costiform processes of the fifth and sixth lumbar
+vertebræ articulate, and are sometimes ankylosed, one with the other;
+the terminal ones articulate with the base of the sacrum. Sometimes the
+processes of the fourth and fifth are thus related; this is the case in
+the figure (4) given; here the costiform processes of the fourth and
+fifth vertebræ articulate, and the two terminal ones have coalesced.
+
+In the ox, the same processes are more developed than in the horse;
+their summits elevating the skin, produce, especially in animals which
+have not much flesh, prominences which limit the flanks in the superior
+aspect. The costiform processes of the last lumbar vertebræ are separate
+from each other; those of the latter are not in contact with the sacrum.
+
+=The Sacrum.=[3]--This bone, single and median, is formed by the mutual
+coalescence of several vertebræ, which vary in number according to the
+species observed.
+
+  [3] In human anatomy, the sacrum and the coccyx are studied as part of
+      the pelvis; we, therefore, in the study of the artistic anatomy of
+      man, study these bones with the bones of the lower limbs. Here we
+      do not follow this plan. In animals the sacrum and the coccyx, as
+      a matter of fact, clearly continue the superior border of the
+      skeleton of the trunk; hence we study them with the vertebral
+      column.
+
+_Vertebræ Constituting the Sacrum._--Bears, 5; dogs, 3; cats, 3;
+rabbits, 4; swine, 4; horses, 5; camels, 4; oxen, 5; sheep, 4.
+
+The sacrum is situated between the two iliac bones; with which it
+articulates, and contributes to the formation of the pelvis. It is
+obliquely placed, from before backwards, and from below upwards;
+immediately behind the lumbar section of the vertebral column; and is
+continued by the coccygeal vertebræ, which form the skeleton of the
+tail.
+
+It is triangular in outline, and is generally more narrow in proportion
+than in the human being. All things considered, it is more large and
+massive, and of greater density, in species which sometimes assume the
+upright posture, rather than in those which cannot assume that
+attitude; for example, the sacrum of the ape, of the bear, of the dog,
+and of the opossum are proportionately larger than those of the
+horse.[4]
+
+  [4] This is particularly striking only in those portions of the sacrum
+      that are not in relation with the other bones of the pelvis. We
+      think that the general form of this bone depends on the mode of
+      its connexions with the iliac bones and the extent of the
+      articular surfaces by which it is in contact with the latter.
+
+Its superior surface presents a crest, formed by the fusion of the
+spinous processes of the vertebræ which form it. In certain species
+these processes are attached only by their bases, and are separated from
+each other superiorly. In the pig they are wholly wanting.
+
+=The Coccygeal Vertebræ.=--These vertebræ, few in number (and sometimes
+ankylosed) in the human being, form in the latter a small series, the
+coccyx; which is inclined forwards, that is to say, towards the interior
+of the pelvis. In quadrupeds, on the contrary, their number is large;
+they are not ankylosed, and they form the skeleton of the caudal
+appendix.
+
+The first coccygeal vertebræ--that is, those which are next the
+sacrum--present characters which are common to those of other regions:
+they have a body, a foramen, and processes. As we trace them backwards,
+these characters become gradually effaced; and they become little more
+than small osseous cylinders simply expanded at their extremities.
+
+
+Direction and Form of the Spinal Column
+
+The curves of the vertebral column are, in quadrupeds, slightly
+different from those which characterize the human spine. First, instead
+of their being, as in the latter, curves in the antero-posterior aspect,
+because of the general attitude of the body, they are turned in the
+supero-inferior direction.
+
+The cervical region is not a single curve, as in the human being. It
+presents two: one superior, with its convexity looking upwards; the
+other inferior, the convexity of which is turned downwards. This
+arrangement reminds one of that of a console.
+
+The dorsal and lumbar regions are placed in a single curved line, more
+or less concave downwards; so that in the lumbar region there is no
+curve analogous to that which exists in man; a form which, in the
+latter, is due to the biped attitude--that is to say, the vertical
+position of the trunk. Briefly, there is in quadrupeds one dorso-lumbar
+curve; and not both a dorsal and a lumbar, with convexities in opposite
+directions.
+
+At the extremity of the dorso-lumbar region is the sacrum and the caudal
+appendix, which describe a curve of which the concavity is directed
+downwards and forwards.
+
+It is necessary to point out that it is not the curves of the three
+anterior portions of the spinal column which determine the form of the
+superior border of the neck and shoulders, and of the same part of the
+trunk. For the first portion, there is a ligament which surmounts the
+cervical region, and substitutes its modelling influence for that of the
+vertebræ. It is the _superior cervical ligament_, which arises from the
+spinous process of the first cervical vertebræ, and is inserted into the
+external occipital protuberance on the upper part of the posterior
+surface of the skull. The summits of the spinous processes of the
+vertebræ alone give form to the superior median border of the trunk. In
+this connection we here repeat that it is not the general curvature of
+the vertebral column which produces the withers, but the great length of
+the spinous process of the first vertebræ of the dorsal region.
+
+
+The Thorax
+
+The dorsal vertebræ form the posterior limit in man, and superior in
+quadrupeds, of the region of the trunk known as the _thorax_. A single
+bone, the sternum, is situated at the aspect opposite; the ribs bound
+the thorax on its sides.
+
+In its general outlines the thorax in quadrupeds resembles that
+of man--that is to say, that, as in the latter, the anterior
+portion--superior in the human being--is narrower than the part
+opposite. But the progressive widening takes place in a more regular and
+continuous fashion, so that it presents a more definitely conical
+outline. This purely conical form is nevertheless found in the human
+species, but only during infancy; the inferior portion of the thoracic
+cage being then widely expanded, because of the development of the
+abdominal viscera, which at that period are relatively large.
+
+But the proportionate measurements of the thorax are different. Indeed,
+we may recall that in man the thorax is flattened from before backwards,
+so that the distance between the sternum and the vertebral column is
+shorter than the distance from the rib of one side to the corresponding
+one of the opposite side (Fig. 5). In animals, on the contrary, it is
+flattened laterally. Its vertical diameter--measured from the sternum to
+the vertebral column--is greater than the transverse measurement (Fig.
+6).
+
+[Illustration: FIG. 5.--A TRANSVERSE SECTION OF THE THORAX OF A MAN
+PLACED VERTICALLY--THAT IS TO SAY, IN THE DIRECTION WHICH IT WOULD
+ASSUME IN A MAN PLACED IN THE ATTITUDE OF A QUADRUPED (A DIAGRAMMATIC
+FIGURE).
+
+1, Dorsal vertebra; 2, sternal region; 3, costal region of one side; 3´,
+costal region of the other side.]
+
+From this results a peculiar arrangement of the muscles that we are able
+to bring directly into prominence, which presents points of interest
+from the point of view of the contraction of the subcutaneous layer.
+Indeed, in man the region occupied by the pectorals is very broad; it is
+a wide surface turned directly forward. In quadrupeds, this region of
+the pectorals is narrowed. It is not spread out, as in the preceding
+instances; and the appearance it presents is explained by the fact that
+the thorax is compressed laterally. If we examine the thorax on one of
+its lateral surfaces, the muscles, on the contrary, are more extended.
+We see the contour of the vertebral column, and the median part of the
+abdomen; and, especially in the horse, between the great dorsal and the
+great oblique of the abdomen, we find a large space, in which the ribs,
+with the intercostals which join them, are uncovered; the muscles in
+question separate the one from the other, under the influence, it would
+seem, of the great dimensions of the lateral wall of the thorax.
+
+[Illustration: FIG. 6.--A VERTICAL SECTION OF THE THORAX OF A QUADRUPED
+(DIAGRAMMATIC).
+
+1, Fifth dorsal vertebra; 2, sternal region; 3, costal region of one
+side; 3´, costal region of the opposite side.]
+
+=The Sternum.=--The sternum is, in quadrupeds, directed obliquely
+downwards and backwards; its form varies in different species. In the
+carnivora, it consists of eight bones, irregularly cylindrical in form,
+being slightly flattened from within outwards, and thickened at their
+extremities. They remain separate, and this contributes elasticity and
+flexibility to the thorax. The first nine costal cartilages articulate
+directly with the sternum. The first of these cartilages articulates
+with a nodule situated a little above the middle of the first bone of
+the sternum.
+
+In the horse the sternum is flattened laterally in its anterior portion,
+and from above downwards in its posterior half. The six bones which
+form the sternum are connected by cartilage. The keel-shaped piece,
+situated in front of the sternum, is also cartilaginous. This process,
+but slightly marked posteriorly, becomes more and more prominent in
+front, and terminates at its anterior extremity by a prolongation,
+slightly curved backwards, which projects for some centimetres beyond
+the cavity in which the first costal cartilage is received. This process
+is known as the _tracheal process_, or _rostral cartilage_. The
+posterior extremity of the sternum, flattened from above downwards, ends
+in a cartilaginous plate; concave superiorly, and convex inferiorly:
+this is the abdominal prolongation, or _xiphoid appendix_.
+
+In the ox, the sternum is formed of two distinct bones, which are united
+by an articulation. One, the anterior, is short, and forms the first
+portion of the sternum; it is slightly flattened from side to side, and
+vertical in direction. The other, the posterior, is longer, and is
+formed by the fusion of several small bones; it is placed horizontally,
+and is flattened from above downwards. At the level of articulation of
+these two portions, and because of their different directions, the bone
+is bent. This bend occurs at the point of articulation of the second
+costal cartilage. On the superior border of the anterior segment the
+cartilage of the first rib is articulated. The xiphoid appendix, which
+is cartilaginous, is attached to the extremity of a long process of the
+last bone of the sternum.
+
+The shape of the anterior extremity of the sternum is influenced by the
+presence or absence of clavicles. We have seen that in some quadrupeds
+the clavicles are wanting. In the first case, this extremity is large,
+and approaches in shape to the corresponding part of the human sternum,
+which is so clearly designed to give a point of support to the anterior
+bone of the shoulder. In the second, on the contrary, this extremity is
+narrow.
+
+The sternum in birds is very different from that in mammalia, which we
+have been studying. It varies greatly in extent and shape, under the
+influence of certain conditions. To understand the cause of these
+variations it is necessary to remember that in man (as, indeed, in other
+animals; but the example of man, for that which follows, will be more
+striking, on account of the mobility of his upper limbs) the sternum
+gives origin to the pectoral muscles, and that these muscles are
+inserted into other parts of the thoracic limbs, designed by their
+contraction to draw the arms downwards, forwards, and inwards--that is,
+when these are in a state of abduction and in a horizontal direction,
+they draw them towards the anterior surface of the thorax and downwards.
+Now, this movement is similar to that made by birds during flight. It is
+necessary to add that, in the latter case, the more the displacement of
+the upper limbs has of force and extent, the more the pectoral muscles
+are developed.
+
+For these reasons, birds, in which, during flight, the movements of the
+thoracic limbs--the wings--are necessarily energetic, present a great
+development of the pectoral muscles; having consequently, because an
+extent of surface for the origin of the muscles commensurate with their
+development is necessary, a very large and peculiarly shaped sternum
+(Figs. 18, 6; and 21, 6). Indeed, not only is the sternum large, but,
+further, in order to form a deeper surface, proportionately adapted to
+the muscles which arise from and cover it, its anterior surface
+presents, in the median line, a prominent crest known as the _keel_.
+This prominence forms two lateral fossæ. We cite as examples, the
+sternum of the eagle, the vulture, the falcon, and the hawk.
+
+All birds are not, however, equally adapted to flight, for in the
+domestic cock, which flies but a short distance, and badly, the sternum
+is less developed (Fig. 7); it is also diminished by slots, which
+diminish its surface. These slots, two on each side, are called from
+their position the internal and external slots. They are bounded by
+narrow, elongated, bony processes, an internal and an external; the
+expanded lower extremity of the latter overlaps the last inferior ribs
+(see p. 19). The part of the external border which surmounts this
+external process is hollowed out into grooves, which receive the
+inferior ribs, and terminates superiorly in an osseous projection known
+as _the costal prominence_.
+
+In the ostrich, the cassowary, and the apteryx, which run, but do not
+fly, the sternum has the form of a plate of bone slightly convex, but
+without a keel.
+
+[Illustration: FIG. 7.--STERNUM OF A BIRD (THE COCK): LEFT SIDE,
+EXTERNAL SURFACE.
+
+1, Keel; 2, internal slot; 3, external slot; 4, internal process; 5,
+external process; 6, inferior ribs; 7, costal process; 8, surface for
+articulation with the coracoid bone.]
+
+The shape of the sternum, correlated to the faculty of flight (or of
+swimming; apropos of which we may cite the penguin, of which the
+rudimentary wings resemble fins, and perform their functions only), or
+the absence of this faculty, has furnished the division of birds into
+two groups. In one are included, under the name _Carinates_ (_carina_,
+keel), those in which the sternum is provided with a keel; in the other
+division are those in which the sternum is not furnished with one. These
+latter, on account of their unique mode of progression, are more nearly
+allied to the mammals.
+
+The keel is developed in flying mammals (bats).
+
+=Ribs and Costal Cartilages.=--There are on each side of the thorax as
+many ribs as there are dorsal vertebræ. In animals, as in man, the ribs
+which articulate with the sternum by their cartilages are called _true_,
+or _sternal_ ribs; those whose cartilages do not articulate with the
+sternum are called _false_, or _asternal_. The longer ribs are those
+situated in the middle region of the thorax.
+
+The ribs are directed obliquely downwards and backwards, and this
+obliquity is more marked in the posterior ones than in the anterior.
+They are, however, less oblique than in the human being; what proves
+this is that the first rib in man is oblique, while in quadrupeds it is
+vertical.
+
+The curvature of the ribs is less pronounced in quadrupeds than in the
+human being, but this is not equal in all animals. The ribs of the bear
+are more curved than those of the dog; the latter has ribs more curved
+than those of the horse.
+
+Each rib, at its vertebral extremity, presents, from within outwards, a
+wedge-shaped head for articulation with two dorsal vertebræ, a neck, and
+a tuberosity. External to the tubercle are found some rough impressions,
+for muscular attachments, which correspond to the angle of the human
+rib.
+
+In the following table, we give the number and classification of the
+ribs of some animals:
+
+NUMBER OF THE RIBS ON EACH SIDE OF THE THORAX.
+
+                             Sternal.    Asternal.
+  Bear       14  divided into   9    and     5
+  Dog        13     "      "    9     "      4
+  Cat        13     "      "    9     "      4
+  Rabbit     12     "      "    7     "      5
+  Pig        14     "      "    7     "      7
+  Horse      18     "      "    8     "     10
+  Camel      12     "      "    8     "      4
+  Ox         13     "      "    8     "      5
+  Sheep      13     "      "    8     "      5
+
+The costal cartilages, by which the first ribs are united to the sternum
+(sternal ribs), whilst the latter are united one to the other without
+being directly connected with the sternum (asternal ribs), are, as a
+rule, in quadrupeds, directed obliquely downwards, forwards, and
+inwards; each forms, with the rib to which it belongs, an obtuse angle
+more or less open anteriorly. Their length is proportionate to that of
+the ribs. The cartilages, which are continued from the asternal ribs,
+unite and form the borders, directed obliquely downwards and forwards,
+of the fossa which is found at the inferior and posterior part of the
+thorax, and which forms the lateral limits of the epigastric region. In
+the dog and cat the ribs are thick and almost cylindrical; the costal
+cartilages are thicker at the margin of the sternum than at their costal
+extremity. In the ox, the ribs are flattened laterally and are very
+broad, the more so as we examine a portion further from the vertebral
+column. From the second to the twelfth they are quadrangular in the
+superior fourth, and thicker than in the rest of their extent. The first
+costal cartilage is vertical; the following ones are progressively more
+oblique in a direction downwards and forwards. The four or five
+cartilages which succeed the first unite with slight obliquity to the
+sternum; their union with that bone gives the impression of a very
+strong, well-knit apparatus. The costal cartilages which unite with the
+sternum are flattened laterally in the portions next the ribs, and
+flattened from front to back in the rest of their extent.
+
+In the horse the ribs increase in length from the first to the ninth;
+they are flattened from without inwards, and increase in width from the
+first to the sixth or seventh, and the following ones become narrower.
+The costal cartilages, from the second to the eighth, are, as in the ox,
+at first flattened laterally, near the ribs; while near the sternum they
+are flattened from front to back.
+
+In birds, the ribs are each furnished with a flat process (Fig. 18, 10),
+which springs from the posterior border, is directed backwards, and
+overlaps the external surface of the succeeding rib. These processes are
+not found, as a rule, on the first or last ribs.
+
+As for the costal cartilages, they are, as a rule, ossified, and receive
+the name of inferior ribs (Fig. 18, 11), united to the preceding
+(superior ribs; Fig. 18, 9) by articulation; by the other extremity they
+are joined to the sternum; the first superior ribs generally want them.
+Sometimes the last inferior rib becomes connected with the one that
+precedes it, not articulating with the sternum; and thus recalls the
+relations of the asternal ribs which we have noticed in our study of the
+mammals.
+
+In the bat, as in birds, the costal cartilages are ossified.
+
+
+THE ANTERIOR LIMBS[5]
+
+  [5] Consult Figs. 21, 33, 34, 38, 39, 46.
+
+The anterior limbs, homologous to the upper limbs in man, are formed, as
+in the latter, of four segments: the shoulder, the arm, the forearm, and
+the hand. These limbs, considered in the vertebral series, present
+themselves under very different aspects, which are determined by the
+functions they are called upon to perform.
+
+They constitute the forepaw in terrestrial mammals; in aerial
+vertebrates they form wings; in aqueous mammals they act as paddles. In
+whatever series we study them, we can readily find the relationship of
+the different parts; it is very easy to recognise the same bones in the
+upper limbs of the human being, the wings of the bat (Fig. 8) and of
+birds (Fig. 21), and in the anterior paddles of the seal (Fig. 9) and of
+the dolphin.
+
+[Illustration: FIG. 8.--ANTERIOR LIMB OF THE BAT: LEFT SIDE, ANTERIOR
+SURFACE.
+
+1, Clavicle; 2, scapula; 3, humerus; 4, radius; 5, cubitus; 6, carpus;
+7, thumb; 8, metacarpus; 9, phalanges.]
+
+In quadrupeds, the shoulder and arm are hidden, the latter more or less
+completely, in the muscular mass which binds it to the lateral wall of
+the trunk; so that the anterior limbs only present; free from the trunk:
+the elbow, forearm, and hand.
+
+
+The Shoulder
+
+In some vertebrates, the shoulder is formed of two bones--the scapula
+and clavicle; in others of only one bone--the scapula; the clavicle in
+this case does not exist.
+
+=The Scapula or Omoplate.=--The scapula is situated on the lateral
+surface of the thorax, and is directed obliquely, from above downwards
+and from behind forwards.
+
+We must first recall, so as to be able to make a comparison, that in man
+this bone is placed at the posterior surface of the thoracic cage; so
+that if we look at the human thorax on one of its lateral aspects we see
+chiefly the external border of the scapula; it is the external surface
+(homologous to the posterior surface of the human scapula) which we see
+in its full extent when we look on the same surface of the thorax in
+quadrupeds.
+
+[Illustration: FIG. 9.--ANTERIOR LIMB OF THE SEAL: LEFT SIDE, EXTERNAL
+SURFACE.
+
+1, Scapula; 2, humerus; 3, radius; 4, ulna; 5, carpus; 6, metacarpus; 7,
+phalanges of the fingers.]
+
+To sum up, if we fancy the human being in the position of the quadruped,
+the scapula will have its surfaces almost parallel to the ground (Fig.
+10); while in quadrupeds, the surfaces are situated in a plane which is
+almost perpendicular to the ground (Fig. 11). This position of the
+scapula in an almost vertical plane is designed to give the necessary
+point of support to the osseous columns that form the skeleton of the
+other portions of the anterior limbs.
+
+Because of this position of the scapula (Figs. 12 and 13), the spinal
+border is superior, the cervical, anterior, and the axillary, posterior.
+In direct contrast to what obtains in the human scapula, the spinal
+border is the shortest of the three; except in the bat, and the
+majority of the cetaceans.
+
+[Illustration: FIG. 10.--SITUATION AND DIRECTION OF THE SCAPULA IN THE
+HUMAN BEING, THE TRUNK BEING HORIZONTAL, AS IN QUADRUPEDS. VERTICAL AND
+TRANSVERSE SECTION OF THE THORAX (DIAGRAMMATIC FIGURE).
+
+1, Contour of the thorax; 2, 2, the scapula.]
+
+[Illustration: FIG. 11.--POSITION AND DIRECTION OF THE SCAPULA IN
+QUADRUPEDS. VERTICAL AND TRANSVERSE SECTION OF THE THORAX (DIAGRAMMATIC
+FIGURE).
+
+1, Contour of the thorax; 2, 2, the scapula.]
+
+In certain animals (in the ungulates [_hoofed_[6]]--pigs, oxen, sheep,
+horses) the superior, or spinal, border of the scapula is surmounted by
+a cartilage called _the cartilage of prolongation_.
+
+  [6] For the definition of the word _hoofed_, see p. 37.
+
+This is the cause why the border to which it is fixed is so slightly
+noticeable under the skin in these animals; indeed, in the upper part,
+the bone and cartilage are not distinguishable in the contour of the
+corresponding region of the back; being applied to the lateral surfaces
+of the spinous processes, the prominence formed by the extremities of
+which is directly continuous with the plane of the scapula (Fig. 16).
+
+[Illustration: FIG. 12.--LEFT SCAPULA OF THE HUMAN BEING, POSTERIOR
+SURFACE, PLACED IN THE POSITION WHICH IT WOULD OCCUPY IN THE SKELETON OF
+A QUADRUPED.
+
+1, Cervical border; 2, spinal border; 3, axillary border; 4,
+supraspinous fossa; 5, subspinous fossa; 6, scapular spine; 7, glenoid
+cavity; 8, coracoid process; 9, acromion process.]
+
+[Illustration: FIG. 13.--LEFT SCAPULA OF A HORSE: EXTERNAL SURFACE.
+
+1, Cervical border; 2, spinal border--the scapula here represented,
+being from a hoofed animal, has a cartilage of extension attached to its
+spinal border; 3, axillary border; 4, supraspinous fossa; 5, subspinous
+fossa; 6, spine of the scapula; 7, glenoid cavity; 8, coracoid process.
+The scapula of the horse has no acromion process, but it is easy, if we
+compare the human scapula, to judge of the position which this process
+would occupy if it were present.]
+
+In quadrupeds whose scapula, on the contrary, is wanting in the
+cartilage of prolongation (in the _clawed_,[7] such as the cat and dog),
+the superior border of the scapula is visible, especially when the
+animal is resting on its fore-limbs, particularly when it crouches; at
+such a time the skin is markedly raised by that border; and the spinous
+processes of the vertebræ, beyond which it projects, occupy the bottom
+of a fossa (Fig. 15). The internal surface of the scapula is turned
+towards the ribs; it is known, as in man (in whom this surface is
+anterior), as the subscapular fossa.
+
+  [7] For the definition of this word, see p. 37.
+
+[Illustration: FIG. 14.--VERTICAL AND TRANSVERSE SECTION, AT THE SITE OF
+THE SHOULDERS, OF THE THORAX OF THE HORSE (DIAGRAMMATIC FIGURE).
+
+1, Outline of the thorax at the level of the third dorsal vertebra; 2,
+2, scapula; 3, spinal border of the scapula; 4, cartilage of
+prolongation; 5, contour of the skin.]
+
+[Illustration: FIG. 15.--VERTICAL AND TRANSVERSE SECTION, AT THE PLANE
+OF THE SHOULDERS, OF THE THORAX OF A DOG (DIAGRAMMATIC FIGURE).
+
+1, Outline of the thorax at the level of the third dorsal vertebra; 2,
+2, scapula; 3, spinal border of the scapula; 4, contour of the skin.]
+
+Its external surface is divided into two parts by the spine of the
+scapula; which, in some animals, terminates inferiorly in a flat and
+clearly distinct process, the homologue of the acromion process of the
+human scapula. The two regions separated by the spine are known as the
+supraspinous fossa and the infraspinous fossa. The supraspinous fossa is
+anterior to the spine, and the infraspinous is posterior to it. The
+surfaces of the scapula are, in quadrupeds, flatter than in the human
+being, and in particular the subscapular fossa, which is also less
+concave. Some authors attribute this to the lesser curvature of the ribs
+in quadrupeds. A few words will suffice to prove that there must be
+another reason. The scapula is not in immediate contact with the ribs;
+the subscapular fossa is not moulded on them. Besides, the form of the
+scapula is, as in other parts of the skeleton, dependent on the
+disposition of muscles, and the development of these latter is
+correlated to the extent and energy of the movements which the
+individual is able or required to execute. But the movements which
+those muscles produce (more especially the rotation of the humerus) are,
+in quadrupeds, less extensive than in the human being; and,
+consequently, the muscles which produce them are, proportionally, less
+strongly developed. The inferior angle (superior and external in man),
+situated at the junction of the cervical and axillary borders, presents
+the glenoid cavity, which, looking downwards, receives the articular
+surface of the superior extremity of the bone of the arm--that is to
+say, the head of the humerus. Above this cavity, on the lower part of
+the cervical border, is situated a tubercle which reminds us of the
+coracoid process of the human scapula. The region occupied by the
+glenoid cavity is separated from the body of the bone by a
+constriction--the neck of the scapula.
+
+In birds the scapula is elongated in a direction parallel to the
+vertebral column, and very narrow in the opposite (Fig. 18): it is also
+flat, and has no spine. Its coracoid process is represented by a
+peculiar bone--the coracoidean or coracoid bone--which we shall describe
+later on when we come to the study of the clavicle and of the anterior
+region of the shoulder (see p. 26).
+
+=The Clavicle.=--The clavicle is found only in the human being, and in
+animals whose anterior limbs, possessing great freedom of movement in
+all directions, require that the scapula should possess a point of
+support which, while affording this, can be displaced with it, or draw
+it in certain directions. Now, this point of support is furnished by the
+clavicle.
+
+In animals possessed of hoofs (ungulates), such as the sheep, ox, and
+horse, the clavicle does not exist. Indeed, in them the freedom of
+movement of the anterior limbs is limited; they move by projection in
+the forward and backward directions only; they merely fulfil the
+functions of giving support to and carrying about the body. The clavicle
+is rudimentary in the cat and the dog; in the cat it is a small,
+elongated bone (Fig. 16), 2 centimetres in length, thin and curved,
+connected with the sternum and the scapula by ligamentous bundles. In
+the dog it is represented by a small osseous plate only (Fig. 17),
+which is not connected with any of the neighbouring bones.
+
+It is on the deep surface of a muscle which passes from the head and
+neck to the humerus (mastoido-humeral, a muscle common to the arm, neck,
+and head) in which this rudimentary bone is found to be developed.
+
+The clavicle exists in perfect state in mammals which use their limbs
+for digging, grasping, or flying; the insectivora (hedgehog, mole) and
+some rodents (squirrel, woodchuck) are provided with it.
+
+The cheiroptera (bats) possess an extremely well-developed clavicle, on
+account of the varied movements which their thoracic limbs execute.
+
+[Illustration: FIG. 16.--LEFT CLAVICLE OF THE CAT: SUPERIOR SURFACE
+(NATURAL SIZE).
+
+1, Internal extremity; 2, external extremity.]
+
+[Illustration: FIG. 17.--CLAVICLE OF THE DOG (NATURAL SIZE).]
+
+This formation of the shoulder which favours flight in the bat is even
+more remarkable in birds. In these latter (Fig. 18) the clavicles, fused
+together by their lower extremities, form one bone, having the shape of
+the letter V or U, which is known as the _fourchette_; this bone, acting
+as a true spring, keeps the shoulders apart, and prevents their
+approximation during the energetic movements which flight necessitates.
+
+In birds whose power of flight is strong, the two limbs of this bone are
+widely separated and thick, and the fourchette is U-shaped. Those whose
+flight is awkward and but slightly energetic have the limbs of the
+fourchette slender; they unite at a more acute angle, and the bone is V
+shaped.
+
+Furthermore, a bone named the _coracoid_ joins the scapula to the
+sternum; this bone, often fused with the scapula, where it contributes
+to the formation of the glenoid cavity, represents in birds the coracoid
+process of the human scapula. If we fancy this process directed
+inwards, and sufficiently lengthened to join the sternum, we shall have
+an idea of the disposition of the bone we are now discussing, and the
+reasons for which the name has been chosen by which it is designated.
+The coracoid bone, like the fourchette which it reinforces, offers to
+the wings a degree of support proportionate to the efforts developed by
+those limbs; for this reason it is thick and solid in birds of powerful
+flight.
+
+[Illustration: FIG. 18.--SKELETON OF THE SHOULDER OF A BIRD (VULTURE):
+ANTERO-EXTERNAL VIEW OF THE LEFT SIDE.
+
+1, Left clavicle; 2, inferior portion of the right clavicle, forming by
+its ankylosis with that of the other side the fourchette; 3, coracoid
+bone; 4, scapula; 5, articular surface for humerus; 6, superior half of
+the sternum; 7, keel of sternum; 8, spinous process of the dorsal
+vertebræ; 9, superior ribs; 10, process of one of these ribs; 11,
+inferior ribs.]
+
+The superior extremity of each branch of the fourchette, at the level of
+its junction with the coracoid and the scapula, bounds, with these
+latter, a foramen which gives passage to the tendon of the elevator
+muscle of the wing, or small pectoral. The importance of the fourchette
+being, as we have seen, in proportion to the movements of flying, it is
+easy to understand that the bone is not found in the ostrich.
+
+
+The Arm
+
+A single bone, the humerus, forms the skeleton of this portion of the
+thoracic limb.
+
+=The Humerus.=--The bone of the arm is, in quadrupeds, inclined from
+above downwards and from before backwards.
+
+It is, with relation to other regions, short in proportion as the
+metacarpus is elongated, and as the number of digits is lessened. In the
+horse, for example, whose metacarpus is long, and in which but one digit
+is apparent, the humerus is very short. The slight development in length
+of the humerus explains its close application to the side of the animal
+as far as the elbow.
+
+In animals in which the humerus is longer, the bone is slightly free, as
+well as the elbow, at its inferior extremity. Later on we will return to
+the consideration of this peculiarity and of the proportions of the
+humerus, after we have studied the other parts of the fore-limbs.
+
+The humerus in quadrupeds is inflected like the letter S; in man this
+general form is less accentuated, the humerus being almost straight. On
+its body, which appears twisted on its own axis, we find the
+musculo-spiral groove,[8] which crosses the external surface, and is
+very deep in some animals. Above this groove, and on the external
+surface, there exists a rough surface which is the impression of the
+deltoid. In some species this rugosity is very prominent, and is called
+_the tuberosity of the deltoid_; it is prolonged downwards by a border
+which forms the anterior crest of the musculo-spiral groove and limits
+this latter in front. The external border of the bone, or posterior
+crest of the groove, limits it behind.
+
+  [8] It would be going outside our province to discuss whether the
+      humerus is really twisted on its axis. This question, often
+      discussed, has been solved in some recent works in the following
+      manner: the humerus has undergone torsion at the level of its
+      superior extremity, and not at the level of its body; this does
+      not authorize us further to accord any definite sense to the
+      denomination 'groove of torsion' (musculo-spiral groove). That
+      which we must especially remember in connection with this fact,
+      is, as we shall afterwards see, the difference of direction which
+      the articular head presents according as the torsion has been more
+      or less considerable: because this is established, according to
+      the same order, in man and in quadrupeds.
+
+The superior extremity is enlarged, and remarkable in three portions
+which it presents; these are: an articular surface and two tuberosities.
+
+The articular surface, or head of the humerus, smooth and round, is in
+contact with the glenoid cavity of the scapula. This head in the human
+skeleton is directed upwards and inwards; in quadrupeds its direction is
+upwards and backwards. The inferior extremity, having in both one and
+the other its long axis directed transversely, and the point of the
+elbow looking backwards in all, the result is that the head of the
+humerus is not situated vertically above the same regions; in the first,
+it is almost directly above the internal part of this extremity; in the
+latter, it is situated above its posterior surface, or the point of the
+elbow in the complete skeleton. This difference of direction is
+correlated with the position of the scapula, the glenoid cavity of
+which, as we have already seen, is in man turned outwards, whereas in
+quadrupeds it looks downwards. In the latter case the scapula
+consequently rests on the head of the humerus; and this position is most
+favourable for the performance of the functions which the anterior limbs
+have to fulfil in these latter.
+
+Of the tuberosities of the head of the humerus, one is situated on the
+external aspect--it is the great tuberosity, or _trochiter_; the other
+is placed internally--it is the small tuberosity, or _trochin_. The
+great tuberosity is divided into three parts--summit, convexity, and
+crest; these different parts give insertion to the muscles of the
+shoulder. We recollect that the facets (anterior, middle, and posterior)
+of the great tuberosity of the humerus in man give attachment to the
+muscles of the same region. The head of the humerus in the human body
+projects above the tuberosities. We shall see afterwards, when dealing
+with some special quadrupeds, that in some of these, on the other hand,
+the tuberosities are on a higher level than the articular head of the
+bone. Between the two tuberosities is the bicipital groove.
+
+In man, the superior extremity of the humerus, although covered by the
+deltoid, reveals its presence by elevating the corresponding portion of
+the latter. In quadrupeds, the anterior part of this extremity, although
+similarly covered by muscular bundles, produces a prominence under the
+skin. This prominence is situated at the summit of the angle formed by
+the opposing directions of the scapula and the bone of the arm, and
+constitutes what is known by the name of the _point of the shoulder_, or
+of the _point of the arm_.
+
+The inferior extremity, transversely enlarged, presents an undulating
+articular surface, which reminds us of the trochlea and the condyle of
+the human humerus; on which, however, the condyle is more sharply
+defined from the trochlea.
+
+In the human skeleton, the internal lip of the trochlea descends lower
+than the external; and also lower than the condyle. In the bear, the
+cat, and the dog, it is the same. In the ox and the sheep, the condyle
+is lower than the trochlea, but only very little lower. In the horse the
+arrangement is still the same, but a little more accentuated.
+
+On the lateral parts of this extremity we find: internally, a
+prominence, the epitrochlea; and, externally, another, the epicondyle.
+It is from this latter that the crest arises, which, passing upwards,
+forms the posterior limit of the groove of torsion.
+
+The two prominences, which we have just described from a general point
+of view, present special arrangements which it is necessary to point
+out. When we examine the form of the outline of the inferior extremity
+of the humerus in man, the bear, the cat, the dog, the ox, and the
+horse, we find in following this order that the extremity tends to
+become narrow transversely, and that the epicondyle and the epitrochlea
+are less and less prominent on the external and internal aspects
+respectively. These two processes, indeed, project backwards; the
+epitrochlea always remaining more developed than the epicondyle. Because
+of this projection backwards, the cavity situated on the posterior
+surface of the inferior extremity, the olecranon fossa, is very deep,
+more so than in the humerus of man. Its borders being thus formed by the
+two processes, are very prominent. In front we find the coronoid fossa,
+which is less deep than that of which we have just spoken.
+
+There exists in some mammals an osseous canal, situated above the
+epitrochlea, and known as the _supratrochlear canal_ (Fig. 19). It is
+bounded by a plate of bone which at its middle portion is detached from
+the shaft of the humerus, and blends with the latter at both its
+extremities. The brachial artery and median nerve pass through the
+foramen.
+
+[Illustration: FIG. 19.--INFERIOR EXTREMITY OF THE LEFT HUMERUS OF A
+FELIDE (LION).
+
+1, Epitrochlea; 2, supra-epitrochlear foramen.]
+
+[Illustration: FIG. 20.--INFERIOR EXTREMITY OF THE LEFT HUMAN HUMERUS,
+SHOWING THE PRESENCE OF A SUPRATROCHLEAR PROCESS.
+
+1, Epitrochlea; 2, supra-epitrochlear process.]
+
+A similar condition is sometimes found, as an abnormality, in
+man, which presents itself under the following aspect (Fig.
+20): an osseous prominence more or less long, in the shape of a
+crochet-needle--supra-epitrochlear process--situated 5 or 6 centimetres
+above the epitrochlea; the summit of this process gives attachment to a
+fibrous band, which is inserted by its other end into the epitrochlea
+and the internal intermuscular aponeurosis. The fibro-osseous ring thus
+formed gives passage to the brachial artery and the median nerve, or in
+case of a premature division of this artery to the ulnar branch of the
+same.[9]
+
+  [9] For further details of this anomaly, see Testut, 'The Epitrochlear
+      Process in Man' (_International Journal of Anatomy and
+      Physiology_, 1889); A. Nicolas, 'New Studies on the Supratrochlear
+      Process in Man' (_Review of Biology of the North of France_, t.
+      iii., 1890-1891).
+
+There is also found in some mammals a perforation of the thin plate of
+bone which, in others, separates the olecranon fossa from the coronoid.
+This perforation is sometimes found as an abnormality in the human
+humerus.
+
+As does the sternum and the skeleton of the shoulder, the humerus of
+birds presents differences correlated to the functions which the
+thoracic limbs are destined to fulfil. Lying on the side of the thorax,
+directed obliquely downwards and backwards (Fig. 21), it is
+proportionately longer in individuals of powerful flight than in those
+which fly less or not at all. In the vulture it projects beyond the
+posterior part of the pelvis; in the cock it does not even reach the
+anterior border of the same. To these differences in length are added
+differences in volume and in the development of the processes which
+serve for muscular attachment, which are more considerable in birds of
+powerful flight.
+
+The humerus is so placed that the radial border, external in man and
+quadrupeds, looks upwards, with the result that the surface of the bone
+of the arm, which in these latter is anterior, in the former looks
+outwards. The humeral head, which is turned forwards and a little
+inwards, is convex and elongated in the vertical direction. Behind and
+above this head is found a crest for the insertion of muscles. It is the
+same for the region below, where there is a tuberosity whose inferior
+surface presents a pretty large opening which looks inwards to a fossa
+from the floor of which a number of minute openings communicate with the
+interior of the bone. This is the pneumatic foramen of the humerus.
+
+It is of interest to remember in connection with this subject that in
+birds, in keeping with the conditions of flight, every system of organs
+is adapted to diminish the weight of the body. We particularly draw
+attention to the osseous framework, the structure of which is such that
+the weight of the animal is greatly lessened. This condition is secured
+by the pneumaticity. The bone consists of a cover of compact tissue,
+which, instead of enclosing marrow, is hollowed out by cavities which
+contain air, and communicate with special pouches, the air-sacs, which
+are appendages of the lungs.[10]
+
+  [10] The presence of air in the bones does not seem to be always
+       associated with the power of flight; as a matter of fact, we find
+       air spaces in the bones of some birds which do not fly (E. J.
+       Marey, 'The Flight of Birds,' Paris, 1890, p. 51).
+
+[Illustration: FIG. 21.--SKELETON OF A BIRD (VULTURE): LEFT SURFACE.
+
+1, Cranium; 2, face; 3, cervical vertebræ; 4, spinous processes of the
+dorsal vertebræ; 5, coccygeal vertebræ; 6, sternum; 7, keel; 8, superior
+ribs; 9, inferior ribs; 10, clavicle; 11, coracoid bone (for the details
+of the skeleton of the shoulder, see Fig. 18); 12, humerus; 13, radius;
+14, ulna; 15, carpus; 16, hand (for details of the skeleton of this
+region, see Fig. 31); 17, ilium; 18, ischium; 19, pubis (for the details
+of the pelvis, see Fig. 46); 20, femur; 21, tibia; 22, fibula; 23,
+osseous nodule, which some anatomists think represents the calcaneum; it
+is the sole vestige of the tarsus; 24, metatarsus; 25, foot; 26, first
+toe (for the details of the skeleton of the foot, see Fig. 48).]
+
+The antibrachial extremity of the humerus is flattened from without
+inwards. It terminates in two articular surfaces, which articulate with
+the radius and ulna.
+
+The olecranon process of the ulna being slightly developed, it follows
+that the olecranon fossa is not large; neither is the coronoid.
+
+
+General View of the Form of the Forearm and Hand
+
+We now proceed to the study of the two regions of the fore-limbs which
+present the greatest variety in regard to the number of bones and also
+in regard to form and proportions. These two regions are the forearm and
+the hand.
+
+It is first of all necessary to say that in man, when the fore-limb
+hangs beside the body, and the dorsum of the hand looks backwards, the
+two bones of the forearm are parallel, and that this position is known
+by the name of _supination_. It is also necessary to remember that there
+is another attitude, in which the radius, crossing the ulna, and
+carrying the hand with it, displaces the latter in such a way that the
+palmar surface looks backwards. This second position is known as
+_pronation_.
+
+Let us now suppose that a man wishes to walk in the attitude of a
+quadruped. It will be necessary, in order that his upper limbs, being
+for the moment anterior ones, may act as members of support, to place
+the forearm in pronation, in order that, as is more normal, the hands
+may rest on the ground by their palmar surfaces. In this position the
+radius, being rotated on its own axis at its upper extremity and around
+the ulna in the rest of its extent, shall have its inferior extremity
+situated on the inner side of the corresponding extremity of the latter.
+
+Such is the situation of the bones of the forearm and the attitude of
+the hand in quadrupeds. In short, quadrupeds have their anterior members
+in the position of pronation.
+
+The individual whom we have just supposed placed in the attitude of a
+quadruped would be able to maintain this position by pressing on the
+ground more or less extensive portions of his hands; the whole palm of
+the hand may be applied to the ground (Fig. 22); or the fingers
+only--that is to say, the phalanges (Fig. 23); or the extremities of
+the fingers only--that is to say, the third phalanges (Fig. 24). This
+last position, which is certainly difficult to maintain, should here be
+regarded rather as theoretical.
+
+We shall meet with each of these modes of support in certain groups of
+animals. Thus, the bear, badger, and the majority of rodents, have the
+paws applied to the ground by the whole extent of the palmar surface of
+the hand, from the wrist to the tips of the fingers. They are therefore
+called plantigrade, from the analogy, in this case, of the palm of the
+hand to the plantar surface, or sole of the foot.
+
+[Illustration: FIG. 22.--THE HUMAN HAND RESTING FOR ITS WHOLE EXTENT ON
+ITS PALMAR SURFACE: LEFT SIDE, EXTERNAL SURFACE.]
+
+In others, such as the lion, tiger, panther, cat, wolf, and fox, the
+support is made no longer on the whole extent of the palmar surface, but
+on the corresponding surface of the fingers only--the metacarpus is
+turned back, and, consequently, the wrist--that is to say, the
+carpus--is removed from the ground. These are the digitigrades.
+
+Lastly, the ruminants (sheep, oxen, deer, etc.), and also the pig, ass,
+and horse, rest on the third phalanx only. In them not only is the
+metacarpus turned back, but also the two first phalanges. The wrist is
+very far removed from the ground. In these animals, the third phalanx is
+enclosed in a case of horn, a nail (the hoof), and because the support
+of the limb is on that nail, the name of unguligrades has been given
+them. Nevertheless, as the point of support is on the third phalanx,
+which is also known by the name of phalangette, we are of opinion that,
+in order to specify definitely, although they walk on their fingers, as
+do the digitigrades, the support is provided not by the whole extent of
+those appendages, they might receive the name of phalangettigrades.
+
+[Illustration: FIG. 23.--THE HUMAN HAND RESTING ON ITS PHALANGES: LEFT
+SIDE, EXTERNAL SURFACE.]
+
+[Illustration: FIG. 24.--THE HUMAN HAND RESTING ON THE TIPS OF SOME OF
+ITS THIRD PHALANGES: LEFT SIDE, EXTERNAL VIEW.]
+
+It is necessary among the ruminants to make an exception of the camel
+and the llama, which are digitigrades.
+
+Just in proportion as the hand is raised from the ground, as we have
+just seen in passing from the plantigrades to the digitigrades and
+unguligrades, the number of bones of that region diminishes, the bones
+of the forearm coalesce, and the ulna tends to disappear; the hand
+becomes less and less suitable for grasping, climbing, or digging, so as
+to form an organ exclusively adapted for walking and supporting the
+body.
+
+Thus, the bear (plantigrade) has five digits, and the power of
+performing the movements of supination and pronation. Indeed, we know
+with what facility this animal is able to move his paws in every
+direction, and climb a tree by grasping it with his fore-limbs. It is
+well known, however, that no animal except the ape can perform the
+movements of rotation of the radius around the ulna with the same
+facility as man; and that none possesses the same degree of suppleness,
+extent, and variety of movements of the forearm and hand.
+
+In the digitigrades there is one finger which is but slightly developed,
+and which is always removed from the ground--that is, the thumb: there
+is also a little less mobility of the radius around the ulna.
+
+In the ungulates the limbs are simply required to perform the movements
+of walking, and form veritable columns of support, which become the more
+solid as they are less divided. The bones of the forearm are fused
+together; there is therefore no possibility of rotation of the radius
+around the ulna. The metacarpus is reduced to a single piece, which in
+the horse constitutes what is known as the _canon_. The number of digits
+becomes diminished, so that in ruminants there are not more than two,
+and in the horse but one. We should, however, add that, up to the
+present, we have taken into account only perfect digits, those that rest
+on the ground. We shall see further on that there exist supplementary
+digits, but that they are only slightly developed, and are represented
+in some cases by mere osseous spurs; it is this fact that has permitted
+us to ignore them in the general study which we have just made.
+
+Because, as we have already said, the unguligrades have the inferior
+extremity of the digit encased in a horny sheath, which forms the hoof
+of the horse and the corresponding structures (_onglons_) in the ox,
+those animals have been placed in a special group, which is based on
+that peculiarity--that is, the group of ungulate mammals.
+
+The plantigrades and digitigrades, of which the paws have their surfaces
+of support strengthened by an epidermic sole and fatty pads, have the
+free extremities of the third phalanges covered on their dorsal surface
+by nails or claws; hence they are named _unguiculate_ mammals.
+
+The bat and birds have the bones of the forearm so arranged that the
+radius cannot rotate around the ulna. This is necessary in order that
+during flight, when the wing is being lowered, the radius and hand shall
+not be able to turn; for, if such rotation took place, each stroke of
+the wing would place it in a vertical position, which would occasion a
+loss of resistance incompatible with the effect to be obtained.
+
+
+The Forearm
+
+The skeleton of the forearm in quadrupeds is vertical in direction;
+consequently, it forms with the arm an angle open anteriorly; this is
+well seen on examining the lateral surface. If we examine it on its
+anterior surface, we find a slight obliquity directed downwards and
+inwards. In animals in which the bones of the forearm are separate--that
+is to say, susceptible of supination and pronation--we find a more close
+resemblance to those of the human skeleton. The ulna, the superior
+extremity of which always projects beyond that of the radius, has a
+shaft which gradually narrows from above downwards. Its inferior
+extremity is terminated by a round head in those animals in which the
+ulna is fully developed; in others, as it is atrophied, it ends in a
+thin, long process.
+
+The ulna presents at its superior extremity a posterior process, the
+olecranon, which forms the point of the elbow. We find on the anterior
+surface of the same, another process, the coronoid.
+
+It is necessary to dwell on the relations of these parts. In man the
+head of the radius is situated at the anterior part of the external
+surface of the superior extremity of the ulna (Fig. 25); indeed, the
+small sigmoid cavity with which the head articulates is situated on the
+outer side of the coronoid process, and this apophysis is placed in
+front. In the plantigrades and digitigrades the head of the radius is
+placed still more forward, so much so that it is situated almost in
+front of the superior extremity of the ulna (Fig. 26). In the
+unguligrades it is placed directly in front of this latter (Fig. 27).
+
+Further, the displacement of the radius is made at the expense of the
+superior extremity of the neighbouring bone; the radius appears to
+appropriate more and more the parts which in man belong exclusively to
+the ulna--for example, the coronoid process. In the plantigrades and the
+digitigrades half of the process still belongs to the ulna and the
+remainder to the radius. In the ungulates--the horse, for example--the
+coronoid process belongs to the radius; the ulna, situated behind the
+latter, is correspondingly diminished in size.
+
+[Illustration: FIG. 25.--SUPERIOR EXTREMITY OF THE BONES OF THE HUMAN
+FOREARM: LEFT SIDE, SUPERIOR SURFACE.
+
+1, Radius; 2, ulna; 3, olecranon process; 4, coronoid process.]
+
+[Illustration: FIG. 26.--SUPERIOR EXTREMITY OF THE BONES OF THE FOREARM
+OF THE DOG: LEFT LIMB, SUPERIOR SURFACE.
+
+1, Radius; 2, ulna; 3, olecranon process; 4, coronoid process.]
+
+In brief, when we study this region of the skeleton in plantigrades,
+then in digitigrades, and finally in unguligrades, we find a kind of
+progressive absorption of one of the two bones (ulna) by the other
+(radius), which thus becomes the more developed.
+
+It is easy to explain this partial disappearance of the ulna. When the
+forearm is capable of performing the movements of pronation and
+supination, the ulna is completely developed, for it is in its small
+sigmoid cavity that the head of the radius revolves, and it is around
+its inferior extremity, the head, that the corresponding extremity of
+the radius turns. But when the movements of rotation of the forearm do
+not exist, the inferior extremity of the ulna becomes functionally
+useless and disappears. As to its rôle in the movements of the region of
+the wrist, that is nil, for we may remember--we will observe it again
+when we come to treat of the articulations--that the hand articulates
+with the radius alone (radio-carpal articulation); this is the reason
+that, when the forearm possesses the fullest mobility, the hand follows
+the movements which that bone makes around the ulna.
+
+[Illustration: FIG. 27.--SUPERIOR EXTREMITY OF THE BONES OF THE FOREARM
+OF THE HORSE: LEFT LIMB, SUPERIOR SURFACE.
+
+1, Radius; 2, ulna; 3, olecranon process; 4, coronoid process.]
+
+It is not so with the articulation at the elbow-joint; there it is the
+ulna, which, with the humerus, forms the essential parts (humero-ulnar
+articulation); its olecranon process limits the movement of extension
+of the forearm. It is for this reason that, even in those quadrupeds in
+which the ulna is atrophied, the olecranon process presents a relatively
+considerable degree of development.
+
+[Illustration: FIG. 28.--INFERIOR EXTREMITY OF THE BONES OF THE FOREARM
+OF A MAN: LEFT SIDE, POSTERIOR SURFACE, POSITION OF SUPINATION.
+
+1, Radius; 2, ulna; A, groove for the long abductor and short extensor
+muscles of the thumb; B, groove for the radial muscles; C, groove for
+the long extensor of the thumb; D, groove for the special extensor of
+the index finger and of the common extensor of the fingers; E, groove
+for the proper extensor of the little finger; F, groove for the
+posterior ulna.]
+
+[Illustration: FIG. 29.--INFERIOR EXTREMITY OF THE BONES OF THE FOREARM
+OF THE DOG: LEFT SIDE, ANTERIOR SURFACE, NORMAL POSITION--THAT IS, THE
+POSITION OF PRONATION.
+
+1, Radius; 2, ulna; A, groove for the long abductor and for the short
+extensor of the thumb; B, groove for the radials; D, groove for the long
+extensor of the thumb, the special extensor of the index-finger, and the
+common extensor of the fingers; E, groove for the special extensor of
+the little finger.]
+
+We know that on the posterior surface of the inferior extremity of the
+bones of the human forearm are grooves in which pass the tendons of the
+posterior and external muscles which, belonging to this region, are
+directed for insertion towards the hand.
+
+In animals, because of the movement of rotation of the radius, the
+surface of this bone, which is anterior, corresponds to the posterior
+surface of the same in man. (To possess a clear conception of this, it
+is necessary to remember that, in this latter, the bones of the forearm
+are always described as in the position of supination; they are thus
+represented in Fig. 28. The direction of the surfaces of the radius is
+the reverse of that in animals, since the latter have the radius always
+in a state of pronation.)
+
+Consequently it is on the anterior surface of the bone that we find the
+grooves concerning which it is necessary to give some details. Regarding
+them in passing from the radius towards the ulna, those grooves give
+passage to the tendons of the muscles whose names occupy the columns on
+p. 43. The letters which are referred to each serve to define their
+order, and to facilitate reference to Figs. 28, 29, and 30.
+
+[Illustration: FIG. 30.--INFERIOR EXTREMITY OF THE BONE OF THE FOREARM
+OF THE HORSE: LEFT SIDE, ANTERIOR SURFACE.
+
+1, Radius; A, groove for the long abductor and the short extensor of the
+thumb; B, groove for the radials; D, groove for the common extensor of
+the digits; E, groove for the special extensor of the little finger.]
+
+We should mention that the groove E is situated, both in man and in the
+dog, at the level of the inferior radio-ulnar articulation; but that in
+the horse, as the ulna does not exist at that level, the groove is
+situated on the external surface of the inferior extremity of the
+radius. It is necessary to add that, in some horses, the ulna is,
+nevertheless, represented in this region by a tongue-like process of
+bone; and in such cases the groove is situated in front of this process,
+at the level of the line of coalescence, which there represents the
+articulation.
+
+  -----------------------+-----------------------+-----------------------
+           MAN.          |          DOG.         |         HORSE.
+  -----------------------+-----------------------+-----------------------
+  A. Long abductor of the|A. Long abductor of the|A. _Oblique extensor of
+     of the thumb, and   |   thumb and short     |   the metacarpus_, the
+     short extensor of   |   extensor of the     |   homologue of the
+     the  thumb.         |   thumb united as one |   long abductor of the
+                         |   muscle, _the oblique|   thumb and the short
+                         |   extensor of the     |   extensor of the
+                         |   metacarpus_.[11]    |   thumb, united as one
+                         |                       |   muscle.
+                         |                       |
+  B. First and second    |B. The two radials     |B. The radials
+     external radials    |   blended superiorly, |   represented by a
+     (_extensor carpi    |   distinct inferiorly;|   single muscle, _the
+     radialis longior_   |   this is _the        |   anterior extensor of
+     and _brevior_).     |   anterior extensor of|   the metacarpus_.
+                         |   the metacarpus_.    |
+                         |                       |
+  C. Long extensor of the|C. Long extensor of the|C. The long extensor of
+     thumb.              |   thumb and special   |   the thumb and the
+                         |   extensor of the     |   special extensor of
+                         |   index finger united |   the index are
+                         |   superiorly. These   |   absent.
+                         |   muscles pass in the |
+                         |   following groove.   |
+                         |                       |
+  D. Special extensor of |D. Common extensor of  |D. _Anterior extensor
+     the index finger and|   the digits and the  |   of the phalanges_,
+     the common extensor |   two preceding       |   the homologue of the
+     of the fingers.     |   muscles.            |   common extensor of
+                         |                       |   the digits.
+                         |                       |
+  E. Special extensor of |E. _Extensor of the    |E. Lateral extensor of
+     the little finger.  |   third, fourth, and  |   the phalanges, the
+                         |   fifth digits_, or   |   homologue of the
+                         |   _the lateral        |   special extensor of
+                         |   extensor of the     |   the little finger.
+                         |   digits_, the        |
+                         |   homologue of the    |
+                         |   special extensor of |
+                         |   the little finger.  |
+                         |                       |
+  F. The posterior ulnar |There does not exist on the forearm a groove
+     (_extensor carpi    |for the posterior ulnar muscle, or _external
+     ulnaris_).          |flexor of the metacarpus_.
+  -----------------------+-----------------------------------------------
+
+  [11] The words printed in italics are the names used in veterinary
+       anatomy.
+
+It is also useful to note, with reference to the groove F, in which
+passes, in man, the tendon of the posterior ulnar muscle, that, when the
+forearm is in pronation, the radius alone being displaced, we can only
+see this groove on the surface which looks backwards; and that it is
+then separated from the groove which contains the tendon of the special
+extensor of the little finger by an interval equal to the thickness of
+the head of the ulna.[12] When the forearm is supinated, the two grooves
+are found, on the other hand, one beside the other: and the tendons
+which they contain are very naturally in contact.
+
+  [12] Édouard Cuyer, 'Shape of the Region of the Wrist in Supination
+       and Pronation' (_Bulletin de la Société d'Anthropologie_, Paris,
+       1888).
+
+In birds the forearm is flexed on the arm, and the latter being directed
+downwards and backwards, the former is, consequently, directed upwards
+and forwards. Further, because of the position of the humerus, which, as
+we mentioned on p. 32, has its inferior extremity so turned that the
+surface which is anterior in man becomes external, the radius, instead
+of being outside the ulna, is placed above it. This latter is larger
+than the radius, but its olecranon process is very slightly developed.
+
+
+The Hand
+
+The hand in animals, as in man, is formed of three parts--the carpus,
+metacarpus, and fingers. In man, the forearm and the hand being
+described in the position of supination; the bones of the carpus are
+named in passing from the most external to the most internal--that is to
+say, from that which corresponds to the radial side of the forearm to
+that which corresponds to the ulnar side. In animals in which, as we
+know, but it is not unprofitable to repeat, the hand is in pronation,
+the radial side of the forearm being placed inside, we enumerate the
+carpal bones in counting the most internal as the first; this is the
+only method which permits us, in taking our point of departure from the
+human skeleton as our standard, to recognise the homologies of the bones
+of the carpal region.
+
+These bones, eight in number, are arranged in two transverse rows, of
+which one, the first, is superior or antibrachial; the other, the
+second, is inferior or metacarpal. Each of these rows contains four
+bones. Considered in the order we have indicated above--that is to say,
+proceeding from the radial to the ulnar side--they are thus named:
+scaphoid, semilunar, cuneiform, and pisiform, in the first row;
+trapezium, trapezoid, os magnum, and unciform, in the second. The number
+of these bones is not the same in all animals on account of the
+coalescence or absence of some. In each row the bones are placed side by
+side, with the exception of the pisiform, which being placed on the
+palmar surface of the cuneiform, produces a small projection in man, but
+a very pronounced one in quadrupeds.
+
+The pisiform is called the _hooked bone_ in some veterinary anatomies.
+If we consider the hook which it forms, we may recognise that the name
+is appropriate; but from the point of view of comparison with the human
+carpus, the name is unfortunate, for it creates confusion between the
+true pisiform (the fourth bone in the upper row), and the last bone in
+the lower row, which is the veritable unciform bone. We do not here seek
+for similarity of form, but homology of regions; and it is only by using
+the same names to denote the same things that we can succeed in
+determining such homology.
+
+Taken as a whole, the bones of the carpus form a mass which, by its
+superior border, articulates with the bones of the forearm, and by its
+inferior border is in relation with the metacarpal region. Its dorsal
+surface (anterior in quadrupeds) is slightly convex; its palmar surface
+(posterior in quadrupeds) is excavated, and forms a groove in which pass
+the tendons of the flexors of the fingers. This last, in man, has the
+appearance of a gutter, because of the prominences caused by the
+projection of the internal and external bones beyond their fellows.
+
+In quadrupeds the palmar groove is especially determined by the pisiform
+bone, of which we have just mentioned the great development.
+
+The region occupied by the carpus, in the unguligrades, is known as the
+_knee_; it would have been more appropriately named had it been called
+the _wrist_.
+
+The number of the metacarpal bones in mammals never exceeds five, but it
+often falls below it; the same is true for the digits. The first are
+generally equal in number to the latter; an exception is met with in
+ruminants, whose two metacarpals coalescing soon after birth, form but
+one bone; this, the _canon_ bone, articulates with two digits.
+
+The number of metacarpals and digits diminishes in proportion as the
+limbs cease to be organs of prehension, and become more exclusively
+organs of support and locomotion.
+
+The number of phalanges is two for the thumb and three for each of the
+other digits; except in the cetaceans, in which they are more numerous.
+
+In the bat, the metacarpals and phalanges are very long, and form the
+skeleton of the wing; these phalanges are not furnished with nails; the
+thumb, which is very short, is alone provided with one (Fig. 8).
+
+With regard to the relative dimensions of the bones of the metacarpus,
+it is necessary to remember that, in the human being, the second
+metacarpal is the longest; then, in the order of decrease, come the
+third, fourth, fifth, and first. In quadrupeds we shall also find
+differences in length (see the chapter relating to the anterior limbs in
+certain animals), but the order of decrease is not always that which we
+have just mentioned.
+
+In man the articular surface, situated at the inferior extremity of each
+of the metacarpals, is rounded, and is called the head. This allows the
+first phalanx, which is in relation with that surface, to be displaced
+in every direction; indeed, this phalanx can not only be flexed and
+extended, but it can also be moved laterally; this latter movement
+allows of the fingers being separated and drawn together.
+
+In quadrupeds which can only perform the movements of flexion and
+extension of the digits--for example, the horse--the inferior extremity
+of the metacarpal has not a rounded head of a regular outline; it is
+marked by a prominent median crest, directed from before backwards, so
+that the articular surfaces, which fit more exactly, form a sort of
+hinge which allows of backward and forward movements only, and permits
+no lateral displacement. In man, at the level of the inferior extremity
+of the first metacarpal, in the vicinity of the articulation of this
+bone with the first phalanx of the thumb, we find two sesamoid
+bones--small bones developed in the fibrous tissue which surrounds the
+articulation. We also meet with such structures, but more rarely, at the
+level of the corresponding articulation of the index and auricular
+digits; and, more rarely still, at those of the middle and ring fingers.
+In quadrupeds, these bones are normally developed, and we shall see
+afterwards that in some animals, as they reach a considerable size, they
+are able to influence the external outlines; we shall see this, for
+example, in the horse.
+
+The hand, in birds, is directed obliquely downwards and backwards (Fig.
+31). For the better understanding of its position in relation to the
+forearm, we should remember that this latter, as we have described (p.
+44), directed obliquely upwards and forwards, has the radius placed
+above the ulna; the hand being oblique in the opposite direction and
+placed under the forearm is, by this arrangement, inclined towards the
+ulnar border of the latter.
+
+[Illustration: FIG. 31.--SKELETON OF THE SUPERIOR LIMB OF A BIRD
+(VULTURE): LEFT SIDE, EXTERNAL SURFACE.
+
+1, Humerus; 2, radius; 3, ulna; 4, radial bone of the carpus; 5, ulnar
+bone of the carpus; 6, first metacarpal; 7, second metacarpal; 8, third
+metacarpal; 9, first digit, the homologue of the thumb; 10, first
+phalanx of the second digit; 11, second phalanx of the second digit; 12,
+third digit.]
+
+For the rest, in order to be able to distinguish readily the
+corresponding parts in the hand of a bird and that of a man, we merely
+have to place the human forearm obliquely, in a direction upwards and
+forwards (Fig. 32), the radius being above; this position we can obtain
+by semi-pronation; then, to incline strongly the hand downwards and
+backwards, moving the ulnar border of the hand towards the ulna; the
+thumb is then anterior, the little finger posterior, and the palm of the
+hand is turned towards the trunk.
+
+The carpus in birds is formed by two bones only, with which the skeleton
+of the forearm articulates. That which is in contact with the radius is
+called the _radial bone of the carpus_; and that with which the ulna
+articulates is named the _ulnar bone_.
+
+[Illustration: FIG. 32.--SUPERIOR LIMB OF THE HUMAN BEING, THE DIFFERENT
+SEGMENTS BEING PLACED IN THE ATTITUDE WHICH THE CORRESPONDING PARTS
+OCCUPY IN BIRDS: LEFT SIDE, EXTERNAL SURFACE.]
+
+The metacarpus is formed of three bones; the first, which is very short,
+is fused at its superior extremity with the adjoining one; this latter
+and the third, both longer than the first, but of unequal size, are
+fused at their extremities. The metacarpal, which articulates with the
+radial bone of the carpus, is larger than the one which is in line with
+the ulna. To the metacarpus succeed three digits, of which the central
+is the longest, and is formed of two phalanges; the other two are formed
+each by a small, stylet-shaped bone. The middle finger, situated on the
+prolongation of the metacarpal, which articulates with the radial bone
+of the carpus, has its first phalanx large and flattened transversely;
+this phalanx seems to have been formed by the union of two bones of
+unequal development; the second phalanx is styloid in form. As to the
+other two fingers, they are placed, one in front and the other behind;
+the first, which articulates with the short metacarpal, fused at its
+upper end with the principal bone of the metacarpus, in position
+represents the thumb. The other, which is the third finger, articulates
+with the inferior extremity of the thinnest bone of the metacarpus; it
+is sometimes closely united to the corresponding border of the first
+phalanx of the large--that is to say, of the median--digit.
+
+
+The Anterior Limbs in Certain Animals
+
+=Plantigrades=: =Bear= (Fig. 33).--The scapula of the bear approaches in
+shape to a trapezium, of which the angles have been rounded off. The
+anterior border (cervical) is strongly convex in the part next the
+glenoid cavity. The junction of the superior (spinal) and the cervical
+border forms almost a right angle, the summit of which corresponds to
+the origin of the spine. At its posterior angle there is a prominence,
+directed downwards, the surface of which is hollowed and is separated
+from the infraspinous fossa by a crest, so that at this level a third
+fossa is added to the infraspinous one. The neck of the scapula is but
+slightly marked. The acromion is prominent, and projects a little beyond
+the glenoid cavity.
+
+The clavicle is rudimentary, but, as an example of the complete
+development of this bone in plantigrade quadrupeds, we may cite the
+marmoset.
+
+The humerus is furnished at its superior extremity with a large
+tuberosity, wide, and situated in front of the head of the bone; the
+effect of this is that the bicipital groove is internal. As in man, the
+great tuberosity does not reach so high as the humeral head, but it
+approaches more nearly to that level. The deltoid impression is very
+extensive, and descends pretty far down on the body of the bone. The
+epitrochlea is prominent; the epicondyle is surmounted by a well-marked
+crest, curved and flexuous in outline.
+
+[Illustration: FIG. 33.--SKELETON OF THE BEAR: LEFT LATERAL SURFACE.
+
+1. Cranium; 2, face; 3, atlas; 4, axis; 5, seventh cervical vertebra; 6,
+first dorsal vertebra; 7, fourteenth and last dorsal vertebra; 8, lumbar
+vertebræ; 9, sacrum; 10, coccygeal vertebræ; 11, sternum; 12, ninth and
+last sternal rib; 13, costal cartilages; 14, acromion process; 15, third
+fossa on the external surface of the scapula; 16, great tuberosity of
+the humerus; 17, musculo-spiral groove; 18, epicondyle; 19, radius; 20,
+ulna; 21, olecranon process; 22, carpus; 23, pisiform; 24, metacarpus;
+25, phalanges; 26, ilium, external fossa; 27, pubis; 28, tuberosity of
+the ischium; 29, obturator foramen; 30, great trochanter of the femur;
+31, condyles of the femur; 32, patella, or knee-cap; 33, anterior
+tuberosity of the tibia; 34, fibula; 35, tarsus; 36, calcaneum, or
+heel-bone; 37, metatarsus; 38, phalanges.]
+
+The articular surface, which is in contact with the radius, is not a
+regularly formed condyle; it is a little flattened on its anterior
+surface, and presents at this level a slight depression which
+corresponds to a small eminence on the anterior aspect of the superior
+extremity of the radius. The surface which articulates with the ulna,
+viewed on its anterior aspect, has the shape of a slightly-marked
+trochlea; except at the level of the internal lip, which, as in man,
+descends lower than the surface for articulation with the radius
+(condyle). Behind, the trochlea is more clearly defined.
+
+The bear possesses a considerable power of rotation of the radius; the
+bones of the forearm are joined only at their extremities, while in the
+remainder of their extent they are widely separated. The ulna terminates
+below in a head and a styloid process; these articulate with the two
+last bones of the first row of the carpus--viz., the cuneiform and
+pisiform. The bones of the carpus are seven in number, the scaphoid and
+the semilunar being fused together.
+
+The metacarpals, five in number, differ very little from one another in
+regard to length, though they increase in size from the first to the
+fifth; this may be demonstrated by looking at the palmar surface of the
+hand. It is the reverse of that which we find in man, for the fifth
+metacarpal is the thickest of all, and the first is the most slender.
+
+At the level of each metacarpo-phalangeal articulation are two sesamoid
+bones.
+
+The third digit is the longest. The terminal phalanges present two very
+different portions: one, the anterior, is curved and pointed; it serves
+to support the nail, whose shape it assumes; the other, posterior, forms
+a sort of sheath into which the base of the nail is received.
+
+The inferior portion of the posterior surface of this latter part
+articulates with the second phalanx in the case of each of the last four
+digits, but with the first phalanx in the case of the thumb.
+
+[Illustration: FIG. 34.--SKELETON OF THE DOG: LEFT LATERAL SURFACE.
+
+1, Cranium; 2, face; 3, atlas; 4, axis; 5, seventh cervical vertebra; 6,
+thirteenth and last dorsal vertebra; 7, lumbar vertebræ; 8, sacrum; 9,
+coccygeal vertebræ; 10, anterior extremity of the sternum; 11, xiphoid
+appendix; 12, ninth and last sternal rib; 13, costal cartilages; 14,
+spinal border of the scapula; 15, supraspinous fossa of the scapula; 16,
+infraspinous fossa of the scapula; 17, great tuberosity of the humerus;
+18, deltoid impression; 19, musculo-spiral groove; 20, olecranon
+process; 21, radius; 22, carpus; 23, pisiform; 24, metacarpus; 25,
+sesamoid bones; 26, phalanges; 27, ilium, iliac crest; 28, pubis; 29,
+tuberosity of the ischium; 30, great trochanter of the femur; 31,
+patella, or knee-cap; 32, anterior tuberosity of the tibia; 33, fibula;
+34, tarsus; 35, calcaneum, or heel-bone; 36, metatarsus; 37, sesamoid
+bones; 38, phalanges.]
+
+[Illustration: FIG. 35.--SCAPULA OF THE DOG: LEFT SIDE, EXTERNAL
+SURFACE.
+
+1, Posterior or axillary border; 2, superior or spinal border; 3,
+anterior or cervical border; 4, spine of scapula; 5, coracoid process;
+AA´, length of spinal border.]
+
+[Illustration: FIG. 36.--LEFT SCAPULA OF THE CAT: EXTERNAL SURFACE.
+
+1, Posterior or axillary border; 2, superior or spinal border; 3,
+anterior or cervical border; 4, spine of the scapula; 5, coracoid
+process; AA´, length of the spinal border.]
+
+=Digitigrades=: =Cat=, =Dog= (Fig. 34).--In these animals the anterior
+(cervical) border of the scapula is convex; the posterior (axillary)
+border is straight or slightly concave. The supraspinous and
+infraspinous fossæ are of equal extent (Figs. 35 and 36). The neck is
+short. The spine of the scapula becomes more and more prominent towards
+its inferior extremity, where it ends in a twisted and inflexed portion,
+which represents the acromion process; this process terminates at the
+level of the glenoid cavity. The coracoid process is represented by a
+small tubercle, slightly curved inwards; this tubercle is situated
+above the glenoid cavity, at the inferior part of the cervical border.
+
+In the dog, the posterior angle, formed by the junction of the axillary
+and the superior (spinal) borders, is obtuse; the spine rises
+perpendicularly from the surface of the bone. The width of the scapula,
+measured at the level of the spinal border (from A to A´, Fig. 35),
+equals about half the length of the spine. We must, however, make an
+exception for the turnspit dog, in which the superior border equals
+three-fourths of that length. The scapula is, in this case, of a more
+compact type; it is broader, but shorter. In the cat, the anterior
+outline of the scapula, formed by the union of the cervical border and
+the corresponding half of the spinal, is more convex; the posterior
+angle is not obtuse, as in the dog. The spine is bent slightly downwards
+and backwards; before terminating in the acromion process it presents a
+triangular projection, the apex of which is directed downwards. The
+tubercle which represents the coracoid process is curved inwards more
+strongly than that of the dog, thus resembling more closely the
+appearance of this process in the human being.
+
+All proportions considered, the scapula of the cat is broader than that
+of the dog; its width, measured along the length of its spinal border
+(from A to A´, Fig. 36), equals three-fourths of the length of the
+spine.
+
+The clavicle is rudimentary; it is, however, better developed in the cat
+than in the dog. The clavicle of the cat is represented by a small,
+elongated bone, curved in outline, the convexity being turned forward;
+it is united to the acromion and the sternum by ligamentous fibres; that
+of the dog is merely a scale-like osseous plate situated on the
+posterior surface of a muscle of this region (see Figs. 16 and 17).
+
+The humerus is long and twisted in the shape of an S. The inferior
+articular surface has the form of a simple pulley, for the condyle is
+very slightly marked. The internal part of this articular surface
+descends lower than the external; this condition resembles that found in
+the human being, where the inner lip of the trochlea is lower than the
+condyle.
+
+In the dog, the olecranon fossa communicates with the coronoid by an
+opening.
+
+In the cat, there is a supra-epitrochlear canal (see Fig. 19), but no
+olecranon perforation.
+
+The bones of the forearm articulate at their extremities. The body of
+the radius is united to the body of the ulna by a short, thick,
+interosseous ligament; the fibres of this ligament, though short, do not
+prevent the production of some movements at the articulations of the
+bones.
+
+The radius so crosses the ulna that above, it is in front and external
+to the latter, while below, it is internal. This bone is flattened from
+front to back, and slightly convex anteriorly. Its superior extremity is
+formed, externally, of a portion which represents the head of the radius
+in man; internally, by another portion which represents half of the
+coronoid process of the ulna, which, in the human being, belongs
+exclusively to the latter (see p. 39, the encroachment of the radius on
+the ulna). This extremity is surrounded with a vertical articular
+surface which is placed in contact with a small cavity which is hollowed
+out on the ulna (the lesser sigmoid cavity); and presents at its
+superior aspect a surface which articulates with the inferior extremity
+of the humerus. The shaft of the bone has on its internal border
+rugosities analogous to the imprint of the pronator radii teres of the
+human skeleton; these rugosities, indeed, give insertion to a muscle of
+the same function, and bearing the same name. The inferior extremity,
+broader than the superior, is hollowed on its external aspect by a small
+cavity which receives the inferior extremity of the ulna; its inferior
+surface (concave) articulates with the carpus; its anterior surface (the
+homologue of the posterior surface of the corresponding extremity of the
+human radius) presents grooves which serve for the passage of the
+tendons of the muscles which pass from the forearm to the back of the
+hand. (For the names of the muscles whose tendons pass in these grooves,
+see Fig. 29.)
+
+The ulna is furnished at its superior extremity with an olecranon
+process, which is more prominent than that of the human ulna; this
+process is compressed laterally, and its internal surface is hollowed;
+there we also find a great sigmoid cavity, and a coronoid process
+situated at the internal part of the anterior surface, a process which,
+as we have previously shown, it shares with the radius.
+
+The shaft of the bone, prismatic and triangular, diminishes in thickness
+as it approaches the lower extremity, which articulates with the
+corresponding extremity of the radius. In the dog, the ulna terminates
+inferiorly in a blunt point, without enlargement, analogous to the head
+of the human ulna; in the cat, by a head which is prolonged into a
+styloid process, by which it articulates with a portion of the carpus.
+
+The carpus consists of seven bones--three in the superior row and four
+in the inferior. In the superior row the scaphoid and semilunar bones
+are fused together. The pisiform is elongated and expanded at its two
+extremities; it forms a prominence which, directed backwards, projects
+beyond the level of the other bones of this region.
+
+The metacarpal bones are five in number; they are enumerated from within
+outwards; they articulate with the carpus and with each other. The
+inferior extremity of each metacarpal bone presents the form of a
+condyle in front; and is divided behind so as to form two lateral
+condyles, which are separated by a median crest; on these posterior
+condyles are applied two small sesamoid bones. The metacarpal bone of
+the thumb is very short; the third and fourth are the longest. The
+metacarpus, as a whole, is directed vertically.
+
+The phalanges are three in number for each finger, except the thumb,
+which has but two. The first phalanx, directed almost horizontally
+forwards, is the longest; the second is directed downwards and forwards;
+the third consists of two portions: a posterior part, which forms a sort
+of sheath into which the base of the nail is received; and an anterior,
+conical in form, and curved in crochet shape, which forms a support for
+the nail (Fig. 37).
+
+The third and fourth digits are the longest; the second and fifth are of
+equal length; the thumb is the shortest; it does not touch the ground,
+and does not even reach the articulation of the metacarpal bone and
+first phalanx of the second finger.
+
+In the cat, the metacarpal bone of the thumb, although shorter than any
+of the others, is quite as thick. The third digit is a little longer
+than either the second or fourth. In animals of this genus, the claws,
+in the condition of repose, are retracted, and removed from the ground;
+this prevents their being worn, and thus preserves their sharpness. At
+such times the third phalanx is received into a groove which is found on
+the external surface of the second phalanx. In the dog, the claws are
+not tractile.
+
+[Illustration: FIG. 37.--SKELETON OF THE FINGER OF A FELIDE (LION): LEFT
+SIDE, INTERNAL SURFACE.
+
+1, Metacarpus; 2, sesamoid bones; 3, first phalanx; 4, second phalanx;
+5, third phalanx; 6, gutter for the reception of the base of the nail;
+7, prominent osseous crest formed to lodge in the concavity of the
+nail.]
+
+[Illustration: FIG. 38.--SKELETON OF THE PIG: LEFT LATERAL SURFACE.
+
+1, Cranium; 2, face; 3, atlas; 4, axis; 5, seventh cervical vertebra; 6,
+first dorsal vertebra; 7, fourteenth and last dorsal vertebra; 8, lumbar
+vertebræ; 9, sacrum; 10, coccygeal vertebræ; 11, anterior extremity of
+the sternum; 12, xiphoid appendix; 13, seventh and last sternal rib; 14,
+costal cartilage; 15, cartilage of prolongation of the scapula; 16,
+great tuberosity of the humerus; 17, olecranon process; 18, radius; 19,
+ulna; 20, pisiform; 21, metacarpus; 22, phalanges of the two great toes;
+23, phalanges of the external toe; 24, ilium; 25, pubis; 26, tuberosity
+of the ischium; 27, great trochanter; 28, knee-cap; 29, anterior
+tuberosity of the tibia; 30, fibula; 31, tarsus; 32, calcaneum; 33,
+metatarsus; 34, phalanges of the two great toes; 35, phalanges of the
+external toe.]
+
+=Unguligrades=: =Pig= (Fig. 38).--The scapula is markedly narrowed in
+the region above the glenoid cavity. The spine is atrophied at both its
+extremities, so that at its inferior part we do not find the acromion
+process. In its middle portion the spine is prominent, and presents a
+triangular process which turns backwards, overlapping a part of the
+infraspinous fossa; this latter is much larger than the supraspinous.
+The spinal border is surmounted by the cartilage of prolongation, the
+superior margin of which is convex; this cartilage extends posteriorly
+beyond the posterior (axillary) border of the bone.
+
+The small tuberosity of the superior extremity of the humerus is but
+slightly developed; the great tuberosity, on the contrary, is very
+large. The bicipital groove is situated internal to this. The deltoid
+impression is scarcely marked.
+
+The forearm is short, directed obliquely downwards and inwards, thus
+forming with the hand an angle, of which the apex is directed inwards.
+The two bones of the forearm are strongly bound to one another by an
+interosseous ligament, which is formed of very short fibres. The radius
+appropriates, at its superior extremity, the coronoid process of the
+ulna. The latter is, notwithstanding, well developed in the rest of its
+extent; it has a flattened shaft which almost completely overlaps the
+posterior surface of the radius; its inferior extremity reaches to the
+carpus.
+
+The carpus is formed of eight bones--four in the superior row, and four
+in the inferior. The third bone of the superior row (cuneiform) is more
+in contact with the ulna than with the radius.
+
+There are but four metacarpal bones; there is no metacarpal of the
+thumb. The two median metacarpal bones are the longest; they are those
+which correspond to the digits which alone touch the ground. The
+internal digit and the external one are thin and short; they are
+functionless, as a rule, taking no part in supporting the limbs on the
+ground. Notwithstanding this, they are formed, as the other digits, of a
+number of phalanges, which give them the semblance of perfect digits.
+(We shall soon see that in certain animals there exist digits which,
+being incomplete with regard to the numbers of their constituent bones,
+more accurately merit the name of imperfect digits.)
+
+The third phalanges are each enclosed in a horny hoof, to which the name
+of _onglon_ has been given.
+
+We have already drawn attention to the smaller lateral digits, and
+noted the general fact that they do not come in contact with the ground.
+It is necessary to modify this statement by adding that under certain
+conditions they give a slight amount of support; for example, when the
+individual is the subject of excessive obesity, the limbs yield under
+the weight, and the nails of the lateral digits may touch the ground.
+
+A similar fact may be noticed in pigs of ordinary bulk at the moment
+when, during walking, each of the fore-limbs commences to bear the
+weight--that is to say, when it is directed obliquely downwards and
+forwards; then all the digits are in contact with the ground.
+
+=Unguligrades (Ungulates)=: =Sheep=, =Ox= (Fig. 39).--The scapula, which
+is of elongated form, is very narrow in the vicinity of the glenoid
+cavity. The spine, which becomes more and more salient towards its
+inferior part, terminates abruptly in a border, which, forming an acute
+angle with the crest, produces a projection which represents the
+acromion process--a very rudimentary acromion, for it does not reach the
+level of the glenoid cavity. The supraspinous fossa is much smaller than
+the infraspinous; it hardly equals one-third the extent of the latter.
+The anterior border, thin and convex in its superior portion, is concave
+in the rest of its extent; the posterior border is thick and slightly
+concave; the spinal border is surmounted by the cartilage of
+prolongation. In the ox the spine of the scapula, in its middle portion,
+is flexed a little backwards on the infraspinous fossa.
+
+[Illustration: FIG. 39.--SKELETON OF THE OX: LEFT LATERAL SURFACE.
+
+1, Cranium; 2, face; 3, atlas; 4, axis; 5, seventh cervical vertebra; 6,
+first dorsal vertebra; 7, thirteenth and last dorsal vertebra; 8, lumbar
+vertebræ; 9, sacrum; 10, coccygeal vertebræ; 11, sternum; 12, xiphoid
+appendix; 13, eighth and last sternal rib; 14, costal cartilages; 15,
+spine of scapula; 16, cartilage of prolongation of the scapula; 17,
+great tuberosity of the humerus; 18, musculo-spiral groove; 19,
+olecranon process; 20, radius; 21, carpus; 22, pisiform; 23, metacarpus;
+24, rudimentary metacarpal; 25, sesamoid bones; 26, first phalanges; 27,
+second phalanges; 28, third phalanges; 29, anterior iliac spine; 30,
+pubis; 31, tuberosity of the ischium; 32, great trochanter; 33,
+supracondyloid fossa of the femur; 34, patella, or knee-cap; 35,
+anterior tuberosity of the tibia; 36, fibula; 37, coronoid tarsal bone;
+38, tarsus; 39, calcaneum; 40, metatarsus; 41, rudimentary metatarsus;
+42, sesamoid bones; 43, first phalanges; 44, second phalanges; 45, third
+phalanges.]
+
+The great tuberosity of the humerus is highly developed; its summit,
+very prominent, is flexed over the bicipital groove; a prominence of the
+small tuberosity also bends over the groove, with the result that at
+this level the latter is converted into a sort of canal. At the inferior
+extremity the condyle, although not large, is recognisable; for it is
+separated from the trochlea by a depression in form of a groove. In
+contrast to the condition found in man, the condyle descends to a level
+a little below that of the internal lip of the trochlea. (For the
+arrangement of the epicondyle and the epitrochlea, see p. 30.) In the
+sheep, the deltoid impression is but slightly marked; in the ox, it is
+more evident.
+
+The forearm is directed obliquely downwards and inwards, so as to form,
+with the hand, an angle of which the apex is internal; this angular
+outline of the _knee_ (wrist) is so characteristic of ruminants that the
+corresponding region of the horse, when salient inwards, receives the
+name of _ox-knee_. The radius bears the coronoid process, and the larger
+part of the articular surface which comes in contact with the inferior
+extremity of the humerus; the condyle and the trochlea articulate with
+the radius in front; while behind, the trochlea articulates with that
+part of the sigmoid cavity which belongs to the ulna. The posterior
+surface of the shaft of the radius is flattened; its anterior surface is
+slightly convex. The inferior extremity articulates with the carpus by a
+surface which is directed obliquely downwards and inwards. The shaft of
+the ulna is very slender, and fused in its middle third with the body of
+the radius; it terminates below, at the level of the external part of
+the inferior extremity of the radius, by a slightly expanded portion
+which, fused with this latter, forms the articular surface for the
+carpal bones.
+
+In the ox the forearm is short; in the sheep it is proportionally
+longer.
+
+The bones of the carpus are six in number--four in the upper row, and
+two in the lower; they form an irregular cuboid mass which contributes
+to the formation of the region known as _the knee_ in ruminants, as in
+the horse; we have already remarked that the name 'wrist' would be more
+accurate. The anterior surface in its foremost part is vertical, and is
+slightly convex from side to side. At its posterior and external part
+the pisiform bone forms a prominence.
+
+The metacarpus consists of two bones only--one, well developed, which is
+known as the principal metacarpal, or the _canon_ bone (this is the name
+given to the region in the hoofed animals); and a rudimentary one, which
+is situated at the superior and external aspect of the preceding
+metacarpal. Sometimes there is found a third metacarpal at the internal
+aspect; but, when present, it is but very slightly developed.
+
+The principal metacarpal consists of two metacarpals fused together; on
+this account the bone is longitudinally marked in the median line by a
+slight depression which marks the junction of the two bones of which it
+is formed. In some ruminants (certain species of chevrotains) the
+coalescence does not take place, and the two metacarpals remain
+separate.
+
+The anterior surface of the principal metacarpal is convex transversely;
+its posterior surface is flattened. The superior extremity of this bone
+articulates by two facets with the two bones of the inferior row of the
+carpus; on the internal part of the anterior surface of this extremity
+is found a tubercle. The inferior extremity is divided into two parts by
+a fissure or notch; each part is articular, and consists of two separate
+condyles, which are separated from each other by an antero-posterior
+crest; on each side of this crest, and behind, are found two sesamoid
+bones. As for the external rudimentary metacarpal bone, it is nothing
+more than a small, short tongue of bone; which, in goats and sheep, is
+often absent.
+
+The division of the inferior extremity of the principal metacarpal into
+two parts is correlated with the two perfect digits which give the foot
+of the ruminant its forked appearance. Each digit consists of three
+phalanges, which are directed obliquely downwards and forwards; further,
+these phalanges are inclined a little outwards from the axis of the
+limb, so that the two digits diverge from each other as they descend.
+
+The first phalanx, which is the longest, articulates superiorly with the
+principal metacarpal; its inferior extremity terminates in a trochlea,
+and the lip of this, which is situated towards the axis of the limb,
+descends lower than that of the opposite side; this arrangement is
+correlated with the divergent direction of the digits. The second
+phalanx has its superior extremity moulded on the trochlea which
+terminates the extremity of the first; its inferior extremity is
+articular, and elongated from before backwards. On the posterior
+surface of this extremity is found a sesamoid bone.
+
+With regard to the third phalanx, it presents the form of a triangular
+pyramid, and displays a postero-superior concave surface with which the
+second phalanx articulates; an anterior, convex surface, which
+terminates in a point on its anterior part; and an internal surface,
+which is flattened. The third phalanx of each digit is contained in a
+hoof (_onglon_).
+
+There is also found in ruminants two imperfect rudimentary digits, which
+are represented by two small bones situated behind the articulation of
+the metacarpal and the digits which we have just been studying. These
+rudimentary digits are each enveloped in a layer of horn; they
+constitute the _spurs_. The two digits of the ruminants represent the
+third and fourth fingers of the human hand; the two lateral digits,
+greatly atrophied, are the homologues of the second and fifth fingers;
+the thumb is not present.
+
+It is the same as regards the metacarpal bones, which form, by their
+union, the principal metacarpal; the external represents the fourth
+metacarpal, and the internal the third. It is to the latter that the
+tubercle, of which we have already made mention, belongs; and with the
+signification of which, because it gives attachment to a muscle, we
+shall concern ourselves in the section on myology (see Radial Muscles).
+
+=Unguligrades=: =Horse= (Fig. 40).--The scapula is narrow, compared with
+that of the animals we have just been considering. The anterior border
+is convex in its superior portion, and concave in its inferior; the
+posterior border is slightly hollowed out. The supraspinous fossa is
+less in extent than the infraspinous; but the difference is less
+than that between the same fossæ in the ox and the sheep; in the
+ox, as we have already indicated, the proportion is one-third; in
+the horse, one-half. The spine, which disappears at the extremities,
+is rough and thick in its middle third, there forming a kind of
+tuberosity--_tuberosity of the spine_. Above and in front of the glenoid
+cavity is found a strong process consisting of a rugous base, and a
+summit which is directed inwards. This forms a kind of hook curved
+towards the inside; it represents the coracoid process. The scapula is
+surmounted by the cartilage of prolongation, of which the superior
+border, which is thin and curved, is parallel to the superior border of
+the prominence of the withers; the cartilage forms, consequently, the
+lateral surface of this region. The cartilage of prolongation undergoes
+ossification in old horses. The humerus is short; the bicipital groove,
+situated on the anterior surface of the superior extremity, separates
+the greater tuberosity from the lesser, and is divided into two parts by
+a median ridge; it is this portion of the humerus which forms the
+prominence known as the _point of the shoulder_, or _point of the arm_.
+The deltoid impression well deserves the name of tuberosity which has
+been given to it, for it is very prominent; the musculo-spiral groove is
+very deep.
+
+[Illustration: FIG. 40.--SKELETON OF THE HORSE: LEFT LATERAL SURFACE.
+
+1, Cranium; 2, face; 3, atlas; 4, axis; 5, seventh cervical vertebra; 6,
+first dorsal vertebra; 7, eighteenth and last dorsal vertebra; 8, lumbar
+vertebræ; 9, sacrum; 10, coccygeal vertebræ; 11, sternum; 12, xiphoid
+appendix; 13, eighteenth and last sternal rib; 14, costal cartilage; 15,
+scapula; 16, cartilage of extension; 17, great tuberosity of the
+humerus; 18, deltoid crest; 19, olecranon process; 20, radius; 21,
+carpus; 22, pisiform; 23, principal metacarpal; 24, metacarpal,
+external rudimentary; 25, large sesamoids; 26, first phalanx; 27,
+second phalanx; 28, third phalanx; 29, ilium, showing external iliac
+fossa; 30, pubis; 31, tuberosity of the ischium; 32, great trochanter;
+33, infratrochanteric crest, or third trochanter; 34, supracondyloid
+fossa of the femur; 35, knee-cap; 36, anterior tuberosity of the tibia;
+37, the fibula; 38, tarsus astragalus; 39, calcaneum; 40, principal
+metatarsal; 41, rudimentary external metatarsal; 42, large sesamoids;
+43, first phalanx; 44, second phalanx; 45, third phalanx.
+
+_To face p. 64._]
+
+At the inferior extremity, the trochlea is large; the portion
+corresponding to the condyle of the humerus in man is, in proportion to
+the latter, of small extent. The olecranon fossa is deep. The epicondyle
+and the epitrochlea are somewhat different from those of the human bone.
+In the latter, the epitrochlea is salient towards the inner side,
+causing an increased transverse diameter of the inferior extremity of
+the humerus. In the horse--it is the same in ruminants--this tuberosity
+projects backwards, folds on itself in forming the internal boundary of
+the olecranon cavity, and exceeds in diameter, in the antero-posterior
+direction, the prominence of the epicondyle, which presents a nearly
+similar arrangement. This latter has, however, a part which, projecting
+externally, is situated at the inferior part of a crest, that forms the
+posterior boundary of the musculo-spiral groove. The result is that,
+contrary to the condition found in the human being, the epicondyle is
+more prominent transversely than the epitrochlea, but this latter is
+more salient on the posterior aspect. The epitrochlea and the epicondyle
+offer a larger surface for the origin of muscles of the forearm than the
+same prominences in the human bone do for the analogous muscles of the
+same region.
+
+Some veterinary anatomists have given to the inferior and external
+articular surface of the humerus the name of trochlea; and to the
+internal one, that of condyle. On this account they designate the
+external prominence as the epitrochlea, and the internal one as the
+epicondyle. In addition to the fact that this point of view is not
+legitimate, it produces inevitable confusion when comparing the parts
+with those of the human humerus, and this confusion exists, not alone in
+describing the bone, but also in the description of the muscular
+attachments, and in the comparison of the muscles of the forearm of
+quadrupeds with the corresponding muscles in the human species.
+
+The radius is placed in front of the ulna; its body, slightly convex
+forwards, has the anterior surface convex transversely, and the
+posterior surface plane in the same direction. It is to the external
+part of this latter that the ulna is applied, which is completely fused
+with the radius.
+
+The superior extremity of the radius is a little larger than the
+inferior. Its superior aspect, concavo-convex, moulded on the inferior
+articular surface of the humerus, presents internally two cavities,
+which receive the lips of the trochlea, and, externally, another,
+smaller, cavity, which receives the condyle. The radius articulates with
+the trochlea and the condyle, having appropriated a portion of the ulna,
+as is proved by the presence of the coronoid process, which belongs to
+the former. This superior extremity presents, internally, a tuberosity
+into which the biceps is inserted; this is the bicipital tuberosity; and
+on the other side is another tuberosity, which is a little more
+prominent than the preceding.
+
+The inferior extremity, which is flattened from before backwards, is
+furrowed on its anterior surface by grooves for the passage of muscles
+(the names of the muscles whose tendons pass in these grooves have
+already been given on p. 43). It articulates at the lower end with the
+superior row of the carpus, and it terminates laterally in tuberosities:
+one, external, on which is found a groove for the tendon of the lateral
+extensor of the phalanges, the homologue of the special extensor of the
+little finger; the other, internal, is a little more prominent than the
+one we have just described. These tuberosities are visible under the
+skin which covers the superior and lateral parts of the region known as
+the _knee_; but which, we again repeat, is no other than the wrist.
+
+The ulna has a triangular shaft, situated at the posterior surface of
+the radius, with which it is fused. It disappears completely at the
+level of the inferior third of the forearm. Occasionally, in some
+horses, the ulna is abnormally long, in the form of a slender tongue of
+bone; and extends to the neighbourhood of the external tuberosity of the
+inferior extremity of the radius (see Fig. 79, p. 196). Its superior
+extremity is chiefly represented by the olecranon process, which is
+voluminous in bulk, and forms the projection known as the point of the
+elbow. This process is flattened laterally; its internal surface is
+excavated; the anterior surface, which is concave, forms a part of the
+great sigmoid cavity; the remainder of the cavity is formed by the
+radius.
+
+In the ass, the ulna is a little longer than in the horse--that is to
+say, it descends lower; and the radius is a little more convex
+anteriorly.
+
+The carpal bones are seven in number--four in the superior row, and
+three in the inferior. The trapezium is wanting in the latter.
+Sometimes, however, in certain varieties of horses the trapezium is
+developed, but then it is no more than a very small osseous nodule. The
+pisiform bone, situated at the external part of the first row of bone,
+is prominent posteriorly. It is of rounder form and flattened from
+without inwards. It articulates with the trapezium and the radius. It
+presents, on its external surface, a groove for the passage of the
+tendon of the posterior ulnar muscle, which is named by veterinary
+anatomists the _external flexor of the metacarpus_.
+
+The carpus, as a whole, is of an irregularly cuboid shape; its anterior
+surface, slightly convex from side to side, forms the skeleton of the
+region of the _knee_ (wrist). The metacarpus is formed of three bones:
+the principal metacarpal and the two rudimentary ones.
+
+The principal metacarpal, which forms the region of the _canon_, is
+directed vertically; its anterior surface is slightly convex
+transversely. This surface is covered by a number of tendons, which
+slightly alter its appearance; so that it is the principal base of this
+part of the fore-limb. Its posterior surface is flattened. The superior
+extremity of this metacarpal presents plane surfaces, variously
+inclined, with which the bones of the inferior row of the carpus
+articulate. On the anterior surface, and a little to the inner side, is
+found a tuberosity, which is destined for the insertion of _the anterior
+extensor of the metacarpus_, the homologue of the radial muscles. The
+inferior extremity is formed by two condyles, an internal and an
+external; between which is found a median crest.
+
+This extremity, the superior extremity of the first phalanx, which
+articulates with it, together with two sesamoid bones--the great
+sesamoids--which are situated on its posterior surface, collectively
+form the region which from its rounded outlines is called the _ball_.
+
+With regard to the rudimentary metacarpals, external and internal, to
+which some authors give the name of _fibulæ_, they are applied to the
+sides of the posterior surface of the principal metacarpal. They are
+elongated bones, of which the superior extremity, which is a little
+thickened, is called the _head_; the lateral bones of the second row of
+the carpus partly rest on the heads of these. They become more slender
+as they descend, and terminate opposite the inferior fourth of the
+principal metacarpal. Each ends in a slight swelling, to which the name
+_button_ has been given. The internal one is the better developed.
+
+The rudimentary metacarpals are vestiges of atrophied digits, as will be
+explained further on.
+
+The single finger of the horse consists of three phalanges. The first
+phalanx, which is directed obliquely downwards and forwards, corresponds
+to the constricted region situated below the 'ball,' and known as the
+_pastern_. It is flattened from before backwards; its anterior surface
+is convex transversely, while the posterior surface is plane. Its
+superior extremity is moulded on the inferior extremity of the principal
+metacarpal, and its inferior extremity, which is smaller, presents a
+trochlea with which the second phalanx articulates. This is also
+directed downwards and forwards, and is shorter. It corresponds to the
+region which, situated between the pastern and the hoof, is known as the
+_cornet_.
+
+The third phalanx, situated entirely within the hoof, has the same
+direction as the first and second. It is large and broad, and presents
+three surfaces separated by well-marked angular borders (see Fig. 96).
+The anterior surface is oblique downwards and forwards; it is convex
+transversely. The inferior surface is slightly hollowed, and is in
+relation with the sole, or plantar surface of the hoof.
+
+The superior surface, which is articular, is divided by a median ridge
+into two lateral cavities, which correspond to the trochlea on the
+inferior surface of the lower extremity of the second phalanx. The
+inferior border corresponds in shape with the hoof. The superior border
+presents in its median part a projection, _the pyramidal eminence_,
+which prolongs at this level the anterior surface of the bone. Finally,
+the posterior border, which is concave, is in contact with a sesamoid
+bone, _the lesser sesamoid_, which increases the superior articular
+surface behind, and is also in contact with the second phalanx.
+
+As we have just seen, the horse possesses but one digit. In the
+ancestors of the animal--that is, in the prehistoric species which
+are now extinct (_orohippus_, _miohippus_, _protohippus_, or
+_hipparion_)--the number of digits was larger; this fact conclusively
+proves that the rudimentary metacarpals of the existing horse are
+vestiges of digits which have disappeared through want of use. In the
+first of those ancestors--orohippus--there were four digits; all save
+the first, the thumb, being then developed. In the others of the series
+there existed but three digits. It must, however, be noted that in those
+animals it is always the digit which corresponds to the middle finger of
+the pentedactyl hand that is longest. In other less ancient species the
+lateral fingers are reduced to the condition of mere splints of bone. It
+follows from what has been said that the digit which persists in the
+equine species should be considered as the third finger, and that the
+rudimentary metacarpals represent lateral digits considerably
+atrophied.
+
+This disappearance of the lateral digits cannot excite surprise when we
+consider the functions of the organs. Becoming useless, they must
+undergo gradual atrophy from want of use.
+
+There undoubtedly is, in this former existence of supplementary digits
+in the horse, something analogous to what we still find in the pig;
+where the two principal digits are accompanied by two shorter ones,
+which very probably, from their infrequent use, are destined to
+disappear in a more or less distant future.
+
+
+Proportions of the Arm, the Forearm, and the Metacarpus
+
+As a supplement to the study of the anterior limbs which we have just
+finished, it appears necessary to give some indications of the relative
+proportions of certain of the segments which form these limbs in the
+plantigrades, the digitigrades, and the ungulates.
+
+First, we would remark that, in following this order of classification,
+the scapula becomes less and less narrow, and assumes a form more and
+more elongated. In order to convince ourselves of this, it will be
+sufficient to study the bone first in man, then in the bear, the cat,
+dog, ox, and finally in the horse.
+
+As to the proportions of length, which are those we should chiefly
+study, we shall commence with the comparison of the forearm and
+arm--that is to say, the radius and the humerus. The radius is found to
+be longer in proportion to the humerus, as the number of digits is
+smaller, and the hand loses more and more the functions of an organ of
+prehension. In man, the radius is shorter than the humerus; in the
+horse, on the contrary, it is longer.
+
+To give an idea of this proportion, we shall employ what is known as the
+antibrachial index. This index gives the relation which exists between
+the length of the forearm and that of the humerus; the length of this
+latter, whatever may be the actual measurement, is represented by a
+fixed figure, the number 100. A very simple arithmetical operation
+gives the proportion--
+
+  forearm × 100
+  -------------, the quotient obtained furnishes the index.
+     humerus
+
+The index is less than 100 if the forearm is shorter than the bone of
+the arm. The index is more than 100 if, on the contrary, the forearm is
+longer.
+
+In man, the radius is shorter than the humerus; indeed, in adult
+individuals of the white race the average index is 74.
+
+In the bear, the length of the radius approaches closely to that of the
+humerus; the index is about 90. In the skeleton of a bear in the
+anatomical museum of the École des Beaux-Arts, the humerus is 33
+centimetres in length, and the radius 30 centimetres.
+
+In the cat, the radius is very little shorter than the humerus. In the
+dog they are equal. The antibrachial index of the latter is,
+accordingly, 100.
+
+In the horse, the radius is longer than the humerus; the index is
+therefore above 100. Thus, in the skeleton of the horse which we have in
+the museum of the École des Beaux-Arts, the index is 113--length of
+humerus, 29 centimetres; length of radius, 33 centimetres. In other
+skeletons which we have measured we found: in one, 108--humerus, 34
+centimetres; radius, 37 centimetres; in another, 116--humerus, 25
+centimetres; radius, 29 centimetres.
+
+The metacarpal bone undergoes, relatively to the humerus, a proportional
+elongation, analogous to that of the forearm.
+
+In man, the length of the metacarpus is contained about 5-1/2 times in
+that of the humerus; in the bear, it is contained 4 times; in the dog,
+2-1/2 times; in the horse, 1-1/3 times only.
+
+It is well known that the proportions vary according to race, and that
+what we have here given are but the general indications.
+
+
+The Articulations of the Anterior Limbs
+
+The knowledge of human arthrology which we presume the reader to have
+previously acquired makes it unnecessary for us to enter into numerous
+details regarding the configuration of the articular osseous surfaces
+and the disposition of the fibrous bands that retain them in position.
+Accordingly, in the description which follows, and also in that of the
+articulations of the posterior limbs, we shall occupy ourselves but very
+briefly with the details above referred to, so as to devote ourselves
+especially to the indication of the movements--that is to say, of that
+which, while easily comprehended on recollection of former studies,
+presents the greatest interest from the artistic standpoint in these
+studies in comparative anatomy.
+
+=The Scapulo-Humeral Articulation.=--The head of the humerus and the
+glenoid cavity of the scapula being in contact, the two bones are bound
+together by a rather loose articular capsule, which is strengthened by
+the muscles of this region which fulfil the function of active
+ligaments.
+
+This articulation, so movable in every direction in the human species,
+is not so much so in quadrupeds; the arm in the latter, as also the
+shoulder, being kept in contact with the lateral region of the thorax by
+the numerous muscles which surround it.
+
+Of the movements performed by the humerus, flexion and extension are the
+most extensive; those of abduction and adduction are much less so.
+
+It is necessary, before proceeding further, to determine what the two
+principal movements which we have just mentioned really are, viz.,
+flexion and extension.
+
+We know that in man the displacements of the humerus which take place in
+the antero-posterior direction are known as movement or projection
+forwards, and movement or projection backwards, respectively. We do not
+say that the humerus is flexed or extended, because, in reality, on
+account of the position which the skeleton of the shoulder occupies, it
+is not able to flex or place itself on the line of prolongation of the
+scapula with which it articulates.
+
+In quadrupeds it is not so. The humerus and the scapula are contained in
+almost the same vertical plane; and the bone of the arm can take, in
+relation to the latter, the positions characteristic of flexion and
+extension--that is, of approach to the scapula and removal from it.
+
+What makes the meanings of these terms a little confusing is that, in
+human anatomy, some authors consider the backward movement of the
+humerus as extension, and the forward movement as flexion; in order to
+be able to compare these movements to those that the femur executes in
+relation to the pelvis.
+
+Now, in our opinion, the indication of this correspondence is not
+absolutely necessary; since it ceases to be exact if we wished, from the
+point of view of the direction given to other segments of the skeleton,
+to establish the same relation between the elbow and the articulation of
+the knee.
+
+It is therefore indispensable, when discussing quadrupeds, to
+discontinue these terms, in order the more readily to recognise that: in
+flexion the inferior extremity of the humerus is directed backwards; in
+extension, on the contrary, it is directed forwards. In the first case
+the humerus approaches the scapula; in the second, on the contrary, it
+moves away from it.
+
+These movements, which take place during walking, are executed in the
+following manner: When one of the anterior limbs is at the end of that
+stage of progression which is called support (see p. 289, Displacements
+of the Limbs)--that is to say, during the time that the foot remains in
+contact with the ground, whilst the trunk is moving forward--the
+direction of this limb becomes more and more oblique downwards and
+backwards. At a certain moment the limb is raised from the ground, to be
+carried forwards, in order to be again pressed on the ground, and
+recommence a new resting stage. In these different phases the humerus is
+flexed. But at the moment that the limb, when carried forwards, is about
+to resume its contact with the ground it becomes directed obliquely
+downwards and forwards; then the humerus is in the position of
+extension.
+
+During these movements of the humerus, there exists an essential
+factor--that is, the scapular balance. (It is the same as what occurs in
+man when he balances his arm in the antero-posterior plane.) When the
+humerus is flexed, the scapula moves in such a way that the superior
+portion projects forwards; when it is extended, the scapula, on the
+other hand, is inclined more backwards. But it is necessary to add that,
+during these displacements, the scapulo-humeral angle varies; it tends
+to close during the flexion of the humerus, and becomes more open during
+extension.
+
+The movements and the relations of the humerus and the scapula are
+clearly represented in Figs. 41 and 42, reproduced from the
+chromophotographic studies of Professor Marey--studies relative to the
+analyses of the movements of the horse.[13] They show clearly the
+movements of flexion and extension of the humerus, also the balancing of
+the scapula which accompanies the movements.
+
+  [13] E. J. Marey, 'Analyses of the Movements of the Horse by the
+       Chromophotograph' (_La Nature_, June 11, 1898).
+
+[Illustration: FIG. 41.--FLEXION OF THE HUMERUS: RIGHT ANTERIOR LIMB OF
+THE HORSE, EXTERNAL SURFACE (AFTER A CHROMOPHOTOGRAPHIC STUDY BY
+PROFESSOR MAREY).]
+
+[Illustration: FIG. 42.--EXTENSION OF THE HUMERUS: RIGHT ANTERIOR LIMB
+OF THE HORSE, EXTERNAL SURFACE (AFTER A CHROMOPHOTOGRAPHIC STUDY BY
+PROFESSOR MAREY).]
+
+=The Articulation of the Elbow, or the Humero-ulnar Articulation.=--In
+this articulation, which is constructed in the form of a true hinge, the
+movements of flexion and extension alone are possible. In flexion, the
+forearm, directed forwards, is folded on the arm, with which, in certain
+circumstances, it comes in contact. For example, in a horse of mettle
+which leaps over an elevated obstacle, the animal forcibly raises his
+fore-limbs by flexing them. Flexion is produced to the same extent, and
+even more so, and for a longer period, in felides which crouch.
+
+In extension, on the contrary, the forearm is carried backward. This
+movement being limited only by the contact of the tip of the olecranon
+with the bottom of the olecranon fossa of the humerus, the forearm is
+enabled, in this case, to move until it is in line with the arm. For
+example, during walking, when one of the anterior limbs, having reached
+the end of its resting stage, is considerably inclined downwards and
+backwards.
+
+The apex of the olecranon process--that is to say, the point of the
+elbow--forms a marked prominence, more salient in flexion than in
+extension, as in the corresponding region of the human elbow.
+
+=The Radio-ulnar Articulation.=--It is in the dog and the cat, in which
+the two bones of the forearm articulate by their extremities only, and
+remain separate in the rest of their extent, that the articulations call
+for special notice.
+
+In the upper part, the radius rotates on itself; while below, it rotates
+around the ulna. It follows that the forearm, which in all quadrupeds is
+in a state of permanent pronation, can, in carnivora, take the position
+of supination, or rather, of demi-supination. In fact, whatever be the
+mobility of the two bones of the forearm, the movement is not able to
+bring the palmar surface to the front, but only to direct it towards the
+median line.
+
+=The Articulation of the Wrist.=--Here are found, as in man, three
+superimposed articulations: the radio-carpal, intercarpal, and
+carpo-metacarpal.
+
+If we remember the movements which take place at the plane of these
+articulations in man, and take account of the fact that the mobility of
+the limbs is reduced just in proportion as they are simplified in
+structure so as to become organs of support only, we can easily
+comprehend that, in the horse and the ox, and, in a word, animals that
+have a canon bone, the movements of the wrist are little varied in
+character, while in carnivoræ, on the other hand, they are relatively
+more so.
+
+We will remember that in the ox and the horse the region of the wrist is
+called the _knee_.
+
+In flexion, the hand is bent backwards; in extension it is carried
+forwards. These two movements take place especially in the radiocarpal
+and intercarpal articulations. In the first of these articulations, it
+is the superior row of the carpus which glides backwards and forwards on
+the corresponding articular surface of the forearm. In the second
+articulation, it is the second row which moves; gliding on the inferior
+articular surfaces of the row above it. This inferior row carries the
+metacarpus with it; for the carpo-metacarpal articulation is much less
+mobile than either of the other two.
+
+In flexion, the articular surfaces are separated from one another in
+front; and the changes of form which result from this are noticeable on
+the anterior surface of the 'knee.' Moreover, at that moment this region
+contrasts markedly in its outlines with the parts above it and below
+it--that is to say, with the corresponding surfaces of the forearm and
+of the canon bone.
+
+As for the lateral movements, by which the hand is inclined outwards and
+inwards in its movements at the wrist, they exist to an appreciable
+extent in the cat and the dog only; in order to understand this, it is
+enough to compare the shape of the articular surfaces of this region in
+carnivora and the horse, for example. In the latter, those surfaces are
+almost plane; in the cat, on the contrary, they are curved (inferior
+surface of the forearm, concave; superior border of the carpus, convex).
+These latter, then, are, in form, similar to those which exist at the
+same level in the human being; this explains the possibility of
+analogous movements of the whole hand--that is to say, of the movements
+of abduction and adduction.
+
+=The Metacarpo-phalangeal Articulations.=--With regard to the mobility,
+it is in these articulations, as in those of the wrist--that is to say,
+although in all quadrupeds the first phalanges can be flexed and
+extended on the metacarpus, it is only in the cat and dog that lateral
+movement is possible. Indeed, in the horse, in which the principal
+metacarpal terminates inferiorly in two convex surfaces, which are
+separated by a crest; and where the whole articulates with a cavity on
+the superior extremity of the first phalanx; because of the hinging of
+these surfaces, there can only be movements of opening and closing of
+this articulation. The first phalanx is directed backwards during
+flexion and forwards during extension. In the dog and the cat the digits
+can be separated from each other, and also drawn together--that is to
+say, abducted and adducted; but, as in man, these movements can be made
+only when the first phalanges are in the state of extension. During
+flexion they are impossible, because of the tension of the lateral
+ligaments, which increases as the flexion is more pronounced. This can
+be demonstrated, for example, in the cat, which, in order to separate
+the digits, opens the hand widely--that is to say, forcibly raises the
+first phalanges.
+
+=The Interphalangeal Articulations.=--The phalanges are in contact with
+one another by surfaces, which, on one side, are of trochlear form, and,
+on the other, are moulded on these trochleæ; accordingly, at the level
+of these articulations, the movements of flexion and extension only can
+take place.
+
+In the felidæ, the claws which the third phalanges bear cannot be
+utilized when the latter are in a state of extension, at which time,
+being forcibly raised, they are, in fact, placed on the outer sides of
+the phalanges, which are grooved to receive them. But when the animal
+wishes to use them, it flexes those third phalanges, of which the
+terminal extremity is then projected forward, and the claws are ready to
+fulfil their function. But at the same time it extends the first
+phalanges, to produce a certain tension of the flexors of the digits,
+and thus enable the latter to act with greater efficacy, with a minimum
+of contraction. We can demonstrate this action experimentally on
+ourselves. It is enough to carry the first phalanges forcibly into a
+state of extension; the third phalanges then become flexed, quite
+spontaneously, by the tension of the tendons of the flexors which are
+inserted into them.
+
+At the same time, if we examine the felidæ which we have taken as
+examples, when the first phalanges are in the state of extension, the
+digits will be found to be separable, as we have already indicated in
+connection with the metacarpo-phalangeal articulations, with the result
+that the claws are then able to lacerate a wider surface.
+
+The extension of the ungual phalanx, which determines the retraction of
+the claw and stops its action, is the mechanical result of an elastic,
+fibrous apparatus which is attached to each of the third phalanges, and
+has its origin of the second.
+
+
+THE POSTERIOR LIMBS[14]
+
+  [14] Examine Figs. 21, 33, 34, 38, 39, 49.
+
+The posterior limbs are divided, as are the inferior limbs of the human
+being, of which they are the homologues, into four parts: pelvis, thigh,
+leg, and foot.
+
+
+The Pelvis
+
+The pelvis, which incompletely limits the abdominal cavity, inferiorly
+in the vertical position of the body and posteriorly in the normal
+attitude of quadrupeds, is formed by the iliac bones and sacrum--the
+coccyx forming a prolongation of the latter. We have already described
+the two latter (pp. 10 and 11) in connection with the vertebral column,
+of which they form the inferior or posterior portion or segment,
+according to the attitude of the individual.
+
+=The Iliac Bone.=--The iliac or coxal bone, is a paired or
+non-symmetrical bone, united below to its fellow of the opposite side,
+while it is separated from it above by the sacrum.
+
+In all animals, as well as in man, the iliac bone, at the beginning of
+life, consists of three parts, which afterwards unite and fuse together
+and join at the middle of the bottom of a deep cavity which is situated
+on the outer aspect of the bone--the cotyloid cavity.
+
+Of those three portions when examined in the human iliac bone, that
+above the cavity is the ilium; that on the inside is the pubis; and the
+last, the lower one, is the ischium. In quadrupeds, the iliac bone
+being, in its entirety, directed much more obliquely downwards and
+backwards, the relative position of these constituent parts is a little
+modified: the ilium is in front, the pubis is still internal, but in a
+more inferior position, and the ischium is behind the cotyloid cavity.
+We notice this peculiarity of the development of the iliac bone because
+it is customary to continue to apply to the osseous regions which
+correspond to these parts the names by which they were known when
+independent bones.
+
+[Illustration: FIG. 43.--THE LEFT ILIAC BONE OF THE HUMAN BEING:
+EXTERNAL SURFACE, PLACED IN THE POSITION WHICH IT WOULD OCCUPY IN THE
+SKELETON OF A QUADRUPED.
+
+1, Cotyloid cavity; 2, ilium; 3, iliac crest; 4, anterior iliac crest;
+5, posterior iliac spine; 6, pubis; 7, tuberosity of the ischium; 8,
+obturator foramen; 9, ischiadic spine.]
+
+[Illustration: FIG. 44.--LEFT ILIAC BONE OF A QUADRUPED (HORSE):
+EXTERNAL SURFACE.
+
+1, Cotyloid cavity; 2, ilium, external iliac fossa (directed upward in
+the horse); 3, iliac crest; 4, anterior iliac spine (directed inwards in
+the horse, it is the angle of the haunch); 5, posterior iliac spine
+(directed inwards in the horse; it is the angle of the haunch); 6,
+pubis; 7, tuberosity of the ischium; 8, obturator foramen; 9, ischiadic
+spine, or subcotyloid foramen.]
+
+The bones which form the skeleton of the pelvis of quadrupeds are
+proportionally more elongated and less massive than those of the human
+pelvis (Figs. 43 and 44).
+
+We find, on the external surface of the iliac bone, the cotyloid cavity,
+whose border is interrupted by the cotyloid notch; a deep notch which
+looks downwards.
+
+In front of this cavity is the ilium. This portion, narrow in the part
+which is next the cavity, is directed forwards and upwards, expanding
+more and more as it passes upwards. It presents an external or superior
+surface (external in some animals, superior in others), which recalls
+the external iliac fossa; and an internal or inferior surface, at the
+superior part of which is found the auricular surface for articulation
+with the sacrum.
+
+The anterior border of the ilium is rough; this is the iliac crest, at
+the extremities of which we find, below or outside, a prominence which
+corresponds to the anterior superior iliac spine of man; and internally
+another projection which corresponds to the posterior iliac spine.
+
+Immediately above the cotyloid cavity is a rough crest, which is known
+as the _supracotyloid crest_, which is, however, no other than the
+homologue of the sciatic spine. In front of this prominence, the border
+of the ilium, which is notched, forms the great sciatic notch.
+
+If, still taking the cotyloid cavity as the point of departure, we
+proceed inwards--that is, towards the median line of the body--we find
+the pubis; if in a posterior direction, the ischium. These two portions,
+pubis and ischium, limit an oval orifice, the subpubic foramen.
+
+In the human skeleton, the pubis of one side is united to that of the
+opposite side, to form the pubic symphysis. In the animals which we are
+now studying a portion of the ischium enters into the formation of the
+symphysis; in other words, it is formed, not only by the body of the
+pubis, but also by the descending branch or ramus of the pubis and a
+portion of the ascending branch or ramus of the ischium, which are fused
+with those of the opposite side. It results that, though in the human
+being the symphysis is short and the ischio-pubic arch large, in
+quadrupeds it is the opposite. In them the arch is a mere slot, and
+being formed by the ischium alone, merits the name of the ischial arch.
+The ischio-pubic symphysis is very large, and forms a horizontal surface
+relatively extensive, a sort of floor, on which rest certain organs
+which occupy the cavity of the pelvis.
+
+The posterior and external angle of the ischium is rough and prominent;
+it is the tuberosity of the ischium. This forms a projection under the
+skin; it also does in man when the trunk is strongly inclined forwards,
+while the thighs are maintained in the vertical position. In
+marsupials--opossum, kangaroo, and phalanger--the pelvis at its pubic
+region is surmounted by two bones, situated one on each side of the
+median line, and arranged in the form of a fork of two prongs (Fig. 45).
+These, which are called _marsupial bones_, support the pouch which, in
+animals of this genus, lodges their young, which, at the time of birth,
+are incapable of supporting a separate existence, their development
+being absolutely incomplete.
+
+[Illustration: FIG. 45.--PUBIC REGION OF THE PELVIS OF A MARSUPIAL
+(PHALANGER, FOX).
+
+1, Symphysis pubis; 2, obturator foramen; 3, marsupial bones.]
+
+In the cetaceans--for example, the dolphin--because of the absence of
+posterior limbs, the pelvis is represented by two separate bones only,
+which have no connection with the vertebral column. In birds, the pelvis
+is remarkable for its elongated form (see for its form Fig. 21, and for
+details Fig. 46). The cotyloid cavity is pierced by an opening, and
+presents on its posterior border, which is here a little prominent, a
+surface with which the great trochanter is in contact.
+
+The ilium is very highly developed, and is fused in the median line with
+the ilium of the opposite side, the last dorsal vertebræ, the lumbar
+vertebræ, and the sacrum. Because of these relations with the dorsal
+vertebræ, it is in contact anteriorly with the last ribs, which
+consequently emerge from each side of the iliac region of the pelvis.
+
+The ischium forms a plate of bone which, in part, closes the external
+portion of the cavity of the pelvis. Its superior border is separate for
+a certain distance from the external border of the ilium; there is thus
+left an opening of more or less considerable size, which represents or
+takes the place of the great sciatic notch.
+
+[Illustration: FIG. 46.--PELVIS OF A BIRD (THE COCK): EXTERNAL SURFACE,
+LEFT SIDE.
+
+1, Ilium; 2, ischium; 3, pubis; 4, inferior extremity of the pubis; 5,
+sciatic foramen; 6, oval foramen, homologous to the obturator; 7,
+coccygeal vertebræ.]
+
+The pubis, long and slender, is in connection with the inferior border
+of the ischium, of which it follows the general direction; and
+circumscribes with this latter, below the cotyloid cavity, an oval
+orifice, which is the homologue of the obturator foramen. Its inferior
+extremity reaches beyond the corresponding part of the ischium, bending
+towards the middle line, but without joining the pubis of the opposite
+side. On this account there is no symphysis pubis in birds.
+Nevertheless, an exception must be noted in the case of the ostrich, the
+pubic bones of which meet in the middle line, and are articulated in
+form of a symphysis.
+
+
+The Thigh
+
+A single bone, the femur, forms the skeleton of this portion of the
+lower limb.
+
+=The Femur.=--The bone of the thigh is, in man, directed downwards and
+inwards; this obliquity, we may remind the reader, is due to the
+difference in length of the two condyles which form its inferior
+extremity; the internal is the more prominent, the result of which is
+that when the femur is held vertically, the internal condyle descends
+lower than the external. Now, as those two articular expansions rest on
+the horizontal plane formed by the upper extremity of the tibia, it
+follows that the superior part of the femur inclines towards the side of
+the shorter condyle--that is to say, outwards--and that, the leg being
+vertical, it and the bone of the thigh unite in forming an angle, of
+which the apex is directed towards the inner side of the knee.
+
+In many mammals the two condyles are equally prominent, the result of
+which is that the femur inclines neither inwards nor outwards, but is
+contained in a plane parallel to the axis of the trunk; while the leg is
+included in the same plane. Nevertheless, although contained in the
+plane which we have just indicated, the femur is obliquely placed, and
+directed downwards and forwards; it accordingly forms, with the pelvis,
+an angle, of which the opening is directed to the anterior aspect of the
+body.
+
+In reptiles and in birds the femur and leg are both placed in the same
+plane, but this plane is not parallel to the axis of the trunk. This is
+the result, on the one hand, of the thorax being wide, and, on the other
+hand, of the femur, which is directed forwards, being in contact by its
+anterior extremity with the lateral aspect of the costal region, it is
+thus necessarily placed in a direction forwards and outwards, and the
+knee is further removed from the axis of the trunk than is the
+articulation which unites the thigh with the pelvis.
+
+The femur, like the humerus, is almost completely enveloped by muscular
+masses, which bind it to the lateral walls of the abdomen. Its inferior
+extremity alone is free, and is always the more so in proportion to its
+elongation--that is to say, as it belongs to an animal whose foot is
+more divided. The femur in this respect conforms to the law which we
+have indicated in connection with the bone of the arm, in which the
+development, as to length, is in proportion to the division of the hand.
+
+If we compare the femur of certain animals with that of man, we see that
+the corresponding details of form are readily recognisable, but they are
+slightly modified. Thus, on examining the superior extremity, we find
+there a head, a neck, a great trochanter, and a lesser; but the neck is
+usually short and thick, and the great trochanter does not occupy the
+same level with regard to the articular head of the bone. In man, the
+great trochanter does not rise to the level of the head of the femur; in
+the dog and the cat it approaches that level; in the horse and in
+ruminants it rises above it.
+
+With regard to the inferior extremity, its surfaces undergo
+modifications which are further accentuated as we pass from the
+digitigrades to the ungulates, or unguligrades. We know that in man the
+femoral trochlea is continuous behind, without interruption, with the
+condyles--that is to say, that each of the condyles is the continuation
+of one of the lips of the trochlea. We have just said that the trochlea
+is continuous without interruption with the condyles; this is accurate.
+Nevertheless, we must remark that, at the level of the junction of these
+surfaces, the bone presents a slight constriction, which is more marked
+on the external than on the internal aspect. This constriction, which is
+but slightly marked in man, is accentuated in the dog and the cat; in
+the ruminants and the solipeds it is still more pronounced so that we
+may say that in these latter the trochlea and the condyles are almost
+completely separated.
+
+There is another modification in regard to the prominence and extent of
+the two lips of the trochlea. In man, the external lip of the trochlea
+reaches higher than the internal, and it is more prominent in front. In
+the dog, these lips are equal with regard to thickness, but the external
+still reaches higher than the internal; in the cat, they are equal in
+every respect; in ruminants and solipeds the internal lip is wider,
+thicker, and rises higher than the external.
+
+In animals the trochlea is, as a general rule, narrower than in man, and
+the condyles are more prominent posteriorly; so that, when viewed from
+one of the lateral aspects, the inferior extremity of the femur is, in
+them, better developed in the antero-posterior direction.
+
+In birds, the femur is shorter than the bones of the leg; its great
+trochanter is in contact with a prominence which occupies the posterior
+part of the border of the cotyloid cavity. Instead of articulating at
+the level of the knee, with the knee-cap and tibia only, as in man, it
+articulates, in addition, with the superior extremity of the fibula. A
+similar arrangement is found in marsupials and reptiles.
+
+=The Knee-cap.=--This bone, developed in the thickness of the tendon of
+the triceps muscle of the thigh, is in contact, by its posterior
+surface, with the femoral trochlea. The two articular surfaces which are
+applied to the lips of the trochlea present, with regard to their
+extent, an inequality which is in proportion to the arrangement which we
+have above indicated--that is, while in man it is the external surface
+which is the larger, in the horse it is the internal. We shall see what
+the general form of the knee-cap is when we come, later on, to study
+more particularly the posterior limbs of some animals.
+
+
+The Leg
+
+The skeleton of the leg consists of two bones: the tibia and the fibula.
+The tibia is the more internal and the larger of the two; the fibula is
+slender, and situated on the outer side, and a little posterior to, the
+preceding. The fibula is more or less developed according to the
+species; in some it is complete, in others it is very much atrophied.
+
+This peculiarity may be compared with that which we have drawn attention
+to regarding the development of the ulna; but here the seriation is less
+distinct. Not only in the different species, but even in the individuals
+of the same species, the development of the fibula presents little
+regularity. In quadrupeds, the bones of the leg are directed obliquely
+downwards and backwards, so that they form, with the femur, which is
+directed obliquely downwards and forwards, an angle, the apex of which
+is placed at the anterior surface of the knee.
+
+=Tibia.=--The tibia of quadrupeds is readily comparable with that of
+man; as in the case of the latter, its shaft has three surfaces--an
+external, which is hollowed out in its upper portion, and becomes
+anterior below; an internal, slightly convex and subcutaneous; the
+posterior, which presents, in its superior part, a crest, the oblique
+line of the tibia, and some rugosities. The borders separate the
+surfaces. The anterior border, or crest of the tibia, is prominent in
+its superior part; below it gradually disappears in passing towards the
+internal aspect of the inferior extremity. The external and internal
+borders separate the corresponding surfaces from the posterior one.
+
+The superior extremity is thick, and expands in forming three
+tuberosities: two lateral and an anterior. The anterior tuberosity,
+situated at the superior part of the crest of the tibia, is very
+prominent; for this reason the superior extremity is very much expanded
+in the antero-posterior direction--hence it results that this diameter
+is equal to the transverse, and sometimes even greater. In man, it is
+the latter which is the larger. The anterior tuberosity is visible under
+the skin.
+
+The inferior extremity, less thick, is prolonged internally by a
+prominence which corresponds to the internal malleolus of man. In
+animals whose fibula is but slightly developed the tibia presents, on
+the external part of its inferior extremity, a small prominence, which
+replaces the fibular malleolus. The ruminants must, however, be
+excepted, in which we find in this region a special bone, which certain
+authors look on as the inferior part of the fibula (see p. 97). The
+inferior surface of this extremity of the tibia is articular; and is in
+contact with one of the tarsal bones, the astragalus. Because the
+superior surface of this latter has the form of a pulley, a pulley much
+more marked than that on the human astragalus, the corresponding surface
+of the tibia, which has the opposite form, presents two lateral
+cavities, separated by a median ridge, which is directed forwards and
+slightly outwards; this ridge projects into the groove of the pulley.
+
+=The Fibula.=--This bone, situated at the back of the external
+surface of the tibia, is, as we have said, more or less developed. Its
+superior extremity, or head, articulates with the external tuberosity
+of the tibia. Its inferior extremity, when it exists--it is this
+which disappears in animals which have the fibula incompletely
+developed--forms a prominence which, placed on the external surface of
+the inferior extremity of the tibia, articulates with the astragalus,
+and recalls the external malleolus of man.
+
+We have stated above that it is the inferior extremity of the fibula
+which disappears when the bone is incompletely developed; it is
+necessary to except the bat, in which the fibula, fairly well developed
+at its inferior extremity, by which it articulates with the tibia, thins
+off in its superior portion, and does not reach the corresponding
+extremity of the latter. Further, as in this animal the surface of the
+knee, which corresponds to the anterior surface of the same region in
+other animals, is turned backwards, the result is that the fibula is
+situated on the inner side of the tibia, instead of being placed on the
+outer.
+
+
+The Foot
+
+The foot, in animals, as well as in man, is formed of three portions,
+which, as we pass from the part which articulates with the leg towards
+the terminal extremity, are: the tarsus, the metatarsus, and the toes.
+These three portions are the homologues of the carpus, the metacarpus,
+and the fingers, which, as we have already seen in the case of the hand,
+are the osseous groups which form its skeleton. The tarsus is formed of
+short bones, as the carpus is; these are, in man, seven in number. The
+bones are arranged in two rows: one, the posterior, formed of two bones
+superimposed--the astragalus, by which the tarsus articulates with the
+leg, and the calcaneum, which forms the prominence of the heel; and an
+anterior row formed of five juxtaposed ones--the cuboid, situated
+externally, and the scaphoid internally, in front of which are found the
+three cuneiforms. To the tarsus succeeds the metatarsus, whose form
+reminds us very much of that of the metacarpals.
+
+With regard to the toes, which we enumerate in proceeding from the most
+internal to the most external, they are formed of phalanges, which are
+three in number for the four outer toes; but the number is reduced to
+two in the case of the first--that is, the so-called great-toe.
+
+The bones of the tarsus are not seven in all animals; they are fewer in
+ruminants and solipeds. We already know that, in the latter, the
+metacarpals and the digits are equally reduced in number; the same is
+the case for the metatarsals and the toes. We will analyze these
+differences when dealing with the species individually.
+
+When we studied the anterior limbs, we saw in passing from the
+plantigrades to the digitigrades, and finally the ungulates, or
+unguligrades, as the hand became hyperextended, the carpus was raised
+and more and more removed from the ground. We shall establish the
+existence of the same condition in the posterior limbs; in the
+plantigrades the tarsus rests on the ground; in the digitigrades it is
+removed from it; while in the unguligrades the distance which separates
+it from the point of support is still more considerable; and it is,
+indeed, necessary to imagine that if these latter were plantigrades,
+would occupy the position on the ground which is indicated by Fig. 47.
+
+In veterinary anatomy the tarsus is called the _ham_; a name we adopt
+in conformity with usage, but which we cannot but regret, as in human
+anatomy the ham is the region of the posterior surface of the knee.
+
+The general arrangement of the region of the digits of the posterior
+limbs in birds, presents some points of interest.
+
+We shall merely say with regard to the metatarsus, that it is formed by
+a single bone, which in the cock is furnished towards its inferior third
+with a pointed process, the _spur_. At the inferior part, there is,
+however, found another, which is but very slightly developed, and with
+which the first phalanx of the innermost toe articulates.
+
+The toes are, in the majority of species, four in number:[15] an
+internal, which is directed backwards, and corresponds to the great-toe;
+the others are directed forwards. This arrangement is constant in
+grallatores (wading birds), gallinaceæ[16] (domestic fowls), and
+raptores (birds of prey).
+
+  [15] In spite of the fact that the custom is to designate the terminal
+       portions of the foot of birds by the name of digits, we prefer to
+       employ here the terms _foot_ and _toes_. In adopting this
+       decision we believe we are acting according to a more didactic
+       method. Homology of names should, in our opinion, always
+       accompany homology of regions.
+
+  [16] With regard to the gallinaceæ, we must add that in certain
+       varieties the number of toes is five; those which are directed
+       forwards are three in number; the internal one which passes
+       backward, is double. The two toes which are the subject of this
+       special arrangement are placed very close together, and are
+       nearly always superimposed. This condition is found in the Houdan
+       and Dorking breeds.
+
+[Illustration: FIG. 47.--POSTERIOR LIMB OF THE HORSE PLACED IN THE
+POSITION WHICH IT SHOULD OCCUPY IF THE ANIMAL WERE A PLANTIGRADE: LEFT
+LIMB, EXTERNAL SURFACE.
+
+1, Tibia; 2, astragalus; 3, calcaneum; 4, metatarsus; 5, first phalanx;
+6, second phalanx; 7, third phalanx.]
+
+In climbing birds (parrots, woodpeckers, and toucans), the innermost
+toe is not only directed backward, but the external toe accompanies it
+in that direction; consequently, there are two posterior and two
+anterior toes. Sometimes they are all directed forwards; this
+disposition is found in the martins. In some birds, the number of toes
+is reduced to three: the cassowary shows this reduction; in others, the
+number is still further diminished--the ostrich, for example, has but
+two.
+
+[Illustration: FIG. 48.--SKELETON OF THE FOOT OF A BIRD (THE COCK): LEFT
+SIDE, EXTERNAL SURFACE.
+
+1, Metatarsus; 2, spur; 3, rudimentary metatarsal; 4, first toe; 5,
+second toe; 6, third toe; 7, fourth toe.]
+
+Further, we find that, in general, the number of the phalanges
+increases, when we examine the toes in commencing with the most internal
+(Fig. 48): this has two; then the following one three; that which comes
+next in order has four; and the most external toe has five. The
+phalanges of this last are short; so that, although it is formed by a
+larger number of bones, it is not the longest of the toes.
+
+
+THE POSTERIOR LIMBS IN SOME ANIMALS.
+
+=Plantigrades=: =Bear= (Fig. 33, p. 50).--The external iliac fossa is
+very deep. The femur is longer than the bones of the leg; the great
+trochanter does not reach the level of the head of the femur. The
+fibula is well developed; it is united to the tibia at its superior and
+inferior extremities only.
+
+The foot, which, as in the case of the hand, rests on the ground by the
+whole extent of its plantar surface, presents five toes; the shortest of
+these is the internal--that is, the toe which corresponds to the
+great-toe in man; the third and fourth are the longest, and they are
+almost equal; there is a very slight difference in favour of the fourth,
+which is slightly superior in dimensions to the third.
+
+=Digitigrades=: =Cat=, =Dog= (Fig. 34, p. 52).--The external iliac
+fossa, which looks outwards, is deep; the iliac crest is convex
+anteriorly, the convexity is continued from one iliac spine to the
+other.
+
+[Illustration: FIG. 49.--PELVIS OF THE DOG, SEEN FROM ABOVE.
+
+1, Iliac crest; 2, external iliac fossa; 3, sacrum; AA´, bi-iliac
+diameter; BB´, bi-ischial diameter.]
+
+In the dog, the distance which separates the anterior iliac spines is
+less than that which separates the ischia (Fig. 49). On a skeleton which
+we measured, the transverse diameter, the distance from the anterior
+iliac spine of one side to that of the opposite side, was 8 centimetres,
+whilst the distance which separated the ischia was 105 millimetres; on
+another skeleton, the first measurement was 127 metres, and the second
+was 146 millimetres. It seems to us unnecessary to multiply examples.
+
+In the cat, the iliac spines are but slightly marked; the result is
+that the iliac crest is almost confounded with the inferior and superior
+borders of the ilium. The two diameters referred to above are almost
+equal (Fig. 50).
+
+We draw particular attention to what we have just noted in regard to the
+transverse proportions of the iliac and ischiatic regions of the dog and
+the cat. These relations are evidently of importance with regard to
+shape, since the iliac crests and the ischia are noticeable beneath the
+skin.
+
+[Illustration: FIG. 50.--PELVIS OF A FELIDE (LION), VIEWED FROM ABOVE.
+
+1, Iliac crest; 2, external iliac fossa; 3, sacrum; AA´, bi-iliac
+diameter; BB´, bi-ischial diameter.]
+
+In the dog, the shaft of the femur is slightly convex in front; but in
+the cat it is straight. The borders of the shaft are slightly marked, so
+that it is almost cylindrical. The _linea aspera_, less prominent than
+in man, gains in width what it loses in elevation; it constitutes what
+may almost be called a rough _surface_. This surface is narrower in its
+middle portion than at its extremities, where it bifurcates to go
+upwards to the two trochanters, and downwards to the two condyles. At
+the superior extremity, the neck is short, the great trochanter reaching
+almost to the level of the head of the femur; the digital _cavity_,
+which is situated on the internal surface of the great trochanter, is
+very deep. At its inferior extremity it projects strongly backward. The
+trochlea is narrow; in the cat its two lips are equally prominent, while
+in the dog the external is a little more elevated than the internal,
+which on its part is a little thicker. The trochlea is still more
+independent of the condyles than in the human femur; it is separated
+from these latter by a slight constriction.
+
+The knee-cap is long and narrow.
+
+The tibia of the dog is slightly curved from before backward: it has the
+form of an elongated S; this conformation is in great part due to the
+very marked projection of the anterior tuberosity and of the superior
+portion of the crest, which, a little below that tuberosity, turns
+abruptly backwards, and thus describes a curve the concavity of which is
+directed forward. The superior part of the external surface is very much
+hollowed out.
+
+The superior extremity is much thicker than the inferior one. It is not
+only wide in the transverse direction, but is more especially extended
+from before backwards; the prominence of the anterior tuberosity is the
+cause of the elongation of this antero-posterior diameter. On the
+posterior part of the external tuberosity is found a surface to which
+the superior extremity of the fibula is applied.
+
+The inferior extremity presents an articular surface, which is formed of
+two lateral cavities, separated by a crest, which is directed obliquely
+forwards and outwards. The internal part is prominent, and forms the
+internal malleolus.
+
+With regard to the fibula, it is united to the tibia by its extremities
+and by the inferior half of its shaft. This latter is more expanded
+below than in its upper part. The superior extremity is flattened from
+without inwards. The inferior extremity projects beyond the articular
+surface of the tibia, and forms the external malleolus, which, instead
+of, as in man, descending further than the tibial malleolus, stops at
+the same level, and even descends a little less than does the latter.
+
+In the cat, the curve of the tibia is less pronounced; this is due to
+the fact that the crest, instead of being concave in its middle portion,
+is slightly convex anteriorly. The fibula, less flattened than that of
+the dog, is united to the tibia by its extremities only, and is separate
+in the rest of its extent.
+
+The bones of the tarsus are seven in number, and arranged as in man,
+with this difference (which is easily comprehended), that their general
+relations are changed on account of the vertical direction of the
+tarsus. For example, the astragalus, instead of being above the
+calcaneum, is situated in front of it; the cuneiform bones, instead of
+being situated in front of the scaphoid, are found below it, etc.
+
+These animals have but four well-developed metatarsals; that which
+corresponds to the great-toe is represented merely by a small
+style-shaped bone, situate at the internal part of the region.
+
+Nevertheless, we find this toe fully developed in some dogs.
+Notwithstanding this, the bones which form it are, however, but
+rudimentary, and much smaller than those of the innermost digit of the
+fore-limb.
+
+Sometimes it is double; this condition is demonstrable in individuals
+belonging to breeds of large size. The median metatarsals are more fully
+developed than the other bones of the same region which are next them.
+Viewed as a whole, the metatarsal bones are a little longer than the
+metacarpals; the result is that the distance which separates the tarsus
+from the ground is a little greater than that which separates the carpus
+from the plane on which the anterior limbs rest. The length of the
+calcaneum still further exaggerates this difference, and, as in the
+animals with which we shall occupy ourselves later on, the projection
+which this bone forms is distinctly higher than that which is produced
+by the pisiform.
+
+The metatarsus, as a whole, is a little narrower than the metacarpus;
+not only on account of the presence of a thumb in the anterior limb,
+but, further, because the bones of this latter region are wider than
+those of the corresponding part of the posterior limb.
+
+The phalanges closely resemble those of the anterior limbs.
+
+=Unguligrades=: =Pig= (Fig. 38, p. 58).--The pelvis in this animal
+presents a few of the characters which we shall again meet with in the
+ruminants and the solipeds; however, the posterior (or internal) iliac
+spines are relatively more widely separated from one another than in the
+latter. This arrangement reminds us of that found in the carnivora.
+
+The femur presents nothing very special. The knee-cap is thick, and
+ovoid in outline.
+
+The fibula is completely developed, as in the carnivora; and is
+connected with the tibia at both its extremities.
+
+The tarsus consists of seven bones. The astragalus and the calcaneum
+differ slightly from those of ruminants.
+
+The foot, like the hand, has two median digits which rest on the ground
+by their third phalanges; and an internal and an external digit, which
+are removed from it. The metatarsals are a little longer than the
+metacarpals.
+
+[Illustration: FIG. 51.--PELVIS OF THE OX: SUPERIOR SURFACE.
+
+1, Iliac crest; 2, external iliac fossa; 3, sacrum; AA´, bi-iliac
+diameter; BB´, bi-ischiadic diameter.]
+
+=Unguligrades=: =Sheep=, =Ox= (Fig. 39, p. 61).--The pelvis of ruminants
+of this group closely resembles that of the horse, which we will study
+later on (see p. 99). That which we must at once point out is that, with
+regard to the ratio formed by a comparison of the bi-iliac and
+bi-ischiatic diameters, it may be placed between the ratio obtained in
+comparing those diameters in the pelvis of the carnivora and that of the
+solipeds. Indeed, in the ruminants, the distance which separates the
+ischia exceeds the width of one iliac only, and does not equal, as in
+the felide, the total width of the anterior part of the pelvis (Fig.
+51). In the skeleton of the ox, which forms part of the anatomical
+museum of the École des Beaux-Arts, the bi-ischiadic diameter is 39
+centimetres, whilst the width of one iliac crest is 29 centimetres, so
+that, in contrast to that which we find in the dog, the width of the
+ischiadic region is less than that formed in front by the addition of
+the iliac crests.
+
+The great trochanter is large, and extends beyond the level of the plane
+in which the head of the femur is found.
+
+In the ox, the linea aspera, instead of being a narrow crest, is spread
+out, and forms in reality a surface; the posterior surface of the femur.
+At the inferior and external part of this surface is situated a cavity
+which surmounts the corresponding condyle, and is known as the
+_supracondyloid fossa_. On the internal part of the same region there
+are a series of tubercles, which, because of their position in relation
+to the corresponding condyle, constitute the _supracondyloid crest_.
+
+The internal lip of the trochlea is much thicker and much more prominent
+than the external.
+
+The details which we have just now examined in connection with the ox
+are less marked in the sheep.
+
+The trochlea, narrow as a whole, is clearly separate from the condyles
+by a very marked constriction.
+
+The patella, which is thickened in the antero-posterior direction, has
+the shape of a triangular pyramid with the base upwards. Its posterior
+surface, which articulates with the trochlea, presents an arrangement
+which is adapted to the disposition of this latter--that is to say, the
+surface which is in contact with the internal lip is larger than that
+which articulates with the lip of the opposite side.
+
+The tibia of the ox is proportionately shorter than that of the sheep.
+The shaft of this bone is flattened from before backwards, in its
+inferior half. The median crest of the articular surface of the inferior
+extremity is the most prominent part of that region.
+
+[Illustration: FIG. 52.--TARSUS OF THE OX: POSTERIOR LEFT LIMB,
+ANTERO-EXTERNAL SURFACE.
+
+1, Tibia; 2, coronoid bone of the tarsus; 3, superior articular surface
+of the astragalus; 4, inferior articular surface of the astragalus; 5,
+calcaneum; 6, cuboido-scaphoid bone; 7, great cuneiform bone--the small
+cuneiform bone is situated at the back of the latter; 8, principal
+metatarsal--the small, or rudimentary, metatarsal bone is very small; it
+is situated at the back of the preceding, and is not to be seen in the
+sketch. It would be visible if the view were directly lateral, but then
+the superior and inferior articular surfaces of the astragalus would be
+less apparent.]
+
+The fibula is extremely atrophied. The shaft and superior extremity of
+this bone are represented merely by a simple ligamentous cord, which is
+sometimes ossified. There remains of the fibula, as a portion well and
+distinctly developed, the inferior extremity only. This presents itself
+under the form of a small bone situated in the region ordinarily
+occupied by the inferior extremity of the outer bone of the leg--that is
+to say, the external part of the inferior extremity of the tibia; this
+little bone articulates with the astragalus and the calcaneum. Some
+authors consider it to be a tarsal bone, and describe it under the name
+of the coronoid bone of the tarsus (Fig. 52, 2). It is not, perhaps,
+quite legitimate to describe it as a bone of this region, for it has
+not a homologue in the tarsus of other animals. Its external surface is
+rough; its superior border is furnished with a small pointed process
+occupying a depression which is provided for it by the tibia. It reaches
+lower down than the latter, and forms in this way a sort of external
+malleolus, which frames, on the outer aspect, the mortise in which the
+astragalus is maintained.
+
+The tarsus, as a whole, has an elongated form; it is formed of five
+bones: the astragalus, calcaneum, cuboid and scaphoid, which coalesce,
+to form a single bone, and two cuneiform bones, which correspond to the
+second and third cuneiform bones of the human foot. These cuneiforms are
+called, from their size, commencing internally, by the names small and
+great cuneiform.
+
+The calcaneum is long and narrow; it is longer than that of the horse;
+it is on the anterior and external part that the bone (coronoid tarsal
+bone) which represents the inferior extremity of the fibula is situated.
+It forms the prominence known as _the point of the ham_, a prominence
+which is no other than the heel, which, in the unguligrades, is, as we
+have already said, very far removed from the ground.
+
+The astragalus, which is elongated in the vertical direction, has three
+articular surfaces disposed in the form of trochleæ: a superior
+trochlea, which is in contact with the skeleton of the leg, and which is
+present in all animals; an inferior, which replaces the articular head
+found on the anterior aspect of the astragalus in man; this articulates
+with the portion of the scaphoido-cuboid that corresponds to the
+scaphoid; and, lastly, a posterior trochlea with which the calcaneum
+articulates. Of these three trochleæ, the superior is the most strongly
+marked. Between this latter and the inferior is found, on the anterior
+surface of the astragalus, a deep depression, which, during flexion of
+the foot on the leg, receives a prominence which the inferior extremity
+of the tibia presents in its median portion.
+
+We can easily recognise the trochleæ which we have been discussing, in
+the little bones which children use 'to play at bones'; these bones are
+no other than the astragali of sheep.
+
+We have already mentioned that the scaphoid and the cuboid are
+ankylosed; they form by their union an irregular bone, on which the
+astragalus and calcaneum are supported.
+
+The cuneiforms articulate with the internal half of the superior
+extremity of the principal metatarsal; the external half of this
+metatarsal articulates with the portion of bone which represents the
+cuboid.
+
+The metatarsus is represented by a principal metatarsal, formed by the
+coalescence of two metatarsals; we also find in this region a very small
+rudimentary metatarsal.
+
+The metatarsus is a little longer than the metacarpus; its transverse
+measurement is a little less; on the other hand, it is a little thicker
+in antero-posterior direction; from these two differences it results
+that the body of the metatarsus is quadrilateral, whereas the metacarpus
+presents only an anterior and a posterior surface.
+
+The rudimentary metatarsal is a very small roundish bone, situated at
+the back of the superior extremity of the principal metatarsal.
+
+The phalanges closely resemble those of the anterior limbs;
+nevertheless, the first and second phalanges differ from the latter in
+the fact that they are a little longer and narrower.
+
+At the back of the metatarso-phalangeal articulations, as in the
+corresponding region of the anterior limbs, are found the sesamoid
+bones. Such also exist at the articulations of the second and third
+phalanges.
+
+=Unguligrades=: =Horse= (Fig. 40, p. 64).--The pelvis of the horse
+presents a general form which sharply differentiates it from that of the
+carnivora; in fact, the ilium is twisted in such a way that the external
+iliac fossa does not look outwards, but upwards. It results from this
+twist that the anterior iliac spine, which we have seen to be directed
+downwards in the carnivora, has become external; and this prominence is
+much farther removed from the vertebral column than in the dog or cat.
+On the other hand, the posterior iliac spine, which is directed upwards
+in the carnivora, has become internal; it is also placed nearer to the
+vertebral column, with the result that the distance which separates this
+spine from that of the bone of the opposite side is proportionately
+less.
+
+The internal iliac spine, which is conical in shape, and curved upwards,
+forms a prominence known as _the angle of the crupper_; the external
+iliac spine, thick and provided with tuberosities, forms a
+clearly-defined prominence; this is the angle of the _haunch_.
+
+The iliac crest, extending directly from one spine to the other, is
+curved, its concavity being turned upwards. The external iliac fossa,
+which looks upward, is limited anteriorly by this crest, and is, like
+the latter, slightly hollowed. The portion of the bone which connects
+the ilium to the region occupied by the cotyloid cavity is extremely
+narrow; posteriorly, the bone enlarges again to form the ischial and
+pubic portions.
+
+The tuberosity of the ischium, thick and curved upwards, but less so
+than in the ox, forms the most prominent part of the posterior border of
+the region of the thigh; this projecting portion, so sharply defined in
+spare subjects, is known as the _point_ or _angle of the buttock_.
+Contrary to what we have indicated in the case of the dog, the distance
+which separates the ischiatic tuberosities is inconsiderable in
+proportion to that which we find between the external iliac spine of one
+side and that of the opposite. The bi-ischiatic diameter does not even
+equal the width of one iliac bone measured at the level of its crest
+(Fig. 53). On the skeleton of the horse in the École des Beaux-Arts, the
+distance which separates the tuberosities of the ischia is 225
+millimetres; that between the two spines of each iliac bone is 25
+centimetres.
+
+The anterior region of the crupper is thus much broader than that
+occupied by the ischia.
+
+The femur is relatively short. Its shaft is rectilinear, and does not
+present the anterior convexity which is found on the human femur, and
+which we indicated when discussing that of the dog. The shaft of the
+bone, instead of being prismatic and triangular, presents four surfaces;
+the anterior, internal, and external, almost pass into each other, being
+separated one from the other merely by rounded and slightly marked
+borders; the posterior surface, which is plane, replaces the linea
+aspera, which in the horse, instead of presenting the appearance of a
+crest, is considerably widened. The numerous irregularities which this
+surface presents give insertion to the muscles which correspond to those
+attached to the linea aspera.
+
+Between this posterior surface and the external is found a rough
+prominence which curves forward; this was designated by Cuvier the
+_third trochanter_; it replaces the external branch of the superior line
+of bifurcation of the linea aspera; other authors call it the
+_infratrochanteric crest_, because it is situated below the great
+trochanter. At the inferior part of the same region is found a deep
+fossa, the borders of which are rough; this is the _supracondyloid
+fossa_.
+
+[Illustration: FIG 53.--PELVIS OF THE HORSE: SUPERIOR SURFACE.
+
+1, Iliac crest; 2, external iliac fossa; 3, sacrum; AA´, bi-iliac
+diameter; BB´, bi-ischiatic diameter.]
+
+Between the posterior surface and the internal are found: above, the
+lesser trochanter, which is long and rough; below, at the level of the
+supracondyloid fossa, an equally rough surface known by the name of the
+_supracondyloid crest_.
+
+The superior extremity is flattened from before backwards. The neck is
+not well marked. The great trochanter is very prominent, and projects
+beyond the level of the head of the femur. We divide the great
+trochanter into three parts: the summit, which is the most elevated
+portion; the convexity, which is situated in front; and the crest,
+formed by muscular impressions, situated outside and below the
+convexity. The digital fossa is situated behind and below the summit of
+the great trochanter. With regard to the lesser trochanter, it is placed
+so far down that it really forms part of the shaft of the bone, with
+which, besides, we have described it.
+
+On the inferior extremity of the femur are two condyles and a trochlea;
+the condyles are clearly separated from this latter by a marked
+constriction.
+
+The trochlea is directed with a slight obliquity downwards and inwards;
+its internal lip is much thicker and more prominent than the external;
+this is, accordingly, a condition exactly the opposite of that which
+characterizes the corresponding region of the human femur.
+
+The knee-cap is lozenge-shaped; its superior angle projects upward, and
+produces a prominence at the part which corresponds to the base of the
+human patella, the part which is here the thickest portion of the bone.
+Its anterior surface is convex and rough. Its posterior surface presents
+two lateral articular facets, separated by a crest; this surface is in
+contact with the trochlea of the femur, and, as it is the internal lip
+of the latter which is the more developed, it results therefrom that the
+internal articular surface of the knee-cap is larger than the external.
+
+The knee-cap contributes to the formation of the region of the posterior
+limb which is called the _stifle_.
+
+The tibia is large in its upper portion; in its inferior part it is
+flattened from before backwards. The posterior surface of the shaft
+presents an oblique line, below which are found vertical rough lines for
+the insertion of muscles. The external surface is hollowed out in its
+upper part. The anterior tuberosity of the tibia rises just to the level
+of the flat articular surface; it is hollowed in its median portion by a
+vertical groove of elongated form, which receives the ligament that
+binds the knee-cap to the tibia. The external tuberosity is more
+prominent than the internal; in it is found a groove for the passage of
+the anterior tibial muscle.
+
+The inferior extremity, flattened from before backwards, presents a
+surface which is moulded on the trochlea of the astragalus; the median
+crest of this surface is thick, and descends lower posteriorly than the
+tuberosities which are situated on the external and internal aspects of
+this extremity.
+
+Of the two tuberosities, that which is internal is comparable to the
+internal malleolus of man, the one on the outer side forms a sort of
+external malleolus; but this latter here belongs to the tibia, and not
+to the fibula.
+
+The fibula, in fact, does not reach the inferior extremity of the tibia;
+it is a poorly developed bone, elongated and terminating inferiorly in a
+point, at the middle of the shaft of the tibia or at its lower third.
+Its superior extremity, which is slightly expanded, articulates with the
+tuberosity which occupies the outer aspect of the corresponding
+extremity of the tibia.
+
+The bones of the tarsus are six in number: the calcaneum and astragalus
+form the upper row; the cuboid, scaphoid, and two cuneiforms form the
+lower (Fig. 54).
+
+The astragalus has not, as in ruminants, an inferior trochlea for
+articulation with the scaphoid; this portion of the bone presents a
+surface which is slightly convex. It articulates with the tibia by a
+trochlea that occupies not only the superior surface, but also the
+anterior. This trochlea, which is directed slightly obliquely downwards
+and outwards, has a very pronounced form; its lips, which are extremely
+prominent, determine by their anterior part one of the features which we
+recognise on the anterior aspect of the _ham_--a feature which is still
+more accentuated when the metatarsus (_canon_) is extended on the leg.
+On the internal surface of the astragalus is found a tubercle, which
+forms a projection in the corresponding region of the ham.
+
+The calcaneum, which is not quite so long as that of the ox, forms by
+its summit a prominence which is called _the point of the ham_.
+
+The cuboid is small; the scaphoid is large, and flattened from above
+downwards. Of the two cuneiforms, the more external is the larger; it
+closely resembles the scaphoid; it is flattened from above downwards as
+is the latter; but it is a little smaller in size. The small cuneiform,
+which occupies the inner side of the tarsus, is the smallest bone in
+this region; it is sometimes divided into two parts; this raises the
+number of the cuneiforms to three, and that of the bones of the tarsus
+to seven.
+
+[Illustration: FIG. 54.--TARSUS OF THE HORSE: LEFT POSTERIOR LIMB,
+ANTERIOR SURFACE.
+
+1, Tibia; 2, internal tuberosity of the inferior extremity of the tibia
+(homologue of the internal malleolus of man); 3, external tuberosity of
+the inferior extremity of the tibia (homologue of the external
+malleolus); 4, median crest lodged in the groove of the pulley of the
+astragalus; 5, pulley of the astragalus; 6, internal tuberosity of the
+astragalus; 7, calcaneum; 8, cuboid; 9, scaphoid; 10, great cuneiform,
+the small cuneiform is placed behind this latter; 11, principal
+metatarsal; 12, external rudimentary metatarsal. The internal
+rudimentary metatarsal, being more slender than the external, does not
+appear in the figure.]
+
+The bones of the metatarsus and the phalanges are equal in number to the
+corresponding bones in the anterior limbs; they are formed on a type
+analogous to that of these latter. Accordingly, we shall merely indicate
+the differences which characterize them.
+
+The principal metatarsal is longer than the metacarpal of the same
+class; its shaft is more cylindrical; its inferior extremity is somewhat
+thicker. The external rudimentary metatarsal is better developed than
+the internal; in the metacarpus the reverse is the case.
+
+The phalanges so far resemble those of the anterior limb that, as
+differential characters, we need point out only the following: the first
+phalanx of the hind-foot is a little shorter than that of the fore-foot;
+its inferior extremity is a little narrower, and its superior extremity
+a little thicker. The second phalanx is a little less expanded
+laterally.
+
+The difference in appearance which the three phalanges, anterior and
+posterior, respectively present are to be borne in mind; for they are
+correlated to the general form of the fore and hind feet. We will
+establish this point when we come to study the hoof (see Figs. 101 and
+102, p. 257). In the fore-foot the ungual phalanx has its inferior
+surface limited externally by a circular border, while the same bone of
+the hind-foot has this surface a little narrower, more concave, and
+limited by two curved borders which unite anteriorly to form an
+angle--an arrangement which gives to the general outline of this region
+the form of the letter V.
+
+
+Articulations of the Posterior Limbs
+
+=The Coxo-femoral Articulation.=--The head of the femur is received in
+the cotyloid cavity; these are the osseous surfaces in contact in this
+articulation. They are maintained in position by a fibrous capsule and a
+round ligament. To this latter is found attached, in the horse, a
+fasciculus which, commencing, as does the round ligament, at the
+depression on the head of the femur, emerges from the cotyloid cavity by
+the notch which is present in its circumference, and is attached to the
+anterior border of the pubes, to blend with the tendon of the rectus
+muscle of the abdomen. This is the pubio-femoral ligament.
+
+The movements which this joint permits are the same in the quadrupeds as
+in man, but less extensive. They are: flexion and extension, abduction
+and adduction, the two latter being much more limited than the former.
+There is also rotation.
+
+By flexion, the inferior extremity of the femur is directed forwards;
+the bone of the thigh then takes a more oblique direction than the
+normal. This movement takes place, for example, when the animal carries
+forward one of its hinder limbs. Extension, which takes place in an
+inverse sense, is produced when the foot is fixed on the ground, while
+the body is projected forward. It is also produced in the action of
+kicking.
+
+As for the lateral movements--viz., abduction and adduction--they are
+less extensive than the preceding movements. The absence of the
+pubio-femoral ligament in other quadrupeds than the horse explains why
+in them abduction is less limited than in the latter. Indeed, it is the
+tension of this ligament, occasioned by the abduction of the thighs,
+which arrests more quickly the movement in question.
+
+=Articulation of the Knee.=--This articulation, as in man, is formed by
+the femur, the patella, and the tibia.
+
+In the horse the ligament of the patella is not single, but consists of
+three parts, designated, on account of their position, by the respective
+names of external, internal, and median patellar ligaments. The two
+former come from the angles on the corresponding borders of the
+knee-cap; the median springs from the anterior surface and inferior
+angle of the same bone. They all three pass to their termination on the
+anterior tubercle of the tibia. The external ligament is the strongest,
+and the internal ligament the least developed.
+
+In the dog, the cat, the pig, and the sheep, the patellar ligament
+consists of a single band. The articulation is further strengthened on
+the sides by lateral ligaments--an internal and an external.
+
+With regard to the principal movements, these are flexion and extension,
+to which may be added movements of rotation of limited extent. In
+flexion, the leg bends on the thigh; its inferior extremity is directed
+upwards and backwards; the angle which the tibia naturally forms with
+the femur becomes less obtuse.
+
+But it should be understood that one part of this description--that
+which has relation to the leg--holds good only when the femur is in its
+normal condition, or in flexion. Indeed, at the close of the movement in
+which, during a step, the foot is in contact with the ground--that is,
+at the termination of the resting stage--the inferior extremity of the
+tibia is directed backwards. But the femur is then in a state of
+extension, and in regard to this latter the attitude of the leg is
+unchanged.
+
+[Illustration: FIG. 55.--EXTENSION OF THE LEG: RIGHT POSTERIOR LIMB OF
+THE HORSE, EXTERNAL SURFACE. (AFTER A CHRONOGRAPHIC STUDY BY PROFESSOR
+MAREY.)]
+
+At this moment, notwithstanding the direction, which recalls that which
+it has at the time of flexion, the leg is not bent on the thigh; on the
+contrary, it is almost in the line of its continuation (Fig. 55). As we
+have done in connection with the articulations of the anterior limbs, we
+borrow this figure from the interesting chronophotographic studies of
+Professor Marey.[17]
+
+  [17] E. J. Marey, 'Analysis of the Movements of the Horse by the
+       Chronophotograph' (_La Nature_, June 11, 1898).
+
+=The Tibio-tarsal Articulation and of the Bones of the Tarsus.=--In the
+region which veterinary anatomists call the ham, the articulations of
+the leg and foot alone call for special study in the case of the horse.
+The articulations of the bones of the tarsus, and of these with the
+metatarsus, do not offer any interest with regard to mobility, this
+being almost wholly absent at that level.
+
+The leg and the astragalus, in a general way, are placed in contact by
+such articular surfaces that the resulting joint, which is a true hinge,
+permits movements of flexion and extension only. Indeed, as we have
+indicated above, the tibia is furnished, on the inferior surface, with a
+crest that fits into the deep groove which is situated on the
+corresponding surface of the astragalus.
+
+During flexion, the anterior surface of the foot tends to approach the
+anterior surface of the leg, the angle formed by these two segments
+becoming more and more narrowed. The displacement in the opposite
+direction characterizes extension.
+
+In other quadrupeds, the articulations which bind together the bones of
+the tarsus possess a little more freedom of movement. The shape of these
+bones, and particularly the shape of the surfaces of the astragalus,
+which are in contact with them, allow movements in this region, in the
+case of the dog and cat, which, without being so extensive as those of
+the human foot, in the subastragaloid articulation, nevertheless, recall
+the mobility which we find in the human species at this level--that is
+to say, rotation, abduction, and adduction of the foot.
+
+As for the articulations of the metatarsus with the phalanges, and of
+the phalanges with one another, they resemble those of the anterior limb
+too closely that it should be necessary to study them here. Such a study
+would be, in this case, but a repetition (see p. 76, a description of
+the articulations in question).
+
+
+THE HEAD IN GENERAL, AND IN SOME ANIMALS IN PARTICULAR
+
+When we compare, by the examination of one of their lateral aspects, the
+skull of man and the same region in other mammals, it is easy to observe
+that the relative development of the cranium and face is entirely
+different. In the case of man the cranium is large, and the face
+relatively small; in animals the face is proportionally much more highly
+developed. The measure of the facial angle permits us to note these
+differences, and the figures relative to the value of this angle are
+sufficiently demonstrative to induce us to indicate those which are, in
+a general way, connected with some of the forms in individuals which
+here occupy our attention. In the first place, we must remember that the
+angle in question is more acute, as the cranium is less developed in
+proportion to the facial region (Figs. 56 and 57). It is especially to
+this character that we wish to draw attention.
+
+  Man      70°-80°
+  Cat      41°
+  Dog      28°-41°
+  Sheep    20°-25°
+  Ox       18°-20°
+  Ass      12°-16°
+  Horse    11°-13°
+
+Besides, in animals the cranium is very prominent superiorly, and the
+face, more or less elongated, is sharply projected downwards and
+forwards; in man the cranial region occupies not only the superior, but
+also the posterior part; the face is short and of a compact form. The
+human head, in its general aspect, may be compared to a sphere, while
+the skull of the quadrupeds presents the aspect of a quadrangular
+pyramid, with the base turned upwards and the summit at the incisor
+teeth.
+
+=Direction of the Head.=--Before entering on the study of the bones of
+the head, it is necessary, in our opinion, to agree as to the position
+in which we shall suppose it to be placed.
+
+The question may seem to be one of little importance; nevertheless, it
+cannot be regarded as indifferent, since authors are not all agreed on
+this subject.
+
+Some suppose it to be placed vertically--that is, with the incisor teeth
+turned directly downwards. Others, on the contrary, suppose it to be
+placed horizontally, resting on the whole length of the lower jaw, the
+face being then turned upwards. These two extreme methods of arrangement
+appear to us to possess inconveniences--at least, for comparison with
+the human head.
+
+[Illustration: FIG. 56.--HUMAN SKULL: MEASURE OF THE FACIAL ANGLE BY THE
+METHOD OF CAMPER. ANGLE BAC = 80°.
+
+The internal wall of the cranial cavity is marked by the dotted line.]
+
+[Illustration: FIG. 57.--SKULL OF THE HORSE: MEASURE OF THE FACIAL ANGLE
+BY THE METHOD OF CAMPER.[18] ANGLE BAC = 13°.
+
+The internal wall of the cranial cavity is shown by the dotted line.]
+
+  [18] We have indicated on this sketch of the skull of the horse the
+       facial angle measured by the method of Camper, in order that the
+       correspondence with Fig. 56 may be more complete. But it is
+       certain that the procedure here employed is in practice not
+       satisfactory, since the apex of the angle, as we can demonstrate,
+       is found to be situated within the contour of the head, and that,
+       consequently, it is rather difficult to localize it precisely in
+       the case of a given skeleton. Further, because of the absence of
+       the base of the nose in the complete skull, the auriculo-nasal
+       line cannot be accurately fixed. It would be the same for most
+       other animals. This is why the method employed for these latter
+       is preferably that of Cuvier, or, again, that of Cloquet. In the
+       former, the apex of the angle of Camper is transferred to the
+       free border of the upper incisors, but these teeth may be absent,
+       and, on the other hand, ruminants are destitute of them. In the
+       second, the same apex is placed at the alveolar border, and the
+       angle then becomes fairly easy to appreciate.
+
+Indeed, if, when the head is vertical, the same regions of the face
+(forehead, nose) are, in the case of animals as well as man, turned
+forward, the lower jaw ceases to merit its appellation, as it is then
+situated, not below, but behind the upper. Furthermore, if this
+position is chosen, for example, for modelling or drawing, it cannot be
+obtained without difficulty when we have to deal with an isolated piece
+of the skeleton, on account of the absence of equilibrium, which it is
+necessary to obviate. It is true that the question of convenience should
+not take precedence of all others, and it suffices for us in this
+connection to recall, in regard to the human pelvis, that, although the
+older anatomists used to represent it as resting commodiously on the
+three angles which terminate it at its lower part (ischial tuberosities
+and coccyx), this attitude being false, it is customary now to incline
+the superior aspect forwards, inasmuch as this arrangement more nearly
+conforms to reality, in spite of the fact that it is a little more
+difficult so to dispose an isolated pelvis. Further, to return to the
+head; if its vertical direction can be demonstrated, for example, in
+many horses, it is not sufficiently general to be adopted as the classic
+position.
+
+In regard to the facility of placing in position, the horizontal
+direction is certainly to be preferred; but this is also far removed
+from the natural position in the animal while in the state of repose. On
+the other hand, the mind is not satisfied with the idea that certain
+regions of the face, such as the nose and the forehead, are then
+directed upwards. And yet it is necessary to come to a decision, seeing
+that what we are now investigating applies also to the position to which
+it is necessary to give the preference in placing the skeleton of the
+head when we wish to draw it in profile. That which we adopt is a
+compromise, but to us it seems more rational.
+
+The position of the head of the horse, to be normal, should be such as
+to give it an inclination of 45°. In this case the lower jaw is still
+posterior; and, for this reason, we see in adopting this position some
+inconveniences from a didactic point of view. Accordingly, we will
+suppose the head brought a little nearer to the horizontal, and this,
+from the imaginative point of view, has certainly an advantage which we
+cannot afford to neglect when addressing artists.
+
+Indeed, let us suppose that to a clay model of a human head we wish to
+give the aspect of the head of a quadruped. We should elevate the
+occiput; and then, taking hold of the lower part of the face, we should
+lengthen it, not in a direction precisely antero-posterior, but
+downwards and forwards. It is obviously this latter procedure which, on
+the other hand, is carried out when a person wishes to give to his own
+face some resemblance to the muzzle of a quadruped.
+
+It is true that, in the position we have adopted, the face is directed
+obliquely downwards and forwards, and that there may result a certain
+confusion in describing the position of its different parts. On
+this account, with the object of not making complications, we
+purpose, for the present, to substitute, for example, for the term
+'antero-superior'--which when speaking of the position of the forehead
+and nose would be more exact--the term 'anterior,' which is sufficiently
+comprehensible. The mouth will be, for the same reason, referred to as
+being situated at the inferior part of the face, and not the
+antero-inferior.
+
+=The Skull.=--The elevation of the cranial region becomes especially
+appreciable when we examine the occipital bone. Before verifying this
+fact, it is not superfluous to recall the general arrangement which this
+bone presents in the human skull. A portion of the occipital bone
+occupies the base of the skull; but this base in man is horizontal; to
+this region succeeds the shell-shaped portion of the occipital bone,
+which, passing vertically upwards, forms with the preceding portion an
+angle situated at the level of the external occipital protuberance, and
+of the curved line which starts from it on each side. In animals a
+portion of the occipital bone is horizontal, it is true; but this bone
+being sharply bent at the level of the occipital foramen and condyles,
+the result is that the portion which surmounts these latter looks
+backwards, and is limited above by the external occipital protuberance,
+which forms the culminating point of the skull; this point is situated
+between the ears.
+
+[Illustration: FIG. 58.--SKULL OF ONE OF THE FELIDÆ (JAGUAR): LEFT
+LATERAL ASPECT.
+
+1, Posterior surface of the occipital bone; 2, external occipital
+protuberance; 3, condyle of the occipital bone; 4, jugular process; 5,
+parietal bone; 6, frontal bone; 7, orbital process; 8, orbital cavity;
+9, squamous portion of the temporal bone; 10, external auditory canal,
+in front of which is situated the zygomatic process; 11, tympanic bulla;
+12, superior maxillary bone; 13, intermaxillary or incisor bone; 14,
+nasal bone; 15, anterior orifice of the nasal cavity; 16, malar bone;
+17, ungual or lachrymal bone; 18, inferior maxillary bone; 19, condyle
+of the inferior maxillary bone; 20, coronoid process; 21, incisor teeth;
+22, canine teeth; 23, molar teeth.]
+
+[Illustration: FIG. 59.--SKULL OF THE LION: LEFT LATERAL ASPECT.
+
+This figure is intended to show that in the lion the contour of the face
+between the nasal bones and the cranial region is more flattened than in
+other felidæ, such as the tiger, jaguar, panther, and domestic cat. This
+difference is shown by comparison of this figure with the preceding one
+(Fig. 58). We are indebted to M. Tramond, the well-known naturalist, for
+the indication of this differential character which, from the artistic
+plastic point of view, is one of real interest.]
+
+This protuberance, prolonged on each side by the superior curved line of
+the occipital bone, is so much the more prominent as this bone bends
+sharply a second time, so as to form a third portion, which, looking
+forwards, forms part of the anterior aspect of the skull, and proceeds
+to articulate with the parietals. On this third portion is found a crest
+which, proceeding from the occipital protuberance, is continuous in
+front with the parietal crests, to which we will again refer in speaking
+of the parietal bones.
+
+On the inferior surface of the human occipital bone are found, at the
+level of, and external to, the condyles two bony elevations which bear
+the name of _jugular eminences_. They are long in quadrupeds, and
+constitute what are designated by some authors the _styloid processes_,
+but they must not be confounded with the processes of the same name
+which in the case of man form part of the temporal bone. These processes
+are very highly developed in the pig, horse, ox, and sheep.
+
+In the ox, the occipital bone is deprived of the protuberance, and is
+not bent on itself in the anterior portion, neither does it form the
+most salient part of the skull; this latter, which is situated at the
+level of the horns, belongs to the frontal bone. In the pig, also, the
+occipital bone is not bent upon itself in its anterior portion, but
+forms the summit of the head. The occipital protuberance, hollowed on
+its posterior surface, rises vertically, and rests upon the parietal
+bone, with which it forms an acute angle.
+
+The parietals, two separate bones in the dog and the cat, but fused in
+the median line in the ox, sheep, and horse, are of special interest in
+regard to the two crests which, in the carnivora, and also in the pig
+and the horse, occupy their external surface, and, after diverging from
+one another, are continued by a crest which crosses the frontal bone
+and ends at the external orbital process of the latter bone.
+
+These crests, known as the _parietal_ or _temporal crests_, recall both
+in position and relations the temporal curved line of the parietal bone
+of man. They contribute, as in the case of the latter, to the formation
+of the boundaries of the temporal fossa.
+
+[Illustration: FIG. 60.--SKULL OF THE DOG: LEFT LATERAL ASPECT.
+
+1, Posterior surface of the occipital bone; 2, external occipital
+protuberance; 3, occipital condyle; 4, jugular process; 5, parietal
+bone; 6, frontal bone; 7, orbital process; 8, orbital cavity; 9,
+external auditory canal, in front of which is found the zygomatic
+process; 10, tympanic bulla; 11, superior maxillary bone; 12,
+intermaxillary or incisor bone; 13, nasal bone; 14, anterior opening of
+the cavity of the nasal fossæ; 15, malar bone; 16, lachrymal bone; 17,
+inferior maxillary bone; 18, condyle of the inferior maxillary bone; 19,
+coronoid process; 20, incisor teeth; 21, canine teeth; 22, molar teeth.]
+
+In the carnivora, these crests are situated, throughout their whole
+length, in the median line, the temporal fossæ being, accordingly, as
+extended as they possibly can be. In certain species, the development of
+these crests is such that they form by their union a vertical plate,
+which, in separating the two temporal fossæ, gives them a greater depth.
+In the pig, the parietal crests, analogous in this respect to the
+temporal curved lines of the parietal bones of man, are separated by an
+interval, proportionately less extended, however, than that of the human
+skull. The parietal bone in the ox and the sheep does not enter into the
+formation of the anterior surface of the skull; it is formed by an
+osseous plate, narrow and elongated transversely, which, with the
+occipital bone, constitutes the base of the region of _the nape of the
+neck_. It is bent upon itself at the level of its lateral portions so as
+to occupy the temporal fossa.
+
+The anterior surface of the frontal bone, which is depressed in the
+median line in the dog, but plane in the horse, is limited by two
+crests, which, situated on the prolongation of the parietal crests,
+diverge more and more from one another in proportion as they occupy a
+lower position. This surface terminates externally in two processes,
+which are the homologues of the external orbital processes of the human
+frontal bone.
+
+The superior border of these orbital processes, situated on the
+prolongation of the corresponding parietal crests, contributes to limit
+the temporal fossa. Each of these orbital processes terminates in the
+following manner: In the bear, dog, cat, and pig, in which the orbital
+cavities are incompletely bounded by bone, this process, slightly
+developed, is not in connection, by its inferior extremity, with any
+other part of the skeleton of the region. In the ox and the sheep, it
+articulates with a process of the malar bone. In the horse, it
+articulates with the zygomatic process of the temporal bone. The
+inferior margin of this process forms a part of the boundary of the
+anterior opening of the orbital cavity.
+
+The supra-orbital foramen, which does not exist in carnivora, occupies
+in the horse the base of the orbital process. In the ox, it is situated
+a little nearer the middle line; and its anterior orifice opens into an
+osseous gutter which is directed upwards towards the base of the horn,
+while inferiorly it meets the inferior border of the frontal bone; in
+the sheep this groove is but slightly developed. In this latter, as in
+the ox, it is the frontal bone which forms the most elevated portion of
+the skull. In fact, being bent upon itself at a certain level, its
+external surface is formed of two planes: one, posterior, which is
+inclined downwards and directed backwards; the other, anterior, is also
+inclined downwards, but with a forward obliquity. At the union of these
+planes the bone forms an elbow, on either side of which are found the
+osseous processes on which the horns are mounted.
+
+[Illustration: FIG. 61.--SKULL OF THE PIG: LEFT LATERAL ASPECT.
+
+1, Occipital bone; 2, condyle of the occipital; 3, jugular process; 4,
+parietal bone; 5, parietal crests; 6, frontal bone; 7, orbital process;
+8, orbital cavity; 9, external auditory canal; 10, zygomatic process;
+11, superior maxillary bone; 12, intermaxillary or incisor bone; 13,
+nasal bone; 14, anterior orifice of the cavity of the nasal fossæ; 15,
+malar bone; 16, lachrymal bone; 17, inferior maxillary bone; 18, condyle
+of the inferior maxillary bone; 19, incisor teeth; 20, canine teeth; 21,
+molar teeth.]
+
+In the bear, the anterior margin of the frontal bone is prolonged by two
+small tongues of bone, which, descending on the lateral borders of the
+nasal bones, articulate with the superior half of the latter.
+
+The temporal bone is, as in man, furnished with a squamous portion,
+from which springs the zygomatic process, which is directed towards the
+face, to terminate in the following manner: in the carnivora, the pig,
+and ruminants, it articulates with the malar bone by its inferior
+border; in the horse, it insinuates itself as a sort of wedge between
+the malar bone and the orbital process of the frontal bone, with which
+it articulates, as we have already pointed out, and contributes, by a
+portion situated in front of this articulation, to form the boundary of
+the anterior opening of the corresponding orbital cavity. As in man, the
+zygomatic process arises by two roots: one, transverse, behind which is
+situated the glenoid cavity of the temporal bone; the other,
+antero-posterior, which proceeds to join above with the superior curved
+line of the occipital bone.
+
+Behind the glenoid cavity is found the external auditory canal, and,
+further back still, the mastoid process. This latter, but slightly
+developed in the carnivora, a little more so in the ruminants, and still
+more in the horse, has its external surface traversed by a crest, _the
+mastoid crest_, which, after becoming blended with the antero-posterior
+root of the zygomatic process, proceeds with this latter to join the
+superior occipital curved line.
+
+Below the auditory canal is situated a round prominence, highly
+developed in carnivora; this is _the tympanic bulla_, also called _the
+mastoid protuberance_; it is an appendage of the tympanum.
+
+
+The Face
+
+The bone of this region, around which all the others come to be grouped,
+is, as in man, the superior maxillary. The relations of this maxillary
+with the neighbouring bones is not exactly the same in all animals; for
+example, in the ox, sheep, and horse, in which the bones of the nose are
+wide in their upper part, and in which the lachrymal bone, which is very
+highly developed, encroaches on the face, the superior maxillary does
+not meet the frontal bone; it is separated from it by the above-named
+bones. It unites with it, on the other hand, in the dog and the cat. In
+the bear, it is separated from the bones of the nose by a small tongue
+of bone which springs from the anterior border of the frontal--a
+process which we have noticed in connection with this latter.
+
+[Illustration: FIG. 62.--THE SKULL OF THE OX: LEFT LATERAL ASPECT.
+
+1, Occipital condyle; 2, jugular process; 3, parietal bone; 4, frontal
+bone; 5, osseous process, which serves to support the horn (horn-core);
+6, orbital cavity; 7, external auditory canal, in front of which is
+found the zygomatic process; 8, temporal fossa; 9, superior maxillary
+bone; 10, intermaxillary or incisor bone; 11, nasal bone; 12, anterior
+orifice of the cavity of the nasal fossæ; 13, malar bone; 14, lachrymal
+bone; 15, inferior maxillary bone; 16, condyle of the inferior maxillary
+bone; 17, incisor teeth; 18, molar teeth.]
+
+In the pig, ox, sheep, and horse, the external surface is traversed, to
+a greater or less extent, by a crest which is situated on the
+prolongation of the inferior border of the malar bone. This crest, which
+is straight in the horse, but curved with its convexity upwards in the
+ox and the sheep, is known as _the maxillary spine_ or _the malar
+tuberosity_: it gives attachment to the masseter muscle, and, in the
+horse, is distinctly visible under the skin. It does not exist in the
+carnivora. On the same surface is situated the sub-orbital foramen.
+
+The inferior border is hollowed out into alveoli, in which are implanted
+the superior molar and canine teeth. This border is prolonged forwards
+from the alveolus, which corresponds to the first molar tooth, to
+terminate, after a course more or less prolonged, at the alveolus of the
+canine. This space, more or less considerably expanded, which thus
+separates these teeth is called the _interdental space_; but this
+denomination is not applicable to ruminants, because these latter
+possess neither canine nor incisor teeth in the upper jaw (see p. 125,
+dentition of the ox and sheep). The superior maxillary bone of one side
+and that of the opposite side do not meet in the median line in the
+region which corresponds to the incisor teeth; they are separated by a
+bone which, in the human species, is present only at the commencement of
+life, and afterwards coalesces with the maxilla; this is the
+intermaxillary or incisor bone. This bone, which is paired, is formed of
+a central part, which bears the superior incisor teeth; it is prolonged
+upwards and backwards by two processes: one, external, which insinuates
+itself between the superior maxillary and the nasal bone, except in the
+sheep, in which it remains widely separated from the latter; the other,
+internal, which is united to that which belongs to the bone of the
+opposite side to form part of the floor of the cavity of the nasal
+fossæ; the external border of this process, which is separated from the
+body of the bone by a notch, forms the internal boundary of the
+corresponding _incisor opening_ or the _incisor slit_. Owing to the
+absence of superior incisors in ruminants, the intermaxillary bone
+presents no alveoli.
+
+The malar bone, and the os unguis or lachrymal, are more or less
+developed according to the species considered. With regard to the malar
+bone, it is most important to notice the part which it takes in the
+formation of the zygomatic arch, and that its inferior border
+contributes to form the crest to which is attached the masseter muscle.
+
+As for the nasal bones, they present differential characters which, as
+they affect the form of the region which they occupy, are worthy of
+notice.
+
+[Illustration: FIG. 63.--SKULL OF THE HORSE: LEFT LATERAL ASPECT.
+
+1, Posterior surface of the occipital bone; 2, external occipital
+protuberance; 3, occipital condyle; 4, jugular process; 5, parietal
+bone; 6, frontal bone; 7, orbital cavity; 8, zygomatic process of the
+temporal bone; 9, external auditory canal; 10, mastoid process; 11,
+superior maxillary bone or _maxilla_; 12, intermaxillary or incisor
+bone; 13, nasal bone; 14, anterior orifice of the cavity of the nasal
+fossæ; 14´, malar bone; 15, lachrymal bone; 16, inferior maxillary bone
+or _mandible_; 17, inferior maxillary fissure; 18, condyle of the
+inferior maxillary bone; 19, coronoid process of the inferior maxillary
+bone; 20, incisor teeth; 21, canine teeth; 22, molar teeth.]
+
+Their dimensions in length are proportional to those of the face. Very
+small in man, they are more developed in carnivora. We recognise in the
+latter the two curves which characterize them in the human species, and
+which we clearly notice when we view them on one of their lateral
+aspects: a concavity above, and a convexity below. These curves are more
+or less accentuated--very strongly marked in the bulldog, and scarcely
+at all in the greyhound. Moreover, in the carnivora also the nasal bones
+are wider below than above, and form, by their junction, a semicircular
+notch which limits, in its superior portion, the anterior opening of the
+cavity of the nasal fossæ. In the horse they present an opposite
+arrangement with regard to their dimensions in width; broad above, each
+terminates below by forming a pointed process which, separated from the
+intermaxillary bones, is prolonged in front of the nasal orifice.
+
+The inferior maxillary bone is, as in man, formed of a body and two
+branches. But among the many special characteristics of form and size
+which sharply differentiate it from the human bone, one detail must be
+indicated; this is the absence of a mental prominence. Hence it results
+that the anterior border of the body of the lower jaw, instead of being
+directed obliquely downwards and forwards, is, on the contrary, oblique
+downwards and backwards, and that in certain animals this border is
+actually found almost exactly on the prolongation of the inferior border
+of the body of the bone.
+
+On the external surface of the body are found the three mental foramina.
+The superior border is hollowed out by alveoli.
+
+With regard to the branches (_rami_), they terminate in two processes:
+one, the posterior, is the condyle; the other, situated more forwards,
+is the coronoid process, which gives insertion to the temporal muscle.
+These two processes are separated by the sigmoid notch.
+
+For reasons which we will explain further on (see p. 127, movements of
+the lower jaw), the condyle presents differences of form. In the
+carnivora, it is strongly convex from before backwards, expanded
+transversely, and firmly mortised in the glenoid cavity of the temporal
+bone; in the ruminants, it is less convex from before backwards, it is
+more slightly concave in the transverse direction; in the rodents--we
+give as an example the hare (Fig. 64)--the condyle is still convex from
+before backwards, but it is flattened from without inwards.
+
+In the animals in which the muscles of mastication are very highly
+developed, and especially in the carnivora, the osseous regions occupied
+by these muscles are more extensive and more deep than in the human
+species. The length of the coronoid process, the depth of the temporal
+fossa, the extent of the zygomatic arch, the appearance of the external
+surface of each of the rami of the lower jaw, deeply hollowed out for
+accommodation of the masseter, and to provide extensive surfaces of
+insertion for this muscle, are sure proofs furnished by the skeleton of
+the occasionally enormous development of the muscles of mastication.
+
+In the carnivora, a rather strong process, which is directed backwards,
+occupies the angle of the inferior maxilla; it is, accordingly, situated
+below the region of the condyle.
+
+[Illustration: FIG. 64.--SKULL OF THE HARE: LEFT LATERAL ASPECT.
+
+1, External occipital protuberance; 2, occipital condyle; 3, parietal
+bone; 4, frontal bone; 5, orbital process; 6, orbital cavity; 7,
+zygomatic process; 8, external auditory canal; 9, superior maxillary
+bone; 10, intermaxillary or incisor bone; 11, nasal bone; 12, anterior
+opening of the nasal fossa; 13, malar bone; 14, inferior maxillary bone;
+15, condyle of the inferior maxillary bone; 16, incisor teeth; 17, molar
+teeth.]
+
+The teeth which the jaws carry vary in number, and even in appearance,
+according to species; it is useful to note their differences. In order
+to establish the nature of these latter more effectively, we will first
+recall the fact that in man the teeth, thirty-two in number, are equally
+distributed between the jaws, and are divided into incisors, canines,
+and molars, of which the arrangement is thus formulated:
+
+  5_m._  1_c._  2_i._ | 2_i._  1_c._  5_m._
+  --------------------+-------------------- = 32.[19]
+  5_m._  1_c._  2_i._ | 2_i._  1_c._  5_m._
+
+  [19] _I.e._, _i_, incisors; _c_, canines; _m_, molars.
+
+We also note that the incisors are edged, the canines are pointed, and
+that the molars, cubical in shape, have their surface of contact
+provided with tubercles.
+
+The teeth of the cat are thirty in number; they are thus arranged:
+
+  4_m._  1_c._  3_i._ | 3_i._  1_c._  4_m._
+  --------------------+-------------------- = 30.
+  3_m._  1_c._  3_i._ | 3_i._  1_c._  3_m._
+
+Those of the dog number forty-two:
+
+  6_m._  1_c._  3_i._ | 3_i._  1_c._  6_m._
+  --------------------+-------------------- = 42.
+  7_m._  1_c._  3_i._ | 3_i._  1_c._  7_m._
+
+In these animals, the incisors, such as are not damaged by use, are
+furnished, on the free border of their crown, with three tubercles, of
+which one, the median, is more developed than those which are situated
+laterally. We denote these teeth, commencing with those nearest the
+median line, by the names _central incisors_ or _nippers_,
+_intermediate_ and _corner incisors_. The canines, or _fangs_, are long
+and conical; they are curved backwards and outwards. The upper canines,
+which are larger than those of the lower jaw, are separated from the
+most external of the incisors (_corner_) by an interval in which the
+canines of the lower jaw are received. The lower canines, on the other
+hand, are in contact with the neighbouring incisors, and are each
+separated from the first molar which succeeds them by a wider interval
+than that which is situated between the corresponding teeth in the upper
+jaw.
+
+The molars differ essentially from the teeth of the same class in the
+human species. Their crown terminates in a cutting border bristling with
+sharp-pointed projections; this formation indicates that these teeth are
+principally designed for tearing. During the movement of raising the
+lower jaw, which is so energetic in the carnivora, they act, indeed, in
+the same manner as the two blades of a pair of scissors. The largest
+molars are: in the dog, the fourth of the upper jaw, and the fifth in
+the opposite one; in the cat, the third both above and below.
+
+The pig has forty-four teeth disposed in the following manner:
+
+  7_m._  1_c._  3_i._ | 3_i._  1_c._  7_m._
+  --------------------+-------------------- = 44.
+  7_m._  1_c._  3_i._ | 3_i._  1_c._  7_m._
+
+Of the incisors, the nippers and the intermediate ones of the upper jaw
+have their analogues in those of the horse; in the lower jaw, the
+corresponding teeth, straight, and directed forward, rather resemble the
+same incisors in rodents. The corner incisor teeth are much smaller, and
+are separated from the neighbouring teeth. The canine teeth, also called
+_tusks_ or _tushes_, are greatly developed, especially in the male. The
+molars increase in size from the first to the last; they are not
+cutting, as in the carnivora, but they are not flattened and provided
+with tubercles on their surfaces of contact as in the herbivora.
+
+In the ox and the sheep the teeth are thirty-two in number:
+
+  6_m._  0_c._  0_i._ | 0_i._  0_c._  6_m._
+  --------------------+-------------------- = 32.
+  6_m._  0_c._  4_i._ | 4_i._  0_c._  6_m._
+
+As we see from this dental formula, the incisors are found only in the
+lower jaw; they are replaced in the upper jaw by a thick cartilaginous
+pad on which the inferior incisors find a surface of resistance.
+
+These have their crowns flattened from above downwards, and gradually
+become thinner from the root to the anterior border, which is edged and
+slightly convex. These teeth gradually wear away. In proportion to the
+progress of this wear, on account of the fact that it involves the
+anterior borders and upper surfaces of the incisor teeth, and that these
+teeth are narrower towards the root than at the opposite extremity, the
+intervals which separate them tend to become wider and wider; and when
+the roots become exposed by the retraction of the gums, they are then
+separated from one another by a considerable interval. The molars have
+their grinding surface comparable to that of the horse; they increase in
+size from the first to the sixth.
+
+The teeth of the horse are forty in number; they are thus distributed:
+
+  6_m._  1_c._  3_i._ | 3_i._  1_c._  6_m._
+  --------------------+-------------------- = 40.
+  6_m._  1_c._  3_i._ | 3_i._  1_c._  6_m._
+
+As they become worn, these teeth continue to grow, and as, on the one
+hand, this phenomenon takes place throughout the whole life of the
+animal, and, on the other hand, the process of wear brings out and makes
+visible at the surface of friction parts formerly deeper and deeper, and
+of which the configuration varies at different levels, there result
+special features which permit the determination of the age of the animal
+by an examination of its jaws. The incisors are called, commencing with
+those situated nearest the middle line, _central incisors_ or _nippers_,
+_intermediate_ and _corner incisors_. The canines, also designated as
+the _fangs_, exist only in the male. It is exceptional to find them in
+the mare, and when they exist in this latter they are less developed
+than those of the horse. The molars have cuboid crowns; the surface of
+friction is almost square in the case of the upper molars, and is
+inclined so as to look inwards; in the case of the inferior ones, it is
+a little narrowed, and is inclined so as to look outwards. In the upper
+jaw the external surface of the crown is hollowed by two longitudinal
+furrows; in the lower jaw the same surface has only one furrow, which at
+times is but slightly marked.
+
+In the hare the teeth are twenty-eight in number:
+
+  6_m._  0_c._  2_i._ | 2_i._  0_c._  6_m._
+  --------------------+-------------------- = 28.
+  5_m._  0_c._  1_i._ | 1_i._  0_c._  5_m._
+
+The four incisors of the upper jaw are divided into two groups; one of
+these is formed by the two principal teeth, the other by two very small
+incisors which are placed behind the preceding.
+
+Having studied the jaws and examined the arrangement of the teeth, we
+should say a few words on the movements which the lower jaw is able to
+execute. In man, these movements are varied in character: the jaw is
+lowered and raised; it can also be projected forwards and drawn
+backwards, or carried to the right or left side by lateral movements.
+Owing to the different modes of nutrition of animals, with which the
+shape of the teeth is clearly correlated, being more specialized than in
+the human species, the lower jaw is moved in a fashion less varied and
+in the direction most suitable for the mastication of the foods which
+form the aliment of the species considered. Moreover, this is plainly
+shown in the skeleton by the shape of the condyle of the lower jaw (see
+p. 122, different forms of this condyle). In the carnivora, whose teeth,
+as we have seen, are all cutting ones, the jaw rises and falls; the food
+then is, if we consider the two jaws, cut as by the blades of a pair of
+scissors. In the ruminants, the incisors exist only in the lower jaw,
+but the molars are thick and well developed; the food is ground by these
+latter as by millstones, and the movements which favour this action are,
+above all, the lateral. As for the rodents, in which the incisors are
+formed for filing down and cutting through hard resisting bodies, their
+lower jaw moves in the antero-posterior direction, in such a way that
+the inferior incisors alternately advance and recede beneath those of
+the upper jaw. The free cutting border of these teeth effectively
+fulfils the function to which they are destined; their constant wear
+preserves and revivifies the chisel edge which characterizes them,
+without leading to their destruction, for the incisors in rodents are of
+continuous growth.
+
+
+THE SKULL OF BIRDS
+
+=The Skull of Birds= (Fig. 65).--If, because it is less important from
+the artistic point of view, we do not consider it necessary to describe
+in detail the skull of birds, we yet think it useful to indicate, in
+their general lines, the peculiarities it presents.
+
+In this group the skull is generally pear-shaped; to the cranium, of
+which the bones are arranged in such a way as to give it a form more or
+less spherical, succeeds a face more or less elongated, according as the
+bill is more or less developed.
+
+In general, the bones of the skull coalesce very early, with the result
+that it is only in very young individuals that we can determine their
+presence.
+
+We find the skull to consist of an occipital bone, two parietals, a
+frontal, etc.; we will indicate but one detail in connection with these
+bones: it is the presence of a single condyle for the articulation of
+the occipital bone with the atlas. We also note the quadrate bone, which
+is situated on the lateral part of the cranium, is movable on this
+latter, and acts as an intermediary between it, the bones of the face,
+and the lower jaw. The quadrate bone is regarded as a detached portion
+of the temporal; on the signification of this we do not now propose to
+dwell.
+
+[Illustration: FIG. 65.--SKULL OF THE COCK: LEFT LATERAL SURFACE.
+
+1, Occipital bone; 2, parietal bone; 3, frontal bone; 4, ethmoid bone;
+5, cavity of the tympanum; 6, quadrate bone; 7, superior maxillary bone;
+8, malar bone; 9, nasal bone; 10, 10, intermaxillary bone; 11, nasal
+orifice; 12, os unguis or lachrymal bone; 13, inferior maxillary bone.]
+
+On the anterior portion of the face we find the nasal bones, which,
+articulating with the frontal on one side, circumscribe, on the other,
+the posterior border of the nares. The nasal bone of the one side is
+separated from that of the opposite by the intermaxillary or
+premaxillary bone, which forms the skeleton of the superior mandible.
+
+The superior maxillaries, which are rudimentary, are situated on the
+lateral parts, and prolonged backward by an osseous style which
+articulates with the quadrate bone; this styloid bone, the homologue of
+the malar, is designated by certain authors as the _jugal_ or
+_quadrato-jugal_ bone.
+
+It is with the quadrate bone also that the inferior maxillary
+articulates.
+
+
+
+
+CHAPTER II
+
+MYOLOGY
+
+
+The first point to decide in commencing this study is the order in which
+we shall consider the different muscles which we have to examine. It
+must not be forgotten that in the present work we compare the
+organization of animals with that of man, which we already know, and
+that it is on the construction of this latter that, in these studies,
+the thought must at each instant be carried back in order to establish
+this comparison. Now, the general tendency which we notice in our
+teaching of anatomy, when one regards the region of the trunk in the
+human figure (a living model or a figure in the round), is first to
+consider the anterior aspect. It is the latter that, for this reason, we
+study at the very beginning; we next deal with the posterior surface of
+the trunk, because it is opposite; lastly, the lateral surfaces, because
+they unite with the preceding surfaces, the one to the other.
+
+In studying an animal, it is usually by one of its lateral aspects that
+one first observes it; it is, in fact, by these aspects that it presents
+its greatest dimensions, and that the morphological characters as a
+whole can be more readily appreciated. Hence, possibly, the order of
+description adopted in most texts, or in the figures which accompany
+them. The first representation of the human figure as a whole, in a
+treatise on anatomy, represents the anterior aspect; the first view of
+the horse as a whole, in a treatise on veterinary anatomy, for example,
+is, on the other hand, a lateral view.
+
+We break with this latter custom, and, without taking into account the
+tendency above indicated, we will commence our analysis with the study
+of the aspect of the trunk, which corresponds to the anterior aspect of
+the same region in man.
+
+The first muscles usually presented for study to artists being the
+pectorals, it is their homologues that we will first describe here. We
+will afterwards describe the abdominal region, then the muscles which
+occupy the dorsal aspect of the trunk. With regard to the lateral
+surfaces, they will be found, by this fact alone, almost completely
+studied, since the muscles of the two preceding (back and abdomen),
+spreading out, so to speak, over them, contribute to their formation.
+Nothing further will remain but to incorporate with them the muscles of
+the shoulder; but these will be studied in connection with the anterior
+limbs, from which they cannot be separated.
+
+The neck, in man, may be considered in an isolated fashion, because, on
+account of its narrowness in proportion to the width of the shoulders,
+it is clearly differentiated from the trunk; for this reason we combine
+the study of it with that of the head. In animals, because of the
+absence or slight development of the clavicles, the neck is generally
+too much confounded with the region of the shoulders to make it
+legitimate to separate it from that region in too marked a fashion. It
+will, accordingly, be considered next.
+
+We will then undertake the study of the muscles of the limbs, and end
+with the myology of the head.
+
+
+THE MUSCLES OF THE TRUNK
+
+We shall divide them into muscles of the thorax, of the abdomen, and of
+the back.
+
+
+Muscles of the Thorax
+
+=The Pectoralis Major= (Fig. 66, 1, 2; Fig. 67, 3, 4; Fig. 68, 7; Fig.
+69, 10; Fig. 70, 11).--Further designated by the name of _superficial
+pectoral_, this muscle is described in treatises on veterinary anatomy
+as formed of two portions: an anterior one, called the _sterno-humeral_
+muscle; the other, situated below and behind the preceding, bearing the
+name of _sterno-aponeurotic_.
+
+It occupies the region of the breast, and, as a whole, it takes origin
+from the median portion of the sternum, from which it is directed
+towards the arm and forearm.
+
+The anterior portion (sterno-humeral muscle)--thick, forming an
+elevation under the skin, and really constituting the pectoral
+region--is directed downwards and outwards to be inserted into the
+anterior margin of the humerus--that is to say, to the ridge which
+limits in front the spiral groove of this bone.
+
+The other part (sterno-aponeurotic muscle) is situated more posteriorly,
+and corresponds to the region known in veterinary anatomy as the
+_inter-fore-limb space_, which is limited laterally on each side by the
+superior portion of the forearm, of which the point of junction with the
+trunk bears the name _ars_. Arising from the sternum, as we have above
+indicated, this portion is directed outwards, to be joined with the
+terminal aponeurosis of the sterno-humeral, and with that which covers
+the internal surface of the forearm.
+
+All things considered, the sterno-humeral muscle may be regarded as the
+representative of the upper fibres of the great pectoral of man, of
+which the attachments, owing to the more or less complete absence of the
+clavicle in the domestic mammals, the fibres must be concentrated on
+the sternum; the sterno-aponeurotic portion then representing the
+inferior fasciculæ of the same muscle.
+
+[Illustration: FIG. 66.--MYOLOGY OF THE HORSE: ANTERIOR ASPECT OF THE
+TRUNK.
+
+1, Pectoralis major (sterno-humeral); 2, pectoralis major
+(sterno-aponeurotic); 3, mastoido-humeralis; 4, point of the shoulder;
+5, sterno-mastoid or sterno-maxillary: 6, inferior portion of the
+platysma myoides of the neck, divided; 7, triceps cubiti; 8, brachialis
+anticus; 9, radialis (anterior extensor of the metacarpus); 10, scapular
+region.]
+
+The great pectoral muscle of one side is separated from that of the
+opposite side along the median line, and especially above and in front,
+by a groove which is more or less deep, according as the muscles are
+more or less developed. At the bottom of this groove, suggestive of that
+which exists in the corresponding region in man, is found, as in this
+latter, the median portion of the sternum.
+
+The preceding description particularly applies to the arrangement which
+the great pectoral presents in the horse; in other animals it is marked
+by some distinctive characters. In the pig, it is inserted into the
+sternum as far only as the level of the third costal cartilage; in the
+ox and sheep, it extends as far as the sixth; in the dog, it is
+attached to the two first sternal pieces only--that is to say, as far as
+the third costal cartilage. Moreover, in the latter, as in the cat, the
+two portions which we have indicated are less readily distinguished.
+
+The great pectoral, by its contraction, draws the fore-limb towards the
+middle line--that is to say, adducts it.
+
+=The Pectoralis Minor= (Fig. 67, 6; Fig. 68, 8; Fig. 69, 11; Fig. 70,
+12, 26).--This muscle, also called the _deep pectoral_, is, in animals,
+larger than the superficial pectoral, therefore certain authors prefer
+to give to this muscle and the preceding one the names of deep and
+superficial pectoral respectively. This nomenclature is evidently
+legitimate, and conforms more to reality, since it does not bring in the
+notion of dimensions which here is found in contradiction to
+nomenclature; but, in order to establish more clearly the parallelism
+with the corresponding muscles in man, we think it better, nevertheless,
+to give them the names by which it has been customary to designate them
+in connection with the latter.
+
+We will recall at the outset that the lesser pectoral muscle in man is
+completely covered by the great. In animals this is not the case; the
+lesser pectoral being very highly developed, projects beyond the great
+pectoral posteriorly, and occupies to a greater or less extent the
+inferior surface of the abdomen.
+
+It also consists of two parts: one anterior, which we designate by the
+name of _sterno-prescapular_; the other, posterior, bearing that of
+_sterno-humeral_.[20]
+
+  [20] This division of the pectorals certainly complicates the
+       nomenclature of these muscles; nevertheless, it introduces no
+       insuperable difficulty from the mnemonic point of view. But where
+       the study becomes less profitable, and comparison with the
+       corresponding muscles in man more complicated, is in adopting the
+       nomenclature of Bourgelat. Indeed, the great pectoral is
+       designated by this author the 'common muscle of the arm and
+       forearm,' while the lesser pectoral (or deep pectoral) is called
+       the 'great pectoral' in its sterno-trochinian and 'lesser
+       pectoral' in its sterno-prescapular portion. We do not consider
+       it necessary to give the other theories relative to the
+       homologies of these, notwithstanding the very real interest which
+       they present from the purely anatomical point of view, as they
+       have but few applications in the study of forms.
+
+The sterno-prescapular muscle, being covered by the sterno-humeral, has
+little interest for us. It arises from the sternum, and is directed
+towards the angle formed by the junction of the scapula and humerus;
+then it is reflected upwards and backwards, to terminate on the anterior
+margin of the shoulder by insertion into the aponeurosis, which covers
+the supraspinatus muscle.
+
+We can, especially in the horse after removal of the skin, recognise it,
+at the level of this region, in the interspace limited by the
+superficial muscles (Fig. 70, 26).
+
+In the dog and cat this portion of the muscle does not exist. The other
+division of the muscle, the sterno-trochinian, is more interesting. It
+arises from the abdominal aponeurosis and the posterior part of the
+sternum; hence it passes forward, turns under the superficial pectoral,
+and is inserted into the lesser tuberosity (trochin) of the humerus.
+
+In the pig, dog, and cat, it is inserted into the greater tuberosity
+(trochiter) of the bone of the arm.
+
+The superior border of this muscle is in relation with a superficial
+vein, which is distinctly visible in the horse--the subcutaneous
+thoracic vein, which in this animal is called the vein of the spur.
+
+The sterno-humeral muscle, in contracting, draws the shoulder and the
+whole anterior limb backwards.
+
+=Serratus Magnus= (Fig. 67, 2; Fig. 69, 8; Fig. 70, 9).--This muscle,
+which is situated on the lateral aspect of the thorax, is covered to a
+considerable extent by the shoulder, the posterior muscular mass of the
+arm, and by the great dorsal muscle.
+
+It arises by digitations from the external surface of the dorsal
+vertebræ; from the first eight in the horse, ox, and dog.
+
+[Illustration: FIG. 67.--MYOLOGY OF THE HORSE: INFERIOR ASPECT OF THE
+TRUNK.
+
+1, Anterior extremity of the sternum; 2, point of the shoulder and
+inferior portion of the mastoido-humeral muscle; 3, pectoralis major
+(sterno-humeral); 4, pectoralis major (sterno-aponeurotic); 5, point of
+the elbow; 6, pectoralis minor (sterno-trochinian); 7, serratus magnus;
+8, external oblique; 9, sheath of the rectus abdominis; 10, linea alba;
+11, the umbilicus; 12, external oblique divided in order to expose the
+rectus abdominis; 13, rectus abdominis.]
+
+The muscular bundles, converging as they proceed, towards the scapula,
+pass under this bone, to be inserted into the superior portion of the
+subscapular fossa, near the spinal border. The inferior portion of its
+posterior digitations is visible in the ox and in the horse; these
+digitations are less visible in the pig. They are not seen at all in the
+dog (Fig. 68) or cat, for in these animals the great dorsal muscle
+covers them completely.
+
+The great serratus muscle, by the position which it occupies and the
+arrangement that it presents, forms with the corresponding muscle of the
+opposite side a sort of girth, which supports the thorax, and at the
+same time helps to fix the scapula against the latter.
+
+When it contracts, in taking its fixed point at the ribs, it draws the
+superior portion of the scapula downwards and backwards in such a way
+that this bone has its inferior angle directed forwards and upwards. If
+it takes its fixed point at the shoulder, it then acts on the ribs,
+raises them, and so becomes a muscle of inspiration.
+
+Because of the connections of the serratus magnus with the levator
+anguli scapulæ, some authors consider it as united with the latter. But
+as the latter muscle is visible only in the region of the neck (see p.
+157), and as it is separately described in man, we prefer to distinguish
+them from one another. We shall recall the connections to which we have
+just made allusion when describing the cervical region.
+
+
+Muscles of the Abdomen
+
+The abdominal wall is, as in man, formed by four large muscles: the
+external oblique, the internal oblique, and the transversalis, which
+form the lateral walls, and the rectus abdominis, situated on each side
+of the middle line of the abdomen. This latter, because of the general
+direction of the trunk in quadrupeds, has its superficial surface
+directed downwards.
+
+The arrangement of these muscles closely corresponds to that which we
+find in the human species.
+
+=The External Oblique Muscle= (Fig. 67, 8, 12; Fig. 68, 5; Fig. 69, 9;
+Fig. 70, 10).--This muscle arises, by digitations, from a number of
+ribs, which varies according to the species, the number of the ribs
+being itself variable for each of them, as we pointed out in connection
+with the osteology of the thorax. Indeed, the great oblique arises from
+the eight or nine posterior ribs in the dog and the ox, and from the
+thirteen or fourteen posterior in the horse. It is attached, besides, to
+the dorso-lumbar aponeurosis.
+
+These attachments are arranged in a line directed obliquely upwards and
+backwards, and the first digitations--that is to say, the most anterior
+ones--dovetail with the posterior digitations of origin of the great
+serratus muscle.
+
+The fleshy fibres are directed downwards and backwards, and terminate in
+an aponeurosis which covers the inferior aspect of the abdomen, and
+proceeds to form the linea alba by joining with that of the muscle of
+the opposite side, and also to be inserted into the crural arch.
+
+This aponeurosis of the external oblique is covered by an expansion of
+elastic fibrous tissue, which doubles it externally, and which is known
+as the _abdominal tunic_. This latter is further developed as the organs
+of the digestive apparatus are more voluminous, and their weight,
+consequently, more considerable. For this reason, in the large
+herbivora, as the ox and the horse, this tunic is extremely thick,
+whereas in the pig, cat, and dog it is, on the contrary, reduced to a
+simple membrane. Indeed, in these latter, the abdominal viscera being
+less developed, the inferior wall of the abdomen does not require so
+strong a fibrous apparatus for supporting them. The great oblique, when
+it contracts, compresses the abdominal viscera in all circumstances
+under which this compression is necessary; it also acts as a flexor of
+the vertebral column.
+
+=The Internal Oblique Muscle.=--This muscle, which is covered by the
+preceding, arises from the anterior superior iliac spine (external angle
+in ruminants and solipeds) and the neighbouring parts. From this origin
+its muscular fibres, the general direction of which is opposite to that
+of the fibres of the external oblique, diverging, proceed to terminate
+in an aponeurosis, which contributes to the formation of the _linea
+alba_, and to be attached superiorly to the internal surface of the last
+costal cartilages. It has the same action as the great oblique. What it
+presents of special interest is the detail of form which it determines
+in the region of the flank; this detail is _the cord of the flank_. It
+is characterized by an elongated prominence which, starting from the
+iliac spine, is directed obliquely downwards and forwards, to terminate
+near the cartilaginous border of the false ribs.
+
+Often very apparent in the ox, and still more so in the cow, the cord in
+question contrasts with the depression which surmounts it; this
+depression is situated below the costiform processes of the lumbar
+vertebræ, and is called the _hollow of the flank_. It is so much the
+more marked as the mass of the intestinal viscera is of greater weight.
+
+We sometimes meet with a case of the presence of this hollow in the
+horse. But when in the latter, the flank is well formed, the hollow is
+scarcely visible, and the cord but slightly prominent. It is only in
+emaciated subjects that these details are found clearly marked.
+
+=Transversalis Abdominis.=--This muscle being deeply situated does not
+present any interest for us. We will, however, point out, in order to
+complete the series of muscles which form the abdominal wall, that the
+direction of its fibres is transverse, and that they extend from the
+internal surface of the cartilages of the false ribs, and the costiform
+processes of the lumbar vertebræ to the _linea alba_.
+
+=The Rectus Abdominis= (Fig. 67, 13; Fig. 68, 6).--This muscle,
+enclosed, as it is in man, in a fibrous sheath (Fig. 67, 9) formed by
+the aponeuroses of the lateral muscles of the abdomen, is a long and
+wide fleshy band, which, as in the human species, reaches from the
+thorax to the pubis.
+
+What distinguishes it in quadrupeds is that there are costal attachments
+which extend further on the sternal surface of the thorax, and the
+number of its aponeurotic insertions, which, in general, is more
+considerable. These are, indeed, six or seven in number in the pig and
+in ruminants, and about ten in the horse.
+
+It is true that we may find but three in the cat and dog; still, we
+often find as many as six. These intersections are not marked on their
+exterior by transverse grooves, such as we find in the human species in
+individuals with delicate skin and whose adipose tissue is not very much
+developed.
+
+The rectus abdominis is covered, in its anterior portion, by the
+sterno-trochinian muscle (posterior segment of the small pectoral). In
+contracting, this muscle brings the chest nearer the pelvis, and as a
+result flexes the vertebral column. It also contributes to the
+compression of the abdominal viscera.
+
+=Pyramidalis Abdominis.=--This unimportant little muscle, which in man
+is situated at the lower part of the abdomen, extends from the pubis to
+the _linea alba_. It is not present in the domestic animals.
+
+We consider it interesting, however, to point out, although the fact is
+not a very useful one as regards external form, that this muscle is
+distinctly developed in marsupials.
+
+We know that in the opossum, the kangaroo, and the phalanger fox, the
+young are brought forth in an entirely incomplete state of development,
+and that, during a certain period, they are obliged to lodge in a pouch
+which is placed at the lower part of the abdomen of the mother. Now,
+this pouch contains the mammary glands; but the young, being too feeble
+to exercise the requisite suction, the pyramidal muscles come to their
+assistance. These muscles, in contracting, approximate to one another
+two bones which are placed above the pubis, the (so-called) marsupial
+bones (see Fig. 80); by their approximation the bones in question, which
+are placed behind and on the outer side of the mammary glands, compress
+the latter, and thus is brought about the result which the little ones,
+on account of their feebleness, would, without that intervention, be
+incapable of obtaining for themselves.
+
+
+Muscles of the Back
+
+=Trapezius= (Fig. 68, 1, 2; Fig. 69, 1, 2; Fig. 70, 1, 2).--This muscle,
+more or less well developed, according to the species, is divided into
+two portions, of which the names indicate the respective situations--a
+cervical and a dorsal.
+
+These two parts, considered in the order in which we find them, take
+their origin from the superior cervical ligament and from the spinous
+processes of the first dorsal vertebræ. From these different points the
+fibres are directed towards the shoulder; the anterior are,
+consequently, oblique downwards and backwards, and the posterior are
+directed downwards and forwards. They are inserted into the scapula in
+the following manner: the fibres of the dorsal portion are attached to
+the tuberosity of the spine; those of the cervical region are also fixed
+into the same spine, but into a considerably larger surface.
+
+The cervical portion occupies, in the region of the neck, an area
+relatively smaller than the corresponding portion of the trapezius in
+man. This diminished degree of development results from the absence,
+complete, or nearly so, of the clavicle in the animals which we are now
+considering. We remember, that the trapezius of man is partly inserted
+into the clavicle, and the disappearance of this latter cannot fail to
+bring modifications in the general disposition of the corresponding
+portion of the muscle. There results a disconnection of this latter, and
+it becomes united to other muscular fibres to form a muscle with which
+we shall soon have to deal--the mastoido-humeral (see p. 150).
+
+As specific differences we should add that the trapezius occupies a more
+or less extensive portion of the median and superior regions of the
+neck; terminating at a considerable distance from the head in the dog
+and horse, it, on the contrary, approaches it in the pig and in
+ruminants. The cervical portion, when it contracts, draws the scapula
+upwards and forwards, the dorsal portion draws it upwards and backwards.
+When the trapezius acts as a whole the scapula is raised.
+
+[Illustration: FIG. 68.--MYOLOGY OF THE DOG: SUPERFICIAL LAYER OF
+MUSCLES.
+
+1, Trapezius, cervical portion; 2, trapezius, dorsal portion; 3,
+superior outline of the scapula; 4, latissimus dorsi; 5, external
+oblique muscle; 6, rectus abdominis; 7, pectoralis major of the right
+side; 8, pectoralis minor (sterno-trochinian); 9, 9, mastoido humeral
+muscle; 10, tendinous intersection, at the level of which is found a
+rudimentary clavicle; 11, sterno-mastoid muscle; 12, infrahyoid muscles;
+13, omo-tracheal or acromio-tracheal muscle; 14, splenius; 15, levator
+anguli scapulæ; 16, deltoid muscle, spinal portion; 17, deltoid,
+acromial portion; 18, superior extremity of the humerus; 19,
+supraspinatus; 20, infraspinatus; 21, biceps cubiti; 22, brachialis
+anticus; 23, triceps cubiti, long head; 24, triceps cubiti, external
+head; 25, olecranon process; 26, radialis (anterior extensor of the
+metacarpus); 27, iliac crest; 28, gluteus maximus; 29, gluteus medius;
+30, biceps cruris; 31, semitendinosus; 32, semi-membranosus; 33,
+gastrocnemius; 34, tensor of the fascia lata; 35, sartorius; 36, fascia
+lata drawn up by the triceps; 37, the patella or knee-cap; 38,
+ischio-coccygeal muscle; 39, superior sacro-coccygeal; 40, lateral
+sacro-coccygeal; 41, inferior sacro-coccygeal.]
+
+=The Latissimus Dorsi= (Fig. 68, 4; Fig. 69, 5; Fig. 70, 5).--This
+muscle arises by an aponeurosis, the so-called dorso-lumbar aponeurosis,
+from the spinous processes of the last dorsal vertebræ (the seven last
+in the dog, fourteen or fifteen last in the horse), from the spinous
+processes of the lumbar vertebræ, and from the last ribs. Its fleshy
+fibres are directed downwards and forwards, being more oblique in
+direction posteriorly, and pass on the inner side of the posterior
+muscular mass of the arm, to be inserted into the internal lip of the
+bicipital groove of the humerus, or, a little lower down, on the median
+portion of the internal surface of the same bone. This latter mode of
+insertion is met with in the horse and the ox.
+
+The anterior fibres cover the posterior angle of the scapula (as in man,
+where the corresponding angle, but in this case inferior, is covered by
+the same muscle), and, a little higher up, are in their turn concealed
+by a portion of the dorsal fibres of the trapezius. It covers, to a
+greater or less extent, the great serratus muscle. These relations are
+similar to those found in the human species.
+
+We find that the fleshy fibres of the great dorsal are prolonged more or
+less backwards if we examine this muscle in the dog, the ox, the pig,
+and the horse. Indeed, the fibres reach to the thirteenth rib in the dog
+and the cat (that is to say, the last rib), the eleventh in the ox,
+tenth in the pig, and twelfth only in the horse. We say 'only' in
+connection with this last because it is necessary to remember that the
+ribs are eighteen in number on each side of the thorax of this animal,
+and that, accordingly, the fleshy fibres of the great dorsal muscle are,
+relatively, of small extent.
+
+When this muscle contracts it flexes the humerus upon the scapula, and
+helps to draw the whole of the anterior limb backwards and upwards.
+
+There is a muscular fasciculus which, because of its relations with the
+muscle we have just been studying, is known as the _supplementary muscle
+of the latissimus dorsi_. But as, on the other hand, this fasciculus is
+in relation with the triceps, we shall in preference consider it in
+relation with this latter (see p. 173).
+
+[Illustration: FIG. 69.--MYOLOGY OF THE OX: SUPERFICIAL LAYER OF
+MUSCLES.
+
+1, Trapezius, cervical portion; 2, trapezius, dorsal portion; 3, outline
+of the scapula; 4, spine of the scapula; 5, latissimus dorsi; 6, small
+posterior serratus; 7, prominence caused by the costiform processes of
+the lumbar vertebræ; 8, serratus magnus; 9, external oblique; 10,
+pectoralis major (sterno-humeral); 11, mastoido-humeralis; 12, atlas;
+13, atlas; 14, parotid gland; 15, sterno-mastoid muscle; 16, infrahyoid
+muscles; 17, omo-trachelian or acromio-trachelian muscle; 18, deltoid;
+19, brachialis anticus; 20, triceps, long head; 21, triceps, external
+head; 22, olecranon; 23, radialis (anterior extensor of the metacarpus);
+24, anterior iliac spine; 25, gluteus maximus; 26, gluteus medius; 27,
+biceps cruris; 28, semitendinosus; 29, gastrocnemius; 30, tensor of the
+fascia lata; 31, fascia lata covering the triceps of the thigh; 32,
+patella; 33, ischio-coccygeal muscle; 34, superior ischio-coccygeal; 35,
+lateral ischio-coccygeal; 36, inferior ischio-coccygeal.]
+
+The aponeurosis by which the great dorsal arises from the vertebral
+column covers, as in man, the muscles which occupy the grooves situated
+on each side of the spinous processes--the spinal muscles or common
+muscular mass, if we regard them as a whole (Fig. 70, 7); the
+sacro-lumbar and the long dorsal muscles covering the transverse spinal,
+if we consider them as distinct.
+
+It would be superfluous to enter here into a detailed examination of
+these muscles.
+
+If they are but little developed the spinous processes become prominent
+under the skin; if they are more so they may by their thickness project
+beyond the level of these processes, and these latter thus come to lie
+in a groove more or less marked, which, on account of the division which
+is determined by its presence, has caused the regions which it occupies
+to be designated by the names _double back_ and _double loins_.
+
+The muscles are extensors of the vertebral column.
+
+Under the aponeurosis of the great dorsal muscle there is found in man
+another muscle, the serratus posticus inferior, which, on account of
+being deeply placed and its slight thickness, offers nothing of interest
+in connection with the study of external form. It arises from the
+spinous processes of the three last dorsal vertebræ and those of the
+three first lumbar; it then passes upwards and outwards, and divides
+into four digitations, to be inserted into the inferior borders of the
+four last ribs. We repeat that it is covered by the great dorsal muscle.
+
+In the pig, ox, and horse, which have this latter muscle less developed
+in its posterior portion, the same small serratus muscle, known as the
+_posterior serratus_, is visible in the superficial layer of muscles
+(Fig. 69, 6; Fig. 70, 6). The number of its digitations is more or less
+considerable according to the species examined.
+
+=The Rhomboid Muscle= (Fig. 70, 21).--In order to make intelligible the
+position of the rhomboid in the superficial layer in quadrupeds, it
+appears to us necessary to recall the anatomical characters of the
+muscle as found in man. The rhomboid arises from the inferior portion of
+the posterior cervical ligament, from the spinous process of the seventh
+cervical vertebræ and the four or five upper dorsal; thence passing
+obliquely downwards and outwards, it is inserted into the spinal border
+of the scapula, into the portion of this border which is situated below
+the spine; it sometimes extends to the middle of the interval which
+separates this latter from the superior internal angle of the same bone.
+
+The portion of the muscle which arises from the cervical ligament and
+the seventh cervical vertebra is often separated from the lower portion
+by a cellular interspace. For this cause some anatomists have described
+the rhomboid as consisting of two parts--the superior or small rhomboid
+and the inferior or large rhomboid, on account of the position occupied
+by each, and of their difference in volume.
+
+This muscle can only be seen in the region of the back, in the space
+limited externally by the spinal border of the scapula, below by the
+latissimus dorsi, and internally by the trapezius, which covers it in
+the rest of its extent. It is not in this space that it is seen in
+certain quadrupeds. As we pointed out in the section on osteology, the
+spinal border of the scapula is short, and it seems to be due to this
+limitation in length that the trapezius and the latissimus dorsi muscle
+are, at this level, in contact the one with the other in such a way that
+they fill up the interval in which the rhomboid is seen in man.
+
+In the horse we can partly see it in the superficial muscular layer, but
+in the region of the neck only, at the superior border of the shoulder.
+Indeed, as we have already pointed out, the trapezius does not reach the
+occipital protuberance; for this reason a part of the anterior portion
+of the rhomboid may be seen--that is, the portion which corresponds to
+the superior part of the human muscle.
+
+But whether it be covered by the trapezius, or, as we find in the cat
+and dog, by the _mastoido-humeral muscle_ (see p. 150), which is very
+broad in this region, we do not the less recognise its presence; and in
+the horse and ox, in particular, it forms an elongated prominence
+beginning at the level of the scapula, and tapering as it ascends,
+towards the posterior part of the head.
+
+[Illustration: FIG. 70.--MYOLOGY OF THE HORSE: SUPERFICIAL LAYER OF
+MUSCLES.
+
+1, Trapezius, cervical portion; 2, trapezius, dorsal portion; 3,
+superior outline of the scapula; 4, spine of the scapula; 5,
+latissimus dorsi muscle; 6, small posterior serratus; 7, spinal muscles,
+or common muscular mass; 8, ribs; 9, serratus magnus; 10, external
+oblique; 11, pectoralis major (sterno-humeral); 12, pectoralis
+minor (sterno-trochinian); 13, atlas; 14, parotid gland; 15,
+mastoido-humeralis; 16, point of the arm; 17, sterno-mastoid, or
+sterno-maxillary; 18, jugular groove; 19, infrahyoid muscles; 20,
+omo-trachelian muscle; 21, rhomboid; 22, splenius; 23, levator anguli
+scapulæ; 24, deltoid; 25, supraspinatus; 26, terminal part of the
+sterno-prescapular, a portion of the small pectoral muscle; 27,
+brachialis anticus; 28, triceps cubiti, middle or long head; 29, triceps
+cubiti, external head; 30, olecranon; 31, radial extensor (anterior
+extensor of the metacarpus); 32, anterior iliac spine; 33, anterior
+portion of the gluteus maximus--the aponeurosis of the muscle has been
+divided in order to expose the gluteus medius; 34, posterior portion of
+the gluteus maximus; 35, gluteus medius; 36, biceps cruris; 37,
+semitendinosus; 38, point of the buttock; 39, gastrocnemius; 40, tensor
+of the fascia lata; 41, triceps cruris; 42, ischio-coccygeal muscle; 43,
+superior sacro-coccygeal; 44, lateral sacro-coccygeal; 45, inferior
+sacro-coccygeal.]
+
+Its origins are similar to those which we have already described in the
+human rhomboid. It arises from the cervical ligament and the spinous
+processes of the foremost dorsal vertebræ; its fibres converge and pass
+to the scapula, to be inserted into its superior or spinal border, or
+into the internal surface of the cartilage of prolongation.
+
+It assists in keeping the scapula applied to the thoracic cage, and when
+it contracts, draws the scapula upwards and forwards.
+
+Taking its fixed point at the scapula, it acts on the neck by its
+anterior fibres, and extends it.
+
+We shall soon have occasion to mention this muscle again, in connection
+with the study of the muscles of the neck.
+
+=The Cutaneous Muscle of the Trunk= (Fig. 71).--Immediately beneath the
+skin which covers the neck, shoulders, and trunk is found a vast
+cutaneous muscle, analogous to that which, in the human species, exists
+only in the cervical region.
+
+This thin muscle, whose function is to move the skin which strongly
+adheres to it, and in this way to remove from it material causes of
+irritation (insects, for example), is of considerable thickness in the
+region of the trunk; where it constitutes what certain authors have
+designated by the name of _panniculus carnosus_. In this region it
+extends from the posterior border of the shoulder to the thigh, and, in
+the vertical direction, from the apices of the spinous process of the
+dorso-lumbar vertebræ to the median line of the abdomen.
+
+Arising above from the supraspinous ligament of the dorso-lumbar and
+sacral regions (except in the carnivora; see below) by an aponeurosis
+which, posteriorly, covers the muscles of the hind-limbs, its fibres are
+directed to the elbow, on which they are arranged in two layers: a
+superficial, which becomes continuous with the panniculus muscle of the
+shoulder; and a deep, which passes on the inner side of the shoulder to
+be inserted into the internal surface of the humerus; this latter exists
+only in the dog and cat.
+
+The most inferior fibres, behind, at the level of the knee-cap form a
+triangular process which in the horse receives the name of the _stifle
+fold_, from the name veterinarians give to the region of the
+articulation of the knee. This fold of skin, which commences on the
+antero-internal surface of this region, is directed upwards, and then
+forwards, to end by gradually disappearing over the corresponding part
+of the abdomen.
+
+[Illustration: FIG. 71.--MYOLOGY OF THE HORSE: PANNICULUS MUSCLE OF THE
+TRUNK.]
+
+In the same animal the muscular fibres of the panniculus of the trunk
+arise along a line which connects the stifle-joint to the withers, a
+line which is, consequently, oblique upwards and forwards. Now, as the
+fleshy layer is thicker than the aponeurosis, the result is that the
+mode of constitution of this muscle can be recognised under the skin.
+Indeed, we can see in some animals, occasionally very distinctly, a
+slight elevation starting from the region of the abdomen in the
+neighbourhood of the knee, and thence directed obliquely upwards and
+forwards. This elevation is produced by the fleshy portion of the
+panniculus.
+
+In the carnivora, the panniculus of the trunk is not attached to the
+supraspinous ligament; it is blended with the same muscle of the
+opposite side, passing over the spinous region of the vertebral column.
+
+From this arrangement results a great mobility of the skin which covers
+the back. Further, it explains why it is possible to lift up this skin
+along with the panniculus which it covers, and to which it adheres,
+throughout the whole extent of the dorso-lumbar column. As we pointed
+out above, there is also a panniculus muscle of the shoulder and one of
+the neck. We will deal with them when treating of the regions to which
+those muscles belong.
+
+
+The Coccygeal Region
+
+As a sequel to the study of the muscles of the region of the trunk very
+naturally comes the description of those which, belonging to the region
+of the coccyx, are destined for the movements of the caudal appendix, of
+which this latter constitutes the skeleton. The muscles may not seem to
+be of much importance with regard to external form, but, as they form
+part of the superficial muscular layer, and as the mass of each is
+seen in the form of the tail in some animals (the lion, for example),
+they merit our attention for a moment. A few lines will suffice to
+give an idea of them. They are: the _ischio-coccygeal_, _superior
+sacro-coccygeal_, _lateral sacro-coccygeal_, and _inferior
+sacro-coccygeal_.
+
+=The Ischio-coccygeal= (Fig. 18, 38; Fig. 69, 33; Fig. 70, 42).--This
+muscle, triangular in shape, better developed in the carnivora than in
+the horse, arises from the spine of the ischium, or from the
+supracotyloid crest, which replaces this latter in the solipeds and the
+ruminants. Thence its fleshy mass is directed upwards, expanding as it
+proceeds to be inserted into the transverse processes of the first two
+coccygeal vertebræ after insinuating itself between two of the following
+muscles, the lateral and inferior sacro-coccygeal.
+
+In the dog and cat, the muscle is in great part covered by the great
+gluteal. In the ox, by a peculiar arrangement of the corresponding
+region of the muscles of the thigh--an arrangement which we will examine
+in connection with the study of the latter--it is more exposed than in
+the horse, and gives origin to an outline which corresponds to its
+general form in the region situated immediately below the root of the
+tail.
+
+It is a depressor of the whole caudal appendix.
+
+=The Superior Sacro-coccygeal= (Fig. 68, 39; Fig. 69, 34; Fig. 70,
+43).--The fasciculi which form this muscle arise from the crest of the
+sacrum, and proceed thence to end successively on the coccygeal
+vertebræ. It is in contact in the middle line with the corresponding
+muscle of the opposite side.
+
+It raises the tail and inclines it laterally; if the muscle of one side
+contracts at the same time as that of the other the tail is elevated
+directly.
+
+=The Lateral Sacro-coccygeal= (Fig. 68, 40; Fig. 69, 35; Fig. 70,
+44).--Situated on the lateral part of the caudal region, this muscle
+arises, in the dog, from the internal border of the iliac bone and the
+external border of the sacrum; in the horse, it arises from the crest of
+the sacrum. It is inserted into the coccygeal vertebræ.
+
+It produces lateral movement of the tail.
+
+=The Inferior Sacro-coccygeal= (Fig. 68, 41; Fig. 69, 36; Fig. 70,
+43).--This muscle, which is fairly thick, arises from the inferior
+surface of the sacrum and the corresponding surface of the sacro-sciatic
+ligament; it is inserted into the coccygeal vertebræ.
+
+It depresses the caudal appendix.
+
+
+Muscles of the Neck
+
+=Mastoido-humeralis= (Fig. 66, 3; Fig. 68, 9, 9, 10; Fig. 69, 12; Fig.
+70, 15).--One of the most important muscles of the region of the neck in
+man is the sterno-cleido mastoid. We recollect that, in its inferior
+part, it is divided into two bundles, one of which arises from the
+manubrium of the sternum, and the other from the inner third of the
+clavicle, whence the denominations of the _sternal_ portion and
+_clavicular_ portion. The muscle formed by the union of these two
+portions is then directed obliquely outwards, backwards, and upwards, to
+be inserted into the mastoid process of the temporal bone and the two
+external thirds of the superior curved line of the occipital bone.
+
+Now, the animals which we are here considering have but a rudimentary
+clavicle or are entirely without it. From the absence of this item of
+the skeleton there necessarily result modifications in the arrangement
+of the muscles of this region, which we must at the very outset explain,
+before undertaking the special study of the muscle which is the subject
+of the present paragraph.
+
+Let us suppose, for the more definite arrangement of our ideas, that the
+clavicle is altogether absent, although we do find it in a rudimentary
+state in some animals and completely developed in others (marmot, bat),
+and we will proceed to indicate what this absence determines.
+
+The great pectoral muscle in man arises in part from the clavicle; this
+origin not being possible in animals which have no clavicle, its
+attachments, as we have already seen, are concentrated on the sternum.
+The trapezius in man similarly arises in part from the clavicle; for the
+reasons above indicated its clavicular fasciculi cannot exist in
+distinct form in the animals which have no clavicle.
+
+The sterno-cleido mastoid, whose inferior attachments we mentioned
+above, cannot have a clavicular portion.
+
+It is the same in the case of the deltoid, which, we know, arises in
+part from the anterior bone of the shoulder.
+
+Of the four muscles which have partial clavicular origins in man, two
+are known to us in connection with animals--the great pectoral and the
+trapezius. What has become of the other two, the sterno-cleido mastoid
+and the deltoid?
+
+It is this which we now proceed to investigate. After a fashion
+simple enough, but which it is necessary to describe, the clavicular
+fasciculi of the trapezius and the corresponding fasciculi of the
+sterno-cleido mastoid are united the one to the other; the portion
+of the deltoid which in man arises from the clavicle, by reason of the
+absence of this latter, is also combined with the fleshy mass formed by
+the preceding muscles. From this fusion results the muscle known as the
+mastoido-humeral. This muscle, which consists of a long fleshy band
+situated on the lateral aspect of the neck, takes its origin, as a
+general rule, from the posterior surface of the skull and the upper part
+of the neck, from which it passes obliquely downwards and backwards,
+covering the scapulo-humeral angle--that is, the region known as the
+point of the shoulder or arm--and is inserted into the anterior border
+of the humerus, the border which, limiting anteriorly the musculo-spiral
+groove, forms a continuation of the deltoid impression. On account of
+the regions with which it is related, Bourgelat named this muscle _the
+muscle common to the head, neck, and arm_.
+
+It is at the level of the scapulo-humeral angle that the vestiges of the
+clavicle are found.
+
+This bone is represented in some animals--the pig, ox, and horse--by a
+single tendinous intersection, more or less apparent, which extends
+transversely from the scapula to the anterior extremity of the sternum.
+In the dog and the cat, we find, besides, on the deep surface of the
+muscle and at the level of this tendinous intersection, the rudiment of
+the clavicle of which we made mention in the section on Osteology (see
+p. 25).
+
+It is beneath the intersection, the existence of which we have just
+pointed out, that is found that portion of the mastoido-humeral muscle
+which corresponds to the clavicular fasciculi of the deltoid; that
+portion which is situated above the intersection corresponds to the
+clavicular fibres of the sterno-cleido-mastoid and of the trapezius.
+
+The mastoido-humeral presents certain varieties in different animals.
+
+In the dog and the cat, this muscle, which is blended above with the
+sterno-mastoid (see p. 153), to be inserted with it into the mastoid
+process and the mastoid crest, covers the neck for a considerable extent
+from the superior curved line of the occipital bone to which it is
+attached, to the trapezius with which it unites posteriorly, but from
+which it separates below. Between these two extreme points of its
+superior portion it is attached to the cervical ligament.
+
+In the pig and in ruminants, in which the trapezius approaches more
+closely to the head, the mastoido-humeral occupies, in consequence, a
+less extent of the cervical region.
+
+In the horse, the mastoido-humeral neither covers the neck nor joins the
+trapezius; indeed, we have already shown that it is separated by a
+considerable distance from the head. In the limited interval between
+these two muscles a part of the rhomboid and parts of other muscles are
+seen with which we shall soon be occupied.
+
+This muscle, as regards the horse, is described by some anatomists as
+consisting of two parts: one anterior, or superficial; the other
+posterior, or deep. In reality, the first only corresponds to the
+mastoido-humeral, which we are considering; the posterior may be more
+exactly regarded as representing a special muscle of quadrupeds, but
+which is here a little deformed, the _omo-trachelian_ (see p. 155).
+
+When the mastoido-humeral contracts, taking its fixed point above, it
+acts as an extensor of the humerus, and carries the entire fore-limb
+forwards. If it takes its fixed point below--that is to say, at the
+humerus--it inclines the head and neck to its own side. If it contracts
+at the same time as the mastoido-humeral of the opposite side, then the
+head and the neck are carried into the position of extension.
+
+=The Sterno-mastoid= (Fig. 66, 5; Fig. 68, 11; Fig. 69, 15;
+Fig. 70, 17).--Having described the clavicular portion of the
+sterno-cleido-mastoid in connection with the mastoido-humeral, because
+it forms a part of the latter, we have, in order to complete the
+homologies of this muscle, to study now that which corresponds to its
+sternal portion. This is the _sterno-mastoid_ muscle. In all the
+quadrupeds with which we are here concerned this muscle arises from the
+anterior extremity of the sternum; narrow and elongated in form, it
+passes towards the head in a direction parallel to the anterior border
+of the mastoido-humeral, from which it is separated by an interspace
+which, along its whole length, lodges superficially the jugular vein;
+hence the name of _jugular groove_, which is given to this part of the
+neck (Fig. 10, 18).
+
+It is inserted, in the case of the dog and cat, into the mastoid
+process, where it is united with the mastoido-humeral; in the ox it is
+divided into two portions--one which goes to the base of the occipital
+bone, the other passing in front of the masseter is by the medium of
+the aponeurosis of this latter attached to the zygomatic crest. This
+latter part is considered by some writers as forming a portion of the
+panniculus muscle of the neck.
+
+In the horse it is attached to the angle of the lower jaw by a tendon,
+which an aponeurosis that passes under the parotid gland binds to the
+mastoido-humeral muscle and the mastoid process.
+
+By reason of this insertion into the jaw, in the case of the solipeds,
+this muscle is further named the _sterno-maxillary_.
+
+When it contracts, it flexes the head, and inclines it laterally. This
+movement is changed to direct flexion when the two sterno-mastoid
+muscles contract simultaneously.
+
+In man, the sterno-cleido-mastoid and the trapezius leave a triangular
+space between them, which, being limited inferiorly by the middle third
+of the clavicle, is known as the supraclavicular region; this region,
+being depressed, especially in its inferior part, has also been given
+the name of supraclavicular fossa--popularly called the '_salt-cellar_.'
+
+The muscles which form the floor of this region, passing from above
+downwards, are: a very small portion of the complexus, splenius, levator
+anguli scapulæ, posterior scalenus, and anterior scalenus; then,
+crossing these latter, and most superficial, is the omo-hyoid muscle.
+
+An analogous region, but of only slight depth, exists in quadrupeds; its
+borders are formed by the mastoido-humeral and trapezius muscles.
+
+It is not limited below by the clavicle--we know, indeed, that this, or
+the intersection which represents it, belongs to the mastoido-humeral
+muscle--but by the inferior portion of the spine of the scapula.
+
+It is of greater or less extent according to the species considered.
+
+In the dog, cat, pig, and ox, it is narrow, for the muscles which bound
+it approach one another pretty closely. It has, as in man, the form of a
+triangle, with the apex above. In the horse it is much broader, and,
+contrary to the arrangement which it presents in the human species, the
+widest part is directed upwards.
+
+The muscles which we find there are, consequently, more or less
+numerous. In the dog and cat they are: a portion of a muscle which we do
+not normally meet with in man--the _omo-trachelian_--then in a
+decreasing extent: supraspinatus, levator anguli scapulæ and splenius.
+
+In the pig: the omo-trachelian, supraspinatus, and the terminal portion
+of the sterno-prescapular--the anterior part of the lesser or deep
+pectoral muscle.
+
+In the ox: the omo-trachelian only.
+
+But in the horse we find the omo-trachelian, the supraspinatus, and the
+terminal extremity of the sterno-prescapular; then in a larger extent of
+area the levator anguli scapulæ and the splenius; and, finally, the
+anterior portion of the rhomboid.
+
+Among the muscles which we have just enumerated are some that we have
+already studied; these are the sterno-prescapular and the rhomboid. We
+will examine the supraspinatus muscle in connection with the region of
+the shoulder.
+
+As to the scaleni muscles and the complexus, they are deeply situated,
+whereas the omo-hyoid is visible in the anterior region of the neck
+only.
+
+There remain for us, accordingly, to examine, at the present juncture,
+but the omo-trachelian, levator anguli scapulæ, and splenius muscles.
+
+=The Omo-trachelian Muscle= (Fig. 68, 13; Fig. 69, 17; Fig. 70,
+20).--Also called the _acromio-trachelian_, _levator ventri
+scapulæ_,[21] the _angulo-ventral muscle_, and the
+_transverso-scapular_,[22] etc., this muscle is described by some
+hippotomists as belonging to the mastoido-humeral, of which it then
+forms its posterior or deep portion (see p. 153).
+
+  [21] Ventri, because inserted into the inferior part of the spine of
+       the scapula, towards the acromion--that is, on the ventral
+       side--by contrast with the trapezius, which is attached higher up
+       (dorsal side) on the same process.
+
+  [22] Among the many names given to this muscle, Arloing and Lesbre
+       recommend the adoption of the name 'transverse scapular' given by
+       Straus-Durckheim, or 'transverse of the shoulder' (Arloing and
+       Lesbre, 'Suggestions for the Reform of Veterinarian Muscular
+       Nomenclature,' Lyons, 1898).
+
+The omo-trachelian muscle is found in all mammalia, man alone excepted.
+It is, however, sometimes found in the human being; but it then
+constitutes an anomaly.
+
+In the dog, pig, and ox, it arises from the inferior part of the spine
+of the scapula, in the region of the acromion, and terminates on the
+lateral portion of the atlas.
+
+In the cat it is attached besides to the base of the occipital bone. It
+is visible in the space limited by the trapezius and the
+mastoido-humeral, the direction of which it crosses obliquely.
+
+In the horse it appears to be blended in clearly defined fashion with
+the mastoido-humeral. Attached below, like this latter, to the anterior
+border of the humerus, it covers the scapulo-humeral angle; and is
+attached by its upper portion to the transverse processes of the first
+four cervical vertebræ.
+
+We remember that the transverse processes are often, from their relation
+with the trachea, known as the tracheal processes. Hence the word
+'trachelian,' which forms part of the name of the muscle with which we
+are now dealing.
+
+By its contraction it helps to draw the anterior limb forwards.
+
+When this muscle, as an abnormality, exists in man, it arises from
+the clavicle or the acromion process, traverses the supraclavicular
+fossa, and is inserted into the transverse processes of the atlas or
+axis, or of both these vertebræ, or of the cervical vertebræ below
+these latter. It is then known by the names of the _elevator of the
+clavicle_ or _elevator of the scapula_, and, finally, as the
+_cleido-omo-transversalis_ (Testut).[23]
+
+  [23] L. Testut, 'Les anomalies musculaires chez l'homme expliquées par
+       l'anatomie comparée,' Paris, 1884, p. 97. A. F. Le Double,
+       'Traité des variations du système musculaire de l'homme et de
+       leur signification au point de vue de l'anthropologie
+       zoologique,' Paris, 1897, t. i., p. 235.
+
+=The Levator Anguli Scapulæ= (Fig. 68, 15; Fig. 70, 23).--As we have
+pointed out (p. 136), the levator anguli scapulæ, because of its
+connections with the great serratus, is sometimes described with it. But
+inasmuch as in human anatomy these two muscles are considered
+separately, and that, in the superficial layer of muscles, they are seen
+in different regions--the great serratus in the thoracic, and the
+levator anguli scapulæ in the cervical--we prefer to study them
+separately.
+
+We remember that in man this muscle arises from the transverse processes
+of the upper cervical vertebræ and is inserted into the superior portion
+of the spinal border of the scapula, into the portion of this border
+which is situated above the spine; it also contributes to the formation
+of the floor of the supraclavicular region.
+
+When it contracts, it draws the superior portion of the scapula forwards
+and upwards, and causes a see-saw movement, for at the same time the
+inferior angle of the scapula is directed backwards. Taking its fixed
+point at the shoulder, it directly extends the neck if the muscle of one
+side acts at the same time as that of the opposite; but if only one
+muscle contracts it inclines the neck to the corresponding side.
+
+It is to be noticed that during movements a little more active than the
+ordinary the levator anguli scapulæ, as moreover the other muscles of
+the neck do, becomes very distinct. We have, indeed, often remarked
+that, apart from these movements, each time the support of one of the
+fore-limbs is brought into requisition a brusque contraction of the
+muscles of this region accompanies it.
+
+This contraction gives the impression that, as on the one hand, each
+support determines a momentary arrest of progression, a jolt, and on the
+other hand, the head continues to be projected in the forward direction,
+the latter should be retained. But it cannot be so except by an effort
+in the opposite direction--that is to say, by the brusque contraction
+which we have just pointed out.
+
+Analogous contractions also take place in a man while running at the
+beginning of each contact of the lower limbs with the ground.
+
+We may add, apropos of this latter, that displacements of the head,
+sometimes in very pronounced fashion, take place during simple walking,
+and that every time one of the lower limbs is carried forwards the head
+is projected in the same direction. These displacements, which we also
+find take place in the horse in pacing, especially in the region of the
+neck and head, seem then to have the effect of aiding the progression of
+the body forwards.
+
+They occur especially in animals when drawing a heavy load, and in
+individuals whose walking movements are executed with difficulty.
+
+It is necessary to repeat that, in these cases, the individual appears
+to assist the movement of his body by the impetus which the projection
+of his head forward determines, in order to add--and it is for this that
+we have referred to the subject--that during the intervals between each
+projection the head is carried backwards by a muscular contraction
+similar to that above discussed.
+
+=The Splenius= (Fig. 68, 14; Fig. 70, 22).--In man, this muscle is
+attached in the median line to the inferior half or two-thirds of the
+posterior cervical ligament, to the spinous processes of the seventh
+cervical, and four or five upper dorsal vertebræ; it passes obliquely
+upwards and outwards, becomes visible in the supraclavicular region,
+passes under the sterno-cleido-mastoid, and proceeds to duplicate the
+cranial insertions of this latter; and, further, the most external
+fasciculi of this muscle are inserted into the transverse processes of
+the atlas and the axis.
+
+These separate superior attachments, and the division of the muscle
+which results, have caused the splenius to be regarded as formed of two
+portions: splenius of the head, and splenius of the neck.
+
+In the horse, this muscle, which is of voluminous dimensions, arises
+from the superior cervical ligament, and the spinous processes of the
+first four or five dorsal vertebræ; thence it proceeds to be inserted
+into the mastoid crest, and the transverse processes of the atlas and
+three or four vertebræ following.
+
+The region occupied superficially by the splenius is remarkable for the
+prominence which this muscle, with the deeply-seated complexus, which is
+equally bulky, determines at this level; it is situated above that
+region of the neck, in which are seen in part the fasciculi of the
+levator anguli scapulæ. It terminates above and in front in the ridge,
+which is sometimes very pronounced, which the transverse processes of
+the atlas make on each side of this part of the neck.
+
+In the dog and the cat, the superior and anterior region of the neck is
+thick and of rounded form, on account of the development which the
+splenius presents in those animals; but it is covered by the
+mastoido-humeral.
+
+This latter relation is also found in the ox, but the splenius in this
+case is but slightly developed.
+
+When the splenius contracts it extends the head and neck, while
+inclining them to its own side.
+
+If the splenius of one side contracts at the same time as that of the
+opposite, the extension takes place in a direct manner--that is to say,
+without any modifying lateral movement.
+
+
+Infrahyoid Muscles
+
+Having studied the lateral surfaces of the neck, we must now examine the
+anterior part of this region. Here, between the two sterno-mastoid
+muscles, we find a space broader above than below, in which are situated
+the larynx and the trachea, to the general arrangement of which is due
+the cylindrical form which this region presents. This space corresponds
+to that which in the neck of man is limited laterally by the
+sterno-cleido-mastoid muscles, below by the fourchette of the sternum,
+and above by the hyoid bone. In animals, as in man, it is called the
+infrahyoid region.
+
+The hyoid bone in quadrupeds is situated between the two rami or
+branches of the lower jaw. Owing to this disposition, the region above
+this bone, instead of having its surface projecting a little beyond the
+inferior border of the maxillary bone, is depressed. This is especially
+so in the horse. It is there that we find in this animal the region
+known as the _trough_ (_auge_); the larynx corresponds to that part
+known as the _gullet_.
+
+The muscles which occupy the infrahyoid region are: the sterno-thyroid,
+the sterno-hyoid, and the omo-hyoid. There is also a thyro-hyoid, but
+because of its deep situation and its slight importance it offers no
+interest from our point of view.
+
+=Sterno-thyroid and the Sterno-hyoid Muscles.=--These two muscles, long,
+narrow, and flat, arise from the anterior extremity of the sternum;
+then, covering the anterior surface of the trachea, they proceed to
+terminate, the one on the thyroid cartilage, and the other on the hyoid
+bone. The sterno-hyoid is superficial; it covers the sterno-thyroid,
+which, however, projects a little on its outer side.
+
+=Omo-hyoid.=--This muscle does not exist in the dog or cat. It arises,
+in the horse, from the cervical border of the scapula, where it blends
+with the aponeurosis that envelops the subscapularis muscle, but in the
+pig and the ox it arises from the deep surface of the mastoido-humeral
+muscle. It is directed obliquely upwards and inwards, becoming
+superficial at the internal border of the sterno-mastoid, and is
+inserted into the hyoid bone.
+
+The region in which are united the portion of the neck which we have
+just studied and the neighbouring part of the thorax--that is, the
+breast--has certainly, in our opinion, a form less expressive than the
+corresponding region in man.
+
+In the latter, indeed, the fourchette of the sternum, with the
+hollow which it determines, the heads of the clavicles, and the
+sterno-cleido-mastoid muscles, by the elevations which they produce, and
+the trachea, by the situation which it occupies in the inferior part,
+constitute a whole in which are admirably indicated, not only the forms
+of the organs which constitute this region, but also the relations which
+these organs have one with another; and, to a certain extent, their
+respective functions.
+
+In making an exception in the case of the ox, in which a fold of skin,
+the _dewlap_, which passes from the neck to the breast, constitutes an
+element of form which possesses some expressive value; in the horse and
+in the dog, which possess no sternal fourchette and no heads of
+clavicles, the bones and the muscles are found nearly on the same plane.
+This produces a uniformity which is evidently inferior, from an
+æsthetic point of view, to the modelling of the corresponding region of
+the human body. Such, at least, is our impression.
+
+
+Suprahyoid Muscles
+
+As their name indicates, these muscles are found above the hyoid bone;
+amongst those which should arrest our attention for a moment are the
+mylo-hyoid and the digastric.
+
+=Mylo-hyoid.=--This muscle, forming a sort of fleshy sling which
+contributes in great measure to form the floor of the mouth, is situated
+between the lateral halves of the inferior maxillary bone. Arising on
+each side from the internal oblique line of the mandible, its fibres are
+directed towards the median line, to be inserted posteriorly into the
+hyoid bone, and, between this bone and the anterior part of the
+mandible, into a median raphe which unites these latter.
+
+=Digastric.=--This muscle arises from the styloid process of the
+occipital bone and from the jugular process; it thence passes downwards
+and forwards, and terminates variously, in different species. In the ox
+and the horse it terminates in its anterior portion on the internal
+surface of the inferior maxillary bone, close to the chin. But in the
+horse a bundle of fibres is detached from the upper portion of the
+muscle, to be inserted into the recurved portion of the jaw. It is to
+this fasciculus that Bourgelat has given the name of '_stylo-maxillary
+muscle_.'
+
+In the pig, dog, and cat, the digastric differs more from the
+corresponding muscle in man; it is not, as in the latter, formed of two
+parts. The anterior portion only exists. This consists of a thick
+muscular mass, which is inserted into the middle of the internal surface
+of the lower jaw.
+
+In the dog and cat it is clearly recognisable in the superficial layer
+of muscles by the long and thick prominence which it produces below the
+masseter, against the inferior border of the mandible (see pp. 235 and
+237, the two figures showing the myology of the head of the dog).
+
+By its contraction, it draws the lower jaw downwards and backwards.
+
+=Panniculus of the Neck.=--This very thin muscle, which cannot be
+recognised on the exterior, calls for little notice.
+
+We shall merely point out that it duplicates the skin of the cervical
+region; but as the latter is only slightly adherent to it, the
+panniculus of this region seems rather destined to maintain in position
+the muscles which it covers than to displace the cutaneous covering.
+
+We recall the fact that in man, on the contrary, the muscle is very
+evident at the instant of its contraction, and, for this reason, it
+presents a very great interest with regard to external modelling, and it
+plays an important part in the expression of the physiognomy.
+
+
+MUSCLES OF THE ANTERIOR LIMBS
+
+
+Muscles of the Shoulder
+
+=Deltoid= (Fig. 68, 16, 17; Fig. 69, 18; Fig. 70, 24).--This is the
+first muscle we study in connection with the shoulder in human anatomy.
+Indeed, its wholly superficial position, and especially the manner in
+which it is separated from the surrounding muscles, its volume, and its
+characteristic modelling, give it such an importance that, from the
+didactic point of view, there is every indication for commencing with
+this muscle in studying the region to which it belongs. If, in regard to
+quadrupeds, we also commence with it, it is merely in deference to the
+spirit of method, and for the sake of symmetry; for it is far from
+presenting, in the latter, characters so distinctive and so clearly
+defined.
+
+It is necessary to remark, at the outset, that in quadrupeds, on account
+of the absence or slight development of the clavicle, the clavicular
+portion of this muscle is, as we have shown, united to bundles of the
+same kind belonging to the sterno-cleido-mastoid and trapezius to form
+the mastoido-humeral (see p. 151). There exists, therefore, in an
+independent form, the scapular portion only.
+
+It is this latter which, by itself alone, forms the deltoid of
+quadrupeds, a muscle known, in veterinary anatomy, as _the long abductor
+of the arm_.
+
+In the dog and the cat it consists of two parts, one of which arises
+from the spine of the scapula; the other from the acromion process.
+Thence it passes to the crest of the humerus, which limits the
+musculo-spiral groove anteriorly, to be attached at a point which is
+found, as in other quadrupeds, to be the homologue of the human deltoid
+impression, or deltoid [V], of the human humerus.
+
+In the ox, in which the acromion process, which is very rudimentary,
+does not attain the level of the glenoid cavity, the acromion portion is
+but slightly marked off from that which takes its origin from the spine
+of the scapula.
+
+Still, in the horse, which is completely deprived of an acromion
+process, the deltoid muscle is correspondingly divided into two parts,
+separated from one another by superficial interstices, but of which the
+arrangement differs from that of the portions above indicated; one part,
+the posterior, arises above from the superior part of the posterior
+border, and the postero-superior angle of the scapula (exactly as if, in
+man, certain fasciculi of the deltoid took their origin from the
+axillary border and inferior angle of the scapula); the other, anterior,
+arises from the tuberosity of the spine of the same bone. The two parts,
+united inferiorly, proceed to be inserted into the deltoid impression or
+infratrochiterian crest of the humerus.
+
+It is necessary to add that the deltoid is inserted into the humerus,
+above the insertion of the mastoido-humeral.
+
+This muscle flexes and abducts the humerus, and also rotates it
+outwards.
+
+With regard to the other muscles of the human shoulder, subscapularis,
+supraspinatus, infraspinatus, teres minor and teres major, they are also
+present in quadrupeds, but in a form more elongated, as the scapula has
+its dimensions more extended from below upwards--that is, from the
+glenoid cavity towards the superior or spinal border.
+
+=Subscapularis.=--This muscle occupies the subscapular fossa, from which
+it takes its origin, leaving free the superior part where the surface is
+found, to which are attached the serratus magnus and the levator anguli
+scapulæ. It passes towards the arm, to be inserted into the small
+tuberosity of the humerus. It is an adductor of the arm.
+
+The subscapularis does not offer any interest from the point of view of
+external form, for it is completely covered by the scapula.
+
+We speak of it, however, because we mention it in human anatomy, and
+that it affords us here a new opportunity of bringing into prominence
+the differences which exist in connection with the mobility of the
+shoulder.
+
+We remember that in man, when the arm is abducted, and then raised a
+little above the horizontal, the scapula see-saws, is separated, to a
+certain extent, from the thoracic cage inferiorly and externally, and
+that, on the superficial layer of muscles, we are then able to see in
+the bottom of the armpit, at the level of the deep portion of the
+posterior wall of the latter, a small part of the subscapularis muscle.
+
+In the animals with which we are here occupied it is not the same; for
+they are incapable of performing with their fore-limbs a movement
+analogous to that to which we have just referred, the humerus in their
+case being retained in contact with the trunk by the muscular masses
+which surround it.
+
+=Supraspinatus= (Fig. 68, 19; Fig. 70, 25; Fig. 72, 7).--This muscle, as
+its name indicates, occupies the supraspinous fossa--that is to say,
+that which, by reason of the direction of the scapula in quadrupeds, is
+situated in front of rather than above the spine. It arises from this
+fossa; and, further, from the external surface of the cartilage which
+prolongs the scapula upwards in solipeds and ruminants. It projects more
+or less beyond the supraspinous fossa in front.
+
+After passing downwards towards the humerus, it is inserted into the
+summit of the great tuberosity or trochiter--that is to say, to a part
+of this osseous prominence which represents the anterior facet of the
+great tuberosity of the human humerus, into which, as we know, the
+corresponding muscle is inserted.
+
+In solipeds and ruminants it is inserted, by a second fasciculus, into
+the small tuberosity.
+
+In the pig and the horse its anterior border is in relation with the
+terminal portion of the sterno-prescapular anterior portion of the small
+or deep pectoral.
+
+The supraspinatus, which in man is completely covered by the trapezius,
+is partly visible in the superficial layer of the cat, dog, pig, and
+horse, in the lower part of the space limited by the mastoido-humeral
+and the trapezius. It is crossed by the scapulo-trachelian.
+
+It is, in the ox, completely covered by these muscles, but its form,
+notwithstanding this, is easily discerned by the prominence which it
+produces. When it contracts, the supraspinatus muscle carries the
+humerus into the position of extension.
+
+=Infraspinatus= (Fig. 68, 20; Fig. 72, 8).--This muscle, which occupies
+the infraspinous fossa, which, in quadrupeds, is situated behind the
+spine of the scapula, arises from the whole extent of this fossa, and in
+solipeds and ruminants encroaches on the cartilage of prolongation. Its
+fibres are directed downwards and forwards, to be inserted into the
+great tuberosity of the humerus--the trochiter--below the insertion of
+the supraspinatus.
+
+It is completely covered (ox and horse), or in part only (cat and dog),
+by the portion of the deltoid which arises from the spine of the
+scapula; nevertheless, its presence is revealed by the prominence which
+it produces.
+
+It is an abductor and external rotator of the humerus.
+
+In connection with this muscle, which, as we have just pointed out, is
+less seen in the superficial muscular layer than the supraspinatus, we
+will draw attention to the fact that this arrangement is exactly the
+reverse of that which is found in the human shoulder. In this latter it
+is the supraspinatus which is not visible; while, on the contrary, the
+infraspinatus is uncovered in a considerable part of its extent. We
+further notice that it is accompanied by the teres minor, and that the
+teres major, situated inferiorly, forms with these two muscles a fleshy
+mass which, below, ends on the superior border of the great dorsal
+muscle.
+
+In quadrupeds, in which the infraspinatus is so slightly visible, the
+teres major and minor are not found at all in the superficial muscular
+layer.
+
+Accordingly, we will say but few words about them.
+
+[Illustration: FIG. 72.--MYOLOGY OF THE HORSE--SHOULDER AND ARM: LEFT
+SIDE, EXTERNAL SURFACE.
+
+1, Cartilage of prolongation of the scapula; 2, tuberosity of the spine
+of the scapula; 3, superior extremity of the humerus; 4, inferior
+extremity of the humerus; 5, radius; 6, ulna; 7, supraspinatus muscle;
+8, infraspinatus; 9, teres minor; 10, biceps; 11, tendon of the biceps
+passing over the anterior surface of the superior extremity of the
+humerus; 12, brachialis anticus; 13, triceps, long head; 14, external
+head of the triceps divided; 15, external head of the triceps reflected,
+in order to expose the anconeus; 16, region normally occupied by the
+external head of the triceps; 17, anconeus.]
+
+=Teres Minor= (Fig. 72, 9).--This muscle, also called in veterinary
+anatomy _the short abductor of the arm_, arises from the posterior
+border of the scapula (the external border in man), and is inserted
+below the great tuberosity of the humerus, between the attachments of
+the infraspinatus and deltoid.
+
+It is covered by the deltoid and the infraspinatus.
+
+=Teres Major.=--This muscle is known to veterinarians as _the abductor
+of the arm_; it arises from the postero-superior angle of the scapula
+(the inferior angle of the human scapula), from which it passes to be
+inserted into the internal surface of the humerus.
+
+It is covered by the latissimus dorsi and the posterior muscular mass of
+the arm.
+
+In brief, for the better understanding of the relations of the teres
+major and minor muscles in quadrupeds, we may fancy the corresponding
+muscles in man modified in the following manner: The infraspinatus,
+thicker, covering the teres minor; latissimus dorsi, more extended in
+its superior part, covering a large proportion of the teres major. As to
+the relations of the teres minor with the deltoid, they exist in man,
+seeing, in this case, the same muscle is, in its external portion,
+covered by this latter. With regard to the relations of the teres major
+with the posterior muscular mass of the arm, they also exist in man,
+since the external surface of this muscle is covered by the triceps.
+
+These modifications are sufficient to render the small and large teres
+muscles completely invisible in the superficial layer.
+
+The muscles of the shoulder which we have just been studying fulfil,
+with regard to the articulation which they surround, the function of
+active ligaments. This rôle is made necessary by the laxity of the
+scapulo-humeral capsule--a laxity which renders it incapable by itself
+of maintaining the bones in contact at this joint.
+
+The same condition exists in man.
+
+=Panniculus Muscle of the Shoulder.=--This thin muscle covers, as its
+name implies, the region of the shoulder, and is the continuation
+forward of the panniculus muscle of the trunk.
+
+It arises, by its superior part, from the region of the withers and from
+the superior cervical ligament; thence its fibres descend directly
+towards the elbow, to terminate at the level of the region of the
+forearm.
+
+The muscle is not found in the pig or in the carnivora.
+
+
+Muscles of the Arm
+
+We should remember, at the outset, that in man the muscles of the arm
+are divided into two groups: one anterior, which contains the biceps,
+brachialis anticus, and the coraco-brachialis; the other, posterior,
+which is constituted by a single muscle, the triceps.
+
+In animals, we find them in the same number and arranged in analogous
+fashion--that is to say, in two groups--with respect to the bone of the
+arm. But then we find that they have undergone a transformation with
+regard to their length, and it is the change of general aspect which
+results from this modification that we proceed to examine.
+
+We know that in quadrupeds, and especially in the domestic animals, the
+humerus is relatively short in proportion to the forearm. We have
+already seen, in dealing with the bones, that whilst in the human
+species the humerus is longer than the forearm, in the dog and cat these
+two segments of the fore-limb are of equal length, and that the humerus
+of the horse is, on the contrary, much shorter. Now, let us suppose the
+human humerus to be shorter than it is in reality; the anterior muscles
+undergoing, very naturally, the same reduction, will be uncovered only
+slightly by those above--the deltoid and the great pectoral--or will
+remain completely hidden by them. Thus would be found realized the
+disposition which we meet with in quadrupeds of the muscles of this
+region.
+
+With regard to the posterior muscular mass of the arm, it does not
+undergo the same change. The muscle which constitutes it--the triceps
+cubiti--occupies, on the contrary, a greater area. Let us suppose,
+further--for it is the best method of comprehending the homologies which
+now occupy our attention--the humerus of man to be shortened as before,
+and directed downwards and backwards (as in quadrupeds), this bone would
+form an acute angle with the axillary border of the scapula. Let us
+suppose also that the long portion of the triceps, instead of arising
+solely from the superior part of this axillary border, is attached to
+the whole length of the latter, and that the triceps fills the whole
+interior of the angle formed by the arm and the shoulder. We then shall
+have an idea of what the triceps is in quadrupeds. It is necessary to
+add that the general resemblance would be still more complete if the arm
+were firmly supported by the side of the thorax, because in quadrupeds
+it occupies an analogous position, determined by the arrangement of the
+muscles which, proceeding from the trunk and neck, are attached to it.
+
+
+Anterior Region
+
+=Biceps Cubiti= (Fig. 68, 21; Fig. 72, 10, 11).--This muscle, also
+called _the long flexor of the forearm_, does not merit the name except
+by its analogy with the corresponding muscle in man. Indeed, in the
+domestic animals it is not divided into two parts; it is represented by
+a single fasciculus, long and fusiform, situated on the front of the
+humerus, and directed obliquely downwards and backwards, as the latter,
+on its part, is also inclined.
+
+It arises above from a tubercle at the base of the coracoid process,
+which surmounts the glenoid cavity of the scapula. Its tendon, which is
+highly developed in the solipeds, occupies the bicipital groove. We
+remember that in these latter the groove in question is divided into two
+channels by a median prominence.
+
+The tendon in which the muscle ends is inserted into a tuberosity,
+situated on the internal surface of the superior extremity of the
+radius--the bicipital tuberosity. In the pig, the cat, and the dog,
+there is detached from the tendon to which we have just referred a
+fasciculus of the same nature, which, after having wound round the
+radius, is inserted into the internal surface of the ulna, towards the
+base of the olecranon process. From the inferior part of the muscle
+arises a fibrous band, comparable to the aponeurotic expansion of the
+human biceps; but, instead of passing downwards and inwards, as does the
+latter, it terminates on the muscular mass which constitutes the
+antero-external part of the forearm.
+
+The biceps is not seen in the superficial layer, except in the dog and
+cat (in which the humerus is, in fact, proportionately long); and even
+in them only to the slightest extent. It is covered partly in these
+latter, and completely in other animals, by the great pectoral and the
+inferior portion of the mastoido-humeral--that is to say, that part of
+the latter which represents the whole of the clavicular fibres of the
+human deltoid.
+
+The biceps is a flexor of the forearm on the arm. It also contributes to
+the movement of extension of the humerus.
+
+=Brachialis Anticus= (Fig. 68, 22; Fig. 69, 19; Fig. 70, 27; Fig. 72,
+12).--In veterinary anatomy further designated as _the short flexor of
+the forearm_, this muscle, which is thick, occupies the musculo-spiral
+groove, and arises from it, reaching upwards to just below the head of
+the humerus. But it does not, as in man, extend to the internal surface
+of the bone.
+
+Situated on the outside of the biceps, it is directed towards the
+forearm, and terminates by a flattened tendon, which, dividing into two
+slips, passes below the bicipital tuberosity, on the internal surface of
+the radius, into which one of these slips is inserted, while the other
+proceeds to terminate on the ulna.
+
+The inferior half of this muscle is visible on the superficial layer, in
+the space limited posteriorly by the triceps brachialis, and below by
+the muscles of the forearm, which correspond to the external muscles of
+the human forearm, and in front by the great pectoral and the
+mastoido-humeral. It is in the upper part of the interspace which
+separates these latter from the brachialis anticus that the deltoid
+insinuates itself to proceed to its insertion into the humerus.
+
+These relations precisely recall those which we meet with when we
+examine the external surface of the human arm, with this difference,
+however--that in the latter the anterior brachialis anticus is
+extensively related, in front, to the biceps. However, in animals it is
+not absolutely the same, since, as we have shown above, the biceps is
+covered, more or less completely, by the mastoido-humeral and the great
+pectoral.
+
+The brachialis anticus flexes the forearm on the arm.
+
+=Coraco-brachialis.=--In man this muscle, which occupies the superior
+half, or third, of the internal surface of the humerus, is visible only
+when the arm is abducted, and then especially when it approaches the
+vertical position; indeed, it is only in this attitude that the region
+which it occupies is accessible to view.
+
+But an analogous attitude not being possible in domestic animals, in
+which the arm is fixed along the corresponding parts of the trunk, the
+result is that the coraco-brachialis is always covered, and that,
+consequently, it presents nothing of interest from our point of view. We
+speak of it, then, merely in order to complete the series of the muscles
+of the anterior surface of the arm, among which we rank it, in spite of
+the fact that in veterinary anatomy it is described as a muscle of the
+shoulder.
+
+It arises above from the coracoid process, and thence passes downwards
+towards the internal surface of the humerus into which it is inserted,
+more or less high up, according to the species. The coraco-brachialis is
+an adductor of the arm.
+
+
+Posterior Region
+
+=Triceps Cubiti= (Fig. 68, 23, 24; Fig. 69, 20, 21; Fig. 70, 28, 29;
+Fig. 72, 13, 14, 15, 16).--This muscle, which is voluminous in the
+quadrupeds with which we are here concerned, fits more or less
+completely the angular space between the scapula and the humerus. Its
+bulk forms a thick prominence, which surmounts the elbow and the
+forearm.
+
+We should say, with regard to this mass, that if the deltoid does not
+constitute in quadrupeds a prominence sufficient to remind one of that
+which this muscle produces in man, the triceps, in producing an
+analogous elevation, seems to replace in the general form of the body
+the relief which the deltoid is incapable of producing.
+
+The triceps is divided into three portions, which, as in man, have the
+names middle, or long head; external and internal heads. But that which
+renders the nomenclature a little complicated is that veterinary
+anatomists have given other names to these three parts: that of _great
+extensor of the forearm_ (caput magnum) to the long head; _the short
+extensor of the forearm_ (caput parvum) to the external head; and of
+_medium extensor of the forearm_ (caput medium) to the internal.[24]
+
+  [24] Other names given by certain authors to the parts of this muscle
+       which we have just enumerated still further complicate this
+       nomenclature.
+
+The long head is further designated by them under the names of the
+_long_ or _great anconeus_; the _external head_ under those of _external
+anconeus_, or _lateral_ or _short anconeus_; whilst the internal head
+becomes the _internal anconeus_, or _median_.
+
+It is more especially the long portion and the external head which,
+being visible on the external surface of the arm, contribute to the
+external form.
+
+The long portion, which is triangular in shape and of considerable
+development, arises in the cat and the dog from the inferior half or
+two-thirds of the posterior border of the scapula (axillary border);
+from the whole extent of that border as far as the superior posterior
+angle in the pig, the ox, and the horse; it then passes downwards
+towards the articulation of the elbow, to terminate in a tendon which is
+inserted into the olecranon process. The portion of this muscle which is
+next the scapula is covered by the deltoid.
+
+The external head, situated below the long portion, is directed
+obliquely downwards and backwards. It arises from the curved crest
+which, from the deltoid impression of the humerus, is directed upward to
+meet the articular head of the same bone. This crest limiting the
+musculo-spiral groove superiorly, and the brachialis anticus arising
+from the whole extent of this groove, the result is that at this level
+the external head is in relation with the brachialis anticus. From this
+origin it is directed towards the elbow, to be inserted into the
+olecranon, either directly or by the medium of the tendon of the long
+portion. The part of this muscle which arises from the humerus is
+covered by the deltoid.
+
+As for the internal head (Fig. 76, 4), which, in the superficial layer,
+is only visible in its inferior part, on the internal aspect of the arm
+in those animals in which the elbow is free of the lateral wall of the
+thorax (the dog and the cat, for example), it arises from the internal
+surface of the humerus, and thence proceeds to be inserted into the
+olecranon.
+
+The triceps extends the forearm on the arm.
+
+A fourth muscle exists, which veterinary anatomists include in the study
+of the three portions of the triceps which we have just been discussing,
+in giving it the name of _small extensor of the forearm_. But, as this
+muscle is no other than the anconeus, and as, in human anatomy, we
+describe the latter, according to custom, in connection with the
+forearm, it is when on the subject of the latter that we will concern
+ourselves with it. This grouping of muscles cannot fail to give greater
+clearness to the description of the muscles of these regions.
+
+=The Supplemental or Accessory Muscle of the Latissimus Dorsi= (Fig. 76,
+2; Fig. 77, 1).--Because of the relations, to which we have already
+referred (see p. 142), of this muscle with the triceps cubiti, its
+description very naturally follows that of the latter.
+
+Indeed, this supplementary muscle of the great dorsal is further
+designated in zoological anatomy under the name of _long extensor of the
+forearm_; and this name indicates that its study may be united to that
+of the triceps.
+
+Situated on the internal surface of the arm, it arises from the external
+aspect of the tendon of the latissimus dorsi; it is very highly
+developed in the horse, in which it also arises from the posterior
+border (axillary) of the scapula; then, covering in part the internal
+head of the triceps and also the long portion, on the superior border of
+which it is folded, it proceeds to be inserted into the olecranon
+process and the anti-brachial aponeurosis.
+
+It extends the forearm on the arm. Further, it makes tense the
+aponeurosis into which it is inserted; this explains the name of _tensor
+of the fascia of the forearm_, which is sometimes given to it.
+
+It seems to us interesting to add that, abnormally, we sometimes find in
+man an analogue of this muscle. It is given off from the latissimus
+dorsi, near the insertion of the latter into the humerus; it accompanies
+the long head of the triceps and becomes fused with it. Sometimes it is
+inserted into the olecranon process, at other times into the
+antibrachial aponeurosis or the epitrochlea. It is on account of its
+insertion into the last-mentioned, in some cases, that it is also
+designated by the name of _dorso-epitrochlear_ muscle.[25]
+
+  [25] L. Testut, 'Anomalies musculaires chez l'homme expliquées par
+       l'anatomie comparée,' Paris, 1884, p. 118. A. F. Le Double,
+       'Traité des variations du système musculaire de l'homme et de
+       leur signification au point de vue de l'anthropologie
+       zoologique,' Paris, 1897, t. i., p. 203. Édouard Cuyer,
+       'Anomalies musculaires' (_Bulletins de la Société
+       Anthropologique_, Paris, 1893).
+
+
+Muscles of the Forearm
+
+Before commencing the special examination of each of the muscles of this
+region, it is absolutely indispensable to consider their general
+arrangement, and to determine very clearly how we should study them. We
+are too well convinced of the importance of this preliminary examination
+to dismiss it without entering rather fully into it. Indeed, the region
+on the myological study of which we are now entering is, unquestionably,
+one of the most complicated with which we have to deal. We know besides,
+in regard to the study of the forearm in man, how much a definite method
+is necessary in order that the arrangement of the muscles of this region
+be fixed in the memory, and that we are unable to obtain this result
+otherwise than by grouping the twenty muscles which constitute it in
+clearly defined regions.
+
+We also know that these muscles are first studied with the forearm in
+the position of supination, and that it is only when they are well known
+after having considered them in this position that we are able to
+analyze and comprehend their forms when it is in pronation.
+
+Now, as we have pointed out in the section on osteology (see p. 34), the
+forearm in quadrupeds is always in the position of pronation. Should we,
+then, in order to maintain the symmetry with human anatomy, first study
+the forearm in the position of supination? Evidently not. Besides the
+fact that this would in some cases be impossible since--as in the horse,
+for example--the radius and ulna are fused together, we should not gain
+any advantage; this position being never completely realizable even in
+those quadrupeds which have the radius relatively movable--as, for
+example, in the cat.
+
+Accordingly, it is pronation which here, in connection with animals,
+becomes the standard attitude from the point of view of description.
+This is why, supposing that the reader knows well the muscles of the
+human forearm in the position of supination, we should recall what is
+the general arrangement occupied by these muscles when it is in
+pronation.
+
+The fore-limb, being viewed on its anterior surface, presents above the
+anterior aspect of the region of the elbow; but below, it is the
+posterior surface of the wrist which is seen. Consequently, in the
+superior part, we see the external and anterior muscles limiting the
+hollow in front of the elbow; interiorly are found the posterior
+muscles.
+
+The long supinator, passing obliquely downwards and inwards, divides, in
+fact, the forearm into two parts: one supero-internal, the other
+infero-external. In the first we see, but to an extent less and less
+considerable, the pronator teres, the flexor carpi radialis, the
+palmaris longus, and the flexor ulnaris; as to the flexors of the
+digits, on account of the rotation of the radius, they are only visible
+on the opposite surface--that is to say, on the surface of the wrist,
+which is now posterior. In the second part we see the two radial
+extensors, the common extensor of the fingers, the proper extensor of
+the little finger, and the ulnar extensor which, inferiorly, remains
+behind, by reason of the position of the ulna being unchanged, whilst
+the anconeus is wholly posterior, since the direction of the elbow is
+not modified. We also find, in this region, the long abductor of the
+thumb, the short extensor of the thumb, the long extensor of the thumb,
+and the special extensor of the index-finger, in the region where these
+deep muscles become superficial.
+
+So that, to summarize, the external and posterior muscles occupy the
+anterior and external regions of the forearm, whilst the anterior
+muscles occupy rather the internal and posterior. It is in regarding
+them after this manner--that is to say, arranged in these two
+regions--that we proceed to study these muscles in quadrupeds.
+
+
+Anterior and External Region
+
+=Supinator Longus.=--We know that this muscle, which is especially a
+flexor of the forearm on the arm, plays, notwithstanding the name which
+has been given it, a part of but little importance in the movement of
+supination.
+
+It acts slightly, however, as a supinator, for, being very oblique
+downwards and inwards at the time of pronation, it is able, while
+tending to resume its vertical direction, to carry the radius outwards;
+it places, in fact, the forearm in a position midway between pronation
+and supination.
+
+We have just recalled these details, in order that it may be more easy
+to understand why it does not exist in animals in which the radius and
+ulna are fused together (horse, ox); and why, on the other hand, we find
+traces of it in the cat and the dog, in which the radius--to a slight
+extent, it is true--is able to rotate on the ulna. This displacement
+being a little more considerable in the felide, the long supinator is a
+little further developed than it is in the canine species; but,
+notwithstanding, it is only rudimentary.
+
+The long supinator arises, above, from the external border of the
+humerus; thence, in the form of a very narrow fleshy band, it passes
+obliquely downwards and inwards, to be inserted into the inferior part
+of the internal surface of the radius.
+
+It assists in turning the radius outwards and placing it in front of the
+ulna, the movement of supination being capable of being but little
+further extended.
+
+=First and Second External Radial Muscles=: _Extensor carpi radialis
+longior and brevior_ (Fig. 73, 8; Fig. 74, 8, 9; Fig. 75, 8, 9).--Fused
+together, these muscles form by their union what veterinary anatomists
+call _the anterior extensor of the metacarpus_. But we should add that
+these two muscles are united so much the more intimately as we examine
+them in passing successively from the cat to the dog, pig, ox, and
+horse. Thus, in the cat they are often distinct; in the dog, they unite
+only at the level of the middle third of the radius, and interiorly they
+have two tendons; in the pig, the ox, and the horse they are completely
+united, and there exists but a single tendon.
+
+The _anterior extensor of the metacarpus_, which is situated behind the
+long supinator when the latter exists, occupies the external aspect of
+the forearm; its well-defined form absolutely recalls the prominence on
+the superior part of the external margin of the human forearm.
+
+It arises superiorly from the portion of the external border of the
+humerus which is situated above the epicondyle and behind the
+musculo-spiral groove. Its fleshy mass appears in the angular space
+bounded by the brachialis anticus and the triceps. The superior portion
+is covered by the external head of the triceps; yet, in the dog, the
+superior portion of its humeral attachment is the only part so covered.
+This muscle is directed forward and downwards; it is also inclined a
+little inwards in such manner as to proceed to occupy the anterior
+aspect of the forearm.
+
+Its fleshy belly is narrowed below, and, towards the inferior part of
+the forearm, is continued by a tendinous portion which is situated on
+the anterior surface of the carpus, after having traversed the median
+groove of the inferior extremity of the radius.
+
+In the cat and the dog, in which the union of the two radial extensors
+is incomplete, the two tendons are inserted into the front of the base
+of the second and third metacarpal bones; consequently, as in man, into
+the metacarpals of the index and middle fingers.
+
+In the ox, the tendon, which is single, is inserted into the internal
+and anterior half of the superior extremity of the principal metacarpal.
+
+In the pig, this tendon is attached to the base of the large internal
+metacarpal.
+
+In the horse, the corresponding tendon is attached to a tubercle which
+is situated on the anterior surface of the base of the principal
+metacarpal, a little internal to the median plane of the latter.
+
+[Illustration: FIG. 73.--MYOLOGY OF THE DOG: LEFT ANTERIOR LIMB,
+EXTERNAL ASPECT.
+
+1, Mastoido-humeralis; 2, biceps; 3, brachialis anticus; 4, triceps,
+long portion; 5, triceps, external head; 6, olecranon process; 7,
+epicondyle; 8, radialis muscles (anterior extensor of the metacarpus);
+9, extensor communis digitorum (anterior extensor of the phalanges); 10,
+extensor minimi digiti (lateral extensor of the phalanges, or common
+extensor of the three external digits); 11, posterior ulnar (external
+flexor of the metacarpus); 12, pisiform bone; 13, anconeus; 14, extensor
+ossis metacarpi pollicis and extensor primi internodii pollicis (oblique
+extensor of the metacarpus); 15, radius; 16, anterior ulnar (oblique
+flexor of the metacarpus); 17, external border of the hypothenar
+eminence (abductor of the little finger).]
+
+In order to properly understand and remember the respective positions
+occupied by these inferior insertions, it must be remembered that the
+human forearm being in the position of pronation, the tendons of the
+radials are attached to the bases of the metacarpals nearest to the
+thumb--that is to say, those occupying an internal position as regards
+the fourth and fifth metacarpals.
+
+As its name indicates, this muscle extends the metacarpus. Consequently
+it is, in the horse, an extensor of the canon-bone.
+
+It is also an adductor of the hand in those animals (cat, dog) in which
+the radio-carpal articulation, analogous in form to the corresponding
+articulation in man, permits lateral movements of the hand on the
+forearm. The union of the fleshy bodies of the two radials is sometimes
+found in the human species.
+
+=Supinator Brevis.=--As in the case of the long supinator, the short
+supinator is found only in animals in which the radius can be rotated to
+a greater or less extent around the ulna; therefore this muscle is not
+found in the pig, the ox, or the horse; but it forms part of the forearm
+of the cat and the dog.
+
+Deeply situated at the region of the elbow, the short supinator has
+little interest for us. All that we will say of it is that it goes from
+the external part of the inferior extremity of the humerus to the
+superior part of the radius; and that it is, in carnivora, the essential
+agent in the production of the movement of supination.
+
+=Extensor Communis Digitorum= (Fig. 73, 9, 10, 11; Fig. 74, 10, 11,
+12).--Also named in veterinary anatomy the _anterior extensor of the
+phalanges_, this muscle is situated external to and behind the anterior
+extensor of the metacarpus already described.
+
+In the human being, the common extensor of the fingers springs, in its
+superior part, from the bottom of a depression, situated on the outer
+side of and behind the elbow, and limited in front by the muscular
+prominence which the long supinator and the first radial extensor form
+at that level. At the bottom of this hollow or fossette is found the
+epicondyle, which gives origin, amongst other muscles, to the common
+extensor of the fingers. It is necessary to add that it is most
+prominently visible during supination, and that it tends to be effaced
+during pronation.
+
+[Illustration: FIG. 74.--MYOLOGY OF THE OX: LEFT ANTERIOR LIMB, EXTERNAL
+ASPECT.
+
+1, Mastoido-humeralis; 2, pectoralis major; 3, deltoid; 4, brachialis
+anticus; 5, triceps; 6, triceps, external head; 7, olecranon; 8, radial
+extensors (anterior extensor of the metacarpus); 9, insertion of the
+tendon of the anterior extensor of the metacarpus to the tubercle of the
+superior extremity of the principal metacarpal; 10, 11, extensor
+communis digitorum (10, proper extensor of the inner digits; 11, common
+extensor of the two digits); 12, tendon of the common extensor of the
+two digits; 13, band of reinforcement from the suspensory ligament of
+the fetlock; 14, external tuberosity of the superior extremity of the
+radius; 15, extensor minimi digiti (proper extensor of the external
+digit); 16, tendon of the proper extensor of the external digit; 17,
+posterior ulnar (external flexor of the metacarpus); 18, pisiform; 19,
+extensor ossis metacarpi pollicis and extensor primi internodii pollicis
+(oblique extensor of the metacarpus); 20, ulnar portion of the deep
+flexor of the toes; 21, tendon of the superficial flexor of the toes
+(superficial flexor of the phalanges); 22, tendon of the deep flexor of
+the toes (deep flexor of the phalanges); 23, suspensory ligament of the
+fetlock.]
+
+An analogous arrangement is met with in animals. But the muscular
+prominence is formed by the united radial extensors, and the fossette,
+because of the permanent pronation of the forearm, is scarcely
+recognisable. Likewise, with regard to the dog, we may say that it does
+not exist, on account of the prominence which the epicondyle forms in
+that animal (Fig. 73, 7).
+
+In connection with this prominence of the epicondyle, it is interesting
+to add that this detail recalls the relief which the same process
+produces on the external aspect of the human elbow when the forearm is
+flexed on the arm. We know that, in this case, the epicondyle is
+exposed, because the muscles which mask it in supination (long supinator
+and long radial extensor) are displaced and set it free during flexion.
+But, in the dog, as in other quadrupeds besides, the forearm is, in the
+normal state, flexed on the arm; the latter being oblique downwards and
+backwards, and the former being vertical. Further, the epicondyle is
+well developed.
+
+The muscle with which we are now occupied, long and vertical in
+direction, arises from the inferior part of the external border of the
+humerus (there it is covered by the anterior extensor of the metacarpus,
+from which it is freed a little lower down) and from the external and
+superior tuberosity of the radius. In the carnivora, it arises from the
+epicondyle. Its fleshy body is fusiform in shape, becomes tendinous in
+the lower half of the forearm, and then divides into a number of slips,
+varying in number according to the species; this division is correlated
+to that of the hand--that is to say, with the number of the digits.
+Before reaching this latter, the common extensor of the digits passes
+through the most external groove on the anterior surface of the inferior
+extremity of the radius.
+
+[Illustration: FIG. 75.--MYOLOGY OF THE HORSE: LEFT ANTERIOR LIMB,
+EXTERNAL ASPECT.
+
+1, Mastoido-humeral; 2, pectoralis major; 3, deltoid; 4, brachialis
+anticus; 5, triceps, long head; 6, triceps, external head; 7, olecranon;
+8, radial extensors (anterior extensor of the metacarpus); 9, insertion
+of the tendon of the anterior extensor of the metacarpus into the
+tubercle of the superior extremity of the principal metacarpal; 10,
+extensor communis digitorum (anterior extensor of the phalanges); 11,
+tendon of the anterior extensor of the phalanges; 12, reinforcing band
+arising from the suspensory ligament of the fetlock; 13, external
+tuberosity of the superior extremity of the radius; 14, extensor minimi
+digiti (lateral extensor of the phalanges); 15, tendon of the lateral
+extensor of the phalanges; 16, fibrous band which this latter receives
+from the tendon of the anterior extensor of the phalanges; 17, fibrous
+band which the same tendon receives from the carpal region; 18,
+posterior ulnar (external flexor of the metacarpus); 19, pisiform; 20,
+extensor ossis metacarpi pollicis and extensor primi internodii pollicis
+(oblique flexor of the metacarpus); 21, ulnar portion of the deep flexor
+of the digits; 22, flexor digitorum profundus; 23, 23, tendon of the
+flexor digitorum sublimis (superficial flexor of the phalanges); 24, 24,
+tendon of the flexor digitorum profundus (deep flexor of the phalanges);
+25, sesamoid prominence; 26, suspensory ligament of the fetlock; 27,
+external rudimentary metacarpal.]
+
+In the cat and the dog, the four tendons which result from the division
+of the principal tendon go to the four last digits, and each of them is
+inserted, as in the human species, to the second and third phalanges.
+
+In the pig, the anterior extensor of the phalanges is rather complicated
+in its arrangement. Its fleshy body is divided into four bundles
+terminated by tendons, which in turn divide and join certain digits;
+whence the special names given to each of these fasciculi, commencing
+with the most internal, of: _proper extensor of the great inner toe_;
+_common extensor of the two inner toes_; _common extensor of the two
+outer toes_; and _proper extensor of the great outer toe_.
+
+In the ox, the same muscle is divided into two bundles: the internal
+proceeds to the internal toe, the external is common to the two toes.
+
+In the horse, the tendon of the anterior extensor of the phalanges is
+divided into two parts of unequal bulk. The smaller of these tendinous
+slips, which is the more external, unites at the level of the superior
+part of the metacarpus with the tendon of the muscle which we are about
+to study in the following paragraph (Fig. 75, 16). The larger, after
+having reached the anterior surface of the digit, is attached to the
+anterior aspect of the first and second phalanges, and then forms a
+terminal expansion which is inserted into the pyramidal eminence of the
+third.
+
+At the level of the first phalanx this tendon receives on each of its
+lateral aspects a strengthening band, which proceeds from the terminal
+extremity of _the suspensory ligament of the fetlock_,[26] and crosses
+obliquely downwards and forwards over the surface of the first phalanx
+to join the extensor tendon (Fig. 75, 12).
+
+  [26] See p. 200 for a description of this ligament.
+
+A similar arrangement is found in the ox.
+
+This band is noticeable under the skin which covers the lateral aspects
+of the ham.
+
+As the name indicates, this muscle extends the phalanges, one upon the
+other. It also contributes to the extension of the hand, as a whole, on
+the forearm.
+
+=Extensor Minimi Digiti= (Fig. 73, 10; Fig. 74, 15, 16; Fig. 75, 14,
+15).--This muscle, _the lateral extensor of the phalanges_ of veterinary
+anatomy, situated on the external surface of the forearm, behind the
+common extensor of the digits, arises, as a rule, from the epicondyle
+(dog, cat), or from the external surface of the superior extremity of
+the radius (horse). The tendon succeeding to the fleshy body appears
+towards the lower third of the forearm, and at the level of the wrist
+lies in a groove analogous to that which in man is hollowed out for the
+passage of the corresponding tendon at the level of the inferior
+radio-ulnar articulation. This groove corresponds to the same
+articulation in animals in which the ulna is well developed, such as the
+dog and the cat; but it belongs to the radius when the inferior
+extremity of the ulna does not exist--for example, in the horse. Indeed,
+in this animal the groove in question is found on the external surface
+of the carpal extremity of the radius.
+
+In the dog, the tendon is divided into three parts, which, crossing
+obliquely the tendons of the common extensor of the digits, pass to the
+three external digits, to be inserted by blending with the corresponding
+tendons of the latter into the third phalanges of those digits.
+
+Thus is explained the name of _common extensor of the three external
+digits_ which is sometimes given to this muscle.
+
+In the cat, there is a fourth tendon, which passes to the index-finger,
+so that the name _common extensor of the four external digits_ is in
+this case legitimate, and the lateral extensor of the phalanges is also
+a common extensor, as is the anterior extensor of the phalanges, or
+common extensor of the digits.
+
+In the pig, the tendon, which is single, is inserted into the external
+digit, for which reason it has received the name of the _proper extensor
+of the small external digit_. This muscle is, then, really the homologue
+of that which exists in the human species.
+
+In the ox, it is called the _proper extensor of the external digit_; it
+is as thick as the common extensor.
+
+Finally, in the horse, the muscle is little developed. Its fleshy body,
+thin and flattened from before backwards, becomes distinctly visible
+only below the middle of the forearm. Above, it is enclosed in a limited
+space, bounded in front by the common extensor of the digits, and
+behind by the posterior ulnar; there these two muscles approach each
+other so closely that from the point of view of external form they seem
+to be nearly in contact.
+
+The tendon, after receiving the small fasciculus from the common
+extensor (Fig. 75, 16), as well as a fibrous band emanating from the
+external surface of the carpus (Fig. 75, 17), is situated at the
+external side of the tendon of the anterior extensor of the phalanges,
+and is inserted into the anterior surface of the superior extremity of
+the first phalanx.
+
+This muscle extends the digit or digits into which it is inserted. It
+also assists in the movement of extension of the hand as a whole.
+
+=Posterior Ulnar= (_Extensor carpi ulnaris_) (Fig. 73, 11; Fig. 74, 17;
+Fig. 75, 18).--Designated by veterinary anatomists as the _external
+flexor of the metacarpus_,[27] or _external cubital_, this muscle is
+situated in the posterior region of the external surface of the forearm,
+behind the lateral extensor of the phalanges.
+
+  [27] Certain authors give it the name of _ulnar extensor of the
+       wrist_. It is true that in the human being this is its action;
+       but in quadrupeds, owing to its insertion into the pisiform, it
+       draws the hand into the position of flexion.
+
+It arises from the epicondyle; its fleshy body, thick but flattened, is
+directed vertically towards the carpus, and its tendon is inserted into
+the external part of the superior extremity of the metacarpus, after
+having given off a fibrous band, which takes its attachment on the
+pisiform.
+
+It is inserted, in the cat and the dog, into the superior extremity of
+the fifth metacarpal; in the pig to the external metacarpal; in the ox
+to the external side of the canon-bone; in the horse to the superior
+extremity of the external rudimentary metacarpal.
+
+This muscle flexes the hand on the forearm, and in animals in which the
+radio-carpal articulation permits, by its formation, it inclines the
+hand slightly outwards--that is, abducts it.
+
+=Anconeus= (Fig. 72, 17; Fig. 73, 13).--We have already stated (p. 174)
+that the anconeus is included with the triceps brachialis in zoological
+anatomy, and that veterinary anatomists give it the name of _small
+extensor of the forearm_.[28]
+
+  [28] It is also called by some authors, the _small anconeus_.
+
+In the dog it recalls, as to position, the human anconeus, but with this
+difference--that, in the latter, the anconeus, triangular in outline,
+has one of its angles turned outwards (the epicondyloid attachment) and
+one of its sides turned towards the olecranon. Here it is entirely the
+opposite. The anconeus, similarly triangular, is broader externally. At
+this level it takes its origin from the external border of the humerus,
+the epicondyle, and the external lateral ligament of the articulation of
+the elbow; thence its fibres converge towards the external surface of
+the olecranon, to be there inserted.
+
+It is in relation, anteriorly and inferiorly, with the posterior ulnar
+muscle. It is covered superiorly by the external head of the triceps. In
+the cat the disposition of the anconeus is analogous. But in the other
+quadrupeds with which we are here concerned it is completely covered by
+the external head of the triceps. It really participates in the
+formation of the triceps; and seeing that it takes origin from the
+posterior surface of the humerus at the margin of the olecranon fossa
+(Fig. 72), and proceeds thence towards the olecranon to be inserted, we
+can understand why veterinary anatomists have connected its study with
+that of the posterior muscular mass of the arm.
+
+This muscle is an extensor of the forearm on the arm.
+
+We proceed now to inquire what the deep muscles of the posterior region
+of the human forearm become in quadrupeds: the long abductor of the
+thumb, the short extensor of the thumb, the long extensor of the thumb,
+the proper extensor of the index. We know that in every instance these
+muscles, which are deeply seated at their origin, become superficial
+afterwards.
+
+In quadrupeds, on account of the position in which the forearm is
+placed--viz., pronation--the corresponding muscles occupy the anterior
+aspect of this region.
+
+=Long Abductor of the Thumb= (_Extensor ossis metacarpi pollicis_) =and
+Short Extensor of the Thumb= (_Extensor primi internodii pollicis_)
+(Fig. 73, 14; Fig. 74, 19; Fig. 75, 20).--United one to the other in
+man, blended in quadrupeds, they form in the latter the muscles to which
+veterinary anatomists give the name of _oblique extensor of the
+metacarpus_.
+
+This muscle arises from the median portion of the skeleton of the
+forearm. There it is covered by the common extensor of the digits and
+that of the small digit (anterior extensor and lateral extensor of the
+phalanges). Then, at the internal border of the first of these muscles,
+it becomes superficial, passes downwards and inwards, crosses
+superficially the anterior extensor of the metacarpus, reaches the
+inferior extremity of the radius, and becomes lodged in the most
+internal of the grooves situated on the anterior surface of this
+extremity, passes on the internal side of the carpus, and is inserted
+into the superior extremity of the most internal metacarpal--that is, to
+the first metacarpal, or metacarpal of the thumb--in the dog and cat; to
+the internal rudimentary metacarpal in the horse.
+
+It is an extensor of the metacarpal into which it is inserted; but as,
+if we recall the extreme examples given above, in the dog the first
+metacarpal is not very mobile, and in the horse the internal rudimentary
+metacarpal is absolutely fixed to the bone which it accompanies, it is
+more exact to add that this muscle is principally an extensor of the
+metacarpus as a whole.
+
+And yet, in the cat and the dog, it is also able to adduct the first
+metacarpal bone. It must be understood that this movement would be
+abduction, if the hand could be placed in the position of complete
+supination, as in the human species.
+
+=Long Extensor of the Thumb= (_Extensor secundi internodii pollicis_)
+=and Proper Extensor of the Index= (_Extensor indicis_).--These two
+muscles are blended together by their fleshy bodies, so that the single
+name of _proper extensor of the thumb and index_ is preferable. This
+muscle is but of slight importance from our point of view, for it is
+extremely atrophied, and so much the more as the number of the digits is
+lessened.
+
+It arises, as the preceding, from the skeleton of the forearm, and there
+it is deeply placed. Below, towards the carpus, its tendinous part
+becomes superficial, to end in the following manner:
+
+In the carnivora, the tendon divides into two very slender parts, which
+are inserted into the thumb and the index. In the pig, the tendon is
+blended with that of the common extensor of the internal digits.
+Finally, in the ox and the horse, it is sometimes regarded as being
+blended with the common or anterior extensor of the phalanges. But to us
+it appears more rational to say that it does not exist, which, moreover,
+is explained by the digital simplification of the hand.
+
+
+Internal and Posterior Region
+
+=Pronator Teres= (Fig. 76, 8).--This muscle, as may easily be
+understood, undergoes, as do the supinators, a degree of degeneration in
+proportion to the loss of mobility of the radius on the ulna. In animals
+in which the bones of the forearm are not fused it exists; in those, on
+the other hand, in which this segment has become simply a supporting
+column, it is not developed--at least, in a normal manner.
+
+It is, consequently, found best marked in the dog and the cat.
+
+Forming, as in man, the internal limit of the hollow of the elbow, the
+pronator teres has a disposition analogous to that which characterizes
+the corresponding muscle in the human species. It arises from the
+epitrochlea (internal condyle), proceeds downwards and outwards, and is
+inserted into the middle portion of the body of the radius.
+
+It is into the hollow in front of the elbow, which this muscle
+contributes to limit, that the biceps and the brachialis anticus dip.
+
+In the pig and the ox it is atrophied.
+
+In the horse it does not exist. We may, however, sometimes find it, but
+in an abnormal form. We were able to demonstrate its presence in the
+form of a fleshy tongue situated on the internal side of the elbow
+(Fig. 78) in a horse which we dissected many years ago in the laboratory
+of the School of Fine Arts. Moreover--and the fact seemed to us an
+interesting one--the forearm to which the muscle belonged had an ulna of
+relatively considerable development (Figs. 79 and 80).[29]
+
+  [29] Édouard Cuyer, 'Abnormal Length of the Ulna and Presence of a
+       Pronator Teres Muscle in a Horse' (_Bulletin de la Société
+       d'Anthropologie_, Paris, 1887).
+
+This muscle is a pronator.
+
+=Flexor Carpi Radialis= (Fig. 76, 10; Fig. 77, 7).--Called by veterinary
+anatomists _the internal flexor of the metacarpus_, this muscle, which
+is found on the internal aspect of the forearm, is situated behind the
+pronator teres when this muscle exists, whilst in the animals which are
+deprived of the latter the flexor carpi radialis has in front of it the
+internal border of the radius, which separates it from the anterior
+extensor of the metacarpus.
+
+It is necessary to add that the flexor carpi radialis is similarly
+separated from the anterior extensor of the metacarpus by the internal
+border of the radius in animals in which the pronator teres exists, but
+then only in that part of the forearm which is situated below this
+latter.
+
+The flexor carpi radialis arises from the epitrochlea. Its fleshy body,
+fusiform in shape, descends vertically, and terminates in a tendon on
+the posterior surface of the bases of the second and third metacarpals
+in the dog and the cat, on the metacarpal of the large internal digit in
+the pig, on the internal side of the metacarpus in the ox, and on the
+superior extremity of the internal rudimentary metacarpal in the horse.
+
+We see clearly, in this latter, a superficial vein which, in the shape
+of a strong cord, passes along the anterior border of the flexor carpi
+radialis; it is the subcutaneous median or internal vein, which, forming
+the continuation of the internal metacarpal vein, joins the venous
+system of the arm, after having crossed obliquely the corresponding part
+of the radius.
+
+=Palmaris Longus.=--This muscle, which exists distinctly in some
+animals, but whose absence is far from being rare in the human species,
+is not developed as a distinct muscle in any of the domestic quadrupeds.
+
+[Illustration: FIG. 76.--MYOLOGY OF THE DOG: LEFT ANTERIOR LIMB,
+INTERNAL ASPECT.
+
+1, Biceps; 2, long extensor of the forearm (supplementary or accessory
+muscle of the great dorsal); 3, triceps, long head; 4, triceps, internal
+head; 5, olecranon; 6, epitrochlea (internal condyle); 7, radial
+extensors (anterior extensor of the metacarpus); 8, pronator teres; 9,
+radius; 10, flexor carpi radialis (internal flexor of the metacarpus);
+11, anterior ulnar (oblique flexor of the metacarpus); 12, superficial
+flexor of the digits; 13, deep flexor of the digits; 14, flexor longus
+pollicis (radial fasciculus of the deep flexor of the digits); 15,
+pisiform bone.]
+
+And yet some authors announce its presence in the dog, and describe it
+as becoming detached, in the form of a cylindrical bundle, from the
+anterior surface of the fleshy mass of the deep flexor of the digits
+(see p. 196) to proceed then by a tendon which divides into two parts,
+to terminate in the palm of the hand, where it blends with the tendons
+of the superficial flexor, which are destined for the third and fourth
+digits.
+
+These authors give to this muscle the name of _palmaris longus_, and
+attribute to it the action of flexing the hand.
+
+=Anterior Ulnar= (_Flexor carpi ulnaris_) (Fig. 73, 16; Fig. 76, 11;
+Fig. 77, 8).--Called by veterinary anatomists the _oblique flexor of the
+metacarpus_, or _internal ulnar_, this muscle occupies the internal part
+of the posterior aspect of the forearm in the ox and the horse, while in
+the dog it occupies rather the external part.
+
+This difference arises from the fact that in this latter, as in man, the
+anterior ulnar is separated from the flexor carpi radialis by an
+interval in which we see, on the internal aspect of the forearm, just at
+the level of the elbow, the flexors of the digits. This interval is so
+much the wider as there is no palmaris muscle to subdivide its extent
+(Fig. 81). In the horse, the interval in question does not exist. In
+this animal, indeed, the anterior ulnar is in contact with the radial
+flexor, so that this muscle can occupy only a region belonging rather to
+the internal surface of the forearm (Fig. 82).
+
+In the dog the anterior ulnar is in contact with the posterior ulnar.
+This relation recalls that which is found in man, where the two muscles
+are merely separated by the crest of the ulna (Fig. 81). But in the
+horse, in which the anterior ulnar has, so to speak, slid towards the
+internal aspect, this muscle is separated above from the posterior
+ulnar, and it is in the interval separating these two muscles that we
+are able to perceive, but this time at the back of the forearm, the
+muscular mass of the flexors of the digits (Fig. 82).
+
+[Illustration: FIG. 77.--MYOLOGY OF THE HORSE: ANTERIOR LIMB, LEFT SIDE,
+INTERNAL ASPECT.
+
+1, Long extensor of the forearm (supplementary or accessory muscle of
+the latissimus dorsi); 2, radialis muscles (anterior extensor of the
+metacarpus); 3, tendons of extensor ossis metacarpi pollicis extensor
+primi internodii pollicis united (oblique extensor of the metacarpus);
+4, tendon of extensor communis digitorum (anterior extensor of the
+phalanges); 5, strengthening band from the suspensory ligament of the
+fetlock; 6, internal surface of the radius; 7, flexor carpi radialis
+(internal flexor of the metacarpus); 8, anterior ulnar (oblique flexor
+of the metacarpus); 9, pisiform bone; 10, 10, tendon of the superficial
+flexor of the digits (superficial flexor of the phalanges); 11, 11,
+tendon of the deep flexor of the digits (deep flexor of the phalanges);
+12, sesamoid prominence; 13, suspensory ligament of the fetlock; 14,
+internal rudimentary metacarpal.]
+
+The anterior ulnar arises above from the epitrochlea and the olecranon;
+thence it is directed towards the carpus, to be inserted into the
+pisiform bone. It proceeds therefore from the inner side of the elbow to
+the outer side of the upper part of the hand; it consequently crosses
+the posterior surface of the forearm obliquely. This is why, as we have
+pointed out above, it receives the name of the oblique flexor of the
+metacarpus.
+
+It is not unprofitable to recall in this connection that there is an
+internal flexor of the metacarpus, which is the flexor carpi radialis;
+and an external flexor of the metacarpus, which is the posterior ulnar
+(in human anatomy, extensor carpi ulnaris). It is between these two
+muscles that we find the oblique flexor--the anterior ulnar which we
+have just been studying.
+
+This muscle flexes the hand on the forearm.
+
+=Superficial Flexor of the Digits= (_Flexor digitorum sublimis_) (Fig.
+76, 12; Fig. 77, 10, 10).--This muscle arises from the epitrochlea;
+thence it passes towards the hand, becomes tendinous, passes in a groove
+on the posterior aspect of the carpus, and terminates on the palmar
+surface of the phalanges in furnishing a number of tendons proportioned
+to the digital division of the hand. Whatever the number, to which we
+will again refer, each tendon is attached to the second phalanx, after
+bifurcating at the level of the first, so as to form a sort of ring,
+destined to give passage to the corresponding tendon of the deep flexor.
+This ring and this passage have gained for the muscle the name of
+_perforated flexor_.
+
+In the dog and the cat the principal tendon is divided into four parts,
+which go to the four last digits.
+
+In the ox it is divided into two parts only; as, moreover, in the pig,
+whose superficial flexor is destined for the two large digits only, the
+lateral digits receiving no part of it.
+
+Finally, in the horse the tendon is single.
+
+We have previously pointed out that in the carnivora this muscle is
+visible on the internal and posterior aspects of the forearm, in the
+interval which is limited in front by the flexor carpi radialis and
+behind and outside by the anterior ulnar.
+
+Certain details are still to be added to the description of this
+muscle. We will enter on an analysis of them after we have given some
+indications relative to the following muscle:
+
+=Deep Flexor of the Digits= (_Flexor digitorum profundus_) (Fig. 75, 21,
+22; Fig. 76, 12; Fig. 77, 11, 11).--This muscle is covered by the
+superficial flexor. It arises from the epitrochlea, from the radius, and
+from the ulna, either from the olecranon process--as in the ox, pig, and
+horse--or from almost the whole extent of the shaft of the same bone, as
+in the cat and dog.
+
+[Illustration: FIG. 78.--LEFT ANTERIOR LIMB OF THE HORSE: INTERNAL
+ASPECT.
+
+1, Internal flexor of the metacarpus or great palmar; 2, inferior part
+of the biceps; 3, inferior part of the brachialis anticus; 4, internal
+lateral ligament of the elbow; 5, pronato teres muscle.]
+
+The radial fasciculus represents in the domestic quadrupeds the long
+proper flexor muscle of the thumb in man. For this reason we shall
+describe the muscle afresh in the following paragraph:
+
+The fleshy bundles of which we have just spoken terminate in a tendon
+which afterwards divides into slips, the number of which is in
+proportion to the digital division of the hand. These slips then pass
+through the slit or _buttonhole_ in the tendon of the superficial
+flexor, and proceed to terminate on the third phalanx; hence the name of
+_perforating_, which is also given to the deep flexor of the digits.
+
+In the dog and the cat the tendon is divided into five portions, each of
+which proceeds to one of the digits. The internal tendon, which is
+destined for the thumb, terminates on the second phalanx of this digit.
+
+In the pig the tendon divides into four tendons destined for the four
+digits.
+
+In the ox there are but two tendons.
+
+In the horse the tendon is single.
+
+As their names indicate, these muscles, both superficial and deep, flex
+the digits. In addition to this, they flex the hand on the forearm.
+
+We mentioned above that certain details relative to the superficial
+flexor must be analyzed in a special way. We now add that this should
+also be done with regard to the deep flexor. The point in question is
+the arrangement which the tendons of these muscles present at the level
+of the palmar region of the hand.
+
+It is easy, in the case of the dog or the cat, to picture to one's self
+this arrangement, especially if we recollect that which exists in the
+human species. The tendons of the flexors are placed on a kind of
+muscular bed formed by the union of the muscles of the region, but,
+moreover, from the point of view of external form, these tendons are not
+of very great importance.
+
+But in the ox and the horse it is quite otherwise. From the
+simplification of the skeleton of the hand, and the reduction of the
+number of movements which the bones that form it are able to execute,
+there naturally results a diminution of its muscular apparatus. Apart
+from the existence of muscular vestiges of but little importance, we can
+say that, in reality, the hand does not possess any muscles. On its
+palmar aspect are found only the tendons of the flexors of the digits,
+and as these tendons are large, and the hand long, they give origin to
+external forms which it is necessary to examine.
+
+[Illustration: FIG. 79.--LEFT ANTERIOR LIMB OF THE HORSE: EXTERNAL
+ASPECT.
+
+1, Ulna of abnormal length.]
+
+[Illustration: FIG. 80.--LEFT ANTERIOR LIMB OF THE HORSE: EXTERNAL
+ASPECT.
+
+1, Normal ulna.]
+
+In the horse, which we take as a type, the tendons of the flexors, after
+being retained in position at the carpus by a fibrous band, the _carpal
+sheath_, which recalls the anterior annular ligament of the human
+carpus, and having passed this region, descend vertically, remaining
+separated from the posterior surface of the metacarpus, so that the skin
+sinks slightly on the lateral parts in front of the thick cord which
+these tendons form. This cord is known by the name of _tendon_.
+
+The flexors then reach the fetlock, and occupy the groove formed by the
+peculiar arrangement of the two large sesamoid bones. They are retained
+in position at this level by a fibrous structure, which forms the
+metacarpo-phalangeal sheath. They then reach the phalanges, being
+directed obliquely downwards and forwards, as, moreover, the latter are
+also inclined. Then the tendon of the superficial flexor divides into
+two slips, which are inserted into the second phalanx, between which
+slips passes the tendon of the deep flexor, which in its turn goes to be
+inserted, in the form of an expansion, into the semilunar crest, by
+which the inferior surface of the third phalanx is divided into two
+parts.[30]
+
+  [30] See, as regards this crest, in the paragraph relative to the hoof
+       of the solipeds, the figures which represent the third phalanx,
+       viewed on its inferior surface (Figs. 101 and 102, p. 258).
+
+The part which these tendons play is of great importance in the large
+quadrupeds.
+
+These tendons, in fact, in addition to the action determined by the
+contraction of the fleshy fibres to which they succeed, maintain the
+angle formed by the canon-bone and the phalangeal portion of the hand,
+and prevent its effacement under the weight of the body during the time
+of standing. Their strong development, and the position they occupy,
+make this understood, without it being necessary to insist on it
+further.
+
+We mentioned above that the 'tendon' descends vertically from the carpus
+towards the fetlocks. This is as it should be. But, in some horses, it
+is oblique downwards and backwards, so that the canon, instead of being
+of equal depth from before backwards in its whole length, is a little
+narrower in its upper part.
+
+This results from the fact that the tendons of the flexors, too firmly
+bound by the carpal sheath, gradually separate as they pass from the
+metacarpus, going to join the fetlock; hence the obliquity pointed out
+above. This abnormality producing a deleterious result, in the sense
+that the tendinous apparatus acts with less strength as an organ of
+support, it constitutes a defect of conformation which is expressed by
+saying that the tendon has 'failed.'
+
+=Long Proper Flexor of the Thumb= (_Flexor longus pollicis_) (Fig. 76,
+14).--As we have already pointed out, this muscle is represented in
+quadrupeds by the radial bundle of the deep flexor of the digits, so
+that the two muscles are in reality blended the one to the other. This
+union is sometimes found, but only as an abnormality, in the human
+species. We have met some examples of this in the course of our
+dissections.
+
+=Pronator Quadratus.=--This muscle conforms to the general law which we
+have already pointed out in connection with those which have for their
+action the rotation of the radius around the ulna. We remember, indeed,
+that when the bones of the forearm are fused with one another, the
+muscles which are destined to produce a mobility which has then become
+impossible disappear at the same blow.
+
+[Illustration: FIG. 81.--DIAGRAM OF THE POSTERIOR PART OF A TRANSVERSE
+SECTION PASSING THROUGH THE MIDDLE OF THE LEFT FORE-LIMB OF THE DOG:
+SURFACE OF THE INFERIOR SEGMENT OF THE SECTION.
+
+1, Radius; 2, ulna; 3, posterior ulnar; 4, anterior ulnar; 5, great
+palmar (_flexor carpi radialis_); 6, flexors of the digits.]
+
+[Illustration: FIG. 82.--DIAGRAM OF A HORIZONTAL SECTION OF THE MIDDLE
+OF THE FOREARM OF THE LEFT LEG OF THE HORSE: SURFACE OF THE INFERIOR
+SEGMENT OF THE SECTION.
+
+1, Radius; 2, ulna; 3, posterior ulnar; 4, anterior ulnar; 5, great
+palmar (_flexor carpi radialis_); 6, flexors of the digits.]
+
+For this cause we do not find the square pronator in either the ox or
+the horse, but can demonstrate its presence in the dog and the cat.
+
+It is very deeply situated. This is why, and also on account of the plan
+which we have traced for ourselves, we will simply say that it is
+situated on the postero-internal aspect of the skeleton of the forearm,
+and that it extends from the ulna to the radius.
+
+It seems to us, however, sufficiently interesting to add that, instead
+of occupying, as in the human species, the inferior fourth of the two
+bones, it extends, particularly in the dog, over their whole length,
+with the exception of their superior and inferior extremities.
+
+
+Muscles of the Hand
+
+We will first recall that, in man, the palm of the hand is divided into
+three regions: a median palmar region, which is occupied by the tendons
+of the flexors of the digits, the lumbricales, and, deeply, by the
+interosseous muscles; an external region, or thenar eminence, formed by
+the muscles destined for the movements of the thumb; an internal region,
+or hypothenar eminence, which contains the muscles proper to the small
+digit and the palmar cutaneous muscle.
+
+These muscles are found, more or less developed, in the dog and the cat.
+
+In the ox and the horse we meet with no vestige of the muscles of the
+thenar or hypothenar eminences. Nevertheless, in these animals we find
+the muscles which belong to the central region of the palm. We refer to
+the lumbricales and the interosseous.
+
+Although this fact has no relation to the object of our study, it
+appears to us interesting to announce that there are traces of the
+lumbricales found in the solipeds. These muscles are represented by two
+fleshy bundles, situated one on each side of the tendon of the deep
+flexor, above the ring of the tendon of the superficial flexor. These
+small muscles are continued as slender tendons, which become lost in the
+fibrous tissue of the _spur_, which is the horny process situated at the
+posterior part of the fetlock, and which is covered by the hairs, more
+or less abundant, which constitute the _wisp_.
+
+As for the interosseous muscles, they are represented by the _suspensory
+ligament of the fetlock_, and by two other small muscles, tendinous
+throughout, which are situated between the principal metacarpal and the
+rudimentary ones.
+
+The suspensory ligament of the fetlock is considered an interosseous
+muscle, on account of the red fleshy striations which it contains, and
+from certain relations which it forms with the tendon of the common
+extensor of the digits or anterior extensor of the phalanges. This
+ligament (Fig. 75, 26; Fig. 77, 13), which plays an important part in
+the standing position as a support of the foot, is a fibrous band
+situated between the tendons of the flexors of the digits and the
+principal metacarpal. It arises above, from the second row of the
+carpals, descends towards the fetlock, where it divides into two
+branches, which are inserted into the large sesamoid bones. At the same
+level, this ligament gives off two fibrous bands which, passing
+downwards and forwards, join the tendon of the anterior extensor of the
+phalanges, blending with it, after having each crossed one of the
+lateral aspects of the pastern. We have already referred to these bands
+(p. 183).
+
+It is with these latter that are blended the long and slender tendons
+which form in a great measure the two other interosseous muscles
+previously described.
+
+A ligament of the same kind is found in the ox (Fig. 74, 23).
+
+
+MUSCLES OF THE POSTERIOR LIMBS
+
+
+Muscles of the Pelvis
+
+The muscles which specially interest us in this region, because of their
+superficial position, are the gluteus maximus and the gluteus medius. As
+for the gluteus minimus, it is deeply situated, and more or less sharply
+marked off from the second of the preceding muscles.
+
+Inasmuch as the gluteus medius is more simple in arrangement than the
+maximus, and will aid us in arranging our ideas in connection with the
+latter, it is with the study of it that we will commence.
+
+=Gluteus Medius= (Fig. 68, 29; Fig. 69, 26; Fig. 70, 35).--This muscle,
+as in man, occupies the external iliac fossa. But this latter being
+directed differently in the digitigrades and the ungulates, as we have
+pointed out in the section on osteology (see pp. 91 and 99), the muscle
+in question has consequently not the same direction in the two groups of
+animals, being turned outwards in the first, and upwards in the second.
+
+It is the thickest of the glutei, and gives to the region which it
+occupies a rounded form.
+
+From the iliac fossa from which it arises the fleshy fibres are directed
+towards the femur, to be inserted into the great trochanter. It is
+covered by an aponeurosis, and in part by the great gluteal. It
+completely covers the small gluteal, which veterinary anatomists
+designate by the name of the _deep gluteal_.
+
+In the carnivora it does not pass in front of the iliac crest, but, in
+the ox, and more particularly in the horse, it is prolonged anteriorly,
+and thus covers, to a certain extent, the muscles of the common mass.
+
+When it contracts, taking its fixed point at the pelvis, the gluteus
+medius extends the thigh, which it is also able to abduct. If, on the
+other hand, its fixed point is on the femur, it acts on the trunk, which
+it raises, producing oscillating movements of the pelvis. It contributes
+in this way to the action of rearing. We also see it distinctly appear
+by the prominence which it produces in the dog, which, according to the
+time-honoured phrase, _fait le beau_.
+
+=Gluteus Maximus= (Fig. 68, 28; Fig. 69, 25; Fig. 70, 33, 34).--The
+great gluteal muscle, further designated in veterinary anatomy the
+_superficial gluteal_, is proportionately less developed in quadrupeds
+than in man. Indeed, in the latter, where it is of very great thickness,
+its volume is due to the important function which it fulfils in
+maintaining the biped attitude.
+
+In quadrupeds it contributes to form the superficial part of the crupper
+and the external surface of the thigh. It is divided into two parts: one
+anterior, the other posterior.
+
+With regard to this latter, it will be necessary to indicate how it has
+been sometimes regarded, and to what portion of the muscular system in
+man it corresponds. But we believe that it is better to see beforehand,
+without any preconceived idea, how these two parts are arranged.
+
+In the dog, the anterior portion of the gluteus maximus arises from the
+sacrum, while some fibres situated further forward arise from the
+surface of the gluteus medius, near the iliac spine, and from the tensor
+of the fascia lata with which these fibres are blended. The posterior
+portion, united to the preceding--that is to say, to those of its fibres
+which arise from the sacrum--takes its origin from the first coccygeal
+vertebra. These two portions are directed towards the femur, to be
+inserted into the great trochanter, and to the external branch of the
+superior bifurcation of the linea aspera.
+
+In the cat, the posterior bundle is less definitely blended with the
+anterior. By a long and slender tendon which, behind, turns around the
+great trochanter, and passes along the surface of the fascia lata, it
+proceeds to join the knee-cap.
+
+In the pig, the posterior portion is much more developed.
+
+In the horse, the anterior portion arises from the internal iliac spine
+(posterior in man), from the external iliac spine (anterior in man),
+and, between these two osseous points, from the aponeurosis, which
+covers the gluteus medius. Between these two origins the muscle is
+deeply grooved, so that the tendency is to divide into two portions,
+each of which is directed towards one of the iliac angles. In this
+groove the gluteus medius is to be seen.
+
+The fleshy bundles converge, and are directed towards the external
+aspect of the femur, to be inserted into the osseous prominence known as
+the third trochanter, after passing beneath the fleshy fibres of the
+posterior portion. The latter, which is more considerable than the
+preceding portion, arises above from the sacral crest, from the
+aponeurosis which envelops the coccygeal muscles, from the sacro-sciatic
+ligament, and from the tuberosity of the ischium. From this origin it
+passes downwards, expands, then, describing a curve with the convexity
+behind, it becomes narrowed, and proceeds to be inserted by a deep
+fasciculus into the third trochanter, to the fascia lata, and, lastly,
+to the knee-cap by the inferior part of its tendon.
+
+Above, its posterior border is covered by the semi-tendinosus;
+interiorly, the same border is in relation with the biceps femoris.
+
+In the ox, the two parts of the great gluteal muscle are blended
+together.
+
+The long and broad fleshy band which they form arises in a manner
+corresponding to that which we have just indicated in connection with
+the horse, except that it has no attachment to the femur. The fascia
+lata adheres strongly to its anterior border for a considerable length.
+The form of the superior border of the great gluteal muscle of this
+animal differs from that of the analogous portion in the horse. This
+difference results from the peculiar aspect which the corresponding
+region of the pelvis presents, and from the fact that, in the ox, as the
+semi-tendinosus does not cover the portion of the great gluteal which
+arises from the tuberosity of the ischium, the attachments of this
+muscle to the sacro-sciatic ligament are uncovered.
+
+Its descending portion, as a whole, has a rectilinear form, and does not
+form a curve such as we indicated in the case of the horse.
+
+The anterior portion of the great gluteal flexes the thigh. As regards
+the posterior portion, it extends the thigh, and abducts it.
+
+The action of this latter portion is particularly interesting as regards
+the horse, because of the great development of the muscular mass which
+this region presents in this animal. If the muscle takes its fixed point
+above, it acts, in the extension of the thigh during walking, by
+projecting the trunk forward during the whole time that the hind-limb to
+which it belongs is in contact with the ground. If, on the contrary, it
+takes its fixed point below, it makes the pelvis describe a see-saw
+movement, upwards and backwards, on the coxo-femoral articulation, and
+so contributes to the action of rearing.
+
+Now that we have a knowledge of the disposition of the great gluteal
+muscle, the moment has come to inquire what is the signification of its
+posterior portion. The action of the anterior part being clearly
+comparable to the human great gluteal, there can be no doubt as regards
+the homology of this portion, so we will not insist on it further.
+
+Of the posterior portion it is wholly different, for it is the homologue
+of a fleshy bundle annexed to the great gluteal of man, but which is not
+developed except as an abnormality.
+
+Indeed, we sometimes find, placed along the inferior border of the great
+gluteal, a fleshy fasciculus, separated from this muscle by a slight
+interspace. This fasciculus, long and narrow, takes origin from the
+summit of the sacrum, or the coccyx, and goes to partake of the femoral
+insertions of the muscle which it accompanies. We further note a muscle
+of the same kind, and presenting the same aspect, which comes from the
+tuberosity of the ischium. Notwithstanding the difference which exists,
+it is this abnormal fasciculus of man which in the quadrupeds here
+studied is considered as constituting the posterior portion of the great
+gluteal.
+
+Bourgelat, considering this posterior portion as belonging to the biceps
+cruris, to which, it is true, it adheres, forms of them a muscle which
+he designates under the name of the _long vastus_. The anterior
+fasciculus of this long vastus is none other than the posterior portion
+of the great gluteal which we have just been studying.
+
+
+Muscles of the Thigh
+
+These muscles are divided into three regions: posterior, anterior, and
+internal.
+
+In a corresponding manner to that which we described in connection with
+the arm, the thigh is applied to the side of the trunk, and is free,
+more or less, only at the level of the inferior part.
+
+Further, by reason of this shortening of the femur, the great gluteal
+muscle, which is elongated in the ox and the horse, for example,
+occupies in part the region corresponding to that which in man is
+occupied by the muscles of the thigh, which here are reduced in length.
+In other words, they are not superposed, as in the human species, but
+juxtaposed. This is what we will verify further on.
+
+The thigh, as a whole, is flattened from without inwards, its transverse
+diameter being less in extent than its antero-posterior. Its external
+surface is slightly rounded; that is, of course, in quadrupeds with
+sufficiently well-developed muscles. Its internal surface is known as
+the _flat of the thigh_.
+
+
+Muscles of the Posterior Region
+
+It is not unprofitable to recall to mind what muscles form the
+superficial layer of this region in the human being. They are the biceps
+cruris, semi-tendinosus, and semi-membranosus. We now proceed to
+discover their analogues in quadrupeds.
+
+=Biceps Cruris= (Fig. 68, 30; Fig. 69, 27; Fig. 70, 36).--It is this
+which, according to Bourgelat, forms the central and posterior portions
+of the long vastus muscle which we have mentioned above.
+
+We know that the biceps of man is so named from the two portions which
+form its upper part. In domestic quadrupeds, and also in the majority of
+the mammals, this muscle is reduced to a single portion, that which
+comes from the pelvis. It is therefore the portion which arises from the
+femur which does not exist. This condition is sometimes found as an
+abnormality in the human species.
+
+The biceps arises from the tuberosity of the ischium; hence it is
+directed, widening as it goes, towards the leg, where it terminates by
+an aponeurosis which blends with the fascia lata and the aponeurosis of
+the leg, and then proceeds to be attached to the anterior border or
+crest of the tibia. By its inferior portion it limits externally the
+posterior region of the knee--the popliteal space.
+
+A fibrous intersection traverses the biceps in its whole length, with
+the result that the muscle looks as if formed of two portions, one of
+which is situated in front of the other.
+
+In the dog and the cat it also arises from the sacro-sciatic ligament.
+At this level its contour is distinguishable from that which corresponds
+to the gluteal muscles, so that we there find two prominences one above
+the other. The superior is formed by the gluteal muscles; the inferior
+corresponds to the tuberosity of the ischium. The two prominences are
+separated by a depression, from which the biceps emerges. We draw
+attention to this form, the character of which is so expressive of
+energy in the carnivora.
+
+In these animals the biceps is inserted, by its anterior fibres, into
+the articulation of the knee, while in the rest of its extent it covers
+in great measure by its aponeurosis the external aspect of the leg.
+
+In the pig, the biceps is but slightly marked off from the posterior
+part of the great gluteal. In the ox, the division between these two
+muscles is a little more distinct.
+
+In the horse, the sciatic origin of the biceps is covered by the
+semi-tendinosus, so that it only becomes free lower down, to appear in
+the space limited behind by the semi-tendinosus, and in front by the
+posterior part of the gluteus maximus.
+
+When the biceps contracts, taking its fixed point from above, it flexes
+the leg and helps to extend the thigh. If, on the other hand, it takes
+its fixed point from below, it lowers the ischium, makes the pelvis
+undergo a see-saw movement, and acts thus in the movement of rearing. It
+is sometimes called, on account of one of its actions, and the position
+which it occupies, the 'external flexor, or peroneal muscle of the leg.'
+
+=Semi-tendinosus= (Fig. 68, 31; Fig. 70, 37; Fig. 87, 1; Fig. 88, 1;
+Fig. 89, 28).--This muscle forms the contour of the thigh posteriorly,
+so that when the latter is viewed from the side, it is the
+semi-tendinosus above all that forms the outline. But, as we shall soon
+see, it is in this case more distinct above than below, because of the
+deviation which it undergoes in order to occupy by its inferior part the
+internal side of the leg.
+
+In the dog, the cat, and the ox, the semi-tendinosus arises from the
+tuberosity of the ischium only, as in the human species. In the pig, it
+also takes origin higher up from the sacro-sciatic ligament and the
+coccygeal aponeurosis. In the horse, it extends still further, for it is
+also attached to the crest of the sacrum.
+
+The indication of these origins is of importance from the point of view
+of external form, and to convince ourselves of this it is sufficient to
+compare, in the ox and the horse, the region of the pelvis situated
+below the root of the tail. In the ox, whose semi-tendinosus arises from
+the tuberosity of the ischium only, this region is depressed, and the
+cavity which is formed at this level is limited behind by the
+tuberosity, which we know is very thick and prominent above. This causes
+the superior part of the crupper to be less oblique than in the horse.
+This characteristic is more especially marked in the cow, the bull
+having this region of a more rounded form.
+
+In the horse, on account of the semi-tendinosus ascending to the coccyx,
+and even to the sacrum, the depression in question does not exist, and
+the presence of the tuberosity of the ischium is only slightly revealed.
+
+Descending from the origin indicated above, and inclining more and more
+inwards, the semi-tendinosus proceeds to blend with the aponeurosis of
+the leg, to be inserted into the anterior border of the tibia, after
+crossing over the internal surface of the latter. It forms the internal
+boundary of the popliteal space.
+
+When this muscle contracts, taking its fixed point at the pelvis, it
+flexes the leg. If, on the other hand, it takes its fixed point at the
+tibia, it makes the pelvis describe a see-saw movement, and acts
+accordingly in the movement of rearing.
+
+It is sometimes named the 'internal or tibial flexor of the leg,' in
+opposition to the crural biceps, which, as stated above, is then the
+external flexor of the same region.
+
+=Semi-membranosus= (Fig. 68, 32; Fig. 87, 2; Fig. 88, 2).--This muscle,
+situated on the inner side of the semi-tendinosus, can be seen only when
+the thigh is regarded on its posterior aspect.
+
+It is only by reason of the homology of situation with the corresponding
+muscle in man that we give the name under which we are studying it;
+indeed, its structure is different, for it does not present the long,
+broad, aponeurotic tendon which, in its superior part, characterizes
+this muscle in the human species.
+
+It arises above from the inferior surface of the ischium, and from the
+tuberosity of the same bone. In the pig, and especially in the horse, it
+passes further upwards, to arise from the aponeurosis of the coccygeal
+muscles. So that if we compare it with that of the ox, which does not
+extend beyond the ischium, we find that it is associated with the
+semi-tendinosus in determining the difference of aspect to which we have
+already called attention in connection with the region of the pelvis
+situated below the root of the tail.
+
+The semi-membranosus is then directed downwards and forwards, to take
+its place on the internal surface of the thigh, where it is partly
+covered by the gracilis muscle. It is inserted in the following manner:
+
+In the dog and the cat it is divided into two parts, anterior and
+posterior. The first, the more developed, is attached to the internal
+surface of the inferior extremity of the femur; the second to the
+internal tuberosity of the tibia.
+
+The same arrangement occurs in the ox.
+
+In the horse it is inserted into the internal surface of the internal
+condyle of the femur.
+
+The semi-membranosus is an extensor of the thigh when it takes its fixed
+point at the pelvis; it is also an adductor of the lower limb. If it
+takes its fixed point below it assists in the action of rearing.
+
+It is now necessary for us, especially as regards the horse, to add some
+indications relative to the exterior forms of the region constituted by
+the semi-membranosus and semi-tendinosus. These two muscles form, by
+their union, a surface contour, slightly projecting and of elongated
+form, which occupies the posterior border of the thigh, the contour
+corresponding to the region known as the _buttock_, in spite of the
+fact that none of the gluteal muscles take any part in the structure of
+this region. But the appearances, to a certain extent, justify the
+preservation of this name. Indeed, because of the groove which separates
+the gluteal region of one side from that of the opposite side, and from
+the position of the anal orifice in the superior part of this groove, we
+may admit the name which, in hippology, has been given to this part of
+the thigh.
+
+In addition to the reasons just given, and which are justified
+especially by the position occupied by the muscular mass formed by the
+union of the two muscles, there is another which, this time, has a
+relation to a certain detail of form. In the superior part of the
+convexity, which the gluteal region describes in the greater part of its
+extent, there is found a more salient point, greatly accentuated in lean
+animals, due to the presence of the tuberosity of the ischium; it is the
+_point_ or _angle of the buttock_. At this level, and near the median
+line, the semi-membranosus, not aponeurotic, but fleshy, and even
+thicker there than anywhere else, sometimes produces a sharply localized
+prominence. And as this prominence is situated on the outer side of the
+anal orifice, the resemblance to a small 'buttock' is still more marked.
+
+In lean horses a deep groove separates the mass formed by the
+semi-membranosus and semi-tendinosus from that of the other muscles of
+the thigh situated more in front; this groove is known by a name which
+in this case is remarkably expressive--that of the 'line of poverty.'
+
+If we examine the gluteal region as a whole by looking at the thigh from
+the side, we plainly see the graceful curve produced by the general
+convexity above indicated. We return to this point, in order to add
+that, in its lower part, this curve alters its character; that is to
+say, it is replaced by a slight concavity. This, which is designated
+under the name of _the fold of the buttock_, is situated close to the
+level of articulation of the leg with the thigh-bone.
+
+
+Muscles of the Anterior Region
+
+First we recall that in man the anterior muscles of the thigh are: the
+triceps cruris, the tensor of the fascia lata, and the sartorius.
+
+=Triceps Cruris= (Fig. 8, 36; Fig. 69, 31; Fig. 70, 41; Fig. 84, 2; Fig.
+87, 3; Fig. 88, 3).--This muscle, which occupies the greater part of the
+space between the pelvis and the anterior aspect of the femur, consists
+of three parts: an external, or vastus externus; an internal, or vastus
+internus; and a median or long portion, or rectus femoris. This division
+accordingly recalls that which characterizes the human triceps cruris.
+Furthermore, as in the case of the latter, the vastus externus and the
+vastus internus take their origin from the shaft of the femur, while the
+long portion arises from the pelvis. The _vastus externus_ arises from
+the external lip of the linea aspera of the femur (or from the external
+border of the posterior surface of this bone in the ox and the horse, in
+which the linea aspera, considerably widened, especially in the latter,
+forms a surface), and from the external surface of the shaft of the
+femur. From this origin its fibres pass downwards and forwards, to be
+inserted into the tendon of the long portion of the muscle and into the
+patella.
+
+In the dog and the cat the vastus externus is the most voluminous of the
+three portions which constitute the triceps muscle. It is covered by the
+fascia lata; but notwithstanding this, its presence is revealed by a
+prominence which occupies the external surface of the thigh, and
+surmounts, in the region of the knee, the more slightly developed one
+which is produced by the knee-cap.
+
+The _vastus internus_, situated on the inner surface of the thigh, takes
+its origin from the corresponding surface of the femur, and proceeds
+towards the patella.
+
+The rectus femoris arises from the iliac bone, above the cotyloid
+cavity; its fleshy body, which is fusiform, and situated in front of and
+between the two vasti muscles, is directed towards the patella, into
+which it is inserted by a tendon, which receives the other two
+portions.
+
+It is covered in front by the tensor of the fascia lata, and contributes
+with the vastus externus to form the upper prominence of the knee.
+
+The ligamentous fibres, which, as in man, unite the knee-cap to the
+tibia, transmit to this latter the action determined by the contraction
+of the triceps. This muscle is an extensor of the leg. Furthermore, the
+rectus femoris, or long portion, acts as a flexor of the thigh.
+
+=Tensor Fascia Lata= (Fig. 68, 34, 36; Fig. 69, 30, 31; Fig. 70,
+40).--This muscle, generally larger in quadrupeds than in man, is flat
+and triangular, and occupies the superior and anterior part of the
+thigh.
+
+It arises from the anterior iliac spine (inferior in carnivora, external
+in the ox and the horse); it is prolonged downwards by an aponeurosis
+(fascia lata) which occupies the external aspect of the thigh, proceeds
+to be inserted into the patella and blend with the aponeurosis of the
+biceps muscle.
+
+It covers the rectus and vastus externus portions of the triceps cruris;
+it is also in relation with the gluteal muscles.
+
+The tensor of the fascia lata flexes the thigh, and serves to raise the
+lower limb as a whole.
+
+=Sartorius= (Fig. 68, 35; Fig. 87, 4, 5; Fig. 88, 5).--This muscle, long
+and flattened, is called by veterinarians _the long adductor of the
+leg_.
+
+Before beginning the study of its position in quadrupeds, it is
+necessary to remember that in man, where the thigh has a form almost
+conical, the sartorius commences on the anterior face of this latter,
+and is directed downwards and inwards to reach the internal surface of
+the knee.
+
+But now let us suppose the thigh flattened from without inwards; there
+will evidently result from this a change in situation with regard to the
+muscle in question. In fact, when this supposition is admitted, it is
+easy to imagine that in a great part of the extent in which the
+sartorius is normally anterior it will become internal. This is why,
+these conditions being realized in quadrupeds, we shall find that, in
+some of them, the sartorius is situated on the aspect of the thigh which
+is turned to the side of the trunk.
+
+In the dog and the cat it arises from the anterior iliac spine, and from
+the half of the border of the bone situated immediately below it; but
+the fibres from this second origin being hidden by the tensor of the
+fascia lata, on the inner side of which they are situated, viewing the
+external surface of the thigh, the muscle seems to arise from the iliac
+spine only.
+
+The sartorius in these animals is divided into two parts, which, in
+general, are placed in contact. One of these fasciculi is anterior; the
+other is situated further back. The first is visible on the anterior
+border of the thigh, in front of the tensor of the fascia lata, but
+below it inclines inwards; in its superior part also, a small extent of
+the internal surface is occupied by it. The second, which, as we have
+said, is situated further back, belongs wholly to the inner surface of
+the thigh; it is this portion which arises from the inferior border of
+the ilium (this is the homologue of the anterior border of the human
+iliac bone).
+
+The two fasciculi then pass towards the knee, being in relation with the
+rectus and the vastus internus of the triceps. The anterior fasciculus
+is inserted into the patella. The posterior unites with the tendons of
+the gracilis (see below) and semi-tendinosus, and then proceeds to be
+inserted into the superior part of the internal surface of the tibia.
+
+On account of their different insertions these two parts receive the
+names of _the patellar sartorius_ and _tibial sartorius_ respectively.
+
+In the ox and the horse the sartorius is still more definitely situated
+on the internal surface of the thigh. Consisting of a single fasciculus,
+representing the tibial sartorius of the cat and the dog, it arises in
+the abdominal cavity from the fascia covering the iliac muscle, then
+passes under the crural arch, and terminates, by an aponeurosis which
+blends with that of the gracilis, on the inner fibres of the patellar
+ligament. In short, the sartorius is of interest to us in the carnivora
+only, and especially on account of its anterior or patellar fasciculus.
+
+It is an adductor of the leg and a flexor of the thigh.
+
+
+Muscles of the Internal Region
+
+The ilio-psoas pectineus and the adductors which we study in man, in
+connection with the internal aspect of the thigh, offer little of
+interest from the point of view of external form in quadrupeds; it is
+for this reason that we will disregard them.
+
+The gracilis alone merits description.
+
+=Gracilis= (Fig. 87, 9; Fig. 88, 6).--Designated in veterinary anatomy
+under the name of _the short adductor of the leg_, this muscle, expanded
+in width, occupies the greater part of the internal surface of the
+thigh, _or flat of the thigh_, as this region is also called. Let us
+imagine, in man, the internal surface of the thigh broader, and the
+internal rectus more expanded, and we shall have an idea of the same
+muscle as it exists in quadrupeds.
+
+The gracilis arises from the ischio-pubic symphysis and from the
+neighbouring regions; thence it is directed towards the leg to be
+inserted into the superior part of the internal surface of the tibia,
+after being united to the tendons of the sartorius and semi-tendinosus.
+We find, accordingly, at this level, an arrangement which recalls the
+general appearance of what in man receives the name of _the goose's
+foot_ (_pes anserinus_).
+
+It is between this muscle and the sartorius, at the superior part of the
+internal surface of the thigh, in the region which recalls the triangle
+of Scarpa, that we are able, especially in the cat and the dog, to see
+the adductor muscles of the thigh. We also partly see there, in these
+animals, the vastus internus and the rectus of the triceps (see Fig.
+87). The gracilis is an adductor of the thigh.
+
+
+Muscles of the Leg
+
+We will divide the leg into three regions: anterior, external, and
+posterior. With regard to the internal region, there are no muscles
+which belong exclusively to it; for it is in great measure formed by the
+internal surface of the tibia, which, as in man, is subcutaneous.
+
+
+Muscles of the Anterior Region
+
+We first note that in the human species the tibialis anticus, extensor
+proprius pollicis, extensor longus digitorum and the peroneous tertius
+or anticus, form the subcutaneous layer of this region. We now proceed
+to study these muscles in quadrupeds.
+
+[Illustration: FIG. 83.--MYOLOGY OF THE HORSE: THE ANTERIOR TIBIAL
+MUSCLE (FLEXOR OF THE METATARSUS), LEFT LEG, ANTERIOR VIEW.
+
+1, Femoral trochlea; 2, tibia; 3, tendinous portion of the tibialis
+anticus; 4, cuboid branch of same; 5, 5, its metatarsal branch; 6,
+fleshy portion; 7, cuneiform branch of its tendon; 8, metatarsal branch
+of the same tendon; 9, extensor longus digitorum (anterior extensor of
+the phalanges turned outwards); 10, peroneus brevis (lateral extensor of
+the phalanges).]
+
+=Tibialis Anticus= (Fig. 83; Fig. 84, 6; Fig. 85, 4; Fig. 87, 10; Fig.
+88, 10, 11).--It is further named by veterinarians the _flexor of the
+metatarsus_.
+
+In the dog and the cat this muscle, which is rather large, arises from
+the external tuberosity of the tibia and from the crest of this bone. In
+its superior part it is flat, but lower down it is thick and produces a
+prominence in front of the tibia. Finally, it becomes tendinous, and
+passes towards the tarsus; thence it is directed towards the inner side
+of the metatarsus, and is inserted into the great-toe, this latter being
+sometimes well developed, but also often merely represented by a small
+bony nodule on which the muscle is then fixed.
+
+In the other animals with which we here occupy ourselves, the tibialis
+anticus presents a complexity which would be incomprehensible unless
+this muscle be first studied in the horse.
+
+In this latter the tibialis anticus consists of two distinct portions,
+placed one in front of the other: a fleshy portion, and a tendinous
+portion running parallel to it.
+
+The muscle is covered, except on its internal part and inferiorly, by a
+muscle with which we will occupy ourselves later on--that is, the common
+extensor of the toes.
+
+The tendinous portion of the tibialis anticus (Fig. 83), especially
+covered by the extensor of the toes, arises from the inferior extremity
+of the femur, from the fossa situated between the trochlea and the
+external condyle; thence it descends towards a groove which is hollowed
+out on the external tuberosity of the tibia, and is directed towards the
+tarsus, where it divides into two branches, which are inserted into the
+cuboid bone and the superior extremity of the principal metatarsal.
+These two parts form a ring through which the terminal tendon of the
+fleshy portion of the same muscle passes.
+
+This fleshy portion, situated behind the preceding, arises from the
+superior extremity of the tibia, on the borders of the groove in which
+the tendinous portion lies; thence it passes downwards for a short
+distance on the inner side of the common extensor of the toes, which
+covers it in the rest of its extent. It ends in a tendon which, after
+passing through the tendinous ring above noticed, divides into two
+branches. One of these branches is inserted into the anterior surface
+of the superior extremity of the principal metatarsal, the other into
+the second cuneiform bone.
+
+[Illustration: FIG. 84.--MYOLOGY OF THE DOG: LEFT HIND-LIMB, EXTERNAL
+ASPECT.
+
+1, Biceps cruris and fascia lata, divided in order to expose the upper
+part of the muscles of the leg; 2, inferior portion of the triceps
+cruris; 3, patella; 4, semi-tendinosus; 5, inferior extremity of the
+femur; 6, tibialis anticus (flexor of the metatarsus); 7, extensor
+longus digitorum (anterior extensor of the phalanges); 8, tibia; 9,
+peroneus longus; 10, peroneus brevis; 11, fifth metatarsal; 12,
+fasciculus detached from the peroneus brevis and passing towards the
+fifth toe; 13, external head of gastrocnemius; 14, tendo-Achillis; 15,
+calcaneum; 16, flexor digitorum sublimis; 17, 17, tendon of the flexor
+digitorum sublimis; 18, flexor longus pollicis (portion of the deep
+flexor of the toes); 19, dorsal muscle of the foot (short extensor of
+the toes).]
+
+In the ox the same two portions of the tibialis anticus exist, but with
+this capital difference--that the anterior portion is fleshy,
+superficial, and blended for a great part of its length with the common
+extensor of the toes.
+
+The portion which corresponds to that which is fleshy in the horse
+arises from the tibia; below, it ends on the inner surface of the
+superior extremity of the metatarsus and the cuneiform bones. That which
+represents the tendinous part, which is also fleshy, as we have just
+pointed out, arises above with the common extensor of the toes, from the
+femur, in the fossa situated between the trochlea and the external
+condyle; whilst below, after having given passage to the tendon of the
+preceding portion, as in the horse, it is inserted into the metatarsus
+and the cuneiform bones.
+
+In the pig, the tibialis anticus presents an arrangement nearly similar
+to that which we have just described.
+
+It seems to us of interest to add that it has been sought to ascertain
+to what muscle of the human leg the tendinous part of the tibialis of
+the horse corresponds--a part which has become fleshy in the pig and the
+ox.
+
+According to some authors, it represents the peroneus tertius; but that
+muscle is situated on the outer side of the common extensor of the toes;
+and here the portion with which it has been compared is placed on the
+inside. It has also been likened to a portion of the common extensor of
+the toes, but it does not pass to the latter. Lastly, it has been
+considered as being the homologue of the proper extensor of the
+great-toe; but why, then, in the ox, which has no great-toe, is it so
+highly developed? Nevertheless, its position and its relations
+sufficiently warrant this method of comprehending it. The tibialis
+anticus is a flexor of the foot. It is also able, in animals in which
+the tarsal articulations allow of the movement, to rotate the foot
+inwards.
+
+[Illustration: FIG. 85.--MYOLOGY OF THE OX: LEFT LEG, EXTERNAL ASPECT.
+
+1, Gluteus maximus and biceps cruris; 2, semi-tendinosus; 3, patella; 4,
+tibialis anticus (flexor of the metatarsus); 5, extensor longus
+digitorum (anterior extensor of the phalanges); 6, fasciculus of the
+extensor longus digitorum, which is considered as the representative of
+the tendinous portion of the tibialis anticus in the horse; 7, peroneus
+longus; 8, peroneus brevis (proper extensor of the external toe); 9,
+external head of gastrocnemius; 10, soleus; 11, tendo-Achillis; 12,
+calcaneum; 13, tendon of the extensor longus digitorum (superficial
+flexor of the phalanges); 14, flexor longus pollicis and tibialis
+posticus (deep flexor of the phalanges); 15, tendon of the superficial
+flexor of the toes; 16, tendon of the deep flexor of the toes; 17,
+suspensory ligament of the fetlock.]
+
+With regard to the tendinous part, called by veterinarians the _cord of
+the flexor of the metatarsus_, it serves, in the horse, to produce the
+flexion of the metatarsus when the knee is already flexed; it thus acts
+in a passive fashion, which is explained by its resistance and the
+position which it occupies in relation to these two articulations.
+
+=Extensor Proprius Pollicis.=--This muscle exists only in the dog and
+the cat, and there in a rudimentary condition.
+
+It is covered by the common extensor of the toes and the tibialis
+anticus, and passes, accompanied by the tendon of this latter muscle, to
+terminate on the second metatarsal, or the phalanx, which articulates
+with it. When the first toe exists in the dog, it is inserted into this
+by a very slender tendon.
+
+=Extensor Longus Digitorum= (Fig. 83, 9; Fig. 84, 7; Fig. 85, 5, 6; Fig.
+86, 4; Fig. 87, 12; Fig. 88, 7).--It is also called by veterinarians
+_the anterior extensor of the phalanges_.
+
+In the dog and the cat this muscle is to be seen in the space limited
+behind by the peroneus longus and in front by the tibialis anticus.
+Above it is covered by this latter. In the lower half of the leg, it is
+also in relation, on the inner side, with the tibialis anticus; but
+behind it is separated from the peroneus longus by the external surface
+of the shaft and inferior extremity of the tibia. This arrangement,
+besides, recalls that which is found in man, the peroneus longus of the
+latter diverging in the same way, at this level, from the common
+extensor, and leaving exposed the corresponding portion of the skeleton
+of the leg.
+
+This muscle, fusiform in shape, arises at its upper part from the
+external surface of the inferior extremity of the femur, then its tendon
+passes into a groove hollowed on the external tuberosity of the tibia.
+The fleshy body which succeeds is directed towards the tarsus, but
+before reaching it is replaced by a tendon. This tendon, at the level of
+the metatarsal bones, divides into four slips, which pass towards the
+toes, and are inserted into the second and third phalanges of the
+latter.
+
+In the horse it covers, to a great extent, the tibialis anticus, so that
+it is the latter which forms the large fusiform prominence especially
+noticeable in the middle region, to which the contour of the anterior
+surface of the leg is due.
+
+[Illustration: FIG. 86.--MYOLOGY OF THE HORSE: LEFT HIND-LIMB, EXTERNAL
+ASPECT.
+
+1, Semi-tendinosus; 2, biceps cruris; 3, patella; 4, extensor longus
+digitorum (anterior extensor of the phalanges); 5, reinforcing band
+arising from the ligament of the fetlock; 6, peroneus brevis (lateral
+extensor of the phalanges); 7, external head of gastrocnemius; 8,
+soleus; 9, tendo-Achillis; 10, calcaneum; 11, tendon of the superficial
+flexor of the toes (superficial flexor of the phalanges); 12, flexor
+longus pollicis and tibialis posticus (deep flexor of the phalanges);
+13, 13, tendon of the superficial flexor of the phalanges; 14, 14,
+tendon of the deep flexor of the phalanges; 15, suspensory ligament of
+the fetlock; 16, principal metatarsal: 17, external rudimentary
+metatarsal.]
+
+It arises above from the inferior extremity of the femur, from the fossa
+situated between the trochlea and the external condyle; therefore, it
+has a common origin with the tendinous portion of the tibialis anticus,
+or flexor of the metatarsus.
+
+The tendon, which at the level of the inferior part of the leg succeeds
+to the fleshy body, passes in front of the tarsus, the principal
+metatarsal, and receives the tendon of the peroneus brevis which we will
+describe later on. It then reaches the anterior surface of the fetlock.
+There it presents an arrangement analogous to that which we have pointed
+out in connection with the anterior extensor of the phalanges--a muscle
+which, in the fore-limbs, corresponds to the common extensor of the
+digits; that is to say, it is inserted, in form of an expansion, into
+the pyramidal prominence of the third phalanx, after having formed
+attachments to the first and second, and having received on each side a
+strengthening band from the suspensory ligament of the fetlock.
+
+In the ox the long extensor of the toes is united above, and for a great
+part of its length, with the portion of the tibialis anticus, which
+represents, albeit in the fleshy state, the tendinous cord of the latter
+in the horse.
+
+In common with this portion, it arises from the inferior extremity of
+the femur. Thence it passes towards the tarsus and divides into two
+fasciculi, internal and external, which are continued by tendons. These
+pass towards the phalanges, and, in case of the common extensor of the
+digits belonging to the fore-limbs, the internal is destined for the
+internal toe, and the external is common to the two toes.
+
+[Illustration: FIG. 87.--MYOLOGY OF THE DOG: LEFT HIND-LIMB, INTERNAL
+ASPECT.
+
+1, Semi-tendinosus; 2, semi-membranosus; 3, triceps cruris (vastus
+internus); 4, sartorius (patellar); 5, sartorius (tibial); 6, patella;
+7, first or middle adductor; 8, small and great adductor united; 9,
+gracilis; 10, tibialis anticus (flexor of the metatarsus); 11, tibia;
+12, tendon of extensor longus digitorum (anterior extensor of the
+phalanges): 13, gastrocnemius, inner head; 14, tendo-Achillis; 15,
+calcaneum; 16, popliteus; 17, superficial flexor of the toes; 18, flexor
+longus pollicis (portion of the deep flexor of the toes); 19, flexor
+longus digitorum (portion of the deep flexor of the toes); 20, tendon of
+the tibialis posticus.]
+
+[Illustration: FIG. 88.--MYOLOGY OF THE HORSE: LEFT HIND-LEG, INTERNAL
+ASPECT.
+
+1, Semi-tendinosus; 2, semi-membranosus; 3, triceps cruris (vastus
+internus); 4, patella; 5, sartorius; 6, gracilis; 7, extensor longus
+digitorum common extensor of the toes (anterior extensor of the
+phalanges); 8, tendon of the preceding muscle; 9, reinforcing band given
+off by the suspensory ligament of the fetlock; 10, tibialis anticus
+(flexor of the metatarsus), its tendinous portion; 11, tibialis anticus
+(flexor of the metatarsus), its fleshy portion; 12, cuneiform branch of
+the tendon of this fleshy portion; 13, internal head of gastrocnemius;
+14, popliteus; 15, tendon of the flexor brevis digitorum (superficial
+flexor of the phalanges); 16, flexor longus pollicis and tibialis
+posticus (deep flexor of the phalanges); 17, flexor longus digitorum
+(oblique flexor of the phalanges); 18, 18, tendon of the superficial
+flexor of the phalanges; 19, 19, tendon of the deep flexor of the
+phalanges; 20, suspensory ligament of the fetlock; 21, principal
+metatarsal; 22, internal rudimentary metatarsal.]
+
+In the pig the general arrangement of the muscle is similar, but the
+tendons end in a manner which is a little more complicated. Apart from
+the fasciculi which correspond to the tendinous portion of the tibialis
+anticus (fleshy here, as in the ox), the long extensor of the toes at
+the level of the tarsus divides into three tendons: the internal goes to
+the great internal toe; the middle bifurcates in the upper part of the
+digital portion of the foot, and each of its branches goes towards one
+of the great-toes; the external divides to pass towards each of the two
+small toes, and towards the great ones; but this latter disposition is
+not constant.
+
+By its contraction the muscle which we have just studied extends the
+phalanges and flexes the foot.
+
+=Peroneus Tertius.=--This muscle is not found in domestic quadrupeds.
+
+We should remember, nevertheless, that certain authors consider as
+representing it the tendinous portion of the anterior tibial of the
+horse, or the corresponding portion now fleshy, of the same muscle in
+the pig and the ox. It is by reason of this fact that it is called the
+third peroneal, notwithstanding that in the numerical order of the
+peroneals it is rather the first.
+
+But that which still further complicates this question of nomenclature
+is that some authors give this name of third to a peroneal which, in the
+carnivora, is situated more definitely in the group of external muscles
+(see below, =Short Lateral Peroneal=).
+
+
+Muscles of the External Region
+
+In man, two muscles constitute this region; they are the peroneus longus
+and peroneus brevis.
+
+=Peroneus Longus= (Fig. 84, 9; Fig. 85, 7).--This muscle does not exist
+in the domestic animals; only in the flesh-eaters, the pig and the ox
+excepted.
+
+It is in relation superiorly with the tibialis anticus, and inferiorly
+with the common extensor of the toes; in the ox, it is in contact with
+this latter muscle throughout its whole length.
+
+The peroneus longus arises from the external tuberosity of the tibia;
+towards the middle of the leg it is replaced by a tendon. This proceeds
+towards the tarsus, but previously it passes between the tibia and
+fibula. In the ox it is situated in front of the coronoid tarsal bone;
+we recollect that this bone is regarded as representing the inferior
+extremity of the fibula (see p. 97). Then it passes into a groove
+belonging to the cuboid bone or to the cuboido-scaphoid bone in the ox,
+traverses obliquely the posterior aspect of the tarsus, and is inserted
+into the rudimentary bone which represents the first toe; or, if this
+does not exist, into the innermost of the metatarsal bones.
+
+This muscle is an extensor of the foot. It also rotates it outwards in
+the animals in which the articulation permits this latter movement.
+
+=Peroneus Brevis= (Fig. 83, 8; Fig. 83, 10; Fig. 84, 10; Fig. 86,
+6).--In the dog and the cat, this muscle is covered in part by the
+peroneus longus, and arises from the inferior half of the tibia and the
+fibula; at the level of the tarsus it becomes tendinous, passes into a
+groove hollowed out on the external surface of the inferior extremity of
+the fibula, and terminates on the external aspect of the superior
+extremity of the fifth metatarsal. A little before this insertion it
+crosses the tendon of the long peroneal in passing to the outer side of
+the latter.
+
+To the short peroneal muscle is found annexed a very thin fasciculus
+which lies upon it. This fasciculus arises from beneath the head of the
+fibula, and is soon replaced by a thin tendon, which, accompanying that
+of the short peroneal, proceeds towards the foot, after having traversed
+the groove in the inferior extremity of the fibula; passes along by the
+fifth metatarsal (Fig. 84, 12); blends at the level of the first phalanx
+of the fifth toe with the corresponding tendon of the long extensor of
+the toes, and partakes of the insertions of this tendon.
+
+This fasciculus is designated by some authors under the name of the
+peroneal of the fifth toe, or the proper extensor of the same toe. But
+what makes still further complications is that other authors regard it
+as an anterior, or third, peroneal. Now, these names are those which
+other anatomists have applied to the fasciculus of the anterior tibial,
+which, in the pig and the ox, is fused in part with the long extensor of
+the toes. Hence there results a confusion which is truly regrettable.
+
+In brief, we can, without inconvenience, consider it as a fasciculus of
+the short peroneal muscle.
+
+We sometimes find in man, but abnormally, an arrangement which partly
+recalls that which we have just indicated. It consists in a duplication
+of the tendon of the short peroneal, one of the branches of which goes
+to the fifth metatarsal, and the other to the fifth toe; it is sometimes
+a single fasciculus which goes to the phalanges of this latter. We have
+met with examples of these anomalies.[31] In the pig, the short peroneal
+is situated on the same plane as the long. It consists of two clearly
+distinct fasciculi, which arise from the fibula. The tendon of the
+anterior fasciculus proceeds to the great external toe--that is to say,
+the fourth, of which it is the proper extensor. The posterior fasciculus
+terminates on the small external toe, the fifth, of which it is in like
+manner the extensor.
+
+  [31] Édouard Cuyer, 'Anomalies, Osseous and Muscular' (_Bulletins de
+       la Société d'Anthropologie_, Paris, 1891).
+
+In the ox, the fleshy fibres of the short peroneal arise from a fibrous
+band which replaces the fibula, and from the external tuberosity of the
+tibia. Situated behind the long peroneal and on the same plane, it
+terminates in a tendon which appears at the level of the inferior part
+of the leg; it passes in front of the canon, and is inserted into the
+external toe, of which it is the proper extensor.
+
+In the horse, it is the sole representative of the peroneal muscles, and
+veterinary anatomists have given it the name of _the lateral extensor of
+the phalanges_.
+
+Its fleshy body arises above from the external lateral ligament of the
+knee-joint, and from the whole length of the fibula. In the middle third
+of the leg it is narrowed; lower down it is replaced by a tendon. This
+is lodged in a groove hollowed on the external surface of the inferior
+extremity of the tibia; then after passing along the external surface of
+the tarsus, it is directed forward, and proceeds to blend towards the
+middle of the canon-bone with the tendon of the long extensor of the
+toes, or anterior extensor of the phalanges, of which it shares the
+insertions. It extends the phalanges into which it is inserted. It also
+flexes the foot.
+
+
+Muscles of the Posterior Region
+
+It will not be unprofitable to recall to mind that, in man, the muscles
+of this region are arranged in two layers: a superficial layer
+consisting of the gastrocnemius and soleus, to which is added a muscle
+of little importance, the plantaris, and a deep layer formed by four
+muscles--the popliteus, flexor longus digitorum, tibialis posticus, and
+flexor longus pollicis.
+
+The gastrocnemius and soleus, independent in their upper portion, unite
+below in a common tendon; they thus form also a triceps muscle, which we
+designate under the name of the triceps of the leg, or triceps suralis,
+because it forms the elevation of the calf of the leg (from _sura_,
+calf).
+
+=Gastrocnemius= (Fig. 83, 9, 11; Fig. 84, 13, 14; Fig. 86, 7, 9; Fig.
+88, 13).--The external and internal heads of the gastrocnemius, distinct
+from one another only in their upper portion, arise from the shaft of
+the femur, above the condyles, on the borders of the popliteal surface,
+to a relatively considerable extent in the great quadrupeds.
+
+At this level they are situated in the popliteal region--that is to say,
+in the space limited externally by the biceps, and internally by the
+semi-tendinosus. But as they descend to a rather low level on the leg in
+quadrupeds, and especially in carnivora, they do not, properly speaking,
+determine a projection of the calf of the leg. However, they pass from
+this region but to be soon continued by a tendon--the tendo-Achillis,
+which is inserted into the calcaneum.
+
+Now, the region of the tarsus is called by veterinarians _the ham_, the
+posterior surface of which is angular, because of the oblique direction
+of the leg with regard to the vertical direction of the metatarsus and
+the presence of the calcaneum; the prominence which this surface
+presents has received the name of _the point of the ham_, and the tendon
+which ends there that of _the cord of the ham_.
+
+But the tendo-Achillis does not alone form this cord. Indeed, as we will
+soon see, the tendon of the superficial flexor of the toes takes part in
+its formation.
+
+We may add, with regard to the tendo-Achillis, that it is more clearly
+perceived as an external feature, because the skin sinks in front of it,
+as it does in man, over the lateral parts of the region which it
+occupies.
+
+The gastrocnemius, when it contracts, extends the foot on the leg.
+
+It serves to maintain the tibio-tarsal angle in the standing position,
+and during walking, to determine the steadying of the hind-limbs, which
+then, after the fashion of a spring, project the body forward.
+
+By an analogous movement they take part in the posterior projection of
+the hind-limbs in the act of kicking; but they are not the only ones to
+act in this case, the muscles of the buttock and thigh also being
+brought into play.
+
+=Soleus= (Fig. 83, 10; Fig. 86, 8).--This muscle, much less developed in
+quadrupeds than in man, does not exist in the dog.
+
+With regard to the soleus in the pig, Professor Lesbre says: 'Meckel
+denied its existence; we, however, believe that it is united to the
+external head of the gastrocnemius, its origin being transferred to the
+femur.'[32]
+
+  [32] F. X. Lesbre, 'Essai de Myologie comparée de l'homme et des
+       mammifères domestiques en vue d'établir une nomenclature unique
+       et rationelle,' Lyon, 1897, p. 169.
+
+But in animals in which it exists, this muscle, of but little
+importance, occupies the outer side of the leg. It arises above from the
+external tuberosity of the tibia, and terminates below in a tendon which
+is united with that of the gastrocnemius.
+
+The soleus has the same action as these latter.
+
+=Plantaris.=--In quadrupeds this muscle is blended with the superficial
+flexor of the toes, which we will study afterwards.
+
+=Popliteus= (Fig. 87, 16; Fig. 88, 14).--In man, this muscle, which
+occupies the posterior surface of the tibia, above the oblique line, is
+completely covered by the gastrocnemius.
+
+In quadrupeds, where it is more voluminous, it projects internally
+beyond the gastrocnemius, so that it is seen in the internal and
+superior part of the region of the superficial layer of muscles,
+immediately behind the internal surface of the tibia, which, as we know,
+is subcutaneous.
+
+The popliteus arises from the external surface of the external condyle
+of the femur. Thence its fibres which diverge pass to be inserted into
+the superior part of the posterior surface and of the internal border of
+the tibia. It is in this latter region that it projects beyond the
+gastrocnemius, but we may add that there it is more or less covered by
+the semi-tendinosus.
+
+It flexes the leg, and rotates it forwards.
+
+=Superficial Flexor of the Toes= (Fig. 83, 13, 15; Fig. 84, 17; Fig. 86,
+11, 13, 13; Fig. 87, 17; Fig. 88, 15, 18, 18).--In man, the homologue of
+this muscle is found in the sole of the foot. It is called _the short
+flexor of the toes_. It arises from the calcaneum, and passes to the
+four outer toes. In quadrupeds, it rises as high as the back of the
+knee, and is found blended with the plantaris.
+
+Further designated by the name of _the superficial flexor of the
+phalanges_, covered in part by the gastrocnemius, with which it is in
+relation for a great part of the course which it traverses, this muscle
+arises from the posterior surface of the femur, on the external branch
+of the inferior bifurcation of the linea aspera. In the horse, this
+origin takes place in a depression situated above the external condyle,
+in the supracondyloid fossa. Then it accompanies the gastrocnemius, and
+becomes tendinous where the tendo-Achillis commences. It then winds
+round the latter in placing itself on its inner side, then on its
+posterior surface, and reaches the calcaneum. It accordingly
+contributes, as we have already pointed out, to form the cord of the
+ham. After having become expanded, and having covered as with a sort of
+fibrous cap the bone of the heel, it descends behind the metatarsus, and
+presents there an arrangement analogous to that which we pointed out in
+connection with the superficial flexor of the digits--that is, it
+contributes to form the _tendon_. This prominence, in the form of a
+cord, we see behind the canon-bone in solipeds and ruminants. It
+finally terminates in the same way as the muscle with which we have
+compared it (see p. 197).
+
+In the horse, its fleshy body is but slightly developed, so that its
+tendon alone is specially visible in the superficial muscular layer, but
+in the dog and the cat it is large. Hence it results that its fleshy
+body appears on each side of the inferior half of the gastrocnemius, and
+produces an elevation which recalls that which the soleus produces on
+each side of the same muscles in the human species.
+
+The muscles which follow form, with the popliteus, which we have already
+studied, the deep layer of the posterior region of the leg.
+
+=Flexor Longus Digitorum= (Fig. 87, 19; Fig. 88, 17).--This muscle, in
+man, is the only common flexor of the toes belonging to the muscles of
+the leg.
+
+In comparison with the preceding muscle, it is a deep flexor.
+Veterinarians have given it the name of _the oblique flexor of the
+phalanges_.
+
+Visible on the internal aspect of the superficial layer of the muscles
+of the leg, this muscle arises above from the posterior surface of the
+external tuberosity of the tibia, becomes tendinous, passes towards the
+metatarsus, and blends with the tendons of the posterior tibial and the
+long proper flexor of the great-toe. In the dog and the cat it is
+blended with this latter only.
+
+=Tibialis Posticus= (Fig. 85, 14; Fig. 86, 12; Fig. 87, 20; Fig. 88,
+16).--This muscle arises from the external tuberosity of the tibia, and
+from the head of the fibula. Thence it passes to the tarsus, and
+terminates in different fashion in carnivora and other quadrupeds.
+
+In the dog and the cat, it is inserted into the ligamentous apparatus of
+the tarsus, or into the base of the second metatarsal.
+
+In the other quadrupeds with which we are here occupied it is blended
+with the long proper flexor of the great-toe.
+
+It is accordingly in the carnivora that the mode of termination of the
+tibialis posticus most nearly resembles that of this same muscle in the
+human species. From this independence there results a special action.
+
+It is an adductor and internal rotator of the foot.
+
+=Flexor Longus Pollicis= (Fig. 84, 18; Fig. 85, 14; Fig. 86, 12; Fig.
+87, 18; Fig. 88, 16).--This muscle, as that in man, is the most external
+of the deep layer of the leg. It is on the external aspect of the latter
+we perceive it, between the peroneals and the gastrocnemius or
+tendo-Achillis.
+
+It arises from the fibula and tibia, and is thence directed towards the
+tarsus. It unites with the long common flexor of the toes to form with
+it _the deep flexor of the phalanges_, of which it is the principal
+fasciculus. We may add that in the dog and the cat the posterior tibial
+remains independent of this latter, but that in the pig, ox, and horse
+the posterior tibial is united to the preceding to form with them the
+deep flexor muscle.
+
+Thus constituted, the deep flexor goes towards the phalanges, where it
+terminates as the deep flexor of the digits of the fore-limbs (see p.
+197). In animals possessed of a canon it contributes to form the
+_tendon_ (Fig. 85, 16; Fig. 86, 14, 14; Fig. 88, 19, 19).
+
+
+Muscles of the Foot
+
+We must remember that on the dorsal surface of the foot in man we find
+but a single muscle--the dorsalis pedis. The remaining subcutaneous
+structures of this region consist of the tendons of the anterior muscles
+of the leg which occupy this dorsal aspect.
+
+=Dorsalis Pedis= (Fig. 84, 19).--Also called the extensor brevis
+digitorum, the dorsalis pedis muscle is found in all domestic
+quadrupeds; but its development is so much the less as the number of
+digits is more reduced.
+
+In the dog and the cat it arises from the calcaneum, and is inserted
+into the three internal toes (the first toe excepted) by uniting with
+the corresponding tendons of the common extensor.
+
+In the pig its disposition is analogous.
+
+As for the dorsalis pedis of the ox and the horse, it is extremely
+rudimentary, and occupies the superior part of the canon. It is a small,
+fleshy body, situated on the anterior surface of the metatarsus, which
+arises from the calcaneum, whence it passes to unite at its inferior
+extremity with the tendon of the extensor of the phalanges.
+
+As regards the muscles of the sole of the foot, we think it unnecessary
+to occupy ourselves at any length with them because of their slight
+importance with regard to external form.
+
+We will only recall that in the median portion of this plantar surface
+we find in man the short flexor of the toes, which in quadrupeds arises
+higher up, from the posterior surface of the femur; that it belongs to
+the muscles of the leg; and that it forms the superficial flexor of the
+toes, which we have already studied.
+
+We may further add that the suspensory ligament of the fetlock in
+ruminants and solipeds represents, as in the fore-limbs, the
+interosseous muscles.
+
+
+MUSCLES OF THE HEAD
+
+We will divide these muscles into two categories: masticatory and
+cutaneous.
+
+
+Masticatory Muscles
+
+The muscles of this group which specially interest us are the masseter
+and the temporal. As regards the pterygoids, since they are situated
+within the borders of the inferior maxillary bone, and consequently do
+not reach the surface, we shall not require to occupy ourselves with
+them here.
+
+=Masseter= (Fig. 89, 2; Fig. 90, 1; Figs. 91, 92).--For those who have
+studied the masseter of man, it is not difficult to recognise that of
+quadrupeds. Nevertheless, the particular aspect which it presents in
+different species gives to its study a certain interest.
+
+Arising from the zygomatic arch, and passing downwards and backwards, it
+is inserted into the external surface of the ramus of the mandible and
+into its angle.
+
+Its posterior border is in relation with the parotid gland (Fig. 90, 14;
+Figs. 91, 92), this gland being situated between the corresponding
+border of the lower jaw bone and the transverse process of the atlas.
+Such are the general characters; the following are the particular ones:
+
+In the carnivora it is thick and convex. In the horse it is flat, but
+more expanded; it forms the _flat of the cheek_. In the ox it is flat,
+as in the latter; but, while being less thick, it is more prolonged in
+the vertical direction.
+
+The form of the osseous parts which give it origin is, besides, in
+relation with these differences, and explains the peculiar characters
+which the masseter presents.
+
+[Illustration: FIG. 89.--MYOLOGY OF THE DOG: MASTICATORY MUSCLES (A
+DEEPER DISSECTION THAN THAT SHOWN IN FIG. 90).
+
+1, Zygomatic arch; 2, masseter; 3, temporal exposed by the suppression
+of the auricular and occipital muscles and the pinna of the ear; 4,
+auditory canal; 5, inferior maxillary bone; 6, digastric.]
+
+Indeed, in the dog and the cat the zygomatic arch, strongly convex,
+springs up in a marked manner from the plane of the lateral aspects of
+the skull.
+
+In the horse the same arch, less prominent externally, is prolonged by a
+rectilinear crest on the superior maxillary bone, where it is continued
+in forming the zygomatic or maxillary spine.
+
+In the ox the same crest ascends a good way towards the inferior margin
+of the orbit in a curved direction with the concavity inferior, to
+redescend afterwards on the external surface of the superior maxilla.
+
+The masseter is an elevator of the lower jaw. It acts, above all, as in
+the human species, in the process of mastication.
+
+=Temporal Muscle= (Fig. 89, 3).--The development of the temporal is in
+proportion to the energy of the movements of elevation which the lower
+jaw has to execute.
+
+It arises from the temporal fossa, and is inserted into the coronoid
+process of the inferior maxilla.
+
+Its development, enormous in the carnivora, is such that the muscle
+projects beyond its fossa. It is less voluminous in the horse, and still
+less so in the ox. In the latter, indeed, the temporal fossa, although
+deep, is of small extent (see Fig. 62, p. 119); the frontal bone being
+large, it is found to be thrown back on the lateral walls of the
+cranium, below the osseous processes which support the horns and
+overhang the fossa in question, as well as the muscle which it contains.
+
+It is covered by the auricular muscles, and by the base of the pinna of
+the ear.
+
+Like the masseter, the temporal is an elevator of the lower jaw.
+
+
+Cutaneous Muscles of the Head
+
+=Occipito-Frontalis.=--The epicranial aponeurosis is extremely thin. In
+the dog the occipital muscle occupies the superior part of the head; it
+overlies the temporal muscle.
+
+With regard to the frontal muscle, which is of great extent in the ox
+(Fig. 91, F), it is represented in the horse and the carnivora by a
+small fleshy fasciculus only, the _fronto-palpebral muscle_, similar to
+the superciliary muscle. This, occupying the superior and internal part
+of the border of the orbit, ends by blending its fibres with those of
+the orbicular muscle of the eyelids at the region of the eyebrow.
+
+=Orbicularis Palpebrarum= (Fig. 90, 2; Figs. 91, 92).--This annular
+muscle surrounds the palpebral orifice, and takes its origin on the
+internal part of the orbital region. In the horse it arises, by a small
+tendon, from a tubercle which occupies the external surface of the os
+unguis, or lachrymal bone.
+
+This muscle determines the narrowing and closure of the palpebral
+orifice.
+
+=Pyramidalis Nasi.=--The pyramidal muscle is not found in the domestic
+animals. It appears to be blended with the internal elevator of the
+upper lip and wing of the nose; this is easy of comprehension if we bear
+in mind the relative position of these two muscles in the human species.
+
+[Illustration: FIG. 90.--MYOLOGY OF THE DOG: MUSCLES OF THE HEAD.
+
+1, Masseter; 2, orbicularis palpebrarum; 3, zygomaticus major; 4,
+lachrymal (this muscle is sometimes described under the name of the
+small zygomatic); 5, levator labii superioris proprius; 6, levator
+labii superioris alæque nasi; 7, caninus; 9, buccinator; 11,
+zygomatico-auricularis; 12, external temporo-auricularis; 14, parotid
+gland; 15, parotido-auricularis; 16, inferior maxillary bone; 17,
+digastric.]
+
+=Corrugator Supercilii.=--This muscle is represented by the
+fronto-palpebral muscle noticed above, which is by some regarded as a
+vestige of the frontal.
+
+=Zygomaticus Major= (Fig. 90, 3; Figs. 91, 92).--This is the
+_zygomatic-labial_ of veterinarians. This muscle is of an elongated
+form, and has a ribbon-like aspect.
+
+In the dog and the cat it arises from the base of the pinna of
+the ear, from the portion of this base which bears the name of
+scutiform cartilage. (With regard to this cartilage, see p. 242,
+=Zygomatico-auricularis=.) From this it is directed downwards and
+forwards, to terminate, after having crossed the masseter, on the deep
+surface of the skin of the corresponding labial commissure.
+
+This mode of termination is the same in the ox and the horse; but where
+the muscle differs is at the level of its upper extremity. There it
+ascends less than in the carnivora. In the ox it arises from the
+zygomatic arch in the neighbourhood of the temporo-maxillary
+articulation; in the pig and the horse its origin is still lower, on the
+surface of the masseter, close to the maxillary spine.
+
+When it contracts, it draws upwards the labial commissure.
+
+Now, in man, we remember, it is the great zygomatic that, by an action
+of the same kind, determines the essential characters of the expression
+of laughing.
+
+There is, accordingly, a connection to be established between those
+displacements which are similar and the analogy of facial expression
+which necessarily results from them.[33]
+
+  [33] Édouard Cuyer, 'The Mimic,' Paris, 1802.
+
+=Zygomaticus Minor= (Fig. 90, 4; Figs. 91, 92).--The existence of this
+muscle has not been clearly demonstrated. Nevertheless, Straus-Durckheim
+noted its presence in the horse, and described it as 'a muscle arising
+by two heads, of which one, the superior, arises from the malar bone
+below the orbit, and passes downwards and forwards over the
+fibro-adipose layer which supports the moustache. The second, the
+inferior, arises from the alveolar border in front of the second molar
+tooth, and passes forward to be inserted into the same fibro-adipose
+layer.'[34]
+
+  [34] H. Straus-Durckheim, 'Anatomie descriptive et comparative du
+       chat,' Paris, 1845, t. ii., p. 210.
+
+In connection with other quadrupeds, it is described by certain authors
+as a very thin muscle, arising below the cavity of the orbit, where it
+is blended with the fibres of the internal elevator of the upper lip and
+the ala of the nose; thence it proceeds to terminate below by uniting
+with the subcutaneous muscle. But this muscle is regarded by other
+authors as the lachrymal muscle, which does not exist in this state in
+man, but of which the development is particularly remarkable, as to
+extent, in the ox, in which it descends as far as the buccinator.
+
+According to other authors, some of the fibres of this muscle constitute
+the small zygomatic.
+
+[Illustration: FIG. 91.--MYOLOGY OF THE OX: MUSCLES OF THE HEAD.
+
+1, Masseter; 2, orbicularis palpebrarum; F, frontalis; 3, zygomaticus
+major; 4, lachrymal (this muscle is sometimes described under the
+name of small zygomatic); 5, levator labii superioris proprius; 6,
+levator labii superioris alæque nasi; 7, levator anguli oris or
+caninus; 8, orbicularis oris; 9, buccinator; 10, maxillo-labial; 11,
+zygomatico-auricularis; 12, external temporo-auricularis; 14, parotid
+gland; 15, parotido-auricularis; 16, inferior maxillary bone.]
+
+=Levator Labii Superioris Proprius= (Fig. 90, 5; Figs. 91, 92).--Also
+named by veterinarians the _supramaxillo-labial_, or again, the _proper
+elevator of the upper lip_, this muscle arises from the external surface
+of the superior maxillary bone, passes under the superficial elevator,
+which we shall study in the succeeding paragraph, and goes to be
+inserted into the thickness of the lip, to which its name indicates that
+it belongs.
+
+The peculiarities of this muscle in different animals are the following:
+
+In the dog and the cat it arises behind the infra-orbital foramen.
+
+In the pig it arises from a depression below the orbital cavity, and its
+fleshy body is terminated in front by a strong tendon in the upper part
+of the snout, in which it divides into fasciculi.
+
+In the ox it arises from the maxillary spine.
+
+In the horse it arises below the orbital cavity; then, after having
+crossed the superficial elevator, it ends in a tendinous expansion,
+situated in the median line between the nasal fossæ. This expansion
+divides into fasciculi, which end in the thickness of the upper lip.
+
+By the contraction of this muscle, the lip is raised, on one side only,
+if a single muscle contracts, or in its whole extent, if the two muscles
+act simultaneously.
+
+=Internal Elevator (or Superficial) of the Upper Lip and the Wing of the
+Nose= (_levator labii superioris alæque nasi_) (Fig. 90, 6; Figs. 91,
+92).--This is the muscle veterinarians designate _the supranaso-labial_.
+
+Arising from the frontal and nasal bones, it thence passes towards the
+upper lip, where it is inserted as well as into the wing of the nose.
+
+In the ox it is united above with the frontal muscle, and below is
+divided into two fasciculi, between which pass the elevator described
+above and the canine muscle.
+
+In the horse it is also divided into two fasciculi; but the arrangement
+is the opposite as regards, their relations with neighbouring muscles,
+in this animal and in the preceding.
+
+In the ox the external fasciculus is covered by the external elevator
+and the canine, which pass under the internal fasciculus; in the horse
+the deep elevator passes under the two fasciculi, and the canine passes
+under the external bundle, and afterwards covers the internal.
+
+In the pig, the internal elevator is wanting.
+
+As its name indicates, it raises the upper lip and the wing of the
+nose.
+
+=Transversus Nasi.=--In the horse this muscle, which is very thin, is
+situated on the dorsum of the nose, and proceeds to be inserted into the
+cartilaginous skeleton of the nostrils. In the pig, it occupies an
+analogous situation. It does not exist in the ox or in carnivora. The
+transversus nasi is a dilator of the nostrils.
+
+[Illustration: FIG. 92.--MYOLOGY OF THE HORSE: MUSCLES OF THE HEAD.
+
+1, Masseter; 2, orbicularis palpebrarum; 3, zygomaticus major; 4,
+lachrymal (this muscle is sometimes described under the name of the
+small zygomatic); 5, external elevator (or deep) of the upper lip and
+ala of the nose; 6, internal elevator (or superficial) of the upper lip
+and of the ala of the nose; 7, levator anguli oris or caninus; 8,
+orbicularis oris; 9, buccinator; 10, maxillo-labialis; 11,
+zygomatico-auricularis; 12, temporo-auricularis externus; 13,
+cervico-auricularis; 14, parotid gland; 15, parotido-auricularis; 16,
+inferior maxillary bone.]
+
+=Caninus= (Fig. 90; Figs. 7, 91, 92).--This is the muscle called by
+veterinarians _the great supramaxillo-nasal_.
+
+In the dog and the cat it is situated below the inferior border of the
+external elevator of the upper lip, of which it follows the direction.
+It arises, as does this latter, from the external surface of the
+maxilla, and goes also to terminate in the upper lip by blending with
+the internal elevator of this lip and of the alæ of the nose. It raises
+the upper lip.
+
+In the ox, it arises from the maxillary spine, and then divides into
+three parts; the superior passes under the internal portion of the
+internal elevator of the upper lip and the alæ of the nose, and goes
+into the nostril; whilst the two others, situated lower down, terminate
+in the upper lip.
+
+In the pig, it is formed of two superimposed fasciculi, which arise from
+the spine of the maxilla and the impressions in front of it. These two
+fasciculi terminate in the snout, which they move laterally.
+
+In the horse, it is situated at a certain distance from the external
+elevator; in the preceding animals it is in contact with the latter.
+Arising behind from the external surface of the maxilla, in front of the
+maxillary spine, it is directed towards the anterior part of the face,
+passes under the external portion of the internal elevator (it is the
+opposite of this in the ox), and proceeds, on expanding, to terminate in
+the skin of the nostril. By its contraction it dilates the latter.
+
+=Orbicularis Oris= (Fig. 91, 8; Fig. 92).--This muscle, very fleshy in
+the solipeds and the ruminants, is arranged as a ring round the buccal
+orifice, in the thickness of the lips, where it is blended with the
+other muscles of this region.
+
+Having for its function the narrowing of the orifice it surrounds, it
+acts during suction and in the prehension of food.
+
+=Triangularis Oris.=--This muscle does not exist in domestic quadrupeds.
+
+=Quadratus Menti.=--In the pig and the carnivora, it arises from the
+anterior part of the body of the inferior maxillary bone, and passes at
+the other end to terminate in the corresponding portion of the lower
+lip, which it depresses by its contraction.
+
+In the ox and the horse this muscle does not exist; it is replaced for
+the depression of the lower lip, which it affects in other animals, by
+supplemental fibres of the buccinator.
+
+=The Prominence of the Chin.=--Below the lower lip in the horse is
+situated the so-called _prominence of the chin_, limited posteriorly by
+the _beard_, a depressed region which gives point to the curb of the
+bridle.
+
+The prominence, which also exists in the ox, is a fibro-muscular pad
+which blends with the orbicular muscle of the lips, and receives on its
+superior aspect the insertion of the two muscles (_levator menti_) by
+which it is suspended. These arise, above, on each side of the symphysis
+of the inferior maxillary bone. They raise the lower lip with force, and
+they are the agents which, as we can sometimes observe in the horse,
+make it click against the upper lip, suddenly projecting it upwards.
+This action sometimes becomes a habit, and its continuance constitutes a
+vice.
+
+A corresponding structure is found in the pig and in the carnivora, but
+in them it does not produce an external prominence such as we have
+described.
+
+=Buccinator= (Fig. 90, 9; Figs. 91, 92).--Further designated by the name
+of _alveolo-labial_, this muscle is situated on the lateral portions of
+the face, in the thickness of the cheeks. It consists of two layers, one
+superficial and the other deep.
+
+The deep portion arises from the portion of the alveolar border of the
+superior maxillary bone which corresponds to the molar teeth, and from
+the anterior border of the ramus of the mandible. Thence it is directed
+forwards, passes under the superficial layer, and blends with the fibres
+of the orbicular muscle of the lips. To this part of the buccinator some
+authors give the name of molar muscle.
+
+The superficial portion is formed by fibres which pass from the alveolar
+border of the superior maxillary bone to the corresponding border of the
+opposite bone. It is very highly developed in the herbivora.
+
+This muscle acts especially during mastication; it serves to press back
+again under the molar teeth the portions of food which fall outside the
+dental arch.
+
+In the pig, the ox, and the horse, a muscle which is considered as
+supplemental to the buccinator is placed along the inferior border of
+the latter.
+
+This muscle, which we describe separately under the names of
+_maxillo-labialis_ (Fig. 91, 10; Fig. 92) and _depressor of the lower
+lip_, is clearly distinct from the buccinator, especially in the horse.
+It arises, behind, with the deep layer of the muscle to which it is
+annexed, from the anterior border of the ramus of the lower jaw; in
+front it terminates in the thickness of the lower lip.
+
+In the ox, it is more intimately united with the buccinator.
+
+It depresses the lip to which it is attached, and displaces it laterally
+when it acts on one side only.
+
+In the human species, the pinna of the ear being generally immobile, the
+muscles which belong to it are, very naturally, considerably atrophied.
+Accordingly, the auricular muscles, anterior, superior, and posterior,
+are reduced to pale and thin fleshy lamellæ, whose action is revealed in
+certain individuals, only in a way which may be said to be abnormal.
+
+It is not the same in quadrupeds. The pinna of the ear is extremely
+mobile, and its displacements have a real value from the point of view
+of physiognomical expression. It is therefore necessary to review the
+muscles which move this pinna without giving them, at the same time,
+more importance than they merit, since in themselves they do not
+determine the formation of surface reliefs, which are sufficiently
+apparent.
+
+Notwithstanding that for certain of these muscles it is possible to
+trace their analogy with those of the auricular region of man, it is
+very difficult, because of their complexity, to trace this analogy for
+all. This is why we shall not be able here, as we have done for the
+other muscles of the subcutaneous layer, to give at the head of each
+paragraph the name of a human muscle, and then to group in the same
+paragraph the muscles which correspond to it in different quadrupeds.
+Therefore the nomenclature and the divisions adopted for these latter
+must serve us as a base or starting-point.
+
+Because the pinna of the horse's ear is so very mobile, we will first
+begin with a study of its auricular muscles.
+
+=Zygomatico-auricularis= (Fig. 92, 11).--This muscle, which is formed of
+two small bands of fleshy fibres, arises from the zygomatic arch in
+blending with the orbicular muscle of the eyelids; thence it is
+directed towards the base of the pinna of the ear, and is inserted into
+this base, and also into the cartilaginous plate situated in front of
+and internal to this, and resting on the surface of the temporal muscle;
+this is the scutiform cartilage.
+
+The zygomatico-auricularis, which we look on as the homologue of the
+anterior auricular of man, draws the pinna of the ear forwards.
+
+=Temporo-auricularis Externus= (Fig. 92, 12).--This, which is thin and
+very broad, covers the temporal muscle.
+
+It arises from the whole extent of the parietal crest, blending in this
+plane, in its posterior half, with the muscle of the opposite side.
+Thence it is directed outwards towards the pinna of the ear, and is
+inserted into the internal border of the scutiform cartilage and on the
+inner side of the concha--that is to say, of the conchinian
+cartilage--which forms the principal part of the pinna. We are
+supposing, in the description of the muscles which move it, that this
+pinna has its opening directed outwards.
+
+The external temporo-auricular, which recalls, from its situation, the
+superior auricular of man, is an adductor of the ear; besides, it causes
+it to describe a movement of rotation from without inwards, so as to
+direct its opening forwards.
+
+=Scuto-auricularis Externus.=--This muscle may be considered as
+supplementary to the external temporo-auricular; the concha fasciculus
+of this latter partly covers it.
+
+Extending from the scutiform cartilage to the inner side of the concha,
+it contributes to the movement of rotation by which the opening of the
+pinna of the ear is directed forwards.
+
+=Cervico-auricular Muscles= (Fig. 92, 13).--These muscles, three in
+number, are situated behind the pinna of the ear; they are called, from
+their mode of superposition, the superficial, middle, and deep.
+
+These arise, all three, from the superior cervical ligament, and pass
+from there towards the cartilage of the concha. They recall, as regards
+situation, the posterior auricular muscle of man.
+
+=Superficial Cervico-auricular= (_Cervico-auricularis
+superioris_).--This muscle, inserted into the posterior surface of the
+concha, draws this cartilage backwards and downwards.
+
+=Middle Cervico-auricular= (_Cervico-auricularis medius_).--Situated
+between the two other muscles of the same group, it proceeds, after
+having covered the superior extremity of the parotid gland, to be
+inserted into the external part of the base of the concha. It determines
+the rotation of this concha in such a way as to direct the opening of
+the ear backwards.
+
+=Deep Cervico-auricular= (_Cervico-auricularis inferioris_).--Covered by
+the preceding muscle and the superior portion of the parotid, it is
+inserted into the base of the pinna of the ear, and has the same action
+as the middle cervico-auricular.
+
+=Parotido-auricularis= (Fig. 92, 15).--This is a long and thin fleshy
+band which arises from the external surface of the parotid gland, and
+tapering as it passes upwards towards the pinna of the ear, is inserted
+into the external surface of the base of the concha, below the inferior
+part of the angle of reunion of the two borders which limit its opening.
+
+It inclines the pinna outwards; it is, accordingly, an abductor of the
+pinna.
+
+=Temporo-auricularis Internus.=--This muscle is covered by the external
+temporo-auricular and the superior cervico-auricular. It arises from the
+parietal crest, and is inserted into the internal surface of the concha.
+It is an adductor of the pinna of the ear.
+
+There are, finally, an internal scuto-auricular muscle and a
+tympano-auricular; but they do not present any interest for us; we can
+simply confine ourselves to making mention of them.
+
+In the ox, because of the situation of the temporal fossa and the fact
+that the external temporo-auricular muscle is applied, as in the horse,
+over the muscle which this fossa contains, this temporo-auricular muscle
+does not reach the middle line (Fig. 91, 12).
+
+But in the cat and the dog this muscle covers all the upper part of the
+head (Fig. 90, 12). It is divided into two parts: the interscutellar and
+the fronto-scutellar.
+
+The interscutellar is a single muscle, thin and broad, covering the
+temporal muscle and a portion of the occipital, extending from the
+scutiform cartilage of the pinna of one side to the same cartilage of
+the pinna belonging to the side opposite. It approximates the two pinnæ
+to one another by bringing them each into the position of adduction.
+
+The fronto-scutellar arises from the orbital process of the frontal
+bone, and from the orbital ligament, which at this level completes the
+interrupted osseous boundary of the orbital cavity. Thence it is
+directed, widening as it proceeds, towards the scutiform cartilage, and
+is there inserted by blending with the corresponding part of the great
+zygomatic. Its action is analogous to that of the preceding muscle; but,
+further, it directs the opening of the pinna forwards.
+
+These are the muscles which act, for example, when the dog, having his
+attention strongly attracted by any cause, pricks up his ears and turns
+the openings forward, in order the better to understand every sound
+which proceeds, or may possibly proceed, from that which he observes.
+From this, which may be extremely well seen in some individuals, results
+the appearance of vertical wrinkles of the skin in the interval between
+the pinnæ of the ears, these being caused by the folding of the
+integument, whilst the pinnæ approach one another. These movements, with
+which are associated fixation of look and a widening of the palpebral
+fissure, produce a peculiarly expressive look; this is why they merit
+our attention.
+
+=Zygomatico-auricularis= (Fig. 90, 11).--Arises from the internal
+surface of the great zygomatic, passes towards the pinna of the ear, and
+goes to be inserted into the external part of the base of the pinna,
+below its opening, to a prominence which corresponds to the antitragus
+of the human ear. It is to this antitragus, but proceeding from another
+direction, that the parotido-auricular muscle is inserted (Fig. 90, 15).
+
+With regard to the cervico-auriculars, they are all three present. The
+superior, or superficial, situated behind the interscutellar portion of
+the external temporo-auricular, has its origin on the median line of the
+neck; thence it passes towards the pinna of the ear, blending its fibres
+with those of the interscutellar muscle, and is inserted into the
+scutiform cartilage and the internal surface of the pinna.
+
+Such are the principal muscles of the ear in the carnivora; it would
+seem to us superfluous to dwell on the others of this region, so that we
+will here conclude the study of the muscles in general, and that of the
+myology of the head in particular.
+
+
+
+
+CHAPTER III
+
+EPIDERMIC PRODUCTS OF THE TERMINAL EXTREMITIES OF THE FORE AND HIND
+LIMBS
+
+
+We will first recall to mind that among the quadrupeds some are found of
+which the fingers and toes have their third phalanges terminated by
+claws--these are the unguiculates; and that in others the terminal
+extremity of each limb is completely encased in a horny envelope, the
+hoof--these are the ungulates.
+
+In the first group, the claws remind us to a certain extent of the
+arrangement of the nails in man; the inferior aspect of the paws is
+covered by an epidermic layer, thick and protective, which may be
+likened to the skin, correspondingly thick, which covers in the greater
+part of its extent the plantar surface of the foot in the human species.
+
+In the second group, the surface by which the third phalanx rests on the
+ground is correspondingly protected, but this time by a layer of horn
+which belongs to the hoof.
+
+After the preceding remarks, our study will be found to fall into a
+natural division, and it is in the order which we have just followed for
+the purpose of indicating its existence that we now proceed to study the
+nature and form of the different elements which complete or protect the
+digital extremities of the thoracic and abdominal limbs.
+
+=Claws.=--These horny coverings of the third phalanges, which we have to
+consider only in the dog and cat, may be compared with the nails of man,
+with which, however, they present, as is well understood, characteristic
+differences.
+
+The claws are compressed laterally, curved on themselves, and are
+terminated in front by a sharp point in the felide, but more blunted in
+the dog. Their superior border is convex and thick. We may say,
+therefore, that a claw is a sort of hollow tube, in the form of a cone
+flattened in the transverse direction, in which the third phalanx is
+set, and which is itself set in a groove formed by a kind of osseous
+hood which occupies the base of this third phalanx (see Fig. 37, p. 57).
+
+This definition is exact, as regards the general appearance; but, when
+more closely scrutinized, it is not sufficient. The tube in question is
+not formed of a single piece; each of the claws is formed by a lamina
+laterally folded, but of which the borders are not exactly joined
+together inferiorly; they leave between them a small interval, and this
+is filled by a layer of more friable horny substance, to which has been
+given the name of plantar nail. This arrangement, which is clearly
+defined in the dog (Fig. 93), is comparable to that which we shall
+afterwards meet with in connection with the sole of the hoof of the
+horse (see Fig. 100, p. 257). In the dog and the cat, the weight of the
+limb resting on the inferior surface of the phalanges, it was necessary
+that the region of the plantar surface of the foot corresponding to
+these latter should be protected; this is the function of certain
+fibro-adipose pads, which are situated there, and which are designated
+by the name of _plantar tubercles_.
+
+=Plantar Tubercles= (Fig. 94).--These tubercles, or dermic cushions, are
+divided, in each paw, into _tubercles of the digits_ (or of the toes), a
+_plantar tubercle_, and, on the fore-limbs, a _tubercle of the carpus_.
+
+The tubercles of the fingers (or of the toes) are of the same number as
+the latter. That which belongs to the thumb is but little developed, but
+the others are more so. They are in relation with the plantar surfaces
+of the second and third phalanges, so that when the paw is in contact
+with the ground the articulation which, in each of the fingers or toes,
+joins these phalanges, rests on the corresponding pad.
+
+The plantar tubercle is larger than the preceding. It is of a more or
+less rounded form; sometimes it is triangular, and then comparable in
+outline to the ace of hearts, the point of which is, in this case,
+turned towards the claws; its margin being sometimes strongly indented,
+it may also have a trilobate form. It is on it that rest the
+metacarpo-phalangeal or metatarso-phalangeal articulations, according to
+the limb studied. The tubercle of the carpus, situated at the level of
+the posterior surface of this latter, is less important than the
+preceding, the region which it occupies not reaching the ground during
+walking. But it is not to be neglected from the point of view of
+external form, because of the prominence which it produces.
+
+[Illustration: FIG. 93.--CLAW OF THE DOG: INFERIOR SURFACE.
+
+1, Horny lamina of the claw; 2, plantar nail; 3, tubercle of the
+corresponding digit.]
+
+[Illustration: FIG. 94.--LEFT HAND OF THE DOG: INFERIOR SURFACE, PLANTAR
+TUBERCLES.
+
+1, 1, 1, 1, 1, Tubercles of the fingers; 2, plantar tubercle; 3,
+tubercle of the carpus.]
+
+In the ungulates the terminal extremity of the limb is, as we have above
+pointed out, enclosed in a horny envelope which is no other than the
+hoof.
+
+We will first study the hoof of the horse--a hoof which is single for
+each of the limbs, inasmuch as in this animal each of these has but a
+single digit.
+
+=Hoofs of the Solipeds.=--We will first study the hoof as regarded in a
+general way--that is, without taking into account the limb to which it
+belongs. We will afterwards point out the differences presented when the
+hoofs of the fore and hind limbs are compared.
+
+In connection with the external forms of the horse, the study which we
+are now commencing is of great importance. But, before entering upon it,
+it appears to us necessary to rapidly examine what the hoof contains
+(Fig. 95).
+
+[Illustration: FIG. 95.--VERTICAL ANTERO-POSTERIOR SECTION OF THE FOOT
+OF A HORSE.
+
+1, Third phalanx; 2, fibro-cartilage; 3, podophyllous tissue; 4,
+inferior part of the wall; 5, section of the wall of the hoof; 6,
+cutigerous cavity; 7, tendon of the anterior extensor of the phalanges;
+8, reinforcing band coming from the suspensory ligament of the fetlock;
+9, tendon of the superficial flexor of the phalanges; 10, tendon of the
+deep flexor of the phalanges.]
+
+In the interior of this horny box we find the third phalanx, a small
+sesamoid bone placed opposite to the posterior border of the latter, a
+portion of the inferior extremity of the second phalanx, and the
+tendons, which terminate at this region.
+
+To the third phalanx are added two fibro-cartilaginous plates, flattened
+laterally, which prolong backwards the bone to which they are annexed.
+The inferior border of each of these fibro-cartilages is fixed by its
+anterior part to two osseous prominences situated at each of the angles
+which terminate the small phalanx behind; these prominences are: _the
+basilar process_ and _the retrorsal process_ (Fig. 96); by its posterior
+part, this border is continuous with a structure known as _the plantar
+cushion_ (see further on).
+
+The posterior border is directed obliquely upwards and forwards. The
+superior border, which is convex or rectilinear, is thin, and is
+separated from the posterior border by an obtuse angle. Finally, the
+anterior border, which is directed obliquely downwards and backwards, is
+united to the ligamentous apparatus, which keeps the second and third
+phalanges in contact.
+
+These fibro-cartilages, at their upper extremities, project beyond the
+hoof, and therefore assist in the formation of the lateral regions of
+the foot,[35] at the part which is called the _crown_. They project less
+above the hoof in the posterior limbs.
+
+  [35] Here, for the first time, apropos of the hoof, we use the word
+       'foot.' As in osteology and in myology we have, for the sake of
+       clearness of comparison, designated under this name the region
+       limited above by the tarsus, it is necessary to point out here
+       that we employ the same word for a more restricted region. This
+       we did in conformity with the usage of veterinarians, who so
+       designate the region of the hoof. It is necessary to explain this
+       double employment of the word, and, further, to show the
+       particular meaning ascribed to it.
+
+[Illustration: FIG. 96.--THIRD PHALANX OF THE HORSE: LEFT ANTERIOR LIMB,
+EXTERNAL SURFACE.
+
+1, Pyramidal eminence; 2, surface, for articulation with the inferior
+extremity of the second phalanx; 3, basilar process; 4, retrorsal
+process.]
+
+The posterior and inferior borders of these cartilages meet at an acute
+angle. The angle so formed, or cartilaginous bulb, constitutes the base
+of the region, which is commonly called the _heel_--a part of the foot
+which, as its name implies, is situated posteriorly, but which we must
+not confound, as we might be led to do, with the region occupied by the
+calcaneum. We know from our previous studies of comparative osteology
+that this latter is situated much higher up.
+
+The _plantar cushion_ is a sort of fibrous wedge which occupies the
+interval bounded by the fibro-cartilaginous plates which we have just
+been studying. Its inferior surface, the form of which we shall find to
+be reproduced by a portion of the corresponding surface of the hoof, is
+prolonged anteriorly into a point, while behind it is divided into two
+branches, which, diverging from one another, join the posterior angles
+of the fibro-cartilages. These two branches are separated by a median
+excavation.
+
+The different constituent elements which we have just been discussing
+give elasticity to the foot.
+
+To finish the examination of the parts contained in the hoof, we will
+add that among them is also found what is called the fleshy _envelope_,
+or _flesh_ of the foot.
+
+We divide the latter into three regions: the podophyllous tissue,
+striated or laminated flesh which is spread out over the anterior
+surface of the third phalanx; the pad, or the hardened skin which
+corresponds to the upper border of the hoof, and forms a prominence
+above the podophyllous tissue; and the villous flesh, or velvety tissue
+which covers the plantar surface of the third phalanx and the plantar
+cushion. These three tissues form as a whole the keratogenic
+membrane--that is to say, that which produces horny tissue, and
+consequently regenerates the hoof.
+
+It is this latter that we now proceed to study.
+
+When we examine its anterior surface or the opposite one, the hoof of
+the horse has the shape of a truncated cone with the base below and the
+summit cut off obliquely downwards and backwards (Fig. 97).
+
+Viewed on one of its lateral aspects, it may be compared to a truncated
+cylinder placed on the surface of the section (Fig. 98). We particularly
+call attention to this latter comparison, for it singularly aids us in
+making a representation of the foot of the horse when viewed laterally.
+
+Notwithstanding that the hoof forms apparently a homogeneous whole, it
+consists of three parts, which may be separated from one another by
+maceration. The indication of such disunion, artificially produced, may
+seem useless. It is not so, however, for this division of the hoof will
+permit us to carry out the study of the latter in a clearer, and
+consequently a more satisfactory, way. The three parts in question are
+the _wall_, or _crust_, the _sole_, and the _frog_.
+
+The _wall_ is that portion of the hoof which we see when the foot rests
+on the ground. It is a plate of horn which, applied to the anterior and
+lateral surfaces of the foot, diminishes in height as it approaches the
+posterior part of the region. Posteriorly and at each side the wall is
+folded on itself, and is then directed forwards to terminate in a point,
+after having enclosed the frog, which we will soon study.
+
+[Illustration: FIG. 97.--LEFT ANTERIOR FOOT OF THE HORSE: ANTERIOR
+ASPECT.
+
+1, Outer side; 2, inner side.]
+
+Although the wall forms a continuous whole, it has been divided into
+regions to which special names are given. The anterior part, from the
+superior border to the inferior, is called the _pince_ or _toe_ for a
+width of 4 to 5 centimetres. External to the toe, and on each side of
+it, for a distance of 3 or 4 centimetres, is the _nipple_. Behind the
+_nipples_ are the _quarters_. Still further back, where the wall folds
+on itself, forming the _buttress_, is found the region of the _heels_.
+Finally, the portions of the wall which form its continuation in passing
+forward are called the _bars_.[36] These are only visible on the
+inferior surface of the hoof (see Fig. 100).
+
+  [36] It is to the angle of inflexion or heel that some authors give
+       the name of buttress; it is the bars which other authors
+       designate in this fashion.
+
+The wall, convex transversely, is, in its anterior part (viz., the
+_toe_) inclined strongly downwards and forwards. This obliquity tends to
+become gradually effaced on the lateral parts to such a degree that at
+the quarters it becomes almost perpendicular to the surface of the
+ground.
+
+The internal quarter is less rounded than the external; in addition to
+this (Fig. 97), it approaches more nearly to the vertical direction.
+
+[Illustration: FIG. 98.--LEFT ANTERIOR FOOT OF THE HORSE: EXTERNAL
+ASPECT.
+
+1, Fetlock; 2, spur or beard; 3, pastern; 4, outline determined by the
+external fibro-cartilage; 5, acute angle; 6, nipple; 7, quarter; 8,
+heel.]
+
+In our opinion, this latter difference clearly recalls certain
+characters of the general form of the human foot. In fact, the latter
+has its dorsal surface inclined downwards and outwards, whereas its
+internal border may be said rather to be vertical. A transverse section
+of the foot (Fig. 99) justifies this comparison, which to us appears
+interesting, not only as regards the resemblance which exists between
+these organs of support, but, further, because it constitutes a mnemonic
+which enables us, on condition that we remember the form of the human
+foot, to recall the above-described character of that of the horse.
+
+The greater convexity of the outer portion of the hoof is found equally
+on the human foot; the external border of this foot is more convex than
+the opposite one.
+
+The inferior border of the wall (Fig. 100) is, in the case of unshod
+horses, always in wear when in contact with the ground. It is intimately
+united to the circumference of the sole (see further on).
+
+[Illustration: FIG. 99.--VERTICAL AND TRANSVERSE SECTION OF A LEFT HUMAN
+FOOT: OUTLINE OF THE DIVIDED SURFACE OF THE POSTERIOR SEGMENT OF THIS
+SECTION (DIAGRAMMATIC FIGURE).
+
+AA´, Vertical axis passing through the middle of the leg and the second
+toe; 1, outer side; 2, inner side.]
+
+The superior border is hollowed on its internal surface by a groove, the
+cutigerous cavity or basil, which lodges the cushion (see Fig. 95). We
+have described this latter above, in connection with the flesh of the
+foot.
+
+The substance of the wall presents a fibrous appearance which is pretty
+strongly pronounced. The constituent fibres from which this appearance
+results are directed from the superior border towards the inferior in
+parallel and regular lines.
+
+The _sole_ is a horny plate which occupies the inferior surface of the
+hoof (Fig. 100). It is situated between the inferior border of the wall
+and the bars; and, on account of the oblique direction of these latter,
+it presents a strongly-marked groove of a [V]-form, with the opening
+directed backwards. In this depression is lodged the frog.
+
+The inferior surface is concave, and thus forms a sort of vault, more or
+less deep, according to the individual. The sole has a scaly, laminated
+aspect.
+
+We have seen (Fig. 93, and p. 249) that on the inferior surface of the
+claws of carnivora is found a small interval which is filled by a plate
+of a more friable horny substance, to which has been given the name of
+the plantar nail. It seems to us that there is an interesting
+relationship between the said plantar nail and the sole which we have
+just been studying.
+
+[Illustration: FIG. 100.--INFERIOR SURFACE OF A FORE-HOOF OF THE HORSE:
+LEFT SIDE.
+
+1, Internal border of the wall (toe); 2, wall; 3, quarter; 4, heel; 5,
+bar; 6, sole; 7, frog; 8, median cavity; 9, prominence of the frog; 10,
+lateral cavity.]
+
+Indeed, these two horny structures appear to be homologous. Is not the
+lamina of the claw comparable to the wall of the hoof? And does not the
+interval which occurs at the inferior part of this latter, and is filled
+by the sole, recall that which, in extremely reduced form, is filled by
+the plantar portion of the claws?
+
+The _frog_ (Fig. 100) is a mass of horn, in form of a wedge, with its
+apex in front, which occupies the space limited laterally by the
+recurved portions of the wall (the bars) and the posterior border of the
+sole.
+
+It covers the plantar cushion previously described (p. 252) and
+reproduces its form.
+
+Its inferior surface is hollowed out in the middle by an excavation,
+which is known as the _median lacuna_. This cavity separates the
+branches of the frog, which terminate posteriorly by two swellings which
+are known as _the prominences of the frog_, forming two rounded
+elevations situated above the claws. These same branches unite in front
+of the median lacuna to form the body of the frog. This latter, in its
+anterior part, gradually narrows, and terminates in a point which
+occupies the bottom of the hollow limited laterally by the bars of the
+wall and the posterior border of the sole.
+
+Between the lateral surfaces of the frog and the bars are found two
+angular cavities--_the lateral lacunæ_, or the _commissures of the
+frog_.
+
+[Illustration: FIG. 101.--THIRD PHALANX OF THE HORSE: LEFT ANTERIOR
+LIMB, INFERIOR VIEW.
+
+1, External border; 2, internal border; 3, semilunar crest; 4, 4,
+re-entrant processes.]
+
+[Illustration: FIG. 102.--THIRD PHALANX OF THE HORSE: LEFT POSTERIOR
+LIMB, INFERIOR VIEW.
+
+1, External border; 2, internal border; 3, semilunar crest; 4, 4,
+re-entrant processes.]
+
+As an indispensable complement to the study which we have just
+made, it is necessary to add that the hoofs of the fore-limbs and
+those of the hind ones present differences of form which cannot be
+ignored--differences which we are already able to conjecture by looking
+at the respective third phalanges which terminate those limbs, and
+especially at their inferior surfaces (Figs. 101, 102).
+
+The hoofs of the fore-limbs (see Fig. 100), viewed on their plantar
+surface, are more rounded than those of the hind-limbs (Fig. 103)--so
+that their external contour may be compared to a semicircle--whilst the
+hind-hoofs, which are narrow and of more oval shape, rather recall by
+their form the aspect of an ogive.
+
+This seems to result from the fact that the fore-limbs support the more
+considerable part of the weight of the animal. The best proof which can
+be given of this overweighting is the eagerness with which very often,
+when a horse is stopped near the edge of a footpath, for example, he
+places his fore-feet on the latter. In thus raising his fore-quarters,
+he throws part of his weight backwards, and in this way relieves his
+fore-limbs.
+
+[Illustration: FIG. 103.--INFERIOR SURFACE OF A HIND-HOOF OF A HORSE:
+LEFT SIDE.
+
+1, External border; 2, internal border.]
+
+With regard to the difference of form which we have just pointed out, we
+have sometimes heard the following comparison made: the contour of the
+hoofs of the fore-limbs, viewed from below, recalls that of an apple;
+that of the hoofs of the hind-limbs recalls the outline of a pear.
+
+As a mnemonic this comparison is insufficient, for nothing connects
+either of the forms indicated with the region to which the hoofs belong.
+
+We much prefer one made for us this very year by one of the students of
+our course at the School of Fine Arts, after the lecture in which we had
+just pointed out the differences in question. Giving the idea of a
+semicircle and an ogive, which we described above, he remarked to us
+that the idea would perhaps be more easily fixed in the memory if we
+associated with it the idea of the chronological order in which the
+Roman and ogival art succeeded. Indeed, as the Roman art preceded the
+ogival art, so the hoofs which have the semicircular form precede those
+which have the form of an ogive.
+
+This interpretation appeared to us ingenious; this is why we wished to
+give it here a place which seems to us to be merited.
+
+[Illustration: FIG. 104.--LEFT POSTERIOR FOOT OF A HORSE: EXTERNAL
+ASPECT.]
+
+The wall of the hoof of a fore-limb, viewed on one of its lateral
+surfaces (see Fig. 98), is more oblique than that of one of the
+hind-hoofs looked at in the same way (Fig. 104). This difference, very
+marked especially at the region of the toe, is correlated with that of
+the direction of the pastern. In fact, in the anterior limbs this is a
+little more oblique than in the opposite ones.
+
+We have still to describe, in connection with the horse, some epidermic
+tissues, which are known as _chestnuts_.
+
+The chestnut is a small, horny plate which is found on the internal
+surface of each of the limbs, at a level differing on the anterior from
+that of the posterior ones.
+
+On the anterior limbs the chestnut is situated on the internal surface
+of the forearm, towards the middle part, or the inferior third of this
+region. On the posterior limbs it is developed on the back of the
+superior extremity of the internal surface of the canon, towards the
+inferior part of the ham--that is, the tarsus.
+
+[Illustration: FIG. 105.--FOOT OF THE OX: LEFT SIDE, ANTERO-EXTERNAL
+VIEW.
+
+1, Internal hoof; 2, external hoof; 3, internal surface of this latter;
+4, internal spur.]
+
+Inasmuch as some authors consider the chestnuts as being vestiges of the
+thumb and the great-toe, we propose giving a mnemonic which will enable
+us to remember their situation, or, rather, their difference of level.
+
+If we consider that the thumb, in the human species, is longer than the
+first toe, we may easily remember that the chestnut is placed higher in
+the anterior limbs than in the posterior ones. Indeed, if we suppose a
+digit taking its origin at these points, it will be longer in front (the
+thumb) than behind (the first toe).
+
+=Hoofs of the Ox and the Pig.=--The ox has four hoofs on each foot--two
+which contain the third phalanges, and two others, rudimentary, situated
+at the posterior aspect of the limb, at the level of the inferior part
+of the canon; these latter bear the name of _spurs_. We will occupy
+ourselves especially with the former (Fig. 105).
+
+Each of the hoofs presents three faces which, if we consider them in
+relation to the median axis of the limb to which they belong, are:
+external, internal, and inferior. The external surface resembles the
+wall of the hoof of the horse. The internal surface is slightly concave
+from before backwards, so that the external and internal hoofs of the
+same foot are not in contact with each other, except by the extremities
+of this surface, and that an interval separates them between these two
+points. The inferior surface, slightly depressed, ends behind in a
+swelling produced by the plantar cushion, which covers a thin lamina of
+horn.
+
+At the anterior part of the hoof these three surfaces unite in forming a
+well-marked angle which, on account of the concavity of the internal
+surface, is slightly curved towards the axis of the foot.
+
+The pig has also four hoofs--two for the great digits and two for the
+lateral digits. They recall those of the ox.
+
+
+
+
+CHAPTER IV
+
+PROPORTIONS
+
+
+Inasmuch as we have taken for granted, in connection with the present
+volume, that before entering on the study of the anatomy of quadrupeds
+the reader was prepared for it by a sufficient knowledge of human
+anatomy, it is quite natural that we should extend the same supposition
+to the study of proportions.
+
+For this reason, the definition of proportions, considered from a
+general point of view, their signification, their function and their
+utility, are questions which it would be superfluous to enter upon here.
+We will content ourselves by calling to mind that the common measure
+chosen by preference is the length of the head, and that, ordinarily, it
+is with it that we compare the dimensions of other parts.
+
+Among the animals whose structure we have examined, there is one of
+which the proportions deserve to be marked in preference to every other:
+this is the horse.
+
+Wherefore this preference? In the first place, it is because of the
+overwhelming position which this animal occupies in the artistic
+representation of quadrupeds; that it is more frequently associated with
+man; that, notwithstanding its division into different races, its
+general proportions may be referred to a special type.
+
+It is also because the indications relative to these proportions will
+suffice to show the way which the artist must follow in order to find
+for himself, at the time when the necessity for it arises, the
+proportions which characterize the other animals.
+
+Our intention is not, in connection with the subject which now occupies
+us, to enter into a deep discussion on the various opinions which have
+been set forth. We desire, above all, to give some indications which,
+from the practical point of view, can be utilized in the representation
+of the horse, and at the beginning to demonstrate the advantages of
+these indications. Now, there is a fact which we have had occasion to
+note; it is the following: almost invariably, when a person who is
+little accustomed to represent the horse, or not previously informed of
+certain proportions of lengths, begins to draw from nature, the error
+generally committed is that of making the head too small and the body
+too long. Is it a preconceived idea which is the cause that one regards
+them in this manner? Perhaps. At all events, certain artists who have
+made the representation of horses their special study have even had this
+habit. It is therefore necessary to be informed of the proportions; this
+is the object of the study which we are now undertaking.
+
+Bourgelat,[37] in the eighteenth century, fixed for the first time and
+in complete fashion the proportions of the horse; it is he,
+consequently, who created the æsthetics of the horse. It is but justice
+to recall the fact. His system has a point of analogy with that which is
+employed to determine the human proportions. Indeed, Bourgelat chose the
+length of the head as a standard of measurement, and the subdivisions of
+the head for measures of less extent. 'Since beauty,' said he,[38]
+'resides in the congruity and proportion of the parts, it is absolutely
+necessary to observe the dimensions, individual and relative, and in
+order to acquire a knowledge of the proportions, to assume a kind of
+measure which can be indiscriminately common for all horses. The part
+which can serve as a standard of proportion for all the others is the
+head. Take a measurement between two parallel lines--one tangent to the
+nape of the neck or the summit of the forelock, the other tangent to
+the extremity of the anterior lip--a line perpendicular to these two
+tangents will give you its geometrical length. Divide this length into
+three portions, and give to these three parts a special name, which may
+be applied indefinitely to all heads--as, for example, that of _prime_.
+Any head whatsoever will, accordingly, in its geometrical length, always
+have three _primes_; but all the parts which you will have to consider,
+whether in their length, in their height, or in their width, cannot
+constantly have either one prime, or a prime and a half, or three
+primes; subdivide, then, each _prime_ into three equal parts, which you
+will name _seconds_, and as this subdivision will not suffice to give
+you a just measure of all the parts, subdivide anew each _second_ into
+twenty-four _points_, so that a head divided into three _primes_ will
+have, by the second division, nine _seconds_, and two hundred and
+sixteen _points_ by the last.'
+
+  [37] Claude Bourgelat, founder of the veterinary schools in France. He
+       was born at Lyons in 1712, and died at Paris in 1779.
+
+  [38] Bourgelat, 'Éléments de l'art vétérinaire. Traité de la
+       conformation extérieure du cheval,' Paris, edition of 1785, p.
+       133.
+
+But where this system appears to us to have lost somewhat of its unity
+is when the author transforms it, in pointing out the following mode of
+procedure: 'But the head itself may err by default of proportion. This
+part is not, indeed, considered as either too short or too long, too
+thin or too thick, but by comparison with the body of the animal. Now,
+the body, being required to have--whether in length, reckoning from the
+point of the arm to the prominence of the buttock, or in height,
+reckoning from the summit of the withers to the ground--two heads and a
+half; whenever the head, by its geometrical length, shall give, in
+length or in height, to the body measured more than two and a half times
+its own length, it will be too short; and if it gives less, it will be
+too long.
+
+'In the case in which one of these faults exists there would be no
+further question of establishing by its geometrical length the
+proportions of the other parts. Give up this common measure, and measure
+the height or the length of the body; divide the length or the height
+into five equal portions; take, then, two of these divisions, divide
+them into _primes_, _seconds_, and _points_, corresponding to the
+divisions and subdivisions which you would have made of the head, and
+you will have a common measure, such as the head would have given you if
+it had been proportionate.'[39]
+
+  [39] Bourgelat, _loc. cit._, p. 135.
+
+[Illustration: FIG. 106.--THE PROPORTIONS OF THE HORSE (AFTER
+BOURGELAT).
+
+_To face p. 265._]
+
+We understand, up to a certain point, that Bourgelat may have been able
+to give this advice which, generally speaking, is sufficiently
+practical, since, in certain cases, he was able to pronounce that such a
+head was too small or too large. But it is always mischievous, with
+regard to the effect produced on the reader, to propose to him, in the
+application of a rule, to suppress the foundation on which this rule is
+established. Besides, even if all the measurements compared with the
+two-fifths of the length of the body are proportionate with regard to
+one another, the animal, in spite of this, since the head must be taken
+into consideration, will, in a strict sense, be none the less
+disproportioned.
+
+The proportions given by Bourgelat are as follows[40] (Fig. 106):
+
+  [40] _Ibid._, p. 136, and onward.
+
+1. =Three geometrical lengths of the head= give:
+
+_The full height_ of the horse, reckoned from the forelock to the ground
+on which he rests, provided that the head be well placed.[41]
+
+  [41] By 'the head being well placed,' Bourgelat means 'vertically
+       posed,' the outline of the forehead then coinciding with a
+       vertical line, which at the other end touches the anterior
+       portion of the nose.
+
+2. =Two heads and a half= (B)[42] equals:
+
+  [42] The letters in parentheses relate to the corresponding measures
+       marked by the same letters on the third diagram of Fig. 106.
+
+_The height of the body_ from the summit of the withers to the ground.
+
+_The length of the same body_, those of the forehand and of the
+hind-quarter taken as a whole from the point of the arm to the point of
+the buttock inclusive.
+
+3. =An entire head= (A) gives:
+
+_The length of the forepart_ from the summit of the withers to the
+termination of the neck.
+
+_The height of the shoulders_ from the summit of the elbow to the top of
+the withers.
+
+_The thickness of the body_ from the middle of the belly to the middle
+of the back.
+
+_The width_ from one side to the other.
+
+4. =A head measured from the top of the forelock to the commissure of
+the lips= (C). This measurement slightly curtailed, unless the mouth is
+very deeply cleft, equals:
+
+_The length of the crupper_, taken from the superior point of the
+anterior angle of the ilium to the tuberosity of the ischium, forming
+the point of the buttock.
+
+_The width of the crupper or of the haunches_, taken from the inferior
+points of the angles of the ilia.
+
+_The height of the crupper_, viewed laterally, taken from the summit of
+the posterior angles of the ilia to the point of the patella, the leg
+being in a state of rest.
+
+_The lateral measure of the posterior limb_, from the point of the
+patella, to the lateral and salient part of the ham, to the right of the
+articulation of the tibia with the trochlea.
+
+_The perpendicular height of the articulation above named_ above the
+ground.
+
+_The distance from the point of the arm_ to the angle formed by the
+junction of the head and neck.
+
+_The distance from the summit of the withers_ to the junction of the
+neck with the thorax.
+
+5. =Twice this last measure= (C)[43] gives almost:
+
+  [43] The proportions given in the two paragraphs 6 and 7 are, under
+       another form, the same as those pointed out in paragraph 2, with
+       this difference, that in this latter they are more clearly
+       expressed.
+
+_The distance of the summit of the withers_ to the tip of the patella.
+
+_The distance of the point of the elbow_ to the summit of the crupper or
+the posterior angles of the ilia.
+
+6. =Three times this measure, plus a half-width of the pastern, the
+equivalent of two heads and a half=, will give:
+
+_The height of the body_, taken from the top of the withers to the
+ground.
+
+_Its length_, taken from the point of the arm to the point of the
+buttock inclusive.
+
+7. =This same measure, plus the entire width of the pastern=, gives:
+
+_The total length of the body_, taken accurately.
+
+8. =Two-thirds the length of the head= (D) will equal:
+
+_The width of the chest_, from the tip of one arm to that of the other,
+from outside to outside.
+
+_The horizontal measurement of the crupper_ taken between two verticals,
+of which one forms a tangent to the buttock, and the other passes
+through the summit of the crupper and touches the tip of the patella.
+
+_The third of the length of the hind-quarter and of the body_ taken
+together, as far as the vertical from the withers, touching the elbow.
+
+_The anterior length of the hind-limb_, taken from the tuberosity of the
+tibia to the fold of the ham.
+
+9. =One-half of the length of the head= (E) is the same as:
+
+_The horizontal distance from the tip of the arm_ to the vertical line
+from the summit of the withers and touching the elbow.
+
+_The width of the neck_, viewed laterally, taken from its insertion in
+the trough of the jaw to the roots of the first hairs of the mane, on a
+line which forms with the superior contour two equal angles.
+
+10. =One-third of the entire length of the head= (F) gives:
+
+_The height of its superior part_ from the summit of the forelock to a
+line which passes through the most salient points of the orbits.
+
+_The width of the head_ below the lower eyelids.
+
+_The lateral width of the forearm_, taken from its anterior origin to
+the point of the elbow.
+
+11. =Two-thirds of this length=[44] (G) gives:
+
+  [44] That is to say, two-ninths of the whole length of the head.
+
+_The distance of the point of the elbow_ above the plane of the lower
+surface of the sternum.
+
+_The depression of the back_ in relation to the summit of the withers.
+
+_The lateral width of the posterior limbs near the hams._
+
+_The space or distance of the forearms from one ars_[45] to the
+opposite.
+
+  [45] We call the region where the superior and internal part of the
+       forearm is joined to the trunk the 'ars.' The space between the
+       ars of one side and the ars of the opposite side is called the
+       'inter-ars.'
+
+12. =One-half of the third of the entire length of the head=[46] (H)
+equals:
+
+  [46] That is to say, one-sixth of the total length of the head.
+
+_The thickness of the forearm_, viewed from the front, and taken
+horizontally from the ars to its external surface.
+
+_The width of the crown of the fore-feet_ whether from one side to the
+other, or from before backwards.
+
+_The width of the crown of the hind-feet_, from one side to the other
+only.
+
+_The width of the posterior fetlocks_, taken from the front to the
+origin of the spur.
+
+_The width of the knee_ seen from the front. Note: this measure is a
+little too large.
+
+_The thickness of the ham._ Note: this measure is a little under the
+mark.
+
+13. =One-fourth of the third of the length of the head=[47] (I) gives:
+
+  [47] That is, one-twelfth of the length of the head.
+
+_The thickness of the canon of the fore-limb_: that of the hind-quarter
+is a little thicker.
+
+14. =One-third of this same measure=[48] (K) equals:
+
+  [48] That is, a ninth of the length of the head.
+
+_The thickness of the fore-limb close to the knee_ in its narrowest
+part.
+
+_The thickness of the posterior pasterns_, viewed laterally.
+
+15. =The height from the elbow to the fold of the knee= (L) is the same
+as:
+
+_The height from this same fold to the earth._
+
+_The height from the patella to the fold of the ham._
+
+_The height from the fold of the ham to the crown._
+
+16. =The sixth part of this measure= (M) gives:
+
+_The width of the canon of the fore-limb_, viewed laterally, in the
+middle of its length.
+
+_The fetlock_, viewed from the front.
+
+17. =The third of this same measure= (N) is very nearly equal to:
+
+_The width of the ham_, from the fold to the point.
+
+18. =A fourth of this measure= (O) gives:
+
+_The width of the knee_, measured laterally.
+
+_The length of the knee._
+
+19. =The interval between the eyes from one great angle to the other=
+(P) equals:
+
+_The width of the hind-leg_, viewed laterally, from the cleft of the
+buttocks to the inferior part of the tuberosity of the tibia.
+
+20. =One-half of this interval between the eyes= (1/2 P) gives:
+
+_The width of the posterior canon-bone_, viewed laterally.
+
+_The width of the fetlock of the fore-limb_, from its anterior summit to
+the root of the spur.
+
+Finally, the difference of the height of the crupper with respect to the
+summit of the withers.
+
+It is certain that the multiplicity of these proportions, and above all
+the exaggeration of details into which Bourgelat fell in indicating
+certain of the measures which constitute the bases of some of them, may
+repel the reader.
+
+For this cause we desire to add to the preceding, and also because the
+question which we are treating would be incomplete without it, the
+results obtained and published by other more modern authors, and in
+particular by Colonel Duhousset.[49]
+
+  [49] E. Duhousset, 'Le Cheval,' Paris, 1881.
+
+This author, one of whose constant occupations is the measurement of the
+different regions of the horse, has the incontestable merit of having
+drawn attention to this question, and of having strained all his
+energies in the propagation of the knowledge which until then was little
+diffused. Among the proportions which he recommends, there are some
+which are the result of his own observations; whilst others, which he
+has verified and adopted, are the result of a judicious selection of
+those given by Bourgelat, which we have just reproduced in the preceding
+pages.
+
+We join thereto also certain indications furnished by MM. A. Goubeaux
+and G. Barrier,[50] distinguishing these latter by the initials (G. and
+B.) of their authors (Fig. 107).
+
+  [50] Armand Goubeaux and Gustave Barrier, 'De l'extérieure du Cheval,'
+       Paris, 1882.
+
+=The length of the head almost exactly equals=:
+
+1. Depth from the back to the belly, N, O,[51] the thickness of the
+body.[52]
+
+  [51] Look for the points indicated by these letters on Fig. 107, which
+       is related to the proportions which are here discussed.
+
+  [52] The proportion previously indicated by Bourgelat (see p. 265,
+       paragraph 3).
+
+2. From the summit of the withers to the point of the arm, H, E.
+
+3. From the superior fold of the stifle to the point of the ham, J´, J.
+
+4. From the point of the ham to the ground, J, K.
+
+5. From the dorsal angle of the scapula to the point of the haunch, D,
+D.
+
+[Illustration: FIG. 107.--PROPORTIONS OF THE HORSE (AFTER COLONEL
+DUHOUSSET).]
+
+6. From the passage of the girth to the fetlock, M, I, or higher in
+large horses and racers; to the middle of the fetlock or lower for small
+ones and those of medium size.
+
+7. From the superior fold of the stifle to the summit of the crupper in
+those specimens whose coxo-femoral angle is very open. This distance is
+always much less in others (G. and B.).[53]
+
+  [53] A proportion relative to the same region, and which at the outset
+       might appear similar, is pointed out by Bourgelat (see p. 266,
+       paragraph 4). But there exists a difference, for Bourgelat
+       compared the length of the head, measured from the forelock to
+       the commissure of the lips, and not that of the entire head, to
+       the distance which separates the summit of the rump and the tip
+       of the patella.
+
+=Two and a half times the length of the head= gives:
+
+1. The height of the withers, H, above the ground.[54]
+
+  [54] This proportion is that given by Bourgelat (see p. 265, paragraph
+       2).
+
+2. The height of the summit of the crupper above the ground.[55]
+
+  [55] Consequently the withers and the crupper, being the same height,
+       are situated on the same horizontal plane. Bourgelat, on the
+       contrary, points out a difference of level in connection with
+       these regions. According to him the summit of the crupper is
+       situated below the horizontal plane passing the withers, and this
+       distance equals half of the space which separates the great angle
+       of one eye from that of the other (see p. 269, paragraph 20).
+
+3. Very often the length of the body, from the point of the arm to that
+of the buttock, although for a long time the type of Bourgelat had been
+set aside as a conventional model, short and massive.[56]
+
+  [56] See p. 265, paragraph 2.
+
+And M. Duhousset adds to this:
+
+'The drawing that we offer, which has two heads and a half in height and
+length, is that of a horse which we frequently meet with' (see Fig. 107;
+see also p. 279, where we again consider this question of the length of
+the body of the horse).
+
+'The crupper, from the point of the haunch to that of the buttock, D, F,
+is always less than that of the head. This difference varies from 5 to
+10 centimetres. The width of the crupper, from one haunch to the other,
+often very slightly exceeds its length.' MM. Goubeaux and Barrier add
+that frequently it equals it.[57]
+
+  [57] If we refer to the proportions indicated by Bourgelat, we shall
+       find that the proportions relative to the crupper are also
+       indicated there (see p. 266, paragraph 4).
+
+'The crupper, such as we have just defined it, D, H, may also be found
+to a fair degree of exactness, as regards length, four times on the same
+horse.'
+
+1. From the point of the buttock to the inferior part of the stifle, F,
+P.
+
+2. The width of the neck, a little in front of the withers to a little
+above the point of the arm, S, X.[58]
+
+  [58] MM. Goubeaux and Barrier replace this by the following: 'The
+       width of neck at its inferior attachment from its insertion into
+       the chest to the origin of the withers, S, X.' Bourgelat
+       discovered the same proportion (see p. 266, last line of
+       paragraph 4).
+
+3. From this latter point to below the lower jaw, X, Q, when the head is
+naturally placed parallel to the shoulders, E, H.[59]
+
+  [59] MM. Goubeaux and Barrier replace this by the following: 'From the
+       insertion of the neck into the chest to the lower border of the
+       lower jaw, X, Q, when the head is parallel to the shoulder.'
+
+4. From the nape to the nostrils, _n, n´_.[60]
+
+  [60] MM. Goubeaux and Barrier add: 'Or to the commissure of the lips.'
+       It is thus, besides, that Bourgelat measured the head for
+       comparison with the crupper (see p. 266, paragraph 4).
+
+The measure of =half of the head= also acts as a good guide for the
+construction of the horse, when we know that it frequently applies to
+many of the parts--to wit:
+
+1. From the forehead above the eyes, perpendicular to the line which is
+tangent to the lower jaw, P, Q.
+
+2. Outline of the neck at the level of the base of the head, Q, L.[61]
+
+  [61] Proportion indicated by Bourgelat (see p. 267, paragraph 9).
+
+3. From the crown of the fore-foot to below the knee, T, T´.
+
+4. In the legs, from the base of the fetlock to that of the ham, U, V.
+
+5. Finally, it is nearly of the length of the humerus from the point E
+to the radius.[62]
+
+  [62] MM. Goubeaux and Barrier replace these by the following:
+
+       1. 'From the most prominent part of the lower jaw to the profile
+       of the forehead above the eye, P, Q (thickness of the head).
+
+       2. 'From the throat to the superior border of the neck behind the
+       nape, Q, L (attachment of the head).
+
+       3. 'From the inferior part of the knee to the crown, T, T´.
+
+       4. 'From the base of the ham to the fetlock, U, V.
+
+       5. 'Finally, from the point of the arm to the articulation of the
+       elbow (approximate length of the arm).'
+
+
+PROPORTIONS OF THE HEAD OF THE HORSE[63]
+
+  [63] Extract from the work of MM. Goubeaux and Barrier on the exterior
+       of the horse. As before, the initials G. and B. of these authors
+       are added.
+
+Although it is very difficult, says M. Duhousset, when we speak of
+measurements taken on the living animal, to formulate other than
+approximations, we believe we have determined with sufficient accuracy
+the following results, which are the outcome of our numerous
+observations. The head which we present is that of a horse which we have
+frequently come across as a mean term between the highly bred and the
+draught horse. Under this heading, it will not be devoid of interest to
+accompany with dimensions the two drawings to which are consigned the
+measurements in question.
+
+=Head viewed in Profile= (Fig. 108).--Length, A, B, from the nape to the
+margin of the lips, 0·60 metre.
+
+Thickness, C, D, from the angle of the lower jaw to the anterior surface
+(a half-head), 0·30 metre. This line passes through the middle of the
+eye, taken perpendicularly, to the profile of the anterior surface. Many
+common horses present it, especially the heavier draught horses; in
+finely-bred subjects it is a little shorter (G. and B.).
+
+Depth, I, H, of the neck in its narrowest part (a half-head), 0·30
+metre. It is frequently greater; this is noticeable in all instances
+where the superior parts of the neck are deficient in fineness. It is
+this which we see in draught horses, and in those which become too
+fleshy (G. and B.).
+
+Distance, O, R, of the internal commissure of the eye from the superior
+border of the commissure of the nostril (G. and B.) (a half-head), 0·30
+metre. It is more considerable on the common head, and on that which is
+too long.
+
+Distance, A, O, from the nape to the internal angle of the eye, 0·22
+metre. This distance is equivalent to the thickness of the head, P, Q,
+taken perpendicularly from the profile of the anterior surface, and
+passing at the level of the maxillary fissure and spine.
+
+It is, again, equal to Q, O, from the internal angle of the eye to the
+maxillary fissure; and to P, G, from the middle of the face to the
+commissure of the lips (G. and B.).
+
+The distance, P, E, from the middle of the face to the maxillary spine
+is about the sixth of the total length of the head--0·10 metre.
+
+[Illustration: FIG. 108.--PROPORTIONS OF THE HEAD OF THE HORSE, VIEWED
+IN PROFILE (AFTER COLONEL DUHOUSSET).]
+
+The line B, E, reckoned from the extremity of the lips to the maxillary
+spine, is equal:
+
+To E, F, from the maxillary spine to the external auditory meatus, to be
+seen only on the skull;
+
+To H, G, from the insertion of the neck in the trough to the commissure
+of the lips (G. and B.);
+
+To Q, R, from the maxillary fissure to the superior commissure of the
+nostril (G. and B.);
+
+To Q, B, from the fissure of the maxilla to the border of the lips (G.
+and B.);
+
+To O, D, from the internal angle of the eye to the angle of the lower
+jaw, provided that the line C, D be in proportion (G. and B.).
+
+[Illustration: FIG. 109.--THE SAME DESIGN AS THAT OF FIG. 108, ON WHICH
+WE HAVE INDICATED, BY SIMILAR LINES, THE PRINCIPAL CORRESPONDING
+MEASUREMENTS.
+
+Half the length of the head, and the dimensions which equal it; distance
+which separate the nape from the internal angle of the eye, and the
+dimensions which equal it; distance which separates the internal angle
+of the eye from the border of the lips, and the dimensions which equal
+it.[64]]
+
+  [64] It is thus that in our teaching, but by means of lines of
+       different colours, we present the proportions reproduced in Fig.
+       108. Experience has demonstrated to us that this replacement of
+       letters by conventional lines renders the proportions more easily
+       appreciable, and that these lines, striking the eye more
+       forcibly, then impress themselves better on the memory. Fig. 111
+       bears the same relation to Fig. 110.
+
+Finally, very frequently to O, H, from the internal angle of the eye to
+the insertion of the throat into the maxillary trough (G. and B.).
+
+An equality still more frequent is that which exists between the
+distances:
+
+O, B, from the internal angle of the eye to the margin of the lips;
+
+A, H, from the nape to the insertion of the throat into the maxillary
+trough;
+
+And H, B, from this latter point to the margins of the lips.
+
+[Illustration: FIG. 110.--PROPORTIONS OF THE HEAD OF THE HORSE, SEEN
+FROM THE FRONT (AFTER COLONEL DUHOUSSET).]
+
+=The Head, Front View= (Fig. 110).--If, to continue our examination,
+adds M. Duhousset, we regard the head from the front, we find its
+greatest width at A, B, the extreme points of the orbital arches.
+
+This width is 22 centimetres.
+
+It is again equal to:
+
+A, C, from one arch to the nape;
+
+A, D, from one arch to the middle of the face.
+
+D, E, from the middle of the face to the margin of the lips.
+
+From the auditory canal, G, to the maxillary spine, F, is the same
+distance as from this point to the margins of the lips, E, or, better,
+to the end of the teeth.
+
+[Illustration: FIG. 111.--THE SAME FIGURE AS FIG. 110, ON WHICH WE HAVE
+MARKED BY SIMILAR LINES THE PRINCIPAL MEASUREMENTS WHICH CORRESPOND
+THERETO.
+
+Distance which separates one of the orbital arches from that of the
+opposite side, and the dimensions which equal it; distance which
+separates the auditory meatus from the maxillary spine, and the
+dimensions which equal it; distance which separates one maxillary spine
+from that of the opposite side, and the dimensions which equal it;
+distance which separates the lip of one side from that of the opposite,
+and the dimensions which equal it.[65]]
+
+  [65] See the note relative to Fig. 109.
+
+The line G, C, from the auditory meatus to the nape, is equal to the
+sixth of the head, 10 centimetres; the line A, G, from the orbital arch
+to the auditory meatus, is a little longer, and measures 12
+centimetres.
+
+The distance F, I, comprised between the maxillary spines, is 18
+centimetres.
+
+It is equal to:
+
+O, O, the distance between the internal angles of the eyes (G. and B.);
+
+F, R, the distance from the maxillary spine to the superior commissure
+of the corresponding nostril (G. and. B.);
+
+F, P, from the maxillary spine to the _salt-cellar_.[66]
+
+  [66] We designate under the name _salt-cellar_ a depression situated
+       external to the frontal region and above the eye.
+
+From the nape to the internal angle of the eye, C, O, is the same
+distance as from this latter point to the commissure of the lips, O, T;
+and from the maxillary spine to the upper lip F, S (G. and B.).
+
+The distance apart, T, T, of the two commissures of the lips gives, very
+nearly, the distance from the superior border of the orbital arch to the
+base of the ear or the auditory meatus. In the state of rest, the outer
+limit of the separation of the nostrils does not exceed the width of the
+knee;[67] we frequently find the same distance intercepted above the
+nape by the tranquil ears. In the figure (Fig. 110) we have
+intentionally represented them directed in a different plane, in order
+to show that when the pinna is turned backward, it none the less
+preserves the contour of bracket form, more or less pronounced according
+to the breeding of the subject, and characterizing in repose the
+interior curves of the ear.
+
+  [67] We remind our readers that the name 'knee' is given by
+       veterinarians to the region occupied by the carpus.
+
+The extreme limit of the lips, M, N, but very slightly exceeds that of
+the nostrils; on many heads of harmonious proportions this distance is
+found to be the half of A, B.
+
+In order not to interrupt the course of the preceding exposition, we
+decided to withhold till afterwards some reflections which have been
+suggested to us by certain of the proportions which are there indicated.
+The proportions in question are important--we may even say that they are
+fundamental, for they have for object the relation which exists between
+the length of the head, the height of the body, and the length of the
+latter.
+
+We have already seen that, according to Bourgelat, the length of the
+head is contained two and a half times in the length of the body, from
+the point of the arm to the point of the buttock; and, also, two and a
+half times in the height measured from the apex of the withers to the
+ground (see p. 265). We saw afterwards that M. Duhousset, having adopted
+these proportions, pointed out, further, that the same dimension was
+again found equally to exist from the summit of the crupper to the
+ground--a height which Bourgelat considered as being of less extent.
+There results, then, from the latter proportions, which we have just
+recalled, this interesting fact: that they simplify very much, from the
+point of view of design, the placing in position of the horse, on the
+condition always that this latter be always viewed directly on one of
+its lateral aspects.
+
+[Illustration: FIG. 112.--HORSE OF WHICH THE LENGTH CONTAINS MORE THAN
+TWO AND A HALF TIMES THAT OF THE HEAD, AND OF WHICH THIS DIMENSION (A,
+B) EXCEEDS THE HEIGHT.]
+
+Indeed, in this case, if we except the neck and the head, the body,
+inasmuch as its height and its length are equal, may be inscribed in a
+square, of which one of the sides corresponds to the withers and to the
+summit of the crupper, two of the other sides to the point of the arm
+and to that of the buttock the fourth being represented by the ground.
+This is simple, but this simplicity even has its inconveniences.
+
+It follows that this proportion, thus expressed, seems to exclude from
+every artistic representation certain categories of horses, which upon
+the whole might be regarded as beautiful, and the existence of which in
+any case it would be a pity not to indicate.
+
+[Illustration: FIG. 113.--HORSE OF WHICH THE LENGTH CONTAINS MORE THAN
+TWO AND A HALF TIMES THAT OF THE HEAD, AND OF WHICH THIS DIMENSION (A,
+B) EXCEEDS THE HEIGHT.]
+
+Let us examine at the outset that which is relative to the length of the
+body, equal to two and a half times the length of the head. This
+proportion is sometimes met with, and therefore may be considered exact;
+but it is necessary to add that its existence is not discoverable in the
+majority of cases. That for some authors it constitutes a perfect model
+we will not gainsay, but it is our impression that, when it exists, the
+head appears a little large, or, more exactly, the body a little short.
+
+Without attaining exactly to three times the length of the head, as some
+authors (Saint-Bel, Vallon) have announced, the body of the horse,
+nevertheless, measured as is stated above, frequently contains it more
+than two and a half times. We give in support of this some outline
+reproductions, executed after photographs (Figs. 112, 113, 114).
+
+There still remains the question regarding the equality of the height
+and of the length of the body of the horse.
+
+This equality, after the proportions previously indicated, would seem
+bound to appear in all the cases observed. Now, if we measure the
+examples reproduced in Figs. 112, 113, and 114, we shall see that
+sometimes the two dimensions are unequal, the height being greater than
+the length, or inversely.
+
+[Illustration: FIG. 114.--HORSE OF WHICH THE LENGTH CONTAINS MORE THAN
+TWO AND A HALF TIMES THAT OF THE HEAD, AND OF WHICH THIS DIMENSION (A,
+B) IS INFERIOR TO THE HEIGHT.]
+
+It is the same, if we examine a certain number of specimens; we are able
+to determine that the proportion chosen in preference by authors is not
+exactly that which is oftenest met with. It will, very probably, be
+objected that it is so for the most beautiful types, and that the
+indifferent ones are generally the more numerous. The essential thing
+would be to know, above all, if the type of two heads and a half of
+length and of height is really the only beautiful one. However that may
+be, of the fifty African horses measured by M. Duhousset, only fourteen
+possessed the equality indicated; twenty-six were less long than high,
+and ten more long than high.[68]
+
+  [68] E. Duhousset, 'The Horse,' Paris, 1881.
+
+
+
+
+CHAPTER V
+
+THE PACES OF THE HORSE
+
+
+As a completion of the studies we have just been making, some notions
+relative to the paces of the horse seem to us to be absolutely
+indicated.
+
+Let it be permitted to us to remind the reader in this connection that
+we have already been for twenty-one years occupied with this question,
+and that by means of an articulated figure, a sort of movable mannikin,
+we have endeavoured to demonstrate to artists the differences which
+characterize the various paces of the horse.[69] The arrangement then
+employed cannot, evidently, be used in the present volume, but we will
+inspire ourselves, in the preparation of the present chapter, with the
+elements of demonstration which we have employed, and which, in the
+course of our teaching, we have had the satisfaction of seeing
+favourably received.
+
+  [69] Édouard Cuyer, 'Les Allures du Cheval,' demonstrated with the aid
+       of a coloured, separable, and articulated table, Paris, 1883.
+
+       This table was the subject of a note communicated to the Academy
+       of Sciences by Professor Marey ('Comptes rendus de l'Académie de
+       Sciences') at the meeting of June 26, 1882. On the other hand, it
+       has been the subject of a presentation which we have had the
+       honour of being permitted to make to the Academy of Fine Arts at
+       the meeting of November 4, 1882.
+
+       The fasciculus in question has been since united with a more
+       complete whole as regards the study of the horse. E. Cuyer and E.
+       Alex, 'Le Cheval: Extérieur, Structure et Fonctions, Races,' avec
+       26 planches coloriées, découpées et superposées, Paris, 1886.
+
+The progressive movements by which an individual transports himself
+from one place to another do not operate according to a unique method
+and with a constantly uniform velocity. These various modes of
+progression are designated under the name of _paces_.
+
+It is extremely difficult to analyze, by simple observation, the
+movements which characterize these gaits. Let us, for example, examine
+the displacements made by the limbs of a horse during that of walking;
+if we have no notion of these displacements, it will be, so to speak,
+impossible to determine in what order they are executed. The sight of
+the imprints left on the ground by the hoofs is not a sufficient means
+of demonstration, especially for artists. The noise made by the blows of
+these limbs, or by the little bells of different timbre suspended from
+them, are absolutely in the same case.
+
+Processes enabling us to fix or to register the paces are in every way
+preferable. Such really exist; they are: instantaneous photography and
+those which constitute the graphic method of Professor Marey. The
+results given by the photograph are certainly appreciable; but, from the
+didactic point of view, we give the preference to the graphic method,
+the general characters and the mode of application of which we now
+proceed to analyze.[70]
+
+  [70] We cannot too strongly recommend the reading of the excellent
+       works which Professor Marey has published, and which have for
+       their object the study of movements, as well as the exhibition of
+       the procedures which he has employed. E. J. Marey, 'La Machine
+       Animale,' Paris, 1873; 'La Méthode graphique dans les Sciences
+       expérimentales,' Paris, 1884; 'Le Vol des Oiseaux,' Paris, 1890;
+       'Le Mouvement,' Paris, 1894.
+
+It is necessary to understand first of all, in this connection, that
+which relates to a man's walking pace.
+
+The method of Professor Marey rests on the following principle: Suppose
+two rubber globes connected with one another by a tube. If we compress
+one of these globes, the air which it contains will be driven into the
+other, and will afterwards return when the pressure has ceased. Nothing
+more simple, evidently; but it is necessary to describe it in detail in
+order the better to comprehend that which follows: The walker who is the
+subject of experiment is furnished with special shoes (Fig. 115), having
+thick indiarubber soles, hollowed in the interior, so that the whole
+thus constituted forms a sort of hollow cushion which is compressed
+under the influence of the pressure of the foot on the ground. A tube
+which is attached to a registering apparatus, which the person who is
+walking carries in his hand, communicates with this cavity (Fig. 116).
+This apparatus is formed of a metal drum, which is closed at its upper
+part by a flexible membrane. Each time that one of the man's feet
+presses on the ground, the air contained in the cavity of the sole of
+the shoe is driven into the drum, which we have just mentioned, and the
+flexible membrane of this drum is elevated. To this membrane is attached
+a vertical rod which supports a horizontal style.
+
+[Illustration: FIG. 115.--EXPERIMENTAL SHOES, INTENDED TO RECORD THE
+PRESSURE OF THE FOOT ON THE GROUND.]
+
+When the membrane, as we have just seen, is elevated, the style is
+lifted, and then descends when the pressure of the foot ceases. It
+traces these displacements on a leaf of paper, the surface of which is
+covered with a thin layer of lamp-black, which it removes by its
+contact; different parts of this surface are successively presented to
+it, the paper being rolled round a cylinder which is turned on its axis
+by means of a clockwork movement. It is necessary to add that the
+inscription is made, in the study of the walk of man, by means of two
+styles, each corresponding to one of the feet.
+
+The tracings thus obtained, which are read from left to right, are
+sufficiently simple; but to understand them properly, it is necessary to
+remember that the style undergoes a movement of ascensional displacement
+during each pressure of a foot, and that, on the other hand, it
+descends when the latter is separated from the ground. We also see, on
+the tracing which it leaves, a line which ascends and then descends; the
+meaning of this is that first the foot presses on the ground, and is
+afterwards raised from it.
+
+[Illustration: FIG. 116.--RUNNER FURNISHED WITH THE EXPLORATORY AND
+REGISTERING APPARATUS OF THE VARIOUS PACES.]
+
+On the tracing (Fig. 117), the line D relates to the right foot; the
+line G, which is dotted so that it may not be confused with the
+preceding, corresponds to the left foot. The line G first ascends; the
+meaning of which is that the left foot presses on the ground; afterwards
+it descends: this indicates that the pressure of the foot has ceased. It
+is the same for the right foot. As we see, the pressures succeed each
+other; when the left foot touches the ground, the right is separated
+from it; when the latter presses the ground, it is the left which no
+longer rests there.
+
+The line O is related to the movements of the body, as indicated by the
+oscillations of the head. We will neglect these.
+
+But this tracing, which serves us for an example, is not, it must indeed
+be said, of very easy reading; it would be still less so if the paces of
+a horse were registered, for there would then be four lines, the
+entanglement of which would cause greater complication.
+
+These difficulties of reading need be no longer feared, if we transform
+the tracing into a notation by means of the following diagram.
+
+There are drawn (Fig. 118) below the graphic tracing two horizontal
+lines (1, 2). From the point where the line D rises (commencement of the
+pressure of the right foot), and from the point where this same line
+descends (end of the same pressure), we let fall two vertical lines
+joining the two horizontal ones mentioned above. At this plane, and
+between the two vertical lines, we mark a broad white one (_a, b_). This
+expresses, by its length, the duration of the period of pressure of the
+right foot. In doing the same for the line G, we obtain for the
+indication of a pressure of the left foot an interval of the same kind,
+in which are marked cross-lines, or which is tinted gray, in order to
+avoid all confusion with the preceding tracing.
+
+[Illustration: FIG. 117.--TRACING OF THE RUNNING OF A MAN (AFTER
+PROFESSOR MAREY.)
+
+D, Pressures and elevations of the right foot; G, pressures and
+elevations of the left foot.]
+
+This notation can, with sufficient exactitude, be compared to that which
+is employed in the musical scale. The horizontal lines 1 and 2 represent
+the _compass_. We there also see _notes_; these are the bars indicating
+the pressure, of which the value--that is to say, the duration--is
+represented by the length of these bars. It is the same with regard to
+the intervals of _silence_: these are expressed by the intervals which
+separate the pressures, and correspond to the moments in which, during
+certain paces, such as running, the body is raised from the ground.
+Besides, we see intervals of this kind on the notation reproduced (Fig.
+118) relative to the running of man.
+
+[Illustration: FIG. 118.]
+
+[Illustration: FIG. 119.]
+
+In order to make the signification of these tracings still better
+understood, we reproduce four varieties of them (Fig. 119).
+
+The first notation is that of ordinary walking. The pressures succeed
+each other regularly.
+
+The second shows what takes place during the ascent of a staircase. At a
+certain moment, the weight of the body is upon both feet at the same
+time, one of them not quitting the lower step, until the other is
+already in contact with the step above. Accordingly, there is thus
+produced an overriding of the pressures.
+
+The third is relative to running, and has already been represented in
+Fig. 118. The pressures of the feet are separated by the times of
+suspension.
+
+The fourth also represents running, but in this case more rapid and
+characterized by the shorter pressures, the slightly longer periods of
+suspension intervals, and the quicker succession of movements.
+
+Before putting aside the indications relating to the walking movements
+of man--indications which it was necessary to give in order to render
+intelligible those which are connected with the paces of the horse--we
+have yet to fix the value of that which we call 'a step.'
+
+It is generally admitted that a step is constituted by the series of
+movements which are produced between the corresponding phases of the
+action of one foot and that of the other--for example, between the
+moment at which the right foot commences its pressure on the ground and
+that at which the left foot commences its own. It is necessary to adopt
+here another method of looking at it, and to regard the preceding as
+being but a _half-step_. The step should then be defined as being
+constituted by the series of movements which are executed between two
+similar positions of the same foot--as, for example, between the
+commencement of a pressure of the right foot and the similar phase of
+the following pressure of the same foot. We shall soon understand the
+importance of this definition.
+
+Before entering on the details of the paces of the horse, it is
+necessary to see how the limbs of the latter oscillate during the period
+of a complete step; or, which is the same thing, to determine what the
+displacements are which a limb executes between two similar positions of
+its foot.
+
+If we examine one of the limbs during a forward movement of the animal,
+we see that this limb passes through two principal phases: (1) It is
+raised from the ground; (2) it resumes contact with the ground. Each of
+these phases is divided into three periods of time, which we proceed to
+analyze in connection with the anterior limb.
+
+[Illustration: FIG. 120.--SWING OF THE RAISED ANTERIOR LIMB (AFTER G.
+COLIN).[71]
+
+C, Lifting; B, suspension; A, placing.]
+
+  [71] G. Colin, 'Traité de Physiologie Comparée des Animaux,' third
+       edition, Paris, 1886.
+
+The foot quits the ground (Fig. 120, C); this may be called _lifting_;
+the limb is oblique in direction downwards and backwards. This same limb
+is flexed and carried forward (Fig. 120, B), and, as it is supported by
+the action of its flexors, this is the period named _suspension_; the
+hoof is vertical. Then the limb is carried still further forward,
+becoming extended (Fig. 120, A); the heel is lowered, and the foot,
+being oblique, is directed towards the ground; this is the _placing_.
+
+Then takes place pressure (Fig. 121). The foot has just been placed on
+the ground; the limb is oblique in direction downwards and forwards;
+this we call _commencement of the pressure_ (Fig. 121, A). Then the
+body, being carried forward, whilst the hoof, D, is fixed on the ground,
+the limb becomes vertical: this stage is _mid-pressure_ (Fig. 121, B).
+Finally, the progression of the body continuing, the limb becomes
+oblique downwards and backwards; it is now at the _termination of
+pressure_ (Fig. 121, C), and proceeds to lift itself anew if another
+step is to be made.
+
+In conclusion, the inferior extremity of the limb describes, from its
+elevation to its being placed on the ground, an arc of a circle around
+its superior extremity (Fig. 121, D); whilst, during the pressure, it is
+its superior extremity which describes one around its inferior
+extremity, then fixed on the ground (Fig. 121, D).
+
+[Illustration: FIG. 121.--SWING OF THE ANTERIOR LIMB ON THE POINT OF
+PRESSURE (AFTER G. COLIN).
+
+A, Commencement of the pressure; B, centre of the pressure; C,
+termination of the pressure.]
+
+If we simultaneously examine the two fore-limbs, we remark that when one
+of them begins its pressure the other ends it, and _vice versâ_.
+
+As to the hind-limbs, the oscillations are similar to those of the fore
+ones. In the second half of the pressure--that is, when they are passing
+from the vertical direction (Fig. 122, A) to extreme obliquity backwards
+(Fig. 122, C)--the effect of their action is to give propulsion to the
+body.
+
+The fore and hind limbs make the same number of steps, and the steps
+have the same length.
+
+The limbs of any quadruped--but we make special allusion to those of
+the horse--are divided into groups in the following manner:
+
+The anterior pair constitutes the _anterior biped_. The _posterior
+biped_ is that formed by the posterior limbs.
+
+The name of _lateral biped_ serves to designate the whole formed by the
+two limbs of the same side. The right fore-limb and the right hind-limb
+form the _right lateral biped_. The two others form the _left lateral
+biped_.
+
+[Illustration: FIG. 122.--POSTERIOR LIMB, GIVING THE IMPULSE (AFTER G.
+COLIN).
+
+A, Commencement of pressure; B, centre of pressure; C, termination of
+pressure.]
+
+A fore-limb and hind-limb belonging to the opposite side form a
+_diagonal biped_, which also takes the name of the fore-limb which forms
+a part of it. Thus, _the right diagonal biped_ is formed by the
+association of the right fore-limb and the left hind one. The _left
+diagonal biped_ is, consequently, the inverse.
+
+It is necessary to remember well these preliminary indications; it is
+the only means of comprehending with facility that which is about to
+follow.
+
+Let us first return to the grouping of the limbs. The denominations
+_anterior_ and _posterior bipeds_ render clearly perceptible the
+comparison which consists in regarding a horse when walking as capable
+of being represented by two men marching one behind the other, and
+making the same number of steps. According as they move the legs of the
+same side at the same time in 'covering the step,' or march in
+contretemps step, we find reproduced all the rhythms which characterize
+the different paces of the horse.
+
+[Illustration: FIG. 123.--NOTATION OF THE AMBLING GAIT IN THE HORSE
+(AFTER PROFESSOR MAREY).]
+
+Professor Marey has studied these paces by a similar method to that
+which he adopted for the walking of man, and which we have already
+described. He employed hollow balls fixed under the hoofs, and a
+registering apparatus with four styles, each corresponding to one of the
+limbs. The tracing obtained is rather complicated, since two sets of
+lines are found marked. But a notation similar to that of which we have
+spoken can be discovered, and its exact signification should now be
+determined. For this purpose, we have selected the most simple (see Fig.
+123). We there see, placed in two superimposed lines, the pressure
+markings of the right feet (white bands), and of the left feet (gray
+bands). On the upper line are found those related to the fore-legs; the
+lower lines contain those associated with the hind-legs. It is, in
+brief, the superposition of two notations of the human walking
+movements. And seeing that, as we have previously pointed out, we may
+make a comparison between a quadruped and two men placed one behind the
+other, it is easy to understand the significance of the superimposed
+notations, if we accustom ourselves to look on them as the notations of
+two bipeds.
+
+To read these notations--that is, to learn to know what occurs at each
+of the movements of the pace--it is necessary, indeed, to remember that
+they should be examined in vertical sections; it is to each of these
+sections--of these vertical divisions--that each of the movements which
+we more particularly wish to analyze corresponds.
+
+We proceed to study first the pace of ambling, because it is the most
+simple; we shall then consider the trot, and, finally, we shall examine
+that which is the most complicated, viz., the step.
+
+[Illustration: FIG. 124.--THE AMBLE: RIGHT LATERAL PRESSURE.[72]]
+
+  [72] The figures which, in the present study, reproduce the different
+       paces, have been made from our articulated horse (see the note on
+       p. 282).
+
+=The Amble.=--To give an exact idea of the general character of the
+amble, let us fancy the two men whom we discussed above marching one
+behind the other and walking in step--that is, moving the legs of the
+same side simultaneously. They will thus represent the amble, which,
+indeed, results from the alternate displacements of the lateral bipeds;
+the limbs of the same side (right or left) execute the same movements in
+the same time.
+
+This is what the notation indicates (Fig. 123). We there see that the
+pressures of the right fore-foot, marked by the white bands in the upper
+range, are exactly superposed on those of the right hind one, which are
+marked by a similar band on the lower line; this means that the
+pressures took place in the same time. We there see also a similar
+arrangement of the gray bands, which has a similar significance for the
+left fore and hind feet.
+
+And if we recollect the three phases of pressure (see p. 289, and Figs.
+121, 122), we shall comprehend, in looking at the diagrams, that, at the
+initial stage (A), the limbs are commencing their pressure, and are
+oblique downwards and forwards; that afterwards (B) the two limbs are
+vertical, since they are at the middle of the pressure stage; and that
+finally (C) they are oblique downwards and backwards, for it is then the
+termination of their pressure (Fig. 124).
+
+[Illustration: FIG. 125.--NOTATION OF THE GAIT OF THE TROT IN THE HORSE
+(AFTER PROFESSOR MAREY).]
+
+During the time that the right limbs are pressing (notation, white
+bands) the left limbs are raised; afterwards these latter take up the
+pressure (gray bands), and then the right limbs are raised in their
+turn.
+
+During the pace of ambling the weight of the body, which is wholly
+sustained by the limbs of one side only, is not in equilibrium, so that
+the limbs which are raised return by a brisk movement to the position of
+support in order to re-establish it.
+
+=The Trot.=--We have just seen that, in order to represent the amble,
+the two marchers moved their right limbs simultaneously, and then their
+left ones.
+
+Let us suppose now that the hinder man anticipated by half a pace the
+movement of the front one, then will be found realized the association
+and the nature of the displacements of the limbs during the pace of the
+trot.
+
+By this anticipation of a half-step (we have defined, p. 288, what is to
+be understood by the word _step_), it follows that when the marcher who
+is in front advances his right leg it is the left leg of the marcher who
+follows him that is carried in the same direction. We should thus
+conclude from this that the trot is characterized by a succession of
+displacements of the diagonal bipeds.
+
+[Illustration: FIG. 126.--THE TROT; RIGHT DIAGONAL PRESSURE.]
+
+[Illustration: FIG. 127.--THE TROT; TIME OF SUSPENSION.]
+
+Indeed, if we examine the notation of this gait (Fig. 125), we see that
+with the pressure of the right fore-foot is found associated the
+pressure of the left hind-foot. It is, accordingly, a typical diagonal
+biped (Fig. 126).
+
+[Illustration: FIG. 128.--NOTATION OF THE PACE OF STEPPING IN THE HORSE
+(AFTER PROFESSOR MAREY).
+
+L, Right lateral pressure; D, right diagonal pressure; L´, left lateral
+pressure; D´, left diagonal pressure.]
+
+But it is necessary to add that these groups of pressures do not succeed
+one another without interruption, except in the slow trot. In the
+ordinary trot, or in that in which the animal's strides are very long,
+the body between each of the double pressures which we have just been
+considering is projected forward with such force that it remains for an
+instant separated from the ground. This is what we designate by the name
+of _time of suspension_ (Fig. 127). The notation in this case would be
+slightly different from that which we reproduce above, in this sense:
+that between the diagonal pressures there then would be found an
+interval, since during the time the body is suspended none of the feet
+can produce a pressure-mark (see, with regard to these intervals, the
+notations of the running of a man, Fig. 118, and Fig. 119, 3, 4).
+
+=The Walk.=--Although slow, a feature which would seem to make it
+possible to permit its analysis in a horse when walking, this pace is
+difficult to comprehend without sufficient preliminary study.
+
+[Illustration: FIG. 129.--THE STEP: RIGHT LATERAL PRESSURE.]
+
+[Illustration: FIG. 130.--THE STEP: RIGHT DIAGONAL PRESSURE.]
+
+We saw above that in order to represent the amble the marchers had to
+move the legs of the same side simultaneously. We have also just seen
+that in order to represent the trot the marcher at the back had to
+anticipate by a half-step. Suppose, now, that this same marcher
+anticipates the man in front by a quarter-step only, or by a
+half-pressure period, and thus will be found realized the order of
+succession of the limbs in the gait or pace called the _walk_. The feet
+meet the ground one after the other, since they are each in advance by
+half the duration of a pressure. The strokes are four in number during
+the period of a step of this pace; in the amble and in the trot they do
+not exceed two, for then the limbs strike the ground in lateral diagonal
+pairs.
+
+[Illustration: FIG. 131.--THE GALLOP: FIRST PERIOD.]
+
+[Illustration: FIG. 132.--THE GALLOP: SECOND PERIOD.]
+
+[Illustration: FIG. 133.--THE GALLOP: THIRD PERIOD.]
+
+[Illustration: FIG. 134.--THE GALLOP: TIME OF SUSPENSION.]
+
+If we examine the notation of the pace of walking (Fig. 128), we see
+that the right fore-foot commences its pressure when the right
+hind-foot is in the middle of its own, and that the hinder left begins
+in the middle of that of the right fore-foot, and that it is itself at
+the midst of its pressure when the left fore-foot touches the ground,
+etc. In a word, the foot-fallings occur in the following order and at
+regular intervals--the fore right foot is here considered as acting
+first: right fore, left hind, left fore, right hind, and so on in
+succession.
+
+[Illustration: FIG. 135.--NOTATION OF THE GALLOP DIVIDED INTO THREE
+PERIODS OF TIME (AFTER PROFESSOR MAREY).
+
+1, First period; 2, second period; 3, third period.]
+
+As to the nature of the bipeds which succeed one another, it is easy to
+understand them by means of the notation. In reading this from left to
+right, we see that the associations of pressure are first made by the
+two right feet, then by a right foot and a left one, then by two left
+feet, and, finally, by a left and right. It is, accordingly, a
+succession this time of lateral and diagonal pressures.
+
+[Illustration: FIG. 136.--NOTATION OF THE GALLOP OF FOUR PERIODS IN THE
+HORSE (AFTER PROFESSOR MAREY).
+
+1, First period; 2, second period; 3, third period; 4, fourth period.]
+
+Thus, we find at the start a right lateral pressure (Fig. 129), next a
+right diagonal (Fig. 130), then a left lateral; finally, a left diagonal
+pressure. It is thus that the initial letters L, D, L´, D´ further
+indicate the notations represented in Fig. 128.
+
+=The Gallop.=--The ordinary gallop is a pace of three phases. The first
+is characterized by the fact that one hind-limb alone rests on the
+ground (Fig. 131); in the second the animal is on a diagonal support
+(Fig. 132); in the third it comes down on a fore-limb (Fig. 133). The
+body is then raised (Fig. 134), and to this period of suspension succeed
+anew the three modes of pressure indicated above.
+
+The gallop is said to be from either right or left. In the gallop from
+the right, the right fore-leg is the more frequently in advance of its
+neighbour; it is the last to be placed on the ground. The left foot of
+the posterior biped is the one which commences the action.
+
+An entirely opposite arrangement characterizes the gallop from the left.
+
+[Illustration: FIG. 137.--LEAP OF THE HARE (AFTER G. COLIN).]
+
+The notation reproduced in Fig. 135 corresponds to the gallop from the
+right. It is there seen, as we pointed out above, that in the first
+phase the exclusive support of the left hind-foot takes place (1); that
+afterwards, in the second, commence simultaneously, the pressures of the
+left fore and the right hind foot (2); this is the left diagonal
+support; and that finally, in the third, the body comes down on a
+fore-limb, which is then the right (3); and that for a moment it is on
+this limb alone that the animal rests.
+
+To these three phases on the notation succeeds an interval; this is the
+period of suspension.
+
+The gallop of four phases only differs from the preceding in that the
+foot-fallings of each diagonal biped occur at slight intervals, and give
+distinct sounds. The notation is reproduced in Fig. 136.
+
+[Illustration: FIG. 138.--THE LEAP.]
+
+[Illustration: FIG. 139.--THE LEAP.]
+
+[Illustration: FIG. 140.--THE LEAP.]
+
+[Illustration: FIG. 141.--THE LEAP.]
+
+=The Leap.=--The leap is an act by which the body is wholly raised from
+the ground and projected upwards and forwards to a greater or less
+distance.
+
+It is prepared for by the flexing of the hind-limbs, which, by being
+suddenly extended, project the body, and thus enable it to pass over an
+obstacle.
+
+This preparatory arrangement is very remarkable in the leap of the lion,
+the cat, and the panther, which execute springs of great length; in the
+horse, in which the leap is not an habitual mode of progression, this
+flexion of the hinder limbs is less marked. With this animal the leap is
+generally associated with the gallop; nevertheless, it is sometimes made
+from a stationary position. In observing the hare or the rabbit, in
+which the leap is habitual, we notice (Fig. 137) that the hind-limbs,
+being extremely flexed, rest on the ground as far as the calcaneum, are
+then straightened by the action of their extensors, become vertical and
+then oblique backwards at the moment the body is thrown forward into
+space by the sudden extension of these limbs.
+
+The action of the extensors is energetic and instantaneous, and their
+energy is greater than in ordinary progression, for it is required to
+lift the body and to project it forcibly a more or less considerable
+distance. It is the extreme rapidity of this action which enables the
+animal to clear an obstacle, for without this condition the body would
+be raised, but not separated from the ground.
+
+First of all, in reaching the obstacle to be cleared, the horse prepares
+to leap by taking the attitude of rearing; the hind-limbs are flexed and
+carried under the body, the fore-quarters are raised, and the different
+segments of the fore-limbs are flexed (Fig. 138).
+
+[Illustration: FIG. 142.--THE LEAP.]
+
+[Illustration: FIG. 143.--THE LEAP.]
+
+One sudden trigger action produced by the violent contraction of the
+extensors of the hind-legs then takes place, and the animal is projected
+forwards, while he flexes the fore-legs more and more (Fig. 139). He
+has then risen above the obstacle (Fig. 140). Then while he makes the
+downward and forward balancing movement, and points his fore-limbs in
+the same direction, he flexes the hind ones (Fig. 141). Whilst the
+latter are further flexed, in order to pass the obstacle in their turn,
+the fore-limbs which are extended come into contact with the ground
+(Fig. 142). Finally, in the last phase of the leap, the animal, raising
+himself in front, after the impact of his hind-feet has taken place
+(Fig. 143), prepares to continue the pace at which he progressed before
+meeting the obstacle which he had to clear.
+
+
+THE END
+
+
+_London: Baillière, Tindall and Cox, 8, Henrietta Street, Covent Garden,
+W.C._
+
+
+
+
+  THE
+  ARTISTIC ANATOMY OF ANIMALS
+
+[Illustration]
+
+
+
+
+SECTIONAL INDEX
+
+
+                                                                   PAGE
+
+  =Generalities of Comparative Anatomy=                               1
+
+
+  OSTEOLOGY AND ARTHROLOGY
+
+  =The Trunk:=
+    _Vertebral Column_                                                4
+      Sacrum                                                         10
+      Coccygeal vertebræ                                             11
+      Direction and form of the vertebral column                     11
+    _Thorax_                                                         12
+      Sternum                                                        14
+      Ribs and costal cartilages                                     14
+
+  =The Anterior Limbs:=
+    _Shoulder_                                                       20
+      Scapula                                                        21
+      Clavicle                                                       25
+    _Arm_                                                            28
+      Humerus                                                        28
+    General view of the form of the forearm and hand                 34
+      Forearm                                                        38
+      Hand                                                           44
+
+  =The Anterior Limbs in Certain Animals:=
+    _Plantigrades_: Bear                                             49
+    _Digitigrades_: Cat, dog                                         51
+    _Unguligrades_: Pig                                              57
+      Sheep, Ox                                                      60
+      Horse                                                          64
+    Proportions of the arm, the forearm, and metacarpus              70
+    Articulations of the anterior limbs                              71
+      Scapulo-humeral articulation                                   72
+      Humero-ulnar articulation, or elbow                            74
+      Radio-ulnar articulation                                       75
+      Articulation of the wrist                                      75
+      Metacarpo-phalangeal articulations                             76
+      Interphalangeal articulations                                  77
+
+  =The Posterior Limbs:=
+    _Pelvis_                                                         78
+      Iliac bone                                                     78
+    _The Thigh_                                                      83
+      Femur                                                          83
+      Knee-cap                                                       85
+    _The Leg_                                                        85
+      Tibia                                                          86
+      Fibula                                                         87
+    _The Foot_                                                       87
+
+  =The Posterior Limbs in Some Animals:=
+    _Plantigrades_: Bear                                             90
+    _Digitigrades_: Cat, dog                                         91
+    _Unguligrades_: Pig                                              94
+      Sheep, ox                                                      95
+      Horse                                                          99
+    Articulations of the posterior limbs                            105
+      Coxo-femoral articulation                                     105
+      Femoro-tibial articulation, or knee                           106
+      Tibio-tarsal articulation, and of the bones of the tarsus     107
+
+  =The Head in General, and in Some Animals in Particular:=
+    Direction of the head                                           109
+    The skull                                                       112
+    The face                                                        118
+    The skull of birds                                              127
+
+
+  MYOLOGY
+
+  =Muscles of the Trunk:=
+    Pectoralis major                                                131
+    Pectoralis minor                                                133
+    Serratus magnus                                                 134
+
+  =Muscles of the Abdomen:=
+    External oblique                                                136
+    Internal oblique                                                137
+    Transversalis abdominis                                         138
+    Rectus abdominis                                                138
+    Pyramidalis abdominis                                           139
+
+  =Muscles of the Back:=
+    Trapezius                                                       140
+    Latissimus dorsi                                                142
+    Rhomboid                                                        144
+
+  =The Cutaneous Muscle of the Trunk=                               147
+
+  =The Coccygeal Region:=
+    Ischio-coccygeal muscle                                         149
+    Superior sacro-coccygeal muscle                                 150
+    Lateral sacro-coccygeal muscle                                  150
+    Inferior sacro-coccygeal muscle                                 150
+
+  =Muscles of the Neck:=
+    Mastoido-humeralis                                              150
+    Sterno-mastoid                                                  153
+    Omo-trachelian                                                  155
+    Levator anguli scapulæ                                          156
+    Splenius                                                        158
+
+  =Infrahyoid Muscles:=
+    Sterno-thyroid and sterno-hyoid                                 160
+    Omo-hyoid                                                       160
+
+  =Suprahyoid Muscles:=
+    Mylo-hyoid                                                      161
+    Digastric                                                       161
+
+  =Panniculus of the Neck=                                          162
+
+  =Muscles of the Anterior Limbs:=
+    _Muscles of the Shoulder_                                       162
+      Deltoid                                                       162
+      Subscapularis                                                 163
+      Supraspinatus                                                 164
+      Infraspinatus                                                 165
+      Teres minor                                                   166
+      Teres major                                                   166
+      Panniculus muscle of the shoulder                             167
+    _Muscles of the Arm_                                            168
+      Anterior region                                               169
+        Biceps                                                      169
+        Brachialis anticus                                          170
+        Coraco-brachialis                                           170
+      Posterior region                                              171
+        Triceps                                                     171
+      _Supplemental or Accessory Muscle of the Latissimus Dorsi_    173
+    _Muscles of the Forearm_                                        174
+      Anterior and external region                                  176
+        Supinator longus                                            176
+        First and second external radial                            176
+        Supinator brevis                                            179
+        Extensor communis digitorum                                 179
+        Extensor minimi digiti                                      183
+        Posterior ulnar                                             185
+        Anconeus                                                    185
+        Long abductor of the thumb                                  186
+        Short extensor of the thumb                                 187
+        Long extensor of the thumb                                  187
+        Proper extensor of the index                                187
+      Internal and posterior region                                 188
+        Pronator teres                                              188
+        Flexor carpi radialis                                       189
+        Palmaris longus                                             189
+        Anterior ulnar                                              191
+        Superficial flexor of the digits                            193
+        Long proper flexor of the thumb                             197
+        Pronator quadratus                                          198
+    _Muscles of the Hand_                                           199
+
+  =Muscles of the Posterior Limbs:=
+    _Muscles of the Pelvis_                                         200
+      Gluteus medius                                                200
+      Gluteus maximus                                               201
+    _Muscles of the Thigh_                                          204
+      Muscles of the posterior region                               205
+        Biceps                                                      205
+        Semi-tendinosus                                             206
+        Semi-membranosus                                            207
+      Muscles of the anterior region                                210
+        Triceps                                                     210
+        Tensor fascia lata                                          211
+        Sartorius                                                   211
+      Muscles of the internal region                                213
+        Gracilis                                                    213
+    _Muscles of the Leg_                                            213
+      Muscles of the anterior region                                214
+        Tibialis anticus                                            214
+        Extensor proprius pollicis                                  219
+        Extensor longus digitorum                                   219
+        Peroneus tertius                                            224
+      Muscles of the external region                                224
+        Peroneus longus                                             224
+        Peroneus brevis                                             225
+      Muscles of the posterior region                               227
+        Gastrocnemius                                               227
+        Soleus                                                      228
+        Plantaris                                                   228
+        Popliteus                                                   228
+        Superficial flexor of the toes                              229
+        Flexor longus digitorum                                     230
+        Tibialis posticus                                           230
+        Flexor longus pollicis                                      231
+    _Muscles of the Foot_                                           231
+        Dorsalis pedis                                              231
+    _Muscles of the Head_                                           232
+      Masticatory muscles                                           232
+      Masseter                                                      232
+      Temporal muscle                                               234
+      Cutaneous muscles of the head                                 234
+        Occipito-frontalis                                          234
+        Orbicularis palpebrarum                                     234
+        Pyramidalis nasi                                            235
+        Corrugator supercilii                                       235
+        Zygomaticus major                                           235
+        Zygomaticus minor                                           236
+        Levator labii superioris proprius                           237
+        Levator labii superioris alæque nasi                        238
+        Transversus nasi                                            239
+        Caninus                                                     239
+        Orbicularis oris                                            240
+        Triangularis oris                                           240
+        Quadratus menti                                             240
+        Prominence of the chin                                      240
+        Buccinator                                                  241
+          Maxillo-labialis                                          242
+        Zygomatico-auricularis                                      242
+        Temporo-auricularis externus                                243
+        Scuto-auricularis externus                                  243
+        Cervico-auricular muscles                                   243
+        Cervico-auricularis superioris                              244
+        Cervico-auricularis medius                                  244
+        Cervico-auricularis inferioris                              244
+        Parotido-auricularis                                        244
+        Temporo-auricularis internus                                244
+        Zygomatico-auricularis                                      245
+
+
+  EPIDERMIC PRODUCTS OF THE TERMINAL EXTREMITIES OF THE FORE AND
+  HIND LIMBS
+
+  Claws                                                             247
+  Plantar tubercles                                                 248
+  Hoofs of the solipeds                                             250
+  Hoofs of ox and pig                                               261
+
+         *       *       *       *       *
+
+  Proportions                                                       262
+  Proportions of head of horse                                      273
+    (front view)                                                    276
+
+  Paces of the horse                                                282
+    Amble                                                           293
+    Trot                                                            294
+    Walk                                                            296
+    Gallop                                                          300
+    Leap                                                            364
+
+
+
+
+ERRATA
+
+
+P. 105, _Articulations_ of the Posterior Limbs.
+
+P. 107, Tibio-tarsal _Articulation_.
+
+
+
+
+THE END
+
+
+_London: Baillière, Tindall and Cox, 8, Henrietta Street, Covent Garden,
+W.C._
+
+
+
+
+  +--------------------------------------------------------------------+
+  |                       TRANSCRIBER'S NOTES:                         |
+  |                                                                    |
+  | Footnotes have been moved to underneath the paragraph, table or    |
+  | illustration they refer to.                                        |
+  |                                                                    |
+  | Illustrations have been moved so as to not disrupt the flow of the |
+  | text. Page numbers in the List of Illustrations and in references  |
+  | have not been changed, and are therefore not always correct.       |
+  |                                                                    |
+  | The Table of Contents and the Sectional Index are not complete and |
+  | contain slightly different wording than the names of sections in   |
+  | the text. This has been left as in the original work.              |
+  |                                                                    |
+  | The Errata have already been changed in the text.                  |
+  |                                                                    |
+  | The author uses the terms chromophotograph and chronophotograph    |
+  | (and derivations of these words); these words have not been        |
+  | changed. The correct term in these cases is chronophotograph.      |
+  |                                                                    |
+  | Page 143, Fig. 69: atlas is mentioned twice (nrs. 12 and 13); only |
+  | nr. 13 indicates the atlas.                                        |
+  |                                                                    |
+  | The text used is that of the original work, including              |
+  | inconsistencies in spelling, hyphenation and lay-out, and          |
+  | differences between main text, footnotes and captions, except when |
+  | mentioned below.                                                   |
+  |                                                                    |
+  | Changes made to the text:                                          |
+  |   Some minor obvious typographical errors have been corrected      |
+  |   silently.                                                        |
+  |   Periods have been removed from some section headings for         |
+  |   consistency.                                                     |
+  |   Page 2, footnote [2]: Mathias-Duval changed to Mathias Duval     |
+  |   (full name: Mathias-Marie Duval).                                |
+  |   Page 23: _see_ replaced with see for consistency.                |
+  |   Page 44 (footnote 12): Edward Cuyer changed to Édouard Cuyer as  |
+  |   elsewhere.                                                       |
+  |   Page 53, captions (2x): AA¹ changed to AA´ as in drawing and     |
+  |   text.                                                            |
+  |   Page 120, Fig. 63, caption: 14´, malar bone added, 14 changed to |
+  |   anterior orifice of the cavity of the nasal fossæ (as in previous|
+  |   figures).                                                        |
+  |   Page 216: tendo-Achilles changed to tendo-Achillis as elsewhere. |
+  |   Page 234: Fig. 0, 92 changed to Fig. 90, 2.                      |
+  |   Page 254, Fig. 98: epternal changed to external.                 |
+  |   Page 269, last paragraph: one anchor to same footnote deleted.   |
+  |   Page 325: L, D, L', D' changed to L, D, L´, D´.                  |
+  |   Footnotes 13, 17: La Natura changed to La Nature.                |
+  +--------------------------------------------------------------------+
+
+
+
+
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+      The Project Gutenberg eBook of The Artistic Anatomy of Animals, by &Eacute;douard Cuyer.
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+<pre>
+
+The Project Gutenberg EBook of Artistic Anatomy of Animals, by Édouard Cuyer
+
+This eBook is for the use of anyone anywhere at no cost and with
+almost no restrictions whatsoever.  You may copy it, give it away or
+re-use it under the terms of the Project Gutenberg License included
+with this eBook or online at www.gutenberg.org
+
+
+Title: Artistic Anatomy of Animals
+
+Author: Édouard Cuyer
+
+Release Date: December 15, 2011 [EBook #38315]
+
+Language: English
+
+Character set encoding: ISO-8859-1
+
+*** START OF THIS PROJECT GUTENBERG EBOOK ARTISTIC ANATOMY OF ANIMALS ***
+
+
+
+
+Produced by Chris Curnow, Harry Lamé and the Online
+Distributed Proofreading Team at https://www.pgdp.net (This
+file was produced from images generously made available
+by The Internet Archive)
+
+
+
+
+
+
+</pre>
+
+
+<div class="bbox" style="padding: 1em; margin-left: 25%; margin-right: 25%;">
+<p class="center">Please see <a href="#TN">Transcriber's Notes</a> at the end of this document.</p>
+</div>
+
+<h1><span class="fsize80">THE</span><br />
+ARTISTIC ANATOMY OF ANIMALS</h1>
+
+<hr class="c25" />
+
+<div class="figcenter">
+<img src="images/title.png" alt="ARTISTIC&middot;ANATOMY&middot;OF&middot;ANIMALS&middot;
+BY&middot;&Eacute;DOUARD&middot;CUYER&middot;
+SUPPLEMENTARY&middot;PROF&middot;OF&middot;ANATOMY&middot;AT&middot;THE&middot;SCHOOL&middot;OF&middot;
+FINE&middot;ART&middot;PARIS&middot;
+PROF&middot;OF&middot;ANATOMY&middot;
+AT&middot;THE&middot;SCHOOL&middot;OF&middot;FINE ART ROUEN&middot;
+TRANSLATED &amp; EDITED&middot;BY&middot;
+GEORGE&middot;HAYWOOD&middot;
+LECTURER&middot;ON&middot;ANATOMY&middot;AT&middot;THE&middot;ROYAL&middot;
+COLLEGE&middot;OF&middot;ART&middot;SOUTH KENSINGTON&middot;&middot;
+LONDON&middot;
+BAILLI&Egrave;RE, TINDALL &amp; COX&middot;
+8&middot;HENRIETTA&middot;ST&middot;COVENT&middot;GARDEN&middot;
+ANNO&middot;DOMINI&middot;
+MDCCCCV&middot;
+ALL&middot;RIGHTS&middot;
+RESVD" width="341" height="550" /></div>
+
+<hr class="c25" />
+<p class="pagenum"><a name="Page_v" id="Page_v">[v]</a></p>
+<h2>PREFACE</h2>
+
+<p>A few lines will suffice to explain why we have compiled
+the present volume, to what wants it responds, and what
+its sphere of usefulness may possibly embrace.</p>
+
+<p>In our teaching of plastic anatomy, especially at the &Eacute;cole
+des Beaux-Arts&mdash;where, for the past nine years, we have
+had the very great honour of supplementing the teaching
+of our distinguished master, Mathias Duval, after having
+been prosector for his course of lectures since 1881&mdash;it is
+our practice to give, as a complement to the study of human
+anatomy, a certain number of lessons on the anatomy of
+those animals which artists might be called on to represent.</p>
+
+<p>Now, we were given to understand that the subject
+treated in our lectures interested our hearers, so much so
+that we were not surprised to learn that a certain number
+repeatedly expressed a desire to see these lectures united
+in book form.</p>
+
+<p>To us this idea was not new; for many years the work in
+question had been in course of preparation, and we had
+collected materials for it, with the object of filling up a
+void of which the existence was to be regretted. But our
+many engagements prevented us from executing our project
+as early as we would have wished. It is this work
+which we publish to-day.</p>
+
+<p class="pagenumpic"><a name="Page_vi" id="Page_vi">[vi]</a></p>
+
+<div class="figlarge"><a name="FigI" id="FigI"></a>
+<img src="images/illo007.jpg" alt="Fig. I" width="600" height="315" />
+<p class="caption just">Fig. I.&mdash;Reproduction of a Sketch by Barye (Collections of the Anatomical Museum of the &Eacute;cole des
+Beaux-Arts&mdash;Huguier Museum).</p></div>
+
+<p>Putting aside for a moment the wish expressed by our
+hearers, we feel ourselves in duty bound to inquire whether
+the utility of this publication is self-evident. Let it be
+clearly understood that we wish to express here our opinion<span class="pagenum"><a name="Page_vii" id="Page_vii">[vii]</a></span>
+on this subject, while putting aside every personal sentiment
+of an author.</p>
+
+<p>No one now disputes the value of anatomical studies
+made in view of carrying out the artistic representation of
+man. Nevertheless&mdash;for we must provide against all contingencies&mdash;the
+conviction on this subject may be more or
+less absolute; and yet it must possess this character in an
+intense degree in order that these studies may be profitable,
+and permit the attainment of the goal which is
+proposed in undertaking them. It is in this way that we
+ever strive to train the students whose studies we direct;
+not only to admit the value of these studies, but to be
+materially and deeply convinced of the fact without any
+restriction. Such is the sentiment which we endeavour to
+create and vigorously encourage. And we may be permitted
+to add that we have often been successful in this
+direction.</p>
+
+<p>Therefore it is that, at the beginning of our lectures, and
+in anticipation of possible objections, we are accustomed
+to take up the question of the utility of plastic anatomy.
+And in so doing, it is in order to combat at the outset the
+idea&mdash;as mischievous as it is false&mdash;which is sometimes
+imprudently enunciated, that the possession of scientific
+knowledge is likely to tarnish the purity and freshness of
+the impressions received by the artist, and to place shackles
+on the emotional sincerity of their representation.</p>
+
+<p class="pagenumpic"><a name="Page_viii" id="Page_viii">[viii]</a></p>
+
+<div class="figlarge"><a name="FigII" id="FigII"></a>
+<img src="images/illo009.jpg" alt="Fig. II" width="600" height="313" />
+<p class="caption just">Fig. II.&mdash;Reproduction of a Sketch of Barye (Collections of the Anatomical Museum of the &Eacute;cole des
+Beaux-Arts&mdash;Huguier Museum).</p></div>
+
+<p>It is chiefly by employment of examples that we approach
+the subject. These strike the imagination of the
+student more forcibly, and the presentation of models of
+a certain choice, although rough in execution, is, in our
+opinion, preferable to considerations of an order possibly
+more exalted, but of a character less clearly practical. Let
+us, then, ask the question: Those artists whose eminence
+nobody would dare to question, did they study anatomy?
+If the answer be in the affirmative, we surely cannot permit
+ourselves to believe that we can dispense with a similar<span class="pagenum"><a name="Page_ix" id="Page_ix">[ix]</a></span>
+course. And, as proof of the studies of this class which
+the masters have made, we may cite Raphael, Michelangelo,
+and, above all, Leonardo da Vinci; and, of the
+moderns, G&eacute;ricault. And we may more clearly define
+these proofs by an examination of the reproductions of
+their anatomical works, chosen from certain of their special
+writings.<a name="FNanchor_1_1" id="FNanchor_1_1"></a><a href="#Footnote_1_1" class="fnanchor">[1]</a></p>
+
+<div class="footnote">
+<p><a name="Footnote_1_1" id="Footnote_1_1"></a><a href="#FNanchor_1_1"><span class="label">[1]</span></a> Mathias
+Duval and A. Bical, &#8216;L&#8217;anatomie des Ma&icirc;tres.&#8217; Thirty plates
+reproduced from the originals of Leonardo da Vinci, Michelangelo, Raphael,
+G&eacute;ricault, etc., with letterpress and a history of plastic anatomy, Paris,
+1890.</p>
+
+<p>The manuscripts of Leonardo da Vinci of the Royal Library, Windsor,
+&#8216;Anatomy, Foli&aelig; A.,&#8217; published by Th&eacute;odore Sabachnikoff, with a French
+translation, written and annotated by Giovanni Piumati, with an introduction
+by Mathias Duval. &Eacute;douard Rouveyre, publisher, Paris, 1898.</p>
+
+<p>Mathias Duval and &Eacute;douard Cuyer, &#8216;History of Plastic Anatomy: The
+Masters, their Books, and Anatomical Figures&#8217; (Library of Instruction of the
+School of Fine Arts), Paris, 1898.</p>
+</div>
+
+<p>Accordingly, there is no scope for serious discussion, and
+it only remains for us to enunciate the opinion that it is
+necessary that we should imitate those masters, and, with
+a sense of respectful discipline, follow their example.</p>
+
+<p>Here, with regard to the anatomy of animals, we pursue
+the same method, and the example chosen shall be that of
+Barye. His talent is too far above all criticism to allow
+that this example should be refused. The admiration
+which the works of this great artist elicit is too wide-spread
+for us to remain uninfluenced by the lessons furnished by
+his studies. It is sufficient to see the sketches relating
+to these studies, and his admirable casts from nature
+which form part of the anatomical museum of the &Eacute;cole
+des Beaux-Arts, to be convinced that the artistic temperament,
+of which Barye was one of the most brilliant
+examples, has nothing to lose by its association with researches
+the precision of which might seem likely to check
+its complete expansion.</p>
+
+<p class="pagenumpic"><a name="Page_x" id="Page_x">[x]</a></p>
+
+<div class="figlarge"><a name="FigIII" id="FigIII"></a>
+<img src="images/illo011.jpg" alt="Fig. III" width="600" height="372" />
+<p class="caption just">Fig. III.&mdash;Reproduction of a Sketch of Barye (Collections of the Anatomical Museum of the
+&Eacute;cole des Beaux-Arts&mdash;Huguier Museum).</p></div>
+
+<p>In those sketches we find proofs of observation so scrupulous
+that we cannot restrain our admiration for the man<span class="pagenum"><a name="Page_xi" id="Page_xi">[xi]</a></span>
+whose ardent imagination was voluntarily subjected to the
+toil of study so profound.</p>
+
+<p>If the example of Barye, with whom we associate the
+names of other great modern painters of animals, can determine
+the conviction which we seek to produce, we shall be
+sincerely glad. To contribute to the propagation of useful
+ideas, and to see them accepted, gives a feeling of satisfaction
+far too legitimate for us to hesitate to say what we
+should feel if our hope be realized in this instance.</p>
+
+<p class="right" style="margin: 1.5em 10% 1.5em auto;">&Eacute;DOUARD CUYER.</p>
+
+<p class="pagenumpic"><a name="Page_xii" id="Page_xii">[xii]</a></p>
+
+<div class="figlarge"><a name="FigIV" id="FigIV"></a>
+<img src="images/illo013.jpg" alt="Fig. IV" width="600" height="378" />
+<p class="caption just">Fig. IV.&mdash;Reproduction of a Sketch of Barye (Collections of Anatomical Museum of the
+School of Fine Arts&mdash;Huguier Museum).</p></div>
+
+<hr class="c25" />
+<p class="pagenum"><a name="Page_xiii" id="Page_xiii">[xiii]</a></p>
+<p class="leftlink"><a href="#SectionToC">Detailed<br />Table of<br />Contents.</a></p>
+<h2>CONTENTS</h2>
+
+<table summary="ToC">
+
+<tr>
+<td colspan="3" class="center fsize125" style="line-height: 2em;">INTRODUCTION</td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td class="right padl1 fsize80">PAGE</td>
+</tr>
+
+<tr>
+<td colspan="2" class="top left">GENERALITIES OF COMPARATIVE ANATOMY</td>
+<td class="right bot"><a href="#Page_1">1</a></td>
+</tr>
+
+<tr>
+<td colspan="3" class="center fsize125" style="line-height: 2em;">CHAPTER I</td>
+</tr>
+
+<tr>
+<td colspan="3" class="top left">OSTEOLOGY AND ARTHROLOGY:</td>
+</tr>
+
+<tr>
+<td style="width: 2em;">&nbsp;</td>
+<td class="left top">THE TRUNK</td>
+<td class="right bot"><a href="#Page_4">4</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td class="left top">THE POSTERIOR LIMBS</td>
+<td class="right bot"><a href="#Page_78">78</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td class="left top">THE POSTERIOR LIMBS IN SOME ANIMALS</td>
+<td class="right bot"><a href="#Page_90">90</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td class="left top">THE SKULL OF BIRDS</td>
+<td class="right bot"><a href="#Page_127">127</a></td>
+</tr>
+
+<tr>
+<td colspan="3" class="center fsize125" style="line-height: 2em;">CHAPTER II</td>
+</tr>
+
+<tr>
+<td colspan="3" class="top left">MYOLOGY:</td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td class="left top">THE MUSCLES OF THE TRUNK</td>
+<td class="right bot"><a href="#Page_131">131</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td class="left top">MUSCLES OF THE ANTERIOR LIMBS</td>
+<td class="right bot"><a href="#Page_162">162</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td class="left top">MUSCLES OF THE POSTERIOR LIMBS</td>
+<td class="right bot"><a href="#Page_200">200</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td class="left top">MUSCLES OF THE HEAD</td>
+<td class="right bot"><a href="#Page_232">232</a></td>
+</tr>
+
+<tr>
+<td colspan="3" class="center fsize125" style="line-height: 2em;">CHAPTER III</td>
+</tr>
+
+<tr>
+<td colspan="2" class="top left">EPIDERMIC PRODUCTS OF THE EXTREMITIES OF THE FORE AND HIND LIMBS</td>
+<td class="right bot"><a href="#Page_247">247</a></td>
+</tr>
+
+<tr>
+<td colspan="3" class="center fsize125" style="line-height: 2em;">CHAPTER IV</td>
+</tr>
+
+<tr>
+<td colspan="3" class="top left">PROPORTIONS</td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td class="left top">PROPORTIONS OF THE HEAD OF THE HORSE</td>
+<td class="right bot"><a href="#Page_273">273</a></td>
+</tr>
+
+<tr>
+<td colspan="3" class="center fsize125" style="line-height: 2em;">CHAPTER V</td>
+</tr>
+
+<tr>
+<td colspan="2" class="top left">THE PACES OF THE HORSE</td>
+<td class="right bot"><a href="#Page_282">282</a></td>
+</tr>
+
+</table>
+
+<p class="pagenum"><a name="Page_xiv" id="Page_xiv"></a></p>
+
+<hr class="c25" />
+<p class="pagenum"><a name="Page_xv" id="Page_xv">[xv]</a></p>
+<h2>LIST OF ILLUSTRATIONS</h2>
+
+<table style="margin: auto 10%;" summary="LoI">
+
+<tr>
+<td class="center fsize80">FIG.</td>
+<td>&nbsp;</td>
+<td class="center fsize80">PAGE</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig001">1.</a></td>
+<td class="just top"><span class="smcap">A Human Skeleton in the Attitude of a Quadruped, To give a General Idea of the Position of the
+Bones in other Vertebrates</span></td>
+<td class="right bot">5</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig002">2.</a></td>
+<td class="just top"><span class="smcap">Size of the Atlas compared with the Transverse Dimensions of the Corresponding Parts of the Skull
+in Man</span></td>
+<td class="right bot">7</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig003">3.</a></td>
+<td class="just top"><span class="smcap">Size of the Atlas compared with the Transverse Dimensions of the Corresponding Regions of the
+Skull in a Dog</span></td>
+<td class="right bot">8</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig004">4.</a></td>
+<td class="just top"><span class="smcap"> Lumbar Vertebr&aelig; of a Quadruped (the Horse): Superior Surface</span></td>
+<td class="right bot">9</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig005">5.</a></td>
+<td class="just top"><span class="smcap">A Transverse Section of the Thorax of a Man placed Vertically&mdash;that is to say, in the
+Direction which it would assume in a Man placed in the Attitude of a Quadruped (a Diagrammatic Figure)</span></td>
+<td class="right bot">13</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig006">6.</a></td>
+<td class="just top"><span class="smcap">A Vertical Section of the Thorax of a Quadruped (Diagrammatic)</span></td>
+<td class="right bot">14</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig007">7.</a></td>
+<td class="just top"><span class="smcap">Sternum of a Bird (the Cock): Left Side, External Surface</span></td>
+<td class="right bot">17</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig008">8.</a></td>
+<td class="just top"><span class="smcap">Anterior Limb of the Bat: Left Side, Anterior Surface</span></td>
+<td class="right bot">20</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig009">9.</a></td>
+<td class="just top"><span class="smcap">Anterior Limb of the Seal: Left Side, External Surface</span></td>
+<td class="right bot">21</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig010">10.</a></td>
+<td class="just top"><span class="smcap">Situation and Direction of the Scapula in the Human Being, the Trunk being Horizontal, as in
+Quadrupeds. Vertical and Transverse Section of the Thorax (Diagrammatic Figure)</span></td>
+<td class="right bot">22</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig011">11.</a></td>
+<td class="just top"><span class="smcap">Position and Direction of the Scapula in Quadrupeds. Vertical and Transverse Section of the
+Thorax (Diagrammatic Figure)</span></td>
+<td class="right bot">22</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig012">12.</a></td>
+<td class="just top"><span class="smcap">Left Scapula of the Human Being, Posterior Surface, placed in the Position which it would Occupy
+in the Skeleton of a Quadruped</span></td>
+<td class="right bot">23</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig013">13.</a></td>
+<td class="just top"><span class="smcap">Left Scapula of a Horse: External Surface</span></td>
+<td class="right bot">23</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig014">14.</a><span class="pagenum"><a name="Page_xvi" id="Page_xvi">[xvi]</a></span></td>
+<td class="just top"><span class="smcap">Vertical and Transverse Section, at the Site of the Shoulders, of the Thorax of the Horse
+(Diagrammatic Figure)</span></td>
+<td class="right bot">24</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig015">15.</a></td>
+<td class="just top"><span class="smcap">Vertical and Transverse Section, at the Plane of the Shoulders, of the Thorax of the Dog
+(Diagrammatic Figure)</span></td>
+<td class="right bot">24</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig016">16.</a></td>
+<td class="just top"><span class="smcap">Left Clavicle of the Cat: Superior Surface (Natural Size)</span></td>
+<td class="right bot">26</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig017">17.</a></td>
+<td class="just top"><span class="smcap">Clavicle of the Dog (Natural Size)</span></td>
+<td class="right bot">26</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig018">18.</a></td>
+<td class="just top"><span class="smcap">Skeleton of the Shoulder of a Bird (Vulture): Antero-External View of the Left Side</span></td>
+<td class="right bot">27</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig019">19.</a></td>
+<td class="just top"><span class="smcap">Inferior Extremity of the Left Humerus of a Felid&aelig; (Lion)</span></td>
+<td class="right bot">31</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig020">20.</a></td>
+<td class="just top"><span class="smcap">Inferior Extremity of the Left Human Humerus, showing the Presence of a Supratrochlear
+Process</span></td>
+<td class="right bot">31</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig021">21.</a></td>
+<td class="just top"><span class="smcap">Skeleton of a Bird (Vulture): Left Surface</span></td>
+<td class="right bot">33</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig022">22.</a></td>
+<td class="just top"><span class="smcap">The Human Hand resting for its Whole Extent on its Palmar Surface: Left Side, External
+Surface</span></td>
+<td class="right bot">35</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig023">23.</a></td>
+<td class="just top"><span class="smcap">The Human Hand resting on its Phalanges: Left Side, External Surface</span></td>
+<td class="right bot">36</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig024">24.</a></td>
+<td class="just top"><span class="smcap">The Human Hand resting on the Tips of some of its Third Phalanges: Left Side, External
+View</span></td>
+<td class="right bot">36</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig025">25.</a></td>
+<td class="just top"><span class="smcap">Superior Extremity of the Bones of the Human Forearm: Left Side, Superior Surface</span></td>
+<td class="right bot">39</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig026">26.</a></td>
+<td class="just top"><span class="smcap">Superior Extremity of the Bones of the Forearm of a Dog: Left Limb, Superior Surface</span></td>
+<td class="right bot">39</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig027">27.</a></td>
+<td class="just top"><span class="smcap">Superior Extremity of the Bones of the Forearm of the Horse: Left Limb, Superior
+Surface</span></td>
+<td class="right bot">40</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig028">28.</a></td>
+<td class="just top"><span class="smcap">Inferior Extremity of the Bones of the Forearm of a Man: Left Side, Posterior Surface, Position
+of Supination</span></td>
+<td class="right bot">41</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig029">29.</a></td>
+<td class="just top"><span class="smcap">Inferior Extremity of the Bones of the Forearm of a Dog: Left Side, Anterior Surface, Normal
+Position&mdash;that is, the Position of Pronation</span></td>
+<td class="right bot">41</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig030">30.</a></td>
+<td class="just top"><span class="smcap">Inferior Extremity of the Bone of the Forearm of the Horse: Left Side, Anterior
+Surface</span></td>
+<td class="right bot">42</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig031">31.</a></td>
+<td class="just top"><span class="smcap">Skeleton of the Superior Limb of a Bird (Vulture): Left Side, External Surface</span></td>
+<td class="right bot">47</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig032">32.</a></td>
+<td class="just top"><span class="smcap">Superior Limb of the Human Being, the Different Segments being placed in the Attitude which the
+Corresponding Parts occupy in Birds: Left Side, External Surface</span></td>
+<td class="right bot">48</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig033">33.</a></td>
+<td class="just top"><span class="smcap">Skeleton of the Bear: Left Lateral Surface</span></td>
+<td class="right bot">50</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig034">34.</a></td>
+<td class="just top"><span class="smcap">Skeleton of the Dog: Left Lateral Surface</span></td>
+<td class="right bot">52</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig035">35.</a></td>
+<td class="just top"><span class="smcap">Scapula of the Dog: Left Side, External Surface</span></td>
+<td class="right bot">53</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig036">36.</a></td>
+<td class="just top"><span class="smcap">Left Scapula of the Cat: External Surface</span></td>
+<td class="right bot">53</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig037">37.</a></td>
+<td class="just top"><span class="smcap">Skeleton of the Finger of a Felide (Lion): Left Side, Internal Surface</span></td>
+<td class="right bot">57</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig038">38.</a><span class="pagenum"><a name="Page_xvii" id="Page_xvii">[xvii]</a></span></td>
+<td class="just top"><span class="smcap">Skeleton of the Pig: Left Lateral Surface</span></td>
+<td class="right bot">58</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig039">39.</a></td>
+<td class="just top"><span class="smcap">Skeleton of the Ox: Left Lateral Surface</span></td>
+<td class="right bot">61</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig040">40.</a></td>
+<td class="just top"><span class="smcap">Skeleton of the Horse: Left Lateral Surface</span></td>
+<td class="right bot">64</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig041">41.</a></td>
+<td class="just top"><span class="smcap">Flexion of the Humerus: Right Anterior Limb of the Horse, External Surface (after a
+Chromophotographic Study by Professor Marey)</span></td>
+<td class="right bot">74</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig042">42.</a></td>
+<td class="just top"><span class="smcap">Extension of the Humerus: Right Anterior Limb of the Horse, External Surface (after a
+Chromophotographic Study by Professor Marey)</span></td>
+<td class="right bot">74</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig043">43.</a></td>
+<td class="just top"><span class="smcap">The Left Iliac Bone of the Human Being: External Surface, placed in the Position which it would
+occupy in the Skeleton of a Quadruped</span></td>
+<td class="right bot">79</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig044">44.</a></td>
+<td class="just top"><span class="smcap">Left Iliac Bone of a Quadruped (Horse): External Surface</span></td>
+<td class="right bot">79</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig045">45.</a></td>
+<td class="just top"><span class="smcap">Pubic Region of the Pelvis of a Marsupial (Phalanger, Fox</span>)</td>
+<td class="right bot">81</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig046">46.</a></td>
+<td class="just top"><span class="smcap">Pelvis of a Bird (the Cock): External Surface, Left Side</span></td>
+<td class="right bot">82</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig047">47.</a></td>
+<td class="just top"><span class="smcap">Posterior Limb of the Horse placed in the Position which it should occupy if the Animal Were a
+Plantigrade: Left Limb, External Surface</span></td>
+<td class="right bot">89</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig048">48.</a></td>
+<td class="just top"><span class="smcap">Skeleton of the Foot of a Bird (the Cock): Left Side, External Surface</span></td>
+<td class="right bot">90</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig049">49.</a></td>
+<td class="just top"><span class="smcap">Pelvis of the Dog, seen from Above</span></td>
+<td class="right bot">91</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig050">50.</a></td>
+<td class="just top"><span class="smcap">Pelvis of a Felide (Lion), viewed from Above</span></td>
+<td class="right bot">92</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig051">51.</a></td>
+<td class="just top"><span class="smcap">Pelvis of the Ox: Superior Surface</span></td>
+<td class="right bot">95</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig052">52.</a></td>
+<td class="just top"><span class="smcap">Tarsus of the Ox: Posterior Left Limb, Antero-external Surface</span></td>
+<td class="right bot">97</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig053">53.</a></td>
+<td class="just top"><span class="smcap">Pelvis of the Horse: Superior Surface</span></td>
+<td class="right bot">101</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig054">54.</a></td>
+<td class="just top"><span class="smcap">Tarsus of the Horse: Left Posterior Limb, Anterior Surface</span></td>
+<td class="right bot">104</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig055">55.</a></td>
+<td class="just top"><span class="smcap">Extension of the Leg: Right Posterior Limb of the Horse, External Surface (after a Chronographic
+Study by Professor Marey)</span></td>
+<td class="right bot">107</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig056">56.</a></td>
+<td class="just top"><span class="smcap">Human Skull: Measure of the Facial Angle by the Method of Camper. Angle BAC = 80&deg;</span></td>
+<td class="right bot">110</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig057">57.</a></td>
+<td class="just top"><span class="smcap">Skull of the Horse: Measure of the Facial Angle by the Method of Camper. Angle BAC =
+13&deg;</span></td>
+<td class="right bot">110</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig058">58.</a></td>
+<td class="just top"><span class="smcap">Skull of one of the Felid&aelig; (Jaguar): Left Lateral Aspect</span></td>
+<td class="right bot">113</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig059">59.</a></td>
+<td class="just top"><span class="smcap">Skull of the Lion: Left Lateral Aspect</span></td>
+<td class="right bot">113</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig060">60.</a></td>
+<td class="just top"><span class="smcap">Skull of the Dog: Left Lateral Aspect</span></td>
+<td class="right bot">115</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig061">61.</a></td>
+<td class="just top"><span class="smcap">Skull of the Pig: Left Lateral Aspect</span></td>
+<td class="right bot">117</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig062">62.</a></td>
+<td class="just top"><span class="smcap">Skull of the Ox: Left Lateral Aspect</span></td>
+<td class="right bot">119</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig063">63.</a></td>
+<td class="just top"><span class="smcap">Skull of the Horse: Left Lateral Aspect</span></td>
+<td class="right bot">121</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig064">64.</a></td>
+<td class="just top"><span class="smcap">Skull of the Hare: Left Lateral Aspect</span></td>
+<td class="right bot">123</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig065">65.</a></td>
+<td class="just top"><span class="smcap">Skull of the Cock: Left Lateral Surface</span></td>
+<td class="right bot">128</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig066">66.</a></td>
+<td class="just top"><span class="smcap">Myology of the Horse: Anterior Aspect of the Trunk</span></td>
+<td class="right bot">132</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig067">67.</a><span class="pagenum"><a name="Page_xviii" id="Page_xviii">[xviii]</a></span></td>
+<td class="just top"><span class="smcap">Myology of the Horse: Inferior Aspect of the Trunk</span></td>
+<td class="right bot">135</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig068">68.</a></td>
+<td class="just top"><span class="smcap">Myology of the Dog: Superficial Layer of Muscles</span></td>
+<td class="right bot">141</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig069">69.</a></td>
+<td class="just top"><span class="smcap">Myology of the Ox: Superficial Layer of Muscles</span></td>
+<td class="right bot">143</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig070">70.</a></td>
+<td class="just top"><span class="smcap">Myology of the Horse: Superficial Layer of Muscles</span></td>
+<td class="right bot">146</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig071">71.</a></td>
+<td class="just top"><span class="smcap">Myology of the Horse: Panniculus Muscle of the Trunk</span></td>
+<td class="right bot">148</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig072">72.</a></td>
+<td class="just top"><span class="smcap">Myology of the Horse&mdash;Shoulder and Arm: Left Side, External Surface</span></td>
+<td class="right bot">166</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig073">73.</a></td>
+<td class="just top"><span class="smcap">Myology of the Dog: Left Anterior Limb, External Aspect</span></td>
+<td class="right bot">178</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig074">74.</a></td>
+<td class="just top"><span class="smcap">Myology of the Ox: Left Anterior Limb, External Aspect</span></td>
+<td class="right bot">180</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig075">75.</a></td>
+<td class="just top"><span class="smcap">Myology of the Horse: Left Anterior Limb, External Aspect</span></td>
+<td class="right bot">182</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig076">76.</a></td>
+<td class="just top"><span class="smcap">Myology of the Dog: Left Anterior Limb, Internal Aspect</span></td>
+<td class="right bot">190</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig077">77.</a></td>
+<td class="just top"><span class="smcap">Myology of the Horse: Anterior Limb, Left Side, Internal Aspect</span></td>
+<td class="right bot">192</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig078">78.</a></td>
+<td class="just top"><span class="smcap">Left Anterior Limb of the Horse: Internal Aspect</span></td>
+<td class="right bot">194</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig079">79.</a></td>
+<td class="just top"><span class="smcap">Left Anterior Limb of the Horse: External Aspect</span></td>
+<td class="right bot">196</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig080">80.</a></td>
+<td class="just top"><span class="smcap">Left Anterior Limb of the Horse: External Aspect</span></td>
+<td class="right bot">196</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig081">81.</a></td>
+<td class="just top"><span class="smcap">Diagram of the Posterior Part of a Transverse Section passing through the Middle of the Left
+Fore-limb of the Dog: Surface of the Inferior Segment of the Section</span></td>
+<td class="right bot">198</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig082">82.</a></td>
+<td class="just top"><span class="smcap">Diagram of a Horizontal Section of the Middle of the Forearm of the Left Leg of the Horse:
+Surface of the Interior Segment of the Section</span></td>
+<td class="right bot">198</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig083">83.</a></td>
+<td class="just top"><span class="smcap">Myology of the Horse: the Anterior Tibial Muscle (Flexor of the Metatarsus), Left Leg, Anterior
+View</span></td>
+<td class="right bot">214</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig084">84.</a></td>
+<td class="just top"><span class="smcap">Myology of the Dog: Left Hind-limb, External Aspect</span></td>
+<td class="right bot">216</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig085">85.</a></td>
+<td class="just top"><span class="smcap">Myology of the Ox: Left Leg, External Aspect</span></td>
+<td class="right bot">218</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig086">86.</a></td>
+<td class="just top"><span class="smcap">Myology of the Horse: Left Hind-limb, External Aspect</span></td>
+<td class="right bot">220</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig087">87.</a></td>
+<td class="just top"><span class="smcap">Myology of the Dog: Left Hind-limb, Internal Aspect</span></td>
+<td class="right bot">222</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig088">88.</a></td>
+<td class="just top"><span class="smcap">Myology of the Horse: Left Hind-leg, Internal Aspect</span></td>
+<td class="right bot">223</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig089">89.</a></td>
+<td class="just top"><span class="smcap">Myology of the Dog: Masticatory Muscles (a Deeper Dissection than that shown in Fig.
+90)</span></td>
+<td class="right bot">233</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig090">90.</a></td>
+<td class="just top"><span class="smcap">Myology of the Dog: Muscles of the Head</span></td>
+<td class="right bot">235</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig091">91.</a></td>
+<td class="just top"><span class="smcap">Myology of the Ox: Muscles of the Head</span></td>
+<td class="right bot">237</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig092">92.</a></td>
+<td class="just top"><span class="smcap">Myology of the Horse: Muscles of the Head</span></td>
+<td class="right bot">239</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig093">93.</a></td>
+<td class="just top"><span class="smcap">Claw of the Dog: Inferior Surface</span></td>
+<td class="right bot">249</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig094">94.</a></td>
+<td class="just top"><span class="smcap">Left Hand of the Dog: Inferior Surface, Plantar Tubercles</span></td>
+<td class="right bot">249</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig095">95.</a><span class="pagenum"><a name="Page_xix" id="Page_xix">[xix]</a></span></td>
+<td class="just top"><span class="smcap">Vertical Antero-posterior Section of the Foot of a Horse</span></td>
+<td class="right bot">250</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig096">96.</a></td>
+<td class="just top"><span class="smcap">Third Phalanx of the Horse: Left Anterior Limb, External Surface</span></td>
+<td class="right bot">251</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig097">97.</a></td>
+<td class="just top"><span class="smcap">Left Anterior Foot of the Horse: Anterior Aspect</span></td>
+<td class="right bot">253</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig098">98.</a></td>
+<td class="just top"><span class="smcap">Left Anterior Foot of the Horse: External Aspect</span></td>
+<td class="right bot">254</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig099">99.</a></td>
+<td class="just top"><span class="smcap">Vertical and Transverse Section of a Left Human Foot: Outline of the Surface of the Posterior
+Segment of this Section (Diagrammatic Figure)</span></td>
+<td class="right bot">255</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig100">100.</a></td>
+<td class="just top"><span class="smcap">Inferior Surface of a Fore-hoof of the Horse: Left Side</span></td>
+<td class="right bot">256</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig101">101.</a></td>
+<td class="just top"><span class="smcap">Third Phalanx of the Horse: Left Anterior Limb, Inferior View</span></td>
+<td class="right bot">257</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig102">102.</a></td>
+<td class="just top"><span class="smcap">Third Phalanx of the Horse: Left Posterior Limb, Inferior View</span></td>
+<td class="right bot">257</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig103">103.</a></td>
+<td class="just top"><span class="smcap">Inferior Surface of a Hind-hoof of a Horse: Left Side</span></td>
+<td class="right bot">258</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig104">104.</a></td>
+<td class="just top"><span class="smcap">Left Posterior Foot of a Horse: External Aspect</span></td>
+<td class="right bot">259</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig105">105.</a></td>
+<td class="just top"><span class="smcap">Foot of the Ox: Left Side, Antero-external View</span></td>
+<td class="right bot">260</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig106">106.</a></td>
+<td class="just top"><span class="smcap">The Proportions of the Horse (after Bourgelat)</span></td>
+<td class="right bot">265</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig107">107.</a></td>
+<td class="just top"><span class="smcap">Proportions of the Horse (after Colonel Duhousset)</span></td>
+<td class="right bot">270</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig108">108.</a></td>
+<td class="just top"><span class="smcap">Proportions of the Head of the Horse, viewed in Profile (after Colonel Duhousset)</span></td>
+<td class="right bot">274</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig109">109.</a></td>
+<td class="just top"><span class="smcap">The Same Design as that of Fig. 108, on which we have indicated, by Similar Lines, the Principal
+Corresponding Measurements</span></td>
+<td class="right bot">275</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig110">110.</a></td>
+<td class="just top"><span class="smcap">Proportions of the Head of the Horse, seen from the Front (after Colonel Duhousset)</span></td>
+<td class="right bot">276</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig111">111.</a></td>
+<td class="just top"><span class="smcap">The Same Figure as Fig. 110, on which we have marked, by Similar Lines, the Principal
+Measurements which correspond thereto</span></td>
+<td class="right bot">277</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig112">112.</a></td>
+<td class="just top"><span class="smcap">Horse of which the Length contains more than Two and a Half Times that of the Head, and of which
+this Dimension (A, B) exceeds the Height</span></td>
+<td class="right bot">279</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig113">113.</a></td>
+<td class="just top"><span class="smcap">Horse of which the Length contains more than Two and a Half Times that of the Head, and of which
+this Dimension (A, B) exceeds the Height</span></td>
+<td class="right bot">280</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig114">114.</a></td>
+<td class="just top"><span class="smcap">Horse of which the Length contains more than Two and a Half Times that of the Head, and of which
+this Dimension (A, B) is Inferior to the Height</span></td>
+<td class="right bot">281</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig115">115.</a></td>
+<td class="just top"><span class="smcap">Experimental Shoes, intended to Record the Pressure of the Foot on the Ground</span></td>
+<td class="right bot">284</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig116">116.</a></td>
+<td class="just top"><span class="smcap">Runner furnished with the Exploratory and Registering Apparatus of the Various Paces</span></td>
+<td class="right bot">285</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig117">117.</a></td>
+<td class="just top"><span class="smcap">Tracing of the Running of a Man (after Professor Marey)</span></td>
+<td class="right bot">286</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig118">118.</a><span class="pagenum"><a name="Page_xx" id="Page_xx">[xx]</a></span></td>
+<td class="just top"><span class="smcap">Notation of a Tracing of the Running of a Man (after Professor Marey)</span></td>
+<td class="right bot">287</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig119">119.</a></td>
+<td class="just top"><span class="smcap">Notation of Various Modes of Progression of a Man (after Professor Marey)</span></td>
+<td class="right bot">287</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig120">120.</a></td>
+<td class="just top"><span class="smcap">Swing of the Raised Anterior Limb (after G. Colin)</span></td>
+<td class="right bot">289</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig121">121.</a></td>
+<td class="just top"><span class="smcap">Swing of the Anterior Limb on the Point of Pressure (after G. Colin)</span></td>
+<td class="right bot">290</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig122">122.</a></td>
+<td class="just top"><span class="smcap">Posterior Limb, giving the Impulse (after G. Colin)</span></td>
+<td class="right bot">291</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig123">123.</a></td>
+<td class="just top"><span class="smcap">Notation of the Ambling Gait in the Horse (after Professor Marey)</span></td>
+<td class="right bot">292</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig124">124.</a></td>
+<td class="just top"><span class="smcap">The Amble: Right Lateral Pressure</span></td>
+<td class="right bot">293</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig125">125.</a></td>
+<td class="just top"><span class="smcap">Notation of the Gait of the Trot in a Horse (after Professor Marey)</span></td>
+<td class="right bot">294</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig126">126.</a></td>
+<td class="just top"><span class="smcap">The Trot: Right Diagonal Pressure</span></td>
+<td class="right bot">295</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig127">127.</a></td>
+<td class="just top"><span class="smcap">The Trot: Time of Suspension</span></td>
+<td class="right bot">295</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig128">128.</a></td>
+<td class="just top"><span class="smcap">Notation of the Pace of Stepping in the Horse (after Professor Marey)</span></td>
+<td class="right bot">296</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig129">129.</a></td>
+<td class="just top"><span class="smcap">The Step: Right Lateral Pressure</span></td>
+<td class="right bot">297</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig130">130.</a></td>
+<td class="just top"><span class="smcap">The Step: Right Diagonal Pressure</span></td>
+<td class="right bot">297</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig131">131.</a></td>
+<td class="just top"><span class="smcap">The Gallop: First Period</span></td>
+<td class="right bot">298</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig132">132.</a></td>
+<td class="just top"><span class="smcap">The Gallop: Second Period</span></td>
+<td class="right bot">298</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig133">133.</a></td>
+<td class="just top"><span class="smcap">The Gallop: Third Period</span></td>
+<td class="right bot">299</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig134">134.</a></td>
+<td class="just top"><span class="smcap">The Gallop: Time of Suspension</span></td>
+<td class="right bot">299</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig135">135.</a></td>
+<td class="just top"><span class="smcap">Notation of the Gallop divided into Three Periods of Time (after Professor Marey)</span></td>
+<td class="right bot">300</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig136">136.</a></td>
+<td class="just top"><span class="smcap">Notation of the Gallop of Four Periods in the Horse (after Professor Marey)</span></td>
+<td class="right bot">300</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig137">137.</a></td>
+<td class="just top"><span class="smcap">Leap of the Hare (after G. Colin)</span></td>
+<td class="right bot">301</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig138">138.</a></td>
+<td class="just top"><span class="smcap">The Leap</span></td>
+<td class="right bot">302</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig139">139.</a></td>
+<td class="just top"><span class="smcap">The Leap</span></td>
+<td class="right bot">302</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig140">140.</a></td>
+<td class="just top"><span class="smcap">The Leap</span></td>
+<td class="right bot">303</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig141">141.</a></td>
+<td class="just top"><span class="smcap">The Leap</span></td>
+<td class="right bot">303</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig142">142.</a></td>
+<td class="just top"><span class="smcap">The Leap</span></td>
+<td class="right bot">305</td>
+</tr>
+
+<tr>
+<td class="right top padr1"><a href="#Fig143">143.</a></td>
+<td class="just top"><span class="smcap">The Leap</span></td>
+<td class="right bot">305</td>
+</tr>
+
+</table>
+
+<hr class="c25" />
+<p class="pagenum"><a name="Page_1" id="Page_1">[1]</a></p>
+<h2 style="margin-bottom: 2em; font-size: 175%;">THE ARTISTIC ANATOMY OF ANIMALS</h2>
+
+<h2>INTRODUCTION</h2>
+
+<h3>GENERALITIES OF COMPARATIVE ANATOMY</h3>
+
+<p>Of the animals by which we are surrounded, there are some
+which, occupying a place in our lives by reason of their
+natural endowments, are frequently represented in the works
+of artists&mdash;either as accompanying man in his work or in
+his amusements, or as intended to occupy the whole interest
+of the composition.</p>
+
+<p>The necessity of knowing, from an artistic point of view,
+the structure of the human body makes clear the importance
+we attach, from the same point of view, to the study of the
+anatomy of animals&mdash;that is, the study of comparative
+anatomy. The name employed to designate this branch of
+anatomy shows that the object of this science is the study
+of the relative position and form which each region presents
+in all organized beings, taking for comparison the corresponding
+regions in man. The head in animals compared with
+the human head; the trunk and limbs compared to the
+trunk and limbs of the human being&mdash;this is the analysis we
+undertake, and the plan of the subject we are about to
+commence.</p>
+
+<p>Our intention being, as we have just said, the comparison
+of the structure of animals with that of man, should we
+describe the anatomy of the human being in the pages<span class="pagenum"><a name="Page_2" id="Page_2">[2]</a></span>
+which follow? We do not think so. Plastic human
+anatomy having been previously studied in special works,<a name="FNanchor_2_2" id="FNanchor_2_2"></a><a
+href="#Footnote_2_2" class="fnanchor">[2]</a>
+we take it for granted that these have been studied before
+undertaking the subject of comparative anatomy. We
+will therefore not occupy time with the elementary facts
+relative to the skeleton and the superficial layer of muscles.
+We will not dilate on the division of the bones into long,
+short, large, single, paired, etc. All these preliminary
+elements we shall suppose to have been already studied.</p>
+
+<p>This being granted, it is, nevertheless, necessary to take
+a rapid bird&#8217;s-eye view of organized beings, and to recall the
+terms used in their classification.</p>
+
+<p>Animals are primarily classed in great divisions, based
+on the general characters which differentiate them most.
+These divisions, or <i>branches</i>, allow of their being so grouped
+that in each of them we find united the individuals whose
+general structure is uniform; and under the name of vertebrates
+are included man and the animals with which our
+studies will be occupied. The vertebrates, as the name
+indicates, are recognised by the presence of an interior
+skeleton formed by a central axis, the vertebral column,
+round which the other parts of the skeleton are arranged.</p>
+
+<p>The vertebrate branch is divided into classes: fishes,
+amphibians or batrachians, reptiles, birds, and mammals.</p>
+
+<p>The mammals&mdash;from the Latin <i>mamma</i>, a breast&mdash;are
+characterized by the presence of breasts designed for the
+alimentation of their young. Their bodies are covered with
+hair, hence the name <i>pilif&egrave;res</i> proposed by Blainville; and,
+notwithstanding that in some individuals the hairs are few,
+the character is sufficient to distinguish them from all other
+vertebrates.</p>
+
+<p>We find united in this class animals which, at first, seem
+out of place, such as the whale and the bat; and, from their
+external appearance alone, the former would appear to<span class="pagenum"><a name="Page_3" id="Page_3">[3]</a></span>
+belong to the fishes, and the latter to birds. Yet, on studying
+their structure, we find that, not only do these animals
+merit a place in the class which they occupy, because they
+possess the distinctive characters of mammals; but, still
+further, their internal structure is analogous to that of man
+and of the other individuals of this class.</p>
+
+<p>Notwithstanding this similarity of structure, the whale
+is not without some points of difference from its neighbours
+the horse and the dog; therefore, in order to place each of
+these animals in a position suitable to it, mammals are
+divided into secondary groups called <i>orders</i>. The first of
+these orders includes, under the name <i>primates</i>, man and
+apes. The latter contain animals which approach birds in
+certain characters of their organism, forming a link between
+the latter and mammals.</p>
+
+<p>We find, in studying the regions of the body in some of the
+vertebrates, that, while they present differences from the
+corresponding regions of the human body, they also offer
+most striking analogies. We can, for example, recognise
+the upper limb of man in the anterior one of quadrupeds,
+in the wing of the bat, in the paddle of the seal, etc. It is,
+so to speak, those variations of a great plan which give
+such a charm to the study of comparative anatomy.</p>
+
+<p>The division of classes into orders, which we have just
+mentioned, being still too general, it was found necessary to
+establish subdivisions&mdash;more and more specialized&mdash;to
+which the names <i>families</i>, <i>genera</i>, <i>species</i>, and <i>varieties</i> were
+given.</p>
+
+<div class="footnote">
+<p><a name="Footnote_2_2" id="Footnote_2_2"></a><a href="#FNanchor_2_2"><span class="label">[2]</span></a> Mathias Duval,
+&#8216;Pr&eacute;cis of Anatomy for the Use of Artists&#8217;: Paris,
+1881. &#8216;Artistic Anatomy of the Human Body,&#8217; third edition, plates by
+Dr. Fau, text with figures by &Eacute;douard Cuyer: Paris, 1896. &#8216;Artistic
+Anatomy of Man,&#8217; by J. C. L. Sparkes, second edition, text with 50 plates:
+Bailli&egrave;re, Tindall and Cox, London, 1900.</p>
+</div>
+
+<hr class="c25" />
+<p class="pagenum"><a name="Page_4" id="Page_4">[4]</a></p>
+<h2>CHAPTER I</h2>
+
+<h3>OSTEOLOGY AND ARTHROLOGY</h3>
+
+<h4>THE TRUNK</h4>
+
+<h5>The Vertebral Column</h5>
+
+<p>We commence the study of the skeleton with a description
+of the trunk.</p>
+
+<div class="figmed"><a name="Fig001" id="Fig001"></a>
+<img src="images/illo026.png" alt="Fig. 1" width="500" height="361" />
+<p class="caption just">Fig. 1.&mdash;A Human Skeleton in the Attitude of a Quadruped. To
+give a general Idea of the position of the Bones in other
+Vertebrates.</p></div>
+
+<p>The trunk being, in quadrupeds, horizontal in direction
+(<a href="#Fig001">Fig. 1</a>), the two regions of which it consists occupy, for this
+reason, the following positions: the thorax occupies the
+anterior part, the abdomen is placed behind it; the vertebral
+column is horizontal, and is situated at the superior aspect
+of the trunk; it projects beyond the latter: anteriorly, to
+articulate with the skull; and, posteriorly, to form the
+skeleton of the tail, or caudal appendix.</p>
+
+<p>The number of the vertebr&aelig; is not the same in all mammalia.
+Of the several regions of the vertebral column, the
+cervical shows the greatest uniformity in the number of the
+vertebr&aelig; of which it consists, with but two exceptions
+(eight or nine in the three-toed sloth, and six in the manatee);
+we always find seven cervical vertebr&aelig;, whatever the length
+of the neck of the animal. There are no more than seven
+vertebr&aelig; in the long neck of the giraffe, but they are very
+long ones; and not less than seven in the very short neck
+of the dolphin, in which they are reduced to mere plates of
+bone not thicker than sheets of cardboard. If the cervical
+region presents uniformity in the number of its bones, it is
+not so with the other regions of the column.</p>
+
+<p><span class="pagenum"><a name="Page_5" id="Page_5">[5]</a></span>The following table shows their classification in some
+animals:</p>
+
+<h6><span class="smcap">Vertebr&aelig;.</span></h6>
+
+<table class="fsize80" summary="Table page 5">
+
+<tr class="bt bb">
+<td class="bl br">&nbsp;</td>
+<td class="center padl1 padr1 br">Cervical.</td>
+<td class="center padl1 padr1 br">Dorsal.</td>
+<td class="center padl1 padr1 br">Lumbar.</td>
+</tr>
+
+<tr>
+<td class="left padl1 padr1 bl br">Bear</td>
+<td class="center br">7</td>
+<td class="center br">14</td>
+<td class="center br">6</td>
+</tr>
+
+<tr>
+<td class="left padl1 padr1 bl br">Dog</td>
+<td class="center br">7</td>
+<td class="center br">13</td>
+<td class="center br">7</td>
+</tr>
+
+<tr>
+<td class="left padl1 padr1 bl br">Cat</td>
+<td class="center br">7</td>
+<td class="center br">13</td>
+<td class="center br">7</td>
+</tr>
+
+<tr>
+<td class="left padl1 padr1 bl br">Rabbit</td>
+<td class="center br">7</td>
+<td class="center br">12</td>
+<td class="center br">7</td>
+</tr>
+
+<tr>
+<td class="left padl1 padr1 bl br">Pig</td>
+<td class="center br">7</td>
+<td class="center br">14</td>
+<td class="center br">6 or 7</td>
+</tr>
+
+<tr>
+<td class="left padl1 padr1 bl br">Horse</td>
+<td class="center br">7</td>
+<td class="center br">18</td>
+<td class="center br">6 or 5</td>
+</tr>
+
+<tr>
+<td class="left padl1 padr1 bl br">Ass</td>
+<td class="center br">7</td>
+<td class="center br">18</td>
+<td class="center br">5</td>
+</tr>
+
+<tr>
+<td class="left padl1 padr1 bl br">Camel</td>
+<td class="center br">7</td>
+<td class="center br">12</td>
+<td class="center br">7</td>
+</tr>
+
+<tr>
+<td class="left padl1 padr1 bl br">Giraffe</td>
+<td class="center br">7</td>
+<td class="center br">14</td>
+<td class="center br">5</td>
+</tr>
+
+<tr>
+<td class="left padl1 padr1 bl br">Ox</td>
+<td class="center br">7</td>
+<td class="center br">13</td>
+<td class="center br">6</td>
+</tr>
+
+<tr class="bb">
+<td class="left padl1 padr1 bl br">Sheep</td>
+<td class="center br">7</td>
+<td class="center br">13</td>
+<td class="center br">6</td>
+</tr>
+
+</table>
+
+<p>It is worthy of notice that in birds the number of the
+cervical vertebr&aelig; is not constant, as in mammals; they are<span class="pagenum"><a name="Page_6" id="Page_6">[6]</a></span>
+more numerous than the dorsal. These latter are almost
+always joined to one another by a fusion of their spinous
+processes; the two or three last vertebr&aelig; are similarly
+united to the iliac bones, between which they are fixed. The
+dorsal vertebr&aelig; thus form one piece, which gives solidity to
+the trunk, and provides a base of support to the wings,
+for the movements of flying. There are, so to speak, no
+lumbar vertebr&aelig;, the bones of that region, which cannot be
+differentiated from the sacrum, having coalesced with the
+bones of the pelvis.</p>
+
+<h6><span class="smcap">Vertebr&aelig;.</span></h6>
+
+<table class="fsize80" summary="Table page 6-1">
+
+<tr class="bt bb">
+<td class="center padl1 padr1 bl br">&nbsp;</td>
+<td class="center padl1 padr1 br">Cervical.</td>
+<td class="center padl1 padr1 br">Dorsal.</td>
+</tr>
+
+<tr>
+<td class="left padl1 padr1 bl br">Vulture</td>
+<td class="center br">15</td>
+<td class="center br">7</td>
+</tr>
+
+<tr>
+<td class="left padl1 padr1 bl br">Eagle</td>
+<td class="center br">13</td>
+<td class="center br">9</td>
+</tr>
+
+<tr>
+<td class="left padl1 padr1 bl br">Cock</td>
+<td class="center br">14</td>
+<td class="center br">7</td>
+</tr>
+
+<tr>
+<td class="left padl1 padr1 bl br">Ostrich</td>
+<td class="center br">18</td>
+<td class="center br">9</td>
+</tr>
+
+<tr>
+<td class="left padl1 padr1 bl br">Swan</td>
+<td class="center br">23</td>
+<td class="center br">10</td>
+</tr>
+
+<tr>
+<td class="left padl1 padr1 bl br">Goose</td>
+<td class="center br">18</td>
+<td class="center br">9</td>
+</tr>
+
+<tr class="bb">
+<td class="left padl1 padr1 bl br">Duck</td>
+<td class="center br">15</td>
+<td class="center br">9</td>
+</tr>
+
+</table>
+
+<p>In reptiles, the relation between the number of the cervical
+vertebr&aelig; and that of the dorsal is very variable; some
+serpents are devoid of cervical vertebr&aelig;, having only dorsal
+ones&mdash;that is, vertebr&aelig; carrying well-developed ribs.</p>
+
+<h6><span class="smcap">Vertebr&aelig;.</span></h6>
+
+<table class="fsize80" summary="Table page 6-2">
+
+<tr class="bt bb">
+<td class="bl br">&nbsp;</td>
+<td class="center padl1 padr1 br">Cervical.</td>
+<td class="center padl1 padr1 br">Dorsal.</td>
+<td class="center padl1 padr1 br">Lumbar.</td>
+</tr>
+
+<tr>
+<td class="left padl1 padr1 bl br">Crocodile</td>
+<td class="center br">7</td>
+<td class="right padr3 br">14</td>
+<td class="center br">3</td>
+</tr>
+
+<tr>
+<td class="left padl1 padr1 bl br">Caiman</td>
+<td class="center br">7</td>
+<td class="right padr3 br">12</td>
+<td class="center br">5</td>
+</tr>
+
+<tr>
+<td class="left padl1 padr1 bl br">Boa</td>
+<td class="center br">3</td>
+<td class="right padr3 br">248</td>
+<td class="center br">0</td>
+</tr>
+
+<tr>
+<td class="left padl1 padr1 bl br">Python</td>
+<td class="center br">0</td>
+<td class="right padr3 br">320</td>
+<td class="center br">0</td>
+</tr>
+
+<tr class="bb">
+<td class="left padl1 padr1 bl br">Viper</td>
+<td class="center br">2</td>
+<td class="right padr3 br">145</td>
+<td class="center br">0</td>
+</tr>
+
+</table>
+
+<div class="figmed"><a name="Fig002" id="Fig002"></a>
+<img src="images/illo028.png" alt="Fig. 2" width="350" height="365" />
+<p class="caption just">Fig. 2.&mdash;Size of the Atlas compared with the Transverse Dimensions
+of the Corresponding Parts of the Skull in Man.</p>
+
+<p class="subcaption just">1, Atlas; 2, mastoid process; 3, external occipital protuberance;
+4, inferior maxilla.</p></div>
+
+<p>Regarding the direction of the vertebral column in animals,
+in which the trunk is not vertical, it is evident that the
+spinous processes point upward, and that in comparing them
+with those of man they must be arranged so that the superior
+surface of the human vertebra will correspond to the anterior<span class="pagenum"><a name="Page_7" id="Page_7">[7]</a></span>
+surface of that of the quadruped. Of the cervical vertebr&aelig;,
+the atlas and axis call for special notice. Apropos of the
+atlas, we find that it, in the human being, is narrower than
+the corresponding parts of the skull, and is therefore hidden
+under the base of the cranium (<a href="#Fig002">Fig. 2</a>); in quadrupeds its
+width is equal to that of the skull, and sometimes exceeds,
+because of the great development of its wing-shaped transverse
+processes, that of the neighbouring parts of the head
+(<a href="#Fig003">Fig. 3</a>). On this account those transverse processes often
+project under the skin of the lateral surfaces of the upper
+part of the neck.</p>
+
+<div class="figmed"><a name="Fig003" id="Fig003"></a>
+<img src="images/illo029.png" alt="Fig. 3" width="350" height="401" />
+<p class="caption just">Fig. 3.&mdash;Size of the Atlas compared with the Transverse Dimensions
+of the corresponding Regions of the Skull in a Dog.</p>
+
+<p class="subcaption just">1, Atlas; 2, zygomatic arch; 3, external occipital protuberance; 4,
+inferior maxilla.</p></div>
+
+<p>The axis is furnished on its anterior surface with the odontoid
+process, which articulates with the anterior (or inferior)
+arch of the atlas, according to the direction of the neck.
+The spinous process, flattened from without inwards, is
+more or less pointed; it is elongated from before backwards,
+so as partly to overlap the atlas and the third cervical
+vertebra.</p>
+
+<p>We find that this process overlaps less and less the neighbouring
+vertebr&aelig; when we examine in succession the bear,
+the cat, the dog, the ox, and the horse. With regard to the
+other vertebr&aelig; of this region, they diminish in width from<span class="pagenum"><a name="Page_8" id="Page_8">[8]</a></span>
+the second to the seventh; and, in some animals, the anterior
+surface of the body presents a tubercle which articulates
+with a cavity hollowed in the posterior surface of that
+of the vertebra before it; this feature dwindles away in the
+dorsal and lumbar regions.</p>
+
+<p>The spinous process, slightly developed in the third
+cervical vertebra, gradually increases in size to the seventh,
+the spinous process of which, long and pointed, well deserves
+the name of <i>the prominent</i> which is bestowed on it; but it
+should not be forgotten that the spinous process of the axis
+is equally developed.</p>
+
+<p>On the inferior surface of the body of each of the vertebr&aelig;
+is found a prominent crest, especially well marked at the
+posterior part; this crest is but slightly developed in the
+bear and in the cat tribe, and is not found in swine.</p>
+
+<p>The transverse processes of the cervical vertebr&aelig;, from
+their relation to the trachea, are known as the <i>tracheal
+processes</i>.</p>
+
+<p>The most marked characteristic of the dorsal vertebr&aelig; is
+furnished by the spinous processes. They are long and
+narrow. As a rule, the spinous processes of the foremost<span class="pagenum"><a name="Page_9" id="Page_9">[9]</a></span>
+dorsal vertebr&aelig; are the most developed and are directed
+obliquely upwards and backwards. As we approach the
+last vertebr&aelig; of this region, the processes become shorter
+and tend to become vertical, and the last ones are even, in
+some cases, directed upwards and forwards; this disposition
+is well marked in the dog and the cat. In the cetaceans, on
+the contrary, the length of the spinous processes increases
+from the first to the last.</p>
+
+<p>In the horse the spinous processes of the first dorsal
+vertebr&aelig; produce the prominence at the anterior limit of the
+trunk, where the mane ends, which is known as the <i>withers</i>.</p>
+
+<div class="figmed"><a name="Fig004" id="Fig004"></a>
+<img src="images/illo030.png" alt="Fig. 4" width="350" height="432" />
+<p class="caption just">Fig. 4.&mdash;Lumbar Vertebr&aelig; of a Quadruped (the Horse): Superior
+Surface.</p>
+
+<p class="subcaption just">1, Spinous process; 2, anterior articular process and transverse process
+of the first lumbar vertebra of the left side; 3, costiform process.</p></div>
+
+<p>The lumbar vertebr&aelig; are thicker than the preceding;
+they are known by their short and latterly-flattened spinous
+processes, and still more readily by their transverse processes,
+which, as they are evidently atrophied ribs, it is more
+accurate to denominate costiform processes (<a href="#Fig004">Fig. 4</a>). These
+are long, flattened from above downwards, and directed
+outwards and forwards.</p>
+
+<p>The true transverse processes are represented by tubercles<span class="pagenum"><a name="Page_10" id="Page_10">[10]</a></span>
+situated on the superior borders of the articular processes
+of each of the vertebr&aelig; of the lumbar region. Apropos of
+these different osseous processes, we are reminded that they
+are also present in the human skeleton.</p>
+
+<p>In the horse the costiform processes of the fifth and sixth
+lumbar vertebr&aelig; articulate, and are sometimes ankylosed,
+one with the other; the terminal ones articulate with the base
+of the sacrum. Sometimes the processes of the fourth and
+fifth are thus related; this is the case in the figure (<a href="#Fig004">4</a>) given;
+here the costiform processes of the fourth and fifth vertebr&aelig;
+articulate, and the two terminal ones have coalesced.</p>
+
+<p>In the ox, the same processes are more developed than in
+the horse; their summits elevating the skin, produce,
+especially in animals which have not much flesh, prominences
+which limit the flanks in the superior aspect. The costiform
+processes of the last lumbar vertebr&aelig; are separate from each
+other; those of the latter are not in contact with the sacrum.</p>
+
+<p><b>The Sacrum.</b><a name="FNanchor_3_3" id="FNanchor_3_3"></a><a href="#Footnote_3_3"
+class="fnanchor">[3]</a>&mdash;This bone, single and median, is
+formed by the mutual coalescence of several vertebr&aelig;, which
+vary in number according to the species observed.</p>
+
+<div class="footnote"><p><a name="Footnote_3_3" id="Footnote_3_3"></a><a href="#FNanchor_3_3"><span class="label">[3]</span></a> In
+human anatomy, the sacrum and the coccyx are studied as part
+of the pelvis; we, therefore, in the study of the artistic anatomy of
+man, study these bones with the bones of the lower limbs. Here we do
+not follow this plan. In animals the sacrum and the coccyx, as a matter
+of fact, clearly continue the superior border of the skeleton of the trunk;
+hence we study them with the vertebral column.</p></div>
+
+<p><i>Vertebr&aelig; Constituting the Sacrum.</i>&mdash;Bears, 5; dogs, 3;
+cats, 3; rabbits, 4; swine, 4; horses, 5; camels, 4;
+oxen, 5; sheep, 4.</p>
+
+<p>The sacrum is situated between the two iliac bones; with
+which it articulates, and contributes to the formation of the
+pelvis. It is obliquely placed, from before backwards, and
+from below upwards; immediately behind the lumbar
+section of the vertebral column; and is continued by the
+coccygeal vertebr&aelig;, which form the skeleton of the tail.</p>
+
+<p>It is triangular in outline, and is generally more narrow in
+proportion than in the human being. All things considered,
+it is more large and massive, and of greater density, in species
+which sometimes assume the upright posture, rather than in<span class="pagenum"><a name="Page_11" id="Page_11">[11]</a></span>
+those which cannot assume that attitude; for example, the
+sacrum of the ape, of the bear, of the dog, and of the opossum
+are proportionately larger than those of the horse.<a name="FNanchor_4_4" id="FNanchor_4_4"></a><a
+href="#Footnote_4_4" class="fnanchor">[4]</a></p>
+
+<div class="footnote"><p><a name="Footnote_4_4" id="Footnote_4_4"></a><a href="#FNanchor_4_4"><span class="label">[4]</span></a> This
+is particularly striking only in those portions of the sacrum that
+are not in relation with the other bones of the pelvis. We think that
+the general form of this bone depends on the mode of its connexions with
+the iliac bones and the extent of the articular surfaces by which it is in
+contact with the latter.</p></div>
+
+<p>Its superior surface presents a crest, formed by the fusion
+of the spinous processes of the vertebr&aelig; which form it. In
+certain species these processes are attached only by their
+bases, and are separated from each other superiorly. In
+the pig they are wholly wanting.</p>
+
+<p><b>The Coccygeal Vertebr&aelig;.</b>&mdash;These vertebr&aelig;, few in
+number (and sometimes ankylosed) in the human being,
+form in the latter a small series, the coccyx; which is inclined
+forwards, that is to say, towards the interior of the
+pelvis. In quadrupeds, on the contrary, their number is
+large; they are not ankylosed, and they form the skeleton
+of the caudal appendix.</p>
+
+<p>The first coccygeal vertebr&aelig;&mdash;that is, those which are next
+the sacrum&mdash;present characters which are common to those
+of other regions: they have a body, a foramen, and processes.
+As we trace them backwards, these characters become
+gradually effaced; and they become little more than
+small osseous cylinders simply expanded at their extremities.</p>
+
+<h5>Direction and Form of the Spinal Column</h5>
+
+<p>The curves of the vertebral column are, in quadrupeds,
+slightly different from those which characterize the human
+spine. First, instead of their being, as in the latter, curves
+in the antero-posterior aspect, because of the general attitude
+of the body, they are turned in the supero-inferior direction.</p>
+
+<p>The cervical region is not a single curve, as in the human
+being. It presents two: one superior, with its convexity
+looking upwards; the other inferior, the convexity of which
+is turned downwards. This arrangement reminds one of
+that of a console.</p>
+
+<p><span class="pagenum"><a name="Page_12" id="Page_12">[12]</a></span>The dorsal and lumbar regions are placed in a single curved
+line, more or less concave downwards; so that in the lumbar
+region there is no curve analogous to that which exists in
+man; a form which, in the latter, is due to the biped attitude&mdash;that
+is to say, the vertical position of the trunk.
+Briefly, there is in quadrupeds one dorso-lumbar curve; and
+not both a dorsal and a lumbar, with convexities in opposite
+directions.</p>
+
+<p>At the extremity of the dorso-lumbar region is the
+sacrum and the caudal appendix, which describe a curve
+of which the concavity is directed downwards and forwards.</p>
+
+<p>It is necessary to point out that it is not the curves of the
+three anterior portions of the spinal column which determine
+the form of the superior border of the neck and
+shoulders, and of the same part of the trunk. For the first
+portion, there is a ligament which surmounts the cervical
+region, and substitutes its modelling influence for that of the
+vertebr&aelig;. It is the <i>superior cervical ligament</i>, which arises
+from the spinous process of the first cervical vertebr&aelig;, and is
+inserted into the external occipital protuberance on the
+upper part of the posterior surface of the skull. The summits
+of the spinous processes of the vertebr&aelig; alone give form to
+the superior median border of the trunk. In this connection
+we here repeat that it is not the general curvature of the
+vertebral column which produces the withers, but the great
+length of the spinous process of the first vertebr&aelig; of the
+dorsal region.</p>
+
+<h5>The Thorax</h5>
+
+<p>The dorsal vertebr&aelig; form the posterior limit in man, and
+superior in quadrupeds, of the region of the trunk known
+as the <i>thorax</i>. A single bone, the sternum, is situated at
+the aspect opposite; the ribs bound the thorax on its sides.</p>
+
+<p>In its general outlines the thorax in quadrupeds resembles
+that of man&mdash;that is to say, that, as in the latter, the anterior
+portion&mdash;superior in the human being&mdash;is narrower than the
+part opposite. But the progressive widening takes place in
+a more regular and continuous fashion, so that it presents<span class="pagenum"><a name="Page_13" id="Page_13">[13]</a></span>
+a more definitely conical outline. This purely conical form
+is nevertheless found in the human species, but only during
+infancy; the inferior portion of the thoracic cage being then
+widely expanded, because of the development of the abdominal
+viscera, which at that period are relatively large.</p>
+
+<div class="figmed"><a name="Fig005" id="Fig005"></a>
+<img src="images/illo034.png" alt="Fig. 5" width="350" height="223" />
+<p class="caption just">Fig. 5.&mdash;A Transverse Section of the Thorax of a Man placed
+Vertically&mdash;that is to say, in the Direction which it would
+assume in a Man placed in the Attitude of a Quadruped (a
+Diagrammatic Figure).</p>
+
+<p class="subcaption just">1, Dorsal vertebra; 2, sternal region; 3, costal region of one side;
+3&#8242;, costal region of the other side.</p></div>
+
+<p>But the proportionate measurements of the thorax are
+different. Indeed, we may recall that in man the thorax is
+flattened from before backwards, so that the distance
+between the sternum and the vertebral column is shorter
+than the distance from the rib of one side to the corresponding
+one of the opposite side (<a href="#Fig005">Fig. 5</a>). In animals, on the
+contrary, it is flattened laterally. Its vertical diameter&mdash;measured
+from the sternum to the vertebral column&mdash;is
+greater than the transverse measurement (<a href="#Fig006">Fig. 6</a>).</p>
+
+<div class="figmed"><a name="Fig006" id="Fig006"></a>
+<img src="images/illo035.png" alt="Fig. 6" width="200" height="390" />
+<p class="caption just">Fig. 6.&mdash;A Vertical Section of the Thorax of a Quadruped
+(Diagrammatic).</p>
+
+<p class="subcaption just">1, Fifth dorsal vertebra; 2, sternal region; 3, costal region of one side;
+3&#8242;, costal region of the opposite side.</p></div>
+
+<p>From this results a peculiar arrangement of the muscles
+that we are able to bring directly into prominence, which
+presents points of interest from the point of view of the contraction
+of the subcutaneous layer. Indeed, in man the
+region occupied by the pectorals is very broad; it is a wide
+surface turned directly forward. In quadrupeds, this region
+of the pectorals is narrowed. It is not spread out, as in the
+preceding instances; and the appearance it presents is
+explained by the fact that the thorax is compressed laterally.
+If we examine the thorax on one of its lateral surfaces, the
+muscles, on the contrary, are more extended. We see the
+contour of the vertebral column, and the median part of the
+abdomen; and, especially in the horse, between the great<span class="pagenum"><a name="Page_14" id="Page_14">[14]</a></span>
+dorsal and the great oblique of the abdomen, we find a large
+space, in which the ribs, with the intercostals which join them,
+are uncovered; the muscles in question separate the one
+from the other, under the influence, it would seem, of the
+great dimensions of the lateral wall of the thorax.</p>
+
+<p><b>The Sternum.</b>&mdash;The sternum is, in quadrupeds, directed
+obliquely downwards and backwards; its form varies in
+different species. In the carnivora, it consists of eight bones,
+irregularly cylindrical in form, being slightly flattened from
+within outwards, and thickened at their extremities. They
+remain separate, and this contributes elasticity and flexibility
+to the thorax. The first nine costal cartilages articulate
+directly with the sternum. The first of these cartilages
+articulates with a nodule situated a little above the middle
+of the first bone of the sternum.</p>
+
+<p>In the horse the sternum is flattened laterally in its
+anterior portion, and from above downwards in its posterior<span class="pagenum"><a name="Page_15" id="Page_15">[15]</a></span>
+half. The six bones which form the sternum are connected
+by cartilage. The keel-shaped piece, situated in front of the
+sternum, is also cartilaginous. This process, but slightly
+marked posteriorly, becomes more and more prominent in
+front, and terminates at its anterior extremity by a prolongation,
+slightly curved backwards, which projects for some
+centimetres beyond the cavity in which the first costal
+cartilage is received. This process is known as the <i>tracheal
+process</i>, or <i>rostral cartilage</i>. The posterior extremity of the
+sternum, flattened from above downwards, ends in a cartilaginous
+plate; concave superiorly, and convex inferiorly:
+this is the abdominal prolongation, or <i>xiphoid appendix</i>.</p>
+
+<p>In the ox, the sternum is formed of two distinct bones,
+which are united by an articulation. One, the anterior, is
+short, and forms the first portion of the sternum; it is
+slightly flattened from side to side, and vertical in direction.
+The other, the posterior, is longer, and is formed by the
+fusion of several small bones; it is placed horizontally, and
+is flattened from above downwards. At the level of articulation
+of these two portions, and because of their different
+directions, the bone is bent. This bend occurs at the point
+of articulation of the second costal cartilage. On the
+superior border of the anterior segment the cartilage of
+the first rib is articulated. The xiphoid appendix, which
+is cartilaginous, is attached to the extremity of a long
+process of the last bone of the sternum.</p>
+
+<p>The shape of the anterior extremity of the sternum is
+influenced by the presence or absence of clavicles. We have
+seen that in some quadrupeds the clavicles are wanting. In
+the first case, this extremity is large, and approaches in shape
+to the corresponding part of the human sternum, which is so
+clearly designed to give a point of support to the anterior
+bone of the shoulder. In the second, on the contrary, this
+extremity is narrow.</p>
+
+<p>The sternum in birds is very different from that in mammalia,
+which we have been studying. It varies greatly in
+extent and shape, under the influence of certain conditions.
+To understand the cause of these variations it is necessary
+to remember that in man (as, indeed, in other animals; but<span class="pagenum"><a name="Page_16" id="Page_16">[16]</a></span>
+the example of man, for that which follows, will be more
+striking, on account of the mobility of his upper limbs) the
+sternum gives origin to the pectoral muscles, and that these
+muscles are inserted into other parts of the thoracic limbs,
+designed by their contraction to draw the arms downwards,
+forwards, and inwards&mdash;that is, when these are in a state of
+abduction and in a horizontal direction, they draw them
+towards the anterior surface of the thorax and downwards.
+Now, this movement is similar to that made by birds
+during flight. It is necessary to add that, in the latter
+case, the more the displacement of the upper limbs has
+of force and extent, the more the pectoral muscles are
+developed.</p>
+
+<p>For these reasons, birds, in which, during flight, the movements
+of the thoracic limbs&mdash;the wings&mdash;are necessarily
+energetic, present a great development of the pectoral
+muscles; having consequently, because an extent of surface
+for the origin of the muscles commensurate with their development
+is necessary, a very large and peculiarly shaped
+sternum (<a href="#Fig018">Figs. 18</a>, 6; and <a href="#Fig021">21</a>, 6). Indeed, not only is the
+sternum large, but, further, in order to form a deeper surface,
+proportionately adapted to the muscles which arise from and
+cover it, its anterior surface presents, in the median line, a
+prominent crest known as the <i>keel</i>. This prominence forms
+two lateral foss&aelig;. We cite as examples, the sternum of the
+eagle, the vulture, the falcon, and the hawk.</p>
+
+<div class="figmed"><a name="Fig007" id="Fig007"></a>
+<img src="images/illo038.png" alt="Fig. 7" width="350" height="477" />
+<p class="caption just">Fig. 7.&mdash;Sternum of a Bird (the Cock): Left Side, External Surface.</p>
+
+<p class="subcaption just">1, Keel; 2, internal slot; 3, external slot; 4, internal process; 5, external
+process; 6, inferior ribs; 7, costal process; 8, surface for articulation
+with the coracoid bone.</p></div>
+
+<p>All birds are not, however, equally adapted to flight, for
+in the domestic cock, which flies but a short distance, and
+badly, the sternum is less developed (<a href="#Fig007">Fig. 7</a>); it is also
+diminished by slots, which diminish its surface. These slots,
+two on each side, are called from their position the internal
+and external slots. They are bounded by narrow, elongated,
+bony processes, an internal and an external; the expanded
+lower extremity of the latter overlaps the last inferior ribs
+(see <a href="#Page_19">p. 19</a>). The part of the external border which surmounts
+this external process is hollowed out into grooves, which
+receive the inferior ribs, and terminates superiorly in an
+osseous projection known as <i>the costal prominence</i>.</p>
+
+<p>In the ostrich, the cassowary, and the apteryx, which run,<span class="pagenum"><a name="Page_17" id="Page_17">[17]</a></span>
+but do not fly, the sternum has the form of a plate of bone
+slightly convex, but without a keel.</p>
+
+<p>The shape of the sternum, correlated to the faculty of
+flight (or of swimming; apropos of which we may cite the
+penguin, of which the rudimentary wings resemble fins,
+and perform their functions only), or the absence of this
+faculty, has furnished the division of birds into two groups.
+In one are included, under the name <i>Carinates</i> (<i>carina</i>, keel),
+those in which the sternum is provided with a keel; in the
+other division are those in which the sternum is not furnished
+with one. These latter, on account of their unique mode of
+progression, are more nearly allied to the mammals.</p>
+
+<p>The keel is developed in flying mammals (bats).</p>
+
+<p><b>Ribs and Costal Cartilages.</b>&mdash;There are on each side
+of the thorax as many ribs as there are dorsal vertebr&aelig;.
+In animals, as in man, the ribs which articulate with the
+sternum by their cartilages are called <i>true</i>, or <i>sternal</i> ribs;
+those whose cartilages do not articulate with the sternum<span class="pagenum"><a name="Page_18" id="Page_18">[18]</a></span>
+are called <i>false</i>, or <i>asternal</i>. The longer ribs are those
+situated in the middle region of the thorax.</p>
+
+<p>The ribs are directed obliquely downwards and backwards,
+and this obliquity is more marked in the posterior ones than
+in the anterior. They are, however, less oblique than in
+the human being; what proves this is that the first rib in man
+is oblique, while in quadrupeds it is vertical.</p>
+
+<p>The curvature of the ribs is less pronounced in quadrupeds
+than in the human being, but this is not equal in all animals.
+The ribs of the bear are more curved than those of the dog;
+the latter has ribs more curved than those of the horse.</p>
+
+<p>Each rib, at its vertebral extremity, presents, from within
+outwards, a wedge-shaped head for articulation with two
+dorsal vertebr&aelig;, a neck, and a tuberosity. External to the
+tubercle are found some rough impressions, for muscular
+attachments, which correspond to the angle of the human
+rib.</p>
+
+<p>In the following table, we give the number and classification
+of the ribs of some animals:</p>
+
+<h6><span class="smcap">Number of the Ribs on Each Side of the Thorax.</span></h6>
+
+<table class="fsize80" summary="Table page 18">
+
+<tr>
+<td colspan="4">&nbsp;</td>
+<td class="center">Sternal.</td>
+<td>&nbsp;</td>
+<td class="center">Asternal.</td>
+</tr>
+
+<tr>
+<td class="left padr5">Bear</td>
+<td class="center padl1 padr1">14</td>
+<td class="center padl1 padr1">divided</td>
+<td class="center padl1 padr1">into</td>
+<td class="center padl1 padr1">9</td>
+<td class="center padl1 padr1">and</td>
+<td class="center padl1 padr1">5</td>
+</tr>
+
+<tr>
+<td class="left padr5">Dog</td>
+<td class="center padl1 padr1">13</td>
+<td class="center padl1 padr1">&#8222;</td>
+<td class="center padl1 padr1">&#8222;</td>
+<td class="center padl1 padr1">9</td>
+<td class="center padl1 padr1">&#8222;</td>
+<td class="center padl1 padr1">4</td>
+</tr>
+
+<tr>
+<td class="left padr5">Cat</td>
+<td class="center padl1 padr1">13</td>
+<td class="center padl1 padr1">&#8222;</td>
+<td class="center padl1 padr1">&#8222;</td>
+<td class="center padl1 padr1">9</td>
+<td class="center padl1 padr1">&#8222;</td>
+<td class="center padl1 padr1">4</td>
+</tr>
+
+<tr>
+<td class="left padr5">Rabbit</td>
+<td class="center padl1 padr1">12</td>
+<td class="center padl1 padr1">&#8222;</td>
+<td class="center padl1 padr1">&#8222;</td>
+<td class="center padl1 padr1">7</td>
+<td class="center padl1 padr1">&#8222;</td>
+<td class="center padl1 padr1">5</td>
+</tr>
+
+<tr>
+<td class="left padr5">Pig</td>
+<td class="center padl1 padr1">14</td>
+<td class="center padl1 padr1">&#8222;</td>
+<td class="center padl1 padr1">&#8222;</td>
+<td class="center padl1 padr1">7</td>
+<td class="center padl1 padr1">&#8222;</td>
+<td class="center padl1 padr1">7</td>
+</tr>
+
+<tr>
+<td class="left padr5">Horse</td>
+<td class="center padl1 padr1">18</td>
+<td class="center padl1 padr1">&#8222;</td>
+<td class="center padl1 padr1">&#8222;</td>
+<td class="center padl1 padr1">8</td>
+<td class="center padl1 padr1">&#8222;</td>
+<td class="center padl1 padr1">10</td>
+</tr>
+
+<tr>
+<td class="left padr5">Camel</td>
+<td class="center padl1 padr1">12</td>
+<td class="center padl1 padr1">&#8222;</td>
+<td class="center padl1 padr1">&#8222;</td>
+<td class="center padl1 padr1">8</td>
+<td class="center padl1 padr1">&#8222;</td>
+<td class="center padl1 padr1">4</td>
+</tr>
+
+<tr>
+<td class="left padr5">Ox</td>
+<td class="center padl1 padr1">13</td>
+<td class="center padl1 padr1">&#8222;</td>
+<td class="center padl1 padr1">&#8222;</td>
+<td class="center padl1 padr1">8</td>
+<td class="center padl1 padr1">&#8222;</td>
+<td class="center padl1 padr1">5</td>
+</tr>
+
+<tr>
+<td class="left padr5">Sheep</td>
+<td class="center padl1 padr1">13</td>
+<td class="center padl1 padr1">&#8222;</td>
+<td class="center padl1 padr1">&#8222;</td>
+<td class="center padl1 padr1">8</td>
+<td class="center padl1 padr1">&#8222;</td>
+<td class="center padl1 padr1">5</td>
+</tr>
+
+</table>
+
+<p>The costal cartilages, by which the first ribs are united to
+the sternum (sternal ribs), whilst the latter are united one
+to the other without being directly connected with the
+sternum (asternal ribs), are, as a rule, in quadrupeds, directed
+obliquely downwards, forwards, and inwards; each forms,
+with the rib to which it belongs, an obtuse angle more or less
+open anteriorly. Their length is proportionate to that of
+the ribs. The cartilages, which are continued from the
+asternal ribs, unite and form the borders, directed obliquely
+downwards and forwards, of the fossa which is found at the<span class="pagenum"><a name="Page_19" id="Page_19">[19]</a></span>
+inferior and posterior part of the thorax, and which forms
+the lateral limits of the epigastric region. In the dog and cat
+the ribs are thick and almost cylindrical; the costal cartilages
+are thicker at the margin of the sternum than at their
+costal extremity. In the ox, the ribs are flattened laterally
+and are very broad, the more so as we examine a portion
+further from the vertebral column. From the second to the
+twelfth they are quadrangular in the superior fourth, and
+thicker than in the rest of their extent. The first costal
+cartilage is vertical; the following ones are progressively
+more oblique in a direction downwards and forwards. The
+four or five cartilages which succeed the first unite with slight
+obliquity to the sternum; their union with that bone gives
+the impression of a very strong, well-knit apparatus. The
+costal cartilages which unite with the sternum are flattened
+laterally in the portions next the ribs, and flattened from
+front to back in the rest of their extent.</p>
+
+<p>In the horse the ribs increase in length from the first to the
+ninth; they are flattened from without inwards, and increase
+in width from the first to the sixth or seventh, and the following
+ones become narrower. The costal cartilages, from
+the second to the eighth, are, as in the ox, at first flattened
+laterally, near the ribs; while near the sternum they are
+flattened from front to back.</p>
+
+<p>In birds, the ribs are each furnished with a flat process
+(<a href="#Fig018">Fig. 18</a>, 10), which springs from the posterior border, is
+directed backwards, and overlaps the external surface of
+the succeeding rib. These processes are not found, as a rule,
+on the first or last ribs.</p>
+
+<p>As for the costal cartilages, they are, as a rule, ossified,
+and receive the name of inferior ribs (<a href="#Fig018">Fig. 18</a>, 11), united to
+the preceding (superior ribs; <a href="#Fig018">Fig. 18</a>, 9) by articulation;
+by the other extremity they are joined to the sternum; the
+first superior ribs generally want them. Sometimes the last
+inferior rib becomes connected with the one that precedes it,
+not articulating with the sternum; and thus recalls the
+relations of the asternal ribs which we have noticed in our
+study of the mammals.</p>
+
+<p>In the bat, as in birds, the costal cartilages are ossified.</p>
+
+<p class="pagenum"><a name="Page_20" id="Page_20">[20]</a></p>
+
+<h4>THE ANTERIOR LIMBS<a name="FNanchor_5_5" id="FNanchor_5_5"></a><a href="#Footnote_5_5"
+class="fnanchor" style="font-weight: normal;">[5]</a></h4>
+
+<div class="footnote"><p><a name="Footnote_5_5" id="Footnote_5_5"></a><a href="#FNanchor_5_5"><span class="label">[5]</span></a> Consult
+<a href="#Fig021">Figs. 21</a>, <a href="#Fig033">33</a>, <a href="#Fig034">34</a>, <a href="#Fig038">38</a>,
+<a href="#Fig039">39</a>, <a href="#Fig046">46</a>.</p></div>
+
+<p>The anterior limbs, homologous to the upper limbs in
+man, are formed, as in the latter, of four segments: the
+shoulder, the arm, the forearm, and the hand. These limbs,
+considered in the vertebral series, present themselves under
+very different aspects, which are determined by the functions
+they are called upon to perform.</p>
+
+<div class="figlarge"><a name="Fig008" id="Fig008"></a>
+<img src="images/illo041.png" alt="Fig. 8" width="600" height="335" />
+<p class="caption just">Fig. 8.&mdash;Anterior Limb of the Bat: Left Side, Anterior Surface.</p>
+
+<p class="subcaption just">1, Clavicle; 2, scapula; 3, humerus; 4, radius; 5, cubitus; 6, carpus;
+7, thumb; 8, metacarpus; 9, phalanges.</p></div>
+
+<p>They constitute the forepaw in terrestrial mammals; in
+aerial vertebrates they form wings; in aqueous mammals
+they act as paddles. In whatever series we study them,
+we can readily find the relationship of the different parts;
+it is very easy to recognise the same bones in the upper limbs
+of the human being, the wings of the bat (<a href="#Fig008">Fig. 8</a>) and of
+birds (<a href="#Fig021">Fig. 21</a>), and in the anterior paddles of the seal (<a href="#Fig009">Fig. 9</a>)
+and of the dolphin.</p>
+
+<div class="figlarge"><a name="Fig009" id="Fig009"></a>
+<img src="images/illo042.png" alt="Fig. 9" width="600" height="395" />
+<p class="caption just">Fig. 9.&mdash;Anterior Limb of the Seal: Left Side, External Surface.</p>
+
+<p class="subcaption just">1, Scapula; 2, humerus; 3, radius; 4, ulna; 5, carpus;
+6, metacarpus; 7, phalanges of the fingers.</p></div>
+
+<p>In quadrupeds, the shoulder and arm are hidden, the
+latter more or less completely, in the muscular mass which
+binds it to the lateral wall of the trunk; so that the anterior
+limbs only present; free from the trunk: the elbow, forearm,
+and hand.</p>
+
+<h5>The Shoulder</h5>
+
+<p>In some vertebrates, the shoulder is formed of two bones&mdash;the
+scapula and clavicle; in others of only one bone&mdash;the
+scapula; the clavicle in this case does not exist.</p>
+
+<p><span class="pagenum"><a name="Page_21" id="Page_21">[21]</a></span><b>The Scapula or Omoplate.</b>&mdash;The scapula is situated
+on the lateral surface of the thorax, and is directed obliquely,
+from above downwards and from behind forwards.</p>
+
+<p>We must first recall, so as to be able to make a comparison,
+that in man this bone is placed at the posterior surface of the
+thoracic cage; so that if we look at the human thorax
+on one of its lateral aspects we see chiefly the external
+border of the scapula; it is the external surface (homologous
+to the posterior surface of the human scapula) which
+we see in its full extent when we look on the same surface
+of the thorax in quadrupeds.</p>
+
+<div class="figmed"><a name="Fig010" id="Fig010"></a>
+<img src="images/illo043a.png" alt="Fig. 10" width="250" height="196" />
+<p class="caption just">Fig. 10.&mdash;Situation and Direction
+of the Scapula in the
+Human Being, the Trunk being
+Horizontal, as in Quadrupeds.
+Vertical and Transverse Section
+of the Thorax (Diagrammatic
+Figure).</p>
+
+<p class="subcaption just">1, Contour of the thorax; 2, 2, the
+scapula.</p></div>
+
+<div class="figmed"><a name="Fig011" id="Fig011"></a>
+<img src="images/illo043b.png" alt="Fig. 11" width="200" height="370" />
+<p class="caption just">Fig. 11.&mdash;Position and Direction
+of the Scapula in Quadrupeds.
+Vertical and Transverse Section
+of the Thorax (Diagrammatic
+Figure).</p>
+
+<p class="subcaption just">1, Contour of the thorax; 2, 2, the
+scapula.</p></div>
+
+<p>To sum up, if we fancy the human being in the position
+of the quadruped, the scapula will have its surfaces almost
+parallel to the ground (<a href="#Fig010">Fig. 10</a>); while in quadrupeds, the
+surfaces are situated in a plane which is almost perpendicular
+to the ground (<a href="#Fig011">Fig. 11</a>). This position of the scapula in an
+almost vertical plane is designed to give the necessary point
+of support to the osseous columns that form the skeleton
+of the other portions of the anterior limbs.</p>
+
+<div class="figmed"><a name="Fig012" id="Fig012"></a>
+<img src="images/illo044a.png" alt="Fig. 12" width="250" height="259" />
+<p class="caption just">Fig. 12.&mdash;Left Scapula of
+the Human Being, Posterior
+Surface, placed
+in the Position which
+it would Occupy in the
+Skeleton of a Quadruped.</p>
+<p class="subcaption just">1, Cervical border; 2, spinal border&mdash;the
+scapula here represented, being from
+a hoofed animal, has a cartilage of extension
+attached to its spinal border; 3,
+axillary border; 4, supraspinous fossa;
+5, subspinous fossa; 6, spine of the
+scapula; 7, glenoid cavity; 8, coracoid
+process. The scapula of the horse has no
+acromion process, but it is easy, if we
+compare the human scapula, to judge of
+the position which this process would
+occupy if it were present.</p></div>
+
+<p>Because of this position of the scapula (<a href="#Fig012">Figs. 12</a> and <a href="#Fig013">13</a>),
+the spinal border is superior, the cervical, anterior, and the
+axillary, posterior. In direct contrast to what obtains in the
+human scapula, the spinal border is the shortest of the<span class="pagenum"><a name="Page_22" id="Page_22">[22]</a></span>
+three; except in the bat, and the majority of the
+cetaceans.</p>
+
+<div class="figmed"><a name="Fig013" id="Fig013"></a>
+<img src="images/illo044b.png" alt="Fig. 13" width="300" height="374" />
+<p class="caption top">Fig. 13.&mdash;Left Scapula of a Horse:
+External Surface.</p>
+
+<p class="subcaption just">1, Cervical border; 2,
+spinal border; 3, axillary
+border; 4, supraspinous fossa;
+5, subspinous fossa; 6,
+scapular spine; 7, glenoid
+cavity; 8, coracoid process;
+9, acromion process.</p></div>
+
+<p>In certain animals (in the ungulates [<i>hoofed</i><a name="FNanchor_6_6"
+id="FNanchor_6_6"></a><a href="#Footnote_6_6" class="fnanchor">[6]</a>]&mdash;pigs, oxen,
+sheep, horses) the superior, or spinal, border of the scapula is
+surmounted by a cartilage called <i>the cartilage of prolongation</i>.</p>
+
+<div class="footnote"><p><a name="Footnote_6_6" id="Footnote_6_6"></a><a href="#FNanchor_6_6"><span class="label">[6]</span></a> For
+the definition of the word <i>hoofed</i>, see <a href="#Page_37">p. 37</a>.</p></div>
+
+<div class="figmed"><a name="Fig014" id="Fig014"></a>
+<img src="images/illo045a.png" alt="Fig. 14" width="200" height="311" />
+<p class="caption just">Fig. 14.&mdash;Vertical and Transverse
+Section, at the Site of the
+Shoulders, of the Thorax of the
+Horse (Diagrammatic Figure).</p>
+
+<p class="subcaption just">1, Outline of the thorax at the level
+of the third dorsal vertebra; 2, 2,
+scapula; 3, spinal border of the
+scapula; 4, cartilage of prolongation;
+5, contour of the skin.</p></div>
+
+<p>This is the cause why the border to which it is fixed is so
+slightly noticeable under the skin in these animals; indeed,
+in the upper part, the bone and cartilage are not distinguishable
+in the contour of the corresponding region of the back;
+being applied to the lateral surfaces of the spinous processes,
+the prominence formed by the extremities of which is directly
+continuous with the plane of the scapula (<a href="#Fig016">Fig. 16</a>).</p>
+
+<div class="figmed"><a name="Fig015" id="Fig015"></a>
+<img src="images/illo045b.png" alt="Fig. 15" width="200" height="294" />
+<p class="caption just">Fig. 15.&mdash;Vertical and Transverse
+Section, at the Plane
+of the Shoulders, of the
+Thorax of a Dog (Diagrammatic
+Figure).</p>
+
+<p class="subcaption just">1, Outline of the thorax at the
+level of the third dorsal vertebra;
+2, 2, scapula; 3, spinal border of
+the scapula; 4, contour of the skin.</p></div>
+
+<p><span class="pagenum"><a name="Page_23" id="Page_23">[23]</a></span>In quadrupeds whose scapula, on the contrary, is wanting
+in the cartilage of prolongation (in the <i>clawed</i>,<a name="FNanchor_7_7"
+id="FNanchor_7_7"></a><a href="#Footnote_7_7" class="fnanchor">[7]</a> such as the
+cat and dog), the superior border of the scapula is visible,
+especially when the animal is resting on its fore-limbs, particularly
+when it crouches; at such a time the skin is markedly
+raised by that border; and the spinous processes of
+the vertebr&aelig;, beyond which it projects, occupy the bottom
+of a fossa (<a href="#Fig015">Fig. 15</a>). The internal surface of the scapula
+is turned towards the ribs; it is known, as in man (in whom
+this surface is anterior), as the subscapular fossa.</p>
+
+<div class="footnote"><p><a name="Footnote_7_7" id="Footnote_7_7"></a><a href="#FNanchor_7_7"><span class="label">[7]</span></a> For
+the definition of this word, see <a href="#Page_37">p. 37</a>.</p></div>
+
+<div class="figmed"><a name="Fig016" id="Fig016"></a>
+<img src="images/illo047a.png" alt="Fig. 16" width="200" height="54" />
+<p class="caption center">Fig. 16.&mdash;Left Clavicle of the Cat:
+Superior Surface (Natural Size).</p>
+
+<p class="subcaption center">1, Internal extremity; 2, external extremity.</p></div>
+
+<div class="figmed"><a name="Fig017" id="Fig017"></a>
+<img src="images/illo047b.png" alt="Fig. 17" width="62" height="83" />
+<p class="caption center">Fig. 17.&mdash;Clavicle of the
+Dog (Natural Size).</p></div>
+
+<p>Its external surface is divided into two parts by the spine
+of the scapula; which, in some animals, terminates inferiorly
+in a flat and clearly distinct process, the homologue of the<span class="pagenum"><a name="Page_24" id="Page_24">[24]</a></span>
+acromion process of the human scapula. The two regions
+separated by the spine are known as the supraspinous fossa
+and the infraspinous fossa. The supraspinous fossa is anterior
+to the spine, and the infraspinous is posterior to it. The
+surfaces of the scapula are, in quadrupeds, flatter than
+in the human being, and in particular the subscapular fossa,
+which is also less concave. Some authors attribute this to
+the lesser curvature of the ribs in quadrupeds. A few words
+will suffice to prove that there must be another reason.
+The scapula is not in immediate contact with the ribs; the
+subscapular fossa is not moulded on them. Besides, the
+form of the scapula is, as in other parts of the skeleton,
+dependent on the disposition of muscles, and the development
+of these latter is correlated to the extent and energy
+of the movements which the individual is able or required<span class="pagenum"><a name="Page_25" id="Page_25">[25]</a></span>
+to execute. But the movements which those muscles
+produce (more especially the rotation of the humerus) are,
+in quadrupeds, less extensive than in the human being;
+and, consequently, the muscles which produce them are,
+proportionally, less strongly developed. The inferior angle
+(superior and external in man), situated at the junction of
+the cervical and axillary borders, presents the glenoid
+cavity, which, looking downwards, receives the articular
+surface of the superior extremity of the bone of the arm&mdash;that
+is to say, the head of the humerus. Above this
+cavity, on the lower part of the cervical border, is situated
+a tubercle which reminds us of the coracoid process of
+the human scapula. The region occupied by the glenoid
+cavity is separated from the body of the bone by a constriction&mdash;the
+neck of the scapula.</p>
+
+<div class="figmed"><a name="Fig018" id="Fig018"></a>
+<img src="images/illo048.png" alt="Fig. 18" width="300" height="352" />
+<p class="caption just">Fig. 18.&mdash;Skeleton of the Shoulder of a Bird (Vulture): Antero-External
+View of the Left Side.</p>
+
+<p class="subcaption just">1, Left clavicle; 2, inferior portion of the right clavicle, forming by its
+ankylosis with that of the other side the fourchette; 3, coracoid bone;
+4, scapula; 5, articular surface for humerus; 6, superior half of the
+sternum; 7, keel of sternum; 8, spinous process of the dorsal vertebr&aelig;;
+9, superior ribs; 10, process of one of these ribs; 11, inferior ribs.</p></div>
+
+<p>In birds the scapula is elongated in a direction parallel to
+the vertebral column, and very narrow in the opposite
+(<a href="#Fig018">Fig. 18</a>): it is also flat, and has no spine. Its coracoid
+process is represented by a peculiar bone&mdash;the coracoidean
+or coracoid bone&mdash;which we shall describe later on when
+we come to the study of the clavicle and of the anterior
+region of the shoulder (see <a href="#Page_26">p. 26</a>).</p>
+
+<p><b>The Clavicle.</b>&mdash;The clavicle is found only in the human
+being, and in animals whose anterior limbs, possessing
+great freedom of movement in all directions, require
+that the scapula should possess a point of support which,
+while affording this, can be displaced with it, or draw it
+in certain directions. Now, this point of support is
+furnished by the clavicle.</p>
+
+<p>In animals possessed of hoofs (ungulates), such as the
+sheep, ox, and horse, the clavicle does not exist. Indeed,
+in them the freedom of movement of the anterior limbs is
+limited; they move by projection in the forward and
+backward directions only; they merely fulfil the functions
+of giving support to and carrying about the body. The
+clavicle is rudimentary in the cat and the dog; in the cat
+it is a small, elongated bone (<a href="#Fig016">Fig. 16</a>), 2 centimetres in
+length, thin and curved, connected with the sternum and
+the scapula by ligamentous bundles. In the dog it is<span class="pagenum"><a name="Page_26" id="Page_26">[26]</a></span>
+represented by a small osseous plate only (<a href="#Fig017">Fig. 17</a>),
+which is not connected with any of the neighbouring
+bones.</p>
+
+<p>It is on the deep surface of a muscle which passes from
+the head and neck to the humerus (mastoido-humeral, a
+muscle common to the arm, neck, and head) in which this
+rudimentary bone is found to be developed.</p>
+
+<p>The clavicle exists in perfect state in mammals which
+use their limbs for digging, grasping, or flying; the insectivora
+(hedgehog, mole) and some rodents (squirrel, woodchuck)
+are provided with it.</p>
+
+<p>The cheiroptera (bats) possess an extremely well-developed
+clavicle, on account of the varied movements which their
+thoracic limbs execute.</p>
+
+<p>This formation of the shoulder which favours flight in
+the bat is even more remarkable in birds. In these latter
+(<a href="#Fig018">Fig. 18</a>) the clavicles, fused together by their lower extremities,
+form one bone, having the shape of the letter V or U,
+which is known as the <i>fourchette</i>; this bone, acting as a
+true spring, keeps the shoulders apart, and prevents their
+approximation during the energetic movements which flight
+necessitates.</p>
+
+<p>In birds whose power of flight is strong, the two limbs
+of this bone are widely separated and thick, and the fourchette
+is U-shaped. Those whose flight is awkward and
+but slightly energetic have the limbs of the fourchette
+slender; they unite at a more acute angle, and the bone is
+V shaped.</p>
+
+<p>Furthermore, a bone named the <i>coracoid</i> joins the scapula
+to the sternum; this bone, often fused with the scapula,
+where it contributes to the formation of the glenoid cavity,
+represents in birds the coracoid process of the human<span class="pagenum"><a name="Page_27" id="Page_27">[27]</a></span>
+scapula. If we fancy this process directed inwards, and
+sufficiently lengthened to join the sternum, we shall have
+an idea of the disposition of the bone we are now discussing,
+and the reasons for which the name has been chosen by
+which it is designated. The coracoid bone, like the fourchette
+which it reinforces, offers to the wings a degree of support
+proportionate to the efforts developed by those limbs; for
+this reason it is thick and solid in birds of powerful flight.</p>
+
+<p>The superior extremity of each branch of the fourchette,
+at the level of its junction with the coracoid and the scapula,
+bounds, with these latter, a foramen which gives passage to<span class="pagenum"><a name="Page_28" id="Page_28">[28]</a></span>
+the tendon of the elevator muscle of the wing, or small
+pectoral. The importance of the fourchette being, as we
+have seen, in proportion to the movements of flying, it is
+easy to understand that the bone is not found in the ostrich.</p>
+
+<h5>The Arm</h5>
+
+<p>A single bone, the humerus, forms the skeleton of this
+portion of the thoracic limb.</p>
+
+<p><b>The Humerus.</b>&mdash;The bone of the arm is, in quadrupeds,
+inclined from above downwards and from before backwards.</p>
+
+<p>It is, with relation to other regions, short in proportion
+as the metacarpus is elongated, and as the number of digits
+is lessened. In the horse, for example, whose metacarpus
+is long, and in which but one digit is apparent, the humerus
+is very short. The slight development in length of the
+humerus explains its close application to the side of the
+animal as far as the elbow.</p>
+
+<p>In animals in which the humerus is longer, the bone is
+slightly free, as well as the elbow, at its inferior extremity.
+<a href="#LongerHumerus">Later on</a> we will return to the consideration of this
+peculiarity and of the proportions of the humerus, after
+we have studied the other parts of the fore-limbs.</p>
+
+<p>The humerus in quadrupeds is inflected like the letter S;
+in man this general form is less accentuated, the humerus
+being almost straight. On its body, which appears twisted
+on its own axis, we find the musculo-spiral groove,<a name="FNanchor_8_8"
+id="FNanchor_8_8"></a><a href="#Footnote_8_8" class="fnanchor">[8]</a> which
+crosses the external surface, and is very deep in some animals.
+Above this groove, and on the external surface, there exists
+a rough surface which is the impression of the deltoid. In<span class="pagenum"><a name="Page_29" id="Page_29">[29]</a></span>
+some species this rugosity is very prominent, and is called
+<i>the tuberosity of the deltoid</i>; it is prolonged downwards by
+a border which forms the anterior crest of the musculo-spiral
+groove and limits this latter in front. The external border
+of the bone, or posterior crest of the groove, limits it behind.</p>
+
+<div class="footnote"><p><a name="Footnote_8_8" id="Footnote_8_8"></a><a href="#FNanchor_8_8"><span class="label">[8]</span></a> It
+would be going outside our province to discuss whether the
+humerus is really twisted on its axis. This question, often discussed, has
+been solved in some recent works in the following manner: the humerus
+has undergone torsion at the level of its superior extremity, and not
+at the level of its body; this does not authorize us further to accord any
+definite sense to the denomination &#8216;groove of torsion&#8217; (musculo-spiral
+groove). That which we must especially remember in connection with
+this fact, is, as we shall afterwards see, the difference of direction which the
+articular head presents according as the torsion has been more or less
+considerable: because this is established, according to the same order, in
+man and in quadrupeds.</p></div>
+
+<p>The superior extremity is enlarged, and remarkable in
+three portions which it presents; these are: an articular
+surface and two tuberosities.</p>
+
+<p>The articular surface, or head of the humerus, smooth and
+round, is in contact with the glenoid cavity of the scapula.
+This head in the human skeleton is directed upwards and inwards;
+in quadrupeds its direction is upwards and backwards.
+The inferior extremity, having in both one and
+the other its long axis directed transversely, and the point
+of the elbow looking backwards in all, the result is that the
+head of the humerus is not situated vertically above the
+same regions; in the first, it is almost directly above the
+internal part of this extremity; in the latter, it is situated
+above its posterior surface, or the point of the elbow in
+the complete skeleton. This difference of direction is correlated
+with the position of the scapula, the glenoid cavity
+of which, as we have already seen, is in man turned outwards,
+whereas in quadrupeds it looks downwards. In
+the latter case the scapula consequently rests on the head
+of the humerus; and this position is most favourable for the
+performance of the functions which the anterior limbs have
+to fulfil in these latter.</p>
+
+<p>Of the tuberosities of the head of the humerus, one is
+situated on the external aspect&mdash;it is the great tuberosity, or
+<i>trochiter</i>; the other is placed internally&mdash;it is the small
+tuberosity, or <i>trochin</i>. The great tuberosity is divided into
+three parts&mdash;summit, convexity, and crest; these different
+parts give insertion to the muscles of the shoulder. We
+recollect that the facets (anterior, middle, and posterior) of
+the great tuberosity of the humerus in man give attachment
+to the muscles of the same region. The head of the humerus
+in the human body projects above the tuberosities. We
+shall see afterwards, when dealing with some special quadrupeds,
+that in some of these, on the other hand, the tuberosities<span class="pagenum"><a name="Page_30" id="Page_30">[30]</a></span>
+are on a higher level than the articular head of the
+bone. Between the two tuberosities is the bicipital groove.</p>
+
+<p>In man, the superior extremity of the humerus, although
+covered by the deltoid, reveals its presence by elevating
+the corresponding portion of the latter. In quadrupeds, the
+anterior part of this extremity, although similarly covered by
+muscular bundles, produces a prominence under the skin.
+This prominence is situated at the summit of the angle
+formed by the opposing directions of the scapula and the
+bone of the arm, and constitutes what is known by
+the name of the <i>point of the shoulder</i>, or of the <i>point of
+the arm</i>.</p>
+
+<p>The inferior extremity, transversely enlarged, presents an
+undulating articular surface, which reminds us of the trochlea
+and the condyle of the human humerus; on which, however,
+the condyle is more sharply defined from the trochlea.</p>
+
+<p>In the human skeleton, the internal lip of the trochlea
+descends lower than the external; and also lower than the
+condyle. In the bear, the cat, and the dog, it is the same.
+In the ox and the sheep, the condyle is lower than the
+trochlea, but only very little lower. In the horse the
+arrangement is still the same, but a little more accentuated.</p>
+
+<p>On the lateral parts of this extremity we find: internally,
+a prominence, the epitrochlea; and, externally, another,
+the epicondyle. It is from this latter that the crest arises,
+which, passing upwards, forms the posterior limit of the
+groove of torsion.</p>
+
+<p>The two prominences, which we have just described from
+a general point of view, present special arrangements which
+it is necessary to point out. When we examine the form
+of the outline of the inferior extremity of the humerus in
+man, the bear, the cat, the dog, the ox, and the horse, we
+find in following this order that the extremity tends to
+become narrow transversely, and that the epicondyle and
+the epitrochlea are less and less prominent on the external
+and internal aspects respectively. These two processes,
+indeed, project backwards; the epitrochlea always remaining
+more developed than the epicondyle. Because of this
+projection backwards, the cavity situated on the posterior<span class="pagenum"><a name="Page_31" id="Page_31">[31]</a></span>
+surface of the inferior extremity, the olecranon fossa, is
+very deep, more so than in the humerus of man. Its borders
+being thus formed by the two processes, are very prominent.
+In front we find the coronoid fossa, which is less deep than
+that of which we have just spoken.</p>
+
+<div class="figmed"><a name="Fig019" id="Fig019"></a>
+<img src="images/illo052a.png" alt="Fig. 19" width="300" height="343" />
+<p class="caption just">Fig. 19.&mdash;Inferior Extremity of
+the Left Humerus of a Felide
+(Lion).</p>
+
+<p class="subcaption just">1, Epitrochlea; 2, supra-epitrochlear
+foramen.</p></div>
+
+<p>There exists in some mammals an osseous canal, situated
+above the epitrochlea, and known as the <i>supratrochlear
+canal</i> (<a href="#Fig019">Fig. 19</a>). It is bounded by a plate of bone which
+at its middle portion is detached from the shaft of the
+humerus, and blends with the latter at both its extremities.
+The brachial artery and median nerve pass through the
+foramen.</p>
+
+<div class="figmed"><a name="Fig020" id="Fig020"></a>
+<img src="images/illo052b.png" alt="Fig. 20" width="300" height="369" />
+<p class="caption just">Fig. 20.&mdash;Inferior Extremity of
+the Left Human Humerus,
+showing the Presence of a
+Supratrochlear Process.</p>
+
+<p class="subcaption just">1, Epitrochlea; 2, supra-epitrochlear
+process.</p></div>
+
+<p>A similar condition is sometimes found, as an abnormality,
+in man, which presents itself under the following aspect
+(<a href="#Fig020">Fig. 20</a>): an osseous prominence more or less long, in the
+shape of a crochet-needle&mdash;supra-epitrochlear process&mdash;situated
+5 or 6 centimetres above the epitrochlea; the
+summit of this process gives attachment to a fibrous band,
+which is inserted by its other end into the epitrochlea and
+the internal intermuscular aponeurosis. The fibro-osseous
+ring thus formed gives passage to the brachial artery and the<span class="pagenum"><a name="Page_32" id="Page_32">[32]</a></span>
+median nerve, or in case of a premature division of this
+artery to the ulnar branch of the same.<a name="FNanchor_9_9"
+id="FNanchor_9_9"></a><a href="#Footnote_9_9" class="fnanchor">[9]</a></p>
+
+<div class="footnote"><p><a name="Footnote_9_9" id="Footnote_9_9"></a><a href="#FNanchor_9_9"><span class="label">[9]</span></a> For
+further details of this anomaly, see Testut, &#8216;The Epitrochlear
+Process in Man&#8217; (<i>International Journal of Anatomy and Physiology</i>, 1889);
+A. Nicolas, &#8216;New Studies on the Supratrochlear Process in Man&#8217; (<i>Review
+of Biology of the North of France</i>, t. iii., 1890-1891).</p></div>
+
+<p>There is also found in some mammals a perforation of
+the thin plate of bone which, in others, separates the olecranon
+fossa from the coronoid. This perforation is sometimes
+found as an abnormality in the human humerus.</p>
+
+<div class="figmed"><a name="Fig021" id="Fig021"></a>
+<img src="images/illo054.png" alt="Fig. 21" width="500" height="401" />
+<p class="caption just">Fig. 21.&mdash;Skeleton of a Bird (Vulture): Left Surface.</p>
+
+<p class="subcaption just">1, Cranium; 2, face; 3, cervical vertebr&aelig;; 4, spinous processes of
+the dorsal vertebr&aelig;; 5, coccygeal vertebr&aelig;; 6, sternum; 7, keel; 8,
+superior ribs; 9, inferior ribs; 10, clavicle; 11, coracoid bone (for the
+details of the skeleton of the shoulder, see <a href="#Fig018">Fig. 18</a>); 12, humerus; 13,
+radius; 14, ulna; 15, carpus; 16, hand (for details of the skeleton of
+this region, see <a href="#Fig031">Fig. 31</a>); 17, ilium; 18, ischium; 19, pubis (for the details
+of the pelvis, see <a href="#Fig046">Fig. 46</a>); 20, femur; 21, tibia; 22, fibula; 23, osseous
+nodule, which some anatomists think represents the calcaneum; it is
+the sole vestige of the tarsus; 24, metatarsus; 25, foot; 26, first toe (for
+the details of the skeleton of the foot, see <a href="#Fig048">Fig. 48</a>).</p></div>
+
+<p>As does the sternum and the skeleton of the shoulder, the
+humerus of birds presents differences correlated to the
+functions which the thoracic limbs are destined to fulfil.
+Lying on the side of the thorax, directed obliquely downwards
+and backwards (<a href="#Fig021">Fig. 21</a>), it is proportionately longer
+in individuals of powerful flight than in those which fly
+less or not at all. In the vulture it projects beyond the
+posterior part of the pelvis; in the cock it does not even
+reach the anterior border of the same. To these differences
+in length are added differences in volume and in the development
+of the processes which serve for muscular attachment,
+which are more considerable in birds of powerful flight.</p>
+
+<p>The humerus is so placed that the radial border, external
+in man and quadrupeds, looks upwards, with the result that
+the surface of the bone of the arm, which in these latter is
+anterior, in the former looks outwards. The humeral head,
+which is turned forwards and a little inwards, is convex
+and elongated in the vertical direction. Behind and above
+this head is found a crest for the insertion of muscles. It is
+the same for the region below, where there is a tuberosity
+whose inferior surface presents a pretty large opening
+which looks inwards to a fossa from the floor of which a
+number of minute openings communicate with the interior
+of the bone. This is the pneumatic foramen of the humerus.</p>
+
+<p>It is of interest to remember in connection with this subject
+that in birds, in keeping with the conditions of flight, every
+system of organs is adapted to diminish the weight of the
+body. We particularly draw attention to the osseous
+framework, the structure of which is such that the weight<span class="pagenum"><a name="Page_33" id="Page_33">[33]</a></span>
+of the animal is greatly lessened. This condition is secured
+by the pneumaticity. The bone consists of a cover of
+compact tissue, which, instead of enclosing marrow, is
+hollowed out by cavities which contain air, and communicate
+with special pouches, the air-sacs, which are appendages of
+the lungs.<a name="FNanchor_10_10" id="FNanchor_10_10"></a><a href="#Footnote_10_10" class="fnanchor">[10]</a></p>
+
+<div class="footnote"><p><a name="Footnote_10_10" id="Footnote_10_10"></a><a href="#FNanchor_10_10"><span class="label">[10]</span></a>
+The presence of air in the bones does not seem to be always associated
+with the power of flight; as a matter of fact, we find air spaces in the bones
+of some birds which do not fly (E. J. Marey, &#8216;The Flight of Birds,&#8217; Paris,
+1890, p. 51).</p></div>
+
+<p><span class="pagenum"><a name="Page_34" id="Page_34">[34]</a></span>The antibrachial extremity of the humerus is flattened
+from without inwards. It terminates in two articular
+surfaces, which articulate with the radius and ulna.</p>
+
+<p>The olecranon process of the ulna being slightly developed,
+it follows that the olecranon fossa is not large; neither is
+the coronoid.</p>
+
+<h5>General View of the Form of the Forearm and Hand</h5>
+
+<p>We now proceed to the study of the two regions of the
+fore-limbs which present the greatest variety in regard to
+the number of bones and also in regard to form and proportions.
+These two regions are the forearm and the hand.</p>
+
+<p>It is first of all necessary to say that in man, when the
+fore-limb hangs beside the body, and the dorsum of the hand
+looks backwards, the two bones of the forearm are parallel,
+and that this position is known by the name of <i>supination</i>.
+It is also necessary to remember that there is another
+attitude, in which the radius, crossing the ulna, and carrying
+the hand with it, displaces the latter in such a way that the
+palmar surface looks backwards. This second position is
+known as <i>pronation</i>.</p>
+
+<p>Let us now suppose that a man wishes to walk in the
+attitude of a quadruped. It will be necessary, in order that
+his upper limbs, being for the moment anterior ones, may act
+as members of support, to place the forearm in pronation, in
+order that, as is more normal, the hands may rest on the
+ground by their palmar surfaces. In this position the radius,
+being rotated on its own axis at its upper extremity and
+around the ulna in the rest of its extent, shall have its
+inferior extremity situated on the inner side of the corresponding
+extremity of the latter.</p>
+
+<p>Such is the situation of the bones of the forearm and the
+attitude of the hand in quadrupeds. In short, quadrupeds
+have their anterior members in the position of pronation.</p>
+
+<div class="figmed"><a name="Fig022" id="Fig022"></a>
+<img src="images/illo056.png" alt="Fig. 22" width="350" height="344" />
+<p class="caption just">Fig. 22.&mdash;The Human Hand resting for its Whole Extent on its
+Palmar Surface: Left Side, External Surface.</p></div>
+
+<p>The individual whom we have just supposed placed in the
+attitude of a quadruped would be able to maintain this
+position by pressing on the ground more or less extensive
+portions of his hands; the whole palm of the hand may
+be applied to the ground (<a href="#Fig022">Fig. 22</a>); or the fingers
+only&mdash;that<span class="pagenum"><a name="Page_35" id="Page_35">[35]</a></span>
+is to say, the phalanges (<a href="#Fig023">Fig. 23</a>); or the extremities of
+the fingers only&mdash;that is to say, the third phalanges (<a href="#Fig024">Fig. 24</a>).
+This last position, which is certainly difficult to maintain,
+should here be regarded rather as theoretical.</p>
+
+<div class="figmed"><a name="Fig023" id="Fig023"></a>
+<img src="images/illo057a.png" alt="Fig. 23" width="300" height="458" />
+<p class="caption just">Fig. 23.&mdash;The Human Hand resting
+on its Phalanges: Left
+Side, External Surface.</p></div>
+
+<p>We shall meet with each of these modes of support in
+certain groups of animals. Thus, the bear, badger, and the
+majority of rodents, have the paws applied to the ground
+by the whole extent of the palmar surface of the hand, from
+the wrist to the tips of the fingers. They are therefore called
+plantigrade, from the analogy, in this case, of the palm of
+the hand to the plantar surface, or sole of the foot.</p>
+
+<div class="figmed"><a name="Fig024" id="Fig024"></a>
+<img src="images/illo057b.png" alt="Fig. 24" width="125" height="520" />
+<p class="caption just">Fig. 24.&mdash;The Human Hand resting
+on the Tips of some of its
+Third Phalanges: Left Side,
+External View.</p></div>
+
+<p>In others, such as the lion, tiger, panther, cat, wolf, and
+fox, the support is made no longer on the whole extent of
+the palmar surface, but on the corresponding surface of the
+fingers only&mdash;the metacarpus is turned back, and, consequently,
+the wrist&mdash;that is to say, the carpus&mdash;is removed
+from the ground. These are the digitigrades.</p>
+
+<p>Lastly, the ruminants (sheep, oxen, deer, etc.), and also the
+pig, ass, and horse, rest on the third phalanx only. In
+them not only is the metacarpus turned back, but also the
+two first phalanges. The wrist is very far removed from
+the ground. In these animals, the third phalanx is
+enclosed in a case of horn, a nail (the hoof), and because<span class="pagenum"><a name="Page_36" id="Page_36">[36]</a></span>
+the support of the limb is on that nail, the name of unguligrades
+has been given them. Nevertheless, as the point
+of support is on the third phalanx, which is also known by
+the name of phalangette, we are of opinion that, in order to
+specify definitely, although they walk on their fingers, as
+do the digitigrades, the support is provided not by the
+whole extent of those appendages, they might receive
+the name of phalangettigrades.</p>
+
+<p>It is necessary among the ruminants to make an exception
+of the camel and the llama, which are digitigrades.</p>
+
+<p>Just in proportion as the hand is raised from the ground, as
+we have just seen in passing from the plantigrades to the
+digitigrades and unguligrades, the number of bones of that
+region diminishes, the bones of the forearm coalesce, and<span class="pagenum"><a name="Page_37" id="Page_37">[37]</a></span>
+the ulna tends to disappear; the hand becomes less and less
+suitable for grasping, climbing, or digging, so as to form
+an organ exclusively adapted for walking and supporting
+the body.</p>
+
+<p>Thus, the bear (plantigrade) has five digits, and the
+power of performing the movements of supination and
+pronation. Indeed, we know with what facility this animal
+is able to move his paws in every direction, and climb a tree
+by grasping it with his fore-limbs. It is well known,
+however, that no animal except the ape can perform the
+movements of rotation of the radius around the ulna
+with the same facility as man; and that none possesses the
+same degree of suppleness, extent, and variety of movements
+of the forearm and hand.</p>
+
+<p>In the digitigrades there is one finger which is but slightly
+developed, and which is always removed from the ground&mdash;that
+is, the thumb: there is also a little less mobility of the
+radius around the ulna.</p>
+
+<p>In the ungulates the limbs are simply required to
+perform the movements of walking, and form veritable
+columns of support, which become the more solid as
+they are less divided. The bones of the forearm are fused
+together; there is therefore no possibility of rotation
+of the radius around the ulna. The metacarpus is
+reduced to a single piece, which in the horse constitutes
+what is known as the <i>canon</i>. The number of digits
+becomes diminished, so that in ruminants there are not
+more than two, and in the horse but one. We should,
+however, add that, up to the present, we have taken into
+account only perfect digits, those that rest on the ground.
+We shall see further on that there exist supplementary
+digits, but that they are only slightly developed, and are
+represented in some cases by mere osseous spurs; it is this
+fact that has permitted us to ignore them in the general
+study which we have just made.</p>
+
+<p>Because, as we have already said, the unguligrades have
+the inferior extremity of the digit encased in a horny sheath,
+which forms the hoof of the horse and the corresponding
+structures (<i>onglons</i>) in the ox, those animals have been<span class="pagenum"><a name="Page_38" id="Page_38">[38]</a></span>
+placed in a special group, which is based on that peculiarity&mdash;that
+is, the group of ungulate mammals.</p>
+
+<p>The plantigrades and digitigrades, of which the paws
+have their surfaces of support strengthened by an epidermic
+sole and fatty pads, have the free extremities of the third
+phalanges covered on their dorsal surface by nails or claws;
+hence they are named <i>unguiculate</i> mammals.</p>
+
+<p>The bat and birds have the bones of the forearm so
+arranged that the radius cannot rotate around the ulna. This
+is necessary in order that during flight, when the wing is
+being lowered, the radius and hand shall not be able to turn;
+for, if such rotation took place, each stroke of the wing would
+place it in a vertical position, which would occasion a loss of
+resistance incompatible with the effect to be obtained.</p>
+
+<h5>The Forearm</h5>
+
+<p>The skeleton of the forearm in quadrupeds is vertical in
+direction; consequently, it forms with the arm an angle
+open anteriorly; this is well seen on examining the lateral
+surface. If we examine it on its anterior surface, we find
+a slight obliquity directed downwards and inwards. In
+animals in which the bones of the forearm are separate&mdash;that
+is to say, susceptible of supination and pronation&mdash;we
+find a more close resemblance to those of the human
+skeleton. The ulna, the superior extremity of which always
+projects beyond that of the radius, has a shaft which gradually
+narrows from above downwards. Its inferior extremity
+is terminated by a round head in those animals in which the
+ulna is fully developed; in others, as it is atrophied, it ends
+in a thin, long process.</p>
+
+<p>The ulna presents at its superior extremity a posterior
+process, the olecranon, which forms the point of the elbow.
+We find on the anterior surface of the same, another process,
+the coronoid.</p>
+
+<div class="figmed"><a name="Fig025" id="Fig025"></a>
+<img src="images/illo060a.png" alt="Fig. 25" width="250" height="189" />
+<p class="caption just">Fig. 25.&mdash;Superior Extremity of
+the Bones of the Human Forearm:
+Left Side, Superior Surface.</p>
+
+<p class="subcaption just">1, Radius; 2, ulna; 3, olecranon
+process; 4, coronoid process.</p></div>
+
+<div class="figmed"><a name="Fig026" id="Fig026"></a>
+<img src="images/illo060b.png" alt="Fig. 26" width="250" height="279" />
+<p class="caption just">Fig. 26.&mdash;Superior Extremity of
+the Bones of the Forearm of
+the Dog: Left Limb, Superior
+Surface.</p>
+
+<p class="subcaption just">1, Radius; 2, ulna; 3, olecranon
+process; 4, coronoid process.</p></div>
+
+<p>It is necessary to dwell on the relations of these parts.
+In man the head of the radius is situated at the anterior
+part of the external surface of the superior extremity of the
+ulna (<a href="#Fig025">Fig. 25</a>); indeed, the small sigmoid cavity with
+which<span class="pagenum"><a name="Page_39" id="Page_39">[39]</a></span>
+the head articulates is situated on the outer side of the
+coronoid process, and this apophysis is placed in front.
+In the plantigrades and digitigrades the head of the radius
+is placed still more forward, so much so that it is situated
+almost in front of the superior extremity of the ulna (<a href="#Fig026">Fig. 26</a>).
+In the unguligrades it is placed directly in front of this
+latter (<a href="#Fig027">Fig. 27</a>).</p>
+
+<div class="figmed"><a name="Fig027" id="Fig027"></a>
+<img src="images/illo061.png" alt="Fig. 27" width="300" height="376" />
+<p class="caption just">Fig. 27.&mdash;Superior Extremity of the Bones of the Forearm of
+the Horse: Left Limb, Superior Surface.</p>
+
+<p class="subcaption just">1, Radius; 2, ulna; 3, olecranon process; 4, coronoid process.</p></div>
+
+<p>Further, the displacement of the radius is made at the
+expense of the superior extremity of the neighbouring bone;
+the radius appears to appropriate more and more the parts
+which in man belong exclusively to the ulna&mdash;for example,
+the coronoid process. In the plantigrades and the digitigrades
+half of the process still belongs to the ulna and the
+remainder to the radius. In the ungulates&mdash;the horse, for
+example&mdash;the coronoid process belongs to the radius; the
+ulna, situated behind the latter, is correspondingly diminished
+in size.</p>
+
+<p>In brief, when we study this region of the skeleton in
+plantigrades, then in digitigrades, and finally in unguligrades,
+we find a kind of progressive absorption of one of the two
+bones (ulna) by the other (radius), which thus becomes the
+more developed.</p>
+
+<p>It is easy to explain this partial disappearance of the
+ulna. When the forearm is capable of performing the<span class="pagenum"><a name="Page_40" id="Page_40">[40]</a></span>
+movements of pronation and supination, the ulna is completely
+developed, for it is in its small sigmoid cavity that
+the head of the radius revolves, and it is around its inferior
+extremity, the head, that the corresponding extremity of
+the radius turns. But when the movements of rotation
+of the forearm do not exist, the inferior extremity of the
+ulna becomes functionally useless and disappears. As to
+its r&ocirc;le in the movements of the region of the wrist,
+that is nil, for we may remember&mdash;we will observe it again
+when we come to treat of the <a href="#ArticAnterLimbs">articulations</a>&mdash;that the hand
+articulates with the radius alone (radio-carpal articulation);
+this is the reason that, when the forearm possesses the
+fullest mobility, the hand follows the movements which
+that bone makes around the ulna.</p>
+
+<p>It is not so with the articulation at the elbow-joint; there
+it is the ulna, which, with the humerus, forms the essential
+parts (humero-ulnar articulation); its olecranon process<span class="pagenum"><a name="Page_41" id="Page_41">[41]</a></span>
+limits the movement of extension of the forearm. It is for
+this reason that, even in those quadrupeds in which the ulna
+is atrophied, the olecranon process presents a relatively
+considerable degree of development.</p>
+
+<p>We know that on the posterior surface of the inferior
+extremity of the bones of the human forearm are grooves
+in which pass the tendons of the posterior and external<span class="pagenum"><a name="Page_42" id="Page_42">[42]</a></span>
+muscles which, belonging to this region, are directed for
+insertion towards the hand.</p>
+
+<div class="figmed"><a name="Fig028" id="Fig028"></a>
+<img src="images/illo062a.png" alt="Fig. 28" width="300" height="282" />
+<p class="caption just">Fig. 28.&mdash;Inferior Extremity of the Bones of the Forearm of a
+Man: Left Side, Posterior Surface, Position of Supination.</p>
+
+<p class="subcaption just">1, Radius; 2, ulna; A, groove for the long abductor and short extensor
+muscles of the thumb; B, groove for the radial muscles; C, groove for the
+long extensor of the thumb; D, groove for the special extensor of the index
+finger and of the common extensor of the fingers; E, groove for the proper
+extensor of the little finger; F, groove for the posterior ulna.</p></div>
+
+<p>In animals, because of the movement of rotation of the
+radius, the surface of this bone, which is anterior, corresponds
+to the posterior surface of the same in man. (To
+possess a clear conception of this, it is necessary to remember
+that, in this latter, the bones of the forearm are always
+described as in the position of supination; they are thus
+represented in <a href="#Fig028">Fig. 28</a>. The direction of the surfaces of
+the radius is the reverse of that in animals, since the latter
+have the radius always in a state of pronation.)</p>
+
+<div class="figmed"><a name="Fig029" id="Fig029"></a>
+<img src="images/illo062b.png" alt="Fig. 29" width="250" height="322" />
+<p class="caption just">Fig. 29.&mdash;Inferior Extremity of the Bones of the Forearm of the
+Dog: Left Side, Anterior Surface, Normal Position&mdash;that
+is, the Position of Pronation.</p>
+
+<p class="subcaption just">1, Radius; 2, ulna; A, groove for the long abductor and for the short
+extensor of the thumb; B, groove for the radials; D, groove for the long
+extensor of the thumb, the special extensor of the index-finger, and the
+common extensor of the fingers; E, groove for the special extensor of the
+little finger.</p></div>
+
+<p>Consequently it is on the anterior surface of the bone that
+we find the grooves concerning which it is necessary to give
+some details. Regarding them in passing from the radius
+towards the ulna, those grooves give passage to the tendons
+of the muscles whose names occupy the columns on <a href="#Page_43">p. 43</a>.
+The letters which are referred to each serve to define their
+order, and to facilitate reference to <a href="#Fig028">Figs. 28</a>, <a href="#Fig029">29</a>, and <a href="#Fig030">30</a>.</p>
+
+<div class="figmed"><a name="Fig030" id="Fig030"></a>
+<img src="images/illo063.png" alt="Fig. 30" width="300" height="245" />
+<p class="caption just">Fig. 30.&mdash;Inferior Extremity of the Bone of the Forearm of the
+Horse: Left Side, Anterior Surface.</p>
+
+<p class="subcaption just">1, Radius; A, groove for the long abductor and the short extensor of
+the thumb; B, groove for the radials; D, groove for the common extensor
+of the digits; E, groove for the special extensor of the little finger.</p></div>
+
+<p>We should mention that the groove E is situated, both in
+man and in the dog, at the level of the inferior radio-ulnar
+articulation; but that in the horse, as the ulna does not
+exist at that level, the groove is situated on the external
+surface of the inferior extremity of the radius. It is necessary
+to add that, in some horses, the ulna is, nevertheless,<span class="pagenum"><a name="Page_43" id="Page_43">[43]</a></span>
+represented in this region by a tongue-like process of bone;
+and in such cases the groove is situated in front of this
+process, at the level of the line of coalescence, which there
+represents the articulation.</p>
+
+<table class="fsize80" style="margin: 2em 5%;" summary="Table page 43">
+
+<tr class="bt bb">
+<td colspan="2" class="center padl1 padr1 br"><span class="smcap">Man.</span></td>
+<td colspan="2" class="center padl1 padr1 br"><span class="smcap">Dog.</span></td>
+<td colspan="2" class="center padl1 padr1"><span class="smcap">Horse.</span></td>
+</tr>
+
+<tr>
+<td class="left top padl1 padr1">A.</td>
+<td class="left top padr1 br" style="width: 30%;">Long abductor of the thumb, and short extensor of the thumb.</td>
+<td class="left top padl1 padr1">A.</td>
+<td class="left top padr1 br" style="width: 30%;">Long abductor of the thumb and short extensor of the thumb united as one muscle,
+<i>the oblique extensor of the metacarpus</i>.<a name="FNanchor_11_11" id="FNanchor_11_11"></a><a href="#Footnote_11_11"
+class="fnanchor">[11]</a></td>
+<td class="left top padl1 padr1">A.</td>
+<td class="left top padr1" style="width: 30%;"><i>Oblique extensor of the metacarpus</i>, the homologue of the long abductor of the
+thumb and the short extensor of the thumb, united as one muscle.</td>
+</tr>
+
+<tr>
+<td class="left top padl1 padr1">B.</td>
+<td class="left top padr1 br">First and second external radials (<i>extensor carpi radialis longior</i> and <i>brevior</i>).</td>
+<td class="left top padl1 padr1">B.</td>
+<td class="left top padr1 br">The two radials blended superiorly, distinct inferiorly; this is <i>the anterior extensor of the
+metacarpus</i>.</td>
+<td class="left top padl1 padr1">B.</td>
+<td class="left top padr1">The radials represented by a single muscle, <i>the anterior extensor of the metacarpus</i>.</td>
+</tr>
+
+<tr>
+<td class="left top padl1 padr1">C.</td>
+<td class="left top padr1 br">Long extensor of the thumb.</td>
+<td class="left top padl1 padr1">C.</td>
+<td class="left top padr1 br">Long extensor of the thumb and special extensor of the index finger united superiorly. These muscles pass
+in the following groove.</td>
+<td class="left top padl1 padr1">C.</td>
+<td class="left top padr1">The long extensor of the thumb and the special extensor of the index are absent.</td>
+</tr>
+
+<tr>
+<td class="left top padl1 padr1">D.</td>
+<td class="left top padr1 br">Special extensor of the index finger and the common extensor of the fingers.</td>
+<td class="left top padl1 padr1">D.</td>
+<td class="left top padr1 br">Common extensor of the digits and the two preceding muscles.</td>
+<td class="left top padl1 padr1">D.</td>
+<td class="left top padr1"><i>Anterior extensor of the phalanges</i>, the homologue of the common extensor of the digits.</td>
+</tr>
+
+<tr>
+<td class="left top padl1 padr1">E.</td>
+<td class="left top padr1 br">Special extensor of the little finger.</td>
+<td class="left top padl1 padr1">E.</td>
+<td class="left top padr1 br"><i>Extensor of the third, fourth, and fifth digits</i>, or <i>the lateral extensor of the digits</i>, the
+homologue of the special extensor of the little finger.</td>
+<td class="left top padl1 padr1">E.</td>
+<td class="left top padr1">Lateral extensor of the phalanges, the homologue of the special extensor of the little finger.</td>
+</tr>
+
+<tr class="bb">
+<td class="left top padl1 padr1">F.</td>
+<td class="left top padr1 br">The posterior ulnar (<i>extensor carpi ulnaris</i>).</td>
+<td colspan="4" class="left top padl1 padr1">There does not exist on the forearm a groove for the posterior ulnar muscle, or <i>external
+flexor of the metacarpus</i>.</td>
+</tr>
+
+</table>
+
+<div class="footnote"><p><a name="Footnote_11_11" id="Footnote_11_11"></a><a href="#FNanchor_11_11"><span class="label">[11]</span></a>
+The words printed in italics are the names used in veterinary
+anatomy.</p></div>
+
+<p>It is also useful to note, with reference to the groove F,
+in which passes, in man, the tendon of the posterior ulnar
+muscle, that, when the forearm is in pronation, the radius
+alone being displaced, we can only see this groove on the
+surface which looks backwards; and that it is then separated
+from the groove which contains the tendon of the special
+extensor of the little finger by an interval equal to the thickness<span class="pagenum"><a name="Page_44" id="Page_44">[44]</a></span>
+of the head of the ulna.<a name="FNanchor_12_12" id="FNanchor_12_12"></a><a href="#Footnote_12_12" class="fnanchor">[12]</a> When
+the forearm is supinated,
+the two grooves are found, on the other hand, one
+beside the other: and the tendons which they contain are
+very naturally in contact.</p>
+
+<div class="footnote"><p><a name="Footnote_12_12" id="Footnote_12_12"></a><a href="#FNanchor_12_12"><span class="label">[12]</span></a>
+&Eacute;douard Cuyer, &#8216;Shape of the Region of the Wrist in Supination and
+Pronation&#8217; (<i>Bulletin de la Soci&eacute;t&eacute; d&#8217;Anthropologie</i>, Paris, 1888).</p></div>
+
+<p>In birds the forearm is flexed on the arm, and the latter
+being directed downwards and backwards, the former is,
+consequently, directed upwards and forwards. Further,
+because of the position of the humerus, which, as we mentioned
+on <a href="#Page_32">p. 32</a>, has its inferior extremity so turned that
+the surface which is anterior in man becomes external, the
+radius, instead of being outside the ulna, is placed above it.
+This latter is larger than the radius, but its olecranon process
+is very slightly developed.</p>
+
+<h5>The Hand</h5>
+
+<p>The hand in animals, as in man, is formed of three parts&mdash;the
+carpus, metacarpus, and fingers. In man, the forearm
+and the hand being described in the position of supination;
+the bones of the carpus are named in passing from the most
+external to the most internal&mdash;that is to say, from that
+which corresponds to the radial side of the forearm to that
+which corresponds to the ulnar side. In animals in which,
+as we know, but it is not unprofitable to repeat, the hand
+is in pronation, the radial side of the forearm being placed
+inside, we enumerate the carpal bones in counting the
+most internal as the first; this is the only method which
+permits us, in taking our point of departure from the human
+skeleton as our standard, to recognise the homologies of the
+bones of the carpal region.</p>
+
+<p>These bones, eight in number, are arranged in two transverse
+rows, of which one, the first, is superior or anti-brachial;
+the other, the second, is inferior or metacarpal.
+Each of these rows contains four bones. Considered in
+the order we have indicated above&mdash;that is to say, proceeding
+from the radial to the ulnar side&mdash;they are thus named:
+scaphoid, semilunar, cuneiform, and pisiform, in the first<span class="pagenum"><a name="Page_45" id="Page_45">[45]</a></span>
+row; trapezium, trapezoid, os magnum, and unciform, in
+the second. The number of these bones is not the same
+in all animals on account of the coalescence or absence of
+some. In each row the bones are placed side by side, with
+the exception of the pisiform, which being placed on the
+palmar surface of the cuneiform, produces a small projection
+in man, but a very pronounced one in quadrupeds.</p>
+
+<p>The pisiform is called the <i>hooked bone</i> in some veterinary
+anatomies. If we consider the hook which it forms, we
+may recognise that the name is appropriate; but from
+the point of view of comparison with the human carpus,
+the name is unfortunate, for it creates confusion between
+the true pisiform (the fourth bone in the upper row), and
+the last bone in the lower row, which is the veritable unciform
+bone. We do not here seek for similarity of form, but
+homology of regions; and it is only by using the same
+names to denote the same things that we can succeed in
+determining such homology.</p>
+
+<p>Taken as a whole, the bones of the carpus form a mass
+which, by its superior border, articulates with the bones
+of the forearm, and by its inferior border is in relation with
+the metacarpal region. Its dorsal surface (anterior in
+quadrupeds) is slightly convex; its palmar surface (posterior
+in quadrupeds) is excavated, and forms a groove in
+which pass the tendons of the flexors of the fingers. This
+last, in man, has the appearance of a gutter, because of the
+prominences caused by the projection of the internal and
+external bones beyond their fellows.</p>
+
+<p>In quadrupeds the palmar groove is especially determined
+by the pisiform bone, of which we have just mentioned the
+great development.</p>
+
+<p>The region occupied by the carpus, in the unguligrades,
+is known as the <i>knee</i>; it would have been more appropriately
+named had it been called the <i>wrist</i>.</p>
+
+<p>The number of the metacarpal bones in mammals never
+exceeds five, but it often falls below it; the same is true
+for the digits. The first are generally equal in number to
+the latter; an exception is met with in ruminants, whose
+two metacarpals coalescing soon after birth, form but<span class="pagenum"><a name="Page_46" id="Page_46">[46]</a></span>
+one bone; this, the <i>canon</i> bone, articulates with two
+digits.</p>
+
+<p>The number of metacarpals and digits diminishes in proportion
+as the limbs cease to be organs of prehension, and
+become more exclusively organs of support and locomotion.</p>
+
+<p>The number of phalanges is two for the thumb and three
+for each of the other digits; except in the cetaceans, in
+which they are more numerous.</p>
+
+<p>In the bat, the metacarpals and phalanges are very long,
+and form the skeleton of the wing; these phalanges are
+not furnished with nails; the thumb, which is very short,
+is alone provided with one (<a href="#Fig008">Fig. 8</a>).</p>
+
+<p>With regard to the relative dimensions of the bones of
+the metacarpus, it is necessary to remember that, in the
+human being, the second metacarpal is the longest; then,
+in the order of decrease, come the third, fourth, fifth, and
+first. In quadrupeds we shall also find differences in
+length (see the chapter relating to the anterior limbs in
+certain animals), but the order of decrease is not always
+that which we have just mentioned.</p>
+
+<p>In man the articular surface, situated at the inferior extremity
+of each of the metacarpals, is rounded, and is
+called the head. This allows the first phalanx, which is
+in relation with that surface, to be displaced in every
+direction; indeed, this phalanx can not only be flexed and
+extended, but it can also be moved laterally; this latter
+movement allows of the fingers being separated and drawn
+together.</p>
+
+<p>In quadrupeds which can only perform the movements of
+flexion and extension of the digits&mdash;for example, the horse&mdash;the
+inferior extremity of the metacarpal has not a rounded
+head of a regular outline; it is marked by a prominent
+median crest, directed from before backwards, so that the
+articular surfaces, which fit more exactly, form a sort of hinge
+which allows of backward and forward movements only, and
+permits no lateral displacement. In man, at the level of the
+inferior extremity of the first metacarpal, in the vicinity of the
+articulation of this bone with the first phalanx of the thumb,
+we find two sesamoid bones&mdash;small bones developed in<span class="pagenum"><a name="Page_47" id="Page_47">[47]</a></span>
+the fibrous tissue which surrounds the articulation. We
+also meet with such structures, but more rarely, at the level
+of the corresponding articulation of the index and auricular
+digits; and, more rarely still, at those of the middle and
+ring fingers. In quadrupeds, these bones are normally
+developed, and we shall see afterwards that in some
+animals, as they reach a considerable size, they are able to
+influence the external outlines; we shall see this, for example,
+in the horse.</p>
+
+<div class="figmed"><a name="Fig031" id="Fig031"></a>
+<img src="images/illo068.png" alt="Fig. 31" width="450" height="248" />
+<p class="caption just">Fig. 31.&mdash;Skeleton of the Superior Limb of a Bird (Vulture):
+Left Side, External Surface.</p>
+
+<p class="subcaption just">1, Humerus; 2, radius; 3, ulna; 4, radial bone of the carpus; 5, ulnar
+bone of the carpus; 6, first metacarpal; 7, second metacarpal; 8, third
+metacarpal; 9, first digit, the homologue of the thumb; 10, first phalanx
+of the second digit; 11, second phalanx of the second digit; 12, third
+digit.</p></div>
+
+<p>The hand, in birds, is directed obliquely downwards and
+backwards (<a href="#Fig031">Fig. 31</a>). For the better understanding of its
+position in relation to the forearm, we should remember
+that this latter, as we have described (<a href="#Page_44">p. 44</a>), directed
+obliquely upwards and forwards, has the radius placed
+above the ulna; the hand being oblique in the opposite
+direction and placed under the forearm is, by this arrangement,
+inclined towards the ulnar border of the latter.</p>
+
+<div class="figmed"><a name="Fig032" id="Fig032"></a>
+<img src="images/illo069.png" alt="Fig. 32" width="450" height="330" />
+<p class="caption just">Fig. 32.&mdash;Superior Limb of the Human Being, the Different
+Segments being placed in the Attitude which the Corresponding
+Parts occupy in Birds: Left Side, External Surface.</p></div>
+
+<p>For the rest, in order to be able to distinguish readily the
+corresponding parts in the hand of a bird and that of a man,
+we merely have to place the human forearm obliquely, in a
+direction upwards and forwards (<a href="#Fig032">Fig. 32</a>), the radius being
+above; this position we can obtain by semi-pronation;<span class="pagenum"><a name="Page_48" id="Page_48">[48]</a></span>
+then, to incline strongly the hand downwards and backwards,
+moving the ulnar border of the hand towards
+the ulna; the thumb is then anterior, the little finger
+posterior, and the palm of the hand is turned towards the
+trunk.</p>
+
+<p>The carpus in birds is formed by two bones only, with
+which the skeleton of the forearm articulates. That
+which is in contact with the radius is called the <i>radial bone
+of the carpus</i>; and that with which the ulna articulates
+is named the <i>ulnar bone</i>.</p>
+
+<p>The metacarpus is formed of three bones; the first,
+which is very short, is fused at its superior extremity with
+the adjoining one; this latter and the third, both longer than
+the first, but of unequal size, are fused at their extremities.
+The metacarpal, which articulates with the radial bone of
+the carpus, is larger than the one which is in line with the
+ulna. To the metacarpus succeed three digits, of which the
+central is the longest, and is formed of two phalanges; the
+other two are formed each by a small, stylet-shaped bone.
+The middle finger, situated on the prolongation of the
+metacarpal, which articulates with the radial bone of the
+carpus, has its first phalanx large and flattened transversely;
+this phalanx seems to have been formed by the union of
+two bones of unequal development; the second phalanx<span class="pagenum"><a name="Page_49" id="Page_49">[49]</a></span>
+is styloid in form. As to the other two fingers, they are
+placed, one in front and the other behind; the first, which
+articulates with the short metacarpal, fused at its upper
+end with the principal bone of the metacarpus, in position
+represents the thumb. The other, which is the third
+finger, articulates with the inferior extremity of the thinnest
+bone of the metacarpus; it is sometimes closely united
+to the corresponding border of the first phalanx of the large&mdash;that
+is to say, of the median&mdash;digit.</p>
+
+<h5><a name="LongerHumerus" id="LongerHumerus"></a>The Anterior Limbs in Certain Animals</h5>
+
+<p><b>Plantigrades: Bear</b> (<a href="#Fig033">Fig. 33</a>).&mdash;The scapula of the bear
+approaches in shape to a trapezium, of which the angles
+have been rounded off. The anterior border (cervical) is
+strongly convex in the part next the glenoid cavity. The
+junction of the superior (spinal) and the cervical border
+forms almost a right angle, the summit of which corresponds
+to the origin of the spine. At its posterior angle
+there is a prominence, directed downwards, the surface of
+which is hollowed and is separated from the infraspinous
+fossa by a crest, so that at this level a third fossa is added to
+the infraspinous one. The neck of the scapula is but slightly
+marked. The acromion is prominent, and projects a little
+beyond the glenoid cavity.</p>
+
+<p class="pagenumpic"><a name="Page_50" id="Page_50">[50]</a></p>
+
+<div class="figlarge"><a name="Fig033" id="Fig033"></a>
+<img src="images/illo071.png" alt="Fig. 33" width="600" height="373" />
+<p class="caption just">Fig. 33.&mdash;Skeleton of the Bear: Left Lateral Surface.</p>
+
+<p class="subcaption just">1. Cranium; 2, face; 3, atlas; 4, axis; 5, seventh cervical vertebra; 6, first dorsal vertebra; 7, fourteenth and
+last dorsal vertebra; 8, lumbar vertebr&aelig;; 9, sacrum; 10, coccygeal vertebr&aelig;; 11, sternum; 12, ninth and last
+sternal rib; 13, costal cartilages; 14, acromion process; 15, third fossa on the external surface of the scapula;
+16, great tuberosity of the humerus; 17, musculo-spiral groove; 18, epicondyle; 19, radius; 20, ulna; 21,
+olecranon process; 22, carpus; 23, pisiform; 24, metacarpus; 25, phalanges; 26, ilium, external fossa;
+27, pubis; 28, tuberosity of the ischium; 29, obturator foramen; 30, great trochanter of the femur; 31,
+condyles of the femur; 32, patella, or knee-cap; 33, anterior tuberosity of the tibia; 34, fibula; 35, tarsus;
+36, calcaneum, or heel-bone; 37, metatarsus; 38, phalanges.</p></div>
+
+<p>The clavicle is rudimentary, but, as an example of the
+complete development of this bone in plantigrade quadrupeds,
+we may cite the marmoset.</p>
+
+<p>The humerus is furnished at its superior extremity with a
+large tuberosity, wide, and situated in front of the head of
+the bone; the effect of this is that the bicipital groove is
+internal. As in man, the great tuberosity does not reach so
+high as the humeral head, but it approaches more nearly
+to that level. The deltoid impression is very extensive,
+and descends pretty far down on the body of the bone. The
+epitrochlea is prominent; the epicondyle is surmounted by
+a well-marked crest, curved and flexuous in outline.</p>
+
+<p>The articular surface, which is in contact with the
+radius, is not a regularly formed condyle; it is a little<span class="pagenum"><a name="Page_51" id="Page_51">[51]</a></span>
+flattened on its anterior surface, and presents at this level
+a slight depression which corresponds to a small eminence
+on the anterior aspect of the superior extremity of the
+radius. The surface which articulates with the ulna, viewed
+on its anterior aspect, has the shape of a slightly-marked
+trochlea; except at the level of the internal lip, which, as
+in man, descends lower than the surface for articulation
+with the radius (condyle). Behind, the trochlea is more
+clearly defined.</p>
+
+<p>The bear possesses a considerable power of rotation of
+the radius; the bones of the forearm are joined only at
+their extremities, while in the remainder of their extent
+they are widely separated. The ulna terminates below in
+a head and a styloid process; these articulate with the two
+last bones of the first row of the carpus&mdash;viz., the cuneiform
+and pisiform. The bones of the carpus are seven
+in number, the scaphoid and the semilunar being fused
+together.</p>
+
+<p>The metacarpals, five in number, differ very little from
+one another in regard to length, though they increase in
+size from the first to the fifth; this may be demonstrated
+by looking at the palmar surface of the hand. It is the
+reverse of that which we find in man, for the fifth metacarpal
+is the thickest of all, and the first is the most
+slender.</p>
+
+<p>At the level of each metacarpo-phalangeal articulation
+are two sesamoid bones.</p>
+
+<p>The third digit is the longest. The terminal phalanges
+present two very different portions: one, the anterior, is
+curved and pointed; it serves to support the nail, whose
+shape it assumes; the other, posterior, forms a sort of
+sheath into which the base of the nail is received.</p>
+
+<p>The inferior portion of the posterior surface of this latter
+part articulates with the second phalanx in the case of
+each of the last four digits, but with the first phalanx in
+the case of the thumb.</p>
+
+<p class="pagenumpic"><a name="Page_52" id="Page_52">[52]</a></p>
+
+<div class="figlarge"><a name="Fig034" id="Fig034"></a>
+<img src="images/illo073.png" alt="Fig. 34" width="600" height="421" />
+<p class="caption just">Fig. 34.&mdash;Skeleton of the Dog: Left Lateral Surface.</p>
+
+<p class="subcaption just">1, Cranium; 2, face; 3, atlas; 4, axis; 5, seventh cervical vertebra; 6, thirteenth
+and last dorsal vertebra; 7, lumbar vertebr&aelig;;
+8, sacrum; 9, coccygeal vertebr&aelig;; 10, anterior extremity of the sternum; 11, xiphoid appendix; 12, ninth and last sternal
+rib; 13, costal cartilages; 14, spinal border of the scapula; 15, supraspinous fossa of the scapula; 16, infraspinous fossa of the
+scapula; 17, great tuberosity of the humerus; 18, deltoid impression; 19, musculo-spiral groove; 20, olecranon process; 21,
+radius; 22, carpus; 23, pisiform; 24, metacarpus; 25, sesamoid bones; 26, phalanges; 27, ilium, iliac crest; 28, pubis;
+29, tuberosity of the ischium; 30, great trochanter of the femur; 31, patella, or knee-cap; 32, anterior tuberosity of the tibia;
+33, fibula; 34, tarsus; 35, calcaneum, or heel-bone; 36, metatarsus; 37, sesamoid bones; 38, phalanges.</p></div>
+
+<p><b>Digitigrades: Cat</b>, <b>Dog</b> (<a href="#Fig034">Fig. 34</a>).&mdash;In these animals the
+anterior (cervical) border of the scapula is convex; the
+posterior (axillary) border is straight or slightly concave.
+The supraspinous and infraspinous foss&aelig; are of equal extent
+(<a href="#Fig035">Figs. 35</a> and <a href="#Fig036">36</a>). The neck is short. The spine of the
+scapula becomes more and more prominent towards its
+inferior extremity, where it ends in a twisted and inflexed
+portion, which represents the acromion process; this process
+terminates at the level of the glenoid cavity. The
+coracoid process is represented by a small tubercle, slightly<span class="pagenum"><a name="Page_54" id="Page_54">[54]</a></span>
+curved inwards; this tubercle is situated above the glenoid
+cavity, at the inferior part of the cervical border.</p>
+
+<p class="pagenum"><a name="Page_53" id="Page_53">[53]</a></p>
+
+<div class="figmed"><a name="Fig035" id="Fig035"></a>
+<img src="images/illo074a.png" alt="Fig. 35" width="300" height="313" />
+<p class="caption just">Fig. 35.&mdash;Scapula of the Dog: Left Side, External Surface.</p>
+
+<p class="subcaption just">1, Posterior or axillary border; 2, superior or spinal border; 3, anterior
+or cervical border; 4, spine of scapula; 5, coracoid process; AA&#8242;, length
+of spinal border.</p></div>
+
+<div class="figmed"><a name="Fig036" id="Fig036"></a>
+<img src="images/illo074b.png" alt="Fig. 36" width="300" height="224" />
+<p class="caption just">Fig. 36.&mdash;Left Scapula of the Cat: External Surface.</p>
+
+<p class="subcaption just">1, Posterior or axillary border; 2, superior or spinal border; 3, anterior
+or cervical border; 4, spine of the scapula; 5, coracoid process; AA&#8242;,
+length of the spinal border.</p></div>
+
+<p>In the dog, the posterior angle, formed by the junction
+of the axillary and the superior (spinal) borders, is obtuse;
+the spine rises perpendicularly from the surface of the bone.
+The width of the scapula, measured at the level of the
+spinal border (from A to A&#8242;, <a href="#Fig035">Fig. 35</a>), equals about half the
+length of the spine. We must, however, make an exception
+for the turnspit dog, in which the superior border
+equals three-fourths of that length. The scapula is, in this
+case, of a more compact type; it is broader, but shorter.
+In the cat, the anterior outline of the scapula, formed by
+the union of the cervical border and the corresponding half
+of the spinal, is more convex; the posterior angle is not
+obtuse, as in the dog. The spine is bent slightly downwards
+and backwards; before terminating in the acromion
+process it presents a triangular projection, the apex
+of which is directed downwards. The tubercle which represents
+the coracoid process is curved inwards more
+strongly than that of the dog, thus resembling more
+closely the appearance of this process in the human
+being.</p>
+
+<p>All proportions considered, the scapula of the cat is
+broader than that of the dog; its width, measured along
+the length of its spinal border (from A to A&#8242;, <a href="#Fig036">Fig. 36</a>),
+equals three-fourths of the length of the spine.</p>
+
+<p>The clavicle is rudimentary; it is, however, better developed
+in the cat than in the dog. The clavicle of the cat
+is represented by a small, elongated bone, curved in outline,
+the convexity being turned forward; it is united to
+the acromion and the sternum by ligamentous fibres; that
+of the dog is merely a scale-like osseous plate situated on
+the posterior surface of a muscle of this region (see <a href="#Fig016">Figs. 16</a>
+and <a href="#Fig017">17</a>).</p>
+
+<p>The humerus is long and twisted in the shape of an S. The
+inferior articular surface has the form of a simple pulley,
+for the condyle is very slightly marked. The internal part
+of this articular surface descends lower than the external;
+this condition resembles that found in the human being,<span class="pagenum"><a name="Page_55" id="Page_55">[55]</a></span>
+where the inner lip of the trochlea is lower than the
+condyle.</p>
+
+<p>In the dog, the olecranon fossa communicates with the
+coronoid by an opening.</p>
+
+<p>In the cat, there is a supra-epitrochlear canal (see <a href="#Fig019">Fig. 19</a>),
+but no olecranon perforation.</p>
+
+<p>The bones of the forearm articulate at their extremities.
+The body of the radius is united to the body of the ulna by
+a short, thick, interosseous ligament; the fibres of this
+ligament, though short, do not prevent the production of
+some movements at the articulations of the bones.</p>
+
+<p>The radius so crosses the ulna that above, it is in
+front and external to the latter, while below, it is internal.
+This bone is flattened from front to back, and slightly
+convex anteriorly. Its superior extremity is formed,
+externally, of a portion which represents the head of the
+radius in man; internally, by another portion which
+represents half of the coronoid process of the ulna, which,
+in the human being, belongs exclusively to the latter (see
+<a href="#Page_39">p. 39</a>, the encroachment of the radius on the ulna). This
+extremity is surrounded with a vertical articular surface
+which is placed in contact with a small cavity which is
+hollowed out on the ulna (the lesser sigmoid cavity); and
+presents at its superior aspect a surface which articulates
+with the inferior extremity of the humerus. The shaft of
+the bone has on its internal border rugosities analogous to
+the imprint of the pronator radii teres of the human skeleton;
+these rugosities, indeed, give insertion to a muscle of the
+same function, and bearing the same name. The inferior
+extremity, broader than the superior, is hollowed on its
+external aspect by a small cavity which receives the inferior
+extremity of the ulna; its inferior surface (concave)
+articulates with the carpus; its anterior surface (the homologue
+of the posterior surface of the corresponding extremity
+of the human radius) presents grooves which serve for
+the passage of the tendons of the muscles which pass
+from the forearm to the back of the hand. (For the
+names of the muscles whose tendons pass in these grooves,
+see <a href="#Fig029">Fig. 29</a>.)</p>
+
+<p><span class="pagenum"><a name="Page_56" id="Page_56">[56]</a></span>The ulna is furnished at its superior extremity with an
+olecranon process, which is more prominent than that of
+the human ulna; this process is compressed laterally, and
+its internal surface is hollowed; there we also find a great
+sigmoid cavity, and a coronoid process situated at the
+internal part of the anterior surface, a process which, as we
+have previously shown, it shares with the radius.</p>
+
+<p>The shaft of the bone, prismatic and triangular, diminishes
+in thickness as it approaches the lower extremity, which
+articulates with the corresponding extremity of the radius.
+In the dog, the ulna terminates inferiorly in a blunt point,
+without enlargement, analogous to the head of the human
+ulna; in the cat, by a head which is prolonged into a
+styloid process, by which it articulates with a portion of
+the carpus.</p>
+
+<p>The carpus consists of seven bones&mdash;three in the superior
+row and four in the inferior. In the superior row the
+scaphoid and semilunar bones are fused together. The
+pisiform is elongated and expanded at its two extremities;
+it forms a prominence which, directed backwards, projects
+beyond the level of the other bones of this region.</p>
+
+<p>The metacarpal bones are five in number; they are enumerated
+from within outwards; they articulate with the carpus
+and with each other. The inferior extremity of each metacarpal
+bone presents the form of a condyle in front; and is
+divided behind so as to form two lateral condyles, which are
+separated by a median crest; on these posterior condyles
+are applied two small sesamoid bones. The metacarpal
+bone of the thumb is very short; the third and fourth are
+the longest. The metacarpus, as a whole, is directed vertically.</p>
+
+<div class="figmed"><a name="Fig037" id="Fig037"></a>
+<img src="images/illo078.png" alt="Fig. 37" width="400" height="337" />
+<p class="caption just">Fig. 37.&mdash;Skeleton of the Finger of a Felide (Lion): Left Side,
+Internal Surface.</p>
+
+<p class="subcaption just">1, Metacarpus; 2, sesamoid bones; 3, first phalanx; 4, second phalanx;
+5, third phalanx; 6, gutter for the reception of the base of the nail; 7,
+prominent osseous crest formed to lodge in the concavity of the nail.</p></div>
+
+<p>The phalanges are three in number for each finger, except
+the thumb, which has but two. The first phalanx, directed
+almost horizontally forwards, is the longest; the second is
+directed downwards and forwards; the third consists of
+two portions: a posterior part, which forms a sort of sheath
+into which the base of the nail is received; and an anterior,
+conical in form, and curved in crochet shape, which forms a
+support for the nail (<a href="#Fig037">Fig. 37</a>).</p>
+
+<p><span class="pagenum"><a name="Page_57" id="Page_57">[57]</a></span>The third and fourth digits are the longest; the second
+and fifth are of equal length; the thumb is the shortest;
+it does not touch the ground, and does not even reach the
+articulation of the metacarpal bone and first phalanx of the
+second finger.</p>
+
+<p>In the cat, the metacarpal bone of the thumb, although
+shorter than any of the others, is quite as thick. The
+third digit is a little longer than either the second or
+fourth. In animals of this genus, the claws, in the condition
+of repose, are retracted, and removed from the
+ground; this prevents their being worn, and thus preserves
+their sharpness. At such times the third phalanx
+is received into a groove which is found on the external
+surface of the second phalanx. In the dog, the claws are
+not tractile.</p>
+
+<p class="pagenumpic"><a name="Page_58" id="Page_58">[58]</a></p>
+
+<div class="figlarge"><a name="Fig038" id="Fig038"></a>
+<img src="images/illo079.png" alt="Fig. 38" width="600" height="344" />
+<p class="caption just">Fig. 38.&mdash;Skeleton of the Pig: Left Lateral Surface.</p>
+
+<p class="subcaption just">1, Cranium; 2, face; 3, atlas; 4, axis; 5, seventh cervical vertebra;
+6, first dorsal vertebra; 7, fourteenth and last dorsal
+vertebra; 8, lumbar vertebr&aelig;; 9, sacrum; 10, coccygeal vertebr&aelig;; 11, anterior extremity of the sternum; 12, xiphoid
+appendix; 13, seventh and last sternal rib; 14, costal cartilage; 15, cartilage of prolongation of the scapula; 16, great
+tuberosity of the humerus; 17, olecranon process; 18, radius; 19, ulna; 20, pisiform; 21, metacarpus; 22, phalanges of
+the two great toes; 23, phalanges of the external toe; 24, ilium; 25, pubis; 26, tuberosity of the ischium; 27, great
+trochanter; 28, knee-cap; 29, anterior tuberosity of the tibia; 30, fibula; 31, tarsus; 32, calcaneum; 33, metatarsus;
+34, phalanges of the two great toes; 35, phalanges of the external toe.</p></div>
+
+<p><span class="pagenum"><a name="Page_59" id="Page_59">[59]</a></span><b>Unguligrades</b>:
+<b>Pig</b> (<a href="#Fig038">Fig. 38</a>).&mdash;The scapula is markedly
+narrowed in the region above the glenoid cavity. The
+spine is atrophied at both its extremities, so that at its
+inferior part we do not find the acromion process. In
+its middle portion the spine is prominent, and presents a
+triangular process which turns backwards, overlapping a
+part of the infraspinous fossa; this latter is much larger
+than the supraspinous. The spinal border is surmounted
+by the cartilage of prolongation, the superior margin of
+which is convex; this cartilage extends posteriorly beyond
+the posterior (axillary) border of the bone.</p>
+
+<p>The small tuberosity of the superior extremity of the
+humerus is but slightly developed; the great tuberosity, on
+the contrary, is very large. The bicipital groove is situated
+internal to this. The deltoid impression is scarcely marked.</p>
+
+<p>The forearm is short, directed obliquely downwards and
+inwards, thus forming with the hand an angle, of which the
+apex is directed inwards. The two bones of the forearm
+are strongly bound to one another by an interosseous ligament,
+which is formed of very short fibres. The radius
+appropriates, at its superior extremity, the coronoid
+process of the ulna. The latter is, notwithstanding, well
+developed in the rest of its extent; it has a flattened
+shaft which almost completely overlaps the posterior
+surface of the radius; its inferior extremity reaches to the
+carpus.</p>
+
+<p>The carpus is formed of eight bones&mdash;four in the superior
+row, and four in the inferior. The third bone of the
+superior row (cuneiform) is more in contact with the ulna
+than with the radius.</p>
+
+<p>There are but four metacarpal bones; there is no metacarpal
+of the thumb. The two median metacarpal bones
+are the longest; they are those which correspond to the
+digits which alone touch the ground. The internal digit
+and the external one are thin and short; they are functionless,
+as a rule, taking no part in supporting the limbs on
+the ground. Notwithstanding this, they are formed, as
+the other digits, of a number of phalanges, which give
+them the semblance of perfect digits. (We shall soon see
+that in certain animals there exist digits which, being incomplete
+with regard to the numbers of their constituent
+bones, more accurately merit the name of imperfect
+digits.)</p>
+
+<p>The third phalanges are each enclosed in a horny hoof,
+to which the name of <i>onglon</i> has been given.</p>
+
+<p>We have already drawn attention to the smaller lateral<span class="pagenum"><a name="Page_60" id="Page_60">[60]</a></span>
+digits, and noted the general fact that they do not come in
+contact with the ground. It is necessary to modify this
+statement by adding that under certain conditions they
+give a slight amount of support; for example, when the
+individual is the subject of excessive obesity, the limbs
+yield under the weight, and the nails of the lateral digits
+may touch the ground.</p>
+
+<p>A similar fact may be noticed in pigs of ordinary bulk at
+the moment when, during walking, each of the fore-limbs
+commences to bear the weight&mdash;that is to say, when it is
+directed obliquely downwards and forwards; then all the
+digits are in contact with the ground.</p>
+
+<p class="pagenumpic"><a name="Page_61" id="Page_61">[61]</a></p>
+
+<div class="figlarge"><a name="Fig039" id="Fig039"></a>
+<img src="images/illo082.png" alt="Fig. 39" width="600" height="328" />
+<p class="caption just">Fig. 39.&mdash;Skeleton of the Ox: Left Lateral Surface.</p>
+
+<p class="subcaption just">1, Cranium; 2, face; 3, atlas; 4, axis; 5, seventh cervical vertebra;
+6, first dorsal vertebra; 7, thirteenth and last dorsal
+vertebra; 8, lumbar vertebr&aelig;; 9, sacrum; 10, coccygeal vertebr&aelig;; 11, sternum; 12, xiphoid appendix; 13, eighth and
+last sternal rib; 14, costal cartilages; 15, spine of scapula; 16, cartilage of prolongation of the scapula; 17, great tuberosity
+of the humerus; 18, musculo-spiral groove; 19, olecranon process; 20, radius; 21, carpus; 22, pisiform; 23, metacarpus;
+24, rudimentary metacarpal; 25, sesamoid bones; 26, first phalanges; 27, second phalanges; 28, third phalanges; 29, anterior
+iliac spine; 30, pubis; 31, tuberosity of the ischium; 32, great trochanter; 33, supracondyloid fossa of the femur; 34,
+patella, or knee-cap; 35, anterior tuberosity of the tibia; 36, fibula; 37, coronoid tarsal bone; 38, tarsus; 39, calcaneum; 40,
+metatarsus; 41, rudimentary metatarsus; 42, sesamoid bones; 43, first phalanges; 44, second phalanges; 45, third phalanges.</p></div>
+
+<p><b>Unguligrades (Ungulates): Sheep</b>, <b>Ox</b> (<a href="#Fig039">Fig. 39</a>).&mdash;The
+scapula, which is of elongated form, is very narrow in the
+vicinity of the glenoid cavity. The spine, which becomes
+more and more salient towards its inferior part, terminates
+abruptly in a border, which, forming an acute angle with the
+crest, produces a projection which represents the acromion
+process&mdash;a very rudimentary acromion, for it does not reach
+the level of the glenoid cavity. The supraspinous fossa is
+much smaller than the infraspinous; it hardly equals one-third
+the extent of the latter. The anterior border, thin and
+convex in its superior portion, is concave in the rest of its
+extent; the posterior border is thick and slightly concave;
+the spinal border is surmounted by the cartilage of prolongation.
+In the ox the spine of the scapula, in its middle
+portion, is flexed a little backwards on the infraspinous
+fossa.</p>
+
+<p>The great tuberosity of the humerus is highly developed;
+its summit, very prominent, is flexed over the bicipital
+groove; a prominence of the small tuberosity also bends
+over the groove, with the result that at this level the latter
+is converted into a sort of canal. At the inferior extremity
+the condyle, although not large, is recognisable; for it is
+separated from the trochlea by a depression in form of a
+groove. In contrast to the condition found in man, the
+condyle descends to a level a little below that of the internal
+lip of the trochlea. (For the arrangement of the
+epicondyle and the epitrochlea, see <a href="#Page_30">p. 30</a>.) In
+the sheep,<span class="pagenum"><a name="Page_62" id="Page_62">[62]</a></span>
+the deltoid impression is but slightly marked; in the ox,
+it is more evident.</p>
+
+<p>The forearm is directed obliquely downwards and inwards,
+so as to form, with the hand, an angle of which the
+apex is internal; this angular outline of the <i>knee</i> (wrist) is
+so characteristic of ruminants that the corresponding region
+of the horse, when salient inwards, receives the name of
+<i>ox-knee</i>. The radius bears the coronoid process, and the
+larger part of the articular surface which comes in contact
+with the inferior extremity of the humerus; the condyle
+and the trochlea articulate with the radius in front; while
+behind, the trochlea articulates with that part of the sigmoid
+cavity which belongs to the ulna. The posterior
+surface of the shaft of the radius is flattened; its anterior
+surface is slightly convex. The inferior extremity articulates
+with the carpus by a surface which is directed obliquely
+downwards and inwards. The shaft of the ulna is very
+slender, and fused in its middle third with the body of the
+radius; it terminates below, at the level of the external
+part of the inferior extremity of the radius, by a slightly
+expanded portion which, fused with this latter, forms the
+articular surface for the carpal bones.</p>
+
+<p>In the ox the forearm is short; in the sheep it is proportionally
+longer.</p>
+
+<p>The bones of the carpus are six in number&mdash;four in the
+upper row, and two in the lower; they form an irregular
+cuboid mass which contributes to the formation of the
+region known as <i>the knee</i> in ruminants, as in the horse; we
+have already remarked that the name &#8216;wrist&#8217; would be
+more accurate. The anterior surface in its foremost part
+is vertical, and is slightly convex from side to side. At its
+posterior and external part the pisiform bone forms a prominence.</p>
+
+<p>The metacarpus consists of two bones only&mdash;one, well
+developed, which is known as the principal metacarpal, or
+the <i>canon</i> bone (this is the name given to the region in the
+hoofed animals); and a rudimentary one, which is situated
+at the superior and external aspect of the preceding metacarpal.
+Sometimes there is found a third metacarpal<span class="pagenum"><a name="Page_63" id="Page_63">[63]</a></span>
+at the internal aspect; but, when present, it is but very
+slightly developed.</p>
+
+<p>The principal metacarpal consists of two metacarpals
+fused together; on this account the bone is longitudinally
+marked in the median line by a slight depression which
+marks the junction of the two bones of which it is
+formed. In some ruminants (certain species of chevrotains)
+the coalescence does not take place, and the two metacarpals
+remain separate.</p>
+
+<p>The anterior surface of the principal metacarpal is convex
+transversely; its posterior surface is flattened. The superior
+extremity of this bone articulates by two facets with the
+two bones of the inferior row of the carpus; on the internal
+part of the anterior surface of this extremity is found a
+tubercle. The inferior extremity is divided into two parts
+by a fissure or notch; each part is articular, and consists
+of two separate condyles, which are separated from each
+other by an antero-posterior crest; on each side of this
+crest, and behind, are found two sesamoid bones. As for
+the external rudimentary metacarpal bone, it is nothing
+more than a small, short tongue of bone; which, in goats
+and sheep, is often absent.</p>
+
+<p>The division of the inferior extremity of the principal
+metacarpal into two parts is correlated with the two perfect
+digits which give the foot of the ruminant its forked appearance.
+Each digit consists of three phalanges, which are
+directed obliquely downwards and forwards; further, these
+phalanges are inclined a little outwards from the axis of
+the limb, so that the two digits diverge from each other as
+they descend.</p>
+
+<p>The first phalanx, which is the longest, articulates
+superiorly with the principal metacarpal; its inferior
+extremity terminates in a trochlea, and the lip of this,
+which is situated towards the axis of the limb, descends
+lower than that of the opposite side; this arrangement is
+correlated with the divergent direction of the digits. The
+second phalanx has its superior extremity moulded on the
+trochlea which terminates the extremity of the first; its
+inferior extremity is articular, and elongated from before<span class="pagenum"><a name="Page_64" id="Page_64">[64]</a></span>
+backwards. On the posterior surface of this extremity is
+found a sesamoid bone.</p>
+
+<p>With regard to the third phalanx, it presents the form
+of a triangular pyramid, and displays a postero-superior
+concave surface with which the second phalanx articulates;
+an anterior, convex surface, which terminates in a point
+on its anterior part; and an internal surface, which is
+flattened. The third phalanx of each digit is contained
+in a hoof (<i>onglon</i>).</p>
+
+<p>There is also found in ruminants two imperfect rudimentary
+digits, which are represented by two small bones
+situated behind the articulation of the metacarpal and the
+digits which we have just been studying. These rudimentary
+digits are each enveloped in a layer of horn; they
+constitute the <i>spurs</i>. The two digits of the ruminants
+represent the third and fourth fingers of the human hand;
+the two lateral digits, greatly atrophied, are the homologues
+of the second and fifth fingers; the thumb is not
+present.</p>
+
+<p>It is the same as regards the metacarpal bones, which form,
+by their union, the principal metacarpal; the external represents
+the fourth metacarpal, and the internal the third. It is
+to the latter that the tubercle, of which we have already
+made mention, belongs; and with the signification of which,
+because it gives attachment to a muscle, we shall concern
+ourselves in the section on myology (see Radial Muscles).</p>
+
+<div class="figlarge"><a name="Fig040" id="Fig040"></a>
+<img src="images/illo086.png" alt="Fig. 40" width="600" height="440" />
+<p class="caption just">Fig. 40.&mdash;Skeleton of the Horse: Left Lateral Surface.</p>
+
+<p class="subcaption just">1, Cranium; 2, face; 3, atlas; 4, axis; 5, seventh cervical
+vertebra; 6, first dorsal vertebra; 7, eighteenth and last dorsal vertebra; 8, lumbar vertebr&aelig;;
+9, sacrum; 10, coccygeal vertebr&aelig;; 11, sternum; 12, xiphoid appendix;
+13, eighteenth and last sternal rib; 14, costal cartilage; 15, scapula; 16, cartilage
+of extension; 17, great tuberosity of the humerus; 18, deltoid crest; 19,
+olecranon process; 20, radius; 21, carpus; 22, pisiform; 23, principal metacarpal;
+24, metacarpal, external rudimentary; 25, large sesamoids; 26, first phalanx;
+27, second phalanx; 28, third phalanx; 29, ilium, showing external iliac
+fossa; 30, pubis; 31, tuberosity of the ischium; 32, great trochanter; 33,
+infratrochanteric crest, or third trochanter; 34, supracondyloid fossa of the
+femur; 35, knee-cap; 36, anterior tuberosity of the tibia; 37, the fibula; 38,
+tarsus astragalus; 39, calcaneum; 40, principal metatarsal; 41, rudimentary
+external metatarsal; 42, large sesamoids; 43, first phalanx; 44, second phalanx; 45, third phalanx.</p>
+<p class="right fsize80"><i>To face p. 64.</i></p></div>
+
+<p><b>Unguligrades: Horse</b> (<a href="#Fig040">Fig. 40</a>).&mdash;The scapula is narrow,
+compared with that of the animals we have just been considering.
+The anterior border is convex in its superior
+portion, and concave in its inferior; the posterior border
+is slightly hollowed out. The supraspinous fossa is less in
+extent than the infraspinous; but the difference is less than
+that between the same foss&aelig; in the ox and the sheep; in
+the ox, as we have already indicated, the proportion is one-third;
+in the horse, one-half. The spine, which disappears
+at the extremities, is rough and thick in its middle third,
+there forming a kind of tuberosity&mdash;<i>tuberosity of the spine</i>.
+Above and in front of the glenoid cavity is found a strong
+process consisting of a rugous base, and a summit which is<span class="pagenum"><a name="Page_65" id="Page_65">[65]</a></span>
+directed inwards. This forms a kind of hook curved
+towards the inside; it represents the coracoid process.
+The scapula is surmounted by the cartilage of prolongation,
+of which the superior border, which is thin and curved,
+is parallel to the superior border of the prominence of the
+withers; the cartilage forms, consequently, the lateral
+surface of this region. The cartilage of prolongation
+undergoes ossification in old horses. The humerus is short;
+the bicipital groove, situated on the anterior surface of the
+superior extremity, separates the greater tuberosity from
+the lesser, and is divided into two parts by a median ridge;
+it is this portion of the humerus which forms the prominence
+known as the <i>point of the shoulder</i>, or <i>point of the arm</i>. The
+deltoid impression well deserves the name of tuberosity
+which has been given to it, for it is very prominent; the
+musculo-spiral groove is very deep.</p>
+
+<p>At the inferior extremity, the trochlea is large; the
+portion corresponding to the condyle of the humerus in
+man is, in proportion to the latter, of small extent. The
+olecranon fossa is deep. The epicondyle and the epitrochlea
+are somewhat different from those of the human bone. In
+the latter, the epitrochlea is salient towards the inner side,
+causing an increased transverse diameter of the inferior
+extremity of the humerus. In the horse&mdash;it is the same in
+ruminants&mdash;this tuberosity projects backwards, folds on itself
+in forming the internal boundary of the olecranon cavity,
+and exceeds in diameter, in the antero-posterior direction,
+the prominence of the epicondyle, which presents a nearly
+similar arrangement. This latter has, however, a part
+which, projecting externally, is situated at the inferior
+part of a crest, that forms the posterior boundary of the
+musculo-spiral groove. The result is that, contrary to the
+condition found in the human being, the epicondyle is more
+prominent transversely than the epitrochlea, but this latter
+is more salient on the posterior aspect. The epitrochlea
+and the epicondyle offer a larger surface for the origin of
+muscles of the forearm than the same prominences in the
+human bone do for the analogous muscles of the same
+region.</p>
+
+<p><span class="pagenum"><a name="Page_66" id="Page_66">[66]</a></span>Some veterinary anatomists have given to the inferior
+and external articular surface of the humerus the name of
+trochlea; and to the internal one, that of condyle. On
+this account they designate the external prominence as the
+epitrochlea, and the internal one as the epicondyle. In
+addition to the fact that this point of view is not legitimate,
+it produces inevitable confusion when comparing the parts
+with those of the human humerus, and this confusion exists,
+not alone in describing the bone, but also in the description
+of the muscular attachments, and in the comparison of the
+muscles of the forearm of quadrupeds with the corresponding
+muscles in the human species.</p>
+
+<p>The radius is placed in front of the ulna; its body,
+slightly convex forwards, has the anterior surface convex
+transversely, and the posterior surface plane in the same
+direction. It is to the external part of this latter that the
+ulna is applied, which is completely fused with the radius.</p>
+
+<p>The superior extremity of the radius is a little larger than
+the inferior. Its superior aspect, concavo-convex, moulded
+on the inferior articular surface of the humerus, presents
+internally two cavities, which receive the lips of the trochlea,
+and, externally, another, smaller, cavity, which receives the
+condyle. The radius articulates with the trochlea and the
+condyle, having appropriated a portion of the ulna, as is
+proved by the presence of the coronoid process, which belongs
+to the former. This superior extremity presents, internally,
+a tuberosity into which the biceps is inserted; this is the
+bicipital tuberosity; and on the other side is another tuberosity,
+which is a little more prominent than the preceding.</p>
+
+<p>The inferior extremity, which is flattened from before
+backwards, is furrowed on its anterior surface by grooves for
+the passage of muscles (the names of the muscles whose
+tendons pass in these grooves have already been given on
+<a href="#Page_43">p. 43</a>). It articulates at the lower end with the superior
+row of the carpus, and it terminates laterally in tuberosities:
+one, external, on which is found a groove for the tendon of
+the lateral extensor of the phalanges, the homologue of the
+special extensor of the little finger; the other, internal, is a
+little more prominent than the one we have just described.<span class="pagenum"><a name="Page_67" id="Page_67">[67]</a></span>
+These tuberosities are visible under the skin which covers
+the superior and lateral parts of the region known as the
+<i>knee</i>; but which, we again repeat, is no other than the
+wrist.</p>
+
+<p>The ulna has a triangular shaft, situated at the posterior
+surface of the radius, with which it is fused. It disappears
+completely at the level of the inferior third of the forearm.
+Occasionally, in some horses, the ulna is abnormally long,
+in the form of a slender tongue of bone; and extends to the
+neighbourhood of the external tuberosity of the inferior
+extremity of the radius (see <a href="#Fig079">Fig. 79</a>, p. 196). Its superior
+extremity is chiefly represented by the olecranon process,
+which is voluminous in bulk, and forms the projection known
+as the point of the elbow. This process is flattened laterally;
+its internal surface is excavated; the anterior surface, which
+is concave, forms a part of the great sigmoid cavity; the
+remainder of the cavity is formed by the radius.</p>
+
+<p>In the ass, the ulna is a little longer than in the horse&mdash;that
+is to say, it descends lower; and the radius is a little
+more convex anteriorly.</p>
+
+<p>The carpal bones are seven in number&mdash;four in the superior
+row, and three in the inferior. The trapezium is wanting in
+the latter. Sometimes, however, in certain varieties of horses
+the trapezium is developed, but then it is no more than a very
+small osseous nodule. The pisiform bone, situated at the
+external part of the first row of bone, is prominent posteriorly.
+It is of rounder form and flattened from without
+inwards. It articulates with the trapezium and the radius.
+It presents, on its external surface, a groove for the passage of
+the tendon of the posterior ulnar muscle, which is named by
+veterinary anatomists the <i>external flexor of the metacarpus</i>.</p>
+
+<p>The carpus, as a whole, is of an irregularly cuboid shape;
+its anterior surface, slightly convex from side to side, forms
+the skeleton of the region of the <i>knee</i> (wrist). The metacarpus
+is formed of three bones: the principal metacarpal
+and the two rudimentary ones.</p>
+
+<p>The principal metacarpal, which forms the region of the
+<i>canon</i>, is directed vertically; its anterior surface is slightly
+convex transversely. This surface is covered by a number<span class="pagenum"><a name="Page_68" id="Page_68">[68]</a></span>
+of tendons, which slightly alter its appearance; so that it is
+the principal base of this part of the fore-limb. Its posterior
+surface is flattened. The superior extremity of this metacarpal
+presents plane surfaces, variously inclined, with which the
+bones of the inferior row of the carpus articulate. On the
+anterior surface, and a little to the inner side, is found a
+tuberosity, which is destined for the insertion of <i>the anterior
+extensor of the metacarpus</i>, the homologue of the radial
+muscles. The inferior extremity is formed by two condyles,
+an internal and an external; between which is found a
+median crest.</p>
+
+<p>This extremity, the superior extremity of the first phalanx,
+which articulates with it, together with two sesamoid bones&mdash;the
+great sesamoids&mdash;which are situated on its posterior
+surface, collectively form the region which from its rounded
+outlines is called the <i>ball</i>.</p>
+
+<p>With regard to the rudimentary metacarpals, external
+and internal, to which some authors give the name of <i>fibul&aelig;</i>,
+they are applied to the sides of the posterior surface of the
+principal metacarpal. They are elongated bones, of which
+the superior extremity, which is a little thickened, is called
+the <i>head</i>; the lateral bones of the second row of the
+carpus partly rest on the heads of these. They become
+more slender as they descend, and terminate opposite
+the inferior fourth of the principal metacarpal. Each ends
+in a slight swelling, to which the name <i>button</i> has been
+given. The internal one is the better developed.</p>
+
+<p>The rudimentary metacarpals are vestiges of atrophied
+digits, as will be explained <a href="#RudimMetaCarp">further on</a>.</p>
+
+<p>The single finger of the horse consists of three phalanges.
+The first phalanx, which is directed obliquely downwards
+and forwards, corresponds to the constricted region situated
+below the &#8216;ball,&#8217; and known as the <i>pastern</i>. It is flattened
+from before backwards; its anterior surface is convex transversely,
+while the posterior surface is plane. Its superior
+extremity is moulded on the inferior extremity of the
+principal metacarpal, and its inferior extremity, which is
+smaller, presents a trochlea with which the second phalanx
+articulates. This is also directed downwards and forwards,<span class="pagenum"><a name="Page_69" id="Page_69">[69]</a></span>
+and is shorter. It corresponds to the region which, situated
+between the pastern and the hoof, is known as the <i>cornet</i>.</p>
+
+<p>The third phalanx, situated entirely within the hoof,
+has the same direction as the first and second. It is
+large and broad, and presents three surfaces separated by
+well-marked angular borders (see <a href="#Fig096">Fig. 96</a>). The anterior
+surface is oblique downwards and forwards; it is convex
+transversely. The inferior surface is slightly hollowed,
+and is in relation with the sole, or plantar surface of the
+hoof.</p>
+
+<p>The superior surface, which is articular, is divided by a
+median ridge into two lateral cavities, which correspond to
+the trochlea on the inferior surface of the lower extremity
+of the second phalanx. The inferior border corresponds
+in shape with the hoof. The superior border presents
+in its median part a projection, <i>the pyramidal eminence</i>,
+which prolongs at this level the anterior surface of the bone.
+Finally, the posterior border, which is concave, is in contact
+with a sesamoid bone, <i>the lesser sesamoid</i>, which increases
+the superior articular surface behind, and is also in contact
+with the second phalanx.</p>
+
+<p><a name="RudimMetaCarp" id="RudimMetaCarp"></a>As we have just seen, the horse possesses but one digit.
+In the ancestors of the animal&mdash;that is, in the prehistoric
+species which are now extinct (<i>orohippus</i>, <i>miohippus</i>, <i>protohippus</i>,
+or <i>hipparion</i>)&mdash;the number of digits was larger; this
+fact conclusively proves that the rudimentary metacarpals of
+the existing horse are vestiges of digits which have disappeared
+through want of use. In the first of those ancestors&mdash;orohippus&mdash;there
+were four digits; all save the first, the
+thumb, being then developed. In the others of the series
+there existed but three digits. It must, however, be noted
+that in those animals it is always the digit which corresponds
+to the middle finger of the pentedactyl hand that is longest.
+In other less ancient species the lateral fingers are reduced
+to the condition of mere splints of bone. It follows from
+what has been said that the digit which persists in the equine
+species should be considered as the third finger, and that the
+rudimentary metacarpals represent lateral digits considerably
+atrophied.</p>
+
+<p><span class="pagenum"><a name="Page_70" id="Page_70">[70]</a></span>This disappearance of the lateral digits cannot excite
+surprise when we consider the functions of the organs.
+Becoming useless, they must undergo gradual atrophy from
+want of use.</p>
+
+<p>There undoubtedly is, in this former existence of supplementary
+digits in the horse, something analogous to what
+we still find in the pig; where the two principal digits are
+accompanied by two shorter ones, which very probably,
+from their infrequent use, are destined to disappear in a
+more or less distant future.</p>
+
+<h5>Proportions of the Arm, the Forearm, and the
+Metacarpus</h5>
+
+<p>As a supplement to the study of the anterior limbs which
+we have just finished, it appears necessary to give some
+indications of the relative proportions of certain of the
+segments which form these limbs in the plantigrades, the
+digitigrades, and the ungulates.</p>
+
+<p>First, we would remark that, in following this order of
+classification, the scapula becomes less and less narrow,
+and assumes a form more and more elongated. In order to
+convince ourselves of this, it will be sufficient to study the
+bone first in man, then in the bear, the cat, dog, ox, and
+finally in the horse.</p>
+
+<p>As to the proportions of length, which are those we
+should chiefly study, we shall commence with the
+comparison of the forearm and arm&mdash;that is to say,
+the radius and the humerus. The radius is found to
+be longer in proportion to the humerus, as the number
+of digits is smaller, and the hand loses more and more the
+functions of an organ of prehension. In man, the radius is
+shorter than the humerus; in the horse, on the contrary, it
+is longer.</p>
+
+<p>To give an idea of this proportion, we shall employ what
+is known as the antibrachial index. This index gives the
+relation which exists between the length of the forearm and
+that of the humerus; the length of this latter, whatever
+may be the actual measurement, is represented by a fixed<span class="pagenum"><a name="Page_71" id="Page_71">[71]</a></span>
+figure, the number 100. A very simple arithmetical operation
+gives the proportion&mdash;</p>
+
+<table class="formula" summary="Formula page 71">
+
+<tr>
+<td class="center bb nowrap">forearm &times; 100</td>
+<td rowspan="2" class="left">, the quotient obtained furnishes the index.</td>
+</tr>
+
+<tr>
+<td class="center">humerus</td>
+</tr>
+
+</table>
+
+<p>The index is less than 100 if the forearm is shorter than
+the bone of the arm. The index is more than 100 if, on the
+contrary, the forearm is longer.</p>
+
+<p>In man, the radius is shorter than the humerus; indeed,
+in adult individuals of the white race the average index is 74.</p>
+
+<p>In the bear, the length of the radius approaches closely
+to that of the humerus; the index is about 90. In the
+skeleton of a bear in the anatomical museum of the &Eacute;cole
+des Beaux-Arts, the humerus is 33 centimetres in length,
+and the radius 30 centimetres.</p>
+
+<p>In the cat, the radius is very little shorter than the
+humerus. In the dog they are equal. The antibrachial
+index of the latter is, accordingly, 100.</p>
+
+<p>In the horse, the radius is longer than the humerus; the
+index is therefore above 100. Thus, in the skeleton of the
+horse which we have in the museum of the &Eacute;cole des Beaux-Arts, the index is 113&mdash;length of humerus, 29 centimetres;
+length of radius, 33 centimetres. In other skeletons which
+we have measured we found: in one, 108&mdash;humerus, 34
+centimetres; radius, 37 centimetres; in another, 116&mdash;humerus,
+25 centimetres; radius, 29 centimetres.</p>
+
+<p>The metacarpal bone undergoes, relatively to the humerus,
+a proportional elongation, analogous to that of the forearm.</p>
+
+<p>In man, the length of the metacarpus is contained about
+5<sup>1</sup>&#8260;<sub>2</sub> times in that of the humerus; in the bear, it is contained
+4 times; in the dog, 2<sup>1</sup>&#8260;<sub>2</sub> times; in the horse, 1<sup>1</sup>&#8260;<sub>3</sub> times only.</p>
+
+<p>It is well known that the proportions vary according to
+race, and that what we have here given are but the general
+indications.</p>
+
+<h5><a name="ArticAnterLimbs" id="ArticAnterLimbs"></a>The Articulations of the Anterior Limbs</h5>
+
+<p>The knowledge of human arthrology which we presume
+the reader to have previously acquired makes it unnecessary
+for us to enter into numerous details regarding the configuration<span class="pagenum"><a name="Page_72" id="Page_72">[72]</a></span>
+of the articular osseous surfaces and the disposition of
+the fibrous bands that retain them in position. Accordingly,
+in the description which follows, and also in that of the articulations
+of the posterior limbs, we shall occupy ourselves but
+very briefly with the details above referred to, so as to devote
+ourselves especially to the indication of the movements&mdash;that
+is to say, of that which, while easily comprehended
+on recollection of former studies, presents the greatest
+interest from the artistic standpoint in these studies in
+comparative anatomy.</p>
+
+<p><b>The Scapulo-Humeral Articulation.</b>&mdash;The head of the
+humerus and the glenoid cavity of the scapula being in
+contact, the two bones are bound together by a rather loose
+articular capsule, which is strengthened by the muscles of
+this region which fulfil the function of active ligaments.</p>
+
+<p>This articulation, so movable in every direction in the
+human species, is not so much so in quadrupeds; the arm in
+the latter, as also the shoulder, being kept in contact with
+the lateral region of the thorax by the numerous muscles
+which surround it.</p>
+
+<p>Of the movements performed by the humerus, flexion and
+extension are the most extensive; those of abduction and
+adduction are much less so.</p>
+
+<p>It is necessary, before proceeding further, to determine
+what the two principal movements which we have just
+mentioned really are, viz., flexion and extension.</p>
+
+<p>We know that in man the displacements of the humerus
+which take place in the antero-posterior direction are known
+as movement or projection forwards, and movement or projection
+backwards, respectively. We do not say that
+the humerus is flexed or extended, because, in reality, on
+account of the position which the skeleton of the shoulder
+occupies, it is not able to flex or place itself on the line of
+prolongation of the scapula with which it articulates.</p>
+
+<p>In quadrupeds it is not so. The humerus and the scapula
+are contained in almost the same vertical plane; and the
+bone of the arm can take, in relation to the latter, the
+positions characteristic of flexion and extension&mdash;that is, of
+approach to the scapula and removal from it.</p>
+
+<p><span class="pagenum"><a name="Page_73" id="Page_73">[73]</a></span>What makes the meanings of these terms a little confusing
+is that, in human anatomy, some authors consider the
+backward movement of the humerus as extension, and the
+forward movement as flexion; in order to be able to
+compare these movements to those that the femur executes
+in relation to the pelvis.</p>
+
+<p>Now, in our opinion, the indication of this correspondence
+is not absolutely necessary; since it ceases to be exact if
+we wished, from the point of view of the direction given to
+other segments of the skeleton, to establish the same relation
+between the elbow and the articulation of the knee.</p>
+
+<p>It is therefore indispensable, when discussing quadrupeds,
+to discontinue these terms, in order the more readily to
+recognise that: in flexion the inferior extremity of the
+humerus is directed backwards; in extension, on the contrary,
+it is directed forwards. In the first case the humerus
+approaches the scapula; in the second, on the contrary, it
+moves away from it.</p>
+
+<p>These movements, which take place during walking, are
+executed in the following manner: When one of the anterior
+limbs is at the end of that stage of progression which is called
+support (see <a href="#Page_289">p. 289</a>, Displacements of the Limbs)&mdash;that is to
+say, during the time that the foot remains in contact with the
+ground, whilst the trunk is moving forward&mdash;the direction of
+this limb becomes more and more oblique downwards and
+backwards. At a certain moment the limb is raised from
+the ground, to be carried forwards, in order to be again
+pressed on the ground, and recommence a new resting stage.
+In these different phases the humerus is flexed. But at
+the moment that the limb, when carried forwards, is about
+to resume its contact with the ground it becomes directed
+obliquely downwards and forwards; then the humerus is in
+the position of extension.</p>
+
+<p>During these movements of the humerus, there exists an
+essential factor&mdash;that is, the scapular balance. (It is the
+same as what occurs in man when he balances his arm in
+the antero-posterior plane.) When the humerus is flexed,
+the scapula moves in such a way that the superior portion
+projects forwards; when it is extended, the scapula, on the<span class="pagenum"><a name="Page_74" id="Page_74">[74]</a></span>
+other hand, is inclined more backwards. But it is necessary
+to add that, during these displacements, the scapulo-humeral
+angle varies; it tends to close during the flexion
+of the humerus, and becomes more open during extension.</p>
+
+<div class="figmed"><a name="Fig041" id="Fig041"></a>
+<img src="images/illo097a.png" alt="Fig. 41" width="200" height="370" />
+<p class="caption just">Fig. 41.&mdash;Flexion of the
+Humerus: Right Anterior
+Limb of the Horse, External
+Surface (after a Chromophotographic
+Study by Professor
+Marey).</p></div>
+
+<p>The movements and the relations of the humerus and
+the scapula are clearly represented in <a href="#Fig041">Figs. 41</a> and <a href="#Fig042">42</a>,
+reproduced from the chromophotographic studies of Professor
+Marey&mdash;studies relative to the analyses of the movements
+of the horse.<a name="FNanchor_13_13" id="FNanchor_13_13"></a><a href="#Footnote_13_13"
+class="fnanchor">[13]</a> They show clearly the movements of flexion
+and extension of the humerus, also the balancing of the
+scapula which accompanies the movements.</p>
+
+<div class="footnote"><p><a name="Footnote_13_13" id="Footnote_13_13"></a><a href="#FNanchor_13_13"><span class="label">[13]</span></a>
+E. J. Marey, &#8216;Analyses of the Movements of the Horse by the Chromophotograph&#8217;
+(<i>La Nature</i>, June 11, 1898).</p></div>
+
+<div class="figmed"><a name="Fig042" id="Fig042"></a>
+<img src="images/illo097b.png" alt="Fig. 42" width="125" height="377" />
+<p class="caption just">Fig. 42.&mdash;Extension of the
+Humerus: Right Anterior
+Limb of the Horse, External
+Surface (after a Chromophotographic
+Study by Professor
+Marey).</p></div>
+
+<p><b>The Articulation of the Elbow, or the Humero-ulnar
+Articulation.</b>&mdash;In this articulation, which is constructed in
+the form of a true hinge, the movements of flexion and extension
+alone are possible. In flexion, the forearm, directed
+forwards, is folded on the arm, with which, in certain circumstances,
+it comes in contact. For example, in a horse of<span class="pagenum"><a name="Page_75" id="Page_75">[75]</a></span>
+mettle which leaps over an elevated obstacle, the animal
+forcibly raises his fore-limbs by flexing them. Flexion is
+produced to the same extent, and even more so, and for a
+longer period, in felides which crouch.</p>
+
+<p>In extension, on the contrary, the forearm is carried backward.
+This movement being limited only by the contact of
+the tip of the olecranon with the bottom of the olecranon
+fossa of the humerus, the forearm is enabled, in this case, to
+move until it is in line with the arm. For example, during
+walking, when one of the anterior limbs, having reached the
+end of its resting stage, is considerably inclined downwards
+and backwards.</p>
+
+<p>The apex of the olecranon process&mdash;that is to say, the point
+of the elbow&mdash;forms a marked prominence, more salient in
+flexion than in extension, as in the corresponding region of
+the human elbow.</p>
+
+<p><b>The Radio-ulnar Articulation.</b>&mdash;It is in the dog and
+the cat, in which the two bones of the forearm articulate by
+their extremities only, and remain separate in the rest of
+their extent, that the articulations call for special notice.</p>
+
+<p>In the upper part, the radius rotates on itself; while
+below, it rotates around the ulna. It follows that the forearm,
+which in all quadrupeds is in a state of permanent
+pronation, can, in carnivora, take the position of supination,
+or rather, of demi-supination. In fact, whatever be the
+mobility of the two bones of the forearm, the movement is
+not able to bring the palmar surface to the front, but only to
+direct it towards the median line.</p>
+
+<p><b>The Articulation of the Wrist.</b>&mdash;Here are found, as in
+man, three superimposed articulations: the radio-carpal,
+intercarpal, and carpo-metacarpal.</p>
+
+<p>If we remember the movements which take place at the
+plane of these articulations in man, and take account of the
+fact that the mobility of the limbs is reduced just in proportion
+as they are simplified in structure so as to become organs of
+support only, we can easily comprehend that, in the horse and
+the ox, and, in a word, animals that have a canon bone, the
+movements of the wrist are little varied in character, while
+in carnivor&aelig;, on the other hand, they are relatively more so.</p>
+
+<p><span class="pagenum"><a name="Page_76" id="Page_76">[76]</a></span>We will remember that in the ox and the horse the region
+of the wrist is called the <i>knee</i>.</p>
+
+<p>In flexion, the hand is bent backwards; in extension it
+is carried forwards. These two movements take place
+especially in the radiocarpal and intercarpal articulations.
+In the first of these articulations, it is the superior row of
+the carpus which glides backwards and forwards on the
+corresponding articular surface of the forearm. In the
+second articulation, it is the second row which moves;
+gliding on the inferior articular surfaces of the row above
+it. This inferior row carries the metacarpus with it; for
+the carpo-metacarpal articulation is much less mobile than
+either of the other two.</p>
+
+<p>In flexion, the articular surfaces are separated from one
+another in front; and the changes of form which result
+from this are noticeable on the anterior surface of the
+&#8216;knee.&#8217; Moreover, at that moment this region contrasts
+markedly in its outlines with the parts above it and below
+it&mdash;that is to say, with the corresponding surfaces of the
+forearm and of the canon bone.</p>
+
+<p>As for the lateral movements, by which the hand is
+inclined outwards and inwards in its movements at the
+wrist, they exist to an appreciable extent in the cat and the
+dog only; in order to understand this, it is enough to compare
+the shape of the articular surfaces of this region in
+carnivora and the horse, for example. In the latter, those
+surfaces are almost plane; in the cat, on the contrary, they
+are curved (inferior surface of the forearm, concave; superior
+border of the carpus, convex). These latter, then, are, in
+form, similar to those which exist at the same level in the
+human being; this explains the possibility of analogous
+movements of the whole hand&mdash;that is to say, of the movements
+of abduction and adduction.</p>
+
+<p><b>The Metacarpo-phalangeal Articulations.</b>&mdash;With regard
+to the mobility, it is in these articulations, as in those of the
+wrist&mdash;that is to say, although in all quadrupeds the first
+phalanges can be flexed and extended on the metacarpus,
+it is only in the cat and dog that lateral movement is possible.
+Indeed, in the horse, in which the principal metacarpal terminates<span class="pagenum"><a name="Page_77" id="Page_77">[77]</a></span>
+inferiorly in two convex surfaces, which are separated
+by a crest; and where the whole articulates with a
+cavity on the superior extremity of the first phalanx;
+because of the hinging of these surfaces, there can only
+be movements of opening and closing of this articulation.
+The first phalanx is directed backwards during flexion
+and forwards during extension. In the dog and the cat the
+digits can be separated from each other, and also drawn
+together&mdash;that is to say, abducted and adducted; but, as
+in man, these movements can be made only when the first
+phalanges are in the state of extension. During flexion
+they are impossible, because of the tension of the lateral
+ligaments, which increases as the flexion is more pronounced.
+This can be demonstrated, for example, in the cat, which,
+in order to separate the digits, opens the hand widely&mdash;that
+is to say, forcibly raises the first phalanges.</p>
+
+<p><b>The Interphalangeal Articulations.</b>&mdash;The phalanges
+are in contact with one another by surfaces, which,
+on one side, are of trochlear form, and, on the other, are
+moulded on these trochle&aelig;; accordingly, at the level of
+these articulations, the movements of flexion and extension
+only can take place.</p>
+
+<p>In the felid&aelig;, the claws which the third phalanges bear
+cannot be utilized when the latter are in a state of extension,
+at which time, being forcibly raised, they are, in fact,
+placed on the outer sides of the phalanges, which are
+grooved to receive them. But when the animal wishes
+to use them, it flexes those third phalanges, of which
+the terminal extremity is then projected forward, and
+the claws are ready to fulfil their function. But at
+the same time it extends the first phalanges, to produce
+a certain tension of the flexors of the digits, and thus
+enable the latter to act with greater efficacy, with a
+minimum of contraction. We can demonstrate this action
+experimentally on ourselves. It is enough to carry the
+first phalanges forcibly into a state of extension; the
+third phalanges then become flexed, quite spontaneously,
+by the tension of the tendons of the flexors which are
+inserted into them.</p>
+
+<p><span class="pagenum"><a name="Page_78" id="Page_78">[78]</a></span>At the same time, if we examine the felid&aelig; which we have
+taken as examples, when the first phalanges are in the state
+of extension, the digits will be found to be separable, as we
+have already indicated in connection with the metacarpo-phalangeal
+articulations, with the result that the claws are
+then able to lacerate a wider surface.</p>
+
+<p>The extension of the ungual phalanx, which determines
+the retraction of the claw and stops its action, is the
+mechanical result of an elastic, fibrous apparatus which is
+attached to each of the third phalanges, and has its origin
+of the second.</p>
+
+<h4>THE POSTERIOR LIMBS<a name="FNanchor_14_14" id="FNanchor_14_14"></a><a href="#Footnote_14_14" class="fnanchor"
+style="font-weight: normal;">[14]</a></h4>
+
+<p>The posterior limbs are divided, as are the inferior limbs
+of the human being, of which they are the homologues, into
+four parts: pelvis, thigh, leg, and foot.</p>
+
+<div class="footnote"><p><a name="Footnote_14_14" id="Footnote_14_14"></a><a href="#FNanchor_14_14"><span class="label">[14]</span></a>
+Examine <a href="#Fig021">Figs. 21</a>, <a href="#Fig033">33</a>, <a href="#Fig034">34</a>, <a href="#Fig038">38</a>,
+<a href="#Fig039">39</a>, <a href="#Fig049">49</a>.</p></div>
+
+<h5>The Pelvis</h5>
+
+<p>The pelvis, which incompletely limits the abdominal
+cavity, inferiorly in the vertical position of the body and
+posteriorly in the normal attitude of quadrupeds, is formed
+by the iliac bones and sacrum&mdash;the coccyx forming a prolongation
+of the latter. We have already described the two
+latter (<a href="#Page_10">pp. 10</a> and <a href="#Page_11">11</a>) in connection with the vertebral
+column, of which they form the inferior or posterior portion
+or segment, according to the attitude of the individual.</p>
+
+<p><b>The Iliac Bone.</b>&mdash;The iliac or coxal bone, is a paired or non-symmetrical
+bone, united below to its fellow of the opposite
+side, while it is separated from it above by the sacrum.</p>
+
+<p>In all animals, as well as in man, the iliac bone, at the
+beginning of life, consists of three parts, which afterwards
+unite and fuse together and join at the middle of the bottom
+of a deep cavity which is situated on the outer aspect of the
+bone&mdash;the cotyloid cavity.</p>
+
+<p>Of those three portions when examined in the human iliac
+bone, that above the cavity is the ilium; that on the inside
+is the pubis; and the last, the lower one, is the ischium. In<span class="pagenum"><a name="Page_79" id="Page_79">[79]</a></span>
+quadrupeds, the iliac bone being, in its entirety, directed
+much more obliquely downwards and backwards, the relative
+position of these constituent parts is a little modified: the
+ilium is in front, the pubis is still internal, but in a more
+inferior position, and the ischium is behind the cotyloid
+cavity. We notice this peculiarity of the development of
+the iliac bone because it is customary to continue to apply to
+the osseous regions which correspond to these parts the
+names by which they were known when independent bones.</p>
+
+<div class="figmed"><a name="Fig043" id="Fig043"></a>
+<img src="images/illo102a.png" alt="Fig. 43" width="250" height="309" />
+<p class="caption just">Fig. 43.&mdash;The Left Iliac
+Bone of the Human
+Being: External Surface,
+placed in the Position
+which it would
+occupy in the Skeleton
+Of a Quadruped.</p>
+
+<p class="subcaption just">1, Cotyloid cavity; 2, ilium;
+3, iliac crest; 4, anterior iliac
+crest; 5, posterior iliac spine;
+6, pubis; 7, tuberosity of the
+ischium; 8, obturator foramen;
+9, ischiadic spine.</p></div>
+
+<p>The bones which form the skeleton of the pelvis of quadrupeds
+are proportionally more elongated and less massive
+than those of the human pelvis (<a href="#Fig043">Figs. 43</a> and <a href="#Fig044">44</a>).</p>
+
+<div class="figmed"><a name="Fig044" id="Fig044"></a>
+<img src="images/illo102b.png" alt="Fig. 44" width="300" height="289" />
+<p class="caption just">Fig. 44.&mdash;Left Iliac Bone of A
+Quadruped (Horse): External
+Surface.</p>
+
+<p class="subcaption just">1, Cotyloid cavity; 2, ilium, external
+iliac fossa (directed upward in the horse);
+3, iliac crest; 4, anterior iliac spine
+(directed inwards in the horse, it is the
+angle of the haunch); 5, posterior iliac
+spine (directed inwards in the horse; it
+is the angle of the haunch); 6, pubis;
+7, tuberosity of the ischium; 8, obturator
+foramen; 9, ischiadic spine, or
+subcotyloid foramen.</p></div>
+
+<p>We find, on the external surface of the iliac bone, the
+cotyloid cavity, whose border is interrupted by the cotyloid
+notch; a deep notch which looks downwards.</p>
+
+<p><span class="pagenum"><a name="Page_80" id="Page_80">[80]</a></span>In front of this cavity is the ilium. This portion, narrow
+in the part which is next the cavity, is directed forwards and
+upwards, expanding more and more as it passes upwards.
+It presents an external or superior surface (external in some
+animals, superior in others), which recalls the external
+iliac fossa; and an internal or inferior surface, at the superior
+part of which is found the auricular surface for articulation
+with the sacrum.</p>
+
+<p>The anterior border of the ilium is rough; this is the iliac
+crest, at the extremities of which we find, below or outside,
+a prominence which corresponds to the anterior superior
+iliac spine of man; and internally another projection which
+corresponds to the posterior iliac spine.</p>
+
+<p>Immediately above the cotyloid cavity is a rough crest,
+which is known as the <i>supracotyloid crest</i>, which is, however,
+no other than the homologue of the sciatic spine. In
+front of this prominence, the border of the ilium, which is
+notched, forms the great sciatic notch.</p>
+
+<p>If, still taking the cotyloid cavity as the point of
+departure, we proceed inwards&mdash;that is, towards the median
+line of the body&mdash;we find the pubis; if in a posterior
+direction, the ischium. These two portions, pubis and
+ischium, limit an oval orifice, the subpubic foramen.</p>
+
+<p>In the human skeleton, the pubis of one side is united
+to that of the opposite side, to form the pubic symphysis.
+In the animals which we are now studying a portion of the
+ischium enters into the formation of the symphysis; in
+other words, it is formed, not only by the body of the pubis,
+but also by the descending branch or ramus of the pubis
+and a portion of the ascending branch or ramus of the
+ischium, which are fused with those of the opposite side. It
+results that, though in the human being the symphysis
+is short and the ischio-pubic arch large, in quadrupeds it
+is the opposite. In them the arch is a mere slot, and being
+formed by the ischium alone, merits the name of the
+ischial arch. The ischio-pubic symphysis is very large, and
+forms a horizontal surface relatively extensive, a sort of
+floor, on which rest certain organs which occupy the
+cavity of the pelvis.</p>
+
+<div class="figmed"><a name="Fig045" id="Fig045"></a>
+<img src="images/illo104.png" alt="Fig. 45" width="250" height="323" />
+<p class="caption just">Fig. 45.&mdash;Pubic Region of the Pelvis of a Marsupial (Phalanger,
+Fox).</p>
+
+<p class="subcaption just">1, Symphysis pubis; 2, obturator foramen; 3, marsupial bones.</p></div>
+
+<p><span class="pagenum"><a name="Page_81" id="Page_81">[81]</a></span>The posterior and external angle of the ischium is rough
+and prominent; it is the tuberosity of the ischium. This
+forms a projection under the skin; it also does in man when
+the trunk is strongly inclined forwards, while the thighs are
+maintained in the vertical position. In marsupials&mdash;opossum,
+kangaroo, and phalanger&mdash;the pelvis at its pubic
+region is surmounted by two bones, situated one on each side
+of the median line, and arranged in the form of a fork of two
+prongs (<a href="#Fig045">Fig. 45</a>). These, which are called <i>marsupial bones</i>,
+support the pouch which, in animals of this genus, lodges
+their young, which, at the time of birth, are incapable of
+supporting a separate existence, their development being
+absolutely incomplete.</p>
+
+<p>In the cetaceans&mdash;for example, the dolphin&mdash;because of
+the absence of posterior limbs, the pelvis is represented
+by two separate bones only, which have no connection with
+the vertebral column. In birds, the pelvis is remarkable
+for its elongated form (see for its form <a href="#Fig021">Fig. 21</a>, and for
+details <a href="#Fig046">Fig. 46</a>). The cotyloid cavity is pierced by an
+opening, and presents on its posterior border, which is<span class="pagenum"><a name="Page_82" id="Page_82">[82]</a></span>
+here a little prominent, a surface with which the great
+trochanter is in contact.</p>
+
+<p>The ilium is very highly developed, and is fused in the
+median line with the ilium of the opposite side, the last dorsal
+vertebr&aelig;, the lumbar vertebr&aelig;, and the sacrum. Because
+of these relations with the dorsal vertebr&aelig;, it is in contact
+anteriorly with the last ribs, which consequently emerge
+from each side of the iliac region of the pelvis.</p>
+
+<p>The ischium forms a plate of bone which, in part, closes
+the external portion of the cavity of the pelvis. Its superior
+border is separate for a certain distance from the external
+border of the ilium; there is thus left an opening of more
+or less considerable size, which represents or takes the place
+of the great sciatic notch.</p>
+
+<div class="figmed"><a name="Fig046" id="Fig046"></a>
+<img src="images/illo105.png" alt="Fig. 46" width="400" height="321" />
+<p class="caption just">Fig. 46.&mdash;Pelvis of a Bird (the Cock): External Surface, Left Side.</p>
+
+<p class="subcaption just">1, Ilium; 2, ischium; 3, pubis; 4, inferior extremity of the pubis;
+5, sciatic foramen; 6, oval foramen, homologous to the obturator; 7,
+coccygeal vertebr&aelig;.</p></div>
+
+<p>The pubis, long and slender, is in connection with the
+inferior border of the ischium, of which it follows the general
+direction; and circumscribes with this latter, below the
+cotyloid cavity, an oval orifice, which is the homologue of
+the obturator foramen. Its inferior extremity reaches
+beyond the corresponding part of the ischium, bending<span class="pagenum"><a name="Page_83" id="Page_83">[83]</a></span>
+towards the middle line, but without joining the pubis of
+the opposite side. On this account there is no symphysis
+pubis in birds. Nevertheless, an exception must be noted
+in the case of the ostrich, the pubic bones of which meet in
+the middle line, and are articulated in form of a symphysis.</p>
+
+<h5>The Thigh</h5>
+
+<p>A single bone, the femur, forms the skeleton of this
+portion of the lower limb.</p>
+
+<p><b>The Femur.</b>&mdash;The bone of the thigh is, in man, directed
+downwards and inwards; this obliquity, we may remind
+the reader, is due to the difference in length of the two
+condyles which form its inferior extremity; the internal
+is the more prominent, the result of which is that when
+the femur is held vertically, the internal condyle descends
+lower than the external. Now, as those two articular
+expansions rest on the horizontal plane formed by the upper
+extremity of the tibia, it follows that the superior part of
+the femur inclines towards the side of the shorter condyle&mdash;that
+is to say, outwards&mdash;and that, the leg being
+vertical, it and the bone of the thigh unite in forming an
+angle, of which the apex is directed towards the inner side
+of the knee.</p>
+
+<p>In many mammals the two condyles are equally prominent,
+the result of which is that the femur inclines neither
+inwards nor outwards, but is contained in a plane parallel
+to the axis of the trunk; while the leg is included in the
+same plane. Nevertheless, although contained in the
+plane which we have just indicated, the femur is obliquely
+placed, and directed downwards and forwards; it accordingly
+forms, with the pelvis, an angle, of which the opening
+is directed to the anterior aspect of the body.</p>
+
+<p>In reptiles and in birds the femur and leg are both placed
+in the same plane, but this plane is not parallel to the
+axis of the trunk. This is the result, on the one hand, of
+the thorax being wide, and, on the other hand, of the femur,
+which is directed forwards, being in contact by its anterior
+extremity with the lateral aspect of the costal region, it is<span class="pagenum"><a name="Page_84" id="Page_84">[84]</a></span>
+thus necessarily placed in a direction forwards and outwards,
+and the knee is further removed from the axis of the trunk
+than is the articulation which unites the thigh with the
+pelvis.</p>
+
+<p>The femur, like the humerus, is almost completely enveloped
+by muscular masses, which bind it to the lateral
+walls of the abdomen. Its inferior extremity alone is free,
+and is always the more so in proportion to its elongation&mdash;that
+is to say, as it belongs to an animal whose foot is more
+divided. The femur in this respect conforms to the law
+which we have indicated in connection with the bone of the
+arm, in which the development, as to length, is in proportion
+to the division of the hand.</p>
+
+<p>If we compare the femur of certain animals with that
+of man, we see that the corresponding details of form
+are readily recognisable, but they are slightly modified.
+Thus, on examining the superior extremity, we find there
+a head, a neck, a great trochanter, and a lesser; but the
+neck is usually short and thick, and the great trochanter
+does not occupy the same level with regard to the articular
+head of the bone. In man, the great trochanter does not
+rise to the level of the head of the femur; in the dog and
+the cat it approaches that level; in the horse and in
+ruminants it rises above it.</p>
+
+<p>With regard to the inferior extremity, its surfaces
+undergo modifications which are further accentuated as
+we pass from the digitigrades to the ungulates, or unguligrades.
+We know that in man the femoral trochlea
+is continuous behind, without interruption, with the condyles&mdash;that
+is to say, that each of the condyles is the continuation
+of one of the lips of the trochlea. We have just
+said that the trochlea is continuous without interruption
+with the condyles; this is accurate. Nevertheless, we
+must remark that, at the level of the junction of these
+surfaces, the bone presents a slight constriction, which is
+more marked on the external than on the internal aspect.
+This constriction, which is but slightly marked in man, is
+accentuated in the dog and the cat; in the ruminants and
+the solipeds it is still more pronounced so that we may<span class="pagenum"><a name="Page_85" id="Page_85">[85]</a></span>
+say that in these latter the trochlea and the condyles are
+almost completely separated.</p>
+
+<p>There is another modification in regard to the prominence
+and extent of the two lips of the trochlea. In
+man, the external lip of the trochlea reaches higher than the
+internal, and it is more prominent in front. In the dog,
+these lips are equal with regard to thickness, but the
+external still reaches higher than the internal; in the
+cat, they are equal in every respect; in ruminants and
+solipeds the internal lip is wider, thicker, and rises higher
+than the external.</p>
+
+<p>In animals the trochlea is, as a general rule, narrower
+than in man, and the condyles are more prominent posteriorly;
+so that, when viewed from one of the lateral
+aspects, the inferior extremity of the femur is, in them,
+better developed in the antero-posterior direction.</p>
+
+<p>In birds, the femur is shorter than the bones of the leg;
+its great trochanter is in contact with a prominence which
+occupies the posterior part of the border of the cotyloid
+cavity. Instead of articulating at the level of the knee,
+with the knee-cap and tibia only, as in man, it articulates,
+in addition, with the superior extremity of the fibula. A
+similar arrangement is found in marsupials and reptiles.</p>
+
+<p><b>The Knee-cap.</b>&mdash;This bone, developed in the thickness of
+the tendon of the triceps muscle of the thigh, is in contact,
+by its posterior surface, with the femoral trochlea. The
+two articular surfaces which are applied to the lips of the
+trochlea present, with regard to their extent, an inequality
+which is in proportion to the arrangement which we have
+above indicated&mdash;that is, while in man it is the external
+surface which is the larger, in the horse it is the internal.
+We shall see what the general form of the knee-cap is
+when we come, <a href="#TarsusBones">later on</a>, to study more particularly the
+posterior limbs of some animals.</p>
+
+<h5>The Leg</h5>
+
+<p>The skeleton of the leg consists of two bones: the tibia
+and the fibula. The tibia is the more internal and the<span class="pagenum"><a name="Page_86" id="Page_86">[86]</a></span>
+larger of the two; the fibula is slender, and situated on the
+outer side, and a little posterior to, the preceding. The
+fibula is more or less developed according to the species;
+in some it is complete, in others it is very much atrophied.</p>
+
+<p>This peculiarity may be compared with that which we
+have drawn attention to regarding the development of the
+ulna; but here the seriation is less distinct. Not only in
+the different species, but even in the individuals of the same
+species, the development of the fibula presents little regularity.
+In quadrupeds, the bones of the leg are directed
+obliquely downwards and backwards, so that they form,
+with the femur, which is directed obliquely downwards
+and forwards, an angle, the apex of which is placed at the
+anterior surface of the knee.</p>
+
+<p><b>Tibia.</b>&mdash;The tibia of quadrupeds is readily comparable
+with that of man; as in the case of the latter, its shaft has
+three surfaces&mdash;an external, which is hollowed out in its
+upper portion, and becomes anterior below; an internal,
+slightly convex and subcutaneous; the posterior, which
+presents, in its superior part, a crest, the oblique line of the
+tibia, and some rugosities. The borders separate the
+surfaces. The anterior border, or crest of the tibia, is
+prominent in its superior part; below it gradually disappears
+in passing towards the internal aspect of the
+inferior extremity. The external and internal borders
+separate the corresponding surfaces from the posterior one.</p>
+
+<p>The superior extremity is thick, and expands in forming
+three tuberosities: two lateral and an anterior. The
+anterior tuberosity, situated at the superior part of the
+crest of the tibia, is very prominent; for this reason the
+superior extremity is very much expanded in the antero-posterior
+direction&mdash;hence it results that this diameter is
+equal to the transverse, and sometimes even greater. In
+man, it is the latter which is the larger. The anterior
+tuberosity is visible under the skin.</p>
+
+<p>The inferior extremity, less thick, is prolonged internally
+by a prominence which corresponds to the internal malleolus
+of man. In animals whose fibula is but slightly
+developed the tibia presents, on the external part of its<span class="pagenum"><a name="Page_87" id="Page_87">[87]</a></span>
+inferior extremity, a small prominence, which replaces the
+fibular malleolus. The ruminants must, however, be excepted,
+in which we find in this region a special bone, which
+certain authors look on as the inferior part of the fibula
+(see <a href="#Page_97">p. 97</a>). The inferior surface of this extremity of the
+tibia is articular; and is in contact with one of the tarsal
+bones, the astragalus. Because the superior surface of
+this latter has the form of a pulley, a pulley much more
+marked than that on the human astragalus, the corresponding
+surface of the tibia, which has the opposite form,
+presents two lateral cavities, separated by a median ridge,
+which is directed forwards and slightly outwards; this
+ridge projects into the groove of the pulley.</p>
+
+<p><b>The Fibula.</b>&mdash;This bone, situated at the back of the
+external surface of the tibia, is, as we have said, more or
+less developed. Its superior extremity, or head, articulates
+with the external tuberosity of the tibia. Its inferior
+extremity, when it exists&mdash;it is this which disappears in
+animals which have the fibula incompletely developed&mdash;forms
+a prominence which, placed on the external surface
+of the inferior extremity of the tibia, articulates with the
+astragalus, and recalls the external malleolus of man.</p>
+
+<p>We have stated above that it is the inferior extremity
+of the fibula which disappears when the bone is incompletely
+developed; it is necessary to except the bat, in
+which the fibula, fairly well developed at its inferior
+extremity, by which it articulates with the tibia, thins
+off in its superior portion, and does not reach the corresponding
+extremity of the latter. Further, as in this
+animal the surface of the knee, which corresponds to the
+anterior surface of the same region in other animals, is
+turned backwards, the result is that the fibula is situated
+on the inner side of the tibia, instead of being placed on
+the outer.</p>
+
+<h5>The Foot</h5>
+
+<p>The foot, in animals, as well as in man, is formed of three
+portions, which, as we pass from the part which articulates
+with the leg towards the terminal extremity, are: the tarsus,<span class="pagenum"><a name="Page_88" id="Page_88">[88]</a></span>
+the metatarsus, and the toes. These three portions are the
+homologues of the carpus, the metacarpus, and the fingers,
+which, as we have already seen in the case of the hand, are
+the osseous groups which form its skeleton. The tarsus
+is formed of short bones, as the carpus is; these are, in
+man, seven in number. The bones are arranged in two
+rows: one, the posterior, formed of two bones superimposed&mdash;the
+astragalus, by which the tarsus articulates with the leg,
+and the calcaneum, which forms the prominence of the heel;
+and an anterior row formed of five juxtaposed ones&mdash;the
+cuboid, situated externally, and the scaphoid internally, in
+front of which are found the three cuneiforms. To the
+tarsus succeeds the metatarsus, whose form reminds us very
+much of that of the metacarpals.</p>
+
+<p>With regard to the toes, which we enumerate in proceeding
+from the most internal to the most external, they are formed
+of phalanges, which are three in number for the four outer
+toes; but the number is reduced to two in the case of the
+first&mdash;that is, the so-called great-toe.</p>
+
+<p>The bones of the tarsus are not seven in all animals; they
+are fewer in ruminants and solipeds. We already know
+that, in the latter, the metacarpals and the digits are
+equally reduced in number; the same is the case for the
+metatarsals and the toes. We will analyze these differences
+when dealing with the <a href="#TarsusBones">species individually</a>.</p>
+
+<div class="figmed"><a name="Fig047" id="Fig047"></a>
+<img src="images/illo112.png" alt="Fig. 47" width="500" height="227" />
+<p class="caption just">Fig. 47.&mdash;Posterior Limb of the Horse placed in the Position which
+it should occupy if the Animal were a Plantigrade: Left Limb,
+External Surface.</p>
+
+<p class="subcaption just">1, Tibia; 2, astragalus; 3, calcaneum; 4, metatarsus; 5, first phalanx;
+6, second phalanx; 7, third phalanx.</p></div>
+
+<p>When we studied the anterior limbs, we saw in passing
+from the plantigrades to the digitigrades, and finally the
+ungulates, or unguligrades, as the hand became hyperextended,
+the carpus was raised and more and more removed
+from the ground. We shall establish the existence
+of the same condition in the posterior limbs; in the
+plantigrades the tarsus rests on the ground; in the digitigrades
+it is removed from it; while in the unguligrades the
+distance which separates it from the point of support is
+still more considerable; and it is, indeed, necessary to
+imagine that if these latter were plantigrades, would
+occupy the position on the ground which is indicated by
+<a href="#Fig047">Fig. 47</a>.</p>
+
+<p>In veterinary anatomy the tarsus is called the <i>ham</i>; a<span class="pagenum"><a name="Page_89" id="Page_89">[89]</a></span>
+name we adopt in conformity with usage, but which we
+cannot but regret, as in human anatomy the ham is the
+region of the posterior surface of the knee.</p>
+
+<p>The general arrangement of the region of the digits of the
+posterior limbs in birds, presents some points of interest.</p>
+
+<p>We shall merely say with regard to the metatarsus, that
+it is formed by a single bone, which in the cock is furnished
+towards its inferior third with a pointed process, the <i>spur</i>.
+At the inferior part, there is, however, found another, which
+is but very slightly developed, and with which the first
+phalanx of the innermost toe articulates.</p>
+
+<p>The toes are, in the majority of species, four in number:<a name="FNanchor_15_15"
+id="FNanchor_15_15"></a><a href="#Footnote_15_15" class="fnanchor">[15]</a>
+an internal, which is directed backwards, and corresponds to
+the great-toe; the others are directed forwards. This
+arrangement is constant in grallatores (wading birds), gallinace&aelig;<a name="FNanchor_16_16"
+id="FNanchor_16_16"></a><a href="#Footnote_16_16" class="fnanchor">[16]</a>
+(domestic fowls), and raptores (birds of prey).</p>
+
+<div class="footnote"><p><a name="Footnote_15_15" id="Footnote_15_15"></a><a href="#FNanchor_15_15"><span
+class="label">[15]</span></a> In spite of the fact that the custom is to designate the terminal portions
+of the foot of birds by the name of digits, we prefer to employ here
+the terms <i>foot</i> and <i>toes</i>. In adopting this decision we believe we are
+acting according to a more didactic method. Homology of names should,
+in our opinion, always accompany homology of regions.</p></div>
+
+<div class="footnote"><p><a name="Footnote_16_16" id="Footnote_16_16"></a><a href="#FNanchor_16_16"><span
+class="label">[16]</span></a> With regard to the gallinace&aelig;, we must add that in certain varieties
+the number of toes is five; those which are directed forwards are three
+in number; the internal one which passes backward, is double. The two
+toes which are the subject of this special arrangement are placed very
+close together, and are nearly always superimposed. This condition is
+found in the Houdan and Dorking breeds.</p></div>
+
+<p>In climbing birds (parrots, woodpeckers, and toucans), the<span class="pagenum"><a name="Page_90" id="Page_90">[90]</a></span>
+innermost toe is not only directed backward, but the external
+toe accompanies it in that direction; consequently, there are
+two posterior and two anterior toes. Sometimes they are
+all directed forwards; this disposition is found in the
+martins. In some birds, the number of toes is reduced to
+three: the cassowary shows this reduction; in others, the
+number is still further diminished&mdash;the ostrich, for example,
+has but two.</p>
+
+<div class="figmed"><a name="Fig048" id="Fig048"></a>
+<img src="images/illo113.png" alt="Fig. 48" width="400" height="310" />
+<p class="caption just">Fig. 48.&mdash;Skeleton of the Foot of a Bird (the Cock): Left Side,
+External Surface.</p>
+
+<p class="subcaption">1, Metatarsus; 2, spur; 3, rudimentary metatarsal; 4, first toe;
+5, second toe; 6, third toe; 7, fourth toe.</p></div>
+
+<p>Further, we find that, in general, the number of the
+phalanges increases, when we examine the toes in commencing
+with the most internal (<a href="#Fig048">Fig. 48</a>): this has two;
+then the following one three; that which comes next in
+order has four; and the most external toe has five. The
+phalanges of this last are short; so that, although it is
+formed by a larger number of bones, it is not the longest of
+the toes.</p>
+
+<h4><a name="TarsusBones" id="TarsusBones"></a>THE POSTERIOR LIMBS IN SOME ANIMALS.</h4>
+
+<p><b>Plantigrades: Bear</b> (<a href="#Fig033">Fig. 33</a>, p. 50).&mdash;The external
+iliac fossa is very deep. The femur is longer than the
+bones of the leg; the great trochanter does not reach the<span class="pagenum"><a name="Page_91" id="Page_91">[91]</a></span>
+level of the head of the femur. The fibula is well developed;
+it is united to the tibia at its superior and inferior extremities
+only.</p>
+
+<p>The foot, which, as in the case of the hand, rests on the
+ground by the whole extent of its plantar surface, presents
+five toes; the shortest of these is the internal&mdash;that is, the
+toe which corresponds to the great-toe in man; the third
+and fourth are the longest, and they are almost equal; there
+is a very slight difference in favour of the fourth, which is
+slightly superior in dimensions to the third.</p>
+
+<p><b>Digitigrades: Cat</b>, <b>Dog</b> (<a href="#Fig034">Fig. 34</a>, p. 52).&mdash;The external
+iliac fossa, which looks outwards, is deep; the iliac
+crest is convex anteriorly, the convexity is continued from
+one iliac spine to the other.</p>
+
+<div class="figmed"><a name="Fig049" id="Fig049"></a>
+<img src="images/illo114.png" alt="Fig. 49" width="300" height="359" />
+<p class="caption just">Fig. 49.&mdash;Pelvis of the Dog, seen from Above.</p>
+
+<p class="subcaption just">1, Iliac crest; 2, external iliac fossa; 3, sacrum; AA&#8242;, bi-iliac diameter;
+BB&#8242;, bi-ischial diameter.</p></div>
+
+<p>In the dog, the distance which separates the anterior
+iliac spines is less than that which separates the ischia
+(<a href="#Fig049">Fig. 49</a>). On a skeleton which we measured, the transverse
+diameter, the distance from the anterior iliac spine of one
+side to that of the opposite side, was 8 centimetres, whilst the
+distance which separated the ischia was 105 millimetres;
+on another skeleton, the first measurement was 127 metres,
+and the second was 146 millimetres. It seems to us unnecessary
+to multiply examples.</p>
+
+<div class="figmed"><a name="Fig050" id="Fig050"></a>
+<img src="images/illo115.png" alt="Fig. 50" width="250" height="371" />
+<p class="caption just">Fig. 50.&mdash;Pelvis of a Felide (Lion), viewed from Above.</p>
+
+<p class="subcaption just">1, Iliac crest; 2, external iliac fossa; 3, sacrum; AA&#8242;, bi-iliac diameter;
+BB&#8242;, bi-ischial diameter.</p></div>
+
+<p>In the cat, the iliac spines are but slightly marked; the<span class="pagenum"><a name="Page_92" id="Page_92">[92]</a></span>
+result is that the iliac crest is almost confounded with the
+inferior and superior borders of the ilium. The two diameters
+referred to above are almost equal (<a href="#Fig050">Fig. 50</a>).</p>
+
+<p>We draw particular attention to what we have just
+noted in regard to the transverse proportions of the
+iliac and ischiatic regions of the dog and the cat. These
+relations are evidently of importance with regard to shape,
+since the iliac crests and the ischia are noticeable beneath the
+skin.</p>
+
+<p>In the dog, the shaft of the femur is slightly convex in
+front; but in the cat it is straight. The borders of the shaft
+are slightly marked, so that it is almost cylindrical. The <i>linea
+aspera</i>, less prominent than in man, gains in width what it
+loses in elevation; it constitutes what may almost be called
+a rough <i>surface</i>. This surface is narrower in its middle
+portion than at its extremities, where it bifurcates to go
+upwards to the two trochanters, and downwards to the two
+condyles. At the superior extremity, the neck is short, the
+great trochanter reaching almost to the level of the head of
+the femur; the digital <i>cavity</i>, which is situated on the internal
+surface of the great trochanter, is very deep. At its
+inferior extremity it projects strongly backward. The
+trochlea is narrow; in the cat its two lips are equally prominent,
+while in the dog the external is a little more elevated<span class="pagenum"><a name="Page_93" id="Page_93">[93]</a></span>
+than the internal, which on its part is a little thicker. The
+trochlea is still more independent of the condyles than in the
+human femur; it is separated from these latter by a slight
+constriction.</p>
+
+<p>The knee-cap is long and narrow.</p>
+
+<p>The tibia of the dog is slightly curved from before backward:
+it has the form of an elongated S; this conformation
+is in great part due to the very marked projection of the
+anterior tuberosity and of the superior portion of the crest,
+which, a little below that tuberosity, turns abruptly backwards,
+and thus describes a curve the concavity of which
+is directed forward. The superior part of the external
+surface is very much hollowed out.</p>
+
+<p>The superior extremity is much thicker than the inferior
+one. It is not only wide in the transverse direction, but is
+more especially extended from before backwards; the prominence
+of the anterior tuberosity is the cause of the elongation
+of this antero-posterior diameter. On the posterior part of
+the external tuberosity is found a surface to which the
+superior extremity of the fibula is applied.</p>
+
+<p>The inferior extremity presents an articular surface, which
+is formed of two lateral cavities, separated by a crest, which
+is directed obliquely forwards and outwards. The internal
+part is prominent, and forms the internal malleolus.</p>
+
+<p>With regard to the fibula, it is united to the tibia by its
+extremities and by the inferior half of its shaft. This latter
+is more expanded below than in its upper part. The
+superior extremity is flattened from without inwards. The
+inferior extremity projects beyond the articular surface of the
+tibia, and forms the external malleolus, which, instead of, as
+in man, descending further than the tibial malleolus, stops
+at the same level, and even descends a little less than does
+the latter.</p>
+
+<p>In the cat, the curve of the tibia is less pronounced; this is
+due to the fact that the crest, instead of being concave in its
+middle portion, is slightly convex anteriorly. The fibula, less
+flattened than that of the dog, is united to the tibia by
+its extremities only, and is separate in the rest of its extent.</p>
+
+<p>The bones of the tarsus are seven in number, and arranged<span class="pagenum"><a name="Page_94" id="Page_94">[94]</a></span>
+as in man, with this difference (which is easily comprehended),
+that their general relations are changed on account of the
+vertical direction of the tarsus. For example, the astragalus,
+instead of being above the calcaneum, is situated in front of
+it; the cuneiform bones, instead of being situated in front
+of the scaphoid, are found below it, etc.</p>
+
+<p>These animals have but four well-developed metatarsals;
+that which corresponds to the great-toe is represented merely
+by a small style-shaped bone, situate at the internal part of
+the region.</p>
+
+<p>Nevertheless, we find this toe fully developed in some dogs.
+Notwithstanding this, the bones which form it are, however,
+but rudimentary, and much smaller than those of the innermost
+digit of the fore-limb.</p>
+
+<p>Sometimes it is double; this condition is demonstrable
+in individuals belonging to breeds of large size. The median
+metatarsals are more fully developed than the other bones
+of the same region which are next them. Viewed as a whole,
+the metatarsal bones are a little longer than the metacarpals;
+the result is that the distance which separates the tarsus
+from the ground is a little greater than that which separates
+the carpus from the plane on which the anterior limbs rest.
+The length of the calcaneum still further exaggerates this
+difference, and, as in the animals with which we shall occupy
+ourselves later on, the projection which this bone forms is
+distinctly higher than that which is produced by the pisiform.</p>
+
+<p>The metatarsus, as a whole, is a little narrower than the
+metacarpus; not only on account of the presence of a thumb
+in the anterior limb, but, further, because the bones of this
+latter region are wider than those of the corresponding part
+of the posterior limb.</p>
+
+<p>The phalanges closely resemble those of the anterior
+limbs.</p>
+
+<p><b>Unguligrades: Pig</b> (<a href="#Fig038">Fig. 38</a>, p. 58).&mdash;The pelvis in
+this animal presents a few of the characters which we
+shall again meet with in the ruminants and the solipeds;
+however, the posterior (or internal) iliac spines are relatively
+more widely separated from one another than in the latter.<span class="pagenum"><a name="Page_95" id="Page_95">[95]</a></span>
+This arrangement reminds us of that found in the carnivora.</p>
+
+<p>The femur presents nothing very special. The knee-cap
+is thick, and ovoid in outline.</p>
+
+<p>The fibula is completely developed, as in the carnivora;
+and is connected with the tibia at both its extremities.</p>
+
+<p>The tarsus consists of seven bones. The astragalus and
+the calcaneum differ slightly from those of ruminants.</p>
+
+<p>The foot, like the hand, has two median digits which rest
+on the ground by their third phalanges; and an internal and
+an external digit, which are removed from it. The metatarsals
+are a little longer than the metacarpals.</p>
+
+<div class="figmed"><a name="Fig051" id="Fig051"></a>
+<img src="images/illo118.png" alt="Fig. 51" width="350" height="322" />
+<p class="caption just">Fig. 51.&mdash;Pelvis of the Ox: Superior Surface.</p>
+
+<p class="subcaption just">1, Iliac crest; 2, external iliac fossa; 3, sacrum; AA&#8242;, bi-iliac diameter;
+BB&#8242;, bi-ischiadic diameter.</p></div>
+
+<p><b>Unguligrades: Sheep</b>, <b>Ox</b> (<a href="#Fig039">Fig. 39</a>, p. 61).&mdash;The
+pelvis of ruminants of this group closely resembles that of
+the horse, which we will study later on (see <a href="#Page_99">p. 99</a>). That
+which we must at once point out is that, with regard to
+the ratio formed by a comparison of the bi-iliac and bi-ischiatic
+diameters, it may be placed between the ratio
+obtained in comparing those diameters in the pelvis of the
+carnivora and that of the solipeds. Indeed, in the ruminants,
+the distance which separates the ischia exceeds the
+width of one iliac only, and does not equal, as in the
+felide, the total width of the anterior part of the pelvis<span class="pagenum"><a name="Page_96" id="Page_96">[96]</a></span>
+(<a href="#Fig051">Fig. 51</a>). In the skeleton of the ox, which forms part of the
+anatomical museum of the &Eacute;cole des Beaux-Arts, the bi-ischiadic
+diameter is 39 centimetres, whilst the width of one
+iliac crest is 29 centimetres, so that, in contrast to that which
+we find in the dog, the width of the ischiadic region is less
+than that formed in front by the addition of the iliac crests.</p>
+
+<p>The great trochanter is large, and extends beyond the level
+of the plane in which the head of the femur is found.</p>
+
+<p>In the ox, the linea aspera, instead of being a narrow crest,
+is spread out, and forms in reality a surface; the posterior
+surface of the femur. At the inferior and external part of this
+surface is situated a cavity which surmounts the corresponding
+condyle, and is known as the <i>supracondyloid fossa</i>. On the
+internal part of the same region there are a series of tubercles,
+which, because of their position in relation to the corresponding
+condyle, constitute the <i>supracondyloid crest</i>.</p>
+
+<p>The internal lip of the trochlea is much thicker and much
+more prominent than the external.</p>
+
+<p>The details which we have just now examined in connection
+with the ox are less marked in the sheep.</p>
+
+<p>The trochlea, narrow as a whole, is clearly separate from
+the condyles by a very marked constriction.</p>
+
+<p>The patella, which is thickened in the antero-posterior
+direction, has the shape of a triangular pyramid with the
+base upwards. Its posterior surface, which articulates
+with the trochlea, presents an arrangement which is adapted
+to the disposition of this latter&mdash;that is to say, the surface
+which is in contact with the internal lip is larger
+than that which articulates with the lip of the opposite
+side.</p>
+
+<p>The tibia of the ox is proportionately shorter than that of
+the sheep. The shaft of this bone is flattened from before
+backwards, in its inferior half. The median crest of the
+articular surface of the inferior extremity is the most prominent
+part of that region.</p>
+
+<div class="figmed"><a name="Fig052" id="Fig052"></a>
+<img src="images/illo120.png" alt="Fig. 52" width="250" height="440" />
+<p class="caption just">Fig. 52.&mdash;Tarsus of the Ox: Posterior Left Limb, Antero-external
+Surface.</p>
+
+<p class="subcaption just">1, Tibia; 2, coronoid bone of the tarsus; 3, superior articular surface
+of the astragalus; 4, inferior articular surface of the astragalus; 5,
+calcaneum; 6, cuboido-scaphoid bone; 7, great cuneiform bone&mdash;the
+small cuneiform bone is situated at the back of the latter; 8, principal
+metatarsal&mdash;the small, or rudimentary, metatarsal bone is very small;
+it is situated at the back of the preceding, and is not to be seen in the
+sketch. It would be visible if the view were directly lateral, but then
+the superior and inferior articular surfaces of the astragalus would be less
+apparent.</p></div>
+
+<p>The fibula is extremely atrophied. The shaft and superior
+extremity of this bone are represented merely by a simple
+ligamentous cord, which is sometimes ossified. There remains
+of the fibula, as a portion well and distinctly developed,<span class="pagenum"><a name="Page_97" id="Page_97">[97]</a></span>
+the inferior extremity only. This presents itself under
+the form of a small bone situated in the region ordinarily
+occupied by the inferior extremity of the outer bone of the
+leg&mdash;that is to say, the external part of the inferior extremity
+of the tibia; this little bone articulates with the
+astragalus and the calcaneum. Some authors consider it
+to be a tarsal bone, and describe it under the name of the
+coronoid bone of the tarsus (<a href="#Fig052">Fig. 52</a>, 2). It is not, perhaps,
+quite legitimate to describe it as a bone of this region, for<span class="pagenum"><a name="Page_98" id="Page_98">[98]</a></span>
+it has not a homologue in the tarsus of other animals. Its
+external surface is rough; its superior border is furnished
+with a small pointed process occupying a depression which
+is provided for it by the tibia. It reaches lower down than
+the latter, and forms in this way a sort of external malleolus,
+which frames, on the outer aspect, the mortise in which the
+astragalus is maintained.</p>
+
+<p>The tarsus, as a whole, has an elongated form; it is formed
+of five bones: the astragalus, calcaneum, cuboid and scaphoid,
+which coalesce, to form a single bone, and two cuneiform
+bones, which correspond to the second and third cuneiform
+bones of the human foot. These cuneiforms are called, from
+their size, commencing internally, by the names small and
+great cuneiform.</p>
+
+<p>The calcaneum is long and narrow; it is longer than that
+of the horse; it is on the anterior and external part that
+the bone (coronoid tarsal bone) which represents the inferior
+extremity of the fibula is situated. It forms the prominence
+known as <i>the point of the ham</i>, a prominence which is no
+other than the heel, which, in the unguligrades, is, as we
+have already said, very far removed from the ground.</p>
+
+<p>The astragalus, which is elongated in the vertical direction,
+has three articular surfaces disposed in the form of
+trochle&aelig;: a superior trochlea, which is in contact with the
+skeleton of the leg, and which is present in all animals; an inferior,
+which replaces the articular head found on the anterior
+aspect of the astragalus in man; this articulates with the
+portion of the scaphoido-cuboid that corresponds to the
+scaphoid; and, lastly, a posterior trochlea with which the
+calcaneum articulates. Of these three trochle&aelig;, the superior
+is the most strongly marked. Between this latter and the
+inferior is found, on the anterior surface of the astragalus,
+a deep depression, which, during flexion of the foot on the
+leg, receives a prominence which the inferior extremity of
+the tibia presents in its median portion.</p>
+
+<p>We can easily recognise the trochle&aelig; which we have been
+discussing, in the little bones which children use &#8216;to play
+at bones&#8217;; these bones are no other than the astragali of
+sheep.</p>
+
+<p><span class="pagenum"><a name="Page_99" id="Page_99">[99]</a></span>We have already mentioned that the scaphoid and the
+cuboid are ankylosed; they form by their union an irregular
+bone, on which the astragalus and calcaneum are supported.</p>
+
+<p>The cuneiforms articulate with the internal half of the
+superior extremity of the principal metatarsal; the external
+half of this metatarsal articulates with the portion of
+bone which represents the cuboid.</p>
+
+<p>The metatarsus is represented by a principal metatarsal,
+formed by the coalescence of two metatarsals; we also find
+in this region a very small rudimentary metatarsal.</p>
+
+<p>The metatarsus is a little longer than the metacarpus; its
+transverse measurement is a little less; on the other hand,
+it is a little thicker in antero-posterior direction; from these
+two differences it results that the body of the metatarsus
+is quadrilateral, whereas the metacarpus presents only an
+anterior and a posterior surface.</p>
+
+<p>The rudimentary metatarsal is a very small roundish
+bone, situated at the back of the superior extremity of the
+principal metatarsal.</p>
+
+<p>The phalanges closely resemble those of the anterior limbs;
+nevertheless, the first and second phalanges differ from the
+latter in the fact that they are a little longer and narrower.</p>
+
+<p>At the back of the metatarso-phalangeal articulations, as
+in the corresponding region of the anterior limbs, are found
+the sesamoid bones. Such also exist at the articulations of
+the second and third phalanges.</p>
+
+<p><b>Unguligrades: Horse</b> (<a href="#Fig040">Fig. 40</a>, p. 64).&mdash;The pelvis of
+the horse presents a general form which sharply differentiates
+it from that of the carnivora; in fact, the ilium is twisted in
+such a way that the external iliac fossa does not look outwards,
+but upwards. It results from this twist that the anterior
+iliac spine, which we have seen to be directed downwards in
+the carnivora, has become external; and this prominence is
+much farther removed from the vertebral column than in
+the dog or cat. On the other hand, the posterior iliac spine,
+which is directed upwards in the carnivora, has become
+internal; it is also placed nearer to the vertebral column,
+with the result that the distance which separates this spine<span class="pagenum"><a name="Page_100" id="Page_100">[100]</a></span>
+from that of the bone of the opposite side is proportionately
+less.</p>
+
+<p>The internal iliac spine, which is conical in shape, and
+curved upwards, forms a prominence known as <i>the angle of
+the crupper</i>; the external iliac spine, thick and provided
+with tuberosities, forms a clearly-defined prominence; this is
+the angle of the <i>haunch</i>.</p>
+
+<p>The iliac crest, extending directly from one spine to the
+other, is curved, its concavity being turned upwards. The
+external iliac fossa, which looks upward, is limited anteriorly
+by this crest, and is, like the latter, slightly hollowed. The
+portion of the bone which connects the ilium to the region
+occupied by the cotyloid cavity is extremely narrow; posteriorly,
+the bone enlarges again to form the ischial and
+pubic portions.</p>
+
+<div class="figmed"><a name="Fig053" id="Fig053"></a>
+<img src="images/illo124.png" alt="Fig. 53" width="400" height="342" />
+<p class="caption just">Fig 53.&mdash;Pelvis of the Horse: Superior Surface.</p>
+
+<p class="subcaption just">1, Iliac crest; 2, external iliac fossa; 3, sacrum; AA&#8242;, bi-iliac diameter;
+BB&#8242;, bi-ischiatic diameter.</p></div>
+
+<p>The tuberosity of the ischium, thick and curved upwards,
+but less so than in the ox, forms the most prominent part of
+the posterior border of the region of the thigh; this projecting
+portion, so sharply defined in spare subjects, is known
+as the <i>point</i> or <i>angle of the buttock</i>. Contrary to what we have
+indicated in the case of the dog, the distance which separates
+the ischiatic tuberosities is inconsiderable in proportion to
+that which we find between the external iliac spine of one
+side and that of the opposite. The bi-ischiatic diameter
+does not even equal the width of one iliac bone measured
+at the level of its crest (<a href="#Fig053">Fig. 53</a>). On the skeleton of the
+horse in the &Eacute;cole des Beaux-Arts, the distance which separates
+the tuberosities of the ischia is 225 millimetres; that
+between the two spines of each iliac bone is 25 centimetres.</p>
+
+<p>The anterior region of the crupper is thus much broader
+than that occupied by the ischia.</p>
+
+<p>The femur is relatively short. Its shaft is rectilinear, and
+does not present the anterior convexity which is found on
+the human femur, and which we indicated when discussing
+that of the dog. The shaft of the bone, instead of being
+prismatic and triangular, presents four surfaces; the
+anterior, internal, and external, almost pass into each other,
+being separated one from the other merely by rounded
+and slightly marked borders; the posterior surface, which<span class="pagenum"><a name="Page_101" id="Page_101">[101]</a></span>
+is plane, replaces the linea aspera, which in the horse, instead
+of presenting the appearance of a crest, is considerably
+widened. The numerous irregularities which this surface
+presents give insertion to the muscles which correspond to
+those attached to the linea aspera.</p>
+
+<p>Between this posterior surface and the external is found
+a rough prominence which curves forward; this was designated
+by Cuvier the <i>third trochanter</i>; it replaces the external
+branch of the superior line of bifurcation of the linea aspera;
+other authors call it the <i>infratrochanteric crest</i>, because it is
+situated below the great trochanter. At the inferior part of
+the same region is found a deep fossa, the borders of which
+are rough; this is the <i>supracondyloid fossa</i>.</p>
+
+<p>Between the posterior surface and the internal are found:
+above, the lesser trochanter, which is long and rough;
+below, at the level of the supracondyloid fossa, an equally
+rough surface known by the name of the <i>supracondyloid
+crest</i>.</p>
+
+<p>The superior extremity is flattened from before backwards.
+The neck is not well marked. The great trochanter is very
+prominent, and projects beyond the level of the head of the
+femur. We divide the great trochanter into three parts:
+the summit, which is the most elevated portion; the convexity,<span class="pagenum"><a name="Page_102" id="Page_102">[102]</a></span>
+which is situated in front; and the crest, formed by
+muscular impressions, situated outside and below the convexity.
+The digital fossa is situated behind and below the
+summit of the great trochanter. With regard to the lesser
+trochanter, it is placed so far down that it really forms
+part of the shaft of the bone, with which, besides, we have
+described it.</p>
+
+<p>On the inferior extremity of the femur are two condyles
+and a trochlea; the condyles are clearly separated from this
+latter by a marked constriction.</p>
+
+<p>The trochlea is directed with a slight obliquity downwards
+and inwards; its internal lip is much thicker and more
+prominent than the external; this is, accordingly, a condition
+exactly the opposite of that which characterizes the
+corresponding region of the human femur.</p>
+
+<p>The knee-cap is lozenge-shaped; its superior angle projects
+upward, and produces a prominence at the part which
+corresponds to the base of the human patella, the part
+which is here the thickest portion of the bone. Its anterior
+surface is convex and rough. Its posterior surface presents
+two lateral articular facets, separated by a crest; this
+surface is in contact with the trochlea of the femur, and,
+as it is the internal lip of the latter which is the more
+developed, it results therefrom that the internal articular
+surface of the knee-cap is larger than the external.</p>
+
+<p>The knee-cap contributes to the formation of the region of
+the posterior limb which is called the <i>stifle</i>.</p>
+
+<p>The tibia is large in its upper portion; in its inferior part
+it is flattened from before backwards. The posterior surface
+of the shaft presents an oblique line, below which are found
+vertical rough lines for the insertion of muscles. The external
+surface is hollowed out in its upper part. The
+anterior tuberosity of the tibia rises just to the level of the
+flat articular surface; it is hollowed in its median portion
+by a vertical groove of elongated form, which receives the
+ligament that binds the knee-cap to the tibia. The external
+tuberosity is more prominent than the internal; in it is
+found a groove for the passage of the anterior tibial muscle.</p>
+
+<p>The inferior extremity, flattened from before backwards,<span class="pagenum"><a name="Page_103" id="Page_103">[103]</a></span>
+presents a surface which is moulded on the trochlea of the
+astragalus; the median crest of this surface is thick, and
+descends lower posteriorly than the tuberosities which are
+situated on the external and internal aspects of this
+extremity.</p>
+
+<p>Of the two tuberosities, that which is internal is comparable
+to the internal malleolus of man, the one on the outer
+side forms a sort of external malleolus; but this latter here
+belongs to the tibia, and not to the fibula.</p>
+
+<p>The fibula, in fact, does not reach the inferior extremity
+of the tibia; it is a poorly developed bone, elongated and
+terminating inferiorly in a point, at the middle of the shaft
+of the tibia or at its lower third. Its superior extremity,
+which is slightly expanded, articulates with the tuberosity
+which occupies the outer aspect of the corresponding extremity
+of the tibia.</p>
+
+<div class="figmed"><a name="Fig054" id="Fig054"></a>
+<img src="images/illo127.png" alt="Fig. 54" width="200" height="354" />
+<p class="caption just">Fig. 54.&mdash;Tarsus of the Horse: Left Posterior Limb, Anterior
+Surface.</p>
+
+<p class="subcaption just">1, Tibia; 2, internal tuberosity of the inferior extremity of the tibia
+(homologue of the internal malleolus of man); 3, external tuberosity
+of the inferior extremity of the tibia (homologue of the external malleolus);
+4, median crest lodged in the groove of the pulley of the astragalus; 5,
+pulley of the astragalus; 6, internal tuberosity of the astragalus; 7,
+calcaneum; 8, cuboid; 9, scaphoid; 10, great cuneiform, the small cuneiform
+is placed behind this latter; 11, principal metatarsal; 12, external
+rudimentary metatarsal. The internal rudimentary metatarsal, being
+more slender than the external, does not appear in the figure.</p></div>
+
+<p>The bones of the tarsus are six in number: the calcaneum
+and astragalus form the upper row; the cuboid, scaphoid,
+and two cuneiforms form the lower (<a href="#Fig054">Fig. 54</a>).</p>
+
+<p>The astragalus has not, as in ruminants, an inferior
+trochlea for articulation with the scaphoid; this portion of
+the bone presents a surface which is slightly convex. It
+articulates with the tibia by a trochlea that occupies not only
+the superior surface, but also the anterior. This trochlea,
+which is directed slightly obliquely downwards and outwards,
+has a very pronounced form; its lips, which are extremely
+prominent, determine by their anterior part one of the
+features which we recognise on the anterior aspect of the
+<i>ham</i>&mdash;a feature which is still more accentuated when the
+metatarsus (<i>canon</i>) is extended on the leg. On the internal
+surface of the astragalus is found a tubercle, which forms a
+projection in the corresponding region of the ham.</p>
+
+<p>The calcaneum, which is not quite so long as that of
+the ox, forms by its summit a prominence which is called
+<i>the point of the ham</i>.</p>
+
+<p>The cuboid is small; the scaphoid is large, and flattened
+from above downwards. Of the two cuneiforms, the more
+external is the larger; it closely resembles the scaphoid;
+it is flattened from above downwards as is the latter; but<span class="pagenum"><a name="Page_104" id="Page_104">[104]</a></span>
+it is a little smaller in size. The small cuneiform, which
+occupies the inner side of the tarsus, is the smallest bone in
+this region; it is sometimes divided into two parts; this
+raises the number of the cuneiforms to three, and that of the
+bones of the tarsus to seven.</p>
+
+<p>The bones of the metatarsus and the phalanges are equal
+in number to the corresponding bones in the anterior limbs;
+they are formed on a type analogous to that of these latter.
+Accordingly, we shall merely indicate the differences which
+characterize them.</p>
+
+<p>The principal metatarsal is longer than the metacarpal of<span class="pagenum"><a name="Page_105" id="Page_105">[105]</a></span>
+the same class; its shaft is more cylindrical; its inferior
+extremity is somewhat thicker. The external rudimentary
+metatarsal is better developed than the internal; in the
+metacarpus the reverse is the case.</p>
+
+<p>The phalanges so far resemble those of the anterior limb
+that, as differential characters, we need point out only the
+following: the first phalanx of the hind-foot is a little
+shorter than that of the fore-foot; its inferior extremity
+is a little narrower, and its superior extremity a little
+thicker. The second phalanx is a little less expanded
+laterally.</p>
+
+<p>The difference in appearance which the three phalanges,
+anterior and posterior, respectively present are to be borne
+in mind; for they are correlated to the general form of the
+fore and hind feet. We will establish this point when we
+come to study the hoof (see <a href="#Fig101">Figs. 101</a> and <a href="#Fig102">102</a>, p. 257). In
+the fore-foot the ungual phalanx has its inferior surface
+limited externally by a circular border, while the same bone
+of the hind-foot has this surface a little narrower, more concave,
+and limited by two curved borders which unite
+anteriorly to form an angle&mdash;an arrangement which gives to
+the general outline of this region the form of the letter V.</p>
+
+<h5>Articulation of the Posterior Limbs</h5>
+
+<p><b>The Coxo-femoral Articulation.</b>&mdash;The head of the
+femur is received in the cotyloid cavity; these are the osseous
+surfaces in contact in this articulation. They are maintained
+in position by a fibrous capsule and a round ligament.
+To this latter is found attached, in the horse, a fasciculus
+which, commencing, as does the round ligament, at the depression
+on the head of the femur, emerges from the cotyloid
+cavity by the notch which is present in its circumference,
+and is attached to the anterior border of the pubes, to blend
+with the tendon of the rectus muscle of the abdomen. This
+is the pubio-femoral ligament.</p>
+
+<p>The movements which this joint permits are the same in
+the quadrupeds as in man, but less extensive. They are:
+flexion and extension, abduction and adduction, the two<span class="pagenum"><a name="Page_106" id="Page_106">[106]</a></span>
+latter being much more limited than the former. There is
+also rotation.</p>
+
+<p>By flexion, the inferior extremity of the femur is directed
+forwards; the bone of the thigh then takes a more oblique
+direction than the normal. This movement takes place, for
+example, when the animal carries forward one of its hinder
+limbs. Extension, which takes place in an inverse sense, is
+produced when the foot is fixed on the ground, while the
+body is projected forward. It is also produced in the
+action of kicking.</p>
+
+<p>As for the lateral movements&mdash;viz., abduction and adduction&mdash;they
+are less extensive than the preceding movements.
+The absence of the pubio-femoral ligament in other
+quadrupeds than the horse explains why in them abduction
+is less limited than in the latter. Indeed, it is the tension of
+this ligament, occasioned by the abduction of the thighs,
+which arrests more quickly the movement in question.</p>
+
+<p><b>Articulation of the Knee.</b>&mdash;This articulation, as in man,
+is formed by the femur, the patella, and the tibia.</p>
+
+<p>In the horse the ligament of the patella is not single, but
+consists of three parts, designated, on account of their
+position, by the respective names of external, internal, and
+median patellar ligaments. The two former come from the
+angles on the corresponding borders of the knee-cap; the
+median springs from the anterior surface and inferior angle of
+the same bone. They all three pass to their termination on
+the anterior tubercle of the tibia. The external ligament
+is the strongest, and the internal ligament the least
+developed.</p>
+
+<p>In the dog, the cat, the pig, and the sheep, the patellar
+ligament consists of a single band. The articulation is
+further strengthened on the sides by lateral ligaments&mdash;an
+internal and an external.</p>
+
+<p>With regard to the principal movements, these are flexion
+and extension, to which may be added movements of rotation
+of limited extent. In flexion, the leg bends on the thigh;
+its inferior extremity is directed upwards and backwards;
+the angle which the tibia naturally forms with the femur
+becomes less obtuse.</p>
+
+<p><span class="pagenum"><a name="Page_107" id="Page_107">[107]</a></span>But
+it should be understood that one part of this description&mdash;that
+which has relation to the leg&mdash;holds good
+only when the femur is in its normal condition, or in flexion.
+Indeed, at the close of the movement in which, during a step,
+the foot is in contact with the ground&mdash;that is, at the termination
+of the resting stage&mdash;the inferior extremity of the tibia
+is directed backwards. But the femur is then in a state of
+extension, and in regard to this latter the attitude of the
+leg is unchanged.</p>
+
+<div class="figmed"><a name="Fig055" id="Fig055"></a>
+<img src="images/illo130.png" alt="Fig. 55" width="225" height="371" />
+<p class="caption just">Fig. 55.&mdash;Extension of the Leg: Right Posterior Limb of the
+Horse, External Surface. (After a Chronographic Study by
+Professor Marey.)</p></div>
+
+<p>At this moment, notwithstanding the direction, which
+recalls that which it has at the time of flexion, the leg is not
+bent on the thigh; on the contrary, it is almost in the line
+of its continuation (<a href="#Fig055">Fig. 55</a>). As we have done in connection
+with the articulations of the anterior limbs, we borrow
+this figure from the interesting chronophotographic studies
+of Professor Marey.<a name="FNanchor_17_17" id="FNanchor_17_17"></a><a href="#Footnote_17_17" class="fnanchor">[17]</a></p>
+
+<div class="footnote"><p><a name="Footnote_17_17" id="Footnote_17_17"></a><a href="#FNanchor_17_17"><span class="label">[17]</span></a>
+E. J. Marey, &#8216;Analysis of the Movements of the Horse by the Chronophotograph&#8217;
+(<i>La Nature</i>, June 11, 1898).</p></div>
+
+<p><b>The Tibio-tarsal Articulations and of the Bones of the
+Tarsus.</b>&mdash;In the region which veterinary anatomists call the
+ham, the articulations of the leg and foot alone call for special<span class="pagenum"><a name="Page_108" id="Page_108">[108]</a></span>
+study in the case of the horse. The articulations of the
+bones of the tarsus, and of these with the metatarsus, do not
+offer any interest with regard to mobility, this being almost
+wholly absent at that level.</p>
+
+<p>The leg and the astragalus, in a general way, are placed in
+contact by such articular surfaces that the resulting joint,
+which is a true hinge, permits movements of flexion and extension
+only. Indeed, as we have indicated above, the tibia
+is furnished, on the inferior surface, with a crest that fits into
+the deep groove which is situated on the corresponding
+surface of the astragalus.</p>
+
+<p>During flexion, the anterior surface of the foot tends to
+approach the anterior surface of the leg, the angle formed
+by these two segments becoming more and more narrowed.
+The displacement in the opposite direction characterizes
+extension.</p>
+
+<p>In other quadrupeds, the articulations which bind together
+the bones of the tarsus possess a little more freedom of movement.
+The shape of these bones, and particularly the shape
+of the surfaces of the astragalus, which are in contact with
+them, allow movements in this region, in the case of the dog
+and cat, which, without being so extensive as those of the
+human foot, in the subastragaloid articulation, nevertheless,
+recall the mobility which we find in the human species
+at this level&mdash;that is to say, rotation, abduction, and
+adduction of the foot.</p>
+
+<p>As for the articulations of the metatarsus with the
+phalanges, and of the phalanges with one another, they resemble
+those of the anterior limb too closely that it should
+be necessary to study them here. Such a study would
+be, in this case, but a repetition (see <a href="#Page_76">p. 76</a>, a description of the
+articulations in question).</p>
+
+<h4>THE HEAD IN GENERAL, AND IN SOME
+ANIMALS IN PARTICULAR.</h4>
+
+<p>When we compare, by the examination of one of their
+lateral aspects, the skull of man and the same region in other
+mammals, it is easy to observe that the relative development
+of the cranium and face is entirely different. In the<span class="pagenum"><a name="Page_109" id="Page_109">[109]</a></span>
+case of man the cranium is large, and the face relatively
+small; in animals the face is proportionally much more
+highly developed. The measure of the facial angle permits
+us to note these differences, and the figures relative to the
+value of this angle are sufficiently demonstrative to induce us
+to indicate those which are, in a general way, connected with
+some of the forms in individuals which here occupy our
+attention. In the first place, we must remember that the
+angle in question is more acute, as the cranium is less developed
+in proportion to the facial region (<a href="#Fig056">Figs. 56</a> and <a href="#Fig057">57</a>). It
+is especially to this character that we wish to draw attention.</p>
+
+<table summary="Table page 109">
+
+<tr>
+<td class="left padr5">Man</td>
+<td class="right">70&deg;</td>
+<td class="left">-80&deg;</td>
+</tr>
+
+<tr>
+<td class="left padr5">Cat</td>
+<td class="right">41&deg;</td>
+<td>&nbsp;</td>
+</tr>
+
+<tr>
+<td class="left padr5">Dog</td>
+<td class="right">28&deg;</td>
+<td class="left">-41&deg;</td>
+</tr>
+
+<tr>
+<td class="left padr5">Sheep</td>
+<td class="right">20&deg;</td>
+<td class="left">-25&deg;</td>
+</tr>
+
+<tr>
+<td class="left padr5">Ox</td>
+<td class="right">18&deg;</td>
+<td class="left">-20&deg;</td>
+</tr>
+
+<tr>
+<td class="left padr5">Ass</td>
+<td class="right">12&deg;</td>
+<td class="left">-16&deg;</td>
+</tr>
+
+<tr>
+<td class="left padr5">Horse</td>
+<td class="right">11&deg;</td>
+<td class="left">-13&deg;</td>
+</tr>
+
+</table>
+
+<div class="figmed"><a name="Fig056" id="Fig056"></a>
+<img src="images/illo133a.png" alt="Fig. 56" width="350" height="287" />
+<p class="caption just">Fig. 56.&mdash;Human Skull: Measure of the Facial Angle by the
+Method of Camper. Angle BAC = 80&deg;.</p>
+
+<p class="subcaption just">The internal wall of the cranial cavity is marked by the dotted line.</p></div>
+
+<div class="figmed"><a name="Fig057" id="Fig057"></a>
+<img src="images/illo133b.png" alt="Fig. 57" width="400" height="360" />
+<p class="caption just">Fig. 57.&mdash;Skull of the Horse: Measure of the Facial Angle by
+the Method of Camper.<a name="FNanchor_18_18" id="FNanchor_18_18"></a><a href="#Footnote_18_18"
+class="fnanchor" style="font-size: 100%; vertical-align: 20%;">[18]</a> Angle BAC = 13&deg;.</p>
+
+<p class="subcaption just">The internal wall of the cranial cavity is shown by the dotted line.</p></div>
+
+<div class="footnote"><p><a name="Footnote_18_18" id="Footnote_18_18"></a><a
+href="#FNanchor_18_18"><span class="label">[18]</span></a> We have indicated on this sketch of the skull of the horse the facial
+angle measured by the method of Camper, in order that the correspondence
+with <a href="#Fig056">Fig. 56</a> may be more complete. But it is certain that the procedure
+here employed is in practice not satisfactory, since the apex of the angle,
+as we can demonstrate, is found to be situated within the contour of
+the head, and that, consequently, it is rather difficult to localize it precisely
+in the case of a given skeleton. Further, because of the absence of the
+base of the nose in the complete skull, the auriculo-nasal line cannot
+be accurately fixed. It would be the same for most other animals. This
+is why the method employed for these latter is preferably that of Cuvier,
+or, again, that of Cloquet. In the former, the apex of the angle of
+Camper is transferred to the free border of the upper incisors, but these
+teeth may be absent, and, on the other hand, ruminants are destitute of
+them. In the second, the same apex is placed at the alveolar border,
+and the angle then becomes fairly easy to appreciate.</p></div>
+
+<p>Besides, in animals the cranium is very prominent
+superiorly, and the face, more or less elongated, is sharply
+projected downwards and forwards; in man the cranial region
+occupies not only the superior, but also the posterior part;
+the face is short and of a compact form. The human head,
+in its general aspect, may be compared to a sphere, while
+the skull of the quadrupeds presents the aspect of a quadrangular
+pyramid, with the base turned upwards and the
+summit at the incisor teeth.</p>
+
+<p><b>Direction of the Head.</b>&mdash;Before entering on the study
+of the bones of the head, it is necessary, in our opinion, to
+agree as to the position in which we shall suppose it to be
+placed.</p>
+
+<p>The question may seem to be one of little importance;
+nevertheless, it cannot be regarded as indifferent, since
+authors are not all agreed on this subject.</p>
+
+<p>Some suppose it to be placed vertically&mdash;that is, with the
+incisor teeth turned directly downwards. Others, on the
+contrary, suppose it to be placed horizontally, resting on the
+whole length of the lower jaw, the face being then turned
+upwards. These two extreme methods of arrangement appear<span class="pagenum"><a name="Page_110" id="Page_110">[110]</a></span>
+to us to possess inconveniences&mdash;at least, for comparison
+with the human head.</p>
+
+<p>Indeed, if, when the head is vertical, the same regions of the
+face (forehead, nose) are, in the case of animals as well as man,
+turned forward, the lower jaw ceases to merit its appellation,
+as it is then situated, not below, but behind the upper.<span class="pagenum"><a name="Page_111" id="Page_111">[111]</a></span>
+Furthermore, if this position is chosen, for example, for modelling
+or drawing, it cannot be obtained without difficulty
+when we have to deal with an isolated piece of the skeleton,
+on account of the absence of equilibrium, which it is necessary
+to obviate. It is true that the question of convenience
+should not take precedence of all others, and it suffices for
+us in this connection to recall, in regard to the human pelvis,
+that, although the older anatomists used to represent it as
+resting commodiously on the three angles which terminate
+it at its lower part (ischial tuberosities and coccyx), this
+attitude being false, it is customary now to incline the
+superior aspect forwards, inasmuch as this arrangement
+more nearly conforms to reality, in spite of the fact that it
+is a little more difficult so to dispose an isolated pelvis.
+Further, to return to the head; if its vertical direction can
+be demonstrated, for example, in many horses, it is not sufficiently
+general to be adopted as the classic position.</p>
+
+<p>In regard to the facility of placing in position, the horizontal
+direction is certainly to be preferred; but this is also
+far removed from the natural position in the animal while in
+the state of repose. On the other hand, the mind is not
+satisfied with the idea that certain regions of the face,
+such as the nose and the forehead, are then directed upwards.
+And yet it is necessary to come to a decision, seeing that
+what we are now investigating applies also to the position
+to which it is necessary to give the preference in placing the
+skeleton of the head when we wish to draw it in profile.
+That which we adopt is a compromise, but to us it seems
+more rational.</p>
+
+<p>The position of the head of the horse, to be normal,
+should be such as to give it an inclination of 45&deg;. In this<span class="pagenum"><a name="Page_112" id="Page_112">[112]</a></span>
+case the lower jaw is still posterior; and, for this reason, we
+see in adopting this position some inconveniences from a
+didactic point of view. Accordingly, we will suppose the
+head brought a little nearer to the horizontal, and this, from
+the imaginative point of view, has certainly an advantage
+which we cannot afford to neglect when addressing artists.</p>
+
+<p>Indeed, let us suppose that to a clay model of a human
+head we wish to give the aspect of the head of a quadruped.
+We should elevate the occiput; and then, taking hold of the
+lower part of the face, we should lengthen it, not in a direction
+precisely antero-posterior, but downwards and forwards. It
+is obviously this latter procedure which, on the other
+hand, is carried out when a person wishes to give to his
+own face some resemblance to the muzzle of a quadruped.</p>
+
+<p>It is true that, in the position we have adopted, the face
+is directed obliquely downwards and forwards, and that there
+may result a certain confusion in describing the position
+of its different parts. On this account, with the object
+of not making complications, we purpose, for the present,
+to substitute, for example, for the term &#8216;antero-superior&#8217;&mdash;which
+when speaking of the position of the forehead and
+nose would be more exact&mdash;the term &#8216;anterior,&#8217; which is
+sufficiently comprehensible. The mouth will be, for the
+same reason, referred to as being situated at the inferior
+part of the face, and not the antero-inferior.</p>
+
+<p><b>The Skull.</b>&mdash;The elevation of the cranial region becomes
+especially appreciable when we examine the occipital
+bone. Before verifying this fact, it is not superfluous to
+recall the general arrangement which this bone presents in
+the human skull. A portion of the occipital bone occupies
+the base of the skull; but this base in man is horizontal; to
+this region succeeds the shell-shaped portion of the occipital
+bone, which, passing vertically upwards, forms with the
+preceding portion an angle situated at the level of the external
+occipital protuberance, and of the curved line which
+starts from it on each side. In animals a portion of the
+occipital bone is horizontal, it is true; but this bone being
+sharply bent at the level of the occipital foramen and condyles,
+the result is that the portion which surmounts these latter<span class="pagenum"><a name="Page_114" id="Page_114">[114]</a></span>
+looks backwards, and is limited above by the external
+occipital protuberance, which forms the culminating
+point of the skull; this point is situated between the
+ears.</p>
+
+<div class="figmed"><a name="Fig058" id="Fig058"></a>
+<img src="images/illo136a.png" alt="Fig. 58" width="500" height="349" />
+<p class="caption just"><span class="pagenum"><a name="Page_113" id="Page_113"></a></span>Fig.
+58.&mdash;Skull of one of the Felid&aelig; (Jaguar): Left Lateral Aspect.</p>
+
+<p class="subcaption just">1, Posterior surface of the occipital bone; 2, external occipital
+protuberance; 3, condyle of the occipital bone; 4, jugular process;
+5, parietal bone; 6, frontal bone; 7, orbital process; 8, orbital cavity;
+9, squamous portion of the temporal bone; 10, external auditory canal,
+in front of which is situated the zygomatic process; 11, tympanic bulla;
+12, superior maxillary bone; 13, intermaxillary or incisor bone; 14,
+nasal bone; 15, anterior orifice of the nasal cavity; 16, malar bone;
+17, ungual or lachrymal bone; 18, inferior maxillary bone; 19, condyle
+of the inferior maxillary bone; 20, coronoid process; 21, incisor teeth;
+22, canine teeth; 23, molar teeth.</p></div>
+
+<div class="figmed"><a name="Fig059" id="Fig059"></a>
+<img src="images/illo136b.png" alt="Fig. 59" width="450" height="250" />
+<p class="caption just">Fig. 59.&mdash;Skull of the Lion: Left Lateral Aspect.</p>
+
+<p class="subcaption just">This figure is intended to show that in the lion the contour of the face
+between the nasal bones and the cranial region is more flattened than
+in other felid&aelig;, such as the tiger, jaguar, panther, and domestic cat.
+This difference is shown by comparison of this figure with the preceding
+one (<a href="#Fig058">Fig. 58</a>). We are indebted to M. Tramond, the well-known
+naturalist, for the indication of this differential character which, from
+the artistic plastic point of view, is one of real interest.</p></div>
+
+<p>This protuberance, prolonged on each side by the superior
+curved line of the occipital bone, is so much the more
+prominent as this bone bends sharply a second time, so
+as to form a third portion, which, looking forwards, forms
+part of the anterior aspect of the skull, and proceeds to
+articulate with the parietals. On this third portion is
+found a crest which, proceeding from the occipital protuberance,
+is continuous in front with the <a href="#ParietalCrest">parietal crests</a>,
+to which we will again refer in speaking of the parietal
+bones.</p>
+
+<p>On the inferior surface of the human occipital bone are
+found, at the level of, and external to, the condyles two bony
+elevations which bear the name of <i>jugular eminences</i>. They
+are long in quadrupeds, and constitute what are designated
+by some authors the <i>styloid processes</i>, but they must
+not be confounded with the processes of the same name
+which in the case of man form part of the temporal bone.
+These processes are very highly developed in the pig, horse,
+ox, and sheep.</p>
+
+<p>In the ox, the occipital bone is deprived of the protuberance,
+and is not bent on itself in the anterior portion,
+neither does it form the most salient part of the skull; this
+latter, which is situated at the level of the horns, belongs
+to the frontal bone. In the pig, also, the occipital bone
+is not bent upon itself in its anterior portion, but forms
+the summit of the head. The occipital protuberance,
+hollowed on its posterior surface, rises vertically, and
+rests upon the parietal bone, with which it forms an acute
+angle.</p>
+
+<p>The parietals, two separate bones in the dog and the
+cat, but fused in the median line in the ox, sheep, and horse,
+are of special interest in regard to the two crests which, in
+the carnivora, and also in the pig and the horse, occupy
+their external surface, and, after diverging from one
+another, are continued by a crest which crosses the frontal<span class="pagenum"><a name="Page_115" id="Page_115">[115]</a></span>
+bone and ends at the external orbital process of the latter
+bone.</p>
+
+<p><a name="ParietalCrest" id="ParietalCrest"></a>These crests, known as the <i>parietal</i> or <i>temporal crests</i>,
+recall both in position and relations the temporal curved
+line of the parietal bone of man. They contribute, as in
+the case of the latter, to the formation of the boundaries
+of the temporal fossa.</p>
+
+<div class="figmed"><a name="Fig060" id="Fig060"></a>
+<img src="images/illo138.png" alt="Fig. 60" width="450" height="328" />
+<p class="caption just">Fig. 60.&mdash;Skull of the Dog: Left Lateral Aspect.</p>
+
+<p class="subcaption just">1, Posterior surface of the occipital bone; 2, external occipital protuberance;
+3, occipital condyle; 4, jugular process; 5, parietal bone;
+6, frontal bone; 7, orbital process; 8, orbital cavity; 9, external auditory
+canal, in front of which is found the zygomatic process; 10, tympanic
+bulla; 11, superior maxillary bone; 12, intermaxillary or incisor bone;
+13, nasal bone; 14, anterior opening of the cavity of the nasal foss&aelig;;
+15, malar bone; 16, lachrymal bone; 17, inferior maxillary bone; 18, condyle
+of the inferior maxillary bone; 19, coronoid process; 20, incisor
+teeth; 21, canine teeth; 22, molar teeth.</p></div>
+
+<p>In the carnivora, these crests are situated, throughout their
+whole length, in the median line, the temporal foss&aelig; being,
+accordingly, as extended as they possibly can be. In certain
+species, the development of these crests is such that they
+form by their union a vertical plate, which, in separating the
+two temporal foss&aelig;, gives them a greater depth. In the pig,
+the parietal crests, analogous in this respect to the temporal
+curved lines of the parietal bones of man, are separated by<span class="pagenum"><a name="Page_116" id="Page_116">[116]</a></span>
+an interval, proportionately less extended, however, than
+that of the human skull. The parietal bone in the ox and the
+sheep does not enter into the formation of the anterior surface
+of the skull; it is formed by an osseous plate, narrow and
+elongated transversely, which, with the occipital bone, constitutes
+the base of the region of <i>the nape of the neck</i>. It is
+bent upon itself at the level of its lateral portions so as to
+occupy the temporal fossa.</p>
+
+<p>The anterior surface of the frontal bone, which is depressed
+in the median line in the dog, but plane in the horse, is
+limited by two crests, which, situated on the prolongation
+of the parietal crests, diverge more and more from one
+another in proportion as they occupy a lower position.
+This surface terminates externally in two processes, which
+are the homologues of the external orbital processes of the
+human frontal bone.</p>
+
+<p>The superior border of these orbital processes, situated
+on the prolongation of the corresponding parietal crests,
+contributes to limit the temporal fossa. Each of these
+orbital processes terminates in the following manner: In the
+bear, dog, cat, and pig, in which the orbital cavities are incompletely
+bounded by bone, this process, slightly developed,
+is not in connection, by its inferior extremity, with any other
+part of the skeleton of the region. In the ox and the sheep,
+it articulates with a process of the malar bone. In the
+horse, it articulates with the zygomatic process of the
+temporal bone. The inferior margin of this process forms
+a part of the boundary of the anterior opening of the orbital
+cavity.</p>
+
+<p>The supra-orbital foramen, which does not exist in carnivora,
+occupies in the horse the base of the orbital process. In
+the ox, it is situated a little nearer the middle line; and its
+anterior orifice opens into an osseous gutter which is directed
+upwards towards the base of the horn, while inferiorly it
+meets the inferior border of the frontal bone; in the sheep this
+groove is but slightly developed. In this latter, as in the ox,
+it is the frontal bone which forms the most elevated portion
+of the skull. In fact, being bent upon itself at a certain level,
+its external surface is formed of two planes: one, posterior,<span class="pagenum"><a name="Page_117" id="Page_117">[117]</a></span>
+which is inclined downwards and directed backwards; the
+other, anterior, is also inclined downwards, but with a forward
+obliquity. At the union of these planes the bone forms an
+elbow, on either side of which are found the osseous processes
+on which the horns are mounted.</p>
+
+<div class="figmed"><a name="Fig061" id="Fig061"></a>
+<img src="images/illo140.png" alt="Fig. 61" width="450" height="415" />
+<p class="caption just">Fig. 61.&mdash;Skull of the Pig: Left Lateral Aspect.</p>
+
+<p class="subcaption just">1, Occipital bone; 2, condyle of the occipital; 3, jugular process;
+4, parietal bone; 5, parietal crests; 6, frontal bone; 7, orbital process;
+8, orbital cavity; 9, external auditory canal; 10, zygomatic process;
+11, superior maxillary bone; 12, intermaxillary or incisor bone; 13,
+nasal bone; 14, anterior orifice of the cavity of the nasal foss&aelig;; 15,
+malar bone; 16, lachrymal bone; 17, inferior maxillary bone; 18, condyle
+of the inferior maxillary bone; 19, incisor teeth; 20, canine teeth;
+21, molar teeth.</p></div>
+
+<p>In the bear, the anterior margin of the frontal bone is
+prolonged by two small tongues of bone, which, descending
+on the lateral borders of the nasal bones, articulate with the
+superior half of the latter.</p>
+
+<p>The temporal bone is, as in man, furnished with a squamous<span class="pagenum"><a name="Page_118" id="Page_118">[118]</a></span>
+portion, from which springs the zygomatic process, which
+is directed towards the face, to terminate in the following
+manner: in the carnivora, the pig, and ruminants, it
+articulates with the malar bone by its inferior border;
+in the horse, it insinuates itself as a sort of wedge between
+the malar bone and the orbital process of the frontal bone,
+with which it articulates, as we have already pointed out,
+and contributes, by a portion situated in front of this
+articulation, to form the boundary of the anterior opening
+of the corresponding orbital cavity. As in man, the zygomatic
+process arises by two roots: one, transverse, behind
+which is situated the glenoid cavity of the temporal bone;
+the other, antero-posterior, which proceeds to join above
+with the superior curved line of the occipital bone.</p>
+
+<p>Behind the glenoid cavity is found the external auditory
+canal, and, further back still, the mastoid process. This
+latter, but slightly developed in the carnivora, a little more
+so in the ruminants, and still more in the horse, has its
+external surface traversed by a crest, <i>the mastoid crest</i>,
+which, after becoming blended with the antero-posterior
+root of the zygomatic process, proceeds with this latter to
+join the superior occipital curved line.</p>
+
+<p>Below the auditory canal is situated a round prominence,
+highly developed in carnivora; this is <i>the tympanic bulla</i>,
+also called <i>the mastoid protuberance</i>; it is an appendage of
+the tympanum.</p>
+
+<h5>The Face</h5>
+
+<p>The bone of this region, around which all the others come
+to be grouped, is, as in man, the superior maxillary. The
+relations of this maxillary with the neighbouring bones is
+not exactly the same in all animals; for example, in the ox,
+sheep, and horse, in which the bones of the nose are wide in
+their upper part, and in which the lachrymal bone, which is
+very highly developed, encroaches on the face, the superior
+maxillary does not meet the frontal bone; it is separated
+from it by the above-named bones. It unites with it, on the
+other hand, in the dog and the cat. In the bear, it is separated
+from the bones of the nose by a small tongue of bone which<span class="pagenum"><a name="Page_119" id="Page_119">[119]</a></span>
+springs from the anterior border of the frontal&mdash;a process
+which we have noticed in connection with this latter.</p>
+
+<div class="figmed"><a name="Fig062" id="Fig062"></a>
+<img src="images/illo142.png" alt="Fig. 62" width="450" height="353" />
+<p class="caption just">Fig. 62.&mdash;The Skull of the Ox: Left Lateral Aspect.</p>
+
+<p class="subcaption just">1, Occipital condyle; 2, jugular process; 3, parietal bone; 4, frontal
+bone; 5, osseous process, which serves to support the horn (horn-core);
+6, orbital cavity; 7, external auditory canal, in front of which is found
+the zygomatic process; 8, temporal fossa; 9, superior maxillary bone;
+10, intermaxillary or incisor bone; 11, nasal bone; 12, anterior orifice
+of the cavity of the nasal foss&aelig;; 13, malar bone; 14, lachrymal bone;
+15, inferior maxillary bone; 16, condyle of the inferior maxillary bone;
+17, incisor teeth; 18, molar teeth.</p></div>
+
+<p>In the pig, ox, sheep, and horse, the external surface is
+traversed, to a greater or less extent, by a crest which is
+situated on the prolongation of the inferior border of the
+malar bone. This crest, which is straight in the horse, but
+curved with its convexity upwards in the ox and the sheep,
+is known as <i>the maxillary spine</i> or <i>the malar tuberosity</i>: it
+gives attachment to the masseter muscle, and, in the horse,
+is distinctly visible under the skin. It does not exist in the
+carnivora. On the same surface is situated the sub-orbital
+foramen.</p>
+
+<p>The inferior border is hollowed out into alveoli, in
+which are implanted the superior molar and canine teeth.
+This border is prolonged forwards from the alveolus,<span class="pagenum"><a name="Page_120" id="Page_120">[120]</a></span>
+which corresponds to the first molar tooth, to terminate,
+after a course more or less prolonged, at the alveolus
+of the canine. This space, more or less considerably expanded,
+which thus separates these teeth is called the <i>interdental
+space</i>; but this denomination is not applicable to
+ruminants, because these latter possess neither canine nor
+incisor teeth in the upper jaw (see <a href="#Page_125">p. 125</a>, dentition of the
+ox and sheep). The superior maxillary bone of one side and
+that of the opposite side do not meet in the median line in the
+region which corresponds to the incisor teeth; they are separated
+by a bone which, in the human species, is present only
+at the commencement of life, and afterwards coalesces with
+the maxilla; this is the intermaxillary or incisor bone.
+This bone, which is paired, is formed of a central part, which
+bears the superior incisor teeth; it is prolonged upwards
+and backwards by two processes: one, external, which insinuates
+itself between the superior maxillary and the nasal
+bone, except in the sheep, in which it remains widely separated
+from the latter; the other, internal, which is united to
+that which belongs to the bone of the opposite side to form
+part of the floor of the cavity of the nasal foss&aelig;; the external
+border of this process, which is separated from the body of the
+bone by a notch, forms the internal boundary of the corresponding
+<i>incisor opening</i> or the <i>incisor slit</i>. Owing to the
+absence of superior incisors in ruminants, the intermaxillary
+bone presents no alveoli.</p>
+
+<p>The malar bone, and the os unguis or lachrymal, are
+more or less developed according to the species considered.
+With regard to the malar bone, it is most important to
+notice the part which it takes in the formation of the
+zygomatic arch, and that its inferior border contributes
+to form the crest to which is attached the masseter
+muscle.</p>
+
+<p>As for the nasal bones, they present differential characters
+which, as they affect the form of the region which they
+occupy, are worthy of notice.</p>
+
+<div class="figmed"><a name="Fig063" id="Fig063"></a>
+<img src="images/illo144.png" alt="Fig. 63" width="450" height="420" />
+<p class="caption">Fig. 63.&mdash;Skull of the Horse: Left Lateral Aspect.</p>
+
+<p class="subcaption just">1, Posterior surface of the occipital bone; 2, external occipital protuberance;
+3, occipital condyle; 4, jugular process; 5, parietal bone;
+6, frontal bone; 7, orbital cavity; 8, zygomatic process of the temporal
+bone; 9, external auditory canal; 10, mastoid process; 11, superior
+maxillary bone or <i>maxilla</i>; 12, intermaxillary or incisor bone; 13, nasal
+bone; 14, malar bone; 15, lachrymal bone; 16, inferior maxillary
+bone or <i>mandible</i>; 17, inferior maxillary fissure; 18, condyle of the inferior
+maxillary bone; 19, coronoid process of the inferior maxillary bone;
+20, incisor teeth; 21, canine teeth; 22, molar teeth.</p></div>
+
+<p>Their dimensions in length are proportional to those of
+the face. Very small in man, they are more developed
+in carnivora. We recognise in the latter the two curves<span class="pagenum"><a name="Page_121" id="Page_121">[121]</a></span>
+which characterize them in the human species, and which
+we clearly notice when we view them on one of their
+lateral aspects: a concavity above, and a convexity below.
+These curves are more or less accentuated&mdash;very strongly
+marked in the bulldog, and scarcely at all in the greyhound.
+Moreover, in the carnivora also the nasal bones are wider
+below than above, and form, by their junction, a semicircular
+notch which limits, in its superior portion, the
+anterior opening of the cavity of the nasal foss&aelig;. In the
+horse they present an opposite arrangement with regard to
+their dimensions in width; broad above, each terminates<span class="pagenum"><a name="Page_122" id="Page_122">[122]</a></span>
+below by forming a pointed process which, separated from the
+intermaxillary bones, is prolonged in front of the nasal orifice.</p>
+
+<p>The inferior maxillary bone is, as in man, formed of a
+body and two branches. But among the many special
+characteristics of form and size which sharply differentiate
+it from the human bone, one detail must be
+indicated; this is the absence of a mental prominence.
+Hence it results that the anterior border of the body of the
+lower jaw, instead of being directed obliquely downwards
+and forwards, is, on the contrary, oblique downwards
+and backwards, and that in certain animals this border is
+actually found almost exactly on the prolongation of the
+inferior border of the body of the bone.</p>
+
+<p>On the external surface of the body are found the three
+mental foramina. The superior border is hollowed out by
+alveoli.</p>
+
+<p>With regard to the branches (<i>rami</i>), they terminate in two
+processes: one, the posterior, is the condyle; the other,
+situated more forwards, is the coronoid process, which gives
+insertion to the temporal muscle. These two processes are
+separated by the sigmoid notch.</p>
+
+<div class="figmed"><a name="Fig064" id="Fig064"></a>
+<img src="images/illo146.png" alt="Fig. 64" width="450" height="295" />
+<p class="caption just">Fig. 64.&mdash;Skull of the Hare: Left Lateral Aspect.</p>
+
+<p class="subcaption just">1, External occipital protuberance; 2, occipital condyle; 3, parietal
+bone; 4, frontal bone; 5, orbital process; 6, orbital cavity; 7, zygomatic
+process; 8, external auditory canal; 9, superior maxillary bone;
+10, intermaxillary or incisor bone; 11, nasal bone; 12, anterior opening
+of the nasal fossa; 13, malar bone; 14, inferior maxillary bone; 15,
+condyle of the inferior maxillary bone; 16, incisor teeth; 17, molar
+teeth.</p></div>
+
+<p>For reasons which we will explain further on (see <a href="#Page_127">p. 127</a>,
+movements of the lower jaw), the condyle presents differences
+of form. In the carnivora, it is strongly convex from
+before backwards, expanded transversely, and firmly mortised
+in the glenoid cavity of the temporal bone; in the
+ruminants, it is less convex from before backwards, it is
+more slightly concave in the transverse direction; in the
+rodents&mdash;we give as an example the hare (<a href="#Fig064">Fig. 64</a>)&mdash;the
+condyle is still convex from before backwards, but it is
+flattened from without inwards.</p>
+
+<p>In the animals in which the muscles of mastication are
+very highly developed, and especially in the carnivora, the
+osseous regions occupied by these muscles are more extensive
+and more deep than in the human species. The length of
+the coronoid process, the depth of the temporal fossa, the
+extent of the zygomatic arch, the appearance of the external
+surface of each of the rami of the lower jaw, deeply hollowed
+out for accommodation of the masseter, and to provide extensive<span class="pagenum"><a name="Page_123" id="Page_123">[123]</a></span>
+surfaces of insertion for this muscle, are sure proofs
+furnished by the skeleton of the occasionally enormous development
+of the muscles of mastication.</p>
+
+<p>In the carnivora, a rather strong process, which is directed
+backwards, occupies the angle of the inferior maxilla; it is,
+accordingly, situated below the region of the condyle.</p>
+
+<p>The teeth which the jaws carry vary in number, and even
+in appearance, according to species; it is useful to note their
+differences. In order to establish the nature of these latter
+more effectively, we will first recall the fact that in man the
+teeth, thirty-two in number, are equally distributed between
+the jaws, and are divided into incisors, canines, and molars,
+of which the arrangement is thus formulated:</p>
+
+<table summary="Table page 123">
+
+<tr>
+<td class="center bb padl2 padr2">5<i>m.</i></td>
+<td class="center bb padl2 padr2">1<i>c.</i></td>
+<td class="center bb br padl2 padr2">2<i>i.</i></td>
+<td class="center bb padl2 padr2">2<i>i.</i></td>
+<td class="center bb padl2 padr2">1<i>c.</i></td>
+<td class="center bb padl2 padr2">5<i>m.</i></td>
+<td rowspan="2" class="left">&nbsp;=&nbsp;32.<a name="FNanchor_19_19"
+id="FNanchor_19_19"></a><a href="#Footnote_19_19" class="fnanchor">[19]</a></td>
+</tr>
+
+<tr>
+<td class="center padl2 padr2">5<i>m.</i></td>
+<td class="center padl2 padr2">1<i>c.</i></td>
+<td class="center br padl2 padr2">2<i>i.</i></td>
+<td class="center padl2 padr2">2<i>i.</i></td>
+<td class="center padl2 padr2">1<i>c.</i></td>
+<td class="center padl2 padr2">5<i>m.</i></td>
+</tr>
+
+</table>
+
+<div class="footnote"><p><a name="Footnote_19_19" id="Footnote_19_19"></a><a href="#FNanchor_19_19"><span
+class="label">[19]</span></a> <i>I.e.</i>, <i>i</i>, incisors; <i>c</i>, canines; <i>m</i>, molars.</p></div>
+
+<p><span class="pagenum"><a name="Page_124" id="Page_124">[124]</a></span>We also note that the incisors are edged, the canines are
+pointed, and that the molars, cubical in shape, have their
+surface of contact provided with tubercles.</p>
+
+<p>The teeth of the cat are thirty in number; they are thus
+arranged:</p>
+
+<table summary="Table page 124-1">
+
+<tr>
+<td class="center bb padl2 padr2">4<i>m.</i></td>
+<td class="center bb padl2 padr2">1<i>c.</i></td>
+<td class="center bb br padl2 padr2">3<i>i.</i></td>
+<td class="center bb padl2 padr2">3<i>i.</i></td>
+<td class="center bb padl2 padr2">1<i>c.</i></td>
+<td class="center bb padl2 padr2">4<i>m.</i></td>
+<td rowspan="2" class="left">&nbsp;=&nbsp;30.</td>
+</tr>
+
+<tr>
+<td class="center padl2 padr2">3<i>m.</i></td>
+<td class="center padl2 padr2">1<i>c.</i></td>
+<td class="center br padl2 padr2">3<i>i.</i></td>
+<td class="center padl2 padr2">3<i>i.</i></td>
+<td class="center padl2 padr2">1<i>c.</i></td>
+<td class="center padl2 padr2">3<i>m.</i></td>
+</tr>
+
+</table>
+
+<p>Those of the dog number forty-two:</p>
+
+<table summary="Table page 124-2">
+
+<tr>
+<td class="center bb padl2 padr2">6<i>m.</i></td>
+<td class="center bb padl2 padr2">1<i>c.</i></td>
+<td class="center bb br padl2 padr2">3<i>i.</i></td>
+<td class="center bb padl2 padr2">3<i>i.</i></td>
+<td class="center bb padl2 padr2">1<i>c.</i></td>
+<td class="center bb padl2 padr2">6<i>m.</i></td>
+<td rowspan="2" class="left">&nbsp;=&nbsp;42.</td>
+</tr>
+
+<tr>
+<td class="center padl2 padr2">7<i>m.</i></td>
+<td class="center padl2 padr2">1<i>c.</i></td>
+<td class="center br padl2 padr2">3<i>i.</i></td>
+<td class="center padl2 padr2">3<i>i.</i></td>
+<td class="center padl2 padr2">1<i>c.</i></td>
+<td class="center padl2 padr2">7<i>m.</i></td>
+</tr>
+
+</table>
+
+<p>In these animals, the incisors, such as are not damaged by
+use, are furnished, on the free border of their crown, with
+three tubercles, of which one, the median, is more developed
+than those which are situated laterally. We denote these teeth,
+commencing with those nearest the median line, by the names
+<i>central incisors</i> or <i>nippers</i>, <i>intermediate</i> and <i>corner incisors</i>.
+The canines, or <i>fangs</i>, are long and conical; they are curved
+backwards and outwards. The upper canines, which are
+larger than those of the lower jaw, are separated from the most
+external of the incisors (<i>corner</i>) by an interval in which the
+canines of the lower jaw are received. The lower canines, on
+the other hand, are in contact with the neighbouring incisors,
+and are each separated from the first molar which succeeds
+them by a wider interval than that which is situated between
+the corresponding teeth in the upper jaw.</p>
+
+<p>The molars differ essentially from the teeth of the same
+class in the human species. Their crown terminates in a
+cutting border bristling with sharp-pointed projections; this
+formation indicates that these teeth are principally designed
+for tearing. During the movement of raising the lower jaw,
+which is so energetic in the carnivora, they act, indeed, in
+the same manner as the two blades of a pair of scissors. The
+largest molars are: in the dog, the fourth of the upper jaw,
+and the fifth in the opposite one; in the cat, the third both
+above and below.</p>
+
+<p><span class="pagenum"><a name="Page_125" id="Page_125">[125]</a></span>The pig has forty-four teeth disposed in the following
+manner:</p>
+
+<table summary="Table page 125-1">
+
+<tr>
+<td class="center bb padl2 padr2">7<i>m.</i></td>
+<td class="center bb padl2 padr2">1<i>c.</i></td>
+<td class="center bb br padl2 padr2">3<i>i.</i></td>
+<td class="center bb padl2 padr2">3<i>i.</i></td>
+<td class="center bb padl2 padr2">1<i>c.</i></td>
+<td class="center bb padl2 padr2">7<i>m.</i></td>
+<td rowspan="2" class="left">&nbsp;=&nbsp;44.</td>
+</tr>
+
+<tr>
+<td class="center padl2 padr2">7<i>m.</i></td>
+<td class="center padl2 padr2">1<i>c.</i></td>
+<td class="center br padl2 padr2">3<i>i.</i></td>
+<td class="center padl2 padr2">3<i>i.</i></td>
+<td class="center padl2 padr2">1<i>c.</i></td>
+<td class="center padl2 padr2">7<i>m.</i></td>
+</tr>
+
+</table>
+
+<p>Of the incisors, the nippers and the intermediate ones of the
+upper jaw have their analogues in those of the horse; in the
+lower jaw, the corresponding teeth, straight, and directed forward,
+rather resemble the same incisors in rodents. The
+corner incisor teeth are much smaller, and are separated from
+the neighbouring teeth. The canine teeth, also called <i>tusks</i>
+or <i>tushes</i>, are greatly developed, especially in the male. The
+molars increase in size from the first to the last; they are not
+cutting, as in the carnivora, but they are not flattened and
+provided with tubercles on their surfaces of contact as in the
+herbivora.</p>
+
+<p>In the ox and the sheep the teeth are thirty-two in
+number:</p>
+
+<table summary="Table page 125-2">
+
+<tr>
+<td class="center bb padl2 padr2">6<i>m.</i></td>
+<td class="center bb padl2 padr2">0<i>c.</i></td>
+<td class="center bb br padl2 padr2">0<i>i.</i></td>
+<td class="center bb padl2 padr2">0<i>i.</i></td>
+<td class="center bb padl2 padr2">0<i>c.</i></td>
+<td class="center bb padl2 padr2">6<i>m.</i></td>
+<td rowspan="2" class="left">&nbsp;=&nbsp;32.</td>
+</tr>
+
+<tr>
+<td class="center padl2 padr2">6<i>m.</i></td>
+<td class="center padl2 padr2">0<i>c.</i></td>
+<td class="center br padl2 padr2">4<i>i.</i></td>
+<td class="center padl2 padr2">4<i>i.</i></td>
+<td class="center padl2 padr2">0<i>c.</i></td>
+<td class="center padl2 padr2">6<i>m.</i></td>
+</tr>
+
+</table>
+
+<p>As we see from this dental formula, the incisors are found
+only in the lower jaw; they are replaced in the upper jaw
+by a thick cartilaginous pad on which the inferior incisors
+find a surface of resistance.</p>
+
+<p>These have their crowns flattened from above downwards,
+and gradually become thinner from the root to the anterior
+border, which is edged and slightly convex. These teeth
+gradually wear away. In proportion to the progress of this
+wear, on account of the fact that it involves the anterior
+borders and upper surfaces of the incisor teeth, and that
+these teeth are narrower towards the root than at the opposite
+extremity, the intervals which separate them tend to
+become wider and wider; and when the roots become exposed
+by the retraction of the gums, they are then separated
+from one another by a considerable interval. The molars
+have their grinding surface comparable to that of the horse;
+they increase in size from the first to the sixth.</p>
+
+<p><span class="pagenum"><a name="Page_126" id="Page_126">[126]</a></span>The teeth of the horse are forty in number; they are
+thus distributed:</p>
+
+<table summary="Table page 126-1">
+
+<tr>
+<td class="center bb padl2 padr2">6<i>m.</i></td>
+<td class="center bb padl2 padr2">1<i>c.</i></td>
+<td class="center bb br padl2 padr2">3<i>i.</i></td>
+<td class="center bb padl2 padr2">3<i>i.</i></td>
+<td class="center bb padl2 padr2">1<i>c.</i></td>
+<td class="center bb padl2 padr2">6<i>m.</i></td>
+<td rowspan="2" class="left">&nbsp;=&nbsp;40.</td>
+</tr>
+
+<tr>
+<td class="center padl2 padr2">6<i>m.</i></td>
+<td class="center padl2 padr2">1<i>c.</i></td>
+<td class="center br padl2 padr2">3<i>i.</i></td>
+<td class="center padl2 padr2">3<i>i.</i></td>
+<td class="center padl2 padr2">1<i>c.</i></td>
+<td class="center padl2 padr2">6<i>m.</i></td>
+</tr>
+
+</table>
+
+<p>As they become worn, these teeth continue to grow, and as,
+on the one hand, this phenomenon takes place throughout
+the whole life of the animal, and, on the other hand, the
+process of wear brings out and makes visible at the surface
+of friction parts formerly deeper and deeper, and of which
+the configuration varies at different levels, there result
+special features which permit the determination of the age of
+the animal by an examination of its jaws. The incisors are
+called, commencing with those situated nearest the middle
+line, <i>central incisors</i> or <i>nippers</i>, <i>intermediate</i> and <i>corner incisors</i>.
+The canines, also designated as the <i>fangs</i>, exist only
+in the male. It is exceptional to find them in the mare, and
+when they exist in this latter they are less developed than
+those of the horse. The molars have cuboid crowns; the
+surface of friction is almost square in the case of the upper
+molars, and is inclined so as to look inwards; in the case of
+the inferior ones, it is a little narrowed, and is inclined so
+as to look outwards. In the upper jaw the external surface
+of the crown is hollowed by two longitudinal furrows;
+in the lower jaw the same surface has only one furrow,
+which at times is but slightly marked.</p>
+
+<p>In the hare the teeth are twenty-eight in number:</p>
+
+<table summary="Table page 126-2">
+
+<tr>
+<td class="center bb padl2 padr2">6<i>m.</i></td>
+<td class="center bb padl2 padr2">0<i>c.</i></td>
+<td class="center bb br padl2 padr2">2<i>i.</i></td>
+<td class="center bb padl2 padr2">2<i>i.</i></td>
+<td class="center bb padl2 padr2">0<i>c.</i></td>
+<td class="center bb padl2 padr2">6<i>m.</i></td>
+<td rowspan="2" class="left">&nbsp;=&nbsp;28.</td>
+</tr>
+
+<tr>
+<td class="center padl2 padr2">5<i>m.</i></td>
+<td class="center padl2 padr2">0<i>c.</i></td>
+<td class="center br padl2 padr2">1<i>i.</i></td>
+<td class="center padl2 padr2">1<i>i.</i></td>
+<td class="center padl2 padr2">0<i>c.</i></td>
+<td class="center padl2 padr2">5<i>m.</i></td>
+</tr>
+
+</table>
+
+<p>The four incisors of the upper jaw are divided into two
+groups; one of these is formed by the two principal teeth,
+the other by two very small incisors which are placed behind
+the preceding.</p>
+
+<p>Having studied the jaws and examined the arrangement
+of the teeth, we should say a few words on the movements
+which the lower jaw is able to execute. In
+man, these movements are varied in character: the jaw
+is lowered and raised; it can also be projected forwards<span class="pagenum"><a name="Page_127" id="Page_127">[127]</a></span>
+and drawn backwards, or carried to the right or left side
+by lateral movements. Owing to the different modes of
+nutrition of animals, with which the shape of the teeth
+is clearly correlated, being more specialized than in the
+human species, the lower jaw is moved in a fashion less
+varied and in the direction most suitable for the mastication
+of the foods which form the aliment of the species considered.
+Moreover, this is plainly shown in the skeleton by the shape
+of the condyle of the lower jaw (see <a href="#Page_122">p. 122</a>, different forms of
+this condyle). In the carnivora, whose teeth, as we have
+seen, are all cutting ones, the jaw rises and falls; the food
+then is, if we consider the two jaws, cut as by the blades
+of a pair of scissors. In the ruminants, the incisors exist
+only in the lower jaw, but the molars are thick and well
+developed; the food is ground by these latter as by millstones,
+and the movements which favour this action are,
+above all, the lateral. As for the rodents, in which the
+incisors are formed for filing down and cutting through hard
+resisting bodies, their lower jaw moves in the antero-posterior
+direction, in such a way that the inferior incisors alternately
+advance and recede beneath those of the upper jaw. The
+free cutting border of these teeth effectively fulfils the function
+to which they are destined; their constant wear preserves
+and revivifies the chisel edge which characterizes
+them, without leading to their destruction, for the incisors
+in rodents are of continuous growth.</p>
+
+<h3>THE SKULL OF BIRDS</h3>
+
+<p><b>The Skull of Birds</b> (<a href="#Fig065">Fig. 65</a>).&mdash;If, because it is less
+important from the artistic point of view, we do not consider
+it necessary to describe in detail the skull of birds,
+we yet think it useful to indicate, in their general lines, the
+peculiarities it presents.</p>
+
+<div class="figmed"><a name="Fig065" id="Fig065"></a>
+<img src="images/illo151.png" alt="Fig. 65" width="400" height="220" />
+<p class="caption just">Fig. 65.&mdash;Skull of the Cock: Left Lateral Surface.</p>
+
+<p class="subcaption just">1, Occipital bone; 2, parietal bone; 3, frontal bone; 4, ethmoid bone;
+5, cavity of the tympanum; 6, quadrate bone; 7, superior maxillary
+bone; 8, malar bone; 9, nasal bone; 10, 10, intermaxillary bone; 11,
+nasal orifice; 12, os unguis or lachrymal bone; 13, inferior maxillary bone.</p></div>
+
+<p>In this group the skull is generally pear-shaped; to the
+cranium, of which the bones are arranged in such a way
+as to give it a form more or less spherical, succeeds a face
+more or less elongated, according as the bill is more or less
+developed.</p>
+
+<p>In general, the bones of the skull coalesce very early, with<span class="pagenum"><a name="Page_128" id="Page_128">[128]</a></span>
+the result that it is only in very young individuals that we
+can determine their presence.</p>
+
+<p>We find the skull to consist of an occipital bone, two
+parietals, a frontal, etc.; we will indicate but one detail in
+connection with these bones: it is the presence of a single
+condyle for the articulation of the occipital bone with the
+atlas. We also note the quadrate bone, which is situated on
+the lateral part of the cranium, is movable on this latter,
+and acts as an intermediary between it, the bones of the face,
+and the lower jaw. The quadrate bone is regarded as a
+detached portion of the temporal; on the signification of
+this we do not now propose to dwell.</p>
+
+<p>On the anterior portion of the face we find the nasal bones,
+which, articulating with the frontal on one side, circumscribe,
+on the other, the posterior border of the nares. The nasal
+bone of the one side is separated from that of the opposite by
+the intermaxillary or premaxillary bone, which forms the
+skeleton of the superior mandible.</p>
+
+<p>The superior maxillaries, which are rudimentary, are
+situated on the lateral parts, and prolonged backward by an
+osseous style which articulates with the quadrate bone;
+this styloid bone, the homologue of the malar, is designated
+by certain authors as the <i>jugal</i> or <i>quadrato-jugal</i> bone.</p>
+
+<p>It is with the quadrate bone also that the inferior
+maxillary articulates.</p>
+
+<hr class="c25" />
+<p class="pagenum"><a name="Page_129" id="Page_129">[129]</a></p>
+<h2>CHAPTER II</h2>
+
+<h3>MYOLOGY</h3>
+
+<p>The first point to decide in commencing this study is the
+order in which we shall consider the different muscles which
+we have to examine. It must not be forgotten that in the
+present work we compare the organization of animals with
+that of man, which we already know, and that it is on the
+construction of this latter that, in these studies, the thought
+must at each instant be carried back in order to establish
+this comparison. Now, the general tendency which we
+notice in our teaching of anatomy, when one regards the
+region of the trunk in the human figure (a living model or
+a figure in the round), is first to consider the anterior aspect.
+It is the latter that, for this reason, we study at the very
+beginning; we next deal with the posterior surface of the
+trunk, because it is opposite; lastly, the lateral surfaces,
+because they unite with the preceding surfaces, the one to
+the other.</p>
+
+<p>In studying an animal, it is usually by one of its lateral
+aspects that one first observes it; it is, in fact, by these
+aspects that it presents its greatest dimensions, and that the
+morphological characters as a whole can be more readily
+appreciated. Hence, possibly, the order of description
+adopted in most texts, or in the figures which accompany
+them. The first representation of the human figure as a
+whole, in a treatise on anatomy, represents the anterior
+aspect; the first view of the horse as a whole, in a treatise
+on veterinary anatomy, for example, is, on the other hand,
+a lateral view.</p>
+
+<p><span class="pagenum"><a name="Page_130" id="Page_130">[130]</a></span>We break with this latter custom, and, without taking into
+account the tendency above indicated, we will commence
+our analysis with the study of the aspect of the trunk,
+which corresponds to the anterior aspect of the same region
+in man.</p>
+
+<p>The first muscles usually presented for study to artists
+being the pectorals, it is their <a href="#Pectorals">homologues</a> that we will first
+describe here. We will afterwards describe the <a href="#Abdominals">abdominal
+region</a>, then the muscles which occupy the <a href="#Dorsals">dorsal aspect</a>
+of the trunk. With regard to the lateral surfaces, they will
+be found, by this fact alone, almost completely studied,
+since the muscles of the two preceding (back and abdomen),
+spreading out, so to speak, over them, contribute to their
+formation. Nothing further will remain but to incorporate
+with them the <a href="#Shoulders">muscles of the shoulder</a>; but these will be
+studied in connection with the anterior limbs, from which
+they cannot be separated.</p>
+
+<p>The neck, in man, may be considered in an isolated fashion,
+because, on account of its narrowness in proportion to the
+width of the shoulders, it is clearly differentiated from the
+trunk; for this reason we combine the study of it with
+that of the head. In animals, because of the absence or
+slight development of the clavicles, the neck is generally
+too much confounded with the region of the shoulders to
+make it legitimate to separate it from that region in too
+marked a fashion. It will, accordingly, be considered <a href="#NeckMuscles">next</a>.</p>
+
+<p>We will then undertake the study of the <a href="#LimbMuscles">muscles of the
+limbs</a>, and end with the <a href="#HeadMuscles">myology of the head</a>.</p>
+
+<p class="pagenum"><a name="Page_131" id="Page_131">[131]</a></p>
+<h4>THE MUSCLES OF THE TRUNK</h4>
+
+<p>We shall divide them into muscles of the thorax, of the
+abdomen, and of the back.</p>
+
+<h5><a name="Pectorals" id="Pectorals"></a>Muscles of the Thorax</h5>
+
+<p><b>The Pectoralis Major</b> (<a href="#Fig066">Fig. 66</a>, 1, 2; <a href="#Fig067">Fig. 67</a>, 3, 4;
+<a href="#Fig068">Fig. 68</a>, 7; <a href="#Fig069">Fig. 69</a>, 10; <a href="#Fig070">Fig. 70</a>, 11).&mdash;Further designated
+by the name of <i>superficial pectoral</i>, this muscle is described
+in treatises on veterinary anatomy as formed of two portions:
+an anterior one, called the <i>sterno-humeral</i> muscle;
+the other, situated below and behind the preceding, bearing
+the name of <i>sterno-aponeurotic</i>.</p>
+
+<p>It occupies the region of the breast, and, as a whole, it
+takes origin from the median portion of the sternum, from
+which it is directed towards the arm and forearm.</p>
+
+<p>The anterior portion (sterno-humeral muscle)&mdash;thick,
+forming an elevation under the skin, and really constituting
+the pectoral region&mdash;is directed downwards and outwards
+to be inserted into the anterior margin of the humerus&mdash;that
+is to say, to the ridge which limits in front the spiral
+groove of this bone.</p>
+
+<p>The other part (sterno-aponeurotic muscle) is situated
+more posteriorly, and corresponds to the region known in
+veterinary anatomy as the <i>inter-fore-limb space</i>, which is
+limited laterally on each side by the superior portion of
+the forearm, of which the point of junction with the trunk
+bears the name <i>ars</i>. Arising from the sternum, as we
+have above indicated, this portion is directed outwards,
+to be joined with the terminal aponeurosis of the sterno-humeral,
+and with that which covers the internal surface
+of the forearm.</p>
+
+<p>All things considered, the sterno-humeral muscle may be
+regarded as the representative of the upper fibres of the
+great pectoral of man, of which the attachments, owing to
+the more or less complete absence of the clavicle in the
+domestic mammals, the fibres must be concentrated on the<span class="pagenum"><a name="Page_132" id="Page_132">[132]</a></span>
+sternum; the sterno-aponeurotic portion then representing
+the inferior fascicul&aelig; of the same muscle.</p>
+
+<div class="figmed"><a name="Fig066" id="Fig066"></a>
+<img src="images/illo155.png" alt="Fig. 66" width="350" height="364" />
+<p class="caption just">Fig. 66.&mdash;Myology of the Horse: Anterior Aspect of the Trunk.</p>
+
+<p class="subcaption just">1, Pectoralis major (sterno-humeral); 2, pectoralis major (sterno-aponeurotic);
+3, mastoido-humeralis; 4, point of the shoulder; 5, sterno-mastoid
+or sterno-maxillary: 6, inferior portion of the platysma myoides
+of the neck, divided; 7, triceps cubiti; 8, brachialis anticus; 9, radialis
+(anterior extensor of the metacarpus); 10, scapular region.</p></div>
+
+<p>The great pectoral muscle of one side is separated from
+that of the opposite side along the median line, and especially
+above and in front, by a groove which is more or less
+deep, according as the muscles are more or less developed.
+At the bottom of this groove, suggestive of that which
+exists in the corresponding region in man, is found, as in
+this latter, the median portion of the sternum.</p>
+
+<p>The preceding description particularly applies to the
+arrangement which the great pectoral presents in the horse;
+in other animals it is marked by some distinctive characters.
+In the pig, it is inserted into the sternum as far only as the
+level of the third costal cartilage; in the ox and sheep, it<span class="pagenum"><a name="Page_133" id="Page_133">[133]</a></span>
+extends as far as the sixth; in the dog, it is attached to the
+two first sternal pieces only&mdash;that is to say, as far as the
+third costal cartilage. Moreover, in the latter, as in the
+cat, the two portions which we have indicated are less
+readily distinguished.</p>
+
+<p>The great pectoral, by its contraction, draws the
+fore-limb towards the middle line&mdash;that is to say, adducts
+it.</p>
+
+<p><b>The Pectoralis Minor</b> (<a href="#Fig067">Fig. 67</a>, 6; <a href="#Fig068">Fig. 68</a>, 8; <a href="#Fig069">Fig. 69</a>,
+11; <a href="#Fig070">Fig. 70</a>, 12, 26).&mdash;This muscle, also called the <i>deep
+pectoral</i>, is, in animals, larger than the superficial pectoral,
+therefore certain authors prefer to give to this muscle and
+the preceding one the names of deep and superficial pectoral
+respectively. This nomenclature is evidently legitimate,
+and conforms more to reality, since it does not bring in
+the notion of dimensions which here is found in contradiction
+to nomenclature; but, in order to establish more
+clearly the parallelism with the corresponding muscles in
+man, we think it better, nevertheless, to give them the
+names by which it has been customary to designate them
+in connection with the latter.</p>
+
+<p>We will recall at the outset that the lesser pectoral
+muscle in man is completely covered by the great. In
+animals this is not the case; the lesser pectoral being
+very highly developed, projects beyond the great pectoral
+posteriorly, and occupies to a greater or less extent the
+inferior surface of the abdomen.</p>
+
+<p>It also consists of two parts: one anterior, which we
+designate by the name of <i>sterno-prescapular</i>; the other,
+posterior, bearing that of <i>sterno-humeral</i>.<a name="FNanchor_20_20" id="FNanchor_20_20"></a><a href="#Footnote_20_20"
+class="fnanchor">[20]</a></p>
+
+<div class="footnote"><p><a name="Footnote_20_20" id="Footnote_20_20"></a><a href="#FNanchor_20_20"><span class="label">[20]</span></a>
+This division of the pectorals certainly complicates the nomenclature
+of these muscles; nevertheless, it introduces no insuperable difficulty
+from the mnemonic point of view. But where the study becomes less
+profitable, and comparison with the corresponding muscles in man
+more complicated, is in adopting the nomenclature of Bourgelat.
+Indeed, the great pectoral is designated by this author the &#8216;common
+muscle of the arm and forearm,&#8217; while the lesser pectoral (or deep
+pectoral) is called the &#8216;great pectoral&#8217; in its sterno-trochinian and
+&#8216;lesser pectoral&#8217; in its sterno-prescapular portion. We do not consider
+it necessary to give the other theories relative to the homologies of these,
+notwithstanding the very real interest which they present from the
+purely anatomical point of view, as they have but few applications in the
+study of forms.</p></div>
+
+<p>The sterno-prescapular muscle, being covered by the
+sterno-humeral, has little interest for us. It arises from<span class="pagenum"><a name="Page_134" id="Page_134">[134]</a></span>
+the sternum, and is directed towards the angle formed by
+the junction of the scapula and humerus; then it is reflected
+upwards and backwards, to terminate on the
+anterior margin of the shoulder by insertion into the
+aponeurosis, which covers the supraspinatus muscle.</p>
+
+<p>We can, especially in the horse after removal of the skin,
+recognise it, at the level of this region, in the interspace
+limited by the superficial muscles (<a href="#Fig070">Fig. 70</a>, 26).</p>
+
+<p>In the dog and cat this portion of the muscle does
+not exist. The other division of the muscle, the sterno-trochinian,
+is more interesting. It arises from the abdominal
+aponeurosis and the posterior part of the sternum;
+hence it passes forward, turns under the superficial pectoral,
+and is inserted into the lesser tuberosity (trochin) of the
+humerus.</p>
+
+<p>In the pig, dog, and cat, it is inserted into the greater
+tuberosity (trochiter) of the bone of the arm.</p>
+
+<p>The superior border of this muscle is in relation with
+a superficial vein, which is distinctly visible in the horse&mdash;the
+subcutaneous thoracic vein, which in this animal is
+called the vein of the spur.</p>
+
+<p>The sterno-humeral muscle, in contracting, draws the
+shoulder and the whole anterior limb backwards.</p>
+
+<p><b>Serratus Magnus</b> (<a href="#Fig067">Fig. 67</a>, 2;
+<a href="#Fig069">Fig. 69</a>, 8; <a href="#Fig070">Fig. 70</a>, 9).&mdash;This
+muscle, which is situated on the lateral aspect of
+the thorax, is covered to a considerable extent by the
+shoulder, the posterior muscular mass of the arm, and by
+the great dorsal muscle.</p>
+
+<p>It arises by digitations from the external surface of the
+dorsal vertebr&aelig;; from the first eight in the horse, ox, and
+dog.</p>
+
+<p class="pagenum"><a name="Page_135" id="Page_135">[135]</a></p>
+
+<div class="figmed"><a name="Fig067" id="Fig067"></a>
+<img src="images/illo158.png" alt="Fig. 67" width="300" height="460" />
+<p class="caption just">Fig. 67.&mdash;Myology of the Horse: Inferior Aspect of the Trunk.</p>
+
+<p class="subcaption just">1, Anterior extremity of the sternum; 2, point of the shoulder and
+inferior portion of the mastoido-humeral muscle; 3, pectoralis major
+(sterno-humeral); 4, pectoralis major (sterno-aponeurotic); 5, point of
+the elbow; 6, pectoralis minor (sterno-trochinian); 7, serratus magnus;
+8, external oblique; 9, sheath of the rectus abdominis; 10, linea alba;
+11, the umbilicus; 12, external oblique divided in order to expose the
+rectus abdominis; 13, rectus abdominis.</p></div>
+
+<p>The muscular bundles, converging as they proceed, towards
+the scapula, pass under this bone, to be inserted
+into the superior portion of the subscapular fossa, near<span class="pagenum"><a name="Page_136" id="Page_136">[136]</a></span>
+the spinal border. The inferior portion of its posterior
+digitations is visible in the ox and in the horse; these
+digitations are less visible in the pig. They are not seen
+at all in the dog (<a href="#Fig068">Fig. 68</a>) or cat, for in these animals the
+great dorsal muscle covers them completely.</p>
+
+<p>The great serratus muscle, by the position which it
+occupies and the arrangement that it presents, forms with
+the corresponding muscle of the opposite side a sort of
+girth, which supports the thorax, and at the same time
+helps to fix the scapula against the latter.</p>
+
+<p>When it contracts, in taking its fixed point at the ribs,
+it draws the superior portion of the scapula downwards and
+backwards in such a way that this bone has its inferior
+angle directed forwards and upwards. If it takes its fixed
+point at the shoulder, it then acts on the ribs, raises them,
+and so becomes a muscle of inspiration.</p>
+
+<p>Because of the connections of the serratus magnus with the
+levator anguli scapul&aelig;, some authors consider it as united
+with the latter. But as the latter muscle is visible only
+in the region of the neck (see <a href="#Page_157">p. 157</a>), and as it is separately
+described in man, we prefer to distinguish them from one
+another. We shall recall the connections to which we
+have just made allusion when describing the cervical
+region.</p>
+
+<h5><a name="Abdominals" id="Abdominals"></a>Muscles of the Abdomen</h5>
+
+<p>The abdominal wall is, as in man, formed by four large
+muscles: the external oblique, the internal oblique, and
+the transversalis, which form the lateral walls, and the
+rectus abdominis, situated on each side of the middle
+line of the abdomen. This latter, because of the general
+direction of the trunk in quadrupeds, has its superficial
+surface directed downwards.</p>
+
+<p>The arrangement of these muscles closely corresponds to
+that which we find in the human species.</p>
+
+<p><b>The External Oblique Muscle</b> (<a href="#Fig067">Fig. 67</a>, 8, 12; <a href="#Fig068">Fig. 68</a>, 5;
+<a href="#Fig069">Fig. 69</a>, 9; <a href="#Fig070">Fig. 70</a>, 10).&mdash;This muscle arises, by digitations,
+from a number of ribs, which varies according to the species,
+the number of the ribs being itself variable for each of them,<span class="pagenum"><a name="Page_137" id="Page_137">[137]</a></span>
+as we pointed out in connection with the osteology of the
+thorax. Indeed, the great oblique arises from the eight or
+nine posterior ribs in the dog and the ox, and from the
+thirteen or fourteen posterior in the horse. It is attached,
+besides, to the dorso-lumbar aponeurosis.</p>
+
+<p>These attachments are arranged in a line directed obliquely
+upwards and backwards, and the first digitations&mdash;that is
+to say, the most anterior ones&mdash;dovetail with the posterior
+digitations of origin of the great serratus muscle.</p>
+
+<p>The fleshy fibres are directed downwards and backwards,
+and terminate in an aponeurosis which covers the inferior
+aspect of the abdomen, and proceeds to form the linea alba
+by joining with that of the muscle of the opposite side,
+and also to be inserted into the crural arch.</p>
+
+<p>This aponeurosis of the external oblique is covered by
+an expansion of elastic fibrous tissue, which doubles it externally,
+and which is known as the <i>abdominal tunic</i>. This
+latter is further developed as the organs of the digestive
+apparatus are more voluminous, and their weight, consequently,
+more considerable. For this reason, in the
+large herbivora, as the ox and the horse, this tunic is extremely
+thick, whereas in the pig, cat, and dog it is, on the
+contrary, reduced to a simple membrane. Indeed, in these
+latter, the abdominal viscera being less developed, the
+inferior wall of the abdomen does not require so strong a
+fibrous apparatus for supporting them. The great oblique,
+when it contracts, compresses the abdominal viscera in all
+circumstances under which this compression is necessary;
+it also acts as a flexor of the vertebral column.</p>
+
+<p><b>The Internal Oblique Muscle.</b>&mdash;This muscle, which is
+covered by the preceding, arises from the anterior superior
+iliac spine (external angle in ruminants and solipeds) and
+the neighbouring parts. From this origin its muscular
+fibres, the general direction of which is opposite to that of
+the fibres of the external oblique, diverging, proceed to
+terminate in an aponeurosis, which contributes to the
+formation of the <i>linea alba</i>, and to be attached superiorly
+to the internal surface of the last costal cartilages. It
+has the same action as the great oblique. What it presents<span class="pagenum"><a name="Page_138" id="Page_138">[138]</a></span>
+of special interest is the detail of form which it determines
+in the region of the flank; this detail is <i>the cord of the flank</i>.
+It is characterized by an elongated prominence which,
+starting from the iliac spine, is directed obliquely downwards
+and forwards, to terminate near the cartilaginous
+border of the false ribs.</p>
+
+<p>Often very apparent in the ox, and still more so in the
+cow, the cord in question contrasts with the depression
+which surmounts it; this depression is situated below the
+costiform processes of the lumbar vertebr&aelig;, and is called
+the <i>hollow of the flank</i>. It is so much the more marked
+as the mass of the intestinal viscera is of greater weight.</p>
+
+<p>We sometimes meet with a case of the presence of this
+hollow in the horse. But when in the latter, the flank
+is well formed, the hollow is scarcely visible, and the cord
+but slightly prominent. It is only in emaciated subjects
+that these details are found clearly marked.</p>
+
+<p><b>Transversalis Abdominis.</b>&mdash;This muscle being deeply
+situated does not present any interest for us. We will,
+however, point out, in order to complete the series
+of muscles which form the abdominal wall, that the
+direction of its fibres is transverse, and that they extend
+from the internal surface of the cartilages of the false
+ribs, and the costiform processes of the lumbar vertebr&aelig;
+to the <i>linea alba</i>.</p>
+
+<p><b>The Rectus Abdominis</b> (<a href="#Fig067">Fig. 67</a>, 13; <a href="#Fig068">Fig. 68</a>, 6).&mdash;This
+muscle, enclosed, as it is in man, in a fibrous sheath
+(<a href="#Fig067">Fig. 67</a>, 9) formed by the aponeuroses of the lateral
+muscles of the abdomen, is a long and wide fleshy band,
+which, as in the human species, reaches from the thorax to
+the pubis.</p>
+
+<p>What distinguishes it in quadrupeds is that there are
+costal attachments which extend further on the sternal
+surface of the thorax, and the number of its aponeurotic
+insertions, which, in general, is more considerable. These
+are, indeed, six or seven in number in the pig and in
+ruminants, and about ten in the horse.</p>
+
+<p>It is true that we may find but three in the cat and
+dog; still, we often find as many as six. These intersections<span class="pagenum"><a name="Page_139" id="Page_139">[139]</a></span>
+are not marked on their exterior by transverse grooves,
+such as we find in the human species in individuals with
+delicate skin and whose adipose tissue is not very much
+developed.</p>
+
+<p>The rectus abdominis is covered, in its anterior portion,
+by the sterno-trochinian muscle (posterior segment of the
+small pectoral). In contracting, this muscle brings the
+chest nearer the pelvis, and as a result flexes the vertebral
+column. It also contributes to the compression of the
+abdominal viscera.</p>
+
+<p><b>Pyramidalis Abdominis.</b>&mdash;This unimportant little
+muscle, which in man is situated at the lower part of the
+abdomen, extends from the pubis to the <i>linea alba</i>. It is
+not present in the domestic animals.</p>
+
+<p>We consider it interesting, however, to point out, although
+the fact is not a very useful one as regards external form,
+that this muscle is distinctly developed in marsupials.</p>
+
+<p>We know that in the opossum, the kangaroo, and the
+phalanger fox, the young are brought forth in an entirely
+incomplete state of development, and that, during a certain
+period, they are obliged to lodge in a pouch which is placed
+at the lower part of the abdomen of the mother. Now,
+this pouch contains the mammary glands; but the young,
+being too feeble to exercise the requisite suction, the
+pyramidal muscles come to their assistance. These muscles,
+in contracting, approximate to one another two bones which
+are placed above the pubis, the (so-called) marsupial bones
+(see <a href="#Fig080">Fig. 80</a>); by their approximation the bones in question,
+which are placed behind and on the outer side of the
+mammary glands, compress the latter, and thus is brought
+about the result which the little ones, on account of their
+feebleness, would, without that intervention, be incapable
+of obtaining for themselves.</p>
+
+<p class="pagenum"><a name="Page_140" id="Page_140">[140]</a></p>
+
+<h5><a name="Dorsals" id="Dorsals"></a>Muscles of the Back</h5>
+
+<p><b>Trapezius</b> (<a href="#Fig068">Fig. 68</a>, 1, 2; <a href="#Fig069">Fig. 69</a>,
+1, 2; <a href="#Fig070">Fig. 70</a>, 1, 2).&mdash;This
+muscle, more or less well developed, according to the
+species, is divided into two portions, of which the names
+indicate the respective situations&mdash;a cervical and a
+dorsal.</p>
+
+<p>These two parts, considered in the order in which we find
+them, take their origin from the superior cervical ligament
+and from the spinous processes of the first dorsal vertebr&aelig;.
+From these different points the fibres are directed towards
+the shoulder; the anterior are, consequently, oblique
+downwards and backwards, and the posterior are directed
+downwards and forwards. They are inserted into the
+scapula in the following manner: the fibres of the dorsal
+portion are attached to the tuberosity of the spine; those
+of the cervical region are also fixed into the same spine,
+but into a considerably larger surface.</p>
+
+<p>The cervical portion occupies, in the region of the neck,
+an area relatively smaller than the corresponding portion
+of the trapezius in man. This diminished degree of development
+results from the absence, complete, or nearly
+so, of the clavicle in the animals which we are now considering.
+We remember, that the trapezius of man is partly
+inserted into the clavicle, and the disappearance of this
+latter cannot fail to bring modifications in the general disposition
+of the corresponding portion of the muscle. There
+results a disconnection of this latter, and it becomes
+united to other muscular fibres to form a muscle with
+which we shall soon have to deal&mdash;the mastoido-humeral
+(see <a href="#Page_150">p. 150</a>).<span class="pagenum"><a name="Page_141" id="Page_141">[141]</a></span></p>
+
+<div class="figlarge"><a name="Fig068" id="Fig068"></a>
+<img src="images/illo164.png" alt="Fig. 68" width="600" height="309" />
+<p class="caption just">Fig. 68.&mdash;Myology of the Dog: Superficial Layer of Muscles.</p>
+
+<p class="subcaption just">1, Trapezius, cervical portion; 2, trapezius, dorsal portion; 3,
+superior outline of the scapula; 4, latissimus dorsi;
+5, external oblique muscle; 6, rectus abdominis; 7, pectoralis major of the right side; 8, pectoralis minor (sterno-trochinian);
+9, 9, mastoido humeral muscle; 10, tendinous intersection, at the level of which is found a rudimentary
+clavicle; 11, sterno-mastoid muscle; 12, infrahyoid muscles; 13, omo-tracheal or acromio-tracheal muscle;
+14, splenius; 15, levator anguli scapul&aelig;; 16, deltoid muscle, spinal portion; 17, deltoid, acromial portion; 18, superior
+extremity of the humerus; 19, supraspinatus; 20, infraspinatus; 21, biceps cubiti; 22, brachialis anticus; 23, triceps
+cubiti, long head; 24, triceps cubiti, external head; 25, olecranon process; 26, radialis (anterior extensor of the metacarpus);
+27, iliac crest; 28, gluteus maximus; 29, gluteus medius; 30, biceps cruris; 31, semitendinosus; 32, semi-membranosus;
+33, gastrocnemius; 34, tensor of the fascia lata; 35, sartorius; 36, fascia lata drawn up by the triceps;
+37, the patella or knee-cap; 38, ischio-coccygeal muscle; 39, superior sacro-coccygeal; 40, lateral sacro-coccygeal;
+41, inferior sacro-coccygeal.</p></div>
+
+<p>As specific differences we should add that the trapezius
+occupies a more or less extensive portion of the median
+and superior regions of the neck; terminating at a considerable
+distance from the head in the dog and horse, it,
+on the contrary, approaches it in the pig and in ruminants.
+The cervical portion, when it contracts, draws the scapula
+upwards and forwards, the dorsal portion draws it upwards<span class="pagenum"><a name="Page_142" id="Page_142">[142]</a></span>
+and backwards. When the trapezius acts as a whole the
+scapula is raised.</p>
+
+<p><b>The Latissimus Dorsi</b> (<a href="#Fig068">Fig. 68</a>, 4; <a href="#Fig069">Fig.
+69</a>, 5; <a href="#Fig070">Fig. 70</a>, 5).&mdash;This
+muscle arises by an aponeurosis, the so-called dorso-lumbar
+aponeurosis, from the spinous processes of the last
+dorsal vertebr&aelig; (the seven last in the dog, fourteen or
+fifteen last in the horse), from the spinous processes of the
+lumbar vertebr&aelig;, and from the last ribs. Its fleshy fibres
+are directed downwards and forwards, being more oblique
+in direction posteriorly, and pass on the inner side of the
+posterior muscular mass of the arm, to be inserted into
+the internal lip of the bicipital groove of the humerus,
+or, a little lower down, on the median portion of the
+internal surface of the same bone. This latter mode of
+insertion is met with in the horse and the ox.</p>
+
+<p>The anterior fibres cover the posterior angle of the scapula
+(as in man, where the corresponding angle, but in this case
+inferior, is covered by the same muscle), and, a little higher
+up, are in their turn concealed by a portion of the dorsal
+fibres of the trapezius. It covers, to a greater or less
+extent, the great serratus muscle. These relations are
+similar to those found in the human species.</p>
+
+<p>We find that the fleshy fibres of the great dorsal are
+prolonged more or less backwards if we examine this muscle
+in the dog, the ox, the pig, and the horse. Indeed, the fibres
+reach to the thirteenth rib in the dog and the cat (that is
+to say, the last rib), the eleventh in the ox, tenth in the
+pig, and twelfth only in the horse. We say &#8216;only&#8217; in connection
+with this last because it is necessary to remember
+that the ribs are eighteen in number on each side of the
+thorax of this animal, and that, accordingly, the fleshy
+fibres of the great dorsal muscle are, relatively, of small
+extent.</p>
+
+<p>When this muscle contracts it flexes the humerus upon
+the scapula, and helps to draw the whole of the anterior
+limb backwards and upwards.<span class="pagenum"><a name="Page_143" id="Page_143">[143]</a></span></p>
+
+<div class="figlarge"><a name="Fig069" id="Fig069"></a>
+<img src="images/illo166.png" alt="Fig. 69" width="600" height="329" />
+<p class="caption just">Fig. 69.&mdash;Myology of the Ox: Superficial Layer of Muscles.</p>
+
+<p class="subcaption just">1, Trapezius, cervical portion; 2, trapezius, dorsal portion; 3, outline of the scapula; 4, spine of the scapula;
+5, latissimus dorsi; 6, small posterior serratus; 7, prominence caused by the costiform processes of the lumbar vertebr&aelig;;
+8, serratus magnus; 9, external oblique; 10, pectoralis major (sterno-humeral); 11, mastoido-humeralis; 12, atlas;
+13, atlas; 14, parotid gland; 15, sterno-mastoid muscle; 16, infrahyoid muscles; 17, omo-trachelian or acromio-trachelian
+muscle; 18, deltoid; 19, brachialis anticus; 20, triceps, long head; 21, triceps, external head; 22, olecranon;
+23, radialis (anterior extensor of the metacarpus); 24, anterior iliac spine; 25, gluteus maximus; 26, gluteus medius;
+27, biceps cruris; 28, semitendinosus; 29, gastrocnemius; 30, tensor of the fascia lata; 31, fascia lata covering the triceps
+of the thigh; 32, patella; 33, ischio-coccygeal muscle; 34, superior ischio-coccygeal; 35, lateral ischio-coccygeal;
+36, inferior ischio-coccygeal.</p></div>
+
+<p>There is a muscular fasciculus which, because of its
+relations with the muscle we have just been studying, is
+known as the <i>supplementary muscle of the latissimus dorsi</i>.<span class="pagenum"><a name="Page_144" id="Page_144">[144]</a></span>
+But as, on the other hand, this fasciculus is in relation
+with the triceps, we shall in preference consider it in relation
+with this latter (see <a href="#Page_173">p. 173</a>).</p>
+
+<p>The aponeurosis by which the great dorsal arises from
+the vertebral column covers, as in man, the muscles which
+occupy the grooves situated on each side of the spinous
+processes&mdash;the spinal muscles or common muscular mass,
+if we regard them as a whole (<a href="#Fig070">Fig. 70</a>, 7); the sacro-lumbar
+and the long dorsal muscles covering the transverse spinal,
+if we consider them as distinct.</p>
+
+<p>It would be superfluous to enter here into a detailed
+examination of these muscles.</p>
+
+<p>If they are but little developed the spinous processes
+become prominent under the skin; if they are more so they
+may by their thickness project beyond the level of these
+processes, and these latter thus come to lie in a groove more
+or less marked, which, on account of the division which is
+determined by its presence, has caused the regions which
+it occupies to be designated by the names <i>double back</i> and
+<i>double loins</i>.</p>
+
+<p>The muscles are extensors of the vertebral column.</p>
+
+<p>Under the aponeurosis of the great dorsal muscle there is
+found in man another muscle, the serratus posticus inferior,
+which, on account of being deeply placed and its slight
+thickness, offers nothing of interest in connection with
+the study of external form. It arises from the spinous
+processes of the three last dorsal vertebr&aelig; and those of
+the three first lumbar; it then passes upwards and outwards,
+and divides into four digitations, to be inserted into
+the inferior borders of the four last ribs. We repeat that
+it is covered by the great dorsal muscle.</p>
+
+<p>In the pig, ox, and horse, which have this latter muscle
+less developed in its posterior portion, the same small
+serratus muscle, known as the <i>posterior serratus</i>, is visible
+in the superficial layer of muscles (<a href="#Fig069">Fig. 69</a>, 6; <a href="#Fig070">Fig. 70</a>, 6).
+The number of its digitations is more or less considerable
+according to the species examined.</p>
+
+<p><b>The Rhomboid Muscle</b> (<a href="#Fig070">Fig. 70</a>, 21).&mdash;In order to
+make intelligible the position of the rhomboid in the superficial<span class="pagenum"><a name="Page_145" id="Page_145">[145]</a></span>
+layer in quadrupeds, it appears to us necessary to
+recall the anatomical characters of the muscle as found in
+man. The rhomboid arises from the inferior portion of the
+posterior cervical ligament, from the spinous process of the
+seventh cervical vertebr&aelig; and the four or five upper dorsal;
+thence passing obliquely downwards and outwards, it is inserted
+into the spinal border of the scapula, into the portion
+of this border which is situated below the spine; it sometimes
+extends to the middle of the interval which separates
+this latter from the superior internal angle of the same
+bone.</p>
+
+<p>The portion of the muscle which arises from the cervical
+ligament and the seventh cervical vertebra is often separated
+from the lower portion by a cellular interspace. For this
+cause some anatomists have described the rhomboid as
+consisting of two parts&mdash;the superior or small rhomboid
+and the inferior or large rhomboid, on account of the position
+occupied by each, and of their difference in volume.</p>
+
+<p>This muscle can only be seen in the region of the back, in
+the space limited externally by the spinal border of the
+scapula, below by the latissimus dorsi, and internally by the
+trapezius, which covers it in the rest of its extent. It is
+not in this space that it is seen in certain quadrupeds. As
+we pointed out in the section on osteology, the spinal border
+of the scapula is short, and it seems to be due to this
+limitation in length that the trapezius and the latissimus dorsi
+muscle are, at this level, in contact the one with the other
+in such a way that they fill up the interval in which the
+rhomboid is seen in man.</p>
+
+<p>In the horse we can partly see it in the superficial muscular
+layer, but in the region of the neck only, at the superior
+border of the shoulder. Indeed, as we have already pointed
+out, the trapezius does not reach the occipital protuberance;
+for this reason a part of the anterior portion of the rhomboid
+may be seen&mdash;that is, the portion which corresponds to the
+superior part of the human muscle.<span class="pagenum"><a name="Page_146" id="Page_146">[146]</a></span></p>
+
+<div class="figlarge"><a name="Fig070" id="Fig070"></a>
+<img src="images/illo169.png" alt="Fig. 70" width="600" height="347" />
+<p class="caption just">Fig. 70.&mdash;Myology of the Horse: Superficial
+Layer of Muscles.</p>
+
+<p class="subcaption just">1, Trapezius, cervical
+portion; 2, trapezius,
+dorsal portion;
+3, superior outline
+of the scapula;
+4, spine of the scapula;
+5, latissimus dorsi
+muscle; 6, small posterior
+serratus; 7,
+spinal muscles, or
+common muscular
+mass; 8, ribs; 9, serratus magnus; 10,
+external oblique; 11, pectoralis major
+(sterno-humeral); 12, pectoralis minor
+(sterno-trochinian); 13, atlas; 14, parotid gland; 15, mastoido-humeralis; 16, point of the arm; 17, sterno-mastoid, or sterno-maxillary;
+18, jugular groove; 19, infrahyoid muscles; 20, omo-trachelian muscle; 21, rhomboid; 22, splenius; 23, levator
+anguli scapul&aelig;; 24, deltoid; 25, supraspinatus; 26, terminal part of the sterno-prescapular, a portion of the small
+pectoral muscle; 27, brachialis anticus; 28, triceps cubiti, middle or long head; 29, triceps cubiti, external head; 30, olecranon;
+31, radial extensor (anterior extensor of the metacarpus); 32, anterior iliac spine; 33, anterior portion of the gluteus maximus&mdash;the
+aponeurosis of the muscle has been divided in order to expose the gluteus medius; 34, posterior portion of the
+gluteus maximus; 35, gluteus medius; 36, biceps cruris; 37, semitendinosus; 38, point of the buttock; 39, gastrocnemius;
+40, tensor of the fascia lata; 41, triceps cruris; 42, ischio-coccygeal muscle; 43, superior sacro-coccygeal; 44, lateral sacro-coccygeal;
+45, inferior sacro-coccygeal.</p></div>
+
+<p>But whether it be covered by the trapezius, or, as we
+find in the cat and dog, by the <i>mastoido-humeral muscle</i>
+(see <a href="#Page_150">p. 150</a>), which is very broad in this region, we do not
+the<span class="pagenum"><a name="Page_147" id="Page_147">[147]</a></span>
+less recognise its presence; and in the horse and ox, in particular,
+it forms an elongated prominence beginning at the
+level of the scapula, and tapering as it ascends, towards
+the posterior part of the head.</p>
+
+<p>Its origins are similar to those which we have already
+described in the human rhomboid. It arises from the cervical
+ligament and the spinous processes of the foremost
+dorsal vertebr&aelig;; its fibres converge and pass to the scapula,
+to be inserted into its superior or spinal border, or into the
+internal surface of the cartilage of prolongation.</p>
+
+<p>It assists in keeping the scapula applied to the thoracic
+cage, and when it contracts, draws the scapula upwards
+and forwards.</p>
+
+<p>Taking its fixed point at the scapula, it acts on the neck
+by its anterior fibres, and extends it.</p>
+
+<p>We shall soon have occasion to mention this muscle again,
+in connection with the study of the muscles of the neck.</p>
+
+<p><b>The Cutaneous Muscle of the Trunk</b> (<a href="#Fig071">Fig. 71</a>).&mdash;Immediately
+beneath the skin which covers the neck,
+shoulders, and trunk is found a vast cutaneous muscle,
+analogous to that which, in the human species, exists only
+in the cervical region.</p>
+
+<p>This thin muscle, whose function is to move the skin
+which strongly adheres to it, and in this way to remove
+from it material causes of irritation (insects, for example),
+is of considerable thickness in the region of the trunk;
+where it constitutes what certain authors have designated
+by the name of <i>panniculus carnosus</i>. In this region it extends
+from the posterior border of the shoulder to the thigh, and,
+in the vertical direction, from the apices of the spinous
+process of the dorso-lumbar vertebr&aelig; to the median line of
+the abdomen.</p>
+
+<p>Arising above from the supraspinous ligament of the dorso-lumbar
+and sacral regions (except in the carnivora; see
+below) by an aponeurosis which, posteriorly, covers the
+muscles of the hind-limbs, its fibres are directed to the elbow,
+on which they are arranged in two layers: a superficial,
+which becomes continuous with the panniculus muscle of
+the shoulder; and a deep, which passes on the inner<span class="pagenum"><a name="Page_148" id="Page_148">[148]</a></span>
+side of the shoulder to be inserted into the internal surface
+of the humerus; this latter exists only in the dog and
+cat.</p>
+
+<p>The most inferior fibres, behind, at the level of the
+knee-cap form a triangular process which in the horse
+receives the name of the <i>stifle fold</i>, from the name
+veterinarians give to the region of the articulation of the
+knee. This fold of skin, which commences on the antero-internal
+surface of this region, is directed upwards, and
+then forwards, to end by gradually disappearing over the
+corresponding part of the abdomen.</p>
+
+<div class="figmed"><a name="Fig071" id="Fig071"></a>
+<img src="images/illo171.png" alt="Fig. 71" width="450" height="210" />
+<p class="caption just">Fig. 71.&mdash;Myology of the Horse: Panniculus Muscle of the Trunk.</p></div>
+
+<p>In the same animal the muscular fibres of the panniculus
+of the trunk arise along a line which connects the stifle-joint
+to the withers, a line which is, consequently, oblique upwards
+and forwards. Now, as the fleshy layer is thicker
+than the aponeurosis, the result is that the mode of constitution
+of this muscle can be recognised under the skin.
+Indeed, we can see in some animals, occasionally very distinctly,
+a slight elevation starting from the region of the
+abdomen in the neighbourhood of the knee, and thence
+directed obliquely upwards and forwards. This elevation
+is produced by the fleshy portion of the panniculus.</p>
+
+<p>In the carnivora, the panniculus of the trunk is not
+attached to the supraspinous ligament; it is blended with
+the same muscle of the opposite side, passing over the
+spinous region of the vertebral column.</p>
+
+<p>From this arrangement results a great mobility of the
+skin which covers the back. Further, it explains why it is<span class="pagenum"><a name="Page_149" id="Page_149">[149]</a></span>
+possible to lift up this skin along with the panniculus which
+it covers, and to which it adheres, throughout the whole
+extent of the dorso-lumbar column. As we pointed out
+above, there is also a panniculus muscle of the shoulder
+and one of the neck. We will deal with them when treating
+of the regions to which those muscles belong.</p>
+
+<h5>The Coccygeal Region</h5>
+
+<p>As a sequel to the study of the muscles of the region of
+the trunk very naturally comes the description of those which,
+belonging to the region of the coccyx, are destined for the
+movements of the caudal appendix, of which this latter
+constitutes the skeleton. The muscles may not seem to
+be of much importance with regard to external form, but,
+as they form part of the superficial muscular layer, and
+as the mass of each is seen in the form of the tail in some
+animals (the lion, for example), they merit our attention for
+a moment. A few lines will suffice to give an idea of them.
+They are: the <i>ischio-coccygeal</i>, <i>superior sacro-coccygeal</i>, <i>lateral
+sacro-coccygeal</i>, and <i>inferior sacro-coccygeal</i>.</p>
+
+<p><b>The Ischio-coccygeal</b> (<a href="#Fig018">Fig. 18</a>, 38; <a href="#Fig069">Fig. 69</a>,
+33; <a href="#Fig070">Fig. 70</a>, 42).&mdash;This
+muscle, triangular in shape, better developed in the
+carnivora than in the horse, arises from the spine of the
+ischium, or from the supracotyloid crest, which replaces
+this latter in the solipeds and the ruminants. Thence its
+fleshy mass is directed upwards, expanding as it proceeds to
+be inserted into the transverse processes of the first two
+coccygeal vertebr&aelig; after insinuating itself between two of the
+following muscles, the lateral and inferior sacro-coccygeal.</p>
+
+<p>In the dog and cat, the muscle is in great part covered by
+the great gluteal. In the ox, by a peculiar arrangement of
+the corresponding region of the <a href="#ThighMuscles">muscles of the thigh</a>&mdash;an
+arrangement which we will examine in connection with the
+study of the latter&mdash;it is more exposed than in the horse,
+and gives origin to an outline which corresponds to its general
+form in the region situated immediately below the root of
+the tail.</p>
+
+<p>It is a depressor of the whole caudal appendix.</p>
+
+<p><span class="pagenum"><a name="Page_150" id="Page_150">[150]</a></span><b>The
+Superior Sacro-coccygeal</b> (<a href="#Fig068">Fig. 68</a>, 39; <a href="#Fig069">Fig. 69</a>, 34;
+<a href="#Fig070">Fig. 70</a>, 43).&mdash;The fasciculi which form this muscle
+arise from the crest of the sacrum, and proceed thence to
+end successively on the coccygeal vertebr&aelig;. It is in contact
+in the middle line with the corresponding muscle of the
+opposite side.</p>
+
+<p>It raises the tail and inclines it laterally; if the muscle
+of one side contracts at the same time as that of the other
+the tail is elevated directly.</p>
+
+<p><b>The Lateral Sacro-coccygeal</b> (<a href="#Fig068">Fig. 68</a>, 40; <a href="#Fig069">Fig. 69</a>, 35;
+<a href="#Fig070">Fig. 70</a>, 44).&mdash;Situated on the lateral part of the caudal
+region, this muscle arises, in the dog, from the internal border
+of the iliac bone and the external border of the sacrum; in
+the horse, it arises from the crest of the sacrum. It is inserted
+into the coccygeal vertebr&aelig;.</p>
+
+<p>It produces lateral movement of the tail.</p>
+
+<p><b>The Inferior Sacro-coccygeal</b> (<a href="#Fig068">Fig. 68</a>, 41; <a href="#Fig069">Fig. 69</a>, 36;
+<a href="#Fig070">Fig. 70</a>, 43).&mdash;This muscle, which is fairly thick, arises from
+the inferior surface of the sacrum and the corresponding
+surface of the sacro-sciatic ligament; it is inserted into
+the coccygeal vertebr&aelig;.</p>
+
+<p>It depresses the caudal appendix.</p>
+
+<h5><a name="NeckMuscles" id="NeckMuscles"></a>Muscles of the Neck</h5>
+
+<p><b>Mastoido-humeralis</b> (<a href="#Fig066">Fig. 66</a>, 3; <a href="#Fig068">Fig. 68</a>, 9, 9, 10;
+<a href="#Fig069">Fig. 69</a>, 12; <a href="#Fig070">Fig. 70</a>, 15).&mdash;One of the most important
+muscles of the region of the neck in man is the sterno-cleido
+mastoid. We recollect that, in its inferior part, it is divided
+into two bundles, one of which arises from the manubrium
+of the sternum, and the other from the inner third of the
+clavicle, whence the denominations of the <i>sternal</i> portion
+and <i>clavicular</i> portion. The muscle formed by the union
+of these two portions is then directed obliquely outwards,
+backwards, and upwards, to be inserted into the mastoid
+process of the temporal bone and the two external thirds of
+the superior curved line of the occipital bone.</p>
+
+<p>Now, the animals which we are here considering have but
+a rudimentary clavicle or are entirely without it. From<span class="pagenum"><a name="Page_151" id="Page_151">[151]</a></span>
+the absence of this item of the skeleton there necessarily
+result modifications in the arrangement of the muscles of
+this region, which we must at the very outset explain, before
+undertaking the special study of the muscle which is the
+subject of the present paragraph.</p>
+
+<p>Let us suppose, for the more definite arrangement of our
+ideas, that the clavicle is altogether absent, although we
+do find it in a rudimentary state in some animals and
+completely developed in others (marmot, bat), and we will
+proceed to indicate what this absence determines.</p>
+
+<p>The great pectoral muscle in man arises in part from the
+clavicle; this origin not being possible in animals which have
+no clavicle, its attachments, as we have already seen, are
+concentrated on the sternum. The trapezius in man similarly
+arises in part from the clavicle; for the reasons above indicated
+its clavicular fasciculi cannot exist in distinct form in
+the animals which have no clavicle.</p>
+
+<p>The sterno-cleido mastoid, whose inferior attachments we
+mentioned above, cannot have a clavicular portion.</p>
+
+<p>It is the same in the case of the deltoid, which, we know,
+arises in part from the anterior bone of the shoulder.</p>
+
+<p>Of the four muscles which have partial clavicular origins
+in man, two are known to us in connection with animals&mdash;the
+great pectoral and the trapezius. What has become
+of the other two, the sterno-cleido mastoid and the
+deltoid?</p>
+
+<p>It is this which we now proceed to investigate. After a
+fashion simple enough, but which it is necessary to describe,
+the clavicular fasciculi of the trapezius and the corresponding
+fasciculi of the sterno-cleido mastoid are united the one
+to the other; the portion of the deltoid which in man
+arises from the clavicle, by reason of the absence of this
+latter, is also combined with the fleshy mass formed by
+the preceding muscles. From this fusion results the
+muscle known as the mastoido-humeral. This muscle,
+which consists of a long fleshy band situated on the
+lateral aspect of the neck, takes its origin, as a general
+rule, from the posterior surface of the skull and the upper
+part of the neck, from which it passes obliquely downwards<span class="pagenum"><a name="Page_152" id="Page_152">[152]</a></span>
+and backwards, covering the scapulo-humeral angle&mdash;that is,
+the region known as the point of the shoulder or arm&mdash;and
+is inserted into the anterior border of the humerus, the
+border which, limiting anteriorly the musculo-spiral groove,
+forms a continuation of the deltoid impression. On account
+of the regions with which it is related, Bourgelat named this
+muscle <i>the muscle common to the head, neck, and arm</i>.</p>
+
+<p>It is at the level of the scapulo-humeral angle that the
+vestiges of the clavicle are found.</p>
+
+<p>This bone is represented in some animals&mdash;the pig, ox,
+and horse&mdash;by a single tendinous intersection, more or less
+apparent, which extends transversely from the scapula to
+the anterior extremity of the sternum. In the dog and the
+cat, we find, besides, on the deep surface of the muscle and
+at the level of this tendinous intersection, the rudiment of
+the clavicle of which we made mention in the section on
+Osteology (see <a href="#Page_25">p. 25</a>).</p>
+
+<p>It is beneath the intersection, the existence of which we
+have just pointed out, that is found that portion of the
+mastoido-humeral muscle which corresponds to the clavicular
+fasciculi of the deltoid; that portion which is situated above
+the intersection corresponds to the clavicular fibres of the
+sterno-cleido-mastoid and of the trapezius.</p>
+
+<p>The mastoido-humeral presents certain varieties in different
+animals.</p>
+
+<p>In the dog and the cat, this muscle, which is blended above
+with the sterno-mastoid (see <a href="#Page_153">p. 153</a>), to be inserted with it
+into the mastoid process and the mastoid crest, covers the
+neck for a considerable extent from the superior curved line
+of the occipital bone to which it is attached, to the trapezius
+with which it unites posteriorly, but from which it separates
+below. Between these two extreme points of its superior
+portion it is attached to the cervical ligament.</p>
+
+<p>In the pig and in ruminants, in which the trapezius
+approaches more closely to the head, the mastoido-humeral
+occupies, in consequence, a less extent of the cervical region.</p>
+
+<p>In the horse, the mastoido-humeral neither covers the
+neck nor joins the trapezius; indeed, we have already
+shown that it is separated by a considerable distance from<span class="pagenum"><a name="Page_153" id="Page_153">[153]</a></span>
+the head. In the limited interval between these two
+muscles a part of the rhomboid and parts of other muscles
+are seen with which we shall soon be occupied.</p>
+
+<p>This muscle, as regards the horse, is described by some
+anatomists as consisting of two parts: one anterior, or
+superficial; the other posterior, or deep. In reality, the
+first only corresponds to the mastoido-humeral, which
+we are considering; the posterior may be more exactly
+regarded as representing a special muscle of quadrupeds,
+but which is here a little deformed, the <i>omo-trachelian</i> (see
+<a href="#Page_155">p. 155</a>).</p>
+
+<p>When the mastoido-humeral contracts, taking its fixed
+point above, it acts as an extensor of the humerus, and
+carries the entire fore-limb forwards. If it takes its fixed
+point below&mdash;that is to say, at the humerus&mdash;it inclines
+the head and neck to its own side. If it contracts at the
+same time as the mastoido-humeral of the opposite side,
+then the head and the neck are carried into the position of
+extension.</p>
+
+<p><b>The Sterno-mastoid</b> (<a href="#Fig066">Fig. 66</a>, 5; <a href="#Fig068">Fig. 68</a>, 11; <a href="#Fig069">Fig. 69</a>, 15;
+<a href="#Fig070">Fig. 70</a>, 17).&mdash;Having described the clavicular portion of
+the sterno-cleido-mastoid in connection with the mastoido-humeral,
+because it forms a part of the latter, we have,
+in order to complete the homologies of this muscle, to study
+now that which corresponds to its sternal portion. This is
+the <i>sterno-mastoid</i> muscle. In all the quadrupeds with which
+we are here concerned this muscle arises from the anterior
+extremity of the sternum; narrow and elongated in form,
+it passes towards the head in a direction parallel to the
+anterior border of the mastoido-humeral, from which it is
+separated by an interspace which, along its whole length,
+lodges superficially the jugular vein; hence the name of
+<i>jugular groove</i>, which is given to this part of the neck
+(<a href="#Fig010">Fig. 10</a>, 18).</p>
+
+<p>It is inserted, in the case of the dog and cat, into the
+mastoid process, where it is united with the mastoido-humeral;
+in the ox it is divided into two portions&mdash;one
+which goes to the base of the occipital bone, the other
+passing in front of the masseter is by the medium of the<span class="pagenum"><a name="Page_154" id="Page_154">[154]</a></span>
+aponeurosis of this latter attached to the zygomatic crest.
+This latter part is considered by some writers as forming
+a portion of the panniculus muscle of the neck.</p>
+
+<p>In the horse it is attached to the angle of the lower jaw
+by a tendon, which an aponeurosis that passes under the
+parotid gland binds to the mastoido-humeral muscle and
+the mastoid process.</p>
+
+<p>By reason of this insertion into the jaw, in the case of
+the solipeds, this muscle is further named the <i>sterno-maxillary</i>.</p>
+
+<p>When it contracts, it flexes the head, and inclines it
+laterally. This movement is changed to direct flexion when
+the two sterno-mastoid muscles contract simultaneously.</p>
+
+<p>In man, the sterno-cleido-mastoid and the trapezius
+leave a triangular space between them, which, being limited
+inferiorly by the middle third of the clavicle, is known as
+the supraclavicular region; this region, being depressed,
+especially in its inferior part, has also been given the name
+of supraclavicular fossa&mdash;popularly called the &#8216;<i>salt-cellar</i>.&#8217;</p>
+
+<p>The muscles which form the floor of this region, passing
+from above downwards, are: a very small portion of
+the complexus, splenius, levator anguli scapul&aelig;, posterior
+scalenus, and anterior scalenus; then, crossing these latter,
+and most superficial, is the omo-hyoid muscle.</p>
+
+<p>An analogous region, but of only slight depth, exists in
+quadrupeds; its borders are formed by the mastoido-humeral
+and trapezius muscles.</p>
+
+<p>It is not limited below by the clavicle&mdash;we know, indeed,
+that this, or the intersection which represents it, belongs
+to the mastoido-humeral muscle&mdash;but by the inferior portion
+of the spine of the scapula.</p>
+
+<p>It is of greater or less extent according to the species
+considered.</p>
+
+<p>In the dog, cat, pig, and ox, it is narrow, for the muscles
+which bound it approach one another pretty closely. It has,
+as in man, the form of a triangle, with the apex above.
+In the horse it is much broader, and, contrary to the
+arrangement which it presents in the human species, the
+widest part is directed upwards.</p>
+
+<p><span class="pagenum"><a name="Page_155" id="Page_155">[155]</a></span>The muscles which we find there are, consequently, more
+or less numerous. In the dog and cat they are: a portion
+of a muscle which we do not normally meet with in man&mdash;the
+<i>omo-trachelian</i>&mdash;then in a decreasing extent: supraspinatus,
+levator anguli scapul&aelig; and splenius.</p>
+
+<p>In the pig: the omo-trachelian, supraspinatus, and the
+terminal portion of the sterno-prescapular&mdash;the anterior
+part of the lesser or deep pectoral muscle.</p>
+
+<p>In the ox: the omo-trachelian only.</p>
+
+<p>But in the horse we find the omo-trachelian, the supraspinatus,
+and the terminal extremity of the sterno-prescapular;
+then in a larger extent of area the levator anguli
+scapul&aelig; and the splenius; and, finally, the anterior portion
+of the rhomboid.</p>
+
+<p>Among the muscles which we have just enumerated are
+some that we have already studied; these are the sterno-prescapular
+and the rhomboid. We will examine the <a href="#Supraspinatus">supraspinatus</a>
+muscle in connection with the region of the shoulder.</p>
+
+<p>As to the scaleni muscles and the complexus, they are
+deeply situated, whereas the omo-hyoid is visible in the
+anterior region of the neck only.</p>
+
+<p>There remain for us, accordingly, to examine, at the
+present juncture, but the omo-trachelian, levator anguli
+scapul&aelig;, and splenius muscles.</p>
+
+<p><b>The Omo-trachelian Muscle</b> (<a href="#Fig068">Fig. 68</a>, 13; <a href="#Fig069">Fig. 69</a>, 17;
+<a href="#Fig070">Fig. 70</a>, 20).&mdash;Also called the <i>acromio-trachelian</i>, <i>levator
+ventri scapul&aelig;</i>,<a name="FNanchor_21_21" id="FNanchor_21_21"></a><a href="#Footnote_21_21"
+class="fnanchor">[21]</a> the <i>angulo-ventral muscle</i>, and the
+<i>transverso-scapular</i>,<a name="FNanchor_22_22" id="FNanchor_22_22"></a><a href="#Footnote_22_22" class="fnanchor">[22]</a>
+etc., this muscle is described by some hippotomists
+as belonging to the mastoido-humeral, of which it then
+forms its posterior or deep portion (see <a href="#Page_153">p. 153</a>).</p>
+
+<div class="footnote"><p><a name="Footnote_21_21" id="Footnote_21_21"></a><a href="#FNanchor_21_21"><span class="label">[21]</span></a>
+Ventri, because inserted into the inferior part of the spine of the
+scapula, towards the acromion&mdash;that is, on the ventral side&mdash;by contrast
+with the trapezius, which is attached higher up (dorsal side) on the same
+process.</p></div>
+
+<div class="footnote"><p><a name="Footnote_22_22" id="Footnote_22_22"></a><a href="#FNanchor_22_22"><span class="label">[22]</span></a>
+Among the many names given to this muscle, Arloing and Lesbre
+recommend the adoption of the name &#8216;transverse scapular&#8217; given by
+Straus-Durckheim, or &#8216;transverse of the shoulder&#8217; (Arloing and Lesbre,
+&#8216;Suggestions for the Reform of Veterinarian Muscular Nomenclature,&#8217;
+Lyons, 1898).</p></div>
+
+<p>The omo-trachelian muscle is found in all mammalia,<span class="pagenum"><a name="Page_156" id="Page_156">[156]</a></span>
+man alone excepted. It is, however, sometimes found in
+the human being; but it then constitutes an anomaly.</p>
+
+<p>In the dog, pig, and ox, it arises from the inferior part
+of the spine of the scapula, in the region of the acromion, and
+terminates on the lateral portion of the atlas.</p>
+
+<p>In the cat it is attached besides to the base of the occipital
+bone. It is visible in the space limited by the trapezius
+and the mastoido-humeral, the direction of which it crosses
+obliquely.</p>
+
+<p>In the horse it appears to be blended in clearly defined
+fashion with the mastoido-humeral. Attached below, like
+this latter, to the anterior border of the humerus, it covers
+the scapulo-humeral angle; and is attached by its upper
+portion to the transverse processes of the first four cervical
+vertebr&aelig;.</p>
+
+<p>We remember that the transverse processes are often,
+from their relation with the trachea, known as the tracheal
+processes. Hence the word &#8216;trachelian,&#8217; which forms part
+of the name of the muscle with which we are now dealing.</p>
+
+<p>By its contraction it helps to draw the anterior limb
+forwards.</p>
+
+<p>When this muscle, as an abnormality, exists in man, it
+arises from the clavicle or the acromion process, traverses
+the supraclavicular fossa, and is inserted into the transverse
+processes of the atlas or axis, or of both these
+vertebr&aelig;, or of the cervical vertebr&aelig; below these latter.
+It is then known by the names of the <i>elevator of the clavicle</i>
+or <i>elevator of the scapula</i>, and, finally, as the <i>cleido-omo-transversalis</i>
+(Testut).<a name="FNanchor_23_23" id="FNanchor_23_23"></a><a href="#Footnote_23_23" class="fnanchor">[23]</a></p>
+
+<div class="footnote"><p><a name="Footnote_23_23" id="Footnote_23_23"></a><a href="#FNanchor_23_23"><span class="label">[23]</span></a>
+L. Testut, &#8216;Les anomalies musculaires chez l&#8217;homme expliqu&eacute;es
+par l&#8217;anatomie compar&eacute;e,&#8217; Paris, 1884, p. 97. A. F. Le Double, &#8216;Trait&eacute;
+des variations du syst&egrave;me musculaire de l&#8217;homme et de leur signification
+au point de vue de l&#8217;anthropologie zoologique,&#8217; Paris, 1897, t. i., p. 235.</p></div>
+
+<p><b>The Levator Anguli Scapul&aelig;</b> (<a href="#Fig068">Fig. 68</a>, 15; <a href="#Fig070">Fig. 70</a>, 23).&mdash;As
+we have pointed out (p. 136), the levator anguli scapul&aelig;,
+because of its connections with the great serratus, is sometimes
+described with it. But inasmuch as in human anatomy
+these two muscles are considered separately, and that, in
+the superficial layer of muscles, they are seen in different<span class="pagenum"><a name="Page_157" id="Page_157">[157]</a></span>
+regions&mdash;the great serratus in the thoracic, and the levator
+anguli scapul&aelig; in the cervical&mdash;we prefer to study them
+separately.</p>
+
+<p>We remember that in man this muscle arises from the
+transverse processes of the upper cervical vertebr&aelig; and is
+inserted into the superior portion of the spinal border of the
+scapula, into the portion of this border which is situated
+above the spine; it also contributes to the formation of the
+floor of the supraclavicular region.</p>
+
+<p>When it contracts, it draws the superior portion of the
+scapula forwards and upwards, and causes a see-saw movement,
+for at the same time the inferior angle of the scapula
+is directed backwards. Taking its fixed point at the
+shoulder, it directly extends the neck if the muscle of one
+side acts at the same time as that of the opposite; but
+if only one muscle contracts it inclines the neck to the corresponding
+side.</p>
+
+<p>It is to be noticed that during movements a little more
+active than the ordinary the levator anguli scapul&aelig;, as
+moreover the other muscles of the neck do, becomes very
+distinct. We have, indeed, often remarked that, apart from
+these movements, each time the support of one of the fore-limbs
+is brought into requisition a brusque contraction of the
+muscles of this region accompanies it.</p>
+
+<p>This contraction gives the impression that, as on the one
+hand, each support determines a momentary arrest of
+progression, a jolt, and on the other hand, the head continues
+to be projected in the forward direction, the latter
+should be retained. But it cannot be so except by an effort
+in the opposite direction&mdash;that is to say, by the brusque
+contraction which we have just pointed out.</p>
+
+<p>Analogous contractions also take place in a man while
+running at the beginning of each contact of the lower limbs
+with the ground.</p>
+
+<p>We may add, apropos of this latter, that displacements
+of the head, sometimes in very pronounced fashion, take
+place during simple walking, and that every time one of
+the lower limbs is carried forwards the head is projected
+in the same direction. These displacements, which we<span class="pagenum"><a name="Page_158" id="Page_158">[158]</a></span>
+also find take place in the horse in pacing, especially in
+the region of the neck and head, seem then to have the
+effect of aiding the progression of the body forwards.</p>
+
+<p>They occur especially in animals when drawing a heavy
+load, and in individuals whose walking movements are
+executed with difficulty.</p>
+
+<p>It is necessary to repeat that, in these cases, the individual
+appears to assist the movement of his body by the impetus
+which the projection of his head forward determines, in
+order to add&mdash;and it is for this that we have referred to the
+subject&mdash;that during the intervals between each projection
+the head is carried backwards by a muscular contraction
+similar to that above discussed.</p>
+
+<p><b>The Splenius</b> (<a href="#Fig068">Fig. 68</a>, 14; <a href="#Fig070">Fig. 70</a>, 22).&mdash;In man, this
+muscle is attached in the median line to the inferior half
+or two-thirds of the posterior cervical ligament, to the
+spinous processes of the seventh cervical, and four or five
+upper dorsal vertebr&aelig;; it passes obliquely upwards and outwards,
+becomes visible in the supraclavicular region, passes
+under the sterno-cleido-mastoid, and proceeds to duplicate
+the cranial insertions of this latter; and, further, the most
+external fasciculi of this muscle are inserted into the transverse
+processes of the atlas and the axis.</p>
+
+<p>These separate superior attachments, and the division of
+the muscle which results, have caused the splenius to be
+regarded as formed of two portions: splenius of the head,
+and splenius of the neck.</p>
+
+<p>In the horse, this muscle, which is of voluminous dimensions,
+arises from the superior cervical ligament, and the
+spinous processes of the first four or five dorsal vertebr&aelig;;
+thence it proceeds to be inserted into the mastoid crest,
+and the transverse processes of the atlas and three or four
+vertebr&aelig; following.</p>
+
+<p>The region occupied superficially by the splenius is remarkable
+for the prominence which this muscle, with the
+deeply-seated complexus, which is equally bulky, determines
+at this level; it is situated above that region of the
+neck, in which are seen in part the fasciculi of the levator
+anguli scapul&aelig;. It terminates above and in front in the<span class="pagenum"><a name="Page_159" id="Page_159">[159]</a></span>
+ridge, which is sometimes very pronounced, which the
+transverse processes of the atlas make on each side of this
+part of the neck.</p>
+
+<p>In the dog and the cat, the superior and anterior region
+of the neck is thick and of rounded form, on account of the
+development which the splenius presents in those animals;
+but it is covered by the mastoido-humeral.</p>
+
+<p>This latter relation is also found in the ox, but the splenius
+in this case is but slightly developed.</p>
+
+<p>When the splenius contracts it extends the head and neck,
+while inclining them to its own side.</p>
+
+<p>If the splenius of one side contracts at the same time as
+that of the opposite, the extension takes place in a direct
+manner&mdash;that is to say, without any modifying lateral
+movement.</p>
+
+<h5>Infrahyoid Muscles</h5>
+
+<p>Having studied the lateral surfaces of the neck, we must
+now examine the anterior part of this region. Here, between
+the two sterno-mastoid muscles, we find a space broader
+above than below, in which are situated the larynx and the
+trachea, to the general arrangement of which is due the
+cylindrical form which this region presents. This space
+corresponds to that which in the neck of man is limited
+laterally by the sterno-cleido-mastoid muscles, below by
+the fourchette of the sternum, and above by the hyoid
+bone. In animals, as in man, it is called the infrahyoid
+region.</p>
+
+<p>The hyoid bone in quadrupeds is situated between the two
+rami or branches of the lower jaw. Owing to this disposition,
+the region above this bone, instead of having its surface
+projecting a little beyond the inferior border of the maxillary
+bone, is depressed. This is especially so in the horse. It
+is there that we find in this animal the region known as the
+<i>trough</i> (<i>auge</i>); the larynx corresponds to that part known as
+the <i>gullet</i>.</p>
+
+<p>The muscles which occupy the infrahyoid region are: the
+sterno-thyroid, the sterno-hyoid, and the omo-hyoid. There<span class="pagenum"><a name="Page_160" id="Page_160">[160]</a></span>
+is also a thyro-hyoid, but because of its deep situation and
+its slight importance it offers no interest from our point of
+view.</p>
+
+<p><b>Sterno-thyroid and the Sterno-hyoid Muscles.</b>&mdash;These
+two muscles, long, narrow, and flat, arise from the anterior
+extremity of the sternum; then, covering the anterior
+surface of the trachea, they proceed to terminate, the one
+on the thyroid cartilage, and the other on the hyoid bone.
+The sterno-hyoid is superficial; it covers the sterno-thyroid,
+which, however, projects a little on its outer side.</p>
+
+<p><b>Omo-hyoid.</b>&mdash;This muscle does not exist in the dog or
+cat. It arises, in the horse, from the cervical border of the
+scapula, where it blends with the aponeurosis that envelops
+the subscapularis muscle, but in the pig and the ox it arises
+from the deep surface of the mastoido-humeral muscle. It
+is directed obliquely upwards and inwards, becoming superficial
+at the internal border of the sterno-mastoid, and
+is inserted into the hyoid bone.</p>
+
+<p>The region in which are united the portion of the neck
+which we have just studied and the neighbouring part
+of the thorax&mdash;that is, the breast&mdash;has certainly, in our
+opinion, a form less expressive than the corresponding
+region in man.</p>
+
+<p>In the latter, indeed, the fourchette of the sternum, with
+the hollow which it determines, the heads of the clavicles,
+and the sterno-cleido-mastoid muscles, by the elevations
+which they produce, and the trachea, by the situation which
+it occupies in the inferior part, constitute a whole in which
+are admirably indicated, not only the forms of the organs
+which constitute this region, but also the relations which
+these organs have one with another; and, to a certain extent,
+their respective functions.</p>
+
+<p>In making an exception in the case of the ox, in which a
+fold of skin, the <i>dewlap</i>, which passes from the neck to the
+breast, constitutes an element of form which possesses
+some expressive value; in the horse and in the dog, which
+possess no sternal fourchette and no heads of clavicles, the
+bones and the muscles are found nearly on the same plane.
+This produces a uniformity which is evidently inferior, from<span class="pagenum"><a name="Page_161" id="Page_161">[161]</a></span>
+an &aelig;sthetic point of view, to the modelling of the corresponding
+region of the human body. Such, at least, is our
+impression.</p>
+
+<h5>Suprahyoid Muscles</h5>
+
+<p>As their name indicates, these muscles are found above
+the hyoid bone; amongst those which should arrest our
+attention for a moment are the mylo-hyoid and the digastric.</p>
+
+<p><b>Mylo-hyoid.</b>&mdash;This muscle, forming a sort of fleshy sling
+which contributes in great measure to form the floor
+of the mouth, is situated between the lateral halves of
+the inferior maxillary bone. Arising on each side from the
+internal oblique line of the mandible, its fibres are directed
+towards the median line, to be inserted posteriorly into the
+hyoid bone, and, between this bone and the anterior part of
+the mandible, into a median raphe which unites these latter.</p>
+
+<p><b>Digastric.</b>&mdash;This muscle arises from the styloid process
+of the occipital bone and from the jugular process; it
+thence passes downwards and forwards, and terminates
+variously, in different species. In the ox and the horse it
+terminates in its anterior portion on the internal surface
+of the inferior maxillary bone, close to the chin. But
+in the horse a bundle of fibres is detached from the upper
+portion of the muscle, to be inserted into the recurved
+portion of the jaw. It is to this fasciculus that Bourgelat
+has given the name of &#8216;<i>stylo-maxillary muscle</i>.&#8217;</p>
+
+<p>In the pig, dog, and cat, the digastric differs more from
+the corresponding muscle in man; it is not, as in the latter,
+formed of two parts. The anterior portion only exists.
+This consists of a thick muscular mass, which is inserted into
+the middle of the internal surface of the lower jaw.</p>
+
+<p>In the dog and cat it is clearly recognisable in the superficial
+layer of muscles by the long and thick prominence
+which it produces below the masseter, against the inferior
+border of the mandible (see <a href="#Page_235">pp. 235</a> and <a href="#Page_237">237</a>, the two figures
+showing the myology of the head of the dog).</p>
+
+<p>By its contraction, it draws the lower jaw downwards and
+backwards.</p>
+
+<p><span class="pagenum"><a name="Page_162" id="Page_162">[162]</a></span><b>Panniculus of the Neck.</b>&mdash;This very thin muscle, which
+cannot be recognised on the exterior, calls for little notice.</p>
+
+<p>We shall merely point out that it duplicates the skin of the
+cervical region; but as the latter is only slightly adherent to
+it, the panniculus of this region seems rather destined to
+maintain in position the muscles which it covers than to displace
+the cutaneous covering.</p>
+
+<p>We recall the fact that in man, on the contrary, the muscle
+is very evident at the instant of its contraction, and, for this
+reason, it presents a very great interest with regard to
+external modelling, and it plays an important part in the
+expression of the physiognomy.</p>
+
+<h4><a name="LimbMuscles" id="LimbMuscles"></a>MUSCLES OF THE ANTERIOR LIMBS</h4>
+
+<h5><a name="Shoulders" id="Shoulders"></a>Muscles of the Shoulder</h5>
+
+<p><b>Deltoid</b> (<a href="#Fig068">Fig. 68</a>, 16, 17; <a href="#Fig069">Fig. 69</a>,
+18; <a href="#Fig070">Fig. 70</a>, 24).&mdash;This is
+the first muscle we study in connection with the shoulder in
+human anatomy. Indeed, its wholly superficial position, and
+especially the manner in which it is separated from the surrounding
+muscles, its volume, and its characteristic modelling,
+give it such an importance that, from the didactic point of
+view, there is every indication for commencing with this
+muscle in studying the region to which it belongs. If, in
+regard to quadrupeds, we also commence with it, it is merely
+in deference to the spirit of method, and for the sake of symmetry;
+for it is far from presenting, in the latter, characters
+so distinctive and so clearly defined.</p>
+
+<p>It is necessary to remark, at the outset, that in quadrupeds,
+on account of the absence or slight development of
+the clavicle, the clavicular portion of this muscle is, as we
+have shown, united to bundles of the same kind belonging
+to the sterno-cleido-mastoid and trapezius to form the mastoido-humeral
+(see <a href="#Page_151">p. 151</a>). There exists, therefore, in an
+independent form, the scapular portion only.</p>
+
+<p>It is this latter which, by itself alone, forms the deltoid of
+quadrupeds, a muscle known, in veterinary anatomy, as <i>the
+long abductor of the arm</i>.</p>
+
+<p><span class="pagenum"><a name="Page_163" id="Page_163">[163]</a></span>In the dog and the cat it consists of two parts, one of
+which arises from the spine of the scapula; the other from
+the acromion process. Thence it passes to the crest of the
+humerus, which limits the musculo-spiral groove anteriorly,
+to be attached at a point which is found, as in other quadrupeds,
+to be the homologue of the human deltoid impression,
+or deltoid <span class="lettsymb">V</span>, of the human humerus.</p>
+
+<p>In the ox, in which the acromion process, which is
+very rudimentary, does not attain the level of the glenoid
+cavity, the acromion portion is but slightly marked off
+from that which takes its origin from the spine of the
+scapula.</p>
+
+<p>Still, in the horse, which is completely deprived of an
+acromion process, the deltoid muscle is correspondingly
+divided into two parts, separated from one another by
+superficial interstices, but of which the arrangement differs
+from that of the portions above indicated; one part, the
+posterior, arises above from the superior part of the posterior
+border, and the postero-superior angle of the scapula (exactly
+as if, in man, certain fasciculi of the deltoid took their
+origin from the axillary border and inferior angle of the
+scapula); the other, anterior, arises from the tuberosity of
+the spine of the same bone. The two parts, united inferiorly,
+proceed to be inserted into the deltoid impression
+or infratrochiterian crest of the humerus.</p>
+
+<p>It is necessary to add that the deltoid is inserted into the
+humerus, above the insertion of the mastoido-humeral.</p>
+
+<p>This muscle flexes and abducts the humerus, and also
+rotates it outwards.</p>
+
+<p>With regard to the other muscles of the human shoulder,
+subscapularis, supraspinatus, infraspinatus, teres minor and
+teres major, they are also present in quadrupeds, but in a
+form more elongated, as the scapula has its dimensions more
+extended from below upwards&mdash;that is, from the glenoid
+cavity towards the superior or spinal border.</p>
+
+<p><b>Subscapularis.</b>&mdash;This muscle occupies the subscapular
+fossa, from which it takes its origin, leaving free the superior
+part where the surface is found, to which are attached the
+serratus magnus and the levator anguli scapul&aelig;. It passes<span class="pagenum"><a name="Page_164" id="Page_164">[164]</a></span>
+towards the arm, to be inserted into the small tuberosity
+of the humerus. It is an adductor of the arm.</p>
+
+<p>The subscapularis does not offer any interest from the point
+of view of external form, for it is completely covered by the
+scapula.</p>
+
+<p>We speak of it, however, because we mention it in
+human anatomy, and that it affords us here a new opportunity
+of bringing into prominence the differences which exist
+in connection with the mobility of the shoulder.</p>
+
+<p>We remember that in man, when the arm is abducted, and
+then raised a little above the horizontal, the scapula see-saws,
+is separated, to a certain extent, from the thoracic cage
+inferiorly and externally, and that, on the superficial layer of
+muscles, we are then able to see in the bottom of the armpit,
+at the level of the deep portion of the posterior wall of the
+latter, a small part of the subscapularis muscle.</p>
+
+<p>In the animals with which we are here occupied it is not
+the same; for they are incapable of performing with their
+fore-limbs a movement analogous to that to which we have
+just referred, the humerus in their case being retained in
+contact with the trunk by the muscular masses which
+surround it.</p>
+
+<p><a name="Supraspinatus" id="Supraspinatus"></a><b>Supraspinatus</b> (<a href="#Fig068">Fig. 68</a>, 19; <a
+href="#Fig070">Fig. 70</a>, 25; <a href="#Fig072">Fig. 72</a>, 7).&mdash;This
+muscle, as its name indicates, occupies the supraspinous
+fossa&mdash;that is to say, that which, by reason of the
+direction of the scapula in quadrupeds, is situated in front of
+rather than above the spine. It arises from this fossa; and,
+further, from the external surface of the cartilage which
+prolongs the scapula upwards in solipeds and ruminants. It
+projects more or less beyond the supraspinous fossa in front.</p>
+
+<p>After passing downwards towards the humerus, it is inserted
+into the summit of the great tuberosity or trochiter&mdash;that
+is to say, to a part of this osseous prominence which
+represents the anterior facet of the great tuberosity of the
+human humerus, into which, as we know, the corresponding
+muscle is inserted.</p>
+
+<p>In solipeds and ruminants it is inserted, by a second
+fasciculus, into the small tuberosity.</p>
+
+<p>In the pig and the horse its anterior border is in relation<span class="pagenum"><a name="Page_165" id="Page_165">[165]</a></span>
+with the terminal portion of the sterno-prescapular anterior
+portion of the small or deep pectoral.</p>
+
+<p>The supraspinatus, which in man is completely covered
+by the trapezius, is partly visible in the superficial layer of
+the cat, dog, pig, and horse, in the lower part of the space
+limited by the mastoido-humeral and the trapezius. It is
+crossed by the scapulo-trachelian.</p>
+
+<p>It is, in the ox, completely covered by these muscles, but
+its form, notwithstanding this, is easily discerned by the
+prominence which it produces. When it contracts, the
+supraspinatus muscle carries the humerus into the position
+of extension.</p>
+
+<p><b>Infraspinatus</b> (<a href="#Fig068">Fig. 68</a>, 20; <a href="#Fig072">Fig. 72</a>, 8).&mdash;This muscle,
+which occupies the infraspinous fossa, which, in quadrupeds,
+is situated behind the spine of the scapula, arises from the
+whole extent of this fossa, and in solipeds and ruminants
+encroaches on the cartilage of prolongation. Its fibres are
+directed downwards and forwards, to be inserted into the
+great tuberosity of the humerus&mdash;the trochiter&mdash;below the
+insertion of the supraspinatus.</p>
+
+<p>It is completely covered (ox and horse), or in part only
+(cat and dog), by the portion of the deltoid which arises from
+the spine of the scapula; nevertheless, its presence is revealed
+by the prominence which it produces.</p>
+
+<p>It is an abductor and external rotator of the humerus.</p>
+
+<p>In connection with this muscle, which, as we have just
+pointed out, is less seen in the superficial muscular layer than
+the supraspinatus, we will draw attention to the fact that
+this arrangement is exactly the reverse of that which is found
+in the human shoulder. In this latter it is the supraspinatus
+which is not visible; while, on the contrary, the infraspinatus
+is uncovered in a considerable part of its extent. We
+further notice that it is accompanied by the teres minor, and
+that the teres major, situated inferiorly, forms with these two
+muscles a fleshy mass which, below, ends on the superior
+border of the great dorsal muscle.</p>
+
+<p>In quadrupeds, in which the infraspinatus is so slightly
+visible, the teres major and minor are not found at all in the
+superficial muscular layer.</p>
+
+<p><span class="pagenum"><a name="Page_166" id="Page_166">[166]</a></span>Accordingly, we will say but few words about them.</p>
+
+<div class="figmed"><a name="Fig072" id="Fig072"></a>
+<img src="images/illo189.png" alt="Fig. 72" width="350" height="429" />
+<p class="caption just">Fig. 72.&mdash;Myology of the Horse&mdash;Shoulder and Arm: Left Side,
+External Surface.</p>
+
+<p class="subcaption just">1, Cartilage of prolongation of the scapula; 2, tuberosity of the spine
+of the scapula; 3, superior extremity of the humerus; 4, inferior extremity
+of the humerus; 5, radius; 6, ulna; 7, supraspinatus muscle;
+8, infraspinatus; 9, teres minor; 10, biceps; 11, tendon of the biceps
+passing over the anterior surface of the superior extremity of the humerus;
+12, brachialis anticus; 13, triceps, long head; 14, external head of the
+triceps divided; 15, external head of the triceps reflected, in order to
+expose the anconeus; 16, region normally occupied by the external head of
+the triceps; 17, anconeus.</p></div>
+
+<p><b>Teres Minor</b> (<a href="#Fig072">Fig. 72</a>, 9).&mdash;This muscle, also called in
+veterinary anatomy <i>the short abductor of the arm</i>, arises
+from the posterior border of the scapula (the external
+border in man), and is inserted below the great tuberosity
+of the humerus, between the attachments of the infraspinatus
+and deltoid.</p>
+
+<p>It is covered by the deltoid and the infraspinatus.</p>
+
+<p><b>Teres Major.</b>&mdash;This muscle is known to veterinarians
+as<span class="pagenum"><a name="Page_167" id="Page_167">[167]</a></span>
+<i>the abductor of the arm</i>; it arises from the postero-superior
+angle of the scapula (the inferior angle of the human
+scapula), from which it passes to be inserted into the internal
+surface of the humerus.</p>
+
+<p>It is covered by the latissimus dorsi and the posterior
+muscular mass of the arm.</p>
+
+<p>In brief, for the better understanding of the relations of the
+teres major and minor muscles in quadrupeds, we may fancy
+the corresponding muscles in man modified in the following
+manner: The infraspinatus, thicker, covering the teres minor;
+latissimus dorsi, more extended in its superior part, covering
+a large proportion of the teres major. As to the relations
+of the teres minor with the deltoid, they exist in man,
+seeing, in this case, the same muscle is, in its external
+portion, covered by this latter. With regard to the relations
+of the teres major with the posterior muscular mass of the
+arm, they also exist in man, since the external surface of
+this muscle is covered by the triceps.</p>
+
+<p>These modifications are sufficient to render the small and
+large teres muscles completely invisible in the superficial
+layer.</p>
+
+<p>The muscles of the shoulder which we have just been
+studying fulfil, with regard to the articulation which they
+surround, the function of active ligaments. This r&ocirc;le
+is made necessary by the laxity of the scapulo-humeral
+capsule&mdash;a laxity which renders it incapable by itself of
+maintaining the bones in contact at this joint.</p>
+
+<p>The same condition exists in man.</p>
+
+<p><b>Panniculus Muscle of the Shoulder.</b>&mdash;This thin muscle
+covers, as its name implies, the region of the shoulder, and
+is the continuation forward of the panniculus muscle of the
+trunk.</p>
+
+<p>It arises, by its superior part, from the region of the
+withers and from the superior cervical ligament; thence its
+fibres descend directly towards the elbow, to terminate at
+the level of the region of the forearm.</p>
+
+<p>The muscle is not found in the pig or in the carnivora.</p>
+
+<p class="pagenum"><a name="Page_168" id="Page_168">[168]</a></p>
+
+<h5>Muscles of the Arm</h5>
+
+<p>We should remember, at the outset, that in man the
+muscles of the arm are divided into two groups: one
+anterior, which contains the biceps, brachialis anticus, and
+the coraco-brachialis; the other, posterior, which is constituted
+by a single muscle, the triceps.</p>
+
+<p>In animals, we find them in the same number and arranged
+in analogous fashion&mdash;that is to say, in two groups&mdash;with
+respect to the bone of the arm. But then we find that they
+have undergone a transformation with regard to their length,
+and it is the change of general aspect which results from this
+modification that we proceed to examine.</p>
+
+<p>We know that in quadrupeds, and especially in the
+domestic animals, the humerus is relatively short in proportion
+to the forearm. We have already seen, in dealing with
+the bones, that whilst in the human species the humerus
+is longer than the forearm, in the dog and cat these two
+segments of the fore-limb are of equal length, and that the
+humerus of the horse is, on the contrary, much shorter.
+Now, let us suppose the human humerus to be shorter than
+it is in reality; the anterior muscles undergoing, very naturally,
+the same reduction, will be uncovered only slightly by
+those above&mdash;the deltoid and the great pectoral&mdash;or will
+remain completely hidden by them. Thus would be found
+realized the disposition which we meet with in quadrupeds
+of the muscles of this region.</p>
+
+<p>With regard to the posterior muscular mass of the arm, it
+does not undergo the same change. The muscle which
+constitutes it&mdash;the triceps cubiti&mdash;occupies, on the contrary,
+a greater area. Let us suppose, further&mdash;for it is
+the best method of comprehending the homologies which
+now occupy our attention&mdash;the humerus of man to be
+shortened as before, and directed downwards and backwards
+(as in quadrupeds), this bone would form an acute angle
+with the axillary border of the scapula. Let us suppose
+also that the long portion of the triceps, instead of arising
+solely from the superior part of this axillary border, is
+attached to the whole length of the latter, and that the<span class="pagenum"><a name="Page_169" id="Page_169">[169]</a></span>
+triceps fills the whole interior of the angle formed by the arm
+and the shoulder. We then shall have an idea of what the
+triceps is in quadrupeds. It is necessary to add that the
+general resemblance would be still more complete if the arm
+were firmly supported by the side of the thorax, because in
+quadrupeds it occupies an analogous position, determined
+by the arrangement of the muscles which, proceeding from
+the trunk and neck, are attached to it.</p>
+
+<h5>Anterior Region</h5>
+
+<p><b>Biceps Cubiti</b> (<a href="#Fig068">Fig. 68</a>, 21; <a href="#Fig072">Fig. 72</a>, 10, 11).&mdash;This
+muscle, also called <i>the long flexor of the forearm</i>, does
+not merit the name except by its analogy with the corresponding
+muscle in man. Indeed, in the domestic animals
+it is not divided into two parts; it is represented by a
+single fasciculus, long and fusiform, situated on the front of
+the humerus, and directed obliquely downwards and backwards,
+as the latter, on its part, is also inclined.</p>
+
+<p>It arises above from a tubercle at the base of the coracoid
+process, which surmounts the glenoid cavity of the scapula.
+Its tendon, which is highly developed in the solipeds, occupies
+the bicipital groove. We remember that in these latter
+the groove in question is divided into two channels by a
+median prominence.</p>
+
+<p>The tendon in which the muscle ends is inserted into a
+tuberosity, situated on the internal surface of the superior
+extremity of the radius&mdash;the bicipital tuberosity. In the pig,
+the cat, and the dog, there is detached from the tendon to
+which we have just referred a fasciculus of the same nature,
+which, after having wound round the radius, is inserted into
+the internal surface of the ulna, towards the base of the
+olecranon process. From the inferior part of the muscle
+arises a fibrous band, comparable to the aponeurotic expansion
+of the human biceps; but, instead of passing downwards
+and inwards, as does the latter, it terminates on
+the muscular mass which constitutes the antero-external
+part of the forearm.</p>
+
+<p>The biceps is not seen in the superficial layer, except in
+the dog and cat (in which the humerus is, in fact, proportionately<span class="pagenum"><a name="Page_170" id="Page_170">[170]</a></span>
+long); and even in them only to the slightest
+extent. It is covered partly in these latter, and completely
+in other animals, by the great pectoral and the inferior
+portion of the mastoido-humeral&mdash;that is to say, that part
+of the latter which represents the whole of the clavicular
+fibres of the human deltoid.</p>
+
+<p>The biceps is a flexor of the forearm on the arm. It also
+contributes to the movement of extension of the humerus.</p>
+
+<p><b>Brachialis Anticus</b> (<a href="#Fig068">Fig. 68</a>, 22; <a href="#Fig069">Fig. 69</a>, 19; <a href="#Fig070">Fig. 70</a>,
+27; <a href="#Fig072">Fig. 72</a>, 12).&mdash;In veterinary anatomy further designated
+as <i>the short flexor of the forearm</i>, this muscle, which is
+thick, occupies the musculo-spiral groove, and arises from
+it, reaching upwards to just below the head of the humerus.
+But it does not, as in man, extend to the internal surface of
+the bone.</p>
+
+<p>Situated on the outside of the biceps, it is directed towards
+the forearm, and terminates by a flattened tendon, which,
+dividing into two slips, passes below the bicipital tuberosity,
+on the internal surface of the radius, into which one of
+these slips is inserted, while the other proceeds to terminate
+on the ulna.</p>
+
+<p>The inferior half of this muscle is visible on the superficial
+layer, in the space limited posteriorly by the triceps brachialis,
+and below by the muscles of the forearm, which correspond
+to the external muscles of the human forearm, and in
+front by the great pectoral and the mastoido-humeral. It
+is in the upper part of the interspace which separates these
+latter from the brachialis anticus that the deltoid insinuates
+itself to proceed to its insertion into the humerus.</p>
+
+<p>These relations precisely recall those which we meet with
+when we examine the external surface of the human arm,
+with this difference, however&mdash;that in the latter the anterior
+brachialis anticus is extensively related, in front, to the biceps.
+However, in animals it is not absolutely the same, since,
+as we have shown above, the biceps is covered, more or
+less completely, by the mastoido-humeral and the great
+pectoral.</p>
+
+<p>The brachialis anticus flexes the forearm on the arm.</p>
+
+<p><b>Coraco-brachialis.</b>&mdash;In man this muscle, which occupies<span class="pagenum"><a name="Page_171" id="Page_171">[171]</a></span>
+the superior half, or third, of the internal surface of
+the humerus, is visible only when the arm is abducted,
+and then especially when it approaches the vertical position;
+indeed, it is only in this attitude that the region
+which it occupies is accessible to view.</p>
+
+<p>But an analogous attitude not being possible in domestic
+animals, in which the arm is fixed along the corresponding
+parts of the trunk, the result is that the coraco-brachialis is
+always covered, and that, consequently, it presents nothing
+of interest from our point of view. We speak of it, then,
+merely in order to complete the series of the muscles of the
+anterior surface of the arm, among which we rank it, in spite
+of the fact that in veterinary anatomy it is described as a
+muscle of the shoulder.</p>
+
+<p>It arises above from the coracoid process, and thence
+passes downwards towards the internal surface of the
+humerus into which it is inserted, more or less high up,
+according to the species. The coraco-brachialis is an
+adductor of the arm.</p>
+
+<h5>Posterior Region</h5>
+
+<p><b>Triceps Cubiti</b> (<a href="#Fig068">Fig. 68</a>, 23, 24; <a href="#Fig069">Fig. 69</a>, 20, 21;
+<a href="#Fig070">Fig. 70</a>, 28, 29; <a href="#Fig072">Fig. 72</a>, 13, 14, 15, 16).&mdash;This muscle, which
+is voluminous in the quadrupeds with which we are here concerned,
+fits more or less completely the angular space between
+the scapula and the humerus. Its bulk forms a thick
+prominence, which surmounts the elbow and the forearm.</p>
+
+<p>We should say, with regard to this mass, that if the deltoid
+does not constitute in quadrupeds a prominence sufficient to
+remind one of that which this muscle produces in man,
+the triceps, in producing an analogous elevation, seems to
+replace in the general form of the body the relief which the
+deltoid is incapable of producing.</p>
+
+<p>The triceps is divided into three portions, which, as in
+man, have the names middle, or long head; external and
+internal heads. But that which renders the nomenclature a
+little complicated is that veterinary anatomists have given
+other names to these three parts: that of <i>great extensor of
+the forearm</i> (caput magnum) to the long head; <i>the short</i><span class="pagenum"><a name="Page_172" id="Page_172">[172]</a></span>
+<i>extensor of the forearm</i> (caput parvum) to the external head;
+and of <i>medium extensor of the forearm</i> (caput medium) to the
+internal.<a name="FNanchor_24_24" id="FNanchor_24_24"></a><a href="#Footnote_24_24" class="fnanchor">[24]</a></p>
+
+<div class="footnote"><p><a name="Footnote_24_24" id="Footnote_24_24"></a><a href="#FNanchor_24_24"><span
+class="label">[24]</span></a> Other names given by certain authors to the parts of this muscle
+which we have just enumerated still further complicate this nomenclature.
+</p><p>
+The long head is further designated by them under the names of the
+<i>long</i> or <i>great anconeus</i>; the <i>external head</i> under those of <i>external anconeus</i>,
+or <i>lateral</i> or <i>short anconeus</i>; whilst the internal head becomes the <i>internal
+anconeus</i>, or <i>median</i>.</p></div>
+
+<p>It is more especially the long portion and the external
+head which, being visible on the external surface of the arm,
+contribute to the external form.</p>
+
+<p>The long portion, which is triangular in shape and of
+considerable development, arises in the cat and the dog from
+the inferior half or two-thirds of the posterior border of the
+scapula (axillary border); from the whole extent of that
+border as far as the superior posterior angle in the pig, the
+ox, and the horse; it then passes downwards towards the
+articulation of the elbow, to terminate in a tendon which is
+inserted into the olecranon process. The portion of this
+muscle which is next the scapula is covered by the deltoid.</p>
+
+<p>The external head, situated below the long portion, is
+directed obliquely downwards and backwards. It arises
+from the curved crest which, from the deltoid impression
+of the humerus, is directed upward to meet the articular head
+of the same bone. This crest limiting the musculo-spiral
+groove superiorly, and the brachialis anticus arising from the
+whole extent of this groove, the result is that at this level
+the external head is in relation with the brachialis anticus.
+From this origin it is directed towards the elbow, to be
+inserted into the olecranon, either directly or by the medium
+of the tendon of the long portion. The part of this muscle
+which arises from the humerus is covered by the deltoid.</p>
+
+<p>As for the internal head (<a href="#Fig076">Fig. 76</a>, 4), which, in the superficial
+layer, is only visible in its inferior part, on the internal
+aspect of the arm in those animals in which the elbow is
+free of the lateral wall of the thorax (the dog and the cat,
+for example), it arises from the internal surface of the
+humerus, and thence proceeds to be inserted into the olecranon.</p>
+
+<p><span class="pagenum"><a name="Page_173" id="Page_173">[173]</a></span>The triceps extends the forearm on the arm.</p>
+
+<p>A fourth muscle exists, which veterinary anatomists
+include in the study of the three portions of the triceps which
+we have just been discussing, in giving it the name of
+<i>small extensor of the forearm</i>. But, as this muscle is no other
+than the <a href="#Anconeus">anconeus</a>, and as, in human anatomy, we describe
+the latter, according to custom, in connection with
+the forearm, it is when on the subject of the latter that we
+will concern ourselves with it. This grouping of muscles
+cannot fail to give greater clearness to the description of the
+muscles of these regions.</p>
+
+<p><b>The Supplemental or Accessory Muscle of the Latissimus
+Dorsi</b> (<a href="#Fig076">Fig. 76</a>, 2; <a href="#Fig077">Fig. 77</a>, 1).&mdash;Because of the
+relations, to which we have already referred (see <a href="#Page_142">p. 142</a>),
+of this muscle with the triceps cubiti, its description very
+naturally follows that of the latter.</p>
+
+<p>Indeed, this supplementary muscle of the great dorsal is
+further designated in zoological anatomy under the name
+of <i>long extensor of the forearm</i>; and this name indicates that
+its study may be united to that of the triceps.</p>
+
+<p>Situated on the internal surface of the arm, it arises
+from the external aspect of the tendon of the latissimus
+dorsi; it is very highly developed in the horse, in which it
+also arises from the posterior border (axillary) of the
+scapula; then, covering in part the internal head of the
+triceps and also the long portion, on the superior border of
+which it is folded, it proceeds to be inserted into the olecranon
+process and the anti-brachial aponeurosis.</p>
+
+<p>It extends the forearm on the arm. Further, it makes
+tense the aponeurosis into which it is inserted; this explains
+the name of <i>tensor of the fascia of the forearm</i>, which is sometimes
+given to it.</p>
+
+<p>It seems to us interesting to add that, abnormally, we
+sometimes find in man an analogue of this muscle. It is
+given off from the latissimus dorsi, near the insertion of the
+latter into the humerus; it accompanies the long head of
+the triceps and becomes fused with it. Sometimes it is
+inserted into the olecranon process, at other times into the
+antibrachial aponeurosis or the epitrochlea. It is on account<span class="pagenum"><a name="Page_174" id="Page_174">[174]</a></span>
+of its insertion into the last-mentioned, in some cases, that
+it is also designated by the name of <i>dorso-epitrochlear</i>
+muscle.<a name="FNanchor_25_25" id="FNanchor_25_25"></a><a href="#Footnote_25_25" class="fnanchor">[25]</a></p>
+
+<div class="footnote"><p><a name="Footnote_25_25" id="Footnote_25_25"></a><a href="#FNanchor_25_25"><span class="label">[25]</span></a>
+L. Testut, &#8216;Anomalies musculaires chez l&#8217;homme expliqu&eacute;es par
+l&#8217;anatomie compar&eacute;e,&#8217; Paris, 1884, p. 118. A. F. Le Double, &#8216;Trait&eacute;
+des variations du syst&egrave;me musculaire de l&#8217;homme et de leur signification
+au point de vue de l&#8217;anthropologie zoologique,&#8217; Paris, 1897, t. i., p. 203.
+&Eacute;douard Cuyer, &#8216;Anomalies musculaires&#8217; (<i>Bulletins de la Soci&eacute;t&eacute; Anthropologique</i>,
+Paris, 1893).</p></div>
+
+<h5>Muscles of the Forearm</h5>
+
+<p>Before commencing the special examination of each of
+the muscles of this region, it is absolutely indispensable to
+consider their general arrangement, and to determine very
+clearly how we should study them. We are too well convinced
+of the importance of this preliminary examination
+to dismiss it without entering rather fully into it. Indeed,
+the region on the myological study of which we are now
+entering is, unquestionably, one of the most complicated
+with which we have to deal. We know besides, in regard
+to the study of the forearm in man, how much a definite
+method is necessary in order that the arrangement of the
+muscles of this region be fixed in the memory, and that we
+are unable to obtain this result otherwise than by grouping
+the twenty muscles which constitute it in clearly defined
+regions.</p>
+
+<p>We also know that these muscles are first studied with the
+forearm in the position of supination, and that it is only
+when they are well known after having considered them in
+this position that we are able to analyze and comprehend
+their forms when it is in pronation.</p>
+
+<p>Now, as we have pointed out in the section on osteology
+(see <a href="#Page_34">p. 34</a>), the forearm in quadrupeds is always in the
+position of pronation. Should we, then, in order to maintain
+the symmetry with human anatomy, first study the
+forearm in the position of supination? Evidently not.
+Besides the fact that this would in some cases be impossible
+since&mdash;as in the horse, for example&mdash;the radius and ulna<span class="pagenum"><a name="Page_175" id="Page_175">[175]</a></span>
+are fused together, we should not gain any advantage; this
+position being never completely realizable even in those
+quadrupeds which have the radius relatively movable&mdash;as,
+for example, in the cat.</p>
+
+<p>Accordingly, it is pronation which here, in connection
+with animals, becomes the standard attitude from the point
+of view of description. This is why, supposing that the
+reader knows well the muscles of the human forearm in the
+position of supination, we should recall what is the general
+arrangement occupied by these muscles when it is in pronation.</p>
+
+<p>The fore-limb, being viewed on its anterior surface, presents
+above the anterior aspect of the region of the elbow;
+but below, it is the posterior surface of the wrist which is
+seen. Consequently, in the superior part, we see the external
+and anterior muscles limiting the hollow in front of
+the elbow; interiorly are found the posterior muscles.</p>
+
+<p>The long supinator, passing obliquely downwards and
+inwards, divides, in fact, the forearm into two parts: one
+supero-internal, the other infero-external. In the first we
+see, but to an extent less and less considerable, the pronator
+teres, the flexor carpi radialis, the palmaris longus,
+and the flexor ulnaris; as to the flexors of the digits, on
+account of the rotation of the radius, they are only visible on
+the opposite surface&mdash;that is to say, on the surface of the
+wrist, which is now posterior. In the second part we see the
+two radial extensors, the common extensor of the fingers,
+the proper extensor of the little finger, and the ulnar extensor
+which, inferiorly, remains behind, by reason of the position
+of the ulna being unchanged, whilst the anconeus is wholly
+posterior, since the direction of the elbow is not modified.
+We also find, in this region, the long abductor of the thumb,
+the short extensor of the thumb, the long extensor of the
+thumb, and the special extensor of the index-finger, in the
+region where these deep muscles become superficial.</p>
+
+<p>So that, to summarize, the external and posterior muscles
+occupy the anterior and external regions of the forearm,
+whilst the anterior muscles occupy rather the internal and
+posterior. It is in regarding them after this manner&mdash;that<span class="pagenum"><a name="Page_176" id="Page_176">[176]</a></span>
+is to say, arranged in these two regions&mdash;that we proceed
+to study these muscles in quadrupeds.</p>
+
+<h5>Anterior and External Region</h5>
+
+<p><b>Supinator Longus.</b>&mdash;We know that this muscle, which
+is especially a flexor of the forearm on the arm, plays, notwithstanding
+the name which has been given it, a part of
+but little importance in the movement of supination.</p>
+
+<p>It acts slightly, however, as a supinator, for, being very
+oblique downwards and inwards at the time of pronation, it
+is able, while tending to resume its vertical direction, to
+carry the radius outwards; it places, in fact, the forearm
+in a position midway between pronation and supination.</p>
+
+<p>We have just recalled these details, in order that it may
+be more easy to understand why it does not exist in animals
+in which the radius and ulna are fused together (horse, ox);
+and why, on the other hand, we find traces of it in the cat
+and the dog, in which the radius&mdash;to a slight extent, it is
+true&mdash;is able to rotate on the ulna. This displacement
+being a little more considerable in the felide, the long supinator
+is a little further developed than it is in the canine
+species; but, notwithstanding, it is only rudimentary.</p>
+
+<p>The long supinator arises, above, from the external border
+of the humerus; thence, in the form of a very narrow
+fleshy band, it passes obliquely downwards and inwards,
+to be inserted into the inferior part of the internal surface
+of the radius.</p>
+
+<p>It assists in turning the radius outwards and placing it
+in front of the ulna, the movement of supination being
+capable of being but little further extended.</p>
+
+<p><b>First and Second External Radial Muscles</b>: <i>Extensor
+carpi radialis longior and brevior</i> (<a href="#Fig073">Fig. 73</a>, 8; <a href="#Fig074">Fig. 74</a>, 8, 9;
+<a href="#Fig075">Fig. 75</a>, 8, 9).&mdash;Fused together, these muscles form by their
+union what veterinary anatomists call <i>the anterior extensor of
+the metacarpus</i>. But we should add that these two muscles
+are united so much the more intimately as we examine
+them in passing successively from the cat to the dog, pig,
+ox, and horse. Thus, in the cat they are often distinct; in<span class="pagenum"><a name="Page_177" id="Page_177">[177]</a></span>
+the dog, they unite only at the level of the middle third of
+the radius, and interiorly they have two tendons; in the
+pig, the ox, and the horse they are completely united, and
+there exists but a single tendon.</p>
+
+<p>The <i>anterior extensor of the metacarpus</i>, which is situated
+behind the long supinator when the latter exists, occupies
+the external aspect of the forearm; its well-defined form
+absolutely recalls the prominence on the superior part of the
+external margin of the human forearm.</p>
+
+<p>It arises superiorly from the portion of the external border
+of the humerus which is situated above the epicondyle and
+behind the musculo-spiral groove. Its fleshy mass appears in
+the angular space bounded by the brachialis anticus and the
+triceps. The superior portion is covered by the external head
+of the triceps; yet, in the dog, the superior portion of its
+humeral attachment is the only part so covered. This muscle
+is directed forward and downwards; it is also inclined a little
+inwards in such manner as to proceed to occupy the anterior
+aspect of the forearm.</p>
+
+<p>Its fleshy belly is narrowed below, and, towards the
+inferior part of the forearm, is continued by a tendinous
+portion which is situated on the anterior surface of the
+carpus, after having traversed the median groove of the
+inferior extremity of the radius.</p>
+
+<p>In the cat and the dog, in which the union of the two
+radial extensors is incomplete, the two tendons are
+inserted into the front of the base of the second and third
+metacarpal bones; consequently, as in man, into the metacarpals
+of the index and middle fingers.</p>
+
+<p>In the ox, the tendon, which is single, is inserted into the
+internal and anterior half of the superior extremity of the
+principal metacarpal.</p>
+
+<p>In the pig, this tendon is attached to the base of the large
+internal metacarpal.</p>
+
+<p>In the horse, the corresponding tendon is attached to a
+tubercle which is situated on the anterior surface of the base
+of the principal metacarpal, a little internal to the median
+plane of the latter.</p>
+
+<p class="pagenum"><a name="Page_178" id="Page_178">[178]</a></p>
+
+<div class="figmed"><a name="Fig073" id="Fig073"></a>
+<img src="images/illo201.png" alt="Fig. 73" width="350" height="473" />
+<p class="caption just">Fig. 73.&mdash;Myology of the Dog: Left Anterior Limb, External
+Aspect.</p>
+
+<p class="subcaption just">1, Mastoido-humeralis; 2, biceps; 3, brachialis anticus; 4, triceps, long
+portion; 5, triceps, external head; 6, olecranon process; 7, epicondyle;
+8, radialis muscles (anterior extensor of the metacarpus); 9, extensor
+communis digitorum (anterior extensor of the phalanges); 10, extensor
+minimi digiti (lateral extensor of the phalanges, or common extensor of
+the three external digits); 11, posterior ulnar (external flexor of the metacarpus);
+12, pisiform bone; 13, anconeus; 14, extensor ossis metacarpi
+pollicis and extensor primi internodii pollicis (oblique extensor of the
+metacarpus); 15, radius; 16, anterior ulnar (oblique flexor of the metacarpus);
+17, external border of the hypothenar eminence (abductor of
+the little finger).</p></div>
+
+<p>In order to properly understand and remember the respective<span class="pagenum"><a name="Page_179" id="Page_179">[179]</a></span>
+positions occupied by these inferior insertions, it
+must be remembered that the human forearm being in the
+position of pronation, the tendons of the radials are attached
+to the bases of the metacarpals nearest to the thumb&mdash;that
+is to say, those occupying an internal position as regards
+the fourth and fifth metacarpals.</p>
+
+<p>As its name indicates, this muscle extends the metacarpus.
+Consequently it is, in the horse, an extensor of the canon-bone.</p>
+
+<p>It is also an adductor of the hand in those animals (cat,
+dog) in which the radio-carpal articulation, analogous
+in form to the corresponding articulation in man, permits
+lateral movements of the hand on the forearm. The union
+of the fleshy bodies of the two radials is sometimes found
+in the human species.</p>
+
+<p><b>Supinator Brevis.</b>&mdash;As in the case of the long supinator,
+the short supinator is found only in animals in which the
+radius can be rotated to a greater or less extent around
+the ulna; therefore this muscle is not found in the pig, the
+ox, or the horse; but it forms part of the forearm of the cat
+and the dog.</p>
+
+<p>Deeply situated at the region of the elbow, the short
+supinator has little interest for us. All that we will say of
+it is that it goes from the external part of the inferior extremity
+of the humerus to the superior part of the radius;
+and that it is, in carnivora, the essential agent in the production
+of the movement of supination.</p>
+
+<p><b>Extensor Communis Digitorum</b> (<a href="#Fig073">Fig. 73</a>, 9, 10, 11;
+<a href="#Fig074">Fig. 74</a>, 10, 11, 12).&mdash;Also named in veterinary anatomy
+the <i>anterior extensor of the phalanges</i>, this muscle is situated
+external to and behind the anterior extensor of the metacarpus
+already described.</p>
+
+<p class="pagenum"><a name="Page_180" id="Page_180">[180]</a></p>
+
+<div class="figmed"><a name="Fig074" id="Fig074"></a>
+<img src="images/illo203.png" alt="Fig. 74" width="300" height="528" />
+<p class="caption just">Fig. 74.&mdash;Myology of the Ox: Left Anterior
+Limb, External Aspect.</p>
+
+<p class="subcaption just">1, Mastoido-humeralis;
+2, pectoralis
+major; 3,
+deltoid; 4, brachialis
+anticus; 5,
+triceps; 6, triceps,
+external
+head; 7, olecranon;
+8, radial extensors
+(anterior
+extensor of the
+metacarpus); 9,
+insertion of the
+tendon of the anterior extensor
+of the metacarpus
+to the tubercle of the superior
+extremity of the principal
+metacarpal; 10, 11,
+extensor communis digitorum
+(10, proper extensor
+of the inner digits; 11,
+common extensor of the
+two digits); 12, tendon of
+the common extensor of
+the two digits; 13, band
+of reinforcement from the
+suspensory ligament of the fetlock; 14, external tuberosity of the superior
+extremity of the radius; 15, extensor minimi digiti (proper extensor
+of the external digit); 16, tendon of the proper extensor of the external
+digit; 17, posterior ulnar (external flexor of the metacarpus); 18, pisiform;
+19, extensor ossis metacarpi pollicis and extensor primi internodii pollicis
+(oblique extensor of the metacarpus); 20, ulnar portion of the deep flexor
+of the toes; 21, tendon of the superficial flexor of the toes (superficial
+flexor of the phalanges); 22, tendon of the deep flexor of the toes (deep
+flexor of the phalanges); 23, suspensory ligament of the fetlock.</p></div>
+
+<p>In the human being, the common extensor of the fingers
+springs, in its superior part, from the bottom of a depression,
+situated on the outer side of and behind the elbow, and limited
+in front by the muscular prominence which the long supinator
+and the first radial extensor form at that level. At the
+bottom of this hollow or fossette is found the epicondyle,
+which gives origin, amongst other muscles, to the common<span class="pagenum"><a name="Page_181" id="Page_181">[181]</a></span>
+extensor of the fingers. It is necessary to add that it is most
+prominently visible during supination, and that it tends to
+be effaced during pronation.</p>
+
+<p>An analogous arrangement is met with in animals. But
+the muscular prominence is formed by the united radial
+extensors, and the fossette, because of the permanent pronation
+of the forearm, is scarcely recognisable. Likewise,
+with regard to the dog, we may say that it does not exist,
+on account of the prominence which the epicondyle forms
+in that animal (<a href="#Fig073">Fig. 73</a>, 7).</p>
+
+<p>In connection with this prominence of the epicondyle,
+it is interesting to add that this detail recalls the relief
+which the same process produces on the external aspect of
+the human elbow when the forearm is flexed on the arm.
+We know that, in this case, the epicondyle is exposed,
+because the muscles which mask it in supination (long supinator
+and long radial extensor) are displaced and set it free
+during flexion. But, in the dog, as in other quadrupeds
+besides, the forearm is, in the normal state, flexed on the
+arm; the latter being oblique downwards and backwards,
+and the former being vertical. Further, the epicondyle is
+well developed.</p>
+
+<p>The muscle with which we are now occupied, long and
+vertical in direction, arises from the inferior part of the
+external border of the humerus (there it is covered by
+the anterior extensor of the metacarpus, from which
+it is freed a little lower down) and from the external
+and superior tuberosity of the radius. In the carnivora,
+it arises from the epicondyle. Its fleshy body is fusiform
+in shape, becomes tendinous in the lower half of the forearm,
+and then divides into a number of slips, varying in
+number according to the species; this division is correlated
+to that of the hand&mdash;that is to say, with the number of the
+digits. Before reaching this latter, the common extensor
+of the digits passes through the most external groove on
+the anterior surface of the inferior extremity of the
+radius.</p>
+
+<p class="pagenum"><a name="Page_182" id="Page_182">[182]</a></p>
+
+<div class="figmed"><a name="Fig075" id="Fig075"></a>
+<img src="images/illo205.png" alt="Fig. 75" width="275" height="566" />
+<p class="caption just">Fig. 75.&mdash;Myology of the Horse:
+Left Anterior Limb, External
+Aspect.</p>
+
+<p class="subcaption just">1, Mastoido-humeral; 2,
+pectoralis major; 3, deltoid;
+4, brachialis anticus; 5, triceps,
+long head; 6, triceps,
+external head; 7, olecranon;
+8, radial extensors (anterior
+extensor of the metacarpus);
+9, insertion of the tendon of
+the anterior extensor of the
+metacarpus into the tubercle
+of the superior extremity of
+the principal metacarpal; 10,
+extensor communis digitorum
+(anterior extensor of
+the phalanges); 11, tendon
+of the anterior extensor of the
+phalanges; 12, reinforcing
+band arising from the suspensory
+ligament of the fetlock;
+13, external tuberosity of the
+superior extremity of the
+radius; 14, extensor minimi
+digiti (lateral extensor of the
+phalanges); 15, tendon of the
+lateral extensor of the phalanges; 16, fibrous band which this latter
+receives from the tendon of the anterior extensor of the phalanges; 17,
+fibrous band which the same tendon receives from the carpal region;
+18, posterior ulnar (external flexor of the metacarpus); 19, pisiform;
+20, extensor ossis metacarpi pollicis and extensor primi internodii pollicis
+(oblique flexor of the metacarpus); 21, ulnar portion of the deep flexor of
+the digits; 22, flexor digitorum profundus; 23, 23, tendon of the flexor
+digitorum sublimis (superficial flexor of the phalanges); 24, 24, tendon
+of the flexor digitorum profundus (deep flexor of the phalanges); 25, sesamoid
+prominence; 26, suspensory ligament of the fetlock; 27, external
+rudimentary metacarpal.</p></div>
+
+<p>In the cat and the dog, the four tendons which result
+from the division of the principal tendon go to the four last<span class="pagenum"><a name="Page_183" id="Page_183">[183]</a></span>
+digits, and each of them is inserted, as in the human species,
+to the second and third phalanges.</p>
+
+<p>In the pig, the anterior extensor of the phalanges is rather
+complicated in its arrangement. Its fleshy body is divided
+into four bundles terminated by tendons, which in turn
+divide and join certain digits; whence the special names
+given to each of these fasciculi, commencing with the most
+internal, of: <i>proper extensor of the great inner toe</i>; <i>common
+extensor of the two inner toes</i>; <i>common extensor of the two
+outer toes</i>; and <i>proper extensor of the great outer toe</i>.</p>
+
+<p>In the ox, the same muscle is divided into two bundles:
+the internal proceeds to the internal toe, the external is
+common to the two toes.</p>
+
+<p>In the horse, the tendon of the anterior extensor of the
+phalanges is divided into two parts of unequal bulk. The
+smaller of these tendinous slips, which is the more external,
+unites at the level of the superior part of the metacarpus
+with the tendon of the muscle which we are about to
+study in the following paragraph (<a href="#Fig075">Fig. 75</a>, 16). The larger,
+after having reached the anterior surface of the digit, is
+attached to the anterior aspect of the first and second
+phalanges, and then forms a terminal expansion which is
+inserted into the pyramidal eminence of the third.</p>
+
+<p>At the level of the first phalanx this tendon receives on
+each of its lateral aspects a strengthening band, which
+proceeds from the terminal extremity of <i>the suspensory
+ligament of the fetlock</i>,<a name="FNanchor_26_26" id="FNanchor_26_26"></a><a
+href="#Footnote_26_26" class="fnanchor">[26]</a> and crosses obliquely downwards
+and forwards over the surface of the first phalanx to join
+the extensor tendon (<a href="#Fig075">Fig. 75</a>, 12).</p>
+
+<div class="footnote"><p><a name="Footnote_26_26" id="Footnote_26_26"></a><a href="#FNanchor_26_26"><span class="label">[26]</span></a>
+See <a href="#Page_200">p. 200</a> for a description of this ligament.</p></div>
+
+<p>A similar arrangement is found in the ox.</p>
+
+<p>This band is noticeable under the skin which covers the
+lateral aspects of the ham.</p>
+
+<p>As the name indicates, this muscle extends the phalanges,
+one upon the other. It also contributes to the extension
+of the hand, as a whole, on the forearm.</p>
+
+<p><b>Extensor Minimi Digiti</b> (<a href="#Fig073">Fig. 73</a>, 10; <a href="#Fig074">Fig. 74</a>, 15, 16;
+<a href="#Fig075">Fig. 75</a>, 14, 15).&mdash;This muscle, <i>the lateral extensor of the
+phalanges</i> of veterinary anatomy, situated on the external<span class="pagenum"><a name="Page_184" id="Page_184">[184]</a></span>
+surface of the forearm, behind the common extensor
+of the digits, arises, as a rule, from the epicondyle
+(dog, cat), or from the external surface of the superior
+extremity of the radius (horse). The tendon succeeding
+to the fleshy body appears towards the lower third
+of the forearm, and at the level of the wrist lies in a
+groove analogous to that which in man is hollowed out
+for the passage of the corresponding tendon at the level
+of the inferior radio-ulnar articulation. This groove corresponds
+to the same articulation in animals in which the
+ulna is well developed, such as the dog and the cat; but
+it belongs to the radius when the inferior extremity of the
+ulna does not exist&mdash;for example, in the horse. Indeed,
+in this animal the groove in question is found on the external
+surface of the carpal extremity of the radius.</p>
+
+<p>In the dog, the tendon is divided into three parts, which,
+crossing obliquely the tendons of the common extensor of
+the digits, pass to the three external digits, to be inserted
+by blending with the corresponding tendons of the latter
+into the third phalanges of those digits.</p>
+
+<p>Thus is explained the name of <i>common extensor of the three
+external digits</i> which is sometimes given to this muscle.</p>
+
+<p>In the cat, there is a fourth tendon, which passes to the
+index-finger, so that the name <i>common extensor of the four
+external digits</i> is in this case legitimate, and the lateral extensor
+of the phalanges is also a common extensor, as is
+the anterior extensor of the phalanges, or common extensor
+of the digits.</p>
+
+<p>In the pig, the tendon, which is single, is inserted into
+the external digit, for which reason it has received the
+name of the <i>proper extensor of the small external digit</i>. This
+muscle is, then, really the homologue of that which exists
+in the human species.</p>
+
+<p>In the ox, it is called the <i>proper extensor of the external
+digit</i>; it is as thick as the common extensor.</p>
+
+<p>Finally, in the horse, the muscle is little developed. Its
+fleshy body, thin and flattened from before backwards,
+becomes distinctly visible only below the middle of the
+forearm. Above, it is enclosed in a limited space, bounded<span class="pagenum"><a name="Page_185" id="Page_185">[185]</a></span>
+in front by the common extensor of the digits, and behind
+by the posterior ulnar; there these two muscles approach
+each other so closely that from the point of view of external
+form they seem to be nearly in contact.</p>
+
+<p>The tendon, after receiving the small fasciculus from the
+common extensor (<a href="#Fig075">Fig. 75</a>, 16), as well as a fibrous band
+emanating from the external surface of the carpus (<a href="#Fig075">Fig. 75</a>,
+17), is situated at the external side of the tendon of the
+anterior extensor of the phalanges, and is inserted into the
+anterior surface of the superior extremity of the first
+phalanx.</p>
+
+<p>This muscle extends the digit or digits into which it is
+inserted. It also assists in the movement of extension of
+the hand as a whole.</p>
+
+<p><b>Posterior Ulnar</b> (<i>Extensor carpi ulnaris</i>) (<a href="#Fig073">Fig. 73</a>, 11;
+<a href="#Fig074">Fig. 74</a>, 17; <a href="#Fig075">Fig. 75</a>, 18).&mdash;Designated by veterinary
+anatomists as the <i>external flexor of the metacarpus</i>,<a name="FNanchor_27_27" id="FNanchor_27_27"></a><a
+href="#Footnote_27_27" class="fnanchor">[27]</a> or
+<i>external cubital</i>, this muscle is situated in the posterior region
+of the external surface of the forearm, behind the lateral
+extensor of the phalanges.</p>
+
+<div class="footnote"><p><a name="Footnote_27_27" id="Footnote_27_27"></a><a href="#FNanchor_27_27"><span class="label">[27]</span></a>
+Certain authors give it the name of <i>ulnar extensor of the wrist</i>. It is true
+that in the human being this is its action; but in quadrupeds, owing to its
+insertion into the pisiform, it draws the hand into the position of flexion.</p></div>
+
+<p>It arises from the epicondyle; its fleshy body, thick but
+flattened, is directed vertically towards the carpus, and its
+tendon is inserted into the external part of the superior
+extremity of the metacarpus, after having given off a
+fibrous band, which takes its attachment on the pisiform.</p>
+
+<p>It is inserted, in the cat and the dog, into the superior
+extremity of the fifth metacarpal; in the pig to the external
+metacarpal; in the ox to the external side of the canon-bone;
+in the horse to the superior extremity of the external
+rudimentary metacarpal.</p>
+
+<p>This muscle flexes the hand on the forearm, and in animals
+in which the radio-carpal articulation permits, by its
+formation, it inclines the hand slightly outwards&mdash;that is,
+abducts it.</p>
+
+<p><a name="Anconeus" id="Anconeus"></a><b>Anconeus</b> (<a href="#Fig072">Fig. 72</a>,
+17; <a href="#Fig073">Fig. 73</a>, 13).&mdash;We have already
+stated (<a href="#Page_174">p. 174</a>) that the anconeus is included with the triceps<span
+class="pagenum"><a name="Page_186" id="Page_186">[186]</a></span>
+brachialis in zoological anatomy, and that veterinary
+anatomists give it the name of <i>small extensor of the forearm</i>.<a name="FNanchor_28_28"
+id="FNanchor_28_28"></a><a href="#Footnote_28_28" class="fnanchor">[28]</a></p>
+
+<div class="footnote"><p><a name="Footnote_28_28" id="Footnote_28_28"></a><a href="#FNanchor_28_28"><span class="label">[28]</span></a>
+It is also called by some authors, the <i>small anconeus</i>.</p></div>
+
+<p>In the dog it recalls, as to position, the human anconeus,
+but with this difference&mdash;that, in the latter, the anconeus,
+triangular in outline, has one of its angles turned outwards
+(the epicondyloid attachment) and one of its sides turned
+towards the olecranon. Here it is entirely the opposite.
+The anconeus, similarly triangular, is broader externally.
+At this level it takes its origin from the external border of
+the humerus, the epicondyle, and the external lateral ligament
+of the articulation of the elbow; thence its fibres
+converge towards the external surface of the olecranon, to
+be there inserted.</p>
+
+<p>It is in relation, anteriorly and inferiorly, with the posterior
+ulnar muscle. It is covered superiorly by the external head
+of the triceps. In the cat the disposition of the anconeus
+is analogous. But in the other quadrupeds with which we
+are here concerned it is completely covered by the external
+head of the triceps. It really participates in the
+formation of the triceps; and seeing that it takes origin from
+the posterior surface of the humerus at the margin of the
+olecranon fossa (<a href="#Fig072">Fig. 72</a>), and proceeds thence towards the
+olecranon to be inserted, we can understand why veterinary
+anatomists have connected its study with that of the
+posterior muscular mass of the arm.</p>
+
+<p>This muscle is an extensor of the forearm on the arm.</p>
+
+<p>We proceed now to inquire what the deep muscles of the
+posterior region of the human forearm become in quadrupeds:
+the long abductor of the thumb, the short extensor
+of the thumb, the long extensor of the thumb, the proper
+extensor of the index. We know that in every instance
+these muscles, which are deeply seated at their origin,
+become superficial afterwards.</p>
+
+<p>In quadrupeds, on account of the position in which the
+forearm is placed&mdash;viz., pronation&mdash;the corresponding
+muscles occupy the anterior aspect of this region.</p>
+
+<p><b>Long Abductor of the Thumb</b> (<i>Extensor ossis metacarpi</i><span
+class="pagenum"><a name="Page_187" id="Page_187">[187]</a></span>
+<i>pollicis</i>) <b>and Short Extensor of the Thumb</b> (<i>Extensor primi
+internodii pollicis</i>) (<a href="#Fig073">Fig. 73</a>, 14; <a href="#Fig074">Fig. 74</a>,
+19; <a href="#Fig075">Fig. 75</a>, 20).&mdash;United
+one to the other in man, blended in quadrupeds,
+they form in the latter the muscles to which veterinary
+anatomists give the name of <i>oblique extensor of the metacarpus</i>.</p>
+
+<p>This muscle arises from the median portion of the skeleton
+of the forearm. There it is covered by the common extensor
+of the digits and that of the small digit (anterior extensor
+and lateral extensor of the phalanges). Then, at the internal
+border of the first of these muscles, it becomes superficial,
+passes downwards and inwards, crosses superficially
+the anterior extensor of the metacarpus, reaches the inferior
+extremity of the radius, and becomes lodged in the most
+internal of the grooves situated on the anterior surface
+of this extremity, passes on the internal side of the carpus,
+and is inserted into the superior extremity of the most
+internal metacarpal&mdash;that is, to the first metacarpal, or metacarpal
+of the thumb&mdash;in the dog and cat; to the internal
+rudimentary metacarpal in the horse.</p>
+
+<p>It is an extensor of the metacarpal into which it is inserted;
+but as, if we recall the extreme examples given
+above, in the dog the first metacarpal is not very mobile,
+and in the horse the internal rudimentary metacarpal is
+absolutely fixed to the bone which it accompanies, it is
+more exact to add that this muscle is principally an extensor
+of the metacarpus as a whole.</p>
+
+<p>And yet, in the cat and the dog, it is also able to adduct
+the first metacarpal bone. It must be understood that this
+movement would be abduction, if the hand could be placed
+in the position of complete supination, as in the human
+species.</p>
+
+<p><b>Long Extensor of the Thumb</b> (<i>Extensor secundi internodii
+pollicis</i>) <b>and Proper Extensor of the Index</b> (<i>Extensor indicis</i>).&mdash;These
+two muscles are blended together by their fleshy
+bodies, so that the single name of <i>proper extensor of the thumb
+and index</i> is preferable. This muscle is but of slight importance
+from our point of view, for it is extremely atrophied,
+and so much the more as the number of the digits is lessened.</p>
+
+<p><span class="pagenum"><a name="Page_188" id="Page_188">[188]</a></span>It arises, as the preceding, from the skeleton of the forearm,
+and there it is deeply placed. Below, towards the
+carpus, its tendinous part becomes superficial, to end in the
+following manner:</p>
+
+<p>In the carnivora, the tendon divides into two very slender
+parts, which are inserted into the thumb and the index.
+In the pig, the tendon is blended with that of the common
+extensor of the internal digits. Finally, in the ox and the
+horse, it is sometimes regarded as being blended with the
+common or anterior extensor of the phalanges. But to us it
+appears more rational to say that it does not exist, which,
+moreover, is explained by the digital simplification of the
+hand.</p>
+
+<h5>Internal and Posterior Region</h5>
+
+<p><b>Pronator Teres</b> (<a href="#Fig076">Fig. 76</a>, 8).&mdash;This muscle, as may easily
+be understood, undergoes, as do the supinators, a degree
+of degeneration in proportion to the loss of mobility of the
+radius on the ulna. In animals in which the bones of the
+forearm are not fused it exists; in those, on the other
+hand, in which this segment has become simply a supporting
+column, it is not developed&mdash;at least, in a normal
+manner.</p>
+
+<p>It is, consequently, found best marked in the dog and
+the cat.</p>
+
+<p>Forming, as in man, the internal limit of the hollow of the
+elbow, the pronator teres has a disposition analogous to that
+which characterizes the corresponding muscle in the human
+species. It arises from the epitrochlea (internal condyle),
+proceeds downwards and outwards, and is inserted into the
+middle portion of the body of the radius.</p>
+
+<p>It is into the hollow in front of the elbow, which this
+muscle contributes to limit, that the biceps and the brachialis
+anticus dip.</p>
+
+<p>In the pig and the ox it is atrophied.</p>
+
+<p>In the horse it does not exist. We may, however,
+sometimes find it, but in an abnormal form. We were
+able to demonstrate its presence in the form of a fleshy<span class="pagenum"><a name="Page_189" id="Page_189">[189]</a></span>
+tongue situated on the internal side of the elbow (<a href="#Fig078">Fig. 78</a>)
+in a horse which we dissected many years ago in the laboratory
+of the School of Fine Arts. Moreover&mdash;and the fact
+seemed to us an interesting one&mdash;the forearm to which the
+muscle belonged had an ulna of relatively considerable
+development (<a href="#Fig079">Figs. 79</a> and <a href="#Fig080">80</a>).<a name="FNanchor_29_29"
+id="FNanchor_29_29"></a><a href="#Footnote_29_29" class="fnanchor">[29]</a></p>
+
+<div class="footnote"><p><a name="Footnote_29_29" id="Footnote_29_29"></a><a href="#FNanchor_29_29"><span class="label">[29]</span></a>
+&Eacute;douard Cuyer, &#8216;Abnormal Length of the Ulna and Presence of a
+Pronator Teres Muscle in a Horse&#8217; (<i>Bulletin de la Soci&eacute;t&eacute; d&#8217;Anthropologie</i>,
+Paris, 1887).</p></div>
+
+<p>This muscle is a pronator.</p>
+
+<p><b>Flexor Carpi Radialis</b> (<a href="#Fig076">Fig. 76</a>, 10; <a href="#Fig077">Fig. 77</a>, 7).&mdash;Called
+by veterinary anatomists <i>the internal flexor of the
+metacarpus</i>, this muscle, which is found on the internal
+aspect of the forearm, is situated behind the pronator
+teres when this muscle exists, whilst in the animals which
+are deprived of the latter the flexor carpi radialis has in
+front of it the internal border of the radius, which separates
+it from the anterior extensor of the metacarpus.</p>
+
+<p>It is necessary to add that the flexor carpi radialis is
+similarly separated from the anterior extensor of the metacarpus
+by the internal border of the radius in animals
+in which the pronator teres exists, but then only in that part
+of the forearm which is situated below this latter.</p>
+
+<p>The flexor carpi radialis arises from the epitrochlea. Its
+fleshy body, fusiform in shape, descends vertically, and
+terminates in a tendon on the posterior surface of the
+bases of the second and third metacarpals in the dog and
+the cat, on the metacarpal of the large internal digit in
+the pig, on the internal side of the metacarpus in the ox,
+and on the superior extremity of the internal rudimentary
+metacarpal in the horse.</p>
+
+<p>We see clearly, in this latter, a superficial vein which, in
+the shape of a strong cord, passes along the anterior border
+of the flexor carpi radialis; it is the subcutaneous median
+or internal vein, which, forming the continuation of the
+internal metacarpal vein, joins the venous system of the
+arm, after having crossed obliquely the corresponding part
+of the radius.</p>
+
+<p><b>Palmaris Longus.</b>&mdash;This muscle, which exists distinctly in<span class="pagenum"><a
+name="Page_190" id="Page_190">[190]</a></span>
+some animals, but whose absence is far from being rare in
+the human species, is not developed as a distinct muscle in
+any of the domestic quadrupeds.</p>
+
+<div class="figmed"><a name="Fig076" id="Fig076"></a>
+<img src="images/illo213.png" alt="Fig. 76" width="300" height="514" />
+<p class="caption just">Fig. 76.&mdash;Myology of the Dog: Left Anterior Limb, Internal Aspect.</p>
+
+<p class="subcaption just">1, Biceps; 2, long extensor of the forearm (supplementary or accessory
+muscle of the great dorsal); 3, triceps, long head; 4, triceps, internal
+head; 5, olecranon; 6, epitrochlea (internal condyle); 7, radial extensors
+(anterior extensor of the metacarpus); 8, pronator teres; 9, radius; 10,
+flexor carpi radialis (internal flexor of the metacarpus); 11, anterior ulnar
+(oblique flexor of the metacarpus); 12, superficial flexor of the digits;
+13, deep flexor of the digits; 14, flexor longus pollicis (radial fasciculus
+of the deep flexor of the digits); 15, pisiform bone.</p></div>
+
+<p><span class="pagenum"><a name="Page_191" id="Page_191">[191]</a></span>And yet some authors announce its presence in the
+dog, and describe it as becoming detached, in the form
+of a cylindrical bundle, from the anterior surface of the
+fleshy mass of the deep flexor of the digits (see <a href="#Page_196">p. 196</a>)
+to proceed then by a tendon which divides into two parts,
+to terminate in the palm of the hand, where it blends
+with the tendons of the superficial flexor, which are destined
+for the third and fourth digits.</p>
+
+<p>These authors give to this muscle the name of <i>palmaris
+longus</i>, and attribute to it the action of flexing the hand.</p>
+
+<p><b>Anterior Ulnar</b> (<i>Flexor carpi ulnaris</i>) (<a href="#Fig073">Fig. 73</a>, 16; <a href="#Fig076">Fig.
+76</a>, 11; <a href="#Fig077">Fig. 77</a>, 8).&mdash;Called by veterinary anatomists the
+<i>oblique flexor of the metacarpus</i>, or <i>internal ulnar</i>, this
+muscle occupies the internal part of the posterior aspect of
+the forearm in the ox and the horse, while in the dog it
+occupies rather the external part.</p>
+
+<p>This difference arises from the fact that in this latter, as
+in man, the anterior ulnar is separated from the flexor carpi
+radialis by an interval in which we see, on the internal aspect
+of the forearm, just at the level of the elbow, the flexors of
+the digits. This interval is so much the wider as there is
+no palmaris muscle to subdivide its extent (<a href="#Fig081">Fig. 81</a>). In
+the horse, the interval in question does not exist. In this
+animal, indeed, the anterior ulnar is in contact with the
+radial flexor, so that this muscle can occupy only a region
+belonging rather to the internal surface of the forearm
+(<a href="#Fig082">Fig. 82</a>).</p>
+
+<p>In the dog the anterior ulnar is in contact with the posterior
+ulnar. This relation recalls that which is found in man,
+where the two muscles are merely separated by the crest of
+the ulna (<a href="#Fig081">Fig. 81</a>). But in the horse, in which the anterior
+ulnar has, so to speak, slid towards the internal aspect,
+this muscle is separated above from the posterior ulnar,
+and it is in the interval separating these two muscles that
+we are able to perceive, but this time at the back of the
+forearm, the muscular mass of the flexors of the digits
+(<a href="#Fig082">Fig. 82</a>).</p>
+
+<p class="pagenum"><a name="Page_192" id="Page_192">[192]</a></p>
+
+<div class="figmed"><a name="Fig077"  id="Fig077"></a>
+<img src="images/illo215.png" alt="Fig. 77" width="275" height="567" />
+<p class="caption just">Fig. 77.&mdash;Myology of the Horse: Anterior Limb, Left Side,
+Internal Aspect.</p>
+
+<p class="subcaption just">1, Long extensor of the forearm (supplementary or accessory muscle of
+the latissimus dorsi); 2, radialis muscles (anterior extensor of the metacarpus);
+3, tendons of extensor ossis metacarpi pollicis extensor
+primi internodii pollicis united (oblique extensor of the metacarpus);
+4, tendon of extensor communis digitorum (anterior extensor of the
+phalanges); 5, strengthening band from the suspensory ligament of the
+fetlock; 6, internal surface of the radius; 7, flexor carpi radialis (internal
+flexor of the metacarpus); 8, anterior ulnar (oblique flexor of the metacarpus);
+9, pisiform bone; 10, 10, tendon of the superficial flexor of the
+digits (superficial flexor of the phalanges); 11, 11, tendon of the deep
+flexor of the digits (deep flexor of the phalanges); 12, sesamoid prominence;
+13, suspensory ligament of the fetlock; 14, internal rudimentary metacarpal.</p></div>
+
+<p>The anterior ulnar arises above from the epitrochlea and
+the olecranon; thence it is directed towards the carpus,<span class="pagenum"><a name="Page_193" id="Page_193">[193]</a></span>
+to be inserted into the pisiform bone. It proceeds therefore
+from the inner side of the elbow to the outer side
+of the upper part of the hand; it consequently crosses the
+posterior surface of the forearm obliquely. This is why, as
+we have pointed out above, it receives the name of the
+oblique flexor of the metacarpus.</p>
+
+<p>It is not unprofitable to recall in this connection that
+there is an internal flexor of the metacarpus, which is the
+flexor carpi radialis; and an external flexor of the metacarpus,
+which is the posterior ulnar (in human anatomy,
+extensor carpi ulnaris). It is between these two muscles
+that we find the oblique flexor&mdash;the anterior ulnar which we
+have just been studying.</p>
+
+<p>This muscle flexes the hand on the forearm.</p>
+
+<p><b>Superficial Flexor of the Digits</b> (<i>Flexor digitorum sublimis</i>)
+(<a href="#Fig076">Fig. 76</a>, 12; <a href="#Fig077">Fig. 77</a>, 10, 10).&mdash;This muscle arises from
+the epitrochlea; thence it passes towards the hand, becomes
+tendinous, passes in a groove on the posterior aspect of the
+carpus, and terminates on the palmar surface of the phalanges
+in furnishing a number of tendons proportioned to the digital
+division of the hand. Whatever the number, to which we
+will again refer, each tendon is attached to the second phalanx,
+after bifurcating at the level of the first, so as to form a sort
+of ring, destined to give passage to the corresponding tendon
+of the deep flexor. This ring and this passage have gained
+for the muscle the name of <i>perforated flexor</i>.</p>
+
+<p>In the dog and the cat the principal tendon is divided
+into four parts, which go to the four last digits.</p>
+
+<p>In the ox it is divided into two parts only; as, moreover,
+in the pig, whose superficial flexor is destined for
+the two large digits only, the lateral digits receiving no
+part of it.</p>
+
+<p>Finally, in the horse the tendon is single.</p>
+
+<p>We have previously pointed out that in the carnivora
+this muscle is visible on the internal and posterior aspects
+of the forearm, in the interval which is limited in front by
+the flexor carpi radialis and behind and outside by the
+anterior ulnar.</p>
+
+<p>Certain details are still to be added to the description of<span class="pagenum"><a name="Page_194" id="Page_194">[194]</a></span>
+this muscle. We will enter on an analysis of them after we
+have given some indications relative to the following muscle:</p>
+
+<p><b>Deep Flexor of the Digits</b> (<i>Flexor digitorum profundus</i>)
+(<a href="#Fig075">Fig. 75</a>, 21, 22; <a href="#Fig076">Fig. 76</a>, 12; <a href="#Fig077">Fig. 77</a>, 11, 11).&mdash;This muscle
+is covered by the superficial flexor. It arises from the
+epitrochlea, from the radius, and from the ulna, either from
+the olecranon process&mdash;as in the ox, pig, and horse&mdash;or from
+almost the whole extent of the shaft of the same bone, as in
+the cat and dog.</p>
+
+<div class="figmed"><a name="Fig078" id="Fig078"></a>
+<img src="images/illo217.png" alt="Fig. 78" width="300" height="441" />
+<p class="caption just">Fig. 78.&mdash;Left Anterior Limb of the Horse: Internal Aspect.</p>
+
+<p class="subcaption just">1, Internal flexor of the metacarpus or great palmar; 2, inferior part
+of the biceps; 3, inferior part of the brachialis anticus; 4, internal lateral
+ligament of the elbow; 5, pronato teres muscle.</p></div>
+
+<p>The radial fasciculus represents in the domestic quadrupeds
+the long proper flexor muscle of the thumb in man.
+For this reason we shall describe the muscle afresh in the
+following paragraph:</p>
+
+<p>The fleshy bundles of which we have just spoken terminate
+in a tendon which afterwards divides into slips, the<span class="pagenum"><a name="Page_195" id="Page_195">[195]</a></span>
+number of which is in proportion to the digital division of
+the hand. These slips then pass through the slit or <i>buttonhole</i>
+in the tendon of the superficial flexor, and proceed
+to terminate on the third phalanx; hence the name of
+<i>perforating</i>, which is also given to the deep flexor of the
+digits.</p>
+
+<p>In the dog and the cat the tendon is divided into five
+portions, each of which proceeds to one of the digits. The
+internal tendon, which is destined for the thumb, terminates
+on the second phalanx of this digit.</p>
+
+<p>In the pig the tendon divides into four tendons destined
+for the four digits.</p>
+
+<p>In the ox there are but two tendons.</p>
+
+<p>In the horse the tendon is single.</p>
+
+<p>As their names indicate, these muscles, both superficial
+and deep, flex the digits. In addition to this, they flex
+the hand on the forearm.</p>
+
+<p>We mentioned above that certain details relative to
+the superficial flexor must be analyzed in a special way.
+We now add that this should also be done with regard to
+the deep flexor. The point in question is the arrangement
+which the tendons of these muscles present at the level of
+the palmar region of the hand.</p>
+
+<p>It is easy, in the case of the dog or the cat, to picture to
+one&#8217;s self this arrangement, especially if we recollect that
+which exists in the human species. The tendons of the
+flexors are placed on a kind of muscular bed formed by the
+union of the muscles of the region, but, moreover, from the
+point of view of external form, these tendons are not of very
+great importance.</p>
+
+<p>But in the ox and the horse it is quite otherwise. From
+the simplification of the skeleton of the hand, and the
+reduction of the number of movements which the bones
+that form it are able to execute, there naturally results a
+diminution of its muscular apparatus. Apart from the
+existence of muscular vestiges of but little importance, we
+can say that, in reality, the hand does not possess any
+muscles. On its palmar aspect are found only the tendons
+of the flexors of the digits, and as these tendons are<span class="pagenum"><a name="Page_196" id="Page_196">[196]</a></span>
+large, and the hand long, they give origin to external
+forms which it is necessary to examine.</p>
+
+<div class="figmed"><a name="Fig079" id="Fig079"></a>
+<img src="images/illo219a.png" alt="Fig. 79" width="125" height="487" />
+<p class="caption just">Fig. 79.&mdash;Left Anterior Limb
+of the Horse: External
+Aspect.</p>
+
+<p class="subcaption just">1, Ulna of abnormal length.</p></div>
+
+<div class="figmed"><a name="Fig080" id="Fig080"></a>
+<img src="images/illo219b.png" alt="Fig. 80" width="125" height="389" />
+<p class="caption just">Fig. 80.&mdash;Left Anterior Limb
+of the Horse: External
+Aspect.</p>
+
+<p class="subcaption just">1, Normal ulna.</p></div>
+
+<p>In the horse, which we take as a type, the tendons
+of the flexors, after being retained in position at the carpus
+by a fibrous band, the <i>carpal sheath</i>, which recalls the anterior
+annular ligament of the human carpus, and having passed
+this region, descend vertically, remaining separated from
+the posterior surface of the metacarpus, so that the skin
+sinks slightly on the lateral parts in front of the thick cord
+which these tendons form. This cord is known by the name
+of <i>tendon</i>.</p>
+
+<p>The flexors then reach the fetlock, and occupy the groove<span class="pagenum"><a name="Page_197" id="Page_197">[197]</a></span>
+formed by the peculiar arrangement of the two large sesamoid
+bones. They are retained in position at this level by
+a fibrous structure, which forms the metacarpo-phalangeal
+sheath. They then reach the phalanges, being directed
+obliquely downwards and forwards, as, moreover, the latter
+are also inclined. Then the tendon of the superficial flexor
+divides into two slips, which are inserted into the second
+phalanx, between which slips passes the tendon of the deep
+flexor, which in its turn goes to be inserted, in the form of an
+expansion, into the semilunar crest, by which the inferior
+surface of the third phalanx is divided into two parts.<a name="FNanchor_30_30"
+id="FNanchor_30_30"></a><a href="#Footnote_30_30" class="fnanchor">[30]</a></p>
+
+<div class="footnote"><p><a name="Footnote_30_30" id="Footnote_30_30"></a><a href="#FNanchor_30_30"><span class="label">[30]</span></a>
+See, as regards this crest, in the paragraph relative to the hoof of the
+solipeds, the figures which represent the third phalanx, viewed on its
+inferior surface (<a href="#Fig101">Figs. 101</a> and <a href="#Fig102">102</a>, p. 258).</p></div>
+
+<p>The part which these tendons play is of great importance
+in the large quadrupeds.</p>
+
+<p>These tendons, in fact, in addition to the action determined
+by the contraction of the fleshy fibres to which
+they succeed, maintain the angle formed by the canon-bone
+and the phalangeal portion of the hand, and prevent
+its effacement under the weight of the body during
+the time of standing. Their strong development, and the
+position they occupy, make this understood, without it
+being necessary to insist on it further.</p>
+
+<p>We mentioned above that the &#8216;tendon&#8217; descends vertically
+from the carpus towards the fetlocks. This is as it
+should be. But, in some horses, it is oblique downwards
+and backwards, so that the canon, instead of being of equal
+depth from before backwards in its whole length, is a little
+narrower in its upper part.</p>
+
+<p>This results from the fact that the tendons of the flexors,
+too firmly bound by the carpal sheath, gradually separate
+as they pass from the metacarpus, going to join the fetlock;
+hence the obliquity pointed out above. This abnormality
+producing a deleterious result, in the sense that the
+tendinous apparatus acts with less strength as an organ of
+support, it constitutes a defect of conformation which is
+expressed by saying that the tendon has &#8216;failed.&#8217;</p>
+
+<p><b>Long Proper Flexor of the Thumb</b> (<i>Flexor longus</i><span class="pagenum"><a name="Page_198" id="Page_198">[198]</a></span>
+<i>pollicis</i>) (<a href="#Fig076">Fig. 76</a>, 14).&mdash;As we have already pointed out,
+this muscle is represented in quadrupeds by the radial
+bundle of the deep flexor of the digits, so that the two
+muscles are in reality blended the one to the other. This
+union is sometimes found, but only as an abnormality, in
+the human species. We have met some examples of this
+in the course of our dissections.</p>
+
+<p><b>Pronator Quadratus.</b>&mdash;This muscle conforms to the general
+law which we have already pointed out in connection with
+those which have for their action the rotation of the radius
+around the ulna. We remember, indeed, that when the
+bones of the forearm are fused with one another, the muscles
+which are destined to produce a mobility which has then
+become impossible disappear at the same blow.</p>
+
+<div class="figmed"><a name="Fig081" id="Fig081"></a>
+<img src="images/illo221a.png" alt="Fig. 81" width="250" height="197" />
+<p class="caption just">Fig. 81.&mdash;Diagram of the Posterior
+Part of a Transverse
+Section passing
+through the Middle of
+the Left Fore-limb of the
+Dog: Surface of the
+Inferior Segment of the
+Section.</p>
+
+<p class="subcaption just">1, Radius; 2, ulna; 3, posterior
+ulnar; 4, anterior ulnar;
+5, great palmar (<i>flexor carpi
+radialis</i>); 6, flexors of the digits.</p></div>
+
+<div class="figmed"><a name="Fig082" id="Fig082"></a>
+<img src="images/illo221b.png" alt="Fig. 82" width="250" height="219" />
+<p class="caption just">Fig. 82.&mdash;Diagram of a Horizontal
+Section of the
+Middle of the Forearm of
+the Left Leg of the Horse:
+Surface of the Inferior
+Segment of the Section.</p>
+
+<p class="subcaption just">1, Radius; 2, ulna; 3, posterior
+ulnar; 4, anterior ulnar; 5, great
+palmar (<i>flexor carpi radialis</i>); 6,
+flexors of the digits.</p></div>
+
+<p>For this cause we do not find the square pronator in
+either the ox or the horse, but can demonstrate its presence
+in the dog and the cat.</p>
+
+<p>It is very deeply situated. This is why, and also on
+account of the plan which we have traced for ourselves, we
+will simply say that it is situated on the postero-internal<span class="pagenum"><a name="Page_199" id="Page_199">[199]</a></span>
+aspect of the skeleton of the forearm, and that it extends
+from the ulna to the radius.</p>
+
+<p>It seems to us, however, sufficiently interesting to add
+that, instead of occupying, as in the human species, the
+inferior fourth of the two bones, it extends, particularly in
+the dog, over their whole length, with the exception of their
+superior and inferior extremities.</p>
+
+<h5>Muscles of the Hand</h5>
+
+<p>We will first recall that, in man, the palm of the hand
+is divided into three regions: a median palmar region,
+which is occupied by the tendons of the flexors of the
+digits, the lumbricales, and, deeply, by the interosseous
+muscles; an external region, or thenar eminence, formed
+by the muscles destined for the movements of the thumb;
+an internal region, or hypothenar eminence, which contains
+the muscles proper to the small digit and the palmar
+cutaneous muscle.</p>
+
+<p>These muscles are found, more or less developed, in the
+dog and the cat.</p>
+
+<p>In the ox and the horse we meet with no vestige of the
+muscles of the thenar or hypothenar eminences. Nevertheless,
+in these animals we find the muscles which belong
+to the central region of the palm. We refer to the
+lumbricales and the interosseous.</p>
+
+<p>Although this fact has no relation to the object of our
+study, it appears to us interesting to announce that there
+are traces of the lumbricales found in the solipeds.
+These muscles are represented by two fleshy bundles,
+situated one on each side of the tendon of the deep flexor,
+above the ring of the tendon of the superficial flexor.
+These small muscles are continued as slender tendons,
+which become lost in the fibrous tissue of the <i>spur</i>, which
+is the horny process situated at the posterior part of the
+fetlock, and which is covered by the hairs, more or less
+abundant, which constitute the <i>wisp</i>.</p>
+
+<p>As for the interosseous muscles, they are represented by
+the <i>suspensory ligament of the fetlock</i>, and by two other<span class="pagenum"><a name="Page_200" id="Page_200">[200]</a></span>
+small muscles, tendinous throughout, which are situated
+between the principal metacarpal and the rudimentary ones.</p>
+
+<p>The suspensory ligament of the fetlock is considered an
+interosseous muscle, on account of the red fleshy striations
+which it contains, and from certain relations which it forms
+with the tendon of the common extensor of the digits or
+anterior extensor of the phalanges. This ligament (<a href="#Fig075">Fig. 75</a>,
+26; <a href="#Fig077">Fig. 77</a>, 13), which plays an important part in the
+standing position as a support of the foot, is a fibrous
+band situated between the tendons of the flexors of the
+digits and the principal metacarpal. It arises above, from
+the second row of the carpals, descends towards the fetlock,
+where it divides into two branches, which are inserted into
+the large sesamoid bones. At the same level, this ligament
+gives off two fibrous bands which, passing downwards and
+forwards, join the tendon of the anterior extensor of the
+phalanges, blending with it, after having each crossed one
+of the lateral aspects of the pastern. We have already
+referred to these bands (<a href="#Page_183">p. 183</a>).</p>
+
+<p>It is with these latter that are blended the long and
+slender tendons which form in a great measure the two
+other interosseous muscles previously described.</p>
+
+<p>A ligament of the same kind is found in the ox
+(<a href="#Fig074">Fig. 74</a>, 23).</p>
+
+<h4>MUSCLES OF THE POSTERIOR LIMBS</h4>
+
+<h5>Muscles of the Pelvis</h5>
+
+<p>The muscles which specially interest us in this region,
+because of their superficial position, are the gluteus maximus
+and the gluteus medius. As for the gluteus minimus, it is
+deeply situated, and more or less sharply marked off from
+the second of the preceding muscles.</p>
+
+<p>Inasmuch as the gluteus medius is more simple in arrangement
+than the maximus, and will aid us in arranging our
+ideas in connection with the latter, it is with the study of it
+that we will commence.</p>
+
+<p><b>Gluteus Medius</b> (<a href="#Fig068">Fig. 68</a>, 29; <a href="#Fig069">Fig. 69</a>, 26;
+<a href="#Fig070">Fig. 70</a>, 35).&mdash;This<span class="pagenum"><a name="Page_201" id="Page_201">[201]</a></span>
+muscle, as in man, occupies the external iliac fossa.
+But this latter being directed differently in the digitigrades
+and the ungulates, as we have pointed out in the section
+on osteology (see <a href="#Page_91">pp. 91</a> and <a href="#Page_99">99</a>), the muscle in question
+has consequently not the same direction in the two groups
+of animals, being turned outwards in the first, and upwards
+in the second.</p>
+
+<p>It is the thickest of the glutei, and gives to the region
+which it occupies a rounded form.</p>
+
+<p>From the iliac fossa from which it arises the fleshy fibres
+are directed towards the femur, to be inserted into the
+great trochanter. It is covered by an aponeurosis, and
+in part by the great gluteal. It completely covers the
+small gluteal, which veterinary anatomists designate by
+the name of the <i>deep gluteal</i>.</p>
+
+<p>In the carnivora it does not pass in front of the iliac
+crest, but, in the ox, and more particularly in the horse, it is
+prolonged anteriorly, and thus covers, to a certain extent,
+the muscles of the common mass.</p>
+
+<p>When it contracts, taking its fixed point at the pelvis,
+the gluteus medius extends the thigh, which it is also able
+to abduct. If, on the other hand, its fixed point is on
+the femur, it acts on the trunk, which it raises, producing
+oscillating movements of the pelvis. It contributes in
+this way to the action of rearing. We also see it distinctly
+appear by the prominence which it produces in
+the dog, which, according to the time-honoured phrase,
+<i>fait le beau</i>.</p>
+
+<p><b>Gluteus Maximus</b> (<a href="#Fig068">Fig. 68</a>, 28; <a href="#Fig069">Fig. 69</a>, 25; <a href="#Fig070">Fig. 70</a>,
+33, 34).&mdash;The great gluteal muscle, further designated in
+veterinary anatomy the <i>superficial gluteal</i>, is proportionately
+less developed in quadrupeds than in man. Indeed, in the
+latter, where it is of very great thickness, its volume is
+due to the important function which it fulfils in maintaining
+the biped attitude.</p>
+
+<p>In quadrupeds it contributes to form the superficial part
+of the crupper and the external surface of the thigh. It is
+divided into two parts: one anterior, the other posterior.</p>
+
+<p>With regard to this latter, it will be necessary to indicate<span class="pagenum"><a name="Page_202" id="Page_202">[202]</a></span>
+how it has been sometimes regarded, and to what portion
+of the muscular system in man it corresponds. But we
+believe that it is better to see beforehand, without any preconceived
+idea, how these two parts are arranged.</p>
+
+<p>In the dog, the anterior portion of the gluteus maximus
+arises from the sacrum, while some fibres situated further
+forward arise from the surface of the gluteus medius, near the
+iliac spine, and from the tensor of the fascia lata with which
+these fibres are blended. The posterior portion, united to
+the preceding&mdash;that is to say, to those of its fibres which
+arise from the sacrum&mdash;takes its origin from the first
+coccygeal vertebra. These two portions are directed
+towards the femur, to be inserted into the great trochanter,
+and to the external branch of the superior bifurcation of
+the linea aspera.</p>
+
+<p>In the cat, the posterior bundle is less definitely blended
+with the anterior. By a long and slender tendon which,
+behind, turns around the great trochanter, and passes along
+the surface of the fascia lata, it proceeds to join the knee-cap.</p>
+
+<p>In the pig, the posterior portion is much more developed.</p>
+
+<p>In the horse, the anterior portion arises from the internal
+iliac spine (posterior in man), from the external iliac spine
+(anterior in man), and, between these two osseous points,
+from the aponeurosis, which covers the gluteus medius.
+Between these two origins the muscle is deeply grooved,
+so that the tendency is to divide into two portions, each of
+which is directed towards one of the iliac angles. In this
+groove the gluteus medius is to be seen.</p>
+
+<p>The fleshy bundles converge, and are directed towards the
+external aspect of the femur, to be inserted into the osseous
+prominence known as the third trochanter, after passing
+beneath the fleshy fibres of the posterior portion. The
+latter, which is more considerable than the preceding portion,
+arises above from the sacral crest, from the aponeurosis
+which envelops the coccygeal muscles, from the sacro-sciatic
+ligament, and from the tuberosity of the ischium.
+From this origin it passes downwards, expands, then,
+describing a curve with the convexity behind, it becomes<span class="pagenum"><a name="Page_203" id="Page_203">[203]</a></span>
+narrowed, and proceeds to be inserted by a deep fasciculus
+into the third trochanter, to the fascia lata, and, lastly,
+to the knee-cap by the inferior part of its tendon.</p>
+
+<p>Above, its posterior border is covered by the semi-tendinosus;
+interiorly, the same border is in relation with the
+biceps femoris.</p>
+
+<p>In the ox, the two parts of the great gluteal muscle are
+blended together.</p>
+
+<p>The long and broad fleshy band which they form
+arises in a manner corresponding to that which we have
+just indicated in connection with the horse, except that it
+has no attachment to the femur. The fascia lata adheres
+strongly to its anterior border for a considerable length.
+The form of the superior border of the great gluteal muscle
+of this animal differs from that of the analogous portion
+in the horse. This difference results from the peculiar
+aspect which the corresponding region of the pelvis presents,
+and from the fact that, in the ox, as the semi-tendinosus
+does not cover the portion of the great gluteal which
+arises from the tuberosity of the ischium, the attachments
+of this muscle to the sacro-sciatic ligament are
+uncovered.</p>
+
+<p>Its descending portion, as a whole, has a rectilinear form,
+and does not form a curve such as we indicated in the case
+of the horse.</p>
+
+<p>The anterior portion of the great gluteal flexes the thigh.
+As regards the posterior portion, it extends the thigh, and
+abducts it.</p>
+
+<p>The action of this latter portion is particularly interesting
+as regards the horse, because of the great development of
+the muscular mass which this region presents in this animal.
+If the muscle takes its fixed point above, it acts, in the
+extension of the thigh during walking, by projecting the
+trunk forward during the whole time that the hind-limb to
+which it belongs is in contact with the ground. If, on the
+contrary, it takes its fixed point below, it makes the pelvis
+describe a see-saw movement, upwards and backwards, on
+the coxo-femoral articulation, and so contributes to the
+action of rearing.</p>
+
+<p><span class="pagenum"><a name="Page_204" id="Page_204">[204]</a></span>Now that we have a knowledge of the disposition of the
+great gluteal muscle, the moment has come to inquire what is
+the signification of its posterior portion. The action of the
+anterior part being clearly comparable to the human great
+gluteal, there can be no doubt as regards the homology of
+this portion, so we will not insist on it further.</p>
+
+<p>Of the posterior portion it is wholly different, for it is the
+homologue of a fleshy bundle annexed to the great gluteal of
+man, but which is not developed except as an abnormality.</p>
+
+<p>Indeed, we sometimes find, placed along the inferior
+border of the great gluteal, a fleshy fasciculus, separated from
+this muscle by a slight interspace. This fasciculus, long and
+narrow, takes origin from the summit of the sacrum, or
+the coccyx, and goes to partake of the femoral insertions
+of the muscle which it accompanies. We further note a
+muscle of the same kind, and presenting the same aspect,
+which comes from the tuberosity of the ischium. Notwithstanding
+the difference which exists, it is this abnormal
+fasciculus of man which in the quadrupeds here studied is
+considered as constituting the posterior portion of the great
+gluteal.</p>
+
+<p>Bourgelat, considering this posterior portion as belonging
+to the biceps cruris, to which, it is true, it adheres, forms
+of them a muscle which he designates under the name of
+the <i>long vastus</i>. The anterior fasciculus of this long vastus
+is none other than the posterior portion of the great gluteal
+which we have just been studying.</p>
+
+<h5><a name="ThighMuscles" id="ThighMuscles"></a>Muscles of the Thigh</h5>
+
+<p>These muscles are divided into three regions: posterior,
+anterior, and internal.</p>
+
+<p>In a corresponding manner to that which we described
+in connection with the arm, the thigh is applied to the side
+of the trunk, and is free, more or less, only at the level of
+the inferior part.</p>
+
+<p>Further, by reason of this shortening of the femur, the
+great gluteal muscle, which is elongated in the ox and the
+horse, for example, occupies in part the region corresponding<span class="pagenum"><a name="Page_205" id="Page_205">[205]</a></span>
+to that which in man is occupied by the muscles of the
+thigh, which here are reduced in length. In other words,
+they are not superposed, as in the human species, but
+juxtaposed. This is what we will verify further on.</p>
+
+<p>The thigh, as a whole, is flattened from without inwards,
+its transverse diameter being less in extent than its antero-posterior.
+Its external surface is slightly rounded; that
+is, of course, in quadrupeds with sufficiently well-developed
+muscles. Its internal surface is known as the <i>flat of the
+thigh</i>.</p>
+
+<h5>Muscles of the Posterior Region</h5>
+
+<p>It is not unprofitable to recall to mind what muscles
+form the superficial layer of this region in the human being.
+They are the biceps cruris, semi-tendinosus, and semi-membranosus.
+We now proceed to discover their analogues
+in quadrupeds.</p>
+
+<p><b>Biceps Cruris</b> (<a href="#Fig068">Fig. 68</a>, 30; <a href="#Fig069">Fig. 69</a>, 27; <a href="#Fig070">Fig. 70</a>,
+36).&mdash;It is this which, according to Bourgelat, forms the
+central and posterior portions of the long vastus muscle
+which we have mentioned above.</p>
+
+<p>We know that the biceps of man is so named from
+the two portions which form its upper part. In domestic
+quadrupeds, and also in the majority of the mammals, this
+muscle is reduced to a single portion, that which comes from
+the pelvis. It is therefore the portion which arises from
+the femur which does not exist. This condition is sometimes
+found as an abnormality in the human species.</p>
+
+<p>The biceps arises from the tuberosity of the ischium;
+hence it is directed, widening as it goes, towards the leg,
+where it terminates by an aponeurosis which blends with
+the fascia lata and the aponeurosis of the leg, and then proceeds
+to be attached to the anterior border or crest of the
+tibia. By its inferior portion it limits externally the posterior
+region of the knee&mdash;the popliteal space.</p>
+
+<p>A fibrous intersection traverses the biceps in its whole
+length, with the result that the muscle looks as if formed of
+two portions, one of which is situated in front of the other.</p>
+
+<p><span class="pagenum"><a name="Page_206" id="Page_206">[206]</a></span>In the dog and the cat it also arises from the sacro-sciatic
+ligament. At this level its contour is distinguishable from
+that which corresponds to the gluteal muscles, so that we
+there find two prominences one above the other. The
+superior is formed by the gluteal muscles; the inferior corresponds
+to the tuberosity of the ischium. The two prominences
+are separated by a depression, from which the
+biceps emerges. We draw attention to this form, the
+character of which is so expressive of energy in the carnivora.</p>
+
+<p>In these animals the biceps is inserted, by its anterior
+fibres, into the articulation of the knee, while in the rest of
+its extent it covers in great measure by its aponeurosis the
+external aspect of the leg.</p>
+
+<p>In the pig, the biceps is but slightly marked off from
+the posterior part of the great gluteal. In the ox, the
+division between these two muscles is a little more distinct.</p>
+
+<p>In the horse, the sciatic origin of the biceps is covered by
+the semi-tendinosus, so that it only becomes free lower
+down, to appear in the space limited behind by the semi-tendinosus,
+and in front by the posterior part of the gluteus
+maximus.</p>
+
+<p>When the biceps contracts, taking its fixed point from
+above, it flexes the leg and helps to extend the thigh. If,
+on the other hand, it takes its fixed point from below, it
+lowers the ischium, makes the pelvis undergo a see-saw
+movement, and acts thus in the movement of rearing. It
+is sometimes called, on account of one of its actions,
+and the position which it occupies, the &#8216;external flexor, or
+peroneal muscle of the leg.&#8217;</p>
+
+<p><b>Semi-tendinosus</b> (<a href="#Fig068">Fig. 68</a>, 31; <a href="#Fig070">Fig. 70</a>, 37; <a href="#Fig087">Fig. 87</a>, 1;
+<a href="#Fig088">Fig. 88</a>, 1; <a href="#Fig089">Fig. 89</a>, 28).&mdash;This muscle forms the contour of
+the thigh posteriorly, so that when the latter is viewed from
+the side, it is the semi-tendinosus above all that forms the
+outline. But, as we shall soon see, it is in this case more
+distinct above than below, because of the deviation which it
+undergoes in order to occupy by its inferior part the
+internal side of the leg.</p>
+
+<p>In the dog, the cat, and the ox, the semi-tendinosus<span class="pagenum"><a name="Page_207" id="Page_207">[207]</a></span>
+arises from the tuberosity of the ischium only, as in the
+human species. In the pig, it also takes origin higher up
+from the sacro-sciatic ligament and the coccygeal aponeurosis.
+In the horse, it extends still further, for it is also
+attached to the crest of the sacrum.</p>
+
+<p>The indication of these origins is of importance from the
+point of view of external form, and to convince ourselves of
+this it is sufficient to compare, in the ox and the horse, the
+region of the pelvis situated below the root of the tail. In
+the ox, whose semi-tendinosus arises from the tuberosity
+of the ischium only, this region is depressed, and the cavity
+which is formed at this level is limited behind by the tuberosity,
+which we know is very thick and prominent above.
+This causes the superior part of the crupper to be less
+oblique than in the horse. This characteristic is more
+especially marked in the cow, the bull having this region of
+a more rounded form.</p>
+
+<p>In the horse, on account of the semi-tendinosus ascending
+to the coccyx, and even to the sacrum, the depression in
+question does not exist, and the presence of the tuberosity
+of the ischium is only slightly revealed.</p>
+
+<p>Descending from the origin indicated above, and inclining
+more and more inwards, the semi-tendinosus proceeds to
+blend with the aponeurosis of the leg, to be inserted into
+the anterior border of the tibia, after crossing over the
+internal surface of the latter. It forms the internal boundary
+of the popliteal space.</p>
+
+<p>When this muscle contracts, taking its fixed point at the
+pelvis, it flexes the leg. If, on the other hand, it takes its
+fixed point at the tibia, it makes the pelvis describe a see-saw
+movement, and acts accordingly in the movement of
+rearing.</p>
+
+<p>It is sometimes named the &#8216;internal or tibial flexor of the
+leg,&#8217; in opposition to the crural biceps, which, as stated above,
+is then the external flexor of the same region.</p>
+
+<p><b>Semi-membranosus</b> (<a href="#Fig068">Fig. 68</a>, 32; <a href="#Fig087">Fig.
+87</a>, 2; <a href="#Fig088">Fig. 88</a>, 2).&mdash;This
+muscle, situated on the inner side of the semi-tendinosus,
+can be seen only when the thigh is regarded on
+its posterior aspect.</p>
+
+<p><span class="pagenum"><a name="Page_208" id="Page_208">[208]</a></span>It is only by reason of the homology of situation with
+the corresponding muscle in man that we give the name
+under which we are studying it; indeed, its structure is
+different, for it does not present the long, broad, aponeurotic
+tendon which, in its superior part, characterizes this muscle
+in the human species.</p>
+
+<p>It arises above from the inferior surface of the ischium,
+and from the tuberosity of the same bone. In the pig,
+and especially in the horse, it passes further upwards, to
+arise from the aponeurosis of the coccygeal muscles. So
+that if we compare it with that of the ox, which does not
+extend beyond the ischium, we find that it is associated
+with the semi-tendinosus in determining the difference of
+aspect to which we have already called attention in connection
+with the region of the pelvis situated below the root of
+the tail.</p>
+
+<p>The semi-membranosus is then directed downwards and
+forwards, to take its place on the internal surface of the
+thigh, where it is partly covered by the gracilis muscle.
+It is inserted in the following manner:</p>
+
+<p>In the dog and the cat it is divided into two parts,
+anterior and posterior. The first, the more developed, is
+attached to the internal surface of the inferior extremity
+of the femur; the second to the internal tuberosity of the
+tibia.</p>
+
+<p>The same arrangement occurs in the ox.</p>
+
+<p>In the horse it is inserted into the internal surface of the
+internal condyle of the femur.</p>
+
+<p>The semi-membranosus is an extensor of the thigh when
+it takes its fixed point at the pelvis; it is also an adductor
+of the lower limb. If it takes its fixed point below it assists
+in the action of rearing.</p>
+
+<p>It is now necessary for us, especially as regards the horse,
+to add some indications relative to the exterior forms of
+the region constituted by the semi-membranosus and semi-tendinosus.
+These two muscles form, by their union, a
+surface contour, slightly projecting and of elongated form,
+which occupies the posterior border of the thigh, the
+contour corresponding to the region known as the <i>buttock</i>, in<span class="pagenum"><a name="Page_209" id="Page_209">[209]</a></span>
+spite of the fact that none of the gluteal muscles take any
+part in the structure of this region. But the appearances,
+to a certain extent, justify the preservation of this name.
+Indeed, because of the groove which separates the gluteal
+region of one side from that of the opposite side, and
+from the position of the anal orifice in the superior part of
+this groove, we may admit the name which, in hippology,
+has been given to this part of the thigh.</p>
+
+<p>In addition to the reasons just given, and which are
+justified especially by the position occupied by the muscular
+mass formed by the union of the two muscles, there is
+another which, this time, has a relation to a certain
+detail of form. In the superior part of the convexity,
+which the gluteal region describes in the greater part of its
+extent, there is found a more salient point, greatly accentuated
+in lean animals, due to the presence of the tuberosity
+of the ischium; it is the <i>point</i> or <i>angle of the buttock</i>. At
+this level, and near the median line, the semi-membranosus,
+not aponeurotic, but fleshy, and even thicker there than
+anywhere else, sometimes produces a sharply localized
+prominence. And as this prominence is situated on the
+outer side of the anal orifice, the resemblance to a small
+&#8216;buttock&#8217; is still more marked.</p>
+
+<p>In lean horses a deep groove separates the mass formed
+by the semi-membranosus and semi-tendinosus from that
+of the other muscles of the thigh situated more in front;
+this groove is known by a name which in this case is
+remarkably expressive&mdash;that of the &#8216;line of poverty.&#8217;</p>
+
+<p>If we examine the gluteal region as a whole by looking
+at the thigh from the side, we plainly see the graceful
+curve produced by the general convexity above indicated.
+We return to this point, in order to add that, in its lower
+part, this curve alters its character; that is to say, it
+is replaced by a slight concavity. This, which is designated
+under the name of <i>the fold of the buttock</i>, is situated close to
+the level of articulation of the leg with the thigh-bone.</p>
+
+<p class="pagenum"><a name="Page_210" id="Page_210">[210]</a></p>
+
+<h5>Muscles of the Anterior Region</h5>
+
+<p>First we recall that in man the anterior muscles of the
+thigh are: the triceps cruris, the tensor of the fascia lata,
+and the sartorius.</p>
+
+<p><b>Triceps Cruris</b> (<a href="#Fig008">Fig. 8</a>, 36; <a href="#Fig069">Fig. 69</a>, 31; <a href="#Fig070">Fig. 70</a>, 41;
+<a href="#Fig084">Fig. 84</a>, 2; <a href="#Fig087">Fig. 87</a>, 3; <a href="#Fig088">Fig. 88</a>, 3).&mdash;This muscle, which
+occupies the greater part of the space between the pelvis
+and the anterior aspect of the femur, consists of three parts:
+an external, or vastus externus; an internal, or vastus internus;
+and a median or long portion, or rectus femoris.
+This division accordingly recalls that which characterizes
+the human triceps cruris. Furthermore, as in the case
+of the latter, the vastus externus and the vastus internus
+take their origin from the shaft of the femur, while
+the long portion arises from the pelvis. The <i>vastus
+externus</i> arises from the external lip of the linea aspera
+of the femur (or from the external border of the posterior
+surface of this bone in the ox and the horse, in
+which the linea aspera, considerably widened, especially
+in the latter, forms a surface), and from the external surface
+of the shaft of the femur. From this origin its fibres
+pass downwards and forwards, to be inserted into the tendon
+of the long portion of the muscle and into the patella.</p>
+
+<p>In the dog and the cat the vastus externus is the most
+voluminous of the three portions which constitute the
+triceps muscle. It is covered by the fascia lata; but notwithstanding
+this, its presence is revealed by a prominence
+which occupies the external surface of the thigh, and
+surmounts, in the region of the knee, the more slightly
+developed one which is produced by the knee-cap.</p>
+
+<p>The <i>vastus internus</i>, situated on the inner surface of the
+thigh, takes its origin from the corresponding surface of
+the femur, and proceeds towards the patella.</p>
+
+<p>The rectus femoris arises from the iliac bone, above the
+cotyloid cavity; its fleshy body, which is fusiform, and
+situated in front of and between the two vasti muscles, is
+directed towards the patella, into which it is inserted by
+a tendon, which receives the other two portions.</p>
+
+<p><span class="pagenum"><a name="Page_211" id="Page_211">[211]</a></span>It is covered in front by the tensor of the fascia lata, and
+contributes with the vastus externus to form the upper
+prominence of the knee.</p>
+
+<p>The ligamentous fibres, which, as in man, unite the knee-cap
+to the tibia, transmit to this latter the action determined
+by the contraction of the triceps. This muscle is an extensor
+of the leg. Furthermore, the rectus femoris, or long
+portion, acts as a flexor of the thigh.</p>
+
+<p><b>Tensor Fascia Lata</b> (<a href="#Fig068">Fig. 68</a>, 34, 36; <a href="#Fig069">Fig. 69</a>, 30, 31;
+Fig. 70, 40).&mdash;This muscle, generally larger in quadrupeds
+than in man, is flat and triangular, and occupies the superior
+and anterior part of the thigh.</p>
+
+<p>It arises from the anterior iliac spine (inferior in carnivora,
+external in the ox and the horse); it is prolonged downwards
+by an aponeurosis (fascia lata) which occupies the
+external aspect of the thigh, proceeds to be inserted into
+the patella and blend with the aponeurosis of the biceps
+muscle.</p>
+
+<p>It covers the rectus and vastus externus portions of
+the triceps cruris; it is also in relation with the gluteal
+muscles.</p>
+
+<p>The tensor of the fascia lata flexes the thigh, and serves to
+raise the lower limb as a whole.</p>
+
+<p><b>Sartorius</b> (<a href="#Fig068">Fig. 68</a>, 35; <a href="#Fig087">Fig. 87</a>, 4, 5; <a href="#Fig088">Fig. 88</a>, 5).&mdash;This
+muscle, long and flattened, is called by veterinarians
+<i>the long adductor of the leg</i>.</p>
+
+<p>Before beginning the study of its position in quadrupeds,
+it is necessary to remember that in man, where
+the thigh has a form almost conical, the sartorius commences
+on the anterior face of this latter, and is directed
+downwards and inwards to reach the internal surface of
+the knee.</p>
+
+<p>But now let us suppose the thigh flattened from without
+inwards; there will evidently result from this a change in
+situation with regard to the muscle in question. In fact,
+when this supposition is admitted, it is easy to imagine
+that in a great part of the extent in which the sartorius
+is normally anterior it will become internal. This is why,
+these conditions being realized in quadrupeds, we shall<span class="pagenum"><a name="Page_212" id="Page_212">[212]</a></span>
+find that, in some of them, the sartorius is situated on the
+aspect of the thigh which is turned to the side of the
+trunk.</p>
+
+<p>In the dog and the cat it arises from the anterior iliac
+spine, and from the half of the border of the bone situated
+immediately below it; but the fibres from this second
+origin being hidden by the tensor of the fascia lata, on the
+inner side of which they are situated, viewing the external
+surface of the thigh, the muscle seems to arise from the
+iliac spine only.</p>
+
+<p>The sartorius in these animals is divided into two parts,
+which, in general, are placed in contact. One of these
+fasciculi is anterior; the other is situated further back. The
+first is visible on the anterior border of the thigh, in front
+of the tensor of the fascia lata, but below it inclines inwards;
+in its superior part also, a small extent of the internal surface
+is occupied by it. The second, which, as we have said,
+is situated further back, belongs wholly to the inner surface
+of the thigh; it is this portion which arises from the inferior
+border of the ilium (this is the homologue of the anterior
+border of the human iliac bone).</p>
+
+<p>The two fasciculi then pass towards the knee, being in
+relation with the rectus and the vastus internus of the triceps.
+The anterior fasciculus is inserted into the patella.
+The posterior unites with the tendons of the gracilis (see
+below) and semi-tendinosus, and then proceeds to be inserted
+into the superior part of the internal surface of the
+tibia.</p>
+
+<p>On account of their different insertions these two parts
+receive the names of <i>the patellar sartorius</i> and <i>tibial sartorius</i>
+respectively.</p>
+
+<p>In the ox and the horse the sartorius is still more definitely
+situated on the internal surface of the thigh. Consisting of
+a single fasciculus, representing the tibial sartorius of the
+cat and the dog, it arises in the abdominal cavity from the
+fascia covering the iliac muscle, then passes under the
+crural arch, and terminates, by an aponeurosis which blends
+with that of the gracilis, on the inner fibres of the patellar
+ligament. In short, the sartorius is of interest to us in the<span class="pagenum"><a name="Page_213" id="Page_213">[213]</a></span>
+carnivora only, and especially on account of its anterior or
+patellar fasciculus.</p>
+
+<p>It is an adductor of the leg and a flexor of the thigh.</p>
+
+<h5>Muscles of the Internal Region</h5>
+
+<p>The ilio-psoas pectineus and the adductors which we study
+in man, in connection with the internal aspect of the thigh,
+offer little of interest from the point of view of external form
+in quadrupeds; it is for this reason that we will disregard
+them.</p>
+
+<p>The gracilis alone merits description.</p>
+
+<p><b>Gracilis</b> (<a href="#Fig087">Fig. 87</a>, 9; <a href="#Fig088">Fig. 88</a>, 6).&mdash;Designated in veterinary
+anatomy under the name of <i>the short adductor of the leg</i>,
+this muscle, expanded in width, occupies the greater part
+of the internal surface of the thigh, <i>or flat of the thigh</i>, as
+this region is also called. Let us imagine, in man, the
+internal surface of the thigh broader, and the internal
+rectus more expanded, and we shall have an idea of the
+same muscle as it exists in quadrupeds.</p>
+
+<p>The gracilis arises from the ischio-pubic symphysis
+and from the neighbouring regions; thence it is directed
+towards the leg to be inserted into the superior part of the
+internal surface of the tibia, after being united to the tendons
+of the sartorius and semi-tendinosus. We find, accordingly,
+at this level, an arrangement which recalls the general appearance
+of what in man receives the name of <i>the goose&#8217;s
+foot</i> (<i>pes anserinus</i>).</p>
+
+<p>It is between this muscle and the sartorius, at the superior
+part of the internal surface of the thigh, in the region which
+recalls the triangle of Scarpa, that we are able, especially in
+the cat and the dog, to see the adductor muscles of the
+thigh. We also partly see there, in these animals, the
+vastus internus and the rectus of the triceps (see <a href="#Fig087">Fig. 87</a>).
+The gracilis is an adductor of the thigh.</p>
+
+<h5>Muscles of the Leg</h5>
+
+<p>We will divide the leg into three regions: anterior,
+external, and posterior. With regard to the internal region,<span class="pagenum"><a name="Page_214" id="Page_214">[214]</a></span>
+there are no muscles which belong exclusively to it; for it
+is in great measure formed by the internal surface of the
+tibia, which, as in man, is subcutaneous.</p>
+
+<h5>Muscles of the Anterior Region</h5>
+
+<p>We first note that in the human species the tibialis
+anticus, extensor proprius pollicis, extensor longus digitorum
+and the peroneous tertius or anticus, form the subcutaneous
+layer of this region. We now proceed to study these muscles
+in quadrupeds.</p>
+
+<div class="figmed"><a name="Fig083" id="Fig083"></a>
+<img src="images/illo237.png" alt="Fig. 83" width="250" height="483" />
+<p class="caption just">Fig. 83.&mdash;Myology of the Horse: the Anterior Tibial Muscle
+(Flexor of the Metatarsus), Left Leg, Anterior View.</p>
+
+<p class="subcaption just">1, Femoral trochlea; 2, tibia; 3, tendinous portion of the tibialis
+anticus; 4, cuboid branch of same; 5, 5, its metatarsal branch; 6, fleshy
+portion; 7, cuneiform branch of its tendon; 8, metatarsal branch of
+the same tendon; 9, extensor longus digitorum (anterior extensor of
+the phalanges turned outwards); 10, peroneus brevis (lateral extensor
+of the phalanges).</p></div>
+
+<p><b>Tibialis Anticus</b> (<a href="#Fig083">Fig. 83</a>; <a href="#Fig084">Fig. 84</a>, 6;
+<a href="#Fig085">Fig. 85</a>, 4; <a href="#Fig087">Fig. 87</a>, 10;
+<a href="#Fig088">Fig. 88</a>, 10, 11).&mdash;It is further named by veterinarians the
+<i>flexor of the metatarsus</i>.</p>
+
+<p><span class="pagenum"><a name="Page_215" id="Page_215">[215]</a></span>In the dog and the cat this muscle, which is rather large,
+arises from the external tuberosity of the tibia and from the
+crest of this bone. In its superior part it is flat, but lower
+down it is thick and produces a prominence in front of the
+tibia. Finally, it becomes tendinous, and passes towards
+the tarsus; thence it is directed towards the inner side of
+the metatarsus, and is inserted into the great-toe, this latter
+being sometimes well developed, but also often merely represented
+by a small bony nodule on which the muscle is then
+fixed.</p>
+
+<p>In the other animals with which we here occupy ourselves,
+the tibialis anticus presents a complexity which would be
+incomprehensible unless this muscle be first studied in
+the horse.</p>
+
+<p>In this latter the tibialis anticus consists of two distinct
+portions, placed one in front of the other: a fleshy portion,
+and a tendinous portion running parallel to it.</p>
+
+<p>The muscle is covered, except on its internal part and
+inferiorly, by a muscle with which we will occupy ourselves
+later on&mdash;that is, the common extensor of the toes.</p>
+
+<p>The tendinous portion of the tibialis anticus (<a href="#Fig083">Fig. 83</a>),
+especially covered by the extensor of the toes, arises from
+the inferior extremity of the femur, from the fossa situated
+between the trochlea and the external condyle; thence it
+descends towards a groove which is hollowed out on the
+external tuberosity of the tibia, and is directed towards the
+tarsus, where it divides into two branches, which are
+inserted into the cuboid bone and the superior extremity of
+the principal metatarsal. These two parts form a ring
+through which the terminal tendon of the fleshy portion of
+the same muscle passes.</p>
+
+<p>This fleshy portion, situated behind the preceding, arises
+from the superior extremity of the tibia, on the borders of
+the groove in which the tendinous portion lies; thence it
+passes downwards for a short distance on the inner side of
+the common extensor of the toes, which covers it in the rest
+of its extent. It ends in a tendon which, after passing
+through the tendinous ring above noticed, divides into
+two branches. One of these branches is inserted into
+the anterior surface of the superior extremity of the principal
+metatarsal, the other into the second cuneiform bone.</p>
+
+<p class="pagenum"><a name="Page_216" id="Page_216">[216]</a></p>
+
+<div class="figmed"><a name="Fig084" id="Fig084"></a>
+<img src="images/illo239.png" alt="Fig. 84" width="300" height="520" />
+<p class="caption just">Fig. 84.&mdash;Myology of the Dog: Left Hind-limb, External Aspect.</p>
+
+<p class="subcaption just">1, Biceps cruris and fascia lata, divided in order to expose the upper
+part of the muscles of the leg; 2, inferior portion of the triceps cruris;
+3, patella; 4, semi-tendinosus; 5, inferior extremity of the femur; 6,
+tibialis anticus (flexor of the metatarsus); 7, extensor longus digitorum
+(anterior extensor of the phalanges); 8, tibia; 9, peroneus longus; 10,
+peroneus brevis; 11, fifth metatarsal; 12, fasciculus detached from the
+peroneus brevis and passing towards the fifth toe; 13, external head of
+gastrocnemius; 14, tendo-Achillis; 15, calcaneum; 16, flexor digitorum
+sublimis; 17, 17, tendon of the flexor digitorum sublimis; 18, flexor longus
+pollicis (portion of the deep flexor of the toes); 19, dorsal muscle of the
+foot (short extensor of the toes).</p></div>
+
+<p><span class="pagenum"><a name="Page_217" id="Page_217">[217]</a></span></p><p>In the ox the same two portions of the tibialis anticus
+exist, but with this capital difference&mdash;that the anterior
+portion is fleshy, superficial, and blended for a great part of
+its length with the common extensor of the toes.</p>
+
+<p>The portion which corresponds to that which is fleshy in
+the horse arises from the tibia; below, it ends on the inner
+surface of the superior extremity of the metatarsus and the
+cuneiform bones. That which represents the tendinous
+part, which is also fleshy, as we have just pointed out,
+arises above with the common extensor of the toes, from
+the femur, in the fossa situated between the trochlea and
+the external condyle; whilst below, after having given
+passage to the tendon of the preceding portion, as in the
+horse, it is inserted into the metatarsus and the cuneiform
+bones.</p>
+
+<p>In the pig, the tibialis anticus presents an arrangement
+nearly similar to that which we have just described.</p>
+
+<p>It seems to us of interest to add that it has been sought
+to ascertain to what muscle of the human leg the tendinous
+part of the tibialis of the horse corresponds&mdash;a part which
+has become fleshy in the pig and the ox.</p>
+
+<p>According to some authors, it represents the peroneus
+tertius; but that muscle is situated on the outer side of
+the common extensor of the toes; and here the portion with
+which it has been compared is placed on the inside. It has
+also been likened to a portion of the common extensor
+of the toes, but it does not pass to the latter. Lastly, it has
+been considered as being the homologue of the proper
+extensor of the great-toe; but why, then, in the ox, which
+has no great-toe, is it so highly developed? Nevertheless,
+its position and its relations sufficiently warrant this method
+of comprehending it. The tibialis anticus is a flexor of the
+foot. It is also able, in animals in which the tarsal articulations
+allow of the movement, to rotate the foot inwards.</p>
+
+<p class="pagenum"><a name="Page_218" id="Page_218">[218]</a></p>
+
+<div class="figmed"><a name="Fig085" id="Fig085"></a>
+<img src="images/illo241.png" alt="Fig. 85" width="350" height="523" />
+<p class="caption just">Fig. 85.&mdash;Myology of the Ox: Left Leg, External Aspect.</p>
+
+<p class="subcaption just">1, Gluteus maximus and biceps cruris; 2, semi-tendinosus; 3, patella;
+4, tibialis anticus (flexor of the metatarsus); 5, extensor longus digitorum
+(anterior extensor of the phalanges); 6, fasciculus of the extensor longus
+digitorum, which is considered as the representative of the tendinous
+portion of the tibialis anticus in the horse; 7, peroneus longus; 8,
+peroneus brevis (proper extensor of the external toe); 9, external head
+of gastrocnemius; 10, soleus; 11, tendo-Achillis; 12, calcaneum; 13,
+tendon of the extensor longus digitorum (superficial flexor of the phalanges);
+14, flexor longus pollicis and tibialis posticus (deep flexor of the
+phalanges); 15, tendon of the superficial flexor of the toes; 16, tendon of
+the deep flexor of the toes; 17, suspensory ligament of the fetlock.</p></div>
+
+<p>With regard to the tendinous part, called by veterinarians
+the <i>cord of the flexor of the metatarsus</i>, it serves, in
+the horse, to produce the flexion of the metatarsus when<span class="pagenum"><a name="Page_219" id="Page_219">[219]</a></span>
+the knee is already flexed; it thus acts in a passive fashion,
+which is explained by its resistance and the position which
+it occupies in relation to these two articulations.</p>
+
+<p><b>Extensor Proprius Pollicis.</b>&mdash;This muscle exists only in
+the dog and the cat, and there in a rudimentary condition.</p>
+
+<p>It is covered by the common extensor of the toes and the
+tibialis anticus, and passes, accompanied by the tendon of
+this latter muscle, to terminate on the second metatarsal,
+or the phalanx, which articulates with it. When the first
+toe exists in the dog, it is inserted into this by a very
+slender tendon.</p>
+
+<p><b>Extensor Longus Digitorum</b> (<a href="#Fig083">Fig. 83</a>, 9; <a href="#Fig084">Fig. 84</a>, 7;
+<a href="#Fig085">Fig. 85</a>, 5, 6; <a href="#Fig086">Fig. 86</a>, 4; <a href="#Fig087">Fig. 87</a>,
+12; <a href="#Fig088">Fig. 88</a>, 7).&mdash;It is also
+called by veterinarians <i>the anterior extensor of the phalanges</i>.</p>
+
+<p>In the dog and the cat this muscle is to be seen in the
+space limited behind by the peroneus longus and in front by
+the tibialis anticus. Above it is covered by this latter. In
+the lower half of the leg, it is also in relation, on the inner
+side, with the tibialis anticus; but behind it is separated
+from the peroneus longus by the external surface of the
+shaft and inferior extremity of the tibia. This arrangement,
+besides, recalls that which is found in man, the
+peroneus longus of the latter diverging in the same way, at
+this level, from the common extensor, and leaving exposed
+the corresponding portion of the skeleton of the leg.</p>
+
+<p>This muscle, fusiform in shape, arises at its upper part
+from the external surface of the inferior extremity of the
+femur, then its tendon passes into a groove hollowed on
+the external tuberosity of the tibia. The fleshy body which
+succeeds is directed towards the tarsus, but before reaching
+it is replaced by a tendon. This tendon, at the level of the
+metatarsal bones, divides into four slips, which pass towards
+the toes, and are inserted into the second and third
+phalanges of the latter.</p>
+
+<p>In the horse it covers, to a great extent, the tibialis
+anticus, so that it is the latter which forms the large fusiform
+prominence especially noticeable in the middle region,
+to which the contour of the anterior surface of the leg
+is due.</p>
+
+<p class="pagenum"><a name="Page_220" id="Page_220">[220]</a></p>
+
+<div class="figmed"><a name="Fig086" id="Fig086"></a>
+<img src="images/illo243.png" alt="Fig. 86" width="300" height="533" />
+<p class="caption just">Fig. 86.&mdash;Myology of the Horse: Left Hind-limb, External Aspect.</p>
+
+<p class="subcaption just">1, Semi-tendinosus; 2, biceps cruris; 3, patella; 4, extensor longus
+digitorum (anterior extensor of the phalanges); 5, reinforcing band arising
+from the ligament of the fetlock; 6, peroneus brevis (lateral extensor of
+the phalanges); 7, external head of gastrocnemius; 8, soleus; 9, tendo-Achillis;
+10, calcaneum; 11, tendon of the superficial flexor of the toes
+(superficial flexor of the phalanges); 12, flexor longus pollicis and tibialis
+posticus (deep flexor of the phalanges); 13, 13, tendon of the superficial
+flexor of the phalanges; 14, 14, tendon of the deep flexor of the phalanges;
+15, suspensory ligament of the fetlock; 16, principal metatarsal: 17,
+external rudimentary metatarsal.</p></div>
+
+<p><span class="pagenum"><a name="Page_221" id="Page_221">[221]</a></span>It arises above from the inferior extremity of the femur,
+from the fossa situated between the trochlea and the external
+condyle; therefore, it has a common origin with the
+tendinous portion of the tibialis anticus, or flexor of the
+metatarsus.</p>
+
+<p>The tendon, which at the level of the inferior part of
+the leg succeeds to the fleshy body, passes in front of
+the tarsus, the principal metatarsal, and receives the tendon
+of the peroneus brevis which we will describe <a href="#SecPeroneusBrevis">later on</a>.
+It then reaches the anterior surface of the fetlock. There
+it presents an arrangement analogous to that which we
+have pointed out in connection with the anterior extensor
+of the phalanges&mdash;a muscle which, in the fore-limbs, corresponds
+to the common extensor of the digits; that is to say,
+it is inserted, in form of an expansion, into the pyramidal
+prominence of the third phalanx, after having formed
+attachments to the first and second, and having received
+on each side a strengthening band from the suspensory
+ligament of the fetlock.</p>
+
+<p>In the ox the long extensor of the toes is united above,
+and for a great part of its length, with the portion of the
+tibialis anticus, which represents, albeit in the fleshy state,
+the tendinous cord of the latter in the horse.</p>
+
+<p>In common with this portion, it arises from the inferior
+extremity of the femur. Thence it passes towards the tarsus
+and divides into two fasciculi, internal and external, which
+are continued by tendons. These pass towards the
+phalanges, and, in case of the common extensor of the digits
+belonging to the fore-limbs, the internal is destined for the
+internal toe, and the external is common to the two toes.</p>
+
+<p class="pagenum"><a name="Page_222" id="Page_222">[222]</a></p>
+
+<div class="figmed"><a name="Fig087" id="Fig087"></a>
+<img src="images/illo245.png" alt="Fig. 87" width="275" height="544" />
+<p class="caption">Fig. 87.&mdash;Myology of the Dog: Left Hind-limb, Internal Aspect.</p>
+
+<p class="subcaption just">1, Semi-tendinosus; 2, semi-membranosus; 3, triceps cruris (vastus
+internus); 4, sartorius (patellar); 5, sartorius (tibial); 6, patella; 7,
+first or middle adductor; 8, small and great adductor united; 9, gracilis;
+10, tibialis anticus (flexor of the metatarsus); 11, tibia; 12, tendon of
+extensor longus digitorum (anterior extensor of the phalanges): 13, gastrocnemius,
+inner head; 14, tendo-Achillis; 15, calcaneum; 16, popliteus;
+17, superficial flexor of the toes; 18, flexor longus pollicis (portion of the
+deep flexor of the toes); 19, flexor longus digitorum (portion of the deep
+flexor of the toes); 20, tendon of the tibialis posticus.</p></div>
+
+<p class="pagenum"><a name="Page_223" id="Page_223">[223]</a></p>
+
+<div class="figmed"><a name="Fig088" id="Fig088"></a>
+<img src="images/illo246.png" alt="Fig. 88" width="350" height="552" />
+<p class="caption just">Fig. 88.&mdash;Myology of the Horse: Left
+Hind-leg, Internal Aspect.</p>
+
+<p class="subcaption just">1, Semi-tendinosus; 2,
+semi-membranosus; 3, triceps
+cruris (vastus internus); 4,
+patella; 5, sartorius; 6,
+gracilis; 7, extensor longus
+digitorum common extensor
+of the toes (anterior extensor
+of the phalanges);
+8, tendon of the preceding
+muscle; 9, reinforcing
+band given off by the suspensory
+ligament of the
+fetlock; 10, tibialis anticus
+(flexor of the metatarsus),
+its tendinous portion; 11, tibialis anticus (flexor of the metatarsus), its
+fleshy portion; 12, cuneiform branch of the tendon of this fleshy portion;
+13, internal head of gastrocnemius; 14, popliteus; 15, tendon of the flexor
+brevis digitorum (superficial flexor of the phalanges); 16, flexor longus
+pollicis and tibialis posticus (deep flexor of the phalanges); 17, flexor
+longus digitorum (oblique flexor of the phalanges); 18, 18, tendon of the
+superficial flexor of the phalanges; 19, 19, tendon of the deep flexor of
+the phalanges; 20, suspensory ligament of the fetlock; 21, principal
+metatarsal; 22, internal rudimentary metatarsal.</p></div>
+
+<p>In the pig the general arrangement of the muscle is
+similar, but the tendons end in a manner which is a little
+more complicated. Apart from the fasciculi which correspond
+to the tendinous portion of the tibialis anticus
+(fleshy here, as in the ox), the long extensor of the toes
+at the level of the tarsus divides into three tendons: the
+internal goes to the great internal toe; the middle bifurcates
+in the upper part of the digital portion of the foot,
+and each of its branches goes towards one of the great-toes;<span class="pagenum"><a name="Page_224" id="Page_224">[224]</a></span>
+the external divides to pass towards each of the two small
+toes, and towards the great ones; but this latter disposition
+is not constant.</p>
+
+<p>By its contraction the muscle which we have just studied
+extends the phalanges and flexes the foot.</p>
+
+<p><b>Peroneus Tertius.</b>&mdash;This muscle is not found in domestic
+quadrupeds.</p>
+
+<p>We should remember, nevertheless, that certain authors
+consider as representing it the tendinous portion of the
+anterior tibial of the horse, or the corresponding portion
+now fleshy, of the same muscle in the pig and the ox. It
+is by reason of this fact that it is called the third peroneal,
+notwithstanding that in the numerical order of the peroneals
+it is rather the first.</p>
+
+<p>But that which still further complicates this question of
+nomenclature is that some authors give this name of third
+to a peroneal which, in the carnivora, is situated more definitely
+in the group of external muscles (see <a href="#SecPeroneusBrevis">below</a>, <b>Short
+Lateral Peroneal</b>).</p>
+
+<h5>Muscles of the External Region</h5>
+
+<p>In man, two muscles constitute this region; they are
+the peroneus longus and peroneus brevis.</p>
+
+<p><b>Peroneus Longus</b> (<a href="#Fig084">Fig. 84</a>, 9; <a href="#Fig085">Fig. 85</a>, 7).&mdash;This muscle
+does not exist in the domestic animals; only in the flesh-eaters,
+the pig and the ox excepted.</p>
+
+<p>It is in relation superiorly with the tibialis anticus, and
+inferiorly with the common extensor of the toes; in the
+ox, it is in contact with this latter muscle throughout its
+whole length.</p>
+
+<p>The peroneus longus arises from the external tuberosity
+of the tibia; towards the middle of the leg it is replaced by
+a tendon. This proceeds towards the tarsus, but previously
+it passes between the tibia and fibula. In the ox it is
+situated in front of the coronoid tarsal bone; we recollect
+that this bone is regarded as representing the inferior
+extremity of the fibula (see <a href="#Page_97">p. 97</a>). Then it passes
+into a groove belonging to the cuboid bone or to the cuboido-scaphoid
+bone in the ox, traverses obliquely the posterior<span class="pagenum"><a name="Page_225" id="Page_225">[225]</a></span>
+aspect of the tarsus, and is inserted into the rudimentary
+bone which represents the first toe; or, if this does not exist,
+into the innermost of the metatarsal bones.</p>
+
+<p>This muscle is an extensor of the foot. It also rotates it
+outwards in the animals in which the articulation permits
+this latter movement.</p>
+
+<p><a name="SecPeroneusBrevis" id="SecPeroneusBrevis"></a><b>Peroneus Brevis</b>
+(<a href="#Fig083">Fig. 83</a>, 8; <a href="#Fig083">Fig. 83</a>, 10; <a href="#Fig084">Fig. 84</a>, 10;
+<a href="#Fig086">Fig. 86</a>, 6).&mdash;In the dog and the cat, this muscle is covered
+in part by the peroneus longus, and arises from the inferior
+half of the tibia and the fibula; at the level of the tarsus it
+becomes tendinous, passes into a groove hollowed out on the
+external surface of the inferior extremity of the fibula, and
+terminates on the external aspect of the superior extremity
+of the fifth metatarsal. A little before this insertion it
+crosses the tendon of the long peroneal in passing to the
+outer side of the latter.</p>
+
+<p>To the short peroneal muscle is found annexed a very
+thin fasciculus which lies upon it. This fasciculus arises
+from beneath the head of the fibula, and is soon replaced
+by a thin tendon, which, accompanying that of the short
+peroneal, proceeds towards the foot, after having traversed
+the groove in the inferior extremity of the fibula; passes
+along by the fifth metatarsal (<a href="#Fig084">Fig. 84</a>, 12); blends at the
+level of the first phalanx of the fifth toe with the corresponding
+tendon of the long extensor of the toes, and partakes
+of the insertions of this tendon.</p>
+
+<p>This fasciculus is designated by some authors under the
+name of the peroneal of the fifth toe, or the proper extensor
+of the same toe. But what makes still further complications
+is that other authors regard it as an anterior, or third,
+peroneal. Now, these names are those which other anatomists
+have applied to the fasciculus of the anterior tibial,
+which, in the pig and the ox, is fused in part with the
+long extensor of the toes. Hence there results a confusion
+which is truly regrettable.</p>
+
+<p>In brief, we can, without inconvenience, consider it as a
+fasciculus of the short peroneal muscle.</p>
+
+<p>We sometimes find in man, but abnormally, an arrangement
+which partly recalls that which we have just indicated.<span class="pagenum"><a name="Page_226" id="Page_226">[226]</a></span>
+It consists in a duplication of the tendon of the short peroneal,
+one of the branches of which goes to the fifth metatarsal,
+and the other to the fifth toe; it is sometimes a single
+fasciculus which goes to the phalanges of this latter. We
+have met with examples of these anomalies.<a name="FNanchor_31_31"
+id="FNanchor_31_31"></a><a href="#Footnote_31_31" class="fnanchor">[31]</a> In the pig,
+the short peroneal is situated on the same plane as the long.
+It consists of two clearly distinct fasciculi, which arise from
+the fibula. The tendon of the anterior fasciculus proceeds
+to the great external toe&mdash;that is to say, the fourth, of
+which it is the proper extensor. The posterior fasciculus
+terminates on the small external toe, the fifth, of which it
+is in like manner the extensor.</p>
+
+<div class="footnote"><p><a name="Footnote_31_31" id="Footnote_31_31"></a><a href="#FNanchor_31_31"><span
+class="label">[31]</span></a> &Eacute;douard Cuyer, &#8216;Anomalies, Osseous and Muscular&#8217; (<i>Bulletins de la
+Soci&eacute;t&eacute; d&#8217;Anthropologie</i>, Paris, 1891).</p></div>
+
+<p>In the ox, the fleshy fibres of the short peroneal arise from
+a fibrous band which replaces the fibula, and from the external
+tuberosity of the tibia. Situated behind the long
+peroneal and on the same plane, it terminates in a tendon
+which appears at the level of the inferior part of the leg; it
+passes in front of the canon, and is inserted into the external
+toe, of which it is the proper extensor.</p>
+
+<p>In the horse, it is the sole representative of the peroneal
+muscles, and veterinary anatomists have given it the name
+of <i>the lateral extensor of the phalanges</i>.</p>
+
+<p>Its fleshy body arises above from the external lateral
+ligament of the knee-joint, and from the whole length of the
+fibula. In the middle third of the leg it is narrowed;
+lower down it is replaced by a tendon. This is lodged in
+a groove hollowed on the external surface of the inferior
+extremity of the tibia; then after passing along the external
+surface of the tarsus, it is directed forward, and proceeds to
+blend towards the middle of the canon-bone with the tendon
+of the long extensor of the toes, or anterior extensor
+of the phalanges, of which it shares the insertions. It
+extends the phalanges into which it is inserted. It also
+flexes the foot.</p>
+
+<p class="pagenum"><a name="Page_227" id="Page_227">[227]</a></p>
+
+<h5>Muscles of the Posterior Region</h5>
+
+<p>It will not be unprofitable to recall to mind that, in man,
+the muscles of this region are arranged in two layers:
+a superficial layer consisting of the gastrocnemius and
+soleus, to which is added a muscle of little importance,
+the plantaris, and a deep layer formed by four muscles&mdash;the
+popliteus, flexor longus digitorum, tibialis posticus,
+and flexor longus pollicis.</p>
+
+<p>The gastrocnemius and soleus, independent in their upper
+portion, unite below in a common tendon; they thus
+form also a triceps muscle, which we designate under the
+name of the triceps of the leg, or triceps suralis, because
+it forms the elevation of the calf of the leg (from <i>sura</i>,
+calf).</p>
+
+<p><b>Gastrocnemius</b> (<a href="#Fig083">Fig. 83</a>, 9, 11; <a href="#Fig084">Fig. 84</a>, 13, 14; <a href="#Fig086">Fig. 86</a>,
+7, 9; <a href="#Fig088">Fig. 88</a>, 13).&mdash;The external and internal heads of
+the gastrocnemius, distinct from one another only in their
+upper portion, arise from the shaft of the femur, above
+the condyles, on the borders of the popliteal surface, to a
+relatively considerable extent in the great quadrupeds.</p>
+
+<p>At this level they are situated in the popliteal region&mdash;that
+is to say, in the space limited externally by the biceps,
+and internally by the semi-tendinosus. But as they descend
+to a rather low level on the leg in quadrupeds, and especially
+in carnivora, they do not, properly speaking, determine a
+projection of the calf of the leg. However, they pass from
+this region but to be soon continued by a tendon&mdash;the tendo-Achillis,
+which is inserted into the calcaneum.</p>
+
+<p>Now, the region of the tarsus is called by veterinarians <i>the
+ham</i>, the posterior surface of which is angular, because of
+the oblique direction of the leg with regard to the vertical
+direction of the metatarsus and the presence of the
+calcaneum; the prominence which this surface presents has
+received the name of <i>the point of the ham</i>, and the tendon
+which ends there that of <i>the cord of the ham</i>.</p>
+
+<p>But the tendo-Achillis does not alone form this cord.
+Indeed, as we will soon see, the tendon of the superficial
+flexor of the toes takes part in its formation.</p>
+
+<p><span class="pagenum"><a name="Page_228" id="Page_228">[228]</a></span>We may add, with regard to the tendo-Achillis, that it
+is more clearly perceived as an external feature, because the
+skin sinks in front of it, as it does in man, over the lateral
+parts of the region which it occupies.</p>
+
+<p>The gastrocnemius, when it contracts, extends the foot
+on the leg.</p>
+
+<p>It serves to maintain the tibio-tarsal angle in the standing
+position, and during walking, to determine the steadying
+of the hind-limbs, which then, after the fashion of a spring,
+project the body forward.</p>
+
+<p>By an analogous movement they take part in the posterior
+projection of the hind-limbs in the act of kicking;
+but they are not the only ones to act in this case, the
+muscles of the buttock and thigh also being brought into
+play.</p>
+
+<p><b>Soleus</b> (<a href="#Fig083">Fig. 83</a>, 10; <a href="#Fig086">Fig. 86</a>, 8).&mdash;This muscle, much less
+developed in quadrupeds than in man, does not exist in the
+dog.</p>
+
+<p>With regard to the soleus in the pig, Professor Lesbre says:
+&#8216;Meckel denied its existence; we, however, believe that it
+is united to the external head of the gastrocnemius, its
+origin being transferred to the femur.&#8217;<a name="FNanchor_32_32" id="FNanchor_32_32"></a><a
+href="#Footnote_32_32" class="fnanchor">[32]</a></p>
+
+<div class="footnote"><p><a name="Footnote_32_32" id="Footnote_32_32"></a><a href="#FNanchor_32_32"><span
+class="label">[32]</span></a> F. X. Lesbre, &#8216;Essai de Myologie compar&eacute;e de l&#8217;homme et des mammif&egrave;res
+domestiques en vue d&#8217;&eacute;tablir une nomenclature unique et rationelle,&#8217;
+Lyon, 1897, p. 169.</p></div>
+
+<p>But in animals in which it exists, this muscle, of but little
+importance, occupies the outer side of the leg. It arises
+above from the external tuberosity of the tibia, and terminates
+below in a tendon which is united with that of the
+gastrocnemius.</p>
+
+<p>The soleus has the same action as these latter.</p>
+
+<p><b>Plantaris.</b>&mdash;In quadrupeds this muscle is blended with
+the superficial flexor of the toes, which we will study
+afterwards.</p>
+
+<p><b>Popliteus</b> (<a href="#Fig087">Fig. 87</a>, 16; <a href="#Fig088">Fig. 88</a>, 14).&mdash;In man, this
+muscle, which occupies the posterior surface of the tibia,
+above the oblique line, is completely covered by the gastrocnemius.</p>
+
+<p>In quadrupeds, where it is more voluminous, it projects<span class="pagenum"><a name="Page_229" id="Page_229">[229]</a></span>
+internally beyond the gastrocnemius, so that it is seen
+in the internal and superior part of the region of the superficial
+layer of muscles, immediately behind the internal
+surface of the tibia, which, as we know, is subcutaneous.</p>
+
+<p>The popliteus arises from the external surface of the
+external condyle of the femur. Thence its fibres which
+diverge pass to be inserted into the superior part of the
+posterior surface and of the internal border of the tibia.
+It is in this latter region that it projects beyond the
+gastrocnemius, but we may add that there it is more or less
+covered by the semi-tendinosus.</p>
+
+<p>It flexes the leg, and rotates it forwards.</p>
+
+<p><b>Superficial Flexor of the Toes</b> (<a href="#Fig083">Fig. 83</a>, 13, 15; <a href="#Fig084">Fig.
+84</a>, 17; <a href="#Fig086">Fig. 86</a>, 11, 13, 13; <a href="#Fig087">Fig.
+87</a>, 17; <a href="#Fig088">Fig. 88</a>, 15, 18, 18).&mdash;In
+man, the homologue of this muscle is found in the sole
+of the foot. It is called <i>the short flexor of the toes</i>. It arises
+from the calcaneum, and passes to the four outer toes. In
+quadrupeds, it rises as high as the back of the knee, and is
+found blended with the plantaris.</p>
+
+<p>Further designated by the name of <i>the superficial flexor
+of the phalanges</i>, covered in part by the gastrocnemius, with
+which it is in relation for a great part of the course which
+it traverses, this muscle arises from the posterior surface
+of the femur, on the external branch of the inferior bifurcation
+of the linea aspera. In the horse, this origin takes
+place in a depression situated above the external condyle,
+in the supracondyloid fossa. Then it accompanies the
+gastrocnemius, and becomes tendinous where the tendo-Achillis
+commences. It then winds round the latter in
+placing itself on its inner side, then on its posterior surface,
+and reaches the calcaneum. It accordingly contributes,
+as we have already pointed out, to form the cord of the
+ham. After having become expanded, and having covered
+as with a sort of fibrous cap the bone of the heel, it descends
+behind the metatarsus, and presents there an arrangement
+analogous to that which we pointed out in connection
+with the superficial flexor of the digits&mdash;that is, it contributes
+to form the <i>tendon</i>. This prominence, in the
+form of a cord, we see behind the canon-bone in solipeds<span class="pagenum"><a name="Page_230" id="Page_230">[230]</a></span>
+and ruminants. It finally terminates in the same way as
+the muscle with which we have compared it (see <a href="#Page_197">p. 197</a>).</p>
+
+<p>In the horse, its fleshy body is but slightly developed,
+so that its tendon alone is specially visible in the superficial
+muscular layer, but in the dog and the cat it is
+large. Hence it results that its fleshy body appears
+on each side of the inferior half of the gastrocnemius,
+and produces an elevation which recalls that which the
+soleus produces on each side of the same muscles in the
+human species.</p>
+
+<p>The muscles which follow form, with the popliteus, which
+we have already studied, the deep layer of the posterior
+region of the leg.</p>
+
+<p><b>Flexor Longus Digitorum</b> (<a href="#Fig087">Fig. 87</a>, 19; <a href="#Fig088">Fig. 88</a>, 17).&mdash;This
+muscle, in man, is the only common flexor of the toes
+belonging to the muscles of the leg.</p>
+
+<p>In comparison with the preceding muscle, it is a deep
+flexor. Veterinarians have given it the name of <i>the oblique
+flexor of the phalanges</i>.</p>
+
+<p>Visible on the internal aspect of the superficial layer of the
+muscles of the leg, this muscle arises above from the posterior
+surface of the external tuberosity of the tibia, becomes
+tendinous, passes towards the metatarsus, and blends with
+the tendons of the posterior tibial and the long proper
+flexor of the great-toe. In the dog and the cat it is blended
+with this latter only.</p>
+
+<p><b>Tibialis Posticus</b> (<a href="#Fig085">Fig. 85</a>, 14; <a href="#Fig086">Fig. 86</a>, 12; <a href="#Fig087">Fig. 87</a>, 20;
+<a href="#Fig088">Fig. 88</a>, 16).&mdash;This muscle arises from the external tuberosity
+of the tibia, and from the head of the fibula. Thence
+it passes to the tarsus, and terminates in different fashion
+in carnivora and other quadrupeds.</p>
+
+<p>In the dog and the cat, it is inserted into the ligamentous
+apparatus of the tarsus, or into the base of the second
+metatarsal.</p>
+
+<p>In the other quadrupeds with which we are here occupied
+it is blended with the long proper flexor of the
+great-toe.</p>
+
+<p>It is accordingly in the carnivora that the mode of termination
+of the tibialis posticus most nearly resembles<span class="pagenum"><a name="Page_231" id="Page_231">[231]</a></span>
+that of this same muscle in the human species. From this
+independence there results a special action.</p>
+
+<p>It is an adductor and internal rotator of the foot.</p>
+
+<p><b>Flexor Longus Pollicis</b> (<a href="#Fig084">Fig. 84</a>, 18; <a href="#Fig085">Fig. 85</a>, 14;
+<a href="#Fig086">Fig. 86</a>, 12; <a href="#Fig087">Fig. 87</a>, 18; <a href="#Fig088">Fig. 88</a>, 16).&mdash;This muscle, as
+that in man, is the most external of the deep layer of the
+leg. It is on the external aspect of the latter we perceive
+it, between the peroneals and the gastrocnemius or tendo-Achillis.</p>
+
+<p>It arises from the fibula and tibia, and is thence directed
+towards the tarsus. It unites with the long common flexor
+of the toes to form with it <i>the deep flexor of the phalanges</i>,
+of which it is the principal fasciculus. We may add that in
+the dog and the cat the posterior tibial remains independent
+of this latter, but that in the pig, ox, and horse the posterior
+tibial is united to the preceding to form with them the deep
+flexor muscle.</p>
+
+<p>Thus constituted, the deep flexor goes towards the
+phalanges, where it terminates as the deep flexor of the
+digits of the fore-limbs (see <a href="#Page_197">p. 197</a>). In animals possessed
+of a canon it contributes to form the <i>tendon</i> (<a href="#Fig085">Fig. 85</a>, 16;
+<a href="#Fig086">Fig. 86</a>, 14, 14; <a href="#Fig088">Fig. 88</a>, 19, 19).</p>
+
+<h5>Muscles of the Foot</h5>
+
+<p>We must remember that on the dorsal surface of the foot
+in man we find but a single muscle&mdash;the dorsalis pedis.
+The remaining subcutaneous structures of this region
+consist of the tendons of the anterior muscles of the leg
+which occupy this dorsal aspect.</p>
+
+<p><b>Dorsalis Pedis</b> (<a href="#Fig084">Fig. 84</a>, 19).&mdash;Also called the extensor
+brevis digitorum, the dorsalis pedis muscle is found in all
+domestic quadrupeds; but its development is so much the
+less as the number of digits is more reduced.</p>
+
+<p>In the dog and the cat it arises from the calcaneum, and
+is inserted into the three internal toes (the first toe excepted)
+by uniting with the corresponding tendons of the common
+extensor.</p>
+
+<p>In the pig its disposition is analogous.</p>
+
+<p><span class="pagenum"><a name="Page_232" id="Page_232">[232]</a></span>As for the dorsalis pedis of the ox and the horse, it is
+extremely rudimentary, and occupies the superior part of
+the canon. It is a small, fleshy body, situated on the anterior
+surface of the metatarsus, which arises from the calcaneum,
+whence it passes to unite at its inferior extremity
+with the tendon of the extensor of the phalanges.</p>
+
+<p>As regards the muscles of the sole of the foot, we think it
+unnecessary to occupy ourselves at any length with them because
+of their slight importance with regard to external form.</p>
+
+<p>We will only recall that in the median portion of this
+plantar surface we find in man the short flexor of the toes,
+which in quadrupeds arises higher up, from the posterior
+surface of the femur; that it belongs to the muscles of the
+leg; and that it forms the superficial flexor of the toes,
+which we have already studied.</p>
+
+<p>We may further add that the suspensory ligament of the
+fetlock in ruminants and solipeds represents, as in the fore-limbs,
+the interosseous muscles.</p>
+
+<h4><a name="HeadMuscles" id="HeadMuscles"></a>MUSCLES OF THE HEAD</h4>
+
+<p>We will divide these muscles into two categories:
+masticatory and cutaneous.</p>
+
+<h5>Masticatory Muscles</h5>
+
+<p>The muscles of this group which specially interest us are
+the masseter and the temporal. As regards the pterygoids,
+since they are situated within the borders of the inferior
+maxillary bone, and consequently do not reach the surface,
+we shall not require to occupy ourselves with them here.</p>
+
+<p><b>Masseter</b> (<a href="#Fig089">Fig. 89</a>, 2; <a href="#Fig090">Fig. 90</a>, 1; <a href="#Fig091">Figs. 91</a>,
+<a href="#Fig092">92</a>).&mdash;For those
+who have studied the masseter of man, it is not difficult to
+recognise that of quadrupeds. Nevertheless, the particular
+aspect which it presents in different species gives to its
+study a certain interest.</p>
+
+<p>Arising from the zygomatic arch, and passing downwards
+and backwards, it is inserted into the external surface of
+the ramus of the mandible and into its angle.</p>
+
+<p><span class="pagenum"><a name="Page_233" id="Page_233">[233]</a></span>Its posterior border is in relation with the parotid gland
+(<a href="#Fig090">Fig. 90</a>, 14; <a href="#Fig091">Figs. 91</a>, <a href="#Fig092">92</a>), this gland being situated between
+the corresponding border of the lower jaw bone and
+the transverse process of the atlas. Such are the general
+characters; the following are the particular ones:</p>
+
+<p>In the carnivora it is thick and convex. In the horse it
+is flat, but more expanded; it forms the <i>flat of the cheek</i>.
+In the ox it is flat, as in the latter; but, while being less
+thick, it is more prolonged in the vertical direction.</p>
+
+<p>The form of the osseous parts which give it origin is,
+besides, in relation with these differences, and explains the
+peculiar characters which the masseter presents.</p>
+
+<div class="figmed"><a name="Fig089" id="Fig089"></a>
+<img src="images/illo256.png" alt="Fig. 89" width="350" height="284" />
+<p class="caption just">Fig. 89.&mdash;Myology of the Dog: Masticatory Muscles (a Deeper
+Dissection than that shown in <a href="#Fig090">Fig. 90</a>).</p>
+
+<p class="subcaption just">1, Zygomatic arch; 2, masseter; 3, temporal exposed by the suppression
+of the auricular and occipital muscles and the pinna of the ear; 4,
+auditory canal; 5, inferior maxillary bone; 6, digastric.</p></div>
+
+<p>Indeed, in the dog and the cat the zygomatic arch,
+strongly convex, springs up in a marked manner from the
+plane of the lateral aspects of the skull.</p>
+
+<p>In the horse the same arch, less prominent externally, is
+prolonged by a rectilinear crest on the superior maxillary
+bone, where it is continued in forming the zygomatic or
+maxillary spine.</p>
+
+<p>In the ox the same crest ascends a good way towards the
+inferior margin of the orbit in a curved direction with the<span class="pagenum"><a name="Page_234" id="Page_234">[234]</a></span>
+concavity inferior, to redescend afterwards on the external
+surface of the superior maxilla.</p>
+
+<p>The masseter is an elevator of the lower jaw. It acts, above
+all, as in the human species, in the process of mastication.</p>
+
+<p><b>Temporal Muscle</b> (<a href="#Fig089">Fig. 89</a>, 3).&mdash;The development of the
+temporal is in proportion to the energy of the movements
+of elevation which the lower jaw has to execute.</p>
+
+<p>It arises from the temporal fossa, and is inserted into the
+coronoid process of the inferior maxilla.</p>
+
+<p>Its development, enormous in the carnivora, is such that
+the muscle projects beyond its fossa. It is less voluminous
+in the horse, and still less so in the ox. In the latter, indeed,
+the temporal fossa, although deep, is of small extent (see
+<a href="#Fig062">Fig. 62</a>, p. 119); the frontal bone being large, it is found to
+be thrown back on the lateral walls of the cranium, below
+the osseous processes which support the horns and overhang
+the fossa in question, as well as the muscle which it contains.</p>
+
+<p>It is covered by the auricular muscles, and by the base
+of the pinna of the ear.</p>
+
+<p>Like the masseter, the temporal is an elevator of the
+lower jaw.</p>
+
+<h5>Cutaneous Muscles of the Head</h5>
+
+<p><b>Occipito-Frontalis.</b>&mdash;The epicranial aponeurosis is extremely
+thin. In the dog the occipital muscle occupies the
+superior part of the head; it overlies the temporal muscle.</p>
+
+<p>With regard to the frontal muscle, which is of great extent
+in the ox (<a href="#Fig091">Fig. 91</a>, F), it is represented in the horse and the
+carnivora by a small fleshy fasciculus only, the <i>fronto-palpebral
+muscle</i>, similar to the superciliary muscle. This,
+occupying the superior and internal part of the border of
+the orbit, ends by blending its fibres with those of the
+orbicular muscle of the eyelids at the region of the eyebrow.</p>
+
+<p><b>Orbicularis Palpebrarum</b> (<a href="#Fig090">Fig. 90</a>, 2; <a href="#Fig091">Figs. 91</a>, <a href="#Fig092">92</a>).&mdash;This
+annular muscle surrounds the palpebral orifice, and takes
+its origin on the internal part of the orbital region. In the
+horse it arises, by a small tendon, from a tubercle which
+occupies the external surface of the os unguis, or lachrymal
+bone.</p>
+
+<p><span class="pagenum"><a name="Page_235" id="Page_235">[235]</a></span>This muscle determines the narrowing and closure of the
+palpebral orifice.</p>
+
+<p><b>Pyramidalis Nasi.</b>&mdash;The pyramidal muscle is not found
+in the domestic animals. It appears to be blended with
+the internal elevator of the upper lip and wing of the nose;
+this is easy of comprehension if we bear in mind the relative
+position of these two muscles in the human species.</p>
+
+<div class="figmed"><a name="Fig090" id="Fig090"></a>
+<img src="images/illo258.png" alt="Fig. 90" width="350" height="284" />
+<p class="caption just">Fig. 90.&mdash;Myology of the Dog: Muscles of the Head.</p>
+
+<p class="subcaption just">1, Masseter; 2, orbicularis palpebrarum; 3, zygomaticus major; 4, lachrymal
+(this muscle is sometimes described under the name of the small
+zygomatic); 5, levator labii superioris proprius; 6, levator labii superioris
+al&aelig;que nasi; 7, caninus; 9, buccinator; 11, zygomatico-auricularis;
+12, external temporo-auricularis; 14, parotid gland; 15, parotido-auricularis;
+16, inferior maxillary bone; 17, digastric.</p></div>
+
+<p><b>Corrugator Supercilii.</b>&mdash;This muscle is represented by
+the fronto-palpebral muscle noticed above, which is by some
+regarded as a vestige of the frontal.</p>
+
+<p><b>Zygomaticus Major</b> (<a href="#Fig090">Fig. 90</a>, 3; <a href="#Fig091">Figs. 91</a>, <a href="#Fig091">92</a>).&mdash;This is
+the <i>zygomatic-labial</i> of veterinarians. This muscle is of an
+elongated form, and has a ribbon-like aspect.</p>
+
+<p>In the dog and the cat it arises from the base of the pinna
+of the ear, from the portion of this base which bears the
+name of scutiform cartilage. (With regard to this cartilage,
+see <a href="#Page_242">p. 242</a>, <b>Zygomatico-auricularis</b>.) From
+this it is directed<span class="pagenum"><a name="Page_236" id="Page_236">[236]</a></span>
+downwards and forwards, to terminate, after having crossed
+the masseter, on the deep surface of the skin of the corresponding
+labial commissure.</p>
+
+<p>This mode of termination is the same in the ox and the
+horse; but where the muscle differs is at the level of its
+upper extremity. There it ascends less than in the carnivora.
+In the ox it arises from the zygomatic arch in the neighbourhood
+of the temporo-maxillary articulation; in the pig and
+the horse its origin is still lower, on the surface of the
+masseter, close to the maxillary spine.</p>
+
+<p>When it contracts, it draws upwards the labial
+commissure.</p>
+
+<p>Now, in man, we remember, it is the great zygomatic
+that, by an action of the same kind, determines the essential
+characters of the expression of laughing.</p>
+
+<p>There is, accordingly, a connection to be established
+between those displacements which are similar and the
+analogy of facial expression which necessarily results from
+them.<a name="FNanchor_33_33" id="FNanchor_33_33"></a><a href="#Footnote_33_33" class="fnanchor">[33]</a></p>
+
+<div class="footnote"><p><a name="Footnote_33_33" id="Footnote_33_33"></a><a
+href="#FNanchor_33_33"><span class="label">[33]</span></a> &Eacute;douard Cuyer, &#8216;The Mimic,&#8217; Paris, 1802.</p></div>
+
+<p><b>Zygomaticus Minor</b> (<a href="#Fig090">Fig. 90</a>, 4; <a href="#Fig091">Figs. 91</a>, <a href="#Fig092">92</a>).&mdash;The
+existence of this muscle has not been clearly demonstrated.
+Nevertheless, Straus-Durckheim noted its presence in the
+horse, and described it as &#8216;a muscle arising by two heads,
+of which one, the superior, arises from the malar bone below
+the orbit, and passes downwards and forwards over the fibro-adipose
+layer which supports the moustache. The second,
+the inferior, arises from the alveolar border in front of the
+second molar tooth, and passes forward to be inserted into
+the same fibro-adipose layer.&#8217;<a name="FNanchor_34_34"
+id="FNanchor_34_34"></a><a href="#Footnote_34_34" class="fnanchor">[34]</a></p>
+
+<div class="footnote"><p><a name="Footnote_34_34" id="Footnote_34_34"></a><a
+href="#FNanchor_34_34"><span class="label">[34]</span></a> H. Straus-Durckheim, &#8216;Anatomie descriptive et comparative du
+chat,&#8217; Paris, 1845, t. ii., p. 210.</p></div>
+
+<p>In connection with other quadrupeds, it is described by
+certain authors as a very thin muscle, arising below the
+cavity of the orbit, where it is blended with the fibres of the
+internal elevator of the upper lip and the ala of the nose;
+thence it proceeds to terminate below by uniting with the
+subcutaneous muscle. But this muscle is regarded by other<span class="pagenum"><a name="Page_237" id="Page_237">[237]</a></span>
+authors as the lachrymal muscle, which does not exist in
+this state in man, but of which the development is particularly
+remarkable, as to extent, in the ox, in which it
+descends as far as the buccinator.</p>
+
+<p>According to other authors, some of the fibres of this
+muscle constitute the small zygomatic.</p>
+
+<div class="figmed"><a name="Fig091" id="Fig091"></a>
+<img src="images/illo260.png" alt="Fig. 91" width="350" height="330" />
+<p class="caption just">Fig. 91.&mdash;Myology of the Ox: Muscles of the Head.</p>
+
+<p class="subcaption just">1, Masseter; 2, orbicularis palpebrarum; F, frontalis; 3, zygomaticus
+major; 4, lachrymal (this muscle is sometimes described under the
+name of small zygomatic); 5, levator labii superioris proprius; 6,
+levator labii superioris al&aelig;que nasi; 7, levator anguli oris or caninus; 8,
+orbicularis oris; 9, buccinator; 10, maxillo-labial; 11, zygomatico-auricularis;
+12, external temporo-auricularis; 14, parotid gland; 15, parotido-auricularis;
+16, inferior maxillary bone.</p></div>
+
+<p><b>Levator Labii Superioris Proprius</b> (<a href="#Fig090">Fig. 90</a>, 5; <a href="#Fig091">Figs. 91</a>,
+<a href="#Fig092">92</a>).&mdash;Also named by veterinarians the <i>supramaxillo-labial</i>,
+or again, the <i>proper elevator of the upper lip</i>, this muscle
+arises from the external surface of the superior maxillary
+bone, passes under the superficial elevator, which we shall
+study in the succeeding paragraph, and goes to be inserted
+into the thickness of the lip, to which its name indicates
+that it belongs.</p>
+
+<p><span class="pagenum"><a name="Page_238" id="Page_238">[238]</a></span>The peculiarities of this muscle in different animals are
+the following:</p>
+
+<p>In the dog and the cat it arises behind the infra-orbital
+foramen.</p>
+
+<p>In the pig it arises from a depression below the orbital
+cavity, and its fleshy body is terminated in front by a strong
+tendon in the upper part of the snout, in which it divides
+into fasciculi.</p>
+
+<p>In the ox it arises from the maxillary spine.</p>
+
+<p>In the horse it arises below the orbital cavity; then, after
+having crossed the superficial elevator, it ends in a tendinous
+expansion, situated in the median line between the nasal
+foss&aelig;. This expansion divides into fasciculi, which end in
+the thickness of the upper lip.</p>
+
+<p>By the contraction of this muscle, the lip is raised, on one
+side only, if a single muscle contracts, or in its whole extent,
+if the two muscles act simultaneously.</p>
+
+<p><b>Internal Elevator (or Superficial) of the Upper Lip
+and the Wing of the Nose</b> (<i>levator labii superioris al&aelig;que
+nasi</i>) (<a href="#Fig090">Fig. 90</a>, 6; <a href="#Fig091">Figs. 91</a>,
+<a href="#Fig092">92</a>).&mdash;This is the muscle veterinarians
+designate <i>the supranaso-labial</i>.</p>
+
+<p>Arising from the frontal and nasal bones, it thence passes
+towards the upper lip, where it is inserted as well as into
+the wing of the nose.</p>
+
+<p>In the ox it is united above with the frontal muscle, and
+below is divided into two fasciculi, between which pass the
+elevator described above and the canine muscle.</p>
+
+<p>In the horse it is also divided into two fasciculi; but
+the arrangement is the opposite as regards, their relations
+with neighbouring muscles, in this animal and in the
+preceding.</p>
+
+<p>In the ox the external fasciculus is covered by the external
+elevator and the canine, which pass under the internal
+fasciculus; in the horse the deep elevator passes under the
+two fasciculi, and the canine passes under the external
+bundle, and afterwards covers the internal.</p>
+
+<p>In the pig, the internal elevator is wanting.</p>
+
+<p>As its name indicates, it raises the upper lip and the wing
+of the nose.</p>
+
+<p><span class="pagenum"><a name="Page_239" id="Page_239">[239]</a></span><b>Transversus Nasi.</b>&mdash;In the horse this muscle, which is
+very thin, is situated on the dorsum of the nose, and proceeds
+to be inserted into the cartilaginous skeleton of the
+nostrils. In the pig, it occupies an analogous situation.
+It does not exist in the ox or in carnivora. The transversus
+nasi is a dilator of the nostrils.</p>
+
+<div class="figmed"><a name="Fig092" id="Fig092"></a>
+<img src="images/illo262.png" alt="Fig. 92" width="350" height="355" />
+<p class="caption just">Fig. 92.&mdash;Myology of the Horse: Muscles of the Head.</p>
+
+<p class="subcaption just">1, Masseter; 2, orbicularis palpebrarum; 3, zygomaticus major;
+4, lachrymal (this muscle is sometimes described under the name of the
+small zygomatic); 5, external elevator (or deep) of the upper lip and ala
+of the nose; 6, internal elevator (or superficial) of the upper lip and of
+the ala of the nose; 7, levator anguli oris or caninus; 8, orbicularis oris;
+9, buccinator; 10, maxillo-labialis; 11, zygomatico-auricularis; 12, temporo-auricularis
+externus; 13, cervico-auricularis; 14, parotid gland; 15, parotido-auricularis;
+16, inferior maxillary bone.</p></div>
+
+<p><b>Caninus</b> (<a href="#Fig090">Fig. 90</a>; <a href="#Fig007">Figs. 7</a>,
+<a href="#Fig091">91</a>, <a href="#Fig092">92</a>).&mdash;This is the muscle
+called by veterinarians <i>the great supramaxillo-nasal</i>.</p>
+
+<p>In the dog and the cat it is situated below the inferior
+border of the external elevator of the upper lip, of which it
+follows the direction. It arises, as does this latter, from the
+external surface of the maxilla, and goes also to terminate
+in the upper lip by blending with the internal elevator<span class="pagenum"><a name="Page_240" id="Page_240">[240]</a></span>
+of this lip and of the al&aelig; of the nose. It raises the
+upper lip.</p>
+
+<p>In the ox, it arises from the maxillary spine, and then
+divides into three parts; the superior passes under the
+internal portion of the internal elevator of the upper lip and
+the al&aelig; of the nose, and goes into the nostril; whilst the two
+others, situated lower down, terminate in the upper lip.</p>
+
+<p>In the pig, it is formed of two superimposed fasciculi,
+which arise from the spine of the maxilla and the impressions
+in front of it. These two fasciculi terminate in the snout,
+which they move laterally.</p>
+
+<p>In the horse, it is situated at a certain distance from the
+external elevator; in the preceding animals it is in contact
+with the latter. Arising behind from the external surface
+of the maxilla, in front of the maxillary spine, it is directed
+towards the anterior part of the face, passes under the
+external portion of the internal elevator (it is the opposite
+of this in the ox), and proceeds, on expanding, to terminate
+in the skin of the nostril. By its contraction it
+dilates the latter.</p>
+
+<p><b>Orbicularis Oris</b> (<a href="#Fig091">Fig. 91</a>, 8; <a href="#Fig092">Fig. 92</a>).&mdash;This muscle, very
+fleshy in the solipeds and the ruminants, is arranged as a
+ring round the buccal orifice, in the thickness of the lips,
+where it is blended with the other muscles of this region.</p>
+
+<p>Having for its function the narrowing of the orifice it
+surrounds, it acts during suction and in the prehension of
+food.</p>
+
+<p><b>Triangularis Oris.</b>&mdash;This muscle does not exist in
+domestic quadrupeds.</p>
+
+<p><b>Quadratus Menti.</b>&mdash;In the pig and the carnivora, it
+arises from the anterior part of the body of the inferior
+maxillary bone, and passes at the other end to terminate
+in the corresponding portion of the lower lip, which it
+depresses by its contraction.</p>
+
+<p>In the ox and the horse this muscle does not exist; it
+is replaced for the depression of the lower lip, which it
+affects in other animals, by supplemental fibres of the
+buccinator.</p>
+
+<p><b>The Prominence of the Chin.</b>&mdash;Below the lower lip in<span class="pagenum"><a name="Page_241" id="Page_241">[241]</a></span>
+the horse is situated the so-called <i>prominence of the chin</i>,
+limited posteriorly by the <i>beard</i>, a depressed region which
+gives point to the curb of the bridle.</p>
+
+<p>The prominence, which also exists in the ox, is a fibro-muscular
+pad which blends with the orbicular muscle of the
+lips, and receives on its superior aspect the insertion of the
+two muscles (<i>levator menti</i>) by which it is suspended. These
+arise, above, on each side of the symphysis of the inferior
+maxillary bone. They raise the lower lip with force, and
+they are the agents which, as we can sometimes observe in
+the horse, make it click against the upper lip, suddenly
+projecting it upwards. This action sometimes becomes a
+habit, and its continuance constitutes a vice.</p>
+
+<p>A corresponding structure is found in the pig and in the
+carnivora, but in them it does not produce an external
+prominence such as we have described.</p>
+
+<p><b>Buccinator</b> (<a href="#Fig090">Fig. 90</a>, 9; <a href="#Fig091">Figs. 91</a>, <a href="#Fig092">92</a>).&mdash;Further designated
+by the name of <i>alveolo-labial</i>, this muscle is situated on
+the lateral portions of the face, in the thickness of the
+cheeks. It consists of two layers, one superficial and the
+other deep.</p>
+
+<p>The deep portion arises from the portion of the alveolar
+border of the superior maxillary bone which corresponds
+to the molar teeth, and from the anterior border of the
+ramus of the mandible. Thence it is directed forwards,
+passes under the superficial layer, and blends with the
+fibres of the orbicular muscle of the lips. To this part of
+the buccinator some authors give the name of molar muscle.</p>
+
+<p>The superficial portion is formed by fibres which pass
+from the alveolar border of the superior maxillary bone to
+the corresponding border of the opposite bone. It is very
+highly developed in the herbivora.</p>
+
+<p>This muscle acts especially during mastication; it serves
+to press back again under the molar teeth the portions
+of food which fall outside the dental arch.</p>
+
+<p>In the pig, the ox, and the horse, a muscle which is considered
+as supplemental to the buccinator is placed along
+the inferior border of the latter.</p>
+
+<p>This muscle, which we describe separately under the names<span class="pagenum"><a name="Page_242" id="Page_242">[242]</a></span>
+of <i>maxillo-labialis</i> (<a href="#Fig091">Fig. 91</a>, 10; <a href="#Fig092">Fig. 92</a>) and <i>depressor of the
+lower lip</i>, is clearly distinct from the buccinator, especially
+in the horse. It arises, behind, with the deep layer of the
+muscle to which it is annexed, from the anterior border of
+the ramus of the lower jaw; in front it terminates in the
+thickness of the lower lip.</p>
+
+<p>In the ox, it is more intimately united with the buccinator.</p>
+
+<p>It depresses the lip to which it is attached, and displaces
+it laterally when it acts on one side only.</p>
+
+<p>In the human species, the pinna of the ear being generally
+immobile, the muscles which belong to it are, very naturally,
+considerably atrophied. Accordingly, the auricular muscles,
+anterior, superior, and posterior, are reduced to pale and
+thin fleshy lamell&aelig;, whose action is revealed in certain
+individuals, only in a way which may be said to be abnormal.</p>
+
+<p>It is not the same in quadrupeds. The pinna of the ear
+is extremely mobile, and its displacements have a real value
+from the point of view of physiognomical expression.
+It is therefore necessary to review the muscles which move
+this pinna without giving them, at the same time, more
+importance than they merit, since in themselves they do not
+determine the formation of surface reliefs, which are sufficiently
+apparent.</p>
+
+<p>Notwithstanding that for certain of these muscles it is
+possible to trace their analogy with those of the auricular
+region of man, it is very difficult, because of their complexity,
+to trace this analogy for all. This is why we shall not be
+able here, as we have done for the other muscles of the
+subcutaneous layer, to give at the head of each paragraph
+the name of a human muscle, and then to group in the same
+paragraph the muscles which correspond to it in different
+quadrupeds. Therefore the nomenclature and the divisions
+adopted for these latter must serve us as a base or starting-point.</p>
+
+<p>Because the pinna of the horse&#8217;s ear is so very mobile, we
+will first begin with a study of its auricular muscles.</p>
+
+<p><b>Zygomatico-auricularis</b> (<a href="#Fig092">Fig. 92</a>, 11).&mdash;This muscle, which
+is formed of two small bands of fleshy fibres, arises from the
+zygomatic arch in blending with the orbicular muscle of the<span class="pagenum"><a name="Page_243" id="Page_243">[243]</a></span>
+eyelids; thence it is directed towards the base of the pinna
+of the ear, and is inserted into this base, and also into the
+cartilaginous plate situated in front of and internal to this,
+and resting on the surface of the temporal muscle; this is
+the scutiform cartilage.</p>
+
+<p>The zygomatico-auricularis, which we look on as the
+homologue of the anterior auricular of man, draws the
+pinna of the ear forwards.</p>
+
+<p><b>Temporo-auricularis Externus</b> (<a href="#Fig092">Fig. 92</a>, 12).&mdash;This, which
+is thin and very broad, covers the temporal muscle.</p>
+
+<p>It arises from the whole extent of the parietal crest,
+blending in this plane, in its posterior half, with the muscle
+of the opposite side. Thence it is directed outwards towards
+the pinna of the ear, and is inserted into the
+internal border of the scutiform cartilage and on the inner
+side of the concha&mdash;that is to say, of the conchinian cartilage&mdash;which
+forms the principal part of the pinna. We are
+supposing, in the description of the muscles which move it,
+that this pinna has its opening directed outwards.</p>
+
+<p>The external temporo-auricular, which recalls, from
+its situation, the superior auricular of man, is an adductor
+of the ear; besides, it causes it to describe a movement of
+rotation from without inwards, so as to direct its opening
+forwards.</p>
+
+<p><b>Scuto-auricularis Externus.</b>&mdash;This muscle may be considered
+as supplementary to the external temporo-auricular;
+the concha fasciculus of this latter partly covers it.</p>
+
+<p>Extending from the scutiform cartilage to the inner side
+of the concha, it contributes to the movement of rotation
+by which the opening of the pinna of the ear is directed
+forwards.</p>
+
+<p><b>Cervico-auricular Muscles</b> (<a href="#Fig092">Fig. 92</a>, 13).&mdash;These
+muscles, three in number, are situated behind the pinna of
+the ear; they are called, from their mode of superposition,
+the superficial, middle, and deep.</p>
+
+<p>These arise, all three, from the superior cervical ligament,
+and pass from there towards the cartilage of the concha.
+They recall, as regards situation, the posterior auricular
+muscle of man.</p>
+
+<p><span class="pagenum"><a name="Page_244" id="Page_244">[244]</a></span><b>Superficial
+Cervico-auricular</b> (<i>Cervico-auricularis superioris</i>).&mdash;This
+muscle, inserted into the posterior surface of
+the concha, draws this cartilage backwards and downwards.</p>
+
+<p><b>Middle Cervico-auricular</b> (<i>Cervico-auricularis medius</i>).&mdash;Situated
+between the two other muscles of the same group,
+it proceeds, after having covered the superior extremity of
+the parotid gland, to be inserted into the external part of
+the base of the concha. It determines the rotation of this
+concha in such a way as to direct the opening of the ear
+backwards.</p>
+
+<p><b>Deep Cervico-auricular</b> (<i>Cervico-auricularis inferioris</i>).&mdash;Covered
+by the preceding muscle and the superior portion
+of the parotid, it is inserted into the base of the pinna
+of the ear, and has the same action as the middle cervico-auricular.</p>
+
+<p><b>Parotido-auricularis</b> (<a href="#Fig092">Fig. 92</a>, 15).&mdash;This is a long and
+thin fleshy band which arises from the external surface of
+the parotid gland, and tapering as it passes upwards
+towards the pinna of the ear, is inserted into the external
+surface of the base of the concha, below the inferior part of
+the angle of reunion of the two borders which limit its
+opening.</p>
+
+<p>It inclines the pinna outwards; it is, accordingly, an
+abductor of the pinna.</p>
+
+<p><b>Temporo-auricularis Internus.</b>&mdash;This muscle is covered
+by the external temporo-auricular and the superior cervico-auricular.
+It arises from the parietal crest, and is inserted
+into the internal surface of the concha. It is an adductor
+of the pinna of the ear.</p>
+
+<p>There are, finally, an internal scuto-auricular muscle and
+a tympano-auricular; but they do not present any interest
+for us; we can simply confine ourselves to making mention
+of them.</p>
+
+<p>In the ox, because of the situation of the temporal fossa
+and the fact that the external temporo-auricular muscle is
+applied, as in the horse, over the muscle which this fossa
+contains, this temporo-auricular muscle does not reach the
+middle line (<a href="#Fig091">Fig. 91</a>, 12).</p>
+
+<p>But in the cat and the dog this muscle covers all the upper<span class="pagenum"><a name="Page_245" id="Page_245">[245]</a></span>
+part of the head (<a href="#Fig090">Fig. 90</a>, 12). It is divided into two parts:
+the interscutellar and the fronto-scutellar.</p>
+
+<p>The interscutellar is a single muscle, thin and broad,
+covering the temporal muscle and a portion of the occipital,
+extending from the scutiform cartilage of the pinna of one
+side to the same cartilage of the pinna belonging to the side
+opposite. It approximates the two pinn&aelig; to one another
+by bringing them each into the position of adduction.</p>
+
+<p>The fronto-scutellar arises from the orbital process of the
+frontal bone, and from the orbital ligament, which at this
+level completes the interrupted osseous boundary of the
+orbital cavity. Thence it is directed, widening as it proceeds,
+towards the scutiform cartilage, and is there inserted by
+blending with the corresponding part of the great zygomatic.
+Its action is analogous to that of the preceding muscle; but,
+further, it directs the opening of the pinna forwards.</p>
+
+<p>These are the muscles which act, for example, when the dog,
+having his attention strongly attracted by any cause, pricks
+up his ears and turns the openings forward, in order the better
+to understand every sound which proceeds, or may possibly
+proceed, from that which he observes. From this, which
+may be extremely well seen in some individuals, results the
+appearance of vertical wrinkles of the skin in the interval
+between the pinn&aelig; of the ears, these being caused by the
+folding of the integument, whilst the pinn&aelig; approach one
+another. These movements, with which are associated
+fixation of look and a widening of the palpebral fissure,
+produce a peculiarly expressive look; this is why they
+merit our attention.</p>
+
+<p><b>Zygomatico-auricularis</b> (<a href="#Fig090">Fig. 90</a>, 11).&mdash;Arises from the
+internal surface of the great zygomatic, passes towards the
+pinna of the ear, and goes to be inserted into the external
+part of the base of the pinna, below its opening, to a prominence
+which corresponds to the antitragus of the human ear.
+It is to this antitragus, but proceeding from another
+direction, that the parotido-auricular muscle is inserted
+(<a href="#Fig090">Fig. 90</a>, 15).</p>
+
+<p>With regard to the cervico-auriculars, they are all three
+present. The superior, or superficial, situated behind the<span class="pagenum"><a name="Page_246" id="Page_246">[246]</a></span>
+interscutellar portion of the external temporo-auricular, has
+its origin on the median line of the neck; thence it passes
+towards the pinna of the ear, blending its fibres with those
+of the interscutellar muscle, and is inserted into the scutiform
+cartilage and the internal surface of the pinna.</p>
+
+<p>Such are the principal muscles of the ear in the carnivora;
+it would seem to us superfluous to dwell on the others of this
+region, so that we will here conclude the study of the
+muscles in general, and that of the myology of the head in
+particular.</p>
+
+<hr class="c25" />
+<p class="pagenum"><a name="Page_247" id="Page_247">[247]</a></p>
+<h2>CHAPTER III</h2>
+
+<h3>EPIDERMIC PRODUCTS OF THE TERMINAL
+EXTREMITIES OF THE FORE AND HIND LIMBS</h3>
+
+<p>We will first recall to mind that among the quadrupeds
+some are found of which the fingers and toes have their
+third phalanges terminated by claws&mdash;these are the unguiculates;
+and that in others the terminal extremity of
+each limb is completely encased in a horny envelope, the
+hoof&mdash;these are the ungulates.</p>
+
+<p>In the first group, the claws remind us to a certain extent
+of the arrangement of the nails in man; the inferior aspect
+of the paws is covered by an epidermic layer, thick and protective,
+which may be likened to the skin, correspondingly
+thick, which covers in the greater part of its extent the
+plantar surface of the foot in the human species.</p>
+
+<p>In the second group, the surface by which the third
+phalanx rests on the ground is correspondingly protected,
+but this time by a layer of horn which belongs to the hoof.</p>
+
+<p>After the preceding remarks, our study will be found to fall
+into a natural division, and it is in the order which we have
+just followed for the purpose of indicating its existence that
+we now proceed to study the nature and form of the different
+elements which complete or protect the digital extremities
+of the thoracic and abdominal limbs.</p>
+
+<p><b>Claws.</b>&mdash;These horny coverings of the third phalanges,
+which we have to consider only in the dog and cat, may be
+compared with the nails of man, with which, however, they
+present, as is well understood, characteristic differences.</p>
+
+<p>The claws are compressed laterally, curved on themselves,
+and are terminated in front by a sharp point in the felide,<span class="pagenum"><a name="Page_248" id="Page_248">[248]</a></span>
+but more blunted in the dog. Their superior border is
+convex and thick. We may say, therefore, that a claw is
+a sort of hollow tube, in the form of a cone flattened in the
+transverse direction, in which the third phalanx is set, and
+which is itself set in a groove formed by a kind of osseous
+hood which occupies the base of this third phalanx (see
+<a href="#Fig037">Fig. 37</a>, p. 57).</p>
+
+<div class="figmed"><a name="Fig093" id="Fig093"></a>
+<img src="images/illo272a.png" alt="Fig. 92" width="200" height="334" />
+<p class="caption just">Fig. 93.&mdash;Claw of the Dog:
+Inferior Surface.</p>
+
+<p class="subcaption just">1, Horny lamina of the claw;
+2, plantar nail; 3, tubercle of
+the corresponding digit.</p></div>
+
+<p>This definition is exact, as regards the general appearance;
+but, when more closely scrutinized, it is not
+sufficient. The tube in question is not formed of a single
+piece; each of the claws is formed by a lamina laterally
+folded, but of which the borders are not exactly
+joined together inferiorly; they leave between them a
+small interval, and this is filled by a layer of more friable
+horny substance, to which has been given the name of
+plantar nail. This arrangement, which is clearly defined
+in the dog (<a href="#Fig093">Fig. 93</a>), is comparable to that which we shall
+afterwards meet with in connection with the sole of the
+hoof of the horse (see <a href="#Fig100">Fig. 100</a>, p. 257). In the dog and
+the cat, the weight of the limb resting on the inferior
+surface of the phalanges, it was necessary that the region
+of the plantar surface of the foot corresponding to these
+latter should be protected; this is the function of certain
+fibro-adipose pads, which are situated there, and which
+are designated by the name of <i>plantar tubercles</i>.</p>
+
+<div class="figmed"><a name="Fig094" id="Fig094"></a>
+<img src="images/illo272b.png" alt="Fig. 94" width="250" height="418" />
+<p class="caption just">Fig. 94.&mdash;Left Hand of the Dog: Inferior
+Surface, Plantar Tubercles.</p>
+
+<p class="subcaption just">1, 1, 1, 1, 1, Tubercles of the fingers;
+2, plantar tubercle; 3, tubercle of the
+carpus.</p></div>
+
+<p><b>Plantar Tubercles</b> (<a href="#Fig094">Fig. 94</a>).&mdash;These tubercles, or dermic
+cushions, are divided, in each paw, into <i>tubercles of the digits</i>
+(or of the toes), a <i>plantar tubercle</i>, and, on the fore-limbs, a
+<i>tubercle of the carpus</i>.</p>
+
+<p>The tubercles of the fingers (or of the toes) are of the same
+number as the latter. That which belongs to the thumb
+is but little developed, but the others are more so. They
+are in relation with the plantar surfaces of the second and
+third phalanges, so that when the paw is in contact with
+the ground the articulation which, in each of the fingers or
+toes, joins these phalanges, rests on the corresponding pad.</p>
+
+<p>The plantar tubercle is larger than the preceding. It is
+of a more or less rounded form; sometimes it is triangular,
+and then comparable in outline to the ace of hearts, the point<span class="pagenum"><a name="Page_249" id="Page_249">[249]</a></span>
+of which is, in this case, turned towards the claws; its
+margin being sometimes strongly indented, it may also have
+a trilobate form. It is on it that rest the metacarpo-phalangeal
+or metatarso-phalangeal articulations, according
+to the limb studied. The tubercle of the carpus, situated
+at the level of the posterior surface of this latter, is less
+important than the preceding, the region which it occupies
+not reaching the ground during walking. But it is not to
+be neglected from the point of view of external form, because
+of the prominence which it produces.</p>
+
+<p>In the ungulates the terminal extremity of the limb is,
+as we have above pointed out, enclosed in a horny envelope
+which is no other than the hoof.</p>
+
+<p>We will first study the hoof of the horse&mdash;a hoof which<span class="pagenum"><a name="Page_250" id="Page_250">[250]</a></span>
+is single for each of the limbs, inasmuch as in this animal
+each of these has but a single digit.</p>
+
+<p><b>Hoofs of the Solipeds.</b>&mdash;We will first study the hoof as
+regarded in a general way&mdash;that is, without taking into
+account the limb to which it belongs. We will afterwards
+point out the differences presented when the hoofs of the
+fore and hind limbs are compared.</p>
+
+<p>In connection with the external forms of the horse, the
+study which we are now commencing is of great importance.
+But, before entering upon it, it appears to us necessary to
+rapidly examine what the hoof contains (<a href="#Fig095">Fig. 95</a>).</p>
+
+<div class="figmed"><a name="Fig095" id="Fig095"></a>
+<img src="images/illo273.png" alt="Fig. 95" width="350" height="270" />
+<p class="caption just">Fig. 95.&mdash;Vertical Antero-posterior Section of the Foot of a
+Horse.</p>
+
+<p class="subcaption just">1, Third phalanx; 2, fibro-cartilage; 3, podophyllous tissue; 4, inferior
+part of the wall; 5, section of the wall of the hoof; 6, cutigerous
+cavity; 7, tendon of the anterior extensor of the phalanges; 8, reinforcing
+band coming from the suspensory ligament of the fetlock;
+9, tendon of the superficial flexor of the phalanges; 10, tendon of the deep
+flexor of the phalanges.</p></div>
+
+<p>In the interior of this horny box we find the third phalanx,
+a small sesamoid bone placed opposite to the posterior border
+of the latter, a portion of the inferior extremity of the second
+phalanx, and the tendons, which terminate at this region.</p>
+
+<p>To the third phalanx are added two fibro-cartilaginous
+plates, flattened laterally, which prolong backwards the bone
+to which they are annexed. The inferior border of each of
+these fibro-cartilages is fixed by its anterior part to two
+osseous prominences situated at each of the angles which
+terminate the small phalanx behind; these prominences<span class="pagenum"><a name="Page_251" id="Page_251">[251]</a></span>
+are: <i>the basilar process</i> and <i>the retrorsal process</i> (<a href="#Fig096">Fig. 96</a>);
+by its posterior part, this border is continuous with a
+structure known as <i>the plantar cushion</i> (see <a href="#PlantarCushion">further on</a>).</p>
+
+<p>The posterior border is directed obliquely upwards and
+forwards. The superior border, which is convex or rectilinear,
+is thin, and is separated from the posterior border by
+an obtuse angle. Finally, the anterior border, which is
+directed obliquely downwards and backwards, is united to
+the ligamentous apparatus, which keeps the second and third
+phalanges in contact.</p>
+
+<p>These fibro-cartilages, at their upper extremities, project
+beyond the hoof, and therefore assist in the formation of
+the lateral regions of the foot,<a name="FNanchor_35_35" id="FNanchor_35_35"></a><a
+href="#Footnote_35_35" class="fnanchor">[35]</a> at the part which is
+called the <i>crown</i>. They project less above the hoof in the
+posterior limbs.</p>
+
+<div class="footnote"><p><a name="Footnote_35_35" id="Footnote_35_35"></a><a href="#FNanchor_35_35"><span
+class="label">[35]</span></a> Here, for the first time, apropos of the hoof, we use the word &#8216;foot.&#8217;
+As in osteology and in myology we have, for the sake of clearness of comparison,
+designated under this name the region limited above by the tarsus,
+it is necessary to point out here that we employ the same word for a more
+restricted region. This we did in conformity with the usage of veterinarians,
+who so designate the region of the hoof. It is necessary to explain this
+double employment of the word, and, further, to show the particular
+meaning ascribed to it.</p></div>
+
+<div class="figmed"><a name="Fig096" id="Fig096"></a>
+<img src="images/illo274.png" alt="Fig. 96" width="300" height="180" />
+<p class="caption just">Fig. 96.&mdash;Third Phalanx of the Horse: Left Anterior Limb,
+External Surface.</p>
+
+<p class="subcaption just">1, Pyramidal eminence; 2, surface, for articulation with the inferior
+extremity of the second phalanx; 3, basilar process; 4, retrorsal
+process.</p></div>
+
+<p>The posterior and inferior borders of these cartilages
+meet at an acute angle. The angle so formed, or cartilaginous
+bulb, constitutes the base of the region, which is
+commonly called the <i>heel</i>&mdash;a part of the foot which, as
+its name implies, is situated posteriorly, but which we
+must not confound, as we might be led to do, with the
+region occupied by the calcaneum. We know from our<span class="pagenum"><a name="Page_252" id="Page_252">[252]</a></span>
+previous studies of comparative osteology that this latter
+is situated much higher up.</p>
+
+<p><a name="PlantarCushion" id="PlantarCushion"></a>The <i>plantar cushion</i> is a sort of fibrous wedge which
+occupies the interval bounded by the fibro-cartilaginous
+plates which we have just been studying. Its inferior surface,
+the form of which we shall find to be reproduced by a
+portion of the corresponding surface of the hoof, is prolonged
+anteriorly into a point, while behind it is divided into
+two branches, which, diverging from one another, join the
+posterior angles of the fibro-cartilages. These two branches
+are separated by a median excavation.</p>
+
+<p>The different constituent elements which we have just
+been discussing give elasticity to the foot.</p>
+
+<p><a name="FleshFoot" id="FleshFoot"></a>To finish the examination of the parts contained in the
+hoof, we will add that among them is also found what is
+called the fleshy <i>envelope</i>, or <i>flesh</i> of the foot.</p>
+
+<p>We divide the latter into three regions: the podophyllous
+tissue, striated or laminated flesh which is spread out over
+the anterior surface of the third phalanx; the pad, or the
+hardened skin which corresponds to the upper border of the
+hoof, and forms a prominence above the podophyllous
+tissue; and the villous flesh, or velvety tissue which covers
+the plantar surface of the third phalanx and the plantar
+cushion. These three tissues form as a whole the keratogenic
+membrane&mdash;that is to say, that which produces horny
+tissue, and consequently regenerates the hoof.</p>
+
+<p>It is this latter that we now proceed to study.</p>
+
+<div class="figmed"><a name="Fig097" id="Fig097"></a>
+<img src="images/illo276.png" alt="Fig. 97" width="250" height="314" />
+<p class="caption just">Fig. 97.&mdash;Left Anterior Foot of the Horse: Anterior Aspect.</p>
+
+<p class="subcaption just">1, Outer side; 2, inner side.</p></div>
+
+<p>When we examine its anterior surface or the opposite one,
+the hoof of the horse has the shape of a truncated cone
+with the base below and the summit cut off obliquely
+downwards and backwards (<a href="#Fig097">Fig. 97</a>).</p>
+
+<div class="figmed"><a name="Fig098" id="Fig098"></a>
+<img src="images/illo277.png" alt="Fig. 98" width="350" height="316" />
+<p class="caption just">Fig. 98.&mdash;Left Anterior Foot of the Horse: External Aspect.</p>
+
+<p class="subcaption just">1, Fetlock; 2, spur or beard; 3, pastern; 4, outline determined by the
+external fibro-cartilage; 5, acute angle; 6, nipple; 7, quarter; 8, heel.</p></div>
+
+<p>Viewed on one of its lateral aspects, it may be compared
+to a truncated cylinder placed on the surface of the section
+(<a href="#Fig098">Fig. 98</a>). We particularly call attention to this latter comparison,
+for it singularly aids us in making a representation
+of the foot of the horse when viewed laterally.</p>
+
+<p>Notwithstanding that the hoof forms apparently a homogeneous
+whole, it consists of three parts, which may be
+separated from one another by maceration. The indication<span class="pagenum"><a name="Page_253" id="Page_253">[253]</a></span>
+of such disunion, artificially produced, may seem useless.
+It is not so, however, for this division of the hoof will
+permit us to carry out the study of the latter in a clearer, and
+consequently a more satisfactory, way. The three parts in
+question are the <i>wall</i>, or <i>crust</i>, the <i>sole</i>, and the <i>frog</i>.</p>
+
+<p>The <i>wall</i> is that portion of the hoof which we see when the
+foot rests on the ground. It is a plate of horn which,
+applied to the anterior and lateral surfaces of the foot,
+diminishes in height as it approaches the posterior part of the
+region. Posteriorly and at each side the wall is folded on
+itself, and is then directed forwards to terminate in a point,
+after having enclosed the <a href="#Frog">frog</a>, which we will soon study.</p>
+
+<p>Although the wall forms a continuous whole, it has been
+divided into regions to which special names are given. The
+anterior part, from the superior border to the inferior, is
+called the <i>pince</i> or <i>toe</i> for a width of 4 to 5 centimetres.
+External to the toe, and on each side of it, for a distance
+of 3 or 4 centimetres, is the <i>nipple</i>. Behind the <i>nipples</i> are
+the <i>quarters</i>. Still further back, where the wall folds on
+itself, forming the <i>buttress</i>, is found the region of the <i>heels</i>.<span
+class="pagenum"><a name="Page_254" id="Page_254">[254]</a></span>
+Finally, the portions of the wall which form its continuation
+in passing forward are called the <i>bars</i>.<a name="FNanchor_36_36"
+id="FNanchor_36_36"></a><a href="#Footnote_36_36" class="fnanchor">[36]</a> These are only
+visible on the inferior surface of the hoof (see <a href="#Fig100">Fig. 100</a>).</p>
+
+<div class="footnote"><p><a name="Footnote_36_36" id="Footnote_36_36"></a><a href="#FNanchor_36_36"><span
+class="label">[36]</span></a> It is to the angle of inflexion or heel that some authors give the name
+of buttress; it is the bars which other authors designate in this fashion.</p></div>
+
+<p>The wall, convex transversely, is, in its anterior part (viz.,
+the <i>toe</i>) inclined strongly downwards and forwards. This
+obliquity tends to become gradually effaced on the lateral
+parts to such a degree that at the quarters it becomes
+almost perpendicular to the surface of the ground.</p>
+
+<p>The internal quarter is less rounded than the external;
+in addition to this (<a href="#Fig097">Fig. 97</a>), it approaches more nearly to the
+vertical direction.</p>
+
+<div class="figmed"><a name="Fig099" id="Fig099"></a>
+<img src="images/illo278.png" alt="Fig. 99" width="250" height="215" />
+<p class="caption just">Fig. 99.&mdash;Vertical and Transverse Section of a Left Human Foot:
+Outline of the Divided Surface of the Posterior Segment
+of this Section (Diagrammatic Figure).</p>
+
+<p class="subcaption just">AA&#8242;, Vertical axis passing through the middle of the leg and the second
+toe; 1, outer side; 2, inner side.</p></div>
+
+<p>In our opinion, this latter difference clearly recalls certain
+characters of the general form of the human foot. In fact,
+the latter has its dorsal surface inclined downwards and
+outwards, whereas its internal border may be said rather to
+be vertical. A transverse section of the foot (<a href="#Fig099">Fig. 99</a>) justifies
+this comparison, which to us appears interesting, not only<span class="pagenum"><a name="Page_255" id="Page_255">[255]</a></span>
+as regards the resemblance which exists between these
+organs of support, but, further, because it constitutes a
+mnemonic which enables us, on condition that we remember
+the form of the human foot, to recall the above-described
+character of that of the horse.</p>
+
+<p>The greater convexity of the outer portion of the hoof is
+found equally on the human foot; the external border of
+this foot is more convex than the opposite one.</p>
+
+<p>The inferior border of the wall (<a href="#Fig100">Fig. 100</a>) is, in the case of
+unshod horses, always in wear when in contact with the
+ground. It is intimately united to the circumference of the
+sole (see <a href="#CircSole">further on</a>).</p>
+
+<div class="figmed"><a name="Fig100" id="Fig100"></a>
+<img src="images/illo279.png" alt="Fig. 100" width="300" height="303" />
+<p class="caption just">Fig. 100.&mdash;Inferior Surface of a Fore-hoof of the Horse: Left Side.</p>
+
+<p class="subcaption just">1, Internal border of the wall (toe); 2, wall; 3, quarter; 4, heel; 5,
+bar; 6, sole; 7, frog; 8, median cavity; 9, prominence of the frog;
+10, lateral cavity.</p></div>
+
+<p>The superior border is hollowed on its internal surface by
+a groove, the cutigerous cavity or basil, which lodges the
+cushion (see <a href="#Fig095">Fig. 95</a>). We have described this latter <a href="#FleshFoot">above</a>,
+in connection with the flesh of the foot.</p>
+
+<p>The substance of the wall presents a fibrous appearance
+which is pretty strongly pronounced. The constituent
+fibres from which this appearance results are directed
+from the superior border towards the inferior in parallel and
+regular lines.</p>
+
+<p><a name="CircSole" id="CircSole"></a>The <i>sole</i> is a horny plate which occupies the inferior surface
+of the hoof (<a href="#Fig100">Fig. 100</a>). It is situated between the inferior
+border of the wall and the bars; and, on account of the
+oblique direction of these latter, it presents a strongly-marked
+groove of a <span class="lettsymb">V</span>-form, with the opening directed backwards.
+In this depression is lodged the frog.</p>
+
+<p><span class="pagenum"><a name="Page_256" id="Page_256">[256]</a></span>The inferior surface is concave, and thus forms a sort of
+vault, more or less deep, according to the individual. The
+sole has a scaly, laminated aspect.</p>
+
+<p>We have seen (<a href="#Fig093">Fig. 93</a>, and <a href="#Page_249">p. 249</a>) that on the inferior surface
+of the claws of carnivora is found a small interval which
+is filled by a plate of a more friable horny substance, to which
+has been given the name of the plantar nail. It seems to us
+that there is an interesting relationship between the said
+plantar nail and the sole which we have just been studying.</p>
+
+<p>Indeed, these two horny structures appear to be homologous.
+Is not the lamina of the claw comparable to the
+wall of the hoof? And does not the interval which occurs
+at the inferior part of this latter, and is filled by the sole,
+recall that which, in extremely reduced form, is filled by
+the plantar portion of the claws?</p>
+
+<p><a name="Frog" id="Frog"></a>The <i>frog</i> (<a href="#Fig100">Fig. 100</a>) is a mass of horn, in form of a wedge,
+with its apex in front, which occupies the space limited
+laterally by the recurved portions of the wall (the bars) and
+the posterior border of the sole.</p>
+
+<p>It covers the plantar cushion previously described (<a href="#Page_252">p. 252</a>)
+and reproduces its form.</p>
+
+<p><span class="pagenum"><a name="Page_257" id="Page_257">[257]</a></span>Its inferior surface is hollowed out in the middle by an
+excavation, which is known as the <i>median lacuna</i>. This
+cavity separates the branches of the frog, which terminate
+posteriorly by two swellings which are known as <i>the
+prominences of the frog</i>, forming two rounded elevations
+situated above the claws. These same branches unite in
+front of the median lacuna to form the body of the frog.
+This latter, in its anterior part, gradually narrows, and
+terminates in a point which occupies the bottom of the
+hollow limited laterally by the bars of the wall and the
+posterior border of the sole.</p>
+
+<p>Between the lateral surfaces of the frog and the bars
+are found two angular cavities&mdash;<i>the lateral lacun&aelig;</i>, or the
+<i>commissures of the frog</i>.</p>
+
+<div class="figmed"><a name="Fig101" id="Fig101"></a>
+<img src="images/illo280a.png" alt="Fig. 101" width="300" height="213" />
+<p class="caption just">Fig. 101.&mdash;Third Phalanx of
+the Horse: Left Anterior
+Limb, Inferior View.</p>
+
+<p class="subcaption just">1, External border; 2, internal
+border; 3, semilunar crest; 4, 4,
+re-entrant processes.</p></div>
+
+<div class="figmed"><a name="Fig102" id="Fig102"></a>
+<img src="images/illo280b.png" alt="Fig. 102" width="300" height="224" />
+<p class="caption just">Fig. 102.&mdash;Third Phalanx of
+the Horse: Left Posterior
+Limb, Inferior View.</p>
+
+<p class="subcaption just">1, External border; 2, internal
+border; 3, semilunar crest; 4, 4,
+re-entrant processes.</p></div>
+
+<p>As an indispensable complement to the study which we
+have just made, it is necessary to add that the hoofs of the
+fore-limbs and those of the hind ones present differences
+of form which cannot be ignored&mdash;differences which we are
+already able to conjecture by looking at the respective third
+phalanges which terminate those limbs, and especially at
+their inferior surfaces (<a href="#Fig101">Figs. 101</a>, <a href="#Fig102">102</a>).</p>
+
+<p>The hoofs of the fore-limbs (see <a href="#Fig100">Fig. 100</a>), viewed on their
+plantar surface, are more rounded than those of the hind-limbs
+(<a href="#Fig103">Fig. 103</a>)&mdash;so that their external contour may be
+compared to a semicircle&mdash;whilst the hind-hoofs, which are<span class="pagenum"><a name="Page_258" id="Page_258">[258]</a></span>
+narrow and of more oval shape, rather recall by their form
+the aspect of an ogive.</p>
+
+<div class="figmed"><a name="Fig103" id="Fig103"></a>
+<img src="images/illo281.png" alt="Fig. 103"  width="300" height="306" />
+<p class="caption just">Fig. 103.&mdash;Inferior Surface of a Hind-hoof of a Horse: Left
+Side.</p>
+
+<p class="subcaption just">1, External border; 2, internal border.</p></div>
+
+<p>This seems to result from the fact that the fore-limbs support
+the more considerable part of the weight of the animal.
+The best proof which can be given of this overweighting is
+the eagerness with which very often, when a horse is stopped
+near the edge of a footpath, for example, he places his fore-feet
+on the latter. In thus raising his fore-quarters, he
+throws part of his weight backwards, and in this way
+relieves his fore-limbs.</p>
+
+<p>With regard to the difference of form which we have
+just pointed out, we have sometimes heard the following
+comparison made: the contour of the hoofs of the
+fore-limbs, viewed from below, recalls that of an apple;
+that of the hoofs of the hind-limbs recalls the outline of a
+pear.</p>
+
+<p>As a mnemonic this comparison is insufficient, for nothing
+connects either of the forms indicated with the region to
+which the hoofs belong.</p>
+
+<p>We much prefer one made for us this very year by one of
+the students of our course at the School of Fine Arts, after
+the lecture in which we had just pointed out the differences<span class="pagenum"><a name="Page_259" id="Page_259">[259]</a></span>
+in question. Giving the idea of a semicircle and an ogive,
+which we described above, he remarked to us that the idea
+would perhaps be more easily fixed in the memory if we
+associated with it the idea of the chronological order in
+which the Roman and ogival art succeeded. Indeed, as
+the Roman art preceded the ogival art, so the hoofs which
+have the semicircular form precede those which have the
+form of an ogive.</p>
+
+<p>This interpretation appeared to us ingenious; this is why
+we wished to give it here a place which seems to us to be
+merited.</p>
+
+<div class="figmed"><a name="Fig104" id="Fig104"></a>
+<img src="images/illo282.png" alt="Fig. 104" width="250" height="268" />
+<p class="caption just">Fig. 104.&mdash;Left Posterior Foot of a Horse: External Aspect.</p></div>
+
+<p>The wall of the hoof of a fore-limb, viewed on one of its
+lateral surfaces (see <a href="#Fig098">Fig. 98</a>), is more oblique than that of one
+of the hind-hoofs looked at in the same way (<a href="#Fig104">Fig. 104</a>).
+This difference, very marked especially at the region of the
+toe, is correlated with that of the direction of the pastern.
+In fact, in the anterior limbs this is a little more oblique
+than in the opposite ones.</p>
+
+<p>We have still to describe, in connection with the horse,
+some epidermic tissues, which are known as <i>chestnuts</i>.</p>
+
+<p>The chestnut is a small, horny plate which is found on<span class="pagenum"><a name="Page_260" id="Page_260">[260]</a></span>
+the internal surface of each of the limbs, at a level differing
+on the anterior from that of the posterior ones.</p>
+
+<p>On the anterior limbs the chestnut is situated on the
+internal surface of the forearm, towards the middle part,
+or the inferior third of this region. On the posterior limbs
+it is developed on the back of the superior extremity of the
+internal surface of the canon, towards the inferior part of
+the ham&mdash;that is, the tarsus.</p>
+
+<p>Inasmuch as some authors consider the chestnuts as being
+vestiges of the thumb and the great-toe, we propose giving
+a mnemonic which will enable us to remember their situation,
+or, rather, their difference of level.</p>
+
+<p>If we consider that the thumb, in the human species, is
+longer than the first toe, we may easily remember that the
+chestnut is placed higher in the anterior limbs than in the<span class="pagenum"><a name="Page_261" id="Page_261">[261]</a></span>
+posterior ones. Indeed, if we suppose a digit taking its
+origin at these points, it will be longer in front (the thumb)
+than behind (the first toe).</p>
+
+<div class="figmed"><a name="Fig105" id="Fig105"></a>
+<img src="images/illo283.png" alt="Fig. 105" width="275" height="434" />
+<p class="caption just">Fig. 105.&mdash;Foot of the Ox: Left Side, Antero-external View.</p>
+
+<p class="subcaption just">1, Internal hoof; 2, external hoof; 3, internal surface of this latter;
+4, internal spur.</p></div>
+
+<p><b>Hoofs of the Ox and the Pig.</b>&mdash;The ox has four hoofs
+on each foot&mdash;two which contain the third phalanges, and
+two others, rudimentary, situated at the posterior aspect
+of the limb, at the level of the inferior part of the canon;
+these latter bear the name of <i>spurs</i>. We will occupy ourselves
+especially with the former (<a href="#Fig105">Fig. 105</a>).</p>
+
+<p>Each of the hoofs presents three faces which, if we consider
+them in relation to the median axis of the limb to which they
+belong, are: external, internal, and inferior. The external
+surface resembles the wall of the hoof of the horse. The
+internal surface is slightly concave from before backwards,
+so that the external and internal hoofs of the same foot are
+not in contact with each other, except by the extremities
+of this surface, and that an interval separates them between
+these two points. The inferior surface, slightly depressed,
+ends behind in a swelling produced by the plantar cushion,
+which covers a thin lamina of horn.</p>
+
+<p>At the anterior part of the hoof these three surfaces unite
+in forming a well-marked angle which, on account of the concavity
+of the internal surface, is slightly curved towards the
+axis of the foot.</p>
+
+<p>The pig has also four hoofs&mdash;two for the great digits and
+two for the lateral digits. They recall those of the ox.</p>
+
+<hr class="c25" />
+<p class="pagenum"><a name="Page_262" id="Page_262">[262]</a></p>
+<h2>CHAPTER IV</h2>
+
+<h3>PROPORTIONS</h3>
+
+<p>Inasmuch as we have taken for granted, in connection with
+the present volume, that before entering on the study of the
+anatomy of quadrupeds the reader was prepared for it by a
+sufficient knowledge of human anatomy, it is quite natural
+that we should extend the same supposition to the study of
+proportions.</p>
+
+<p>For this reason, the definition of proportions, considered
+from a general point of view, their signification, their
+function and their utility, are questions which it would
+be superfluous to enter upon here. We will content
+ourselves by calling to mind that the common measure
+chosen by preference is the length of the head, and that,
+ordinarily, it is with it that we compare the dimensions of
+other parts.</p>
+
+<p>Among the animals whose structure we have examined,
+there is one of which the proportions deserve to be marked
+in preference to every other: this is the horse.</p>
+
+<p>Wherefore this preference? In the first place, it is because
+of the overwhelming position which this animal occupies in
+the artistic representation of quadrupeds; that it is more
+frequently associated with man; that, notwithstanding
+its division into different races, its general proportions may
+be referred to a special type.</p>
+
+<p>It is also because the indications relative to these proportions
+will suffice to show the way which the artist must
+follow in order to find for himself, at the time when the necessity
+for it arises, the proportions which characterize the
+other animals.</p>
+
+<p><span class="pagenum"><a name="Page_263" id="Page_263">[263]</a></span>Our intention is not, in connection with the subject which
+now occupies us, to enter into a deep discussion on the
+various opinions which have been set forth. We desire,
+above all, to give some indications which, from the practical
+point of view, can be utilized in the representation of the
+horse, and at the beginning to demonstrate the advantages
+of these indications. Now, there is a fact which we have had
+occasion to note; it is the following: almost invariably,
+when a person who is little accustomed to represent the
+horse, or not previously informed of certain proportions of
+lengths, begins to draw from nature, the error generally
+committed is that of making the head too small and the
+body too long. Is it a preconceived idea which is the cause
+that one regards them in this manner? Perhaps. At all
+events, certain artists who have made the representation
+of horses their special study have even had this habit.
+It is therefore necessary to be informed of the proportions;
+this is the object of the study which we are now
+undertaking.</p>
+
+<p>Bourgelat,<a name="FNanchor_37_37" id="FNanchor_37_37"></a><a href="#Footnote_37_37"
+class="fnanchor">[37]</a> in the eighteenth century, fixed for the
+first time and in complete fashion the proportions of the
+horse; it is he, consequently, who created the &aelig;sthetics
+of the horse. It is but justice to recall the fact. His
+system has a point of analogy with that which is employed to
+determine the human proportions. Indeed, Bourgelat chose
+the length of the head as a standard of measurement, and the
+subdivisions of the head for measures of less extent. &#8216;Since
+beauty,&#8217; said he,<a name="FNanchor_38_38" id="FNanchor_38_38"></a><a href="#Footnote_38_38"
+class="fnanchor">[38]</a> &#8216;resides in the congruity and proportion
+of the parts, it is absolutely necessary to observe the dimensions,
+individual and relative, and in order to acquire a
+knowledge of the proportions, to assume a kind of measure
+which can be indiscriminately common for all horses. The
+part which can serve as a standard of proportion for all the
+others is the head. Take a measurement between two
+parallel lines&mdash;one tangent to the nape of the neck or the<span class="pagenum"><a name="Page_264" id="Page_264">[264]</a></span>
+summit of the forelock, the other tangent to the extremity
+of the anterior lip&mdash;a line perpendicular to these two
+tangents will give you its geometrical length. Divide this
+length into three portions, and give to these three parts a
+special name, which may be applied indefinitely to all
+heads&mdash;as, for example, that of <i>prime</i>. Any head whatsoever
+will, accordingly, in its geometrical length, always have
+three <i>primes</i>; but all the parts which you will have to consider,
+whether in their length, in their height, or in their
+width, cannot constantly have either one prime, or a prime
+and a half, or three primes; subdivide, then, each <i>prime</i>
+into three equal parts, which you will name <i>seconds</i>, and as
+this subdivision will not suffice to give you a just measure of
+all the parts, subdivide anew each <i>second</i> into twenty-four
+<i>points</i>, so that a head divided into three <i>primes</i> will have, by
+the second division, nine <i>seconds</i>, and two hundred and
+sixteen <i>points</i> by the last.&#8217;</p>
+
+<div class="footnote"><p><a name="Footnote_37_37" id="Footnote_37_37"></a><a
+href="#FNanchor_37_37"><span class="label">[37]</span></a> Claude Bourgelat, founder of the veterinary schools in France. He
+was born at Lyons in 1712, and died at Paris in 1779.</p></div>
+
+<div class="footnote"><p><a name="Footnote_38_38" id="Footnote_38_38"></a><a
+href="#FNanchor_38_38"><span class="label">[38]</span></a> Bourgelat,
+&#8216;&Eacute;l&eacute;ments de l&#8217;art v&eacute;t&eacute;rinaire. Trait&eacute; de la conformation
+ext&eacute;rieure du cheval,&#8217; Paris, edition of 1785, p. 133.</p></div>
+
+<p>But where this system appears to us to have lost somewhat
+of its unity is when the author transforms it, in pointing out
+the following mode of procedure: &#8216;But the head itself may
+err by default of proportion. This part is not, indeed, considered
+as either too short or too long, too thin or too thick,
+but by comparison with the body of the animal. Now, the
+body, being required to have&mdash;whether in length, reckoning
+from the point of the arm to the prominence of the
+buttock, or in height, reckoning from the summit of the
+withers to the ground&mdash;two heads and a half; whenever
+the head, by its geometrical length, shall give, in length or
+in height, to the body measured more than two and a half
+times its own length, it will be too short; and if it gives
+less, it will be too long.</p>
+
+<p>&#8216;In the case in which one of these faults exists there would
+be no further question of establishing by its geometrical
+length the proportions of the other parts. Give up this
+common measure, and measure the height or the length of
+the body; divide the length or the height into five equal
+portions; take, then, two of these divisions, divide them
+into <i>primes</i>, <i>seconds</i>, and <i>points</i>, corresponding to the divisions
+and subdivisions which you would have made of the head,<span class="pagenum"><a name="Page_265" id="Page_265">[265]</a></span>
+and you will have a common measure, such as the head
+would have given you if it had been proportionate.&#8217;<a name="FNanchor_39_39"
+id="FNanchor_39_39"></a><a href="#Footnote_39_39" class="fnanchor">[39]</a></p>
+
+<div class="footnote"><p><a name="Footnote_39_39" id="Footnote_39_39"></a><a
+href="#FNanchor_39_39"><span class="label">[39]</span></a> Bourgelat, <i>loc. cit.</i>, p. 135.</p></div>
+
+<p>We understand, up to a certain point, that Bourgelat may
+have been able to give this advice which, generally speaking,
+is sufficiently practical, since, in certain cases, he was
+able to pronounce that such a head was too small or too
+large. But it is always mischievous, with regard to the
+effect produced on the reader, to propose to him, in the
+application of a rule, to suppress the foundation on which
+this rule is established. Besides, even if all the measurements
+compared with the two-fifths of the length of the body
+are proportionate with regard to one another, the animal,
+in spite of this, since the head must be taken into consideration,
+will, in a strict sense, be none the less disproportioned.</p>
+
+<div class="figlarge"><a name="Fig106" id="Fig106"></a>
+<img src="images/illo289.png" alt="Fig. 106" width="600" height="343" />
+<p class="caption center">Fig. 106.&mdash;The Proportions of the Horse (after Bourgelat).</p>
+
+<p class="fsize80 right"><i>To face p. 265.</i></p></div>
+
+<p>The proportions given by Bourgelat are as follows<a name="FNanchor_40_40"
+id="FNanchor_40_40"></a><a href="#Footnote_40_40" class="fnanchor">[40]</a>
+(<a href="#Fig106">Fig. 106</a>):</p>
+
+<div class="footnote"><p><a name="Footnote_40_40" id="Footnote_40_40"></a><a
+href="#FNanchor_40_40"><span class="label">[40]</span></a> <i>Ibid.</i>, p. 136, and onward.</p></div>
+
+<p>1. <b>Three geometrical lengths of the head</b> give:</p>
+
+<p><i>The full height</i> of the horse, reckoned from the forelock
+to the ground on which he rests, provided that the head be
+well placed.<a name="FNanchor_41_41" id="FNanchor_41_41"></a><a href="#Footnote_41_41" class="fnanchor">[41]</a></p>
+
+<div class="footnote"><p><a name="Footnote_41_41" id="Footnote_41_41"></a><a href="#FNanchor_41_41"><span
+class="label">[41]</span></a> By &#8216;the head being well placed,&#8217; Bourgelat means &#8216;vertically posed,&#8217;
+the outline of the forehead then coinciding with a vertical line, which at
+the other end touches the anterior portion of the nose.</p></div>
+
+<p><a name="P265Par2" id="P265Par2"></a>2. <b>Two heads and a half</b>
+(B)<a name="FNanchor_42_42" id="FNanchor_42_42"></a><a href="#Footnote_42_42"
+class="fnanchor">[42]</a> equals:</p>
+
+<p><i>The height of the body</i> from the summit of the withers to
+the ground.</p>
+
+<p><i>The length of the same body</i>, those of the forehand and of
+the hind-quarter taken as a whole from the point of the
+arm to the point of the buttock inclusive.</p>
+
+<div class="footnote"><p><a name="Footnote_42_42" id="Footnote_42_42"></a><a href="#FNanchor_42_42"><span
+class="label">[42]</span></a> The letters in parentheses relate to the corresponding measures
+marked by the same letters on the third diagram of <a href="#Fig106">Fig. 106</a>.</p></div>
+
+<p><a name="P265Par3" id="P265Par3"></a>3. <b>An entire head</b> (A) gives:</p>
+
+<p><i>The length of the forepart</i> from the summit of the withers
+to the termination of the neck.</p>
+
+<p><i>The height of the shoulders</i> from the summit of the elbow
+to the top of the withers.</p>
+
+<p><i>The thickness of the body</i> from the middle of the belly to
+the middle of the back.</p>
+
+<p><i>The width</i> from one side to the other.</p>
+
+<p><span class="pagenum"><a name="Page_266" id="Page_266">[266]</a></span><a name="P266Par4" id="P266Par4"></a>
+4. <b>A head measured from the top of the forelock to the
+commissure of the lips</b> (C). This measurement slightly
+curtailed, unless the mouth is very deeply cleft, equals:</p>
+
+<p><i>The length of the crupper</i>, taken from the superior point
+of the anterior angle of the ilium to the tuberosity of the
+ischium, forming the point of the buttock.</p>
+
+<p><i>The width of the crupper or of the haunches</i>, taken from
+the inferior points of the angles of the ilia.</p>
+
+<p><i>The height of the crupper</i>, viewed laterally, taken from the
+summit of the posterior angles of the ilia to the point of
+the patella, the leg being in a state of rest.</p>
+
+<p><i>The lateral measure of the posterior limb</i>, from the point
+of the patella, to the lateral and salient part of the ham,
+to the right of the articulation of the tibia with the
+trochlea.</p>
+
+<p><i>The perpendicular height of the articulation above named</i>
+above the ground.</p>
+
+<p><i>The distance from the point of the arm</i> to the angle
+formed by the junction of the head and neck.</p>
+
+<p><i>The distance from the summit of the withers</i> to the junction
+of the neck with the thorax.</p>
+
+<p>5. <b>Twice this last measure</b> (C)<a name="FNanchor_43_43"
+id="FNanchor_43_43"></a><a href="#Footnote_43_43" class="fnanchor">[43]</a> gives almost:</p>
+
+<p><i>The distance of the summit of the withers</i> to the tip of the
+patella.</p>
+
+<p><i>The distance of the point of the elbow</i> to the summit of the
+crupper or the posterior angles of the ilia.</p>
+
+<div class="footnote"><p><a name="Footnote_43_43" id="Footnote_43_43"></a><a href="#FNanchor_43_43"><span
+class="label">[43]</span></a> The proportions given in the two paragraphs 6 and 7 are, under
+another form, the same as those pointed out in paragraph 2, with this
+difference, that in this latter they are more clearly expressed.</p></div>
+
+<p>6. <b>Three times this measure, plus a half-width of the
+pastern, the equivalent of two heads and a half</b>, will
+give:</p>
+
+<p><i>The height of the body</i>, taken from the top of the withers
+to the ground.</p>
+
+<p><i>Its length</i>, taken from the point of the arm to the point
+of the buttock inclusive.</p>
+
+<p>7. <b>This same measure, plus the entire width of the
+pastern</b>, gives:</p>
+
+<p><i>The total length of the body</i>, taken accurately.</p>
+
+<p><span class="pagenum"><a name="Page_267" id="Page_267">[267]</a></span>8. <b>Two-thirds the length of the head</b> (D) will equal:</p>
+
+<p><i>The width of the chest</i>, from the tip of one arm to that of
+the other, from outside to outside.</p>
+
+<p><i>The horizontal measurement of the crupper</i> taken between
+two verticals, of which one forms a tangent to the buttock,
+and the other passes through the summit of the crupper
+and touches the tip of the patella.</p>
+
+<p><i>The third of the length of the hind-quarter and of the body</i>
+taken together, as far as the vertical from the withers,
+touching the elbow.</p>
+
+<p><i>The anterior length of the hind-limb</i>, taken from the tuberosity
+of the tibia to the fold of the ham.</p>
+
+<p><a name="P267Par9" id="P267Par9"></a>9. <b>One-half of the length of the head</b> (E) is the same as:</p>
+
+<p><i>The horizontal distance from the tip of the arm</i> to the
+vertical line from the summit of the withers and touching
+the elbow.</p>
+
+<p><i>The width of the neck</i>, viewed laterally, taken from its
+insertion in the trough of the jaw to the roots of the first
+hairs of the mane, on a line which forms with the superior
+contour two equal angles.</p>
+
+<p>10. <b>One-third of the entire length of the head</b> (F) gives:</p>
+
+<p><i>The height of its superior part</i> from the summit of the
+forelock to a line which passes through the most salient
+points of the orbits.</p>
+
+<p><i>The width of the head</i> below the lower eyelids.</p>
+
+<p><i>The lateral width of the forearm</i>, taken from its anterior
+origin to the point of the elbow.</p>
+
+<p>11. <b>Two-thirds of this length</b><a name="FNanchor_44_44" id="FNanchor_44_44"></a><a
+href="#Footnote_44_44" class="fnanchor">[44]</a> (G) gives:</p>
+
+<p><i>The distance of the point of the elbow</i> above the plane of
+the lower surface of the sternum.</p>
+
+<p><i>The depression of the back</i> in relation to the summit of
+the withers.</p>
+
+<p><i>The lateral width of the posterior limbs near the hams.</i></p>
+
+<p><i>The space or distance of the forearms from one ars</i><a name="FNanchor_45_45"
+id="FNanchor_45_45"></a><a href="#Footnote_45_45" class="fnanchor">[45]</a> to the
+opposite.</p>
+
+<div class="footnote"><p><a name="Footnote_44_44" id="Footnote_44_44"></a><a href="#FNanchor_44_44"><span
+class="label">[44]</span></a> That is to say, two-ninths of the whole length of the head.</p></div>
+
+<div class="footnote"><p><a name="Footnote_45_45" id="Footnote_45_45"></a><a href="#FNanchor_45_45"><span
+class="label">[45]</span></a> We call the region where the superior and internal part of the forearm
+is joined to the trunk the &#8216;ars.&#8217; The space between the ars of one side
+and the ars of the opposite side is called the &#8216;inter-ars.&#8217;</p></div>
+
+<p><span class="pagenum"><a name="Page_268" id="Page_268">[268]</a></span>12. <b>One-half
+of the third of the entire length of the head</b><a name="FNanchor_46_46"
+id="FNanchor_46_46"></a><a href="#Footnote_46_46" class="fnanchor">[46]</a>
+(H) equals:</p>
+
+<p><i>The thickness of the forearm</i>, viewed from the front, and
+taken horizontally from the ars to its external surface.</p>
+
+<p><i>The width of the crown of the fore-feet</i> whether from one
+side to the other, or from before backwards.</p>
+
+<p><i>The width of the crown of the hind-feet</i>, from one side to
+the other only.</p>
+
+<p><i>The width of the posterior fetlocks</i>, taken from the front to
+the origin of the spur.</p>
+
+<p><i>The width of the knee</i> seen from the front. Note: this
+measure is a little too large.</p>
+
+<p><i>The thickness of the ham.</i> Note: this measure is a little
+under the mark.</p>
+
+<div class="footnote"><p><a name="Footnote_46_46" id="Footnote_46_46"></a><a
+href="#FNanchor_46_46"><span class="label">[46]</span></a> That is to say, one-sixth of the total length of the head.</p></div>
+
+<p>13. <b>One-fourth of the third of the length of the head</b><a name="FNanchor_47_47"
+id="FNanchor_47_47"></a><a href="#Footnote_47_47" class="fnanchor">[47]</a>
+(I) gives:</p>
+
+<p><i>The thickness of the canon of the fore-limb</i>: that of the
+hind-quarter is a little thicker.</p>
+
+<div class="footnote"><p><a name="Footnote_47_47" id="Footnote_47_47"></a><a
+href="#FNanchor_47_47"><span class="label">[47]</span></a> That is, one-twelfth of the length of the head.</p></div>
+
+<p>14. <b>One-third of this same measure</b><a name="FNanchor_48_48"
+id="FNanchor_48_48"></a><a href="#Footnote_48_48" class="fnanchor">[48]</a> (K) equals:</p>
+
+<p><i>The thickness of the fore-limb close to the knee</i> in its
+narrowest part.</p>
+
+<p><i>The thickness of the posterior pasterns</i>, viewed laterally.</p>
+
+<div class="footnote"><p><a name="Footnote_48_48" id="Footnote_48_48"></a><a
+href="#FNanchor_48_48"><span class="label">[48]</span></a> That is, a ninth of the length of the head.</p></div>
+
+<p>15. <b>The height from the elbow to the fold of the knee</b>
+(L) is the same as:</p>
+
+<p><i>The height from this same fold to the earth.</i></p>
+
+<p><i>The height from the patella to the fold of the ham.</i></p>
+
+<p><i>The height from the fold of the ham to the crown.</i></p>
+
+<p>16. <b>The sixth part of this measure</b> (M) gives:</p>
+
+<p><i>The width of the canon of the fore-limb</i>, viewed laterally, in
+the middle of its length.</p>
+
+<p><i>The fetlock</i>, viewed from the front.</p>
+
+<p>17. <b>The third of this same measure</b> (N) is very nearly
+equal to:</p>
+
+<p><i>The width of the ham</i>, from the fold to the point.</p>
+
+<p>18. <b>A fourth of this measure</b> (O) gives:</p>
+
+<p><i>The width of the knee</i>, measured laterally.</p>
+
+<p><i>The length of the knee.</i></p>
+
+<p><span class="pagenum"><a name="Page_269" id="Page_269">[269]</a></span>19. <b>The interval between the eyes from one great angle
+to the other</b> (P) equals:</p>
+
+<p><i>The width of the hind-leg</i>, viewed laterally, from the
+cleft of the buttocks to the inferior part of the tuberosity
+of the tibia.</p>
+
+<p><a name="P269Par20" id="P269Par20"></a>20. <b>One-half of this interval between the eyes</b> (<sup>1</sup>&#8260;<sub>2</sub> P)
+gives:</p>
+
+<p><i>The width of the posterior canon-bone</i>, viewed laterally.</p>
+
+<p><i>The width of the fetlock of the fore-limb</i>, from its anterior
+summit to the root of the spur.</p>
+
+<p>Finally, the difference of the height of the crupper with
+respect to the summit of the withers.</p>
+
+<p>It is certain that the multiplicity of these proportions,
+and above all the exaggeration of details into which
+Bourgelat fell in indicating certain of the measures which
+constitute the bases of some of them, may repel the
+reader.</p>
+
+<p>For this cause we desire to add to the preceding, and
+also because the question which we are treating would be
+incomplete without it, the results obtained and published
+by other more modern authors, and in particular by Colonel
+Duhousset.<a name="FNanchor_49_49" id="FNanchor_49_49"></a><a href="#Footnote_49_49" class="fnanchor">[49]</a></p>
+
+<div class="footnote"><p><a name="Footnote_49_49" id="Footnote_49_49"></a><a
+href="#FNanchor_49_49"><span class="label">[49]</span></a> E. Duhousset, &#8216;Le Cheval,&#8217; Paris, 1881.</p></div>
+
+<p>This author, one of whose constant occupations is
+the measurement of the different regions of the horse,
+has the incontestable merit of having drawn attention
+to this question, and of having strained all his energies
+in the propagation of the knowledge which until then was
+little diffused. Among the proportions which he recommends,
+there are some which are the result of his own
+observations; whilst others, which he has verified and
+adopted, are the result of a judicious selection of those
+given by Bourgelat, which we have just reproduced in the
+preceding pages.</p>
+
+<div class="figmed"><a name="Fig107" id="Fig107"></a>
+<img src="images/illo295.png" alt="Fig. 107" width="500" height="377" />
+<p class="caption center">Fig. 107.&mdash;Proportions of the Horse (after Colonel
+Duhousset).</p></div>
+
+<p>We join thereto also certain indications furnished by
+MM. A. Goubeaux and G. Barrier,<a name="FNanchor_50_50" id="FNanchor_50_50"></a><a
+href="#Footnote_50_50" class="fnanchor">[50]</a> distinguishing these
+latter by the initials (G. and B.) of their authors (<a href="#Fig107">Fig. 107</a>).</p>
+
+<div class="footnote"><p><a name="Footnote_50_50" id="Footnote_50_50"></a><a
+href="#FNanchor_50_50"><span class="label">[50]</span></a> Armand Goubeaux and Gustave
+Barrier, &#8216;De l&#8217;ext&eacute;rieure du Cheval,&#8217;
+Paris, 1882.</p></div>
+
+<p><span class="pagenum"><a name="Page_270" id="Page_270">[270]</a></span><b>The length of the head almost exactly equals</b>:</p>
+
+<p>1. Depth from the back to the belly, N, O,<a name="FNanchor_51_51"
+id="FNanchor_51_51"></a><a href="#Footnote_51_51" class="fnanchor">[51]</a> the thickness
+of the body.<a name="FNanchor_52_52" id="FNanchor_52_52"></a><a href="#Footnote_52_52" class="fnanchor">[52]</a></p>
+
+<div class="footnote"><p><a name="Footnote_51_51" id="Footnote_51_51"></a><a
+href="#FNanchor_51_51"><span class="label">[51]</span></a> Look for the
+ points indicated by these letters on <a href="#Fig107">Fig. 107</a>, which is
+related to the proportions which are here discussed.</p></div>
+
+<div class="footnote"><p><a name="Footnote_52_52" id="Footnote_52_52"></a><a
+href="#FNanchor_52_52"><span class="label">[52]</span></a> The proportion
+previously indicated by Bourgelat (see <a href="#P265Par3">p. 265, paragraph
+3</a>).</p></div>
+
+<p>2. From the summit of the withers to the point of the
+arm, H, E.</p>
+
+<p>3. From the superior fold of the stifle to the point of the
+ham, J&#8242;, J.</p>
+
+<p>4. From the point of the ham to the ground, J, K.</p>
+
+<p>5. From the dorsal angle of the scapula to the point of
+the haunch, D, D.</p>
+
+<p>6. From the passage of the girth to the fetlock, M, I, or
+higher in large horses and racers; to the middle of the
+fetlock or lower for small ones and those of medium size.</p>
+
+<p>7. From the superior fold of the stifle to the summit of
+the crupper in those specimens whose coxo-femoral angle is<span class="pagenum"><a name="Page_271" id="Page_271">[271]</a></span>
+very open. This distance is always much less in others
+(G. and B.).<a name="FNanchor_53_53" id="FNanchor_53_53"></a><a href="#Footnote_53_53" class="fnanchor">[53]</a></p>
+
+<div class="footnote"><p><a name="Footnote_53_53" id="Footnote_53_53"></a><a
+href="#FNanchor_53_53"><span class="label">[53]</span></a> A proportion relative to the same region, and which at the outset
+might appear similar, is pointed out by Bourgelat (see <a href="#P266Par4">p. 266, paragraph 4</a>).
+But there exists a difference, for Bourgelat compared the length of the
+head, measured from the forelock to the commissure of the lips, and not
+that of the entire head, to the distance which separates the summit of
+the rump and the tip of the patella.</p></div>
+
+<p><b>Two and a half times the length of the head</b> gives:</p>
+
+<p>1. The height of the withers, H, above the ground.<a name="FNanchor_54_54"
+id="FNanchor_54_54"></a><a href="#Footnote_54_54" class="fnanchor">[54]</a></p>
+
+<div class="footnote"><p><a name="Footnote_54_54" id="Footnote_54_54"></a><a
+href="#FNanchor_54_54"><span class="label">[54]</span></a> This proportion is
+that given by Bourgelat (see <a href="#P265Par2">p. 265, paragraph 2</a>).</p></div>
+
+<p>2. The height of the summit of the crupper above the
+ground.<a name="FNanchor_55_55" id="FNanchor_55_55"></a><a href="#Footnote_55_55" class="fnanchor">[55]</a></p>
+
+<div class="footnote"><p><a name="Footnote_55_55" id="Footnote_55_55"></a><a
+href="#FNanchor_55_55"><span class="label">[55]</span></a> Consequently the withers and the crupper, being the same height, are
+situated on the same horizontal plane. Bourgelat, on the contrary,
+points out a difference of level in connection with these regions. According
+to him the summit of the crupper is situated below the horizontal plane
+passing the withers, and this distance equals half of the space which
+separates the great angle of one eye from that of the other (see <a href="#P269Par20">p. 269,
+paragraph 20</a>).</p></div>
+
+<p>3. Very often the length of the body, from the point of
+the arm to that of the buttock, although for a long time
+the type of Bourgelat had been set aside as a conventional
+model, short and massive.<a name="FNanchor_56_56" id="FNanchor_56_56"></a><a href="#Footnote_56_56" class="fnanchor">[56]</a></p>
+
+<div class="footnote"><p><a name="Footnote_56_56" id="Footnote_56_56"></a><a
+href="#FNanchor_56_56"><span class="label">[56]</span></a> See <a href="#P265Par2">p. 265, paragraph 2</a>.</p></div>
+
+<p>And M. Duhousset adds to this:</p>
+
+<p>&#8216;The drawing that we offer, which has two heads and
+a half in height and length, is that of a horse which
+we frequently meet with&#8217; (see <a href="#Fig107">Fig. 107</a>; see also <a href="#Page_279">p. 279</a>,
+where we again consider this question of the length of the
+body of the horse).</p>
+
+<p>&#8216;The crupper, from the point of the haunch to that of
+the buttock, D, F, is always less than that of the head.
+This difference varies from 5 to 10 centimetres. The
+width of the crupper, from one haunch to the other, often
+very slightly exceeds its length.&#8217; MM. Goubeaux and
+Barrier add that frequently it equals it.<a name="FNanchor_57_57" id="FNanchor_57_57"></a><a
+href="#Footnote_57_57" class="fnanchor">[57]</a></p>
+
+<div class="footnote"><p><a name="Footnote_57_57" id="Footnote_57_57"></a><a href="#FNanchor_57_57"><span
+class="label">[57]</span></a> If we refer to the proportions indicated by Bourgelat, we shall find
+that the proportions relative to the crupper are also indicated there
+(see <a href="#P266Par4">p. 266, paragraph 4</a>).</p></div>
+
+<p>&#8216;The crupper, such as we have just defined it, D, H, may
+also be found to a fair degree of exactness, as regards length,
+four times on the same horse.&#8217;<span class="pagenum"><a name="Page_272" id="Page_272">[272]</a></span></p>
+
+<p>1. From the point of the buttock to the inferior part of
+the stifle, F, P.</p>
+
+<p>2. The width of the neck, a little in front of the withers
+to a little above the point of the arm, S, X.<a name="FNanchor_58_58" id="FNanchor_58_58"></a><a href="#Footnote_58_58"
+class="fnanchor">[58]</a></p>
+
+<div class="footnote"><p><a name="Footnote_58_58" id="Footnote_58_58"></a><a href="#FNanchor_58_58"><span class="label">[58]</span></a>
+MM. Goubeaux and Barrier replace this by the following: &#8216;The width of
+neck at its inferior attachment from its insertion into the chest to the origin
+of the withers, S, X.&#8217; Bourgelat discovered the same proportion (see <a href="#P266Par4">p. 266</a>,
+last line of paragraph 4).</p></div>
+
+<p>3. From this latter point to below the lower jaw, X, Q,
+when the head is naturally placed parallel to the shoulders,
+E, H.<a name="FNanchor_59_59" id="FNanchor_59_59"></a><a href="#Footnote_59_59" class="fnanchor">[59]</a></p>
+
+<div class="footnote"><p><a name="Footnote_59_59" id="Footnote_59_59"></a><a href="#FNanchor_59_59"><span class="label">[59]</span></a>
+MM. Goubeaux and Barrier replace this by the following: &#8216;From
+the insertion of the neck into the chest to the lower border of the lower
+jaw, X, Q, when the head is parallel to the shoulder.&#8217;</p></div>
+
+<p>4. From the nape to the nostrils, <i>n, n&#8242;</i>.<a name="FNanchor_60_60" id="FNanchor_60_60"></a><a href="#Footnote_60_60"
+class="fnanchor">[60]</a></p>
+
+<div class="footnote"><p><a name="Footnote_60_60" id="Footnote_60_60"></a><a href="#FNanchor_60_60"><span class="label">[60]</span></a>
+MM. Goubeaux and Barrier add: &#8216;Or to the commissure of the lips.&#8217;
+It is thus, besides, that Bourgelat measured the head for comparison with
+the crupper (see <a href="#P266Par4">p. 266, paragraph 4</a>).</p></div>
+
+<p>The measure of <b>half of the head</b> also acts as a good
+guide for the construction of the horse, when we know that
+it frequently applies to many of the parts&mdash;to wit:</p>
+
+<p>1. From the forehead above the eyes, perpendicular to the
+line which is tangent to the lower jaw, P, Q.</p>
+
+<p>2. Outline of the neck at the level of the base of the head,
+Q, L.<a name="FNanchor_61_61" id="FNanchor_61_61"></a><a href="#Footnote_61_61" class="fnanchor">[61]</a></p>
+
+<div class="footnote"><p><a name="Footnote_61_61" id="Footnote_61_61"></a><a href="#FNanchor_61_61"><span class="label">[61]</span></a>
+Proportion indicated by Bourgelat (see <a href="#P267Par9">p. 267, paragraph 9</a>).</p></div>
+
+<p>3. From the crown of the fore-foot to below the knee,
+T, T&#8242;.</p>
+
+<p>4. In the legs, from the base of the fetlock to that of the
+ham, U, V.</p>
+
+<p>5. Finally, it is nearly of the length of the humerus from
+the point E to the radius.<a name="FNanchor_62_62" id="FNanchor_62_62"></a><a href="#Footnote_62_62" class="fnanchor">[62]</a></p>
+
+<div class="footnote"><p><a name="Footnote_62_62" id="Footnote_62_62"></a><a href="#FNanchor_62_62"><span class="label">[62]</span></a>
+MM. Goubeaux and Barrier replace these by the following:<br />
+1. &#8216;From the most prominent part of the lower jaw to the profile
+of the forehead above the eye, P, Q (thickness of the head).<br />
+2. &#8216;From the throat to the superior border of the neck behind the nape,
+Q, L (attachment of the head).<br />
+3. &#8216;From the inferior part of the knee to the crown, T, T&#8242;.<br />
+4. &#8216;From the base of the ham to the fetlock, U, V.<br />
+5. &#8216;Finally, from the point of the arm to the articulation of the elbow
+(approximate length of the arm).&#8217;</p></div>
+
+<p class="pagenum"><a name="Page_273" id="Page_273">[273]</a></p>
+
+<h4>PROPORTIONS OF THE HEAD OF THE HORSE<a name="FNanchor_63_63" id="FNanchor_63_63"></a><a href="#Footnote_63_63" class="fnanchor"
+style="font-size: .7em; font-weight: normal;">[63]</a></h4>
+
+<p>Although it is very difficult, says M. Duhousset, when we
+speak of measurements taken on the living animal, to
+formulate other than approximations, we believe we have
+determined with sufficient accuracy the following results,
+which are the outcome of our numerous observations. The
+head which we present is that of a horse which we have
+frequently come across as a mean term between the highly
+bred and the draught horse. Under this heading, it will not
+be devoid of interest to accompany with dimensions the
+two drawings to which are consigned the measurements
+in question.</p>
+
+<div class="footnote"><p><a name="Footnote_63_63" id="Footnote_63_63"></a><a href="#FNanchor_63_63"><span class="label">[63]</span></a>
+Extract from the work of MM. Goubeaux and Barrier on the exterior
+of the horse. As before, the initials G. and B. of these authors are
+added.</p></div>
+
+<div class="figmed"><a name="Fig108" id="Fig108"></a>
+<img src="images/illo299.png" alt="Fig. 108" width="350" height="429" />
+<p class="caption just">Fig. 108.&mdash;Proportions of the Head of the Horse, viewed in
+Profile (after Colonel Duhousset).</p></div>
+
+<p><b>Head viewed in Profile</b> (<a href="#Fig108">Fig. 108</a>).&mdash;Length, A, B,
+from the nape to the margin of the lips, 0&middot;60 metre.</p>
+
+<p>Thickness, C, D, from the angle of the lower jaw to the
+anterior surface (a half-head), 0&middot;30 metre. This line passes
+through the middle of the eye, taken perpendicularly, to
+the profile of the anterior surface. Many common horses
+present it, especially the heavier draught horses; in finely-bred
+subjects it is a little shorter (G. and B.).</p>
+
+<p>Depth, I, H, of the neck in its narrowest part (a half-head),
+0&middot;30 metre. It is frequently greater; this is noticeable
+in all instances where the superior parts of the neck
+are deficient in fineness. It is this which we see in
+draught horses, and in those which become too fleshy
+(G. and B.).</p>
+
+<p>Distance, O, R, of the internal commissure of the eye from
+the superior border of the commissure of the nostril (G. and
+B.) (a half-head), 0&middot;30 metre. It is more considerable on
+the common head, and on that which is too long.</p>
+
+<p>Distance, A, O, from the nape to the internal angle of the
+eye, 0&middot;22 metre. This distance is equivalent to the thickness
+of the head, P, Q, taken perpendicularly from the profile
+of the anterior surface, and passing at the level of the
+maxillary fissure and spine.</p>
+
+<p><span class="pagenum"><a name="Page_274" id="Page_274">[274]</a></span>It is, again, equal to Q, O, from the internal angle of the
+eye to the maxillary fissure; and to P, G, from the middle
+of the face to the commissure of the lips (G. and B.).</p>
+
+<p>The distance, P, E, from the middle of the face to the
+maxillary spine is about the sixth of the total length of the
+head&mdash;0&middot;10 metre.</p>
+
+<p>The line B, E, reckoned from the extremity of the lips to
+the maxillary spine, is equal:</p>
+
+<p>To E, F, from the maxillary spine to the external auditory
+meatus, to be seen only on the skull;</p>
+
+<p>To H, G, from the insertion of the neck in the trough to
+the commissure of the lips (G. and B.);</p>
+
+<p>To Q, R, from the maxillary fissure to the superior commissure
+of the nostril (G. and B.);</p>
+
+<p><span class="pagenum"><a name="Page_275" id="Page_275">[275]</a></span>To Q, B, from the fissure of the maxilla to the border of the
+lips (G. and B.);</p>
+
+<p>To O, D, from the internal angle of the eye to the angle of
+the lower jaw, provided that the line C, D be in proportion
+(G. and B.).</p>
+
+<div class="figmed"><a name="Fig109" id="Fig109"></a>
+<img src="images/illo300.png" alt="Fig. 109" width="350" height="382" />
+<p class="caption just">Fig. 109.&mdash;The Same Design as that of <a href="#Fig108">Fig. 108</a>, on which we have
+indicated, by Similar Lines, the Principal Corresponding
+Measurements.</p>
+
+<p class="subcaption just">Half the length of the head, and the dimensions which equal it; distance
+which separate the nape from the internal angle of the eye, and the
+dimensions which equal it; distance which separates the internal angle
+of the eye from the border of the lips, and the dimensions which equal it.<a
+name="FNanchor_64_64" id="FNanchor_64_64"></a><a href="#Footnote_64_64" class="fnanchor">[64]</a></p></div>
+
+<div class="footnote"><p><a name="Footnote_64_64" id="Footnote_64_64"></a><a href="#FNanchor_64_64"><span class="label">[64]</span></a>
+It is thus that in our teaching, but by means of lines of different
+colours, we present the proportions reproduced in <a href="#Fig108">Fig. 108</a>. Experience has
+demonstrated to us that this replacement of letters by conventional lines
+renders the proportions more easily appreciable, and that these lines,
+striking the eye more forcibly, then impress themselves better on the
+memory. <a href="#Fig111">Fig. 111</a> bears the same relation to <a href="#Fig110">Fig. 110</a>.</p></div>
+
+<p>Finally, very frequently to O, H, from the internal angle
+of the eye to the insertion of the throat into the maxillary
+trough (G. and B.).</p>
+
+<p><span class="pagenum"><a name="Page_276" id="Page_276">[276]</a></span>An equality still more frequent is that which exists between
+the distances:</p>
+
+<p>O, B, from the internal angle of the eye to the margin of
+the lips;</p>
+
+<p>A, H, from the nape to the insertion of the throat into the
+maxillary trough;</p>
+
+<p>And H, B, from this latter point to the margins of the lips.</p>
+
+<div class="figmed"><a name="Fig110" id="Fig110"></a>
+<img src="images/illo301.png" alt="Fig. 110" width="200" height="460" />
+<p class="caption just">Fig. 110.&mdash;Proportions of the Head of the Horse, seen from the
+Front (after Colonel Duhousset).</p></div>
+
+<p><b>The Head, Front View</b> (<a href="#Fig110">Fig. 110</a>).&mdash;If, to continue our
+examination, adds M. Duhousset, we regard the head from
+the front, we find its greatest width at A, B, the extreme
+points of the orbital arches.</p>
+
+<p>This width is 22 centimetres.</p>
+
+<p>It is again equal to:</p>
+
+<p>A, C, from one arch to the nape;</p>
+
+<p>A, D, from one arch to the middle of the face.</p>
+
+<p><span class="pagenum"><a name="Page_277" id="Page_277">[277]</a></span>D, E, from the middle of the face to the margin of the lips.</p>
+
+<p>From the auditory canal, G, to the maxillary spine, F,
+is the same distance as from this point to the margins of the
+lips, E, or, better, to the end of the teeth.</p>
+
+<div class="figmed"><a name="Fig111" id="Fig111"></a>
+<img src="images/illo302.png" alt="Fig. 111" width="200" height="521" />
+<p class="caption just">Fig. 111.&mdash;The Same Figure as <a href="#Fig110">Fig. 110</a>, on which we have marked
+by Similar Lines the Principal Measurements which correspond
+thereto.</p>
+
+<p class="subcaption just">Distance which separates one of the orbital arches from that of the
+opposite side, and the dimensions which equal it; distance which separates
+the auditory meatus from the maxillary spine, and the dimensions which
+equal it; distance which separates one maxillary spine from that of the
+opposite side, and the dimensions which equal it; distance which separates
+the lip of one side from that of the opposite, and the dimensions which
+equal it.<a name="FNanchor_65_65" id="FNanchor_65_65"></a><a href="#Footnote_65_65" class="fnanchor">[65]</a></p></div>
+
+<div class="footnote"><p><a name="Footnote_65_65" id="Footnote_65_65"></a><a href="#FNanchor_65_65"><span
+class="label">[65]</span></a> See the note relative to <a href="#Fig109">Fig. 109</a>.</p></div>
+
+<p>The line G, C, from the auditory meatus to the nape, is
+equal to the sixth of the head, 10 centimetres; the line A, G,
+from the orbital arch to the auditory meatus, is a little
+longer, and measures 12 centimetres.</p>
+
+<p><span class="pagenum"><a name="Page_278" id="Page_278">[278]</a></span>The distance F, I, comprised between the maxillary spines,
+is 18 centimetres.</p>
+
+<p>It is equal to:</p>
+
+<p>O, O, the distance between the internal angles of the eyes
+(G. and B.);</p>
+
+<p>F, R, the distance from the maxillary spine to the superior
+commissure of the corresponding nostril (G. and. B.);</p>
+
+<p>F, P, from the maxillary spine to the <i>salt-cellar</i>.<a name="FNanchor_66_66"
+id="FNanchor_66_66"></a><a href="#Footnote_66_66" class="fnanchor">[66]</a></p>
+
+<div class="footnote"><p><a name="Footnote_66_66" id="Footnote_66_66"></a><a href="#FNanchor_66_66"><span
+class="label">[66]</span></a> We designate under the name <i>salt-cellar</i> a depression situated external
+to the frontal region and above the eye.</p></div>
+
+<p>From the nape to the internal angle of the eye, C, O, is the
+same distance as from this latter point to the commissure
+of the lips, O, T; and from the maxillary spine to the upper
+lip F, S (G. and B.).</p>
+
+<p>The distance apart, T, T, of the two commissures of the
+lips gives, very nearly, the distance from the superior
+border of the orbital arch to the base of the ear or the
+auditory meatus. In the state of rest, the outer limit of the
+separation of the nostrils does not exceed the width of the
+knee;<a name="FNanchor_67_67" id="FNanchor_67_67"></a><a href="#Footnote_67_67"
+class="fnanchor">[67]</a> we frequently find the same distance intercepted
+above the nape by the tranquil ears. In the figure (<a href="#Fig110">Fig.
+110</a>) we have intentionally represented them directed in
+a different plane, in order to show that when the pinna is
+turned backward, it none the less preserves the contour
+of bracket form, more or less pronounced according to the
+breeding of the subject, and characterizing in repose the
+interior curves of the ear.</p>
+
+<div class="footnote"><p><a name="Footnote_67_67" id="Footnote_67_67"></a><a href="#FNanchor_67_67"><span class="label">[67]</span></a>
+We remind our readers that the name &#8216;knee&#8217; is given by veterinarians
+to the region occupied by the carpus.</p></div>
+
+<p>The extreme limit of the lips, M, N, but very slightly
+exceeds that of the nostrils; on many heads of harmonious
+proportions this distance is found to be the half of A, B.</p>
+
+<p>In order not to interrupt the course of the preceding exposition,
+we decided to withhold till afterwards some reflections
+which have been suggested to us by certain of the proportions
+which are there indicated. The proportions in question are
+important&mdash;we may even say that they are fundamental, for
+they have for object the relation which exists between the
+length of the head, the height of the body, and the length
+of the latter.</p>
+
+<p><span class="pagenum"><a name="Page_279" id="Page_279">[279]</a></span>We have already seen that, according to Bourgelat, the
+length of the head is contained two and a half times in the
+length of the body, from the point of the arm to the point
+of the buttock; and, also, two and a half times in the
+height measured from the apex of the withers to the
+ground (see <a href="#Page_265">p. 265</a>). We saw afterwards that M. Duhousset,
+having adopted these proportions, pointed out, further,
+that the same dimension was again found equally to exist
+from the summit of the crupper to the ground&mdash;a height
+which Bourgelat considered as being of less extent. There
+results, then, from the latter proportions, which we have just
+recalled, this interesting fact: that they simplify very much,
+from the point of view of design, the placing in position of
+the horse, on the condition always that this latter be always
+viewed directly on one of its lateral aspects.</p>
+
+<div class="figmed"><a name="Fig112" id="Fig112"></a>
+<img src="images/illo304.png" alt="Fig. 112" width="400" height="347" />
+<p class="caption just">Fig. 112.&mdash;Horse of which the Length contains more than Two
+and a Half Times that of the Head, and of which this
+Dimension (A, B) exceeds the Height.</p></div>
+
+<p>Indeed, in this case, if we except the neck and the head, the
+body, inasmuch as its height and its length are equal, may be
+inscribed in a square, of which one of the sides corresponds
+to the withers and to the summit of the crupper, two of the
+other sides to the point of the arm and to that of the buttock<span class="pagenum"><a name="Page_280" id="Page_280">[280]</a></span>
+the fourth being represented by the ground. This is simple,
+but this simplicity even has its inconveniences.</p>
+
+<p>It follows that this proportion, thus expressed, seems
+to exclude from every artistic representation certain categories
+of horses, which upon the whole might be regarded
+as beautiful, and the existence of which in any case it would
+be a pity not to indicate.</p>
+
+<div class="figmed"><a name="Fig113" id="Fig113"></a>
+<img src="images/illo305.png" alt="Fig. 113" width="400" height="320" />
+<p class="caption just">Fig. 113.&mdash;Horse of which the Length contains more than Two and
+a Half Times that of the Head, and of which this Dimension
+(A, B) exceeds the Height.</p></div>
+
+<p>Let us examine at the outset that which is relative to the
+length of the body, equal to two and a half times the length
+of the head. This proportion is sometimes met with, and
+therefore may be considered exact; but it is necessary to
+add that its existence is not discoverable in the majority
+of cases. That for some authors it constitutes a perfect
+model we will not gainsay, but it is our impression that,
+when it exists, the head appears a little large, or, more
+exactly, the body a little short.</p>
+
+<p>Without attaining exactly to three times the length of the
+head, as some authors (Saint-Bel, Vallon) have announced,
+the body of the horse, nevertheless, measured as is stated
+above, frequently contains it more than two and a half times.
+We give in support of this some outline reproductions, executed
+after photographs (<a href="#Fig112">Figs. 112</a>, <a href="#Fig113">113</a>, <a href="#Fig114">114</a>).</p>
+
+<p><span class="pagenum"><a name="Page_281" id="Page_281">[281]</a></span>There still remains the question regarding the equality
+of the height and of the length of the body of the horse.</p>
+
+<p>This equality, after the proportions previously indicated,
+would seem bound to appear in all the cases observed. Now,
+if we measure the examples reproduced in <a href="#Fig112">Figs. 112</a>, <a href="#Fig113">113</a>,
+and <a href="#Fig114">114</a>, we shall see that sometimes the two dimensions
+are unequal, the height being greater than the length, or
+inversely.</p>
+
+<div class="figmed"><a name="Fig114" id="Fig114"></a>
+<img src="images/illo306.png" alt="Fig. 114" width="400" height="364" />
+<p class="caption just">Fig. 114.&mdash;Horse of which the Length contains more than Two
+and a Half Times that of the Head, and of which this
+Dimension (A, B) is Inferior to the Height.</p></div>
+
+<p>It is the same, if we examine a certain number of specimens;
+we are able to determine that the proportion chosen
+in preference by authors is not exactly that which is oftenest
+met with. It will, very probably, be objected that it is so
+for the most beautiful types, and that the indifferent ones
+are generally the more numerous. The essential thing would
+be to know, above all, if the type of two heads and a half of
+length and of height is really the only beautiful one. However
+that may be, of the fifty African horses measured by
+M. Duhousset, only fourteen possessed the equality indicated;
+twenty-six were less long than high, and ten more
+long than high.<a name="FNanchor_68_68" id="FNanchor_68_68"></a><a href="#Footnote_68_68" class="fnanchor">[68]</a></p>
+
+<div class="footnote"><p><a name="Footnote_68_68" id="Footnote_68_68"></a><a href="#FNanchor_68_68"><span class="label">[68]</span></a>
+E. Duhousset, &#8216;The Horse,&#8217; Paris, 1881.</p></div>
+
+<hr class="c25" />
+<p class="pagenum"><a name="Page_282" id="Page_282">[282]</a></p>
+<h2>CHAPTER V</h2>
+
+<h3>THE PACES OF THE HORSE</h3>
+
+<p>As a completion of the studies we have just been making,
+some notions relative to the paces of the horse seem to us
+to be absolutely indicated.</p>
+
+<p>Let it be permitted to us to remind the reader in this
+connection that we have already been for twenty-one years
+occupied with this question, and that by means of an
+articulated figure, a sort of movable mannikin, we have
+endeavoured to demonstrate to artists the differences which
+characterize the various paces of the horse.<a name="FNanchor_69_69" id="FNanchor_69_69"></a><a
+href="#Footnote_69_69" class="fnanchor">[69]</a> The arrangement
+then employed cannot, evidently, be used in the
+present volume, but we will inspire ourselves, in the preparation
+of the present chapter, with the elements of demonstration
+which we have employed, and which, in the course of
+our teaching, we have had the satisfaction of seeing favourably
+received.</p>
+
+<div class="footnote"><p><a name="Footnote_69_69" id="Footnote_69_69"></a><a href="#FNanchor_69_69"><span class="label">[69]</span></a>
+&Eacute;douard Cuyer, &#8216;Les Allures du Cheval,&#8217; demonstrated with the aid
+of a coloured, separable, and articulated table, Paris, 1883.
+</p><p>
+This table was the subject of a note communicated to the Academy
+of Sciences by Professor Marey (&#8216;Comptes rendus de l&#8217;Acad&eacute;mie de
+Sciences&#8217;) at the meeting of June 26, 1882. On the other hand, it has
+been the subject of a presentation which we have had the honour of being
+permitted to make to the Academy of Fine Arts at the meeting of
+November 4, 1882.
+</p><p>
+The fasciculus in question has been since united with a more complete
+whole as regards the study of the horse. E. Cuyer and E. Alex, &#8216;Le
+Cheval: Ext&eacute;rieur, Structure et Fonctions, Races,&#8217; avec 26 planches
+colori&eacute;es, d&eacute;coup&eacute;es et superpos&eacute;es, Paris, 1886.</p></div>
+
+<p>The progressive movements by which an individual<span class="pagenum"><a name="Page_283" id="Page_283">[283]</a></span>
+transports himself from one place to another do not operate
+according to a unique method and with a constantly
+uniform velocity. These various modes of progression are
+designated under the name of <i>paces</i>.</p>
+
+<p>It is extremely difficult to analyze, by simple observation,
+the movements which characterize these gaits. Let us, for
+example, examine the displacements made by the limbs of
+a horse during that of walking; if we have no notion of these
+displacements, it will be, so to speak, impossible to determine
+in what order they are executed. The sight of the
+imprints left on the ground by the hoofs is not a sufficient
+means of demonstration, especially for artists. The noise
+made by the blows of these limbs, or by the little bells of
+different timbre suspended from them, are absolutely in the
+same case.</p>
+
+<p>Processes enabling us to fix or to register the paces are
+in every way preferable. Such really exist; they are:
+instantaneous photography and those which constitute the
+graphic method of Professor Marey. The results given by
+the photograph are certainly appreciable; but, from the
+didactic point of view, we give the preference to the graphic
+method, the general characters and the mode of application
+of which we now proceed to analyze.<a name="FNanchor_70_70" id="FNanchor_70_70"></a><a href="#Footnote_70_70" class="fnanchor">[70]</a></p>
+
+<div class="footnote"><p><a name="Footnote_70_70" id="Footnote_70_70"></a><a href="#FNanchor_70_70"><span class="label">[70]</span></a>
+We cannot too strongly recommend the reading of the excellent works
+which Professor Marey has published, and which have for their object
+the study of movements, as well as the exhibition of the procedures which
+he has employed. E. J. Marey, &#8216;La Machine Animale,&#8217; Paris, 1873;
+&#8216;La M&eacute;thode graphique dans les Sciences exp&eacute;rimentales,&#8217; Paris, 1884;
+&#8216;Le Vol des Oiseaux,&#8217; Paris, 1890; &#8216;Le Mouvement,&#8217; Paris, 1894.</p></div>
+
+<p>It is necessary to understand first of all, in this connection,
+that which relates to a man&#8217;s walking pace.</p>
+
+<div class="figmed"><a name="Fig115" id="Fig115"></a>
+<img src="images/illo309.png" alt="Fig. 115" width="400" height="251" />
+<p class="caption just">Fig. 115.&mdash;Experimental Shoes, intended to Record the
+Pressure of the Foot on the Ground.</p></div>
+
+<p>The method of Professor Marey rests on the following
+principle: Suppose two rubber globes connected with one
+another by a tube. If we compress one of these globes, the
+air which it contains will be driven into the other, and will
+afterwards return when the pressure has ceased. Nothing
+more simple, evidently; but it is necessary to describe it in
+detail in order the better to comprehend that which follows:
+The walker who is the subject of experiment is furnished
+with special shoes (<a href="#Fig115">Fig. 115</a>), having thick indiarubber
+soles,<span class="pagenum"><a name="Page_284" id="Page_284">[284]</a></span>
+hollowed in the interior, so that the whole thus constituted
+forms a sort of hollow cushion which is compressed under
+the influence of the pressure of the foot on the ground. A
+tube which is attached to a registering apparatus, which the
+person who is walking carries in his hand, communicates
+with this cavity (<a href="#Fig116">Fig. 116</a>). This apparatus is formed of a
+metal drum, which is closed at its upper part by a flexible
+membrane. Each time that one of the man&#8217;s feet presses
+on the ground, the air contained in the cavity of the sole
+of the shoe is driven into the drum, which we have just
+mentioned, and the flexible membrane of this drum is
+elevated. To this membrane is attached a vertical rod
+which supports a horizontal style.</p>
+
+<div class="figmed"><a name="Fig116" id="Fig116"></a>
+<img src="images/illo310.png" alt="Fig. 116" width="325" height="480" />
+<p class="caption just">Fig. 116.&mdash;Runner furnished with the Exploratory and
+Registering Apparatus of the Various Paces.</p></div>
+
+<p>When the membrane, as we have just seen, is elevated,
+the style is lifted, and then descends when the pressure of
+the foot ceases. It traces these displacements on a leaf of
+paper, the surface of which is covered with a thin layer of
+lamp-black, which it removes by its contact; different parts
+of this surface are successively presented to it, the paper
+being rolled round a cylinder which is turned on its axis by
+means of a clockwork movement. It is necessary to add
+that the inscription is made, in the study of the walk of man,
+by means of two styles, each corresponding to one of the
+feet.</p>
+
+<p>The tracings thus obtained, which are read from left to
+right, are sufficiently simple; but to understand them
+properly, it is necessary to remember that the style undergoes
+a movement of ascensional displacement during each
+pressure of a foot, and that, on the other hand, it descends<span class="pagenum"><a name="Page_285" id="Page_285">[285]</a></span>
+when the latter is separated from the ground. We also see,
+on the tracing which it leaves, a line which ascends and then
+descends; the meaning of this is that first the foot presses
+on the ground, and is afterwards raised from it.</p>
+
+<div class="figmed"><a name="Fig117" id="Fig117"></a>
+<img src="images/illo311.png" alt="Fig. 117" width="500" height="148" />
+<p class="caption just">Fig. 117.&mdash;Tracing of the Running of a Man (after
+Professor Marey.)</p>
+
+<p class="subcaption just">D, Pressures and elevations of the right foot; G, pressures and elevations
+of the left foot.</p></div>
+
+<p>On the tracing (<a href="#Fig117">Fig. 117</a>), the line D relates to the right
+foot; the line G, which is dotted so that it may not be confused
+with the preceding, corresponds to the left foot. The
+line G first ascends; the meaning of which is that the left
+foot presses on the ground; afterwards it descends: this
+indicates that the pressure of the foot has ceased. It is the
+same for the right foot. As we see, the pressures succeed
+each other; when the left foot touches the ground, the right
+is separated from it; when the latter presses the ground,
+it is the left which no longer rests there.</p>
+
+<p>The line O is related to the movements of the body, as<span class="pagenum"><a name="Page_286" id="Page_286">[286]</a></span>
+indicated by the oscillations of the head. We will neglect
+these.</p>
+
+<p>But this tracing, which serves us for an example, is not,
+it must indeed be said, of very easy reading; it would be
+still less so if the paces of a horse were registered, for there
+would then be four lines, the entanglement of which would
+cause greater complication.</p>
+
+<p>These difficulties of reading need be no longer feared, if
+we transform the tracing into a notation by means of the
+following diagram.</p>
+
+<div class="figmed"><a name="Fig118" id="Fig118"></a>
+<img src="images/illo312a.png" alt="Fig. 118" width="500" height="237" />
+<p class="caption center">Fig. 118.</p></div>
+
+<p>There are drawn (<a href="#Fig118">Fig. 118</a>) below the graphic tracing two
+horizontal lines (1, 2). From the point where the line D
+rises (commencement of the pressure of the right foot), and
+from the point where this same line descends (end of the
+same pressure), we let fall two vertical lines joining the two
+horizontal ones mentioned above. At this plane, and
+between the two vertical lines, we mark a broad white one
+(<i>a, b</i>). This expresses, by its length, the duration of the
+period of pressure of the right foot. In doing the same for
+the line G, we obtain for the indication of a pressure of the
+left foot an interval of the same kind, in which are marked
+cross-lines, or which is tinted gray, in order to avoid all
+confusion with the preceding tracing.</p>
+
+<p>This notation can, with sufficient exactitude, be compared
+to that which is employed in the musical scale. The horizontal
+lines 1 and 2 represent the <i>compass</i>. We there also see
+<i>notes</i>; these are the bars indicating the pressure, of which the<span class="pagenum"><a name="Page_287" id="Page_287">[287]</a></span>
+value&mdash;that is to say, the duration&mdash;is represented by the
+length of these bars. It is the same with regard to the intervals
+of <i>silence</i>: these are expressed by the intervals which
+separate the pressures, and correspond to the moments in
+which, during certain paces, such as running, the body is
+raised from the ground. Besides, we see intervals of this
+kind on the notation reproduced (<a href="#Fig118">Fig. 118</a>) relative to the
+running of man.</p>
+
+<div class="figmed"><a name="Fig119" id="Fig119"></a>
+<img src="images/illo312b.png" alt="Fig. 119" width="500" height="256" />
+<p class="caption center">Fig. 119.</p></div>
+
+<p>In order to make the signification of these tracings still
+better understood, we reproduce four varieties of them
+(<a href="#Fig119">Fig. 119</a>).</p>
+
+<p>The first notation is that of ordinary walking. The
+pressures succeed each other regularly.</p>
+
+<p><span class="pagenum"><a name="Page_288" id="Page_288">[288]</a></span>The second shows what takes place during the ascent of
+a staircase. At a certain moment, the weight of the body is
+upon both feet at the same time, one of them not quitting
+the lower step, until the other is already in contact with
+the step above. Accordingly, there is thus produced an
+overriding of the pressures.</p>
+
+<p>The third is relative to running, and has already been
+represented in <a href="#Fig118">Fig. 118</a>. The pressures of the feet are
+separated by the times of suspension.</p>
+
+<p>The fourth also represents running, but in this case
+more rapid and characterized by the shorter pressures,
+the slightly longer periods of suspension intervals, and the
+quicker succession of movements.</p>
+
+<p>Before putting aside the indications relating to the
+walking movements of man&mdash;indications which it was necessary
+to give in order to render intelligible those which are
+connected with the paces of the horse&mdash;we have yet to fix the
+value of that which we call &#8216;a step.&#8217;</p>
+
+<p>It is generally admitted that a step is constituted by the
+series of movements which are produced between the corresponding
+phases of the action of one foot and that of the
+other&mdash;for example, between the moment at which the
+right foot commences its pressure on the ground and that
+at which the left foot commences its own. It is necessary
+to adopt here another method of looking at it, and to
+regard the preceding as being but a <i>half-step</i>. The step
+should then be defined as being constituted by the series
+of movements which are executed between two similar
+positions of the same foot&mdash;as, for example, between the
+commencement of a pressure of the right foot and the
+similar phase of the following pressure of the same foot.
+We shall soon understand the importance of this definition.</p>
+
+<p>Before entering on the details of the paces of the horse,
+it is necessary to see how the limbs of the latter oscillate
+during the period of a complete step; or, which is the
+same thing, to determine what the displacements are which
+a limb executes between two similar positions of its foot.</p>
+
+<p>If we examine one of the limbs during a forward movement
+of the animal, we see that this limb passes through<span class="pagenum"><a name="Page_289" id="Page_289">[289]</a></span>
+two principal phases: (1) It is raised from the ground;
+(2) it resumes contact with the ground. Each of these
+phases is divided into three periods of time, which we
+proceed to analyze in connection with the anterior limb.</p>
+
+<div class="figmed"><a name="Fig120" id="Fig120"></a>
+<img src="images/illo314.png" alt="Fig. 120" width="350"  height="360" />
+<p class="caption just">Fig. 120.&mdash;Swing of the Raised Anterior Limb (after G. Colin).<a name="FNanchor_71_71"
+id="FNanchor_71_71"></a><a href="#Footnote_71_71" class="fnanchor">[71]</a></p>
+
+<p class="subcaption just">C, Lifting; B, suspension; A, placing.</p></div>
+
+<div class="footnote"><p><a name="Footnote_71_71" id="Footnote_71_71"></a><a href="#FNanchor_71_71"><span class="label">[71]</span></a>
+G. Colin, &#8216;Trait&eacute; de Physiologie Compar&eacute;e des Animaux,&#8217; third edition,
+Paris, 1886.</p></div>
+
+<p>The foot quits the ground (<a href="#Fig120">Fig. 120</a>, C); this may be
+called <i>lifting</i>; the limb is oblique in direction downwards
+and backwards. This same limb is flexed and carried forward
+(<a href="#Fig120">Fig. 120</a>, B), and, as it is supported by the action of
+its flexors, this is the period named <i>suspension</i>; the hoof
+is vertical. Then the limb is carried still further forward,
+becoming extended (<a href="#Fig120">Fig. 120</a>, A); the heel is lowered, and
+the foot, being oblique, is directed towards the ground;
+this is the <i>placing</i>.</p>
+
+<div class="figmed"><a name="Fig121" id="Fig121"></a>
+<img src="images/illo315.png" alt="Fig. 121" width="350" height="345" />
+<p class="caption just">Fig. 121.&mdash;Swing of the Anterior Limb on the Point of
+Pressure (after G. Colin).</p>
+
+<p class="subcaption just">A, Commencement of the pressure; B, centre of the pressure; C, termination
+of the pressure.</p></div>
+
+<p>Then takes place pressure (<a href="#Fig121">Fig. 121</a>). The foot has just
+been placed on the ground; the limb is oblique in direction
+downwards and forwards; this we call <i>commencement of the
+pressure</i> (<a href="#Fig121">Fig. 121</a>, A). Then the body, being carried forward,
+whilst the hoof, D, is fixed on the ground, the limb
+becomes vertical: this stage is <i>mid-pressure</i> (<a href="#Fig121">Fig. 121</a>,
+B).<span class="pagenum"><a name="Page_290" id="Page_290">[290]</a></span>
+Finally, the progression of the body continuing, the limb
+becomes oblique downwards and backwards; it is now at
+the <i>termination of pressure</i> (<a href="#Fig121">Fig. 121</a>, C), and proceeds to lift
+itself anew if another step is to be made.</p>
+
+<p>In conclusion, the inferior extremity of the limb describes,
+from its elevation to its being placed on the ground, an arc
+of a circle around its superior extremity (<a href="#Fig121">Fig. 121</a>, D);
+whilst, during the pressure, it is its superior extremity
+which describes one around its inferior extremity, then fixed
+on the ground (<a href="#Fig121">Fig. 121</a>, D).</p>
+
+<p>If we simultaneously examine the two fore-limbs, we
+remark that when one of them begins its pressure the
+other ends it, and <i>vice vers&acirc;</i>.</p>
+
+<div class="figmed"><a name="Fig122" id="Fig122"></a>
+<img src="images/illo316.png" alt="Fig. 122" width="350" height="306" />
+<p class="caption just">Fig. 122.&mdash;Posterior Limb, giving the Impulse (after G. Colin).</p>
+
+<p class="subcaption just">A, Commencement of pressure; B, centre of pressure; C, termination
+of pressure.</p></div>
+
+<p>As to the hind-limbs, the oscillations are similar to those
+of the fore ones. In the second half of the pressure&mdash;that
+is, when they are passing from the vertical direction (<a href="#Fig122">Fig. 122</a>,
+A) to extreme obliquity backwards (<a href="#Fig122">Fig. 122</a>, C)&mdash;the effect
+of their action is to give propulsion to the body.</p>
+
+<p>The fore and hind limbs make the same number of steps,
+and the steps have the same length.</p>
+
+<p>The limbs of any quadruped&mdash;but we make special allusion<span class="pagenum"><a name="Page_291" id="Page_291">[291]</a></span>
+to those of the horse&mdash;are divided into groups in the
+following manner:</p>
+
+<p>The anterior pair constitutes the <i>anterior biped</i>. The
+<i>posterior biped</i> is that formed by the posterior limbs.</p>
+
+<p>The name of <i>lateral biped</i> serves to designate the whole
+formed by the two limbs of the same side. The right fore-limb
+and the right hind-limb form the <i>right lateral biped</i>.
+The two others form the <i>left lateral biped</i>.</p>
+
+<p>A fore-limb and hind-limb belonging to the opposite side
+form a <i>diagonal biped</i>, which also takes the name of the fore-limb
+which forms a part of it. Thus, <i>the right diagonal biped</i>
+is formed by the association of the right fore-limb and the
+left hind one. The <i>left diagonal biped</i> is, consequently, the
+inverse.</p>
+
+<p>It is necessary to remember well these preliminary indications;
+it is the only means of comprehending with facility
+that which is about to follow.</p>
+
+<p>Let us first return to the grouping of the limbs. The
+denominations <i>anterior</i> and <i>posterior bipeds</i> render
+clearly<span class="pagenum"><a name="Page_292" id="Page_292">[292]</a></span>
+perceptible the comparison which consists in regarding a
+horse when walking as capable of being represented by two
+men marching one behind the other, and making the same
+number of steps. According as they move the legs of the
+same side at the same time in &#8216;covering the step,&#8217; or march
+in contretemps step, we find reproduced all the rhythms
+which characterize the different paces of the horse.</p>
+
+<div class="figmed"><a name="Fig123" id="Fig123"></a>
+<img src="images/illo317.png" alt="Fig. 123" width="500" height="115" />
+<p class="caption just">Fig. 123.&mdash;Notation of the Ambling Gait in the Horse (after
+Professor Marey).</p></div>
+
+<p>Professor Marey has studied these paces by a similar
+method to that which he adopted for the walking of man,
+and which we have already described. He employed hollow
+balls fixed under the hoofs, and a registering apparatus
+with four styles, each corresponding to one of the limbs.
+The tracing obtained is rather complicated, since two sets
+of lines are found marked. But a notation similar to
+that of which we have spoken can be discovered, and its
+exact signification should now be determined. For this
+purpose, we have selected the most simple (see <a href="#Fig123">Fig. 123</a>).
+We there see, placed in two superimposed lines, the
+pressure markings of the right feet (white bands), and of
+the left feet (gray bands). On the upper line are found
+those related to the fore-legs; the lower lines contain those
+associated with the hind-legs. It is, in brief, the superposition
+of two notations of the human walking movements.
+And seeing that, as we have previously pointed out, we may
+make a comparison between a quadruped and two men
+placed one behind the other, it is easy to understand the
+significance of the superimposed notations, if we accustom
+ourselves to look on them as the notations of two bipeds.</p>
+
+<p>To read these notations&mdash;that is, to learn to know what
+occurs at each of the movements of the pace&mdash;it is necessary,
+indeed, to remember that they should be examined in<span class="pagenum"><a name="Page_293" id="Page_293">[293]</a></span>
+vertical sections; it is to each of these sections&mdash;of these
+vertical divisions&mdash;that each of the movements which we
+more particularly wish to analyze corresponds.</p>
+
+<p>We proceed to study first the pace of ambling, because it
+is the most simple; we shall then consider the trot, and,
+finally, we shall examine that which is the most complicated,
+viz., the step.</p>
+
+<p><b>The Amble.</b>&mdash;To give an exact idea of the general
+character of the amble, let us fancy the two men whom
+we discussed above marching one behind the other and
+walking in step&mdash;that is, moving the legs of the same side
+simultaneously. They will thus represent the amble, which,
+indeed, results from the alternate displacements of the
+lateral bipeds; the limbs of the same side (right or left)
+execute the same movements in the same time.</p>
+
+<p>This is what the notation indicates (<a href="#Fig123">Fig. 123</a>). We there
+see that the pressures of the right fore-foot, marked by the
+white bands in the upper range, are exactly superposed on
+those of the right hind one, which are marked by a similar
+band on the lower line; this means that the pressures<span class="pagenum"><a name="Page_294" id="Page_294">[294]</a></span>
+took place in the same time. We there see also a similar
+arrangement of the gray bands, which has a similar significance
+for the left fore and hind feet.</p>
+
+<div class="figmed"><a name="Fig124" id="Fig124"></a>
+<img src="images/illo318.png" alt="Fig. 124" width="350" height="296" />
+<p class="caption center">Fig. 124.&mdash;The Amble: Right Lateral Pressure.<a name="FNanchor_72_72"
+id="FNanchor_72_72"></a><a href="#Footnote_72_72" class="fnanchor">[72]</a></p></div>
+
+<div class="footnote"><p><a name="Footnote_72_72" id="Footnote_72_72"></a><a href="#FNanchor_72_72"><span class="label">[72]</span></a>
+The figures which, in the present study, reproduce the different paces,
+have been made from our articulated horse (see the note on <a href="#Page_282">p. 282</a>).</p></div>
+
+<p>And if we recollect the three phases of pressure (see
+<a href="#Page_289">p. 289</a>, and <a href="#Fig121">Figs. 121</a>, <a href="#Fig122">122</a>), we shall comprehend, in
+looking at the diagrams, that, at the initial stage (A),
+the limbs are commencing their pressure, and are oblique
+downwards and forwards; that afterwards (B) the two
+limbs are vertical, since they are at the middle of the
+pressure stage; and that finally (C) they are oblique
+downwards and backwards, for it is then the termination
+of their pressure (<a href="#Fig124">Fig. 124</a>).</p>
+
+<p>During the time that the right limbs are pressing
+(notation, white bands) the left limbs are raised; afterwards
+these latter take up the pressure (gray bands), and
+then the right limbs are raised in their turn.</p>
+
+<p>During the pace of ambling the weight of the body, which
+is wholly sustained by the limbs of one side only, is not
+in equilibrium, so that the limbs which are raised return
+by a brisk movement to the position of support in order to
+re-establish it.</p>
+
+<p><b>The Trot.</b>&mdash;We have just seen that, in order to represent
+the amble, the two marchers moved their right limbs
+simultaneously, and then their left ones.</p>
+
+<p>Let us suppose now that the hinder man anticipated
+by half a pace the movement of the front one, then
+will be found realized the association and the nature
+of the displacements of the limbs during the pace of the
+trot.</p>
+
+<p>By this anticipation of a half-step (we have defined,
+<a href="#Page_288">p. 288</a>, what is to be understood by the word
+<i>step</i>), it<span class="pagenum"><a name="Page_295" id="Page_295">[295]</a></span>
+follows that when the marcher who is in front advances
+his right leg it is the left leg of the marcher who follows
+him that is carried in the same direction. We should
+thus conclude from this that the trot is characterized
+by a succession of displacements of the diagonal bipeds.</p>
+
+<div class="figmed"><a name="Fig125" id="Fig125"></a>
+<img src="images/illo319.png" alt="Fig. 125" width="500" height="115" />
+<p class="caption just">Fig. 125.&mdash;Notation of the Gait of the Trot in the Horse
+(after Professor Marey).</p></div>
+
+<div class="figmed"><a name="Fig126" id="Fig126"></a>
+<img src="images/illo320a.png" alt="Fig. 126" width="350" height="285" />
+<p class="caption center">Fig. 126.&mdash;The Trot; Right Diagonal Pressure.</p></div>
+
+<p><span class="pagenum"><a name="Page_296" id="Page_296">[296]</a></span>Indeed,
+if we examine the notation of this gait (<a href="#Fig125">Fig. 125</a>),
+we see that with the pressure of the right fore-foot is found
+associated the pressure of the left hind-foot. It is, accordingly,
+a typical diagonal biped (<a href="#Fig126">Fig. 126</a>).</p>
+
+<div class="figmed"><a name="Fig127" id="Fig127"></a>
+<img src="images/illo320b.png" alt="Fig. 127" width="350" height="276" />
+<p class="caption center">Fig. 127.&mdash;The Trot; Time of Suspension.</p></div>
+
+<p>But it is necessary to add that these groups of pressures
+do not succeed one another without interruption, except
+in the slow trot. In the ordinary trot, or in that in which
+the animal&#8217;s strides are very long, the body between each
+of the double pressures which we have just been considering
+is projected forward with such force that it remains for
+an instant separated from the ground. This is what we
+designate by the name of <i>time of suspension</i> (<a href="#Fig127">Fig. 127</a>). The
+notation in this case would be slightly different from that
+which we reproduce above, in this sense: that between the
+diagonal pressures there then would be found an interval,
+since during the time the body is suspended none of the
+feet can produce a pressure-mark (see, with regard to
+these intervals, the notations of the running of a man,
+<a href="#Fig118">Fig. 118</a>, and <a href="#Fig119">Fig. 119</a>, 3, 4).</p>
+
+<p><b>The Walk.</b>&mdash;Although slow, a feature which would seem
+to make it possible to permit its analysis in a horse when
+walking, this pace is difficult to comprehend without
+sufficient preliminary study.</p>
+
+<p>We saw above that in order to represent the amble the
+marchers had to move the legs of the same side simultaneously.
+We have also just seen that in order to represent
+the trot the marcher at the back had to anticipate
+by a half-step. Suppose, now, that this same marcher
+anticipates the man in front by a quarter-step only, or by<span class="pagenum"><a name="Page_297" id="Page_297">[297]</a></span>
+a half-pressure period, and thus will be found realized the
+order of succession of the limbs in the gait or pace called
+the <i>walk</i>. The feet meet the ground one after the other,
+since they are each in advance by half the duration of a
+pressure. The strokes are four in number during the period
+of a step of this pace; in the amble and in the trot they do<span class="pagenum"><a name="Page_298" id="Page_298">[298]</a></span>
+not exceed two, for then the limbs strike the ground in
+lateral diagonal pairs.</p>
+
+<div class="figmed"><a name="Fig128" id="Fig128"></a>
+<img src="images/illo321.png" alt="Fig. 128" width="500" height="140" />
+<p class="caption just">Fig. 128.&mdash;Notation of the Pace of Stepping in the Horse
+(after Professor Marey).</p>
+
+<p class="subcaption just">L, Right lateral pressure; D, right diagonal pressure; L&#8242;, left lateral
+pressure; D&#8242;, left diagonal pressure.</p></div>
+
+<p>If we examine the notation of the pace of walking
+(<a href="#Fig128">Fig. 128</a>), we see that the right fore-foot commences
+its<span class="pagenum"><a name="Page_299" id="Page_299">[299]</a></span>
+pressure when the right hind-foot is in the middle of its
+own, and that the hinder left begins in the middle of that
+of the right fore-foot, and that it is itself at the midst of its
+pressure when the left fore-foot touches the ground, etc.<span class="pagenum"><a name="Page_300" id="Page_300">[300]</a></span>
+In a word, the foot-fallings occur in the following order
+and at regular intervals&mdash;the fore right foot is here considered
+as acting first: right fore, left hind, left fore, right
+hind, and so on in succession.</p>
+
+<p>As to the nature of the bipeds which succeed one another,
+it is easy to understand them by means of the notation.
+In reading this from left to right, we see that the associations
+of pressure are first made by the two right feet, then by a
+right foot and a left one, then by two left feet, and, finally,
+by a left and right. It is, accordingly, a succession this time
+of lateral and diagonal pressures.</p>
+
+<div class="figmed"><a name="Fig129" id="Fig129"></a>
+<img src="images/illo322a.png" alt="Fig. 129" width="350" height="285" />
+<p class="caption center">Fig. 129.&mdash;The Step: Right Lateral Pressure.</p></div>
+
+<div class="figmed"><a name="Fig130" id="Fig130"></a>
+<img src="images/illo322b.png" alt="Fig. 130" width="350" height="283" />
+<p class="caption center">Fig. 130.&mdash;The Step: Right Diagonal Pressure.</p></div>
+
+<p>Thus, we find at the start a right lateral pressure
+(<a href="#Fig129">Fig. 129</a>), next a right diagonal (<a href="#Fig130">Fig. 130</a>), then a left lateral;
+finally, a left diagonal pressure. It is thus that the initial
+letters L, D, L&#8242;, D&#8242; further indicate the notations represented
+in <a href="#Fig128">Fig. 128</a>.</p>
+
+<div class="figmed"><a name="Fig131" id="Fig131"></a>
+<img src="images/illo323a.png" alt="Fig. 131" width="350" height="308" />
+<p class="caption center">Fig. 131.&mdash;The Gallop: First Period.</p></div>
+
+<div class="figmed"><a name="Fig132" id="Fig132"></a>
+<img src="images/illo323b.png" alt="Fig. 132" width="350" height="281" />
+<p class="caption center">Fig. 132.&mdash;The Gallop: Second Period.</p></div>
+
+<div class="figmed"><a name="Fig133" id="Fig133"></a>
+<img src="images/illo324a.png" alt="Fig. 133" width="350" height="251" />
+<p class="caption center">Fig. 133.&mdash;The Gallop: Third Period.</p></div>
+
+<div class="figmed"><a name="Fig134" id="Fig134"></a>
+<img src="images/illo324b.png" alt="Fig. 134" width="350" height="224" />
+<p class="caption center">Fig. 134.&mdash;The Gallop: Time of Suspension.</p></div>
+
+<p><b>The Gallop.</b>&mdash;The ordinary gallop is a pace of three
+phases. The first is characterized by the fact that one
+hind-limb alone rests on the ground (<a href="#Fig131">Fig. 131</a>); in
+the<span class="pagenum"><a name="Page_301" id="Page_301">[301]</a></span>
+second the animal is on a diagonal support (<a href="#Fig132">Fig. 132</a>); in
+the third it comes down on a fore-limb (<a href="#Fig133">Fig. 133</a>). The
+body is then raised (<a href="#Fig134">Fig. 134</a>), and to this period of suspension
+succeed anew the three modes of pressure indicated
+above.</p>
+
+<p>The gallop is said to be from either right or left. In the
+gallop from the right, the right fore-leg is the more frequently
+in advance of its neighbour; it is the last to be
+placed on the ground. The left foot of the posterior biped
+is the one which commences the action.</p>
+
+<p>An entirely opposite arrangement characterizes the
+gallop from the left.</p>
+
+<div class="figmed"><a name="Fig135" id="Fig135"></a>
+<img src="images/illo325a.png" alt="Fig. 135" width="500" height="135" />
+<p class="caption just">Fig. 135.&mdash;Notation of the Gallop divided into Three Periods
+of Time (after Professor Marey).</p>
+
+<p class="subcaption just">1, First period; 2, second period; 3, third period.</p></div>
+
+<p>The notation reproduced in <a href="#Fig135">Fig. 135</a> corresponds to the
+gallop from the right. It is there seen, as we pointed out
+above, that in the first phase the exclusive support of the
+left hind-foot takes place (1); that afterwards, in the
+second, commence simultaneously, the pressures of the left
+fore and the right hind foot (2); this is the left diagonal
+support; and that finally, in the third, the body comes
+down on a fore-limb, which is then the right (3); and
+that for a moment it is on this limb alone that the animal
+rests.</p>
+
+<p>To these three phases on the notation succeeds an
+interval; this is the period of suspension.</p>
+
+<div class="figmed"><a name="Fig136" id="Fig136"></a>
+<img src="images/illo325b.png" alt="Fig. 136" width="500" height="135" />
+<p class="caption just">Fig. 136.&mdash;Notation of the Gallop of Four Periods in the
+Horse (after Professor Marey).</p>
+
+<p class="subcaption just">1, First period; 2, second period; 3, third period; 4, fourth period.</p></div>
+
+<p>The gallop of four phases only differs from the preceding<span class="pagenum"><a name="Page_302"
+id="Page_302"></a></span><span class="pagenum"><a name="Page_303" id="Page_303"></a></span><span
+class="pagenum"><a name="Page_304" id="Page_304">[304]</a></span>
+in that the foot-fallings of each diagonal biped occur at
+slight intervals, and give distinct sounds. The notation is
+reproduced in <a href="#Fig136">Fig. 136</a>.</p>
+
+<p><b>The Leap.</b>&mdash;The leap is an act by which the body is
+wholly raised from the ground and projected upwards and
+forwards to a greater or less distance.</p>
+
+<p>It is prepared for by the flexing of the hind-limbs, which,
+by being suddenly extended, project the body, and thus
+enable it to pass over an obstacle.</p>
+
+<div class="figmed"><a name="Fig137" id="Fig137"></a>
+<img src="images/illo326.png" alt="Fig. 137" width="500" height="229" />
+<p class="caption center">Fig. 137.&mdash;Leap of the Hare (after G. Colin).</p></div>
+
+<p>This preparatory arrangement is very remarkable in the
+leap of the lion, the cat, and the panther, which execute
+springs of great length; in the horse, in which the leap
+is not an habitual mode of progression, this flexion of the
+hinder limbs is less marked. With this animal the leap is
+generally associated with the gallop; nevertheless, it is
+sometimes made from a stationary position. In observing
+the hare or the rabbit, in which the leap is habitual, we
+notice (<a href="#Fig137">Fig. 137</a>) that the hind-limbs, being extremely
+flexed, rest on the ground as far as the calcaneum, are
+then straightened by the action of their extensors, become
+vertical and then oblique backwards at the moment the
+body is thrown forward into space by the sudden extension
+of these limbs.</p>
+
+<p>The action of the extensors is energetic and instantaneous,
+and their energy is greater than in ordinary progression,
+for it is required to lift the body and to project
+it forcibly a more or less considerable distance. It is
+the extreme rapidity of this action which enables the
+animal to clear an obstacle, for without this condition
+the body would be raised, but not separated from the
+ground.</p>
+
+<p>First of all, in reaching the obstacle to be cleared, the
+horse prepares to leap by taking the attitude of rearing;
+the hind-limbs are flexed and carried under the body, the
+fore-quarters are raised, and the different segments of the
+fore-limbs are flexed (<a href="#Fig138">Fig. 138</a>).</p>
+
+<div class="figmed"><a name="Fig138" id="Fig138"></a>
+<img src="images/illo327a.png" alt="Fig. 138" width="350" height="362" />
+<p class="caption center">Fig. 138.&mdash;The Leap.</p></div>
+
+<div class="figmed"><a name="Fig139" id="Fig139"></a>
+<img src="images/illo327b.png" alt="Fig. 139" width="350" height="402" />
+<p class="caption center">Fig. 139.&mdash;The Leap.</p></div>
+
+<div class="figmed"><a name="Fig140" id="Fig140"></a>
+<img src="images/illo328a.png" alt="Fig. 140" width="350" height="324" />
+<p class="caption center">Fig. 140.&mdash;The Leap.</p></div>
+
+<div class="figmed"><a name="Fig141" id="Fig141"></a>
+<img src="images/illo328b.png" alt="Fig. 141" width="350" height="269" />
+<p class="caption center">Fig. 141.&mdash;The Leap.</p></div>
+
+<div class="figmed"><a name="Fig142" id="Fig142"></a>
+<img src="images/illo330a.png" alt="Fig. 142" width="350" height="257" />
+<p class="caption center">Fig. 142.&mdash;The Leap.</p></div>
+
+<div class="figmed"><a name="Fig143" id="Fig143"></a>
+<img src="images/illo330b.png" alt="Fig. 143"  width="350" height="279" />
+<p class="caption center">Fig. 143.&mdash;The Leap.</p></div>
+
+<p>One sudden trigger action produced by the violent contraction
+of the extensors of the hind-legs then takes place,
+and the animal is projected forwards, while he flexes the<span class="pagenum"><a name="Page_305" id="Page_305">[305]</a></span>
+fore-legs more and more (<a href="#Fig139">Fig. 139</a>). He has then risen above
+the obstacle (<a href="#Fig140">Fig. 140</a>). Then while he makes the downward
+and forward balancing movement, and points his
+fore-limbs in the same direction, he flexes the hind ones<span class="pagenum"><a name="Page_306" id="Page_306">[306]</a></span>
+(<a href="#Fig141">Fig. 141</a>). Whilst the latter are further flexed, in order to pass
+the obstacle in their turn, the fore-limbs which are extended
+come into contact with the ground (<a href="#Fig142">Fig. 142</a>). Finally, in
+the last phase of the leap, the animal, raising himself in
+front, after the impact of his hind-feet has taken place
+(<a href="#Fig143">Fig. 143</a>), prepares to continue the pace at which he
+progressed before meeting the obstacle which he had to
+clear.</p>
+
+<p class="fsize125 center" style="margin-top: 2em; margin-bottom: 2em;">THE END</p>
+
+<p class="fsize80 center" style="margin-top: 2em; margin-bottom: 2em;"><span class="bt"><i>London:
+Bailli&egrave;re, Tindall and Cox, 8, Henrietta Street, Covent Garden, W.C.</i></span></p>
+
+<hr class="c25" />
+<p class="pagenum"><a name="Page_307" id="Page_307">[307]</a></p>
+<p class="center fsize150">THE<br />
+<span class="fsize125">ARTISTIC ANATOMY OF ANIMALS</span></p>
+
+<div class="figlarge">
+<img src="images/illo332.png" alt="Shot lionesse" width="600" height="373" /></div>
+
+<hr class="c25" />
+<p class="pagenum"><a name="Page_308" id="Page_308"></a></p>
+<p class="pagenum"><a name="Page_309" id="Page_309">[309]</a></p>
+<h2><a name="SectionToC" id="SectionToC"></a>SECTIONAL INDEX</h2>
+
+<table summary="Sectional Index">
+
+<tr>
+<td colspan="4">&nbsp;</td>
+<td class="right fsize80">PAGE</td>
+</tr>
+
+<tr>
+<td colspan="4" class="left"><b>Generalities of Comparative Anatomy</b></td>
+<td class="right bot"><a href="#Page_1">1</a></td>
+</tr>
+
+<tr>
+<td colspan="5" class="center" style="padding: 1em 0;">OSTEOLOGY AND ARTHROLOGY</td>
+</tr>
+
+<tr>
+<td colspan="5" class="left"><b>The Trunk:</b></td>
+</tr>
+
+<tr>
+<td style="width: 1em;">&nbsp;</td>
+<td colspan="3" class="left top"><i>Vertebral Column</i></td>
+<td class="right bot"><a href="#Page_4">4</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td style="width: 1em;">&nbsp;</td>
+<td colspan="2" class="left top">Sacrum</td>
+<td class="right bot"><a href="#Page_10">10</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Coccygeal vertebr&aelig;</td>
+<td class="right bot"><a href="#Page_11">11</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Direction and form of the vertebral column</td>
+<td class="right bot"><a href="#Page_11">11</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top"><i>Thorax</i></td>
+<td class="right bot"><a href="#Page_12">12</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Sternum</td>
+<td class="right bot"><a href="#Page_14">14</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Ribs and costal cartilages</td>
+<td class="right bot"><a href="#Page_14">14</a></td>
+</tr>
+
+<tr>
+<td colspan="5" class="left"><b>The Anterior Limbs:</b></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top"><i>Shoulder</i></td>
+<td class="right bot"><a href="#Page_20">20</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Scapula</td>
+<td class="right bot"><a href="#Page_21">21</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Clavicle</td>
+<td class="right bot"><a href="#Page_25">25</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top"><i>Arm</i></td>
+<td class="right bot"><a href="#Page_28">28</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Humerus</td>
+<td class="right bot"><a href="#Page_28">28</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">General view of the form of the forearm and hand</td>
+<td class="right bot"><a href="#Page_34">34</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Forearm</td>
+<td class="right bot"><a href="#Page_38">38</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Hand</td>
+<td class="right bot"><a href="#Page_44">44</a></td>
+</tr>
+
+<tr>
+<td colspan="5" class="left"><b>The Anterior Limbs in Certain Animals:</b></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top"><i>Plantigrades</i>: Bear</td>
+<td class="right bot"><a href="#Page_49">49</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top"><i>Digitigrades</i>: Cat, dog</td>
+<td class="right bot"><a href="#Page_51">51</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top"><i>Unguligrades</i>: Pig</td>
+<td class="right bot"><a href="#Page_57">57</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Sheep, Ox</td>
+<td class="right bot"><a href="#Page_60">60</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Horse</td>
+<td class="right bot"><a href="#Page_64">64</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Proportions of the arm, the forearm, and metacarpus</td>
+<td class="right bot"><a href="#Page_70">70</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Articulations of the anterior limbs</td>
+<td class="right bot"><a href="#Page_71">71</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Scapulo-humeral articulation</td>
+<td class="right bot"><a href="#Page_72">72</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Humero-ulnar articulation, or elbow</td>
+<td class="right bot"><a href="#Page_74">74</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Radio-ulnar articulation</td>
+<td class="right bot"><a href="#Page_75">75</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Articulation of the wrist</td>
+<td class="right bot"><a href="#Page_75">75</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Metacarpo-phalangeal articulations</td>
+<td class="right bot"><a href="#Page_76">76</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Interphalangeal articulations</td>
+<td class="right bot"><a href="#Page_77">77</a></td>
+</tr>
+
+<tr>
+<td colspan="5" class="left top"><span class="pagenum"><a name="Page_310" id="Page_310">[310]</a></span><b>The Posterior Limbs:</b></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top"><i>Pelvis</i></td>
+<td class="right bot"><a href="#Page_78">78</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Iliac bone</td>
+<td class="right bot"><a href="#Page_78">78</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top"><i>The Thigh</i></td>
+<td class="right bot"><a href="#Page_83">83</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Femur</td>
+<td class="right bot"><a href="#Page_83">83</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Knee-cap</td>
+<td class="right bot"><a href="#Page_85">85</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top"><i>The Leg</i></td>
+<td class="right bot"><a href="#Page_85">85</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Tibia</td>
+<td class="right bot"><a href="#Page_86">86</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Fibula</td>
+<td class="right bot"><a href="#Page_87">87</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top"><i>The Foot</i></td>
+<td class="right bot"><a href="#Page_87">87</a></td>
+</tr>
+
+<tr>
+<td colspan="5" class="left"><b>The Posterior Limbs in Some Animals:</b></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top"><i>Plantigrades</i>: Bear</td>
+<td class="right bot"><a href="#Page_90">90</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top"><i>Digitigrades</i>: Cat, dog</td>
+<td class="right bot"><a href="#Page_91">91</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top"><i>Unguligrades</i>: Pig</td>
+<td class="right bot"><a href="#Page_94">94</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Sheep, ox</td>
+<td class="right bot"><a href="#Page_95">95</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Horse</td>
+<td class="right bot"><a href="#Page_99">99</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Articulations of the posterior limbs</td>
+<td class="right bot"><a href="#Page_105">105</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Coxo-femoral articulation</td>
+<td class="right bot"><a href="#Page_105">105</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Femoro-tibial articulation, or knee</td>
+<td class="right bot"><a href="#Page_106">106</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Tibio-tarsal articulation, and of the bones of the tarsus</td>
+<td class="right bot"><a href="#Page_107">107</a></td>
+</tr>
+
+<tr>
+<td colspan="5" class="left"><b>The Head in General, and in Some Animals in Particular:</b></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Direction of the head</td>
+<td class="right bot"><a href="#Page_109">109</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">The skull</td>
+<td class="right bot"><a href="#Page_112">112</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">The face</td>
+<td class="right bot"><a href="#Page_118">118</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">The skull of birds</td>
+<td class="right bot"><a href="#Page_127">127</a></td>
+</tr>
+
+<tr>
+<td colspan="5" class="center" style="padding: 1em 0;">MYOLOGY</td>
+</tr>
+
+<tr>
+<td colspan="5" class="left"><b>Muscles of the Trunk:</b></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Pectoralis major</td>
+<td class="right bot"><a href="#Page_131">131</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Pectoralis minor</td>
+<td class="right bot"><a href="#Page_133">133</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Serratus magnus</td>
+<td class="right bot"><a href="#Page_134">134</a></td>
+</tr>
+
+<tr>
+<td colspan="5" class="left"><b>Muscles of the Abdomen:</b></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">External oblique</td>
+<td class="right bot"><a href="#Page_136">136</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Internal oblique</td>
+<td class="right bot"><a href="#Page_137">137</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Transversalis abdominis</td>
+<td class="right bot"><a href="#Page_138">138</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Rectus abdominis</td>
+<td class="right bot"><a href="#Page_138">138</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Pyramidalis abdominis</td>
+<td class="right bot"><a href="#Page_139">139</a></td>
+</tr>
+
+<tr>
+<td colspan="5" class="left"><b>Muscles of the Back:</b></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Trapezius</td>
+<td class="right bot"><a href="#Page_140">140</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Latissimus dorsi</td>
+<td class="right bot"><a href="#Page_142">142</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Rhomboid</td>
+<td class="right bot"><a href="#Page_144">144</a></td>
+</tr>
+
+<tr>
+<td colspan="4" class="left"><b>The Cutaneous Muscle of the Trunk</b></td>
+<td class="right bot"><a href="#Page_147">147</a></td>
+</tr>
+
+<tr>
+<td colspan="5" class="left"><b>The Coccygeal Region:</b></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Ischio-coccygeal muscle</td>
+<td class="right bot"><a href="#Page_149">149</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Superior sacro-coccygeal muscle</td>
+<td class="right bot"><a href="#Page_150">150</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top"><span class="pagenum"><a name="Page_311" id="Page_311">[311]</a></span>Lateral sacro-coccygeal muscle</td>
+<td class="right bot"><a href="#Page_150">150</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Inferior sacro-coccygeal muscle</td>
+<td class="right bot"><a href="#Page_150">150</a></td>
+</tr>
+
+<tr>
+<td colspan="5" class="left"><b>Muscles of the Neck:</b></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Mastoido-humeralis</td>
+<td class="right bot"><a href="#Page_150">150</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Sterno-mastoid</td>
+<td class="right bot"><a href="#Page_153">153</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Omo-trachelian</td>
+<td class="right bot"><a href="#Page_155">155</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Levator anguli scapul&aelig;</td>
+<td class="right bot"><a href="#Page_156">156</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Splenius</td>
+<td class="right bot"><a href="#Page_158">158</a></td>
+</tr>
+
+<tr>
+<td colspan="5" class="left"><b>Infrahyoid Muscles:</b></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Sterno-thyroid and sterno-hyoid</td>
+<td class="right bot"><a href="#Page_160">160</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Omo-hyoid</td>
+<td class="right bot"><a href="#Page_160">160</a></td>
+</tr>
+
+<tr>
+<td colspan="5" class="left"><b>Suprahyoid Muscles:</b></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Mylo-hyoid</td>
+<td class="right bot"><a href="#Page_161">161</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Digastric</td>
+<td class="right bot"><a href="#Page_161">161</a></td>
+</tr>
+
+<tr>
+<td colspan="4" class="left"><b>Panniculus of the Neck</b></td>
+<td class="right bot"><a href="#Page_162">162</a></td>
+</tr>
+
+<tr>
+<td colspan="5" class="left"><b>Muscles of the Anterior Limbs:</b></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top"><i>Muscles of the Shoulder</i></td>
+<td class="right bot"><a href="#Page_162">162</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Deltoid</td>
+<td class="right bot"><a href="#Page_162">162</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Subscapularis</td>
+<td class="right bot"><a href="#Page_163">163</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Supraspinatus</td>
+<td class="right bot"><a href="#Page_164">164</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Infraspinatus</td>
+<td class="right bot"><a href="#Page_165">165</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Teres minor</td>
+<td class="right bot"><a href="#Page_166">166</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Teres major</td>
+<td class="right bot"><a href="#Page_166">166</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Panniculus muscle of the shoulder</td>
+<td class="right bot"><a href="#Page_167">167</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top"><i>Muscles of the Arm</i></td>
+<td class="right bot"><a href="#Page_168">168</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Anterior region</td>
+<td class="right bot"><a href="#Page_169">169</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td style="width: 1em;">&nbsp;</td>
+<td class="left top">Biceps</td>
+<td class="right bot"><a href="#Page_169">169</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Brachialis anticus</td>
+<td class="right bot"><a href="#Page_170">170</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Coraco-brachialis</td>
+<td class="right bot"><a href="#Page_170">170</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Posterior region</td>
+<td class="right bot"><a href="#Page_171">171</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Triceps</td>
+<td class="right bot"><a href="#Page_171">171</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top"><i>Supplemental or Accessory Muscle of the Latissimus Dorsi</i></td>
+<td class="right bot"><a href="#Page_173">173</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top"><i>Muscles of the Forearm</i></td>
+<td class="right bot"><a href="#Page_174">174</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Anterior and external region</td>
+<td class="right bot"><a href="#Page_176">176</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Supinator longus</td>
+<td class="right bot"><a href="#Page_176">176</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">First and second external radial</td>
+<td class="right bot"><a href="#Page_176">176</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Supinator brevis</td>
+<td class="right bot"><a href="#Page_179">179</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Extensor communis digitorum</td>
+<td class="right bot"><a href="#Page_179">179</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Extensor minimi digiti</td>
+<td class="right bot"><a href="#Page_183">183</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Posterior ulnar</td>
+<td class="right bot"><a href="#Page_185">185</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Anconeus</td>
+<td class="right bot"><a href="#Page_185">185</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Long abductor of the thumb</td>
+<td class="right bot"><a href="#Page_186">186</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Short extensor of the thumb</td>
+<td class="right bot"><a href="#Page_187">187</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Long extensor of the thumb</td>
+<td class="right bot"><a href="#Page_187">187</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Proper extensor of the index</td>
+<td class="right bot"><a href="#Page_187">187</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top"><span class="pagenum"><a name="Page_312" id="Page_312">[312]</a></span>Internal and posterior region</td>
+<td class="right bot"><a href="#Page_188">188</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Pronator teres</td>
+<td class="right bot"><a href="#Page_188">188</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Flexor carpi radialis</td>
+<td class="right bot"><a href="#Page_189">189</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Palmaris longus</td>
+<td class="right bot"><a href="#Page_189">189</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Anterior ulnar</td>
+<td class="right bot"><a href="#Page_191">191</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Superficial flexor of the digits</td>
+<td class="right bot"><a href="#Page_193">193</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Long proper flexor of the thumb</td>
+<td class="right bot"><a href="#Page_197">197</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Pronator quadratus</td>
+<td class="right bot"><a href="#Page_198">198</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top"><i>Muscles of the Hand</i></td>
+<td class="right bot"><a href="#Page_199">199</a></td>
+</tr>
+
+<tr>
+<td colspan="5" class="left"><b>Muscles of the Posterior Limbs:</b></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top"><i>Muscles of the Pelvis</i></td>
+<td class="right bot"><a href="#Page_200">200</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Gluteus medius</td>
+<td class="right bot"><a href="#Page_200">200</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Gluteus maximus</td>
+<td class="right bot"><a href="#Page_201">201</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top"><i>Muscles of the Thigh</i></td>
+<td class="right bot"><a href="#Page_204">204</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Muscles of the posterior region</td>
+<td class="right bot"><a href="#Page_205">205</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Biceps</td>
+<td class="right bot"><a href="#Page_205">205</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Semi-tendinosus</td>
+<td class="right bot"><a href="#Page_206">206</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Semi-membranosus</td>
+<td class="right bot"><a href="#Page_207">207</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Muscles of the anterior region</td>
+<td class="right bot"><a href="#Page_210">210</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Triceps</td>
+<td class="right bot"><a href="#Page_210">210</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Tensor fascia lata</td>
+<td class="right bot"><a href="#Page_211">211</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Sartorius</td>
+<td class="right bot"><a href="#Page_211">211</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Muscles of the internal region</td>
+<td class="right bot"><a href="#Page_213">213</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Gracilis</td>
+<td class="right bot"><a href="#Page_213">213</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top"><i>Muscles of the Leg</i></td>
+<td class="right bot"><a href="#Page_213">213</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Muscles of the anterior region</td>
+<td class="right bot"><a href="#Page_214">214</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Tibialis anticus</td>
+<td class="right bot"><a href="#Page_214">214</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Extensor proprius pollicis</td>
+<td class="right bot"><a href="#Page_219">219</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Extensor longus digitorum</td>
+<td class="right bot"><a href="#Page_219">219</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Peroneus tertius</td>
+<td class="right bot"><a href="#Page_224">224</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Muscles of the external region</td>
+<td class="right bot"><a href="#Page_224">224</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Peroneus longus</td>
+<td class="right bot"><a href="#Page_224">224</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Peroneus brevis</td>
+<td class="right bot"><a href="#Page_225">225</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Muscles of the posterior region</td>
+<td class="right bot"><a href="#Page_227">227</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Gastrocnemius</td>
+<td class="right bot"><a href="#Page_227">227</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Soleus</td>
+<td class="right bot"><a href="#Page_228">228</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Plantaris</td>
+<td class="right bot"><a href="#Page_228">228</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Popliteus</td>
+<td class="right bot"><a href="#Page_228">228</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Superficial flexor of the toes</td>
+<td class="right bot"><a href="#Page_229">229</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Flexor longus digitorum</td>
+<td class="right bot"><a href="#Page_230">230</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Tibialis posticus</td>
+<td class="right bot"><a href="#Page_230">230</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Flexor longus pollicis</td>
+<td class="right bot"><a href="#Page_231">231</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top"><i>Muscles of the Foot</i></td>
+<td class="right bot"><a href="#Page_231">231</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Dorsalis pedis</td>
+<td class="right bot"><a href="#Page_231">231</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top"><span class="pagenum"><a name="Page_313" id="Page_313">[313]</a></span><i>Muscles of the Head</i></td>
+<td class="right bot"><a href="#Page_232">232</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Masticatory muscles</td>
+<td class="right bot"><a href="#Page_232">232</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Masseter</td>
+<td class="right bot"><a href="#Page_232">232</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Temporal muscle</td>
+<td class="right bot"><a href="#Page_234">234</a></td>
+</tr>
+
+<tr>
+<td colspan="2">&nbsp;</td>
+<td colspan="2" class="left top">Cutaneous muscles of the head</td>
+<td class="right bot"><a href="#Page_234">234</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Occipito-frontalis</td>
+<td class="right bot"><a href="#Page_234">234</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Orbicularis palpebrarum</td>
+<td class="right bot"><a href="#Page_234">234</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Pyramidalis nasi</td>
+<td class="right bot"><a href="#Page_235">235</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Corrugator supercilii</td>
+<td class="right bot"><a href="#Page_235">235</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Zygomaticus major</td>
+<td class="right bot"><a href="#Page_235">235</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Zygomaticus minor</td>
+<td class="right bot"><a href="#Page_236">236</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Levator labii superioris proprius</td>
+<td class="right bot"><a href="#Page_237">237</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Levator labii superioris al&aelig;que nasi</td>
+<td class="right bot"><a href="#Page_238">238</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Transversus nasi</td>
+<td class="right bot"><a href="#Page_239">239</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Caninus</td>
+<td class="right bot"><a href="#Page_239">239</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Orbicularis oris</td>
+<td class="right bot"><a href="#Page_240">240</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Triangularis oris</td>
+<td class="right bot"><a href="#Page_240">240</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Quadratus menti</td>
+<td class="right bot"><a href="#Page_240">240</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Prominence of the chin</td>
+<td class="right bot"><a href="#Page_240">240</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Buccinator</td>
+<td class="right bot"><a href="#Page_241">241</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top padl2">Maxillo-labialis</td>
+<td class="right bot"><a href="#Page_242">242</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Zygomatico-auricularis</td>
+<td class="right bot"><a href="#Page_242">242</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Temporo-auricularis externus</td>
+<td class="right bot"><a href="#Page_243">243</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Scuto-auricularis externus</td>
+<td class="right bot"><a href="#Page_243">243</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Cervico-auricular muscles</td>
+<td class="right bot"><a href="#Page_243">243</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Cervico-auricularis superioris</td>
+<td class="right bot"><a href="#Page_244">244</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Cervico-auricularis medius</td>
+<td class="right bot"><a href="#Page_244">244</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Cervico-auricularis inferioris</td>
+<td class="right bot"><a href="#Page_244">244</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Parotido-auricularis</td>
+<td class="right bot"><a href="#Page_244">244</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Temporo-auricularis internus</td>
+<td class="right bot"><a href="#Page_244">244</a></td>
+</tr>
+
+<tr>
+<td colspan="3">&nbsp;</td>
+<td class="left top">Zygomatico-auricularis</td>
+<td class="right bot"><a href="#Page_245">245</a></td>
+</tr>
+
+<tr style="margin-top: 2em;">
+<td colspan="5" class="center" style="padding: 1em 0;">EPIDERMIC PRODUCTS OF THE TERMINAL
+EXTREMITIES OF THE FORE AND HIND LIMBS</td>
+</tr>
+
+<tr>
+<td colspan="4" class="left top">Claws</td>
+<td class="right bot"><a href="#Page_247">247</a></td>
+</tr>
+
+<tr>
+<td colspan="4" class="left top">Plantar tubercles</td>
+<td class="right bot"><a href="#Page_248">248</a></td>
+</tr>
+
+<tr>
+<td colspan="4" class="left top">Hoofs of the solipeds</td>
+<td class="right bot"><a href="#Page_250">250</a></td>
+</tr>
+
+<tr>
+<td colspan="4" class="left top">Hoofs of ox and pig</td>
+<td class="right bot"><a href="#Page_261">261</a></td>
+</tr>
+
+<tr>
+<td colspan="5" class="center"><hr class="c05" style="margin-top: .25em; margin-bottom: .25em;"/></td>
+</tr>
+
+<tr>
+<td colspan="4" class="left top">Proportions</td>
+<td class="right bot"><a href="#Page_262">262</a></td>
+</tr>
+
+<tr>
+<td colspan="4" class="left top">Proportions of head of horse</td>
+<td class="right bot"><a href="#Page_273">273</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">(front view)</td>
+<td class="right bot"><a href="#Page_276">276</a></td>
+</tr>
+
+<tr>
+<td colspan="4" class="left top">Paces of the horse<span class="pagenum"><a name="Page_314" id="Page_314">[314]</a></span></td>
+<td class="right bot"><a href="#Page_282">282</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Amble</td>
+<td class="right bot"><a href="#Page_293">293</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Trot</td>
+<td class="right bot"><a href="#Page_294">294</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Walk</td>
+<td class="right bot"><a href="#Page_296">296</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Gallop</td>
+<td class="right bot"><a href="#Page_300">300</a></td>
+</tr>
+
+<tr>
+<td>&nbsp;</td>
+<td colspan="3" class="left top">Leap</td>
+<td class="right bot"><a href="#Page_304">304</a></td>
+</tr>
+
+</table>
+
+<hr class="c25" />
+<h2>ERRATA</h2>
+
+<p>P. 105, <i>Articulations</i> of the Posterior Limbs.</p>
+
+<p>P. 107, Tibio-tarsal <i>Articulation</i>.</p>
+
+<p class="fsize125 center" style="margin-top: 2em; margin-bottom: 2em;">THE END</p>
+
+<p class="fsize80 center" style="margin-top: 2em; margin-bottom: 2em;"><span class="bt"><i>London:
+Bailli&egrave;re, Tindall and Cox, 8, Henrietta Street, Covent Garden, W.C.</i></span></p>
+
+<div class="bbox" style="padding: 1em; margin-left: 10%; margin-right: 10%;"><a name="TN" id="TN"></a>
+<h2>Transcriber&#8217;s Notes:</h2>
+<ul style="text-align: justify;">
+  <li>Footnotes have been moved to underneath the paragraph, table or illustration they refer to.</li>
+  <li>Illustrations have been moved so as to not disrupt the flow of the text. Page numbers in the List of Illustrations and in
+      references are therefore not always correct. The hyperlinks point directly to the illustrations, and page numbers in references to
+      illustrations have not been hyperlinked.</li>
+  <li>The Table of Contents and the Sectional Index are not complete and contain slightly different wording than the names of sections in
+      the text. This has been left as in the original work.</li>
+  <li>The Errata have already been changed in the text.</li>
+  <li>Terms such as natural size are not valid for this e-text.</li>
+  <li>Depending on the browser used an its setting, not all characters may be display correctly.</li>
+  <li>The author uses the terms chromophotograph and chronophotograph (and derivations of these words); these words have not been changed.
+      The correct term in these cases is chronophotograph.</li>
+  <li>Page 143, Fig. 69: atlas is mentioned twice (nrs. 12 and 13); only nr. 13 indicates the atlas.</li>
+  <li>The text used is that of the original work, including inconsistencies in spelling, hyphenation and lay-out, and differences between
+      main text, footnotes and captions, except when mentioned below.</li>
+  <li>Changes made to the text:
+  <ul style="text-align: justify;">
+      <li>Some minor obvious typographical errors have been corrected silently.</li>
+      <li>Periods have been removed from some section headings for consistency.</li>
+      <li>Page 2, footnote [2]: Mathias-Duval changed to Mathias Duval (full name: Mathias-Marie Duval).</li>
+      <li>Page 23: <i>see</i> replaced with see for consistency.</li>
+      <li>Page 44 (footnote): Edward Cuyer changed to &Eacute;douard Cuyer as elsewhere.</li>
+      <li>Page 53, sub-captions (2x): AA<sup>1</sup> changed to AA&#8242; as in drawing and text</li>
+      <li>Page 120, Fig. 63: 14&#8242; is malar bone, 14 is anterior orifice of the cavity of the nasal foss&aelig; (see previous
+          figures).</li>
+      <li>Page 140, Fig. 61: 0 changed to 20.</li>
+      <li>Page 216: tendo-Achilles changed to tendo-Achillis as elsewhere.</li>
+      <li>Page 234: Fig. 0, 92 changed to Fig. 90, 2.</li>
+      <li>Page 250, Fig. 95: nr. 2 added to drawing.</li>
+      <li>Page 269, last paragraph: one anchor to same footnote deleted.</li>
+      <li>Page 277, Fig. 98: epternal changed to external.</li>
+      <li>Page 325: L, D, L&#8217;, D&#8217; changed to L, D, L&#8242;, D&#8242;</li>
+      <li>Footnotes 13, 17: La Natura changed to La Nature</li>
+  </ul></li>
+</ul>
+</div>
+
+
+
+
+
+
+
+
+<pre>
+
+
+
+
+
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+</body>
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+The Project Gutenberg EBook of Artistic Anatomy of Animals, by Edouard Cuyer
+
+This eBook is for the use of anyone anywhere at no cost and with
+almost no restrictions whatsoever.  You may copy it, give it away or
+re-use it under the terms of the Project Gutenberg License included
+with this eBook or online at www.gutenberg.org
+
+
+Title: Artistic Anatomy of Animals
+
+Author: Edouard Cuyer
+
+Release Date: December 15, 2011 [EBook #38315]
+
+Language: English
+
+Character set encoding: ASCII
+
+*** START OF THIS PROJECT GUTENBERG EBOOK ARTISTIC ANATOMY OF ANIMALS ***
+
+
+
+
+Produced by Chris Curnow, Harry Lame and the Online
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+by The Internet Archive)
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+  +--------------------------------------------------------------------+
+  |                       TRANSCRIBER'S NOTES                          |
+  |                                                                    |
+  | Transcription used in this e-text:                                 |
+  |   Texts in italics in the original work are transcribed between    |
+  |   underscores, as in _text_.                                       |
+  |   Bold-face text in the original work has been transcribed between |
+  |   equal signs, as in =text=.                                       |
+  |   Small capitals have been transcribed as ALL CAPITALS.            |
+  |   The author sometimes uses a different typeface to describe a     |
+  |   shape, as the V in V-form. Where this different typeface is used,|
+  |   this has been transcribed as [V].                                |
+  |                                                                    |
+  | More Transcriber's Notes will be found at the end of this text.    |
+  +--------------------------------------------------------------------+
+
+
+
+
+  THE
+  ARTISTIC ANATOMY OF ANIMALS
+
+
+
+
+  ARTISTIC
+  ANATOMY
+  OF ANIMALS
+
+  BY EDOUARD CUYER, SUPPLEMENTARY
+  PROF OF ANATOMY AT THE SCHOOL OF
+  FINE ART PARIS, PROF OF ANATOMY
+  AT THE SCHOOL OF FINE ART ROUEN
+
+  TRANSLATED & EDITED BY
+  GEORGE HAYWOOD
+  LECTURER ON ANATOMY AT THE ROYAL
+  COLLEGE OF ART SOUTH KENSINGTON
+
+  [Illustration]
+
+  LONDON
+  BAILLIERE, TINDALL & COX
+  8 HENRIETTA ST COVENT GARDEN
+
+  ANNO DOMINI
+  MDCCCCV
+
+  ALL RIGHTS
+  RESVD
+
+
+
+
+PREFACE
+
+
+A few lines will suffice to explain why we have compiled the present
+volume, to what wants it responds, and what its sphere of usefulness may
+possibly embrace.
+
+In our teaching of plastic anatomy, especially at the Ecole des
+Beaux-Arts--where, for the past nine years, we have had the very great
+honour of supplementing the teaching of our distinguished master,
+Mathias Duval, after having been prosector for his course of lectures
+since 1881--it is our practice to give, as a complement to the study of
+human anatomy, a certain number of lessons on the anatomy of those
+animals which artists might be called on to represent.
+
+Now, we were given to understand that the subject treated in our
+lectures interested our hearers, so much so that we were not surprised
+to learn that a certain number repeatedly expressed a desire to see
+these lectures united in book form.
+
+To us this idea was not new; for many years the work in question had
+been in course of preparation, and we had collected materials for it,
+with the object of filling up a void of which the existence was to be
+regretted. But our many engagements prevented us from executing our
+project as early as we would have wished. It is this work which we
+publish to-day.
+
+[Illustration: FIG. I.--REPRODUCTION OF A SKETCH BY BARYE (COLLECTIONS
+OF THE ANATOMICAL MUSEUM OF THE ECOLE DES BEAUX-ARTS--HUGUIER MUSEUM).]
+
+Putting aside for a moment the wish expressed by our hearers, we feel
+ourselves in duty bound to inquire whether the utility of this
+publication is self-evident. Let it be clearly understood that we wish
+to express here our opinion on this subject, while putting aside every
+personal sentiment of an author.
+
+No one now disputes the value of anatomical studies made in view of
+carrying out the artistic representation of man. Nevertheless--for we
+must provide against all contingencies--the conviction on this subject
+may be more or less absolute; and yet it must possess this character in
+an intense degree in order that these studies may be profitable, and
+permit the attainment of the goal which is proposed in undertaking them.
+It is in this way that we ever strive to train the students whose
+studies we direct; not only to admit the value of these studies, but to
+be materially and deeply convinced of the fact without any restriction.
+Such is the sentiment which we endeavour to create and vigorously
+encourage. And we may be permitted to add that we have often been
+successful in this direction.
+
+Therefore it is that, at the beginning of our lectures, and in
+anticipation of possible objections, we are accustomed to take up the
+question of the utility of plastic anatomy. And in so doing, it is in
+order to combat at the outset the idea--as mischievous as it is
+false--which is sometimes imprudently enunciated, that the possession of
+scientific knowledge is likely to tarnish the purity and freshness of
+the impressions received by the artist, and to place shackles on the
+emotional sincerity of their representation.
+
+[Illustration: FIG. II.--REPRODUCTION OF A SKETCH OF BARYE (COLLECTIONS
+OF THE ANATOMICAL MUSEUM OF THE ECOLE DES BEAUX-ARTS--HUGUIER MUSEUM).]
+
+It is chiefly by employment of examples that we approach the subject.
+These strike the imagination of the student more forcibly, and the
+presentation of models of a certain choice, although rough in execution,
+is, in our opinion, preferable to considerations of an order possibly
+more exalted, but of a character less clearly practical. Let us, then,
+ask the question: Those artists whose eminence nobody would dare to
+question, did they study anatomy? If the answer be in the affirmative,
+we surely cannot permit ourselves to believe that we can dispense with a
+similar course. And, as proof of the studies of this class which the
+masters have made, we may cite Raphael, Michelangelo, and, above all,
+Leonardo da Vinci; and, of the moderns, Gericault. And we may more
+clearly define these proofs by an examination of the reproductions of
+their anatomical works, chosen from certain of their special
+writings.[1]
+
+  [1] Mathias Duval and A. Bical, 'L'anatomie des Maitres.' Thirty
+      plates reproduced from the originals of Leonardo da Vinci,
+      Michelangelo, Raphael, Gericault, etc., with letterpress and a
+      history of plastic anatomy, Paris, 1890.
+
+      The manuscripts of Leonardo da Vinci of the Royal Library,
+      Windsor, 'Anatomy, Foliae A.,' published by Theodore Sabachnikoff,
+      with a French translation, written and annotated by Giovanni
+      Piumati, with an introduction by Mathias Duval. Edouard Rouveyre,
+      publisher, Paris, 1898.
+
+      Mathias Duval and Edouard Cuyer, 'History of Plastic Anatomy: The
+      Masters, their Books, and Anatomical Figures' (Library of
+      Instruction of the School of Fine Arts), Paris, 1898.
+
+Accordingly, there is no scope for serious discussion, and it only
+remains for us to enunciate the opinion that it is necessary that we
+should imitate those masters, and, with a sense of respectful
+discipline, follow their example.
+
+Here, with regard to the anatomy of animals, we pursue the same method,
+and the example chosen shall be that of Barye. His talent is too far
+above all criticism to allow that this example should be refused. The
+admiration which the works of this great artist elicit is too
+wide-spread for us to remain uninfluenced by the lessons furnished by
+his studies. It is sufficient to see the sketches relating to these
+studies, and his admirable casts from nature which form part of the
+anatomical museum of the Ecole des Beaux-Arts, to be convinced that the
+artistic temperament, of which Barye was one of the most brilliant
+examples, has nothing to lose by its association with researches the
+precision of which might seem likely to check its complete expansion.
+
+[Illustration: FIG. III.--REPRODUCTION OF A SKETCH OF BARYE (COLLECTIONS
+OF THE ANATOMICAL MUSEUM OF THE ECOLE DES BEAUX-ARTS--HUGUIER MUSEUM).]
+
+In those sketches we find proofs of observation so scrupulous that we
+cannot restrain our admiration for the man whose ardent imagination
+was voluntarily subjected to the toil of study so profound.
+
+If the example of Barye, with whom we associate the names of other great
+modern painters of animals, can determine the conviction which we seek
+to produce, we shall be sincerely glad. To contribute to the propagation
+of useful ideas, and to see them accepted, gives a feeling of
+satisfaction far too legitimate for us to hesitate to say what we should
+feel if our hope be realized in this instance.
+
+EDOUARD CUYER.
+
+[Illustration: FIG. IV.--REPRODUCTION OF A SKETCH OF BARYE (COLLECTIONS
+OF ANATOMICAL MUSEUM OF THE SCHOOL OF FINE ARTS--HUGUIER MUSEUM).]
+
+
+
+
+CONTENTS
+
+
+  INTRODUCTION
+
+                                                                   PAGE
+
+  GENERALITIES OF COMPARATIVE ANATOMY                                 1
+
+
+  CHAPTER I
+
+  OSTEOLOGY AND ARTHROLOGY:
+
+  THE TRUNK                                                           4
+  THE POSTERIOR LIMBS                                                78
+  THE POSTERIOR LIMBS IN SOME ANIMALS                                90
+  THE SKULL OF BIRDS                                                127
+
+
+  CHAPTER II
+
+  MYOLOGY:
+
+  THE MUSCLES OF THE TRUNK                                          131
+  MUSCLES OF THE ANTERIOR LIMBS                                     162
+  MUSCLES OF THE POSTERIOR LIMBS                                    200
+  MUSCLES OF THE HEAD                                               232
+
+
+  CHAPTER III
+
+  EPIDERMIC PRODUCTS OF THE EXTREMITIES OF THE FORE AND HIND LIMBS  247
+
+
+  CHAPTER IV
+
+  PROPORTIONS
+
+  PROPORTIONS OF THE HEAD OF THE HORSE                              273
+
+
+  CHAPTER V
+
+  THE PACES OF THE HORSE                                            282
+
+
+
+
+LIST OF ILLUSTRATIONS
+
+
+  FIG.                                                             PAGE
+
+    1. A HUMAN SKELETON IN THE ATTITUDE OF A QUADRUPED, TO GIVE A
+       GENERAL IDEA OF THE POSITION OF THE BONES IN OTHER
+       VERTEBRATES                                                    5
+    2. SIZE OF THE ATLAS COMPARED WITH THE TRANSVERSE DIMENSIONS OF
+       THE CORRESPONDING PARTS OF THE SKULL IN MAN                    7
+    3. SIZE OF THE ATLAS COMPARED WITH THE TRANSVERSE DIMENSIONS OF
+       THE CORRESPONDING REGIONS OF THE SKULL IN A DOG                8
+    4. LUMBAR VERTEBRAE OF A QUADRUPED (THE HORSE): SUPERIOR SURFACE   9
+    5. A TRANSVERSE SECTION OF THE THORAX OF A MAN PLACED
+       VERTICALLY--THAT IS TO SAY, IN THE DIRECTION WHICH IT WOULD
+       ASSUME IN A MAN PLACED IN THE ATTITUDE OF A QUADRUPED (A
+       DIAGRAMMATIC FIGURE)                                          13
+    6. A VERTICAL SECTION OF THE THORAX OF A QUADRUPED
+       (DIAGRAMMATIC)                                                14
+    7. STERNUM OF A BIRD (THE COCK): LEFT SIDE, EXTERNAL SURFACE     17
+    8. ANTERIOR LIMB OF THE BAT: LEFT SIDE, ANTERIOR SURFACE         20
+    9. ANTERIOR LIMB OF THE SEAL: LEFT SIDE, EXTERNAL SURFACE        21
+   10. SITUATION AND DIRECTION OF THE SCAPULA IN THE HUMAN BEING,
+       THE TRUNK BEING HORIZONTAL, AS IN QUADRUPEDS. VERTICAL AND
+       TRANSVERSE SECTION OF THE THORAX (DIAGRAMMATIC FIGURE)        22
+   11. POSITION AND DIRECTION OF THE SCAPULA IN QUADRUPEDS.
+       VERTICAL AND TRANSVERSE SECTION OF THE THORAX (DIAGRAMMATIC
+       FIGURE)                                                       22
+   12. LEFT SCAPULA OF THE HUMAN BEING, POSTERIOR SURFACE, PLACED
+       IN THE POSITION WHICH IT WOULD OCCUPY IN THE SKELETON OF A
+       QUADRUPED                                                     23
+   13. LEFT SCAPULA OF A HORSE: EXTERNAL SURFACE                     23
+   14. VERTICAL AND TRANSVERSE SECTION, AT THE SITE OF THE
+       SHOULDERS, OF THE THORAX OF THE HORSE (DIAGRAMMATIC FIGURE)   24
+   15. VERTICAL AND TRANSVERSE SECTION, AT THE PLANE OF THE
+       SHOULDERS, OF THE THORAX OF THE DOG (DIAGRAMMATIC FIGURE)     24
+   16. LEFT CLAVICLE OF THE CAT: SUPERIOR SURFACE (NATURAL SIZE)     26
+   17. CLAVICLE OF THE DOG (NATURAL SIZE)                            26
+   18. SKELETON OF THE SHOULDER OF A BIRD (VULTURE): ANTERO-
+       EXTERNAL VIEW OF THE LEFT SIDE                                27
+   19. INFERIOR EXTREMITY OF THE LEFT HUMERUS OF A FELIDAE (LION)     31
+   20. INFERIOR EXTREMITY OF THE LEFT HUMAN HUMERUS, SHOWING THE
+       PRESENCE OF A SUPRATROCHLEAR PROCESS                          31
+   21. SKELETON OF A BIRD (VULTURE): LEFT SURFACE                    33
+   22. THE HUMAN HAND RESTING FOR ITS WHOLE EXTENT ON ITS PALMAR
+       SURFACE: LEFT SIDE, EXTERNAL SURFACE                          35
+   23. THE HUMAN HAND RESTING ON ITS PHALANGES: LEFT SIDE, EXTERNAL
+       SURFACE                                                       36
+   24. THE HUMAN HAND RESTING ON THE TIPS OF SOME OF ITS THIRD
+       PHALANGES: LEFT SIDE, EXTERNAL VIEW                           36
+   25. SUPERIOR EXTREMITY OF THE BONES OF THE HUMAN FOREARM: LEFT
+       SIDE, SUPERIOR SURFACE                                        39
+   26. SUPERIOR EXTREMITY OF THE BONES OF THE FOREARM OF A DOG:
+       LEFT LIMB, SUPERIOR SURFACE                                   39
+   27. SUPERIOR EXTREMITY OF THE BONES OF THE FOREARM OF THE HORSE:
+       LEFT LIMB, SUPERIOR SURFACE                                   40
+   28. INFERIOR EXTREMITY OF THE BONES OF THE FOREARM OF A MAN:
+       LEFT SIDE, POSTERIOR SURFACE, POSITION OF SUPINATION          41
+   29. INFERIOR EXTREMITY OF THE BONES OF THE FOREARM OF A DOG:
+       LEFT SIDE, ANTERIOR SURFACE, NORMAL POSITION--THAT IS, THE
+       POSITION OF PRONATION                                         41
+   30. INFERIOR EXTREMITY OF THE BONE OF THE FOREARM OF THE HORSE:
+       LEFT SIDE, ANTERIOR SURFACE                                   42
+   31. SKELETON OF THE SUPERIOR LIMB OF A BIRD (VULTURE): LEFT
+       SIDE, EXTERNAL SURFACE                                        47
+   32. SUPERIOR LIMB OF THE HUMAN BEING, THE DIFFERENT SEGMENTS
+       BEING PLACED IN THE ATTITUDE WHICH THE CORRESPONDING PARTS
+       OCCUPY IN BIRDS: LEFT SIDE, EXTERNAL SURFACE                  48
+   33. SKELETON OF THE BEAR: LEFT LATERAL SURFACE                    50
+   34. SKELETON OF THE DOG: LEFT LATERAL SURFACE                     52
+   35. SCAPULA OF THE DOG: LEFT SIDE, EXTERNAL SURFACE               53
+   36. LEFT SCAPULA OF THE CAT: EXTERNAL SURFACE                     53
+   37. SKELETON OF THE FINGER OF A FELIDE (LION): LEFT SIDE,
+       INTERNAL SURFACE                                              57
+   38. SKELETON OF THE PIG: LEFT LATERAL SURFACE                     58
+   39. SKELETON OF THE OX: LEFT LATERAL SURFACE                      61
+   40. SKELETON OF THE HORSE: LEFT LATERAL SURFACE                   64
+   41. FLEXION OF THE HUMERUS: RIGHT ANTERIOR LIMB OF THE HORSE,
+       EXTERNAL SURFACE (AFTER A CHROMOPHOTOGRAPHIC STUDY BY
+       PROFESSOR MAREY)                                              74
+   42. EXTENSION OF THE HUMERUS: RIGHT ANTERIOR LIMB OF THE HORSE,
+       EXTERNAL SURFACE (AFTER A CHROMOPHOTOGRAPHIC STUDY BY
+       PROFESSOR MAREY)                                              74
+   43. THE LEFT ILIAC BONE OF THE HUMAN BEING: EXTERNAL SURFACE,
+       PLACED IN THE POSITION WHICH IT WOULD OCCUPY IN THE SKELETON
+       OF A QUADRUPED                                                79
+   44. LEFT ILIAC BONE OF A QUADRUPED (HORSE): EXTERNAL SURFACE      79
+   45. PUBIC REGION OF THE PELVIS OF A MARSUPIAL (PHALANGER, FOX)    81
+   46. PELVIS OF A BIRD (THE COCK): EXTERNAL SURFACE, LEFT SIDE      82
+   47. POSTERIOR LIMB OF THE HORSE PLACED IN THE POSITION WHICH IT
+       SHOULD OCCUPY IF THE ANIMAL WERE A PLANTIGRADE: LEFT LIMB,
+       EXTERNAL SURFACE                                              89
+   48. SKELETON OF THE FOOT OF A BIRD (THE COCK): LEFT SIDE,
+       EXTERNAL SURFACE                                              90
+   49. PELVIS OF THE DOG, SEEN FROM ABOVE                            91
+   50. PELVIS OF A FELIDE (LION), VIEWED FROM ABOVE                  92
+   51. PELVIS OF THE OX: SUPERIOR SURFACE                            95
+   52. TARSUS OF THE OX: POSTERIOR LEFT LIMB, ANTERO-EXTERNAL
+       SURFACE                                                       97
+   53. PELVIS OF THE HORSE: SUPERIOR SURFACE                        101
+   54. TARSUS OF THE HORSE: LEFT POSTERIOR LIMB, ANTERIOR SURFACE   104
+   55. EXTENSION OF THE LEG: RIGHT POSTERIOR LIMB OF THE HORSE,
+       EXTERNAL SURFACE (AFTER A CHRONOGRAPHIC STUDY BY PROFESSOR
+       MAREY)                                                       107
+   56. HUMAN SKULL: MEASURE OF THE FACIAL ANGLE BY THE METHOD OF
+       CAMPER. ANGLE BAC = 80 deg.                                      110
+   57. SKULL OF THE HORSE: MEASURE OF THE FACIAL ANGLE BY THE
+       METHOD OF CAMPER. ANGLE BAC = 13 deg.                            110
+   58. SKULL OF ONE OF THE FELIDAE (JAGUAR): LEFT LATERAL ASPECT     113
+   59. SKULL OF THE LION: LEFT LATERAL ASPECT                       113
+   60. SKULL OF THE DOG: LEFT LATERAL ASPECT                        115
+   61. SKULL OF THE PIG: LEFT LATERAL ASPECT                        117
+   62. SKULL OF THE OX: LEFT LATERAL ASPECT                         119
+   63. SKULL OF THE HORSE: LEFT LATERAL ASPECT                      121
+   64. SKULL OF THE HARE: LEFT LATERAL ASPECT                       123
+   65. SKULL OF THE COCK: LEFT LATERAL SURFACE                      128
+   66. MYOLOGY OF THE HORSE: ANTERIOR ASPECT OF THE TRUNK           132
+   67. MYOLOGY OF THE HORSE: INFERIOR ASPECT OF THE TRUNK           135
+   68. MYOLOGY OF THE DOG: SUPERFICIAL LAYER OF MUSCLES             141
+   69. MYOLOGY OF THE OX: SUPERFICIAL LAYER OF MUSCLES              143
+   70. MYOLOGY OF THE HORSE: SUPERFICIAL LAYER OF MUSCLES           146
+   71. MYOLOGY OF THE HORSE: PANNICULUS MUSCLE OF THE TRUNK         148
+   72. MYOLOGY OF THE HORSE--SHOULDER AND ARM: LEFT SIDE, EXTERNAL
+       SURFACE                                                      166
+   73. MYOLOGY OF THE DOG: LEFT ANTERIOR LIMB, EXTERNAL ASPECT      178
+   74. MYOLOGY OF THE OX: LEFT ANTERIOR LIMB, EXTERNAL ASPECT       180
+   75. MYOLOGY OF THE HORSE: LEFT ANTERIOR LIMB, EXTERNAL ASPECT    182
+   76. MYOLOGY OF THE DOG: LEFT ANTERIOR LIMB, INTERNAL ASPECT      190
+   77. MYOLOGY OF THE HORSE: ANTERIOR LIMB, LEFT SIDE, INTERNAL
+       ASPECT                                                       192
+   78. LEFT ANTERIOR LIMB OF THE HORSE: INTERNAL ASPECT             194
+   79. LEFT ANTERIOR LIMB OF THE HORSE: EXTERNAL ASPECT             196
+   80. LEFT ANTERIOR LIMB OF THE HORSE: EXTERNAL ASPECT             196
+   81. DIAGRAM OF THE POSTERIOR PART OF A TRANSVERSE SECTION
+       PASSING THROUGH THE MIDDLE OF THE LEFT FORE-LIMB OF THE DOG:
+       SURFACE OF THE INFERIOR SEGMENT OF THE SECTION               198
+   82. DIAGRAM OF A HORIZONTAL SECTION OF THE MIDDLE OF THE FOREARM
+       OF THE LEFT LEG OF THE HORSE: SURFACE OF THE INTERIOR
+       SEGMENT OF THE SECTION                                       198
+   83. MYOLOGY OF THE HORSE: THE ANTERIOR TIBIAL MUSCLE (FLEXOR OF
+       THE METATARSUS), LEFT LEG, ANTERIOR VIEW                     214
+   84. MYOLOGY OF THE DOG: LEFT HIND-LIMB, EXTERNAL ASPECT          216
+   85. MYOLOGY OF THE OX: LEFT LEG, EXTERNAL ASPECT                 218
+   86. MYOLOGY OF THE HORSE: LEFT HIND-LIMB, EXTERNAL ASPECT        220
+   87. MYOLOGY OF THE DOG: LEFT HIND-LIMB, INTERNAL ASPECT          222
+   88. MYOLOGY OF THE HORSE: LEFT HIND-LEG, INTERNAL ASPECT         223
+   89. MYOLOGY OF THE DOG: MASTICATORY MUSCLES (A DEEPER DISSECTION
+       THAN THAT SHOWN IN FIG. 90)                                  233
+   90. MYOLOGY OF THE DOG: MUSCLES OF THE HEAD                      235
+   91. MYOLOGY OF THE OX: MUSCLES OF THE HEAD                       237
+   92. MYOLOGY OF THE HORSE: MUSCLES OF THE HEAD                    239
+   93. CLAW OF THE DOG: INFERIOR SURFACE                            249
+   94. LEFT HAND OF THE DOG: INFERIOR SURFACE, PLANTAR TUBERCLES    249
+   95. VERTICAL ANTERO-POSTERIOR SECTION OF THE FOOT OF A HORSE     250
+   96. THIRD PHALANX OF THE HORSE: LEFT ANTERIOR LIMB, EXTERNAL
+       SURFACE                                                      251
+   97. LEFT ANTERIOR FOOT OF THE HORSE: ANTERIOR ASPECT             253
+   98. LEFT ANTERIOR FOOT OF THE HORSE: EXTERNAL ASPECT             254
+   99. VERTICAL AND TRANSVERSE SECTION OF A LEFT HUMAN FOOT:
+       OUTLINE OF THE SURFACE OF THE POSTERIOR SEGMENT OF THIS
+       SECTION (DIAGRAMMATIC FIGURE)                                255
+  100. INFERIOR SURFACE OF A FORE-HOOF OF THE HORSE: LEFT SIDE      256
+  101. THIRD PHALANX OF THE HORSE: LEFT ANTERIOR LIMB, INFERIOR
+       VIEW                                                         257
+  102. THIRD PHALANX OF THE HORSE: LEFT POSTERIOR LIMB, INFERIOR
+       VIEW                                                         257
+  103. INFERIOR SURFACE OF A HIND-HOOF OF A HORSE: LEFT SIDE        258
+  104. LEFT POSTERIOR FOOT OF A HORSE: EXTERNAL ASPECT              259
+  105. FOOT OF THE OX: LEFT SIDE, ANTERO-EXTERNAL VIEW              260
+  106. THE PROPORTIONS OF THE HORSE (AFTER BOURGELAT)               265
+  107. PROPORTIONS OF THE HORSE (AFTER COLONEL DUHOUSSET)           270
+  108. PROPORTIONS OF THE HEAD OF THE HORSE, VIEWED IN PROFILE
+       (AFTER COLONEL DUHOUSSET)                                    274
+  109. THE SAME DESIGN AS THAT OF FIG. 108, ON WHICH WE HAVE
+       INDICATED, BY SIMILAR LINES, THE PRINCIPAL CORRESPONDING
+       MEASUREMENTS                                                 275
+  110. PROPORTIONS OF THE HEAD OF THE HORSE, SEEN FROM THE FRONT
+       (AFTER COLONEL DUHOUSSET)                                    276
+  111. THE SAME FIGURE AS FIG. 110, ON WHICH WE HAVE MARKED, BY
+       SIMILAR LINES, THE PRINCIPAL MEASUREMENTS WHICH CORRESPOND
+       THERETO                                                      277
+  112. HORSE OF WHICH THE LENGTH CONTAINS MORE THAN TWO AND A HALF
+       TIMES THAT OF THE HEAD, AND OF WHICH THIS DIMENSION (A, B)
+       EXCEEDS THE HEIGHT                                           279
+  113. HORSE OF WHICH THE LENGTH CONTAINS MORE THAN TWO AND A HALF
+       TIMES THAT OF THE HEAD, AND OF WHICH THIS DIMENSION (A, B)
+       EXCEEDS THE HEIGHT                                           280
+  114. HORSE OF WHICH THE LENGTH CONTAINS MORE THAN TWO AND A HALF
+       TIMES THAT OF THE HEAD, AND OF WHICH THIS DIMENSION (A, B)
+       IS INFERIOR TO THE HEIGHT                                    281
+  115. EXPERIMENTAL SHOES, INTENDED TO RECORD THE PRESSURE OF THE
+       FOOT ON THE GROUND                                           284
+  116. RUNNER FURNISHED WITH THE EXPLORATORY AND REGISTERING
+       APPARATUS OF THE VARIOUS PACES                               285
+  117. TRACING OF THE RUNNING OF A MAN (AFTER PROFESSOR MAREY)      286
+  118. NOTATION OF A TRACING OF THE RUNNING OF A MAN (AFTER
+       PROFESSOR MAREY)                                             287
+  119. NOTATION OF VARIOUS MODES OF PROGRESSION OF A MAN (AFTER
+       PROFESSOR MAREY)                                             287
+  120. SWING OF THE RAISED ANTERIOR LIMB (AFTER G. COLIN)           289
+  121. SWING OF THE ANTERIOR LIMB ON THE POINT OF PRESSURE (AFTER
+       G. COLIN)                                                    290
+  122. POSTERIOR LIMB, GIVING THE IMPULSE (AFTER G. COLIN)          291
+  123. NOTATION OF THE AMBLING GAIT IN THE HORSE (AFTER PROFESSOR
+       MAREY)                                                       292
+  124. THE AMBLE: RIGHT LATERAL PRESSURE                            293
+  125. NOTATION OF THE GAIT OF THE TROT IN A HORSE (AFTER PROFESSOR
+       MAREY)                                                       294
+  126. THE TROT: RIGHT DIAGONAL PRESSURE                            295
+  127. THE TROT: TIME OF SUSPENSION                                 295
+  128. NOTATION OF THE PACE OF STEPPING IN THE HORSE (AFTER
+       PROFESSOR MAREY)                                             296
+  129. THE STEP: RIGHT LATERAL PRESSURE                             297
+  130. THE STEP: RIGHT DIAGONAL PRESSURE                            297
+  131. THE GALLOP: FIRST PERIOD                                     298
+  132. THE GALLOP: SECOND PERIOD                                    298
+  133. THE GALLOP: THIRD PERIOD                                     299
+  134. THE GALLOP: TIME OF SUSPENSION                               299
+  135. NOTATION OF THE GALLOP DIVIDED INTO THREE PERIODS OF TIME
+       (AFTER PROFESSOR MAREY)                                      300
+  136. NOTATION OF THE GALLOP OF FOUR PERIODS IN THE HORSE (AFTER
+       PROFESSOR MAREY)                                             300
+  137. LEAP OF THE HARE (AFTER G. COLIN)                            301
+  138. THE LEAP                                                     302
+  139. THE LEAP                                                     302
+  140. THE LEAP                                                     303
+  141. THE LEAP                                                     303
+  142. THE LEAP                                                     305
+  143. THE LEAP                                                     305
+
+
+
+
+THE ARTISTIC ANATOMY OF ANIMALS
+
+
+
+
+INTRODUCTION
+
+GENERALITIES OF COMPARATIVE ANATOMY
+
+
+Of the animals by which we are surrounded, there are some which,
+occupying a place in our lives by reason of their natural endowments,
+are frequently represented in the works of artists--either as
+accompanying man in his work or in his amusements, or as intended to
+occupy the whole interest of the composition.
+
+The necessity of knowing, from an artistic point of view, the structure
+of the human body makes clear the importance we attach, from the same
+point of view, to the study of the anatomy of animals--that is, the
+study of comparative anatomy. The name employed to designate this branch
+of anatomy shows that the object of this science is the study of the
+relative position and form which each region presents in all organized
+beings, taking for comparison the corresponding regions in man. The head
+in animals compared with the human head; the trunk and limbs compared to
+the trunk and limbs of the human being--this is the analysis we
+undertake, and the plan of the subject we are about to commence.
+
+Our intention being, as we have just said, the comparison of the
+structure of animals with that of man, should we describe the anatomy of
+the human being in the pages which follow? We do not think so. Plastic
+human anatomy having been previously studied in special works,[2] we
+take it for granted that these have been studied before undertaking the
+subject of comparative anatomy. We will therefore not occupy time with
+the elementary facts relative to the skeleton and the superficial layer
+of muscles. We will not dilate on the division of the bones into long,
+short, large, single, paired, etc. All these preliminary elements we
+shall suppose to have been already studied.
+
+  [2] Mathias Duval, 'Precis of Anatomy for the Use of Artists': Paris,
+      1881. 'Artistic Anatomy of the Human Body,' third edition, plates
+      by Dr. Fau, text with figures by Edouard Cuyer: Paris, 1896.
+      'Artistic Anatomy of Man,' by J. C. L. Sparkes, second edition,
+      text with 50 plates: Bailliere, Tindall and Cox, London, 1900.
+
+This being granted, it is, nevertheless, necessary to take a rapid
+bird's-eye view of organized beings, and to recall the terms used in
+their classification.
+
+Animals are primarily classed in great divisions, based on the general
+characters which differentiate them most. These divisions, or
+_branches_, allow of their being so grouped that in each of them we find
+united the individuals whose general structure is uniform; and under the
+name of vertebrates are included man and the animals with which our
+studies will be occupied. The vertebrates, as the name indicates, are
+recognised by the presence of an interior skeleton formed by a central
+axis, the vertebral column, round which the other parts of the skeleton
+are arranged.
+
+The vertebrate branch is divided into classes: fishes, amphibians or
+batrachians, reptiles, birds, and mammals.
+
+The mammals--from the Latin _mamma_, a breast--are characterized by the
+presence of breasts designed for the alimentation of their young. Their
+bodies are covered with hair, hence the name _piliferes_ proposed by
+Blainville; and, notwithstanding that in some individuals the hairs are
+few, the character is sufficient to distinguish them from all other
+vertebrates.
+
+We find united in this class animals which, at first, seem out of place,
+such as the whale and the bat; and, from their external appearance
+alone, the former would appear to belong to the fishes, and the latter
+to birds. Yet, on studying their structure, we find that, not only do
+these animals merit a place in the class which they occupy, because they
+possess the distinctive characters of mammals; but, still further, their
+internal structure is analogous to that of man and of the other
+individuals of this class.
+
+Notwithstanding this similarity of structure, the whale is not without
+some points of difference from its neighbours the horse and the dog;
+therefore, in order to place each of these animals in a position
+suitable to it, mammals are divided into secondary groups called
+_orders_. The first of these orders includes, under the name _primates_,
+man and apes. The latter contain animals which approach birds in certain
+characters of their organism, forming a link between the latter and
+mammals.
+
+We find, in studying the regions of the body in some of the vertebrates,
+that, while they present differences from the corresponding regions of
+the human body, they also offer most striking analogies. We can, for
+example, recognise the upper limb of man in the anterior one of
+quadrupeds, in the wing of the bat, in the paddle of the seal, etc. It
+is, so to speak, those variations of a great plan which give such a
+charm to the study of comparative anatomy.
+
+The division of classes into orders, which we have just mentioned,
+being still too general, it was found necessary to establish
+subdivisions--more and more specialized--to which the names _families_,
+_genera_, _species_, and _varieties_ were given.
+
+
+
+
+CHAPTER I
+
+OSTEOLOGY AND ARTHROLOGY
+
+
+THE TRUNK
+
+The Vertebral Column
+
+We commence the study of the skeleton with a description of the trunk.
+
+The trunk being, in quadrupeds, horizontal in direction (Fig. 1), the
+two regions of which it consists occupy, for this reason, the following
+positions: the thorax occupies the anterior part, the abdomen is placed
+behind it; the vertebral column is horizontal, and is situated at the
+superior aspect of the trunk; it projects beyond the latter: anteriorly,
+to articulate with the skull; and, posteriorly, to form the skeleton of
+the tail, or caudal appendix.
+
+The number of the vertebrae is not the same in all mammalia. Of the
+several regions of the vertebral column, the cervical shows the greatest
+uniformity in the number of the vertebrae of which it consists, with but
+two exceptions (eight or nine in the three-toed sloth, and six in the
+manatee); we always find seven cervical vertebrae, whatever the length of
+the neck of the animal. There are no more than seven vertebrae in the
+long neck of the giraffe, but they are very long ones; and not less than
+seven in the very short neck of the dolphin, in which they are reduced
+to mere plates of bone not thicker than sheets of cardboard. If the
+cervical region presents uniformity in the number of its bones, it is
+not so with the other regions of the column.
+
+The following table shows their classification in some animals:
+
+VERTEBRAE.
+
+  +------------+-----------+---------+---------+
+  |            | Cervical. | Dorsal. | Lumbar. |
+  +------------+-----------+---------+---------+
+  | Bear       |    7      |    14   |    6    |
+  | Dog        |    7      |    13   |    7    |
+  | Cat        |    7      |    13   |    7    |
+  | Rabbit     |    7      |    12   |    7    |
+  | Pig        |    7      |    14   |  6 or 7 |
+  | Horse      |    7      |    18   |  6 or 5 |
+  | Ass        |    7      |    18   |    5    |
+  | Camel      |    7      |    12   |    7    |
+  | Giraffe    |    7      |    14   |    5    |
+  | Ox         |    7      |    13   |    6    |
+  | Sheep      |    7      |    13   |    6    |
+  +------------+-----------+---------+---------+
+
+[Illustration: FIG. 1.--A HUMAN SKELETON IN THE ATTITUDE OF A QUADRUPED.
+TO GIVE A GENERAL IDEA OF THE POSITION OF THE BONES IN OTHER
+VERTEBRATES.]
+
+It is worthy of notice that in birds the number of the cervical vertebrae
+is not constant, as in mammals; they are more numerous than the dorsal.
+These latter are almost always joined to one another by a fusion of
+their spinous processes; the two or three last vertebrae are similarly
+united to the iliac bones, between which they are fixed. The dorsal
+vertebrae thus form one piece, which gives solidity to the trunk, and
+provides a base of support to the wings, for the movements of flying.
+There are, so to speak, no lumbar vertebrae, the bones of that region,
+which cannot be differentiated from the sacrum, having coalesced with
+the bones of the pelvis.
+
+VERTEBRAE.
+
+  +------------------+-----------+---------+
+  |                  | Cervical. | Dorsal. |
+  +------------------+-----------+---------+
+  | Vulture          |    15     |    7    |
+  | Eagle            |    13     |    9    |
+  | Cock             |    14     |    7    |
+  | Ostrich          |    18     |    9    |
+  | Swan             |    23     |   10    |
+  | Goose            |    18     |    9    |
+  | Duck             |    15     |    9    |
+  +------------------+-----------+---------+
+
+In reptiles, the relation between the number of the cervical vertebrae
+and that of the dorsal is very variable; some serpents are devoid of
+cervical vertebrae, having only dorsal ones--that is, vertebrae carrying
+well-developed ribs.
+
+VERTEBRAE.
+
+  +-------------------+-----------+---------+---------+
+  |                   | Cervical. | Dorsal. | Lumbar. |
+  +-------------------+-----------+---------+---------+
+  | Crocodile         |    7      |    14   |    3    |
+  | Caiman            |    7      |    12   |    5    |
+  | Boa               |    3      |   248   |    0    |
+  | Python            |    0      |   320   |    0    |
+  | Viper             |    2      |   145   |    0    |
+  +-------------------+-----------+---------+---------+
+
+Regarding the direction of the vertebral column in animals, in which the
+trunk is not vertical, it is evident that the spinous processes point
+upward, and that in comparing them with those of man they must be
+arranged so that the superior surface of the human vertebra will
+correspond to the anterior surface of that of the quadruped. Of the
+cervical vertebrae, the atlas and axis call for special notice. Apropos
+of the atlas, we find that it, in the human being, is narrower than the
+corresponding parts of the skull, and is therefore hidden under the base
+of the cranium (Fig. 2); in quadrupeds its width is equal to that of the
+skull, and sometimes exceeds, because of the great development of its
+wing-shaped transverse processes, that of the neighbouring parts of the
+head (Fig. 3). On this account those transverse processes often project
+under the skin of the lateral surfaces of the upper part of the neck.
+
+[Illustration: FIG. 2.--SIZE OF THE ATLAS COMPARED WITH THE TRANSVERSE
+DIMENSIONS OF THE CORRESPONDING PARTS OF THE SKULL IN MAN.
+
+1, Atlas; 2, mastoid process; 3, external occipital protuberance; 4,
+inferior maxilla.]
+
+The axis is furnished on its anterior surface with the odontoid process,
+which articulates with the anterior (or inferior) arch of the atlas,
+according to the direction of the neck. The spinous process, flattened
+from without inwards, is more or less pointed; it is elongated from
+before backwards, so as partly to overlap the atlas and the third
+cervical vertebra.
+
+We find that this process overlaps less and less the neighbouring
+vertebrae when we examine in succession the bear, the cat, the dog, the
+ox, and the horse. With regard to the other vertebrae of this region,
+they diminish in width from the second to the seventh; and, in some
+animals, the anterior surface of the body presents a tubercle which
+articulates with a cavity hollowed in the posterior surface of that of
+the vertebra before it; this feature dwindles away in the dorsal and
+lumbar regions.
+
+The spinous process, slightly developed in the third cervical vertebra,
+gradually increases in size to the seventh, the spinous process of
+which, long and pointed, well deserves the name of _the prominent_ which
+is bestowed on it; but it should not be forgotten that the spinous
+process of the axis is equally developed.
+
+[Illustration: FIG. 3.--SIZE OF THE ATLAS COMPARED WITH THE TRANSVERSE
+DIMENSIONS OF THE CORRESPONDING REGIONS OF THE SKULL IN A DOG.
+
+1, Atlas; 2, zygomatic arch; 3, external occipital protuberance; 4,
+inferior maxilla.]
+
+On the inferior surface of the body of each of the vertebrae is found a
+prominent crest, especially well marked at the posterior part; this
+crest is but slightly developed in the bear and in the cat tribe, and is
+not found in swine.
+
+The transverse processes of the cervical vertebrae, from their relation
+to the trachea, are known as the _tracheal processes_.
+
+The most marked characteristic of the dorsal vertebrae is furnished by
+the spinous processes. They are long and narrow. As a rule, the spinous
+processes of the foremost dorsal vertebrae are the most developed and
+are directed obliquely upwards and backwards. As we approach the last
+vertebrae of this region, the processes become shorter and tend to become
+vertical, and the last ones are even, in some cases, directed upwards
+and forwards; this disposition is well marked in the dog and the cat. In
+the cetaceans, on the contrary, the length of the spinous processes
+increases from the first to the last.
+
+[Illustration: FIG. 4.--LUMBAR VERTEBRAE OF A QUADRUPED (THE HORSE):
+SUPERIOR SURFACE.
+
+1, Spinous process; 2, anterior articular process and transverse process
+of the first lumbar vertebra of the left side; 3, costiform process.]
+
+In the horse the spinous processes of the first dorsal vertebrae produce
+the prominence at the anterior limit of the trunk, where the mane ends,
+which is known as the _withers_.
+
+The lumbar vertebrae are thicker than the preceding; they are known by
+their short and latterly-flattened spinous processes, and still more
+readily by their transverse processes, which, as they are evidently
+atrophied ribs, it is more accurate to denominate costiform processes
+(Fig. 4). These are long, flattened from above downwards, and directed
+outwards and forwards.
+
+The true transverse processes are represented by tubercles situated on
+the superior borders of the articular processes of each of the vertebrae
+of the lumbar region. Apropos of these different osseous processes, we
+are reminded that they are also present in the human skeleton.
+
+In the horse the costiform processes of the fifth and sixth lumbar
+vertebrae articulate, and are sometimes ankylosed, one with the other;
+the terminal ones articulate with the base of the sacrum. Sometimes the
+processes of the fourth and fifth are thus related; this is the case in
+the figure (4) given; here the costiform processes of the fourth and
+fifth vertebrae articulate, and the two terminal ones have coalesced.
+
+In the ox, the same processes are more developed than in the horse;
+their summits elevating the skin, produce, especially in animals which
+have not much flesh, prominences which limit the flanks in the superior
+aspect. The costiform processes of the last lumbar vertebrae are separate
+from each other; those of the latter are not in contact with the sacrum.
+
+=The Sacrum.=[3]--This bone, single and median, is formed by the mutual
+coalescence of several vertebrae, which vary in number according to the
+species observed.
+
+  [3] In human anatomy, the sacrum and the coccyx are studied as part of
+      the pelvis; we, therefore, in the study of the artistic anatomy of
+      man, study these bones with the bones of the lower limbs. Here we
+      do not follow this plan. In animals the sacrum and the coccyx, as
+      a matter of fact, clearly continue the superior border of the
+      skeleton of the trunk; hence we study them with the vertebral
+      column.
+
+_Vertebrae Constituting the Sacrum._--Bears, 5; dogs, 3; cats, 3;
+rabbits, 4; swine, 4; horses, 5; camels, 4; oxen, 5; sheep, 4.
+
+The sacrum is situated between the two iliac bones; with which it
+articulates, and contributes to the formation of the pelvis. It is
+obliquely placed, from before backwards, and from below upwards;
+immediately behind the lumbar section of the vertebral column; and is
+continued by the coccygeal vertebrae, which form the skeleton of the
+tail.
+
+It is triangular in outline, and is generally more narrow in proportion
+than in the human being. All things considered, it is more large and
+massive, and of greater density, in species which sometimes assume the
+upright posture, rather than in those which cannot assume that
+attitude; for example, the sacrum of the ape, of the bear, of the dog,
+and of the opossum are proportionately larger than those of the
+horse.[4]
+
+  [4] This is particularly striking only in those portions of the sacrum
+      that are not in relation with the other bones of the pelvis. We
+      think that the general form of this bone depends on the mode of
+      its connexions with the iliac bones and the extent of the
+      articular surfaces by which it is in contact with the latter.
+
+Its superior surface presents a crest, formed by the fusion of the
+spinous processes of the vertebrae which form it. In certain species
+these processes are attached only by their bases, and are separated from
+each other superiorly. In the pig they are wholly wanting.
+
+=The Coccygeal Vertebrae.=--These vertebrae, few in number (and sometimes
+ankylosed) in the human being, form in the latter a small series, the
+coccyx; which is inclined forwards, that is to say, towards the interior
+of the pelvis. In quadrupeds, on the contrary, their number is large;
+they are not ankylosed, and they form the skeleton of the caudal
+appendix.
+
+The first coccygeal vertebrae--that is, those which are next the
+sacrum--present characters which are common to those of other regions:
+they have a body, a foramen, and processes. As we trace them backwards,
+these characters become gradually effaced; and they become little more
+than small osseous cylinders simply expanded at their extremities.
+
+
+Direction and Form of the Spinal Column
+
+The curves of the vertebral column are, in quadrupeds, slightly
+different from those which characterize the human spine. First, instead
+of their being, as in the latter, curves in the antero-posterior aspect,
+because of the general attitude of the body, they are turned in the
+supero-inferior direction.
+
+The cervical region is not a single curve, as in the human being. It
+presents two: one superior, with its convexity looking upwards; the
+other inferior, the convexity of which is turned downwards. This
+arrangement reminds one of that of a console.
+
+The dorsal and lumbar regions are placed in a single curved line, more
+or less concave downwards; so that in the lumbar region there is no
+curve analogous to that which exists in man; a form which, in the
+latter, is due to the biped attitude--that is to say, the vertical
+position of the trunk. Briefly, there is in quadrupeds one dorso-lumbar
+curve; and not both a dorsal and a lumbar, with convexities in opposite
+directions.
+
+At the extremity of the dorso-lumbar region is the sacrum and the caudal
+appendix, which describe a curve of which the concavity is directed
+downwards and forwards.
+
+It is necessary to point out that it is not the curves of the three
+anterior portions of the spinal column which determine the form of the
+superior border of the neck and shoulders, and of the same part of the
+trunk. For the first portion, there is a ligament which surmounts the
+cervical region, and substitutes its modelling influence for that of the
+vertebrae. It is the _superior cervical ligament_, which arises from the
+spinous process of the first cervical vertebrae, and is inserted into the
+external occipital protuberance on the upper part of the posterior
+surface of the skull. The summits of the spinous processes of the
+vertebrae alone give form to the superior median border of the trunk. In
+this connection we here repeat that it is not the general curvature of
+the vertebral column which produces the withers, but the great length of
+the spinous process of the first vertebrae of the dorsal region.
+
+
+The Thorax
+
+The dorsal vertebrae form the posterior limit in man, and superior in
+quadrupeds, of the region of the trunk known as the _thorax_. A single
+bone, the sternum, is situated at the aspect opposite; the ribs bound
+the thorax on its sides.
+
+In its general outlines the thorax in quadrupeds resembles that
+of man--that is to say, that, as in the latter, the anterior
+portion--superior in the human being--is narrower than the part
+opposite. But the progressive widening takes place in a more regular and
+continuous fashion, so that it presents a more definitely conical
+outline. This purely conical form is nevertheless found in the human
+species, but only during infancy; the inferior portion of the thoracic
+cage being then widely expanded, because of the development of the
+abdominal viscera, which at that period are relatively large.
+
+But the proportionate measurements of the thorax are different. Indeed,
+we may recall that in man the thorax is flattened from before backwards,
+so that the distance between the sternum and the vertebral column is
+shorter than the distance from the rib of one side to the corresponding
+one of the opposite side (Fig. 5). In animals, on the contrary, it is
+flattened laterally. Its vertical diameter--measured from the sternum to
+the vertebral column--is greater than the transverse measurement (Fig.
+6).
+
+[Illustration: FIG. 5.--A TRANSVERSE SECTION OF THE THORAX OF A MAN
+PLACED VERTICALLY--THAT IS TO SAY, IN THE DIRECTION WHICH IT WOULD
+ASSUME IN A MAN PLACED IN THE ATTITUDE OF A QUADRUPED (A DIAGRAMMATIC
+FIGURE).
+
+1, Dorsal vertebra; 2, sternal region; 3, costal region of one side; 3',
+costal region of the other side.]
+
+From this results a peculiar arrangement of the muscles that we are able
+to bring directly into prominence, which presents points of interest
+from the point of view of the contraction of the subcutaneous layer.
+Indeed, in man the region occupied by the pectorals is very broad; it is
+a wide surface turned directly forward. In quadrupeds, this region of
+the pectorals is narrowed. It is not spread out, as in the preceding
+instances; and the appearance it presents is explained by the fact that
+the thorax is compressed laterally. If we examine the thorax on one of
+its lateral surfaces, the muscles, on the contrary, are more extended.
+We see the contour of the vertebral column, and the median part of the
+abdomen; and, especially in the horse, between the great dorsal and the
+great oblique of the abdomen, we find a large space, in which the ribs,
+with the intercostals which join them, are uncovered; the muscles in
+question separate the one from the other, under the influence, it would
+seem, of the great dimensions of the lateral wall of the thorax.
+
+[Illustration: FIG. 6.--A VERTICAL SECTION OF THE THORAX OF A QUADRUPED
+(DIAGRAMMATIC).
+
+1, Fifth dorsal vertebra; 2, sternal region; 3, costal region of one
+side; 3', costal region of the opposite side.]
+
+=The Sternum.=--The sternum is, in quadrupeds, directed obliquely
+downwards and backwards; its form varies in different species. In the
+carnivora, it consists of eight bones, irregularly cylindrical in form,
+being slightly flattened from within outwards, and thickened at their
+extremities. They remain separate, and this contributes elasticity and
+flexibility to the thorax. The first nine costal cartilages articulate
+directly with the sternum. The first of these cartilages articulates
+with a nodule situated a little above the middle of the first bone of
+the sternum.
+
+In the horse the sternum is flattened laterally in its anterior portion,
+and from above downwards in its posterior half. The six bones which
+form the sternum are connected by cartilage. The keel-shaped piece,
+situated in front of the sternum, is also cartilaginous. This process,
+but slightly marked posteriorly, becomes more and more prominent in
+front, and terminates at its anterior extremity by a prolongation,
+slightly curved backwards, which projects for some centimetres beyond
+the cavity in which the first costal cartilage is received. This process
+is known as the _tracheal process_, or _rostral cartilage_. The
+posterior extremity of the sternum, flattened from above downwards, ends
+in a cartilaginous plate; concave superiorly, and convex inferiorly:
+this is the abdominal prolongation, or _xiphoid appendix_.
+
+In the ox, the sternum is formed of two distinct bones, which are united
+by an articulation. One, the anterior, is short, and forms the first
+portion of the sternum; it is slightly flattened from side to side, and
+vertical in direction. The other, the posterior, is longer, and is
+formed by the fusion of several small bones; it is placed horizontally,
+and is flattened from above downwards. At the level of articulation of
+these two portions, and because of their different directions, the bone
+is bent. This bend occurs at the point of articulation of the second
+costal cartilage. On the superior border of the anterior segment the
+cartilage of the first rib is articulated. The xiphoid appendix, which
+is cartilaginous, is attached to the extremity of a long process of the
+last bone of the sternum.
+
+The shape of the anterior extremity of the sternum is influenced by the
+presence or absence of clavicles. We have seen that in some quadrupeds
+the clavicles are wanting. In the first case, this extremity is large,
+and approaches in shape to the corresponding part of the human sternum,
+which is so clearly designed to give a point of support to the anterior
+bone of the shoulder. In the second, on the contrary, this extremity is
+narrow.
+
+The sternum in birds is very different from that in mammalia, which we
+have been studying. It varies greatly in extent and shape, under the
+influence of certain conditions. To understand the cause of these
+variations it is necessary to remember that in man (as, indeed, in other
+animals; but the example of man, for that which follows, will be more
+striking, on account of the mobility of his upper limbs) the sternum
+gives origin to the pectoral muscles, and that these muscles are
+inserted into other parts of the thoracic limbs, designed by their
+contraction to draw the arms downwards, forwards, and inwards--that is,
+when these are in a state of abduction and in a horizontal direction,
+they draw them towards the anterior surface of the thorax and downwards.
+Now, this movement is similar to that made by birds during flight. It is
+necessary to add that, in the latter case, the more the displacement of
+the upper limbs has of force and extent, the more the pectoral muscles
+are developed.
+
+For these reasons, birds, in which, during flight, the movements of the
+thoracic limbs--the wings--are necessarily energetic, present a great
+development of the pectoral muscles; having consequently, because an
+extent of surface for the origin of the muscles commensurate with their
+development is necessary, a very large and peculiarly shaped sternum
+(Figs. 18, 6; and 21, 6). Indeed, not only is the sternum large, but,
+further, in order to form a deeper surface, proportionately adapted to
+the muscles which arise from and cover it, its anterior surface
+presents, in the median line, a prominent crest known as the _keel_.
+This prominence forms two lateral fossae. We cite as examples, the
+sternum of the eagle, the vulture, the falcon, and the hawk.
+
+All birds are not, however, equally adapted to flight, for in the
+domestic cock, which flies but a short distance, and badly, the sternum
+is less developed (Fig. 7); it is also diminished by slots, which
+diminish its surface. These slots, two on each side, are called from
+their position the internal and external slots. They are bounded by
+narrow, elongated, bony processes, an internal and an external; the
+expanded lower extremity of the latter overlaps the last inferior ribs
+(see p. 19). The part of the external border which surmounts this
+external process is hollowed out into grooves, which receive the
+inferior ribs, and terminates superiorly in an osseous projection known
+as _the costal prominence_.
+
+In the ostrich, the cassowary, and the apteryx, which run, but do not
+fly, the sternum has the form of a plate of bone slightly convex, but
+without a keel.
+
+[Illustration: FIG. 7.--STERNUM OF A BIRD (THE COCK): LEFT SIDE,
+EXTERNAL SURFACE.
+
+1, Keel; 2, internal slot; 3, external slot; 4, internal process; 5,
+external process; 6, inferior ribs; 7, costal process; 8, surface for
+articulation with the coracoid bone.]
+
+The shape of the sternum, correlated to the faculty of flight (or of
+swimming; apropos of which we may cite the penguin, of which the
+rudimentary wings resemble fins, and perform their functions only), or
+the absence of this faculty, has furnished the division of birds into
+two groups. In one are included, under the name _Carinates_ (_carina_,
+keel), those in which the sternum is provided with a keel; in the other
+division are those in which the sternum is not furnished with one. These
+latter, on account of their unique mode of progression, are more nearly
+allied to the mammals.
+
+The keel is developed in flying mammals (bats).
+
+=Ribs and Costal Cartilages.=--There are on each side of the thorax as
+many ribs as there are dorsal vertebrae. In animals, as in man, the ribs
+which articulate with the sternum by their cartilages are called _true_,
+or _sternal_ ribs; those whose cartilages do not articulate with the
+sternum are called _false_, or _asternal_. The longer ribs are those
+situated in the middle region of the thorax.
+
+The ribs are directed obliquely downwards and backwards, and this
+obliquity is more marked in the posterior ones than in the anterior.
+They are, however, less oblique than in the human being; what proves
+this is that the first rib in man is oblique, while in quadrupeds it is
+vertical.
+
+The curvature of the ribs is less pronounced in quadrupeds than in the
+human being, but this is not equal in all animals. The ribs of the bear
+are more curved than those of the dog; the latter has ribs more curved
+than those of the horse.
+
+Each rib, at its vertebral extremity, presents, from within outwards, a
+wedge-shaped head for articulation with two dorsal vertebrae, a neck, and
+a tuberosity. External to the tubercle are found some rough impressions,
+for muscular attachments, which correspond to the angle of the human
+rib.
+
+In the following table, we give the number and classification of the
+ribs of some animals:
+
+NUMBER OF THE RIBS ON EACH SIDE OF THE THORAX.
+
+                             Sternal.    Asternal.
+  Bear       14  divided into   9    and     5
+  Dog        13     "      "    9     "      4
+  Cat        13     "      "    9     "      4
+  Rabbit     12     "      "    7     "      5
+  Pig        14     "      "    7     "      7
+  Horse      18     "      "    8     "     10
+  Camel      12     "      "    8     "      4
+  Ox         13     "      "    8     "      5
+  Sheep      13     "      "    8     "      5
+
+The costal cartilages, by which the first ribs are united to the sternum
+(sternal ribs), whilst the latter are united one to the other without
+being directly connected with the sternum (asternal ribs), are, as a
+rule, in quadrupeds, directed obliquely downwards, forwards, and
+inwards; each forms, with the rib to which it belongs, an obtuse angle
+more or less open anteriorly. Their length is proportionate to that of
+the ribs. The cartilages, which are continued from the asternal ribs,
+unite and form the borders, directed obliquely downwards and forwards,
+of the fossa which is found at the inferior and posterior part of the
+thorax, and which forms the lateral limits of the epigastric region. In
+the dog and cat the ribs are thick and almost cylindrical; the costal
+cartilages are thicker at the margin of the sternum than at their costal
+extremity. In the ox, the ribs are flattened laterally and are very
+broad, the more so as we examine a portion further from the vertebral
+column. From the second to the twelfth they are quadrangular in the
+superior fourth, and thicker than in the rest of their extent. The first
+costal cartilage is vertical; the following ones are progressively more
+oblique in a direction downwards and forwards. The four or five
+cartilages which succeed the first unite with slight obliquity to the
+sternum; their union with that bone gives the impression of a very
+strong, well-knit apparatus. The costal cartilages which unite with the
+sternum are flattened laterally in the portions next the ribs, and
+flattened from front to back in the rest of their extent.
+
+In the horse the ribs increase in length from the first to the ninth;
+they are flattened from without inwards, and increase in width from the
+first to the sixth or seventh, and the following ones become narrower.
+The costal cartilages, from the second to the eighth, are, as in the ox,
+at first flattened laterally, near the ribs; while near the sternum they
+are flattened from front to back.
+
+In birds, the ribs are each furnished with a flat process (Fig. 18, 10),
+which springs from the posterior border, is directed backwards, and
+overlaps the external surface of the succeeding rib. These processes are
+not found, as a rule, on the first or last ribs.
+
+As for the costal cartilages, they are, as a rule, ossified, and receive
+the name of inferior ribs (Fig. 18, 11), united to the preceding
+(superior ribs; Fig. 18, 9) by articulation; by the other extremity they
+are joined to the sternum; the first superior ribs generally want them.
+Sometimes the last inferior rib becomes connected with the one that
+precedes it, not articulating with the sternum; and thus recalls the
+relations of the asternal ribs which we have noticed in our study of the
+mammals.
+
+In the bat, as in birds, the costal cartilages are ossified.
+
+
+THE ANTERIOR LIMBS[5]
+
+  [5] Consult Figs. 21, 33, 34, 38, 39, 46.
+
+The anterior limbs, homologous to the upper limbs in man, are formed, as
+in the latter, of four segments: the shoulder, the arm, the forearm, and
+the hand. These limbs, considered in the vertebral series, present
+themselves under very different aspects, which are determined by the
+functions they are called upon to perform.
+
+They constitute the forepaw in terrestrial mammals; in aerial
+vertebrates they form wings; in aqueous mammals they act as paddles. In
+whatever series we study them, we can readily find the relationship of
+the different parts; it is very easy to recognise the same bones in the
+upper limbs of the human being, the wings of the bat (Fig. 8) and of
+birds (Fig. 21), and in the anterior paddles of the seal (Fig. 9) and of
+the dolphin.
+
+[Illustration: FIG. 8.--ANTERIOR LIMB OF THE BAT: LEFT SIDE, ANTERIOR
+SURFACE.
+
+1, Clavicle; 2, scapula; 3, humerus; 4, radius; 5, cubitus; 6, carpus;
+7, thumb; 8, metacarpus; 9, phalanges.]
+
+In quadrupeds, the shoulder and arm are hidden, the latter more or less
+completely, in the muscular mass which binds it to the lateral wall of
+the trunk; so that the anterior limbs only present; free from the trunk:
+the elbow, forearm, and hand.
+
+
+The Shoulder
+
+In some vertebrates, the shoulder is formed of two bones--the scapula
+and clavicle; in others of only one bone--the scapula; the clavicle in
+this case does not exist.
+
+=The Scapula or Omoplate.=--The scapula is situated on the lateral
+surface of the thorax, and is directed obliquely, from above downwards
+and from behind forwards.
+
+We must first recall, so as to be able to make a comparison, that in man
+this bone is placed at the posterior surface of the thoracic cage; so
+that if we look at the human thorax on one of its lateral aspects we see
+chiefly the external border of the scapula; it is the external surface
+(homologous to the posterior surface of the human scapula) which we see
+in its full extent when we look on the same surface of the thorax in
+quadrupeds.
+
+[Illustration: FIG. 9.--ANTERIOR LIMB OF THE SEAL: LEFT SIDE, EXTERNAL
+SURFACE.
+
+1, Scapula; 2, humerus; 3, radius; 4, ulna; 5, carpus; 6, metacarpus; 7,
+phalanges of the fingers.]
+
+To sum up, if we fancy the human being in the position of the quadruped,
+the scapula will have its surfaces almost parallel to the ground (Fig.
+10); while in quadrupeds, the surfaces are situated in a plane which is
+almost perpendicular to the ground (Fig. 11). This position of the
+scapula in an almost vertical plane is designed to give the necessary
+point of support to the osseous columns that form the skeleton of the
+other portions of the anterior limbs.
+
+Because of this position of the scapula (Figs. 12 and 13), the spinal
+border is superior, the cervical, anterior, and the axillary, posterior.
+In direct contrast to what obtains in the human scapula, the spinal
+border is the shortest of the three; except in the bat, and the
+majority of the cetaceans.
+
+[Illustration: FIG. 10.--SITUATION AND DIRECTION OF THE SCAPULA IN THE
+HUMAN BEING, THE TRUNK BEING HORIZONTAL, AS IN QUADRUPEDS. VERTICAL AND
+TRANSVERSE SECTION OF THE THORAX (DIAGRAMMATIC FIGURE).
+
+1, Contour of the thorax; 2, 2, the scapula.]
+
+[Illustration: FIG. 11.--POSITION AND DIRECTION OF THE SCAPULA IN
+QUADRUPEDS. VERTICAL AND TRANSVERSE SECTION OF THE THORAX (DIAGRAMMATIC
+FIGURE).
+
+1, Contour of the thorax; 2, 2, the scapula.]
+
+In certain animals (in the ungulates [_hoofed_[6]]--pigs, oxen, sheep,
+horses) the superior, or spinal, border of the scapula is surmounted by
+a cartilage called _the cartilage of prolongation_.
+
+  [6] For the definition of the word _hoofed_, see p. 37.
+
+This is the cause why the border to which it is fixed is so slightly
+noticeable under the skin in these animals; indeed, in the upper part,
+the bone and cartilage are not distinguishable in the contour of the
+corresponding region of the back; being applied to the lateral surfaces
+of the spinous processes, the prominence formed by the extremities of
+which is directly continuous with the plane of the scapula (Fig. 16).
+
+[Illustration: FIG. 12.--LEFT SCAPULA OF THE HUMAN BEING, POSTERIOR
+SURFACE, PLACED IN THE POSITION WHICH IT WOULD OCCUPY IN THE SKELETON OF
+A QUADRUPED.
+
+1, Cervical border; 2, spinal border; 3, axillary border; 4,
+supraspinous fossa; 5, subspinous fossa; 6, scapular spine; 7, glenoid
+cavity; 8, coracoid process; 9, acromion process.]
+
+[Illustration: FIG. 13.--LEFT SCAPULA OF A HORSE: EXTERNAL SURFACE.
+
+1, Cervical border; 2, spinal border--the scapula here represented,
+being from a hoofed animal, has a cartilage of extension attached to its
+spinal border; 3, axillary border; 4, supraspinous fossa; 5, subspinous
+fossa; 6, spine of the scapula; 7, glenoid cavity; 8, coracoid process.
+The scapula of the horse has no acromion process, but it is easy, if we
+compare the human scapula, to judge of the position which this process
+would occupy if it were present.]
+
+In quadrupeds whose scapula, on the contrary, is wanting in the
+cartilage of prolongation (in the _clawed_,[7] such as the cat and dog),
+the superior border of the scapula is visible, especially when the
+animal is resting on its fore-limbs, particularly when it crouches; at
+such a time the skin is markedly raised by that border; and the spinous
+processes of the vertebrae, beyond which it projects, occupy the bottom
+of a fossa (Fig. 15). The internal surface of the scapula is turned
+towards the ribs; it is known, as in man (in whom this surface is
+anterior), as the subscapular fossa.
+
+  [7] For the definition of this word, see p. 37.
+
+[Illustration: FIG. 14.--VERTICAL AND TRANSVERSE SECTION, AT THE SITE OF
+THE SHOULDERS, OF THE THORAX OF THE HORSE (DIAGRAMMATIC FIGURE).
+
+1, Outline of the thorax at the level of the third dorsal vertebra; 2,
+2, scapula; 3, spinal border of the scapula; 4, cartilage of
+prolongation; 5, contour of the skin.]
+
+[Illustration: FIG. 15.--VERTICAL AND TRANSVERSE SECTION, AT THE PLANE
+OF THE SHOULDERS, OF THE THORAX OF A DOG (DIAGRAMMATIC FIGURE).
+
+1, Outline of the thorax at the level of the third dorsal vertebra; 2,
+2, scapula; 3, spinal border of the scapula; 4, contour of the skin.]
+
+Its external surface is divided into two parts by the spine of the
+scapula; which, in some animals, terminates inferiorly in a flat and
+clearly distinct process, the homologue of the acromion process of the
+human scapula. The two regions separated by the spine are known as the
+supraspinous fossa and the infraspinous fossa. The supraspinous fossa is
+anterior to the spine, and the infraspinous is posterior to it. The
+surfaces of the scapula are, in quadrupeds, flatter than in the human
+being, and in particular the subscapular fossa, which is also less
+concave. Some authors attribute this to the lesser curvature of the ribs
+in quadrupeds. A few words will suffice to prove that there must be
+another reason. The scapula is not in immediate contact with the ribs;
+the subscapular fossa is not moulded on them. Besides, the form of the
+scapula is, as in other parts of the skeleton, dependent on the
+disposition of muscles, and the development of these latter is
+correlated to the extent and energy of the movements which the
+individual is able or required to execute. But the movements which
+those muscles produce (more especially the rotation of the humerus) are,
+in quadrupeds, less extensive than in the human being; and,
+consequently, the muscles which produce them are, proportionally, less
+strongly developed. The inferior angle (superior and external in man),
+situated at the junction of the cervical and axillary borders, presents
+the glenoid cavity, which, looking downwards, receives the articular
+surface of the superior extremity of the bone of the arm--that is to
+say, the head of the humerus. Above this cavity, on the lower part of
+the cervical border, is situated a tubercle which reminds us of the
+coracoid process of the human scapula. The region occupied by the
+glenoid cavity is separated from the body of the bone by a
+constriction--the neck of the scapula.
+
+In birds the scapula is elongated in a direction parallel to the
+vertebral column, and very narrow in the opposite (Fig. 18): it is also
+flat, and has no spine. Its coracoid process is represented by a
+peculiar bone--the coracoidean or coracoid bone--which we shall describe
+later on when we come to the study of the clavicle and of the anterior
+region of the shoulder (see p. 26).
+
+=The Clavicle.=--The clavicle is found only in the human being, and in
+animals whose anterior limbs, possessing great freedom of movement in
+all directions, require that the scapula should possess a point of
+support which, while affording this, can be displaced with it, or draw
+it in certain directions. Now, this point of support is furnished by the
+clavicle.
+
+In animals possessed of hoofs (ungulates), such as the sheep, ox, and
+horse, the clavicle does not exist. Indeed, in them the freedom of
+movement of the anterior limbs is limited; they move by projection in
+the forward and backward directions only; they merely fulfil the
+functions of giving support to and carrying about the body. The clavicle
+is rudimentary in the cat and the dog; in the cat it is a small,
+elongated bone (Fig. 16), 2 centimetres in length, thin and curved,
+connected with the sternum and the scapula by ligamentous bundles. In
+the dog it is represented by a small osseous plate only (Fig. 17),
+which is not connected with any of the neighbouring bones.
+
+It is on the deep surface of a muscle which passes from the head and
+neck to the humerus (mastoido-humeral, a muscle common to the arm, neck,
+and head) in which this rudimentary bone is found to be developed.
+
+The clavicle exists in perfect state in mammals which use their limbs
+for digging, grasping, or flying; the insectivora (hedgehog, mole) and
+some rodents (squirrel, woodchuck) are provided with it.
+
+The cheiroptera (bats) possess an extremely well-developed clavicle, on
+account of the varied movements which their thoracic limbs execute.
+
+[Illustration: FIG. 16.--LEFT CLAVICLE OF THE CAT: SUPERIOR SURFACE
+(NATURAL SIZE).
+
+1, Internal extremity; 2, external extremity.]
+
+[Illustration: FIG. 17.--CLAVICLE OF THE DOG (NATURAL SIZE).]
+
+This formation of the shoulder which favours flight in the bat is even
+more remarkable in birds. In these latter (Fig. 18) the clavicles, fused
+together by their lower extremities, form one bone, having the shape of
+the letter V or U, which is known as the _fourchette_; this bone, acting
+as a true spring, keeps the shoulders apart, and prevents their
+approximation during the energetic movements which flight necessitates.
+
+In birds whose power of flight is strong, the two limbs of this bone are
+widely separated and thick, and the fourchette is U-shaped. Those whose
+flight is awkward and but slightly energetic have the limbs of the
+fourchette slender; they unite at a more acute angle, and the bone is V
+shaped.
+
+Furthermore, a bone named the _coracoid_ joins the scapula to the
+sternum; this bone, often fused with the scapula, where it contributes
+to the formation of the glenoid cavity, represents in birds the coracoid
+process of the human scapula. If we fancy this process directed
+inwards, and sufficiently lengthened to join the sternum, we shall have
+an idea of the disposition of the bone we are now discussing, and the
+reasons for which the name has been chosen by which it is designated.
+The coracoid bone, like the fourchette which it reinforces, offers to
+the wings a degree of support proportionate to the efforts developed by
+those limbs; for this reason it is thick and solid in birds of powerful
+flight.
+
+[Illustration: FIG. 18.--SKELETON OF THE SHOULDER OF A BIRD (VULTURE):
+ANTERO-EXTERNAL VIEW OF THE LEFT SIDE.
+
+1, Left clavicle; 2, inferior portion of the right clavicle, forming by
+its ankylosis with that of the other side the fourchette; 3, coracoid
+bone; 4, scapula; 5, articular surface for humerus; 6, superior half of
+the sternum; 7, keel of sternum; 8, spinous process of the dorsal
+vertebrae; 9, superior ribs; 10, process of one of these ribs; 11,
+inferior ribs.]
+
+The superior extremity of each branch of the fourchette, at the level of
+its junction with the coracoid and the scapula, bounds, with these
+latter, a foramen which gives passage to the tendon of the elevator
+muscle of the wing, or small pectoral. The importance of the fourchette
+being, as we have seen, in proportion to the movements of flying, it is
+easy to understand that the bone is not found in the ostrich.
+
+
+The Arm
+
+A single bone, the humerus, forms the skeleton of this portion of the
+thoracic limb.
+
+=The Humerus.=--The bone of the arm is, in quadrupeds, inclined from
+above downwards and from before backwards.
+
+It is, with relation to other regions, short in proportion as the
+metacarpus is elongated, and as the number of digits is lessened. In the
+horse, for example, whose metacarpus is long, and in which but one digit
+is apparent, the humerus is very short. The slight development in length
+of the humerus explains its close application to the side of the animal
+as far as the elbow.
+
+In animals in which the humerus is longer, the bone is slightly free, as
+well as the elbow, at its inferior extremity. Later on we will return to
+the consideration of this peculiarity and of the proportions of the
+humerus, after we have studied the other parts of the fore-limbs.
+
+The humerus in quadrupeds is inflected like the letter S; in man this
+general form is less accentuated, the humerus being almost straight. On
+its body, which appears twisted on its own axis, we find the
+musculo-spiral groove,[8] which crosses the external surface, and is
+very deep in some animals. Above this groove, and on the external
+surface, there exists a rough surface which is the impression of the
+deltoid. In some species this rugosity is very prominent, and is called
+_the tuberosity of the deltoid_; it is prolonged downwards by a border
+which forms the anterior crest of the musculo-spiral groove and limits
+this latter in front. The external border of the bone, or posterior
+crest of the groove, limits it behind.
+
+  [8] It would be going outside our province to discuss whether the
+      humerus is really twisted on its axis. This question, often
+      discussed, has been solved in some recent works in the following
+      manner: the humerus has undergone torsion at the level of its
+      superior extremity, and not at the level of its body; this does
+      not authorize us further to accord any definite sense to the
+      denomination 'groove of torsion' (musculo-spiral groove). That
+      which we must especially remember in connection with this fact,
+      is, as we shall afterwards see, the difference of direction which
+      the articular head presents according as the torsion has been more
+      or less considerable: because this is established, according to
+      the same order, in man and in quadrupeds.
+
+The superior extremity is enlarged, and remarkable in three portions
+which it presents; these are: an articular surface and two tuberosities.
+
+The articular surface, or head of the humerus, smooth and round, is in
+contact with the glenoid cavity of the scapula. This head in the human
+skeleton is directed upwards and inwards; in quadrupeds its direction is
+upwards and backwards. The inferior extremity, having in both one and
+the other its long axis directed transversely, and the point of the
+elbow looking backwards in all, the result is that the head of the
+humerus is not situated vertically above the same regions; in the first,
+it is almost directly above the internal part of this extremity; in the
+latter, it is situated above its posterior surface, or the point of the
+elbow in the complete skeleton. This difference of direction is
+correlated with the position of the scapula, the glenoid cavity of
+which, as we have already seen, is in man turned outwards, whereas in
+quadrupeds it looks downwards. In the latter case the scapula
+consequently rests on the head of the humerus; and this position is most
+favourable for the performance of the functions which the anterior limbs
+have to fulfil in these latter.
+
+Of the tuberosities of the head of the humerus, one is situated on the
+external aspect--it is the great tuberosity, or _trochiter_; the other
+is placed internally--it is the small tuberosity, or _trochin_. The
+great tuberosity is divided into three parts--summit, convexity, and
+crest; these different parts give insertion to the muscles of the
+shoulder. We recollect that the facets (anterior, middle, and posterior)
+of the great tuberosity of the humerus in man give attachment to the
+muscles of the same region. The head of the humerus in the human body
+projects above the tuberosities. We shall see afterwards, when dealing
+with some special quadrupeds, that in some of these, on the other hand,
+the tuberosities are on a higher level than the articular head of the
+bone. Between the two tuberosities is the bicipital groove.
+
+In man, the superior extremity of the humerus, although covered by the
+deltoid, reveals its presence by elevating the corresponding portion of
+the latter. In quadrupeds, the anterior part of this extremity, although
+similarly covered by muscular bundles, produces a prominence under the
+skin. This prominence is situated at the summit of the angle formed by
+the opposing directions of the scapula and the bone of the arm, and
+constitutes what is known by the name of the _point of the shoulder_, or
+of the _point of the arm_.
+
+The inferior extremity, transversely enlarged, presents an undulating
+articular surface, which reminds us of the trochlea and the condyle of
+the human humerus; on which, however, the condyle is more sharply
+defined from the trochlea.
+
+In the human skeleton, the internal lip of the trochlea descends lower
+than the external; and also lower than the condyle. In the bear, the
+cat, and the dog, it is the same. In the ox and the sheep, the condyle
+is lower than the trochlea, but only very little lower. In the horse the
+arrangement is still the same, but a little more accentuated.
+
+On the lateral parts of this extremity we find: internally, a
+prominence, the epitrochlea; and, externally, another, the epicondyle.
+It is from this latter that the crest arises, which, passing upwards,
+forms the posterior limit of the groove of torsion.
+
+The two prominences, which we have just described from a general point
+of view, present special arrangements which it is necessary to point
+out. When we examine the form of the outline of the inferior extremity
+of the humerus in man, the bear, the cat, the dog, the ox, and the
+horse, we find in following this order that the extremity tends to
+become narrow transversely, and that the epicondyle and the epitrochlea
+are less and less prominent on the external and internal aspects
+respectively. These two processes, indeed, project backwards; the
+epitrochlea always remaining more developed than the epicondyle. Because
+of this projection backwards, the cavity situated on the posterior
+surface of the inferior extremity, the olecranon fossa, is very deep,
+more so than in the humerus of man. Its borders being thus formed by the
+two processes, are very prominent. In front we find the coronoid fossa,
+which is less deep than that of which we have just spoken.
+
+There exists in some mammals an osseous canal, situated above the
+epitrochlea, and known as the _supratrochlear canal_ (Fig. 19). It is
+bounded by a plate of bone which at its middle portion is detached from
+the shaft of the humerus, and blends with the latter at both its
+extremities. The brachial artery and median nerve pass through the
+foramen.
+
+[Illustration: FIG. 19.--INFERIOR EXTREMITY OF THE LEFT HUMERUS OF A
+FELIDE (LION).
+
+1, Epitrochlea; 2, supra-epitrochlear foramen.]
+
+[Illustration: FIG. 20.--INFERIOR EXTREMITY OF THE LEFT HUMAN HUMERUS,
+SHOWING THE PRESENCE OF A SUPRATROCHLEAR PROCESS.
+
+1, Epitrochlea; 2, supra-epitrochlear process.]
+
+A similar condition is sometimes found, as an abnormality, in
+man, which presents itself under the following aspect (Fig.
+20): an osseous prominence more or less long, in the shape of a
+crochet-needle--supra-epitrochlear process--situated 5 or 6 centimetres
+above the epitrochlea; the summit of this process gives attachment to a
+fibrous band, which is inserted by its other end into the epitrochlea
+and the internal intermuscular aponeurosis. The fibro-osseous ring thus
+formed gives passage to the brachial artery and the median nerve, or in
+case of a premature division of this artery to the ulnar branch of the
+same.[9]
+
+  [9] For further details of this anomaly, see Testut, 'The Epitrochlear
+      Process in Man' (_International Journal of Anatomy and
+      Physiology_, 1889); A. Nicolas, 'New Studies on the Supratrochlear
+      Process in Man' (_Review of Biology of the North of France_, t.
+      iii., 1890-1891).
+
+There is also found in some mammals a perforation of the thin plate of
+bone which, in others, separates the olecranon fossa from the coronoid.
+This perforation is sometimes found as an abnormality in the human
+humerus.
+
+As does the sternum and the skeleton of the shoulder, the humerus of
+birds presents differences correlated to the functions which the
+thoracic limbs are destined to fulfil. Lying on the side of the thorax,
+directed obliquely downwards and backwards (Fig. 21), it is
+proportionately longer in individuals of powerful flight than in those
+which fly less or not at all. In the vulture it projects beyond the
+posterior part of the pelvis; in the cock it does not even reach the
+anterior border of the same. To these differences in length are added
+differences in volume and in the development of the processes which
+serve for muscular attachment, which are more considerable in birds of
+powerful flight.
+
+The humerus is so placed that the radial border, external in man and
+quadrupeds, looks upwards, with the result that the surface of the bone
+of the arm, which in these latter is anterior, in the former looks
+outwards. The humeral head, which is turned forwards and a little
+inwards, is convex and elongated in the vertical direction. Behind and
+above this head is found a crest for the insertion of muscles. It is the
+same for the region below, where there is a tuberosity whose inferior
+surface presents a pretty large opening which looks inwards to a fossa
+from the floor of which a number of minute openings communicate with the
+interior of the bone. This is the pneumatic foramen of the humerus.
+
+It is of interest to remember in connection with this subject that in
+birds, in keeping with the conditions of flight, every system of organs
+is adapted to diminish the weight of the body. We particularly draw
+attention to the osseous framework, the structure of which is such that
+the weight of the animal is greatly lessened. This condition is secured
+by the pneumaticity. The bone consists of a cover of compact tissue,
+which, instead of enclosing marrow, is hollowed out by cavities which
+contain air, and communicate with special pouches, the air-sacs, which
+are appendages of the lungs.[10]
+
+  [10] The presence of air in the bones does not seem to be always
+       associated with the power of flight; as a matter of fact, we find
+       air spaces in the bones of some birds which do not fly (E. J.
+       Marey, 'The Flight of Birds,' Paris, 1890, p. 51).
+
+[Illustration: FIG. 21.--SKELETON OF A BIRD (VULTURE): LEFT SURFACE.
+
+1, Cranium; 2, face; 3, cervical vertebrae; 4, spinous processes of the
+dorsal vertebrae; 5, coccygeal vertebrae; 6, sternum; 7, keel; 8, superior
+ribs; 9, inferior ribs; 10, clavicle; 11, coracoid bone (for the details
+of the skeleton of the shoulder, see Fig. 18); 12, humerus; 13, radius;
+14, ulna; 15, carpus; 16, hand (for details of the skeleton of this
+region, see Fig. 31); 17, ilium; 18, ischium; 19, pubis (for the details
+of the pelvis, see Fig. 46); 20, femur; 21, tibia; 22, fibula; 23,
+osseous nodule, which some anatomists think represents the calcaneum; it
+is the sole vestige of the tarsus; 24, metatarsus; 25, foot; 26, first
+toe (for the details of the skeleton of the foot, see Fig. 48).]
+
+The antibrachial extremity of the humerus is flattened from without
+inwards. It terminates in two articular surfaces, which articulate with
+the radius and ulna.
+
+The olecranon process of the ulna being slightly developed, it follows
+that the olecranon fossa is not large; neither is the coronoid.
+
+
+General View of the Form of the Forearm and Hand
+
+We now proceed to the study of the two regions of the fore-limbs which
+present the greatest variety in regard to the number of bones and also
+in regard to form and proportions. These two regions are the forearm and
+the hand.
+
+It is first of all necessary to say that in man, when the fore-limb
+hangs beside the body, and the dorsum of the hand looks backwards, the
+two bones of the forearm are parallel, and that this position is known
+by the name of _supination_. It is also necessary to remember that there
+is another attitude, in which the radius, crossing the ulna, and
+carrying the hand with it, displaces the latter in such a way that the
+palmar surface looks backwards. This second position is known as
+_pronation_.
+
+Let us now suppose that a man wishes to walk in the attitude of a
+quadruped. It will be necessary, in order that his upper limbs, being
+for the moment anterior ones, may act as members of support, to place
+the forearm in pronation, in order that, as is more normal, the hands
+may rest on the ground by their palmar surfaces. In this position the
+radius, being rotated on its own axis at its upper extremity and around
+the ulna in the rest of its extent, shall have its inferior extremity
+situated on the inner side of the corresponding extremity of the latter.
+
+Such is the situation of the bones of the forearm and the attitude of
+the hand in quadrupeds. In short, quadrupeds have their anterior members
+in the position of pronation.
+
+The individual whom we have just supposed placed in the attitude of a
+quadruped would be able to maintain this position by pressing on the
+ground more or less extensive portions of his hands; the whole palm of
+the hand may be applied to the ground (Fig. 22); or the fingers
+only--that is to say, the phalanges (Fig. 23); or the extremities of
+the fingers only--that is to say, the third phalanges (Fig. 24). This
+last position, which is certainly difficult to maintain, should here be
+regarded rather as theoretical.
+
+We shall meet with each of these modes of support in certain groups of
+animals. Thus, the bear, badger, and the majority of rodents, have the
+paws applied to the ground by the whole extent of the palmar surface of
+the hand, from the wrist to the tips of the fingers. They are therefore
+called plantigrade, from the analogy, in this case, of the palm of the
+hand to the plantar surface, or sole of the foot.
+
+[Illustration: FIG. 22.--THE HUMAN HAND RESTING FOR ITS WHOLE EXTENT ON
+ITS PALMAR SURFACE: LEFT SIDE, EXTERNAL SURFACE.]
+
+In others, such as the lion, tiger, panther, cat, wolf, and fox, the
+support is made no longer on the whole extent of the palmar surface, but
+on the corresponding surface of the fingers only--the metacarpus is
+turned back, and, consequently, the wrist--that is to say, the
+carpus--is removed from the ground. These are the digitigrades.
+
+Lastly, the ruminants (sheep, oxen, deer, etc.), and also the pig, ass,
+and horse, rest on the third phalanx only. In them not only is the
+metacarpus turned back, but also the two first phalanges. The wrist is
+very far removed from the ground. In these animals, the third phalanx is
+enclosed in a case of horn, a nail (the hoof), and because the support
+of the limb is on that nail, the name of unguligrades has been given
+them. Nevertheless, as the point of support is on the third phalanx,
+which is also known by the name of phalangette, we are of opinion that,
+in order to specify definitely, although they walk on their fingers, as
+do the digitigrades, the support is provided not by the whole extent of
+those appendages, they might receive the name of phalangettigrades.
+
+[Illustration: FIG. 23.--THE HUMAN HAND RESTING ON ITS PHALANGES: LEFT
+SIDE, EXTERNAL SURFACE.]
+
+[Illustration: FIG. 24.--THE HUMAN HAND RESTING ON THE TIPS OF SOME OF
+ITS THIRD PHALANGES: LEFT SIDE, EXTERNAL VIEW.]
+
+It is necessary among the ruminants to make an exception of the camel
+and the llama, which are digitigrades.
+
+Just in proportion as the hand is raised from the ground, as we have
+just seen in passing from the plantigrades to the digitigrades and
+unguligrades, the number of bones of that region diminishes, the bones
+of the forearm coalesce, and the ulna tends to disappear; the hand
+becomes less and less suitable for grasping, climbing, or digging, so as
+to form an organ exclusively adapted for walking and supporting the
+body.
+
+Thus, the bear (plantigrade) has five digits, and the power of
+performing the movements of supination and pronation. Indeed, we know
+with what facility this animal is able to move his paws in every
+direction, and climb a tree by grasping it with his fore-limbs. It is
+well known, however, that no animal except the ape can perform the
+movements of rotation of the radius around the ulna with the same
+facility as man; and that none possesses the same degree of suppleness,
+extent, and variety of movements of the forearm and hand.
+
+In the digitigrades there is one finger which is but slightly developed,
+and which is always removed from the ground--that is, the thumb: there
+is also a little less mobility of the radius around the ulna.
+
+In the ungulates the limbs are simply required to perform the movements
+of walking, and form veritable columns of support, which become the more
+solid as they are less divided. The bones of the forearm are fused
+together; there is therefore no possibility of rotation of the radius
+around the ulna. The metacarpus is reduced to a single piece, which in
+the horse constitutes what is known as the _canon_. The number of digits
+becomes diminished, so that in ruminants there are not more than two,
+and in the horse but one. We should, however, add that, up to the
+present, we have taken into account only perfect digits, those that rest
+on the ground. We shall see further on that there exist supplementary
+digits, but that they are only slightly developed, and are represented
+in some cases by mere osseous spurs; it is this fact that has permitted
+us to ignore them in the general study which we have just made.
+
+Because, as we have already said, the unguligrades have the inferior
+extremity of the digit encased in a horny sheath, which forms the hoof
+of the horse and the corresponding structures (_onglons_) in the ox,
+those animals have been placed in a special group, which is based on
+that peculiarity--that is, the group of ungulate mammals.
+
+The plantigrades and digitigrades, of which the paws have their surfaces
+of support strengthened by an epidermic sole and fatty pads, have the
+free extremities of the third phalanges covered on their dorsal surface
+by nails or claws; hence they are named _unguiculate_ mammals.
+
+The bat and birds have the bones of the forearm so arranged that the
+radius cannot rotate around the ulna. This is necessary in order that
+during flight, when the wing is being lowered, the radius and hand shall
+not be able to turn; for, if such rotation took place, each stroke of
+the wing would place it in a vertical position, which would occasion a
+loss of resistance incompatible with the effect to be obtained.
+
+
+The Forearm
+
+The skeleton of the forearm in quadrupeds is vertical in direction;
+consequently, it forms with the arm an angle open anteriorly; this is
+well seen on examining the lateral surface. If we examine it on its
+anterior surface, we find a slight obliquity directed downwards and
+inwards. In animals in which the bones of the forearm are separate--that
+is to say, susceptible of supination and pronation--we find a more close
+resemblance to those of the human skeleton. The ulna, the superior
+extremity of which always projects beyond that of the radius, has a
+shaft which gradually narrows from above downwards. Its inferior
+extremity is terminated by a round head in those animals in which the
+ulna is fully developed; in others, as it is atrophied, it ends in a
+thin, long process.
+
+The ulna presents at its superior extremity a posterior process, the
+olecranon, which forms the point of the elbow. We find on the anterior
+surface of the same, another process, the coronoid.
+
+It is necessary to dwell on the relations of these parts. In man the
+head of the radius is situated at the anterior part of the external
+surface of the superior extremity of the ulna (Fig. 25); indeed, the
+small sigmoid cavity with which the head articulates is situated on the
+outer side of the coronoid process, and this apophysis is placed in
+front. In the plantigrades and digitigrades the head of the radius is
+placed still more forward, so much so that it is situated almost in
+front of the superior extremity of the ulna (Fig. 26). In the
+unguligrades it is placed directly in front of this latter (Fig. 27).
+
+Further, the displacement of the radius is made at the expense of the
+superior extremity of the neighbouring bone; the radius appears to
+appropriate more and more the parts which in man belong exclusively to
+the ulna--for example, the coronoid process. In the plantigrades and the
+digitigrades half of the process still belongs to the ulna and the
+remainder to the radius. In the ungulates--the horse, for example--the
+coronoid process belongs to the radius; the ulna, situated behind the
+latter, is correspondingly diminished in size.
+
+[Illustration: FIG. 25.--SUPERIOR EXTREMITY OF THE BONES OF THE HUMAN
+FOREARM: LEFT SIDE, SUPERIOR SURFACE.
+
+1, Radius; 2, ulna; 3, olecranon process; 4, coronoid process.]
+
+[Illustration: FIG. 26.--SUPERIOR EXTREMITY OF THE BONES OF THE FOREARM
+OF THE DOG: LEFT LIMB, SUPERIOR SURFACE.
+
+1, Radius; 2, ulna; 3, olecranon process; 4, coronoid process.]
+
+In brief, when we study this region of the skeleton in plantigrades,
+then in digitigrades, and finally in unguligrades, we find a kind of
+progressive absorption of one of the two bones (ulna) by the other
+(radius), which thus becomes the more developed.
+
+It is easy to explain this partial disappearance of the ulna. When the
+forearm is capable of performing the movements of pronation and
+supination, the ulna is completely developed, for it is in its small
+sigmoid cavity that the head of the radius revolves, and it is around
+its inferior extremity, the head, that the corresponding extremity of
+the radius turns. But when the movements of rotation of the forearm do
+not exist, the inferior extremity of the ulna becomes functionally
+useless and disappears. As to its role in the movements of the region of
+the wrist, that is nil, for we may remember--we will observe it again
+when we come to treat of the articulations--that the hand articulates
+with the radius alone (radio-carpal articulation); this is the reason
+that, when the forearm possesses the fullest mobility, the hand follows
+the movements which that bone makes around the ulna.
+
+[Illustration: FIG. 27.--SUPERIOR EXTREMITY OF THE BONES OF THE FOREARM
+OF THE HORSE: LEFT LIMB, SUPERIOR SURFACE.
+
+1, Radius; 2, ulna; 3, olecranon process; 4, coronoid process.]
+
+It is not so with the articulation at the elbow-joint; there it is the
+ulna, which, with the humerus, forms the essential parts (humero-ulnar
+articulation); its olecranon process limits the movement of extension
+of the forearm. It is for this reason that, even in those quadrupeds in
+which the ulna is atrophied, the olecranon process presents a relatively
+considerable degree of development.
+
+[Illustration: FIG. 28.--INFERIOR EXTREMITY OF THE BONES OF THE FOREARM
+OF A MAN: LEFT SIDE, POSTERIOR SURFACE, POSITION OF SUPINATION.
+
+1, Radius; 2, ulna; A, groove for the long abductor and short extensor
+muscles of the thumb; B, groove for the radial muscles; C, groove for
+the long extensor of the thumb; D, groove for the special extensor of
+the index finger and of the common extensor of the fingers; E, groove
+for the proper extensor of the little finger; F, groove for the
+posterior ulna.]
+
+[Illustration: FIG. 29.--INFERIOR EXTREMITY OF THE BONES OF THE FOREARM
+OF THE DOG: LEFT SIDE, ANTERIOR SURFACE, NORMAL POSITION--THAT IS, THE
+POSITION OF PRONATION.
+
+1, Radius; 2, ulna; A, groove for the long abductor and for the short
+extensor of the thumb; B, groove for the radials; D, groove for the long
+extensor of the thumb, the special extensor of the index-finger, and the
+common extensor of the fingers; E, groove for the special extensor of
+the little finger.]
+
+We know that on the posterior surface of the inferior extremity of the
+bones of the human forearm are grooves in which pass the tendons of the
+posterior and external muscles which, belonging to this region, are
+directed for insertion towards the hand.
+
+In animals, because of the movement of rotation of the radius, the
+surface of this bone, which is anterior, corresponds to the posterior
+surface of the same in man. (To possess a clear conception of this, it
+is necessary to remember that, in this latter, the bones of the forearm
+are always described as in the position of supination; they are thus
+represented in Fig. 28. The direction of the surfaces of the radius is
+the reverse of that in animals, since the latter have the radius always
+in a state of pronation.)
+
+Consequently it is on the anterior surface of the bone that we find the
+grooves concerning which it is necessary to give some details. Regarding
+them in passing from the radius towards the ulna, those grooves give
+passage to the tendons of the muscles whose names occupy the columns on
+p. 43. The letters which are referred to each serve to define their
+order, and to facilitate reference to Figs. 28, 29, and 30.
+
+[Illustration: FIG. 30.--INFERIOR EXTREMITY OF THE BONE OF THE FOREARM
+OF THE HORSE: LEFT SIDE, ANTERIOR SURFACE.
+
+1, Radius; A, groove for the long abductor and the short extensor of the
+thumb; B, groove for the radials; D, groove for the common extensor of
+the digits; E, groove for the special extensor of the little finger.]
+
+We should mention that the groove E is situated, both in man and in the
+dog, at the level of the inferior radio-ulnar articulation; but that in
+the horse, as the ulna does not exist at that level, the groove is
+situated on the external surface of the inferior extremity of the
+radius. It is necessary to add that, in some horses, the ulna is,
+nevertheless, represented in this region by a tongue-like process of
+bone; and in such cases the groove is situated in front of this process,
+at the level of the line of coalescence, which there represents the
+articulation.
+
+  -----------------------+-----------------------+-----------------------
+           MAN.          |          DOG.         |         HORSE.
+  -----------------------+-----------------------+-----------------------
+  A. Long abductor of the|A. Long abductor of the|A. _Oblique extensor of
+     of the thumb, and   |   thumb and short     |   the metacarpus_, the
+     short extensor of   |   extensor of the     |   homologue of the
+     the  thumb.         |   thumb united as one |   long abductor of the
+                         |   muscle, _the oblique|   thumb and the short
+                         |   extensor of the     |   extensor of the
+                         |   metacarpus_.[11]    |   thumb, united as one
+                         |                       |   muscle.
+                         |                       |
+  B. First and second    |B. The two radials     |B. The radials
+     external radials    |   blended superiorly, |   represented by a
+     (_extensor carpi    |   distinct inferiorly;|   single muscle, _the
+     radialis longior_   |   this is _the        |   anterior extensor of
+     and _brevior_).     |   anterior extensor of|   the metacarpus_.
+                         |   the metacarpus_.    |
+                         |                       |
+  C. Long extensor of the|C. Long extensor of the|C. The long extensor of
+     thumb.              |   thumb and special   |   the thumb and the
+                         |   extensor of the     |   special extensor of
+                         |   index finger united |   the index are
+                         |   superiorly. These   |   absent.
+                         |   muscles pass in the |
+                         |   following groove.   |
+                         |                       |
+  D. Special extensor of |D. Common extensor of  |D. _Anterior extensor
+     the index finger and|   the digits and the  |   of the phalanges_,
+     the common extensor |   two preceding       |   the homologue of the
+     of the fingers.     |   muscles.            |   common extensor of
+                         |                       |   the digits.
+                         |                       |
+  E. Special extensor of |E. _Extensor of the    |E. Lateral extensor of
+     the little finger.  |   third, fourth, and  |   the phalanges, the
+                         |   fifth digits_, or   |   homologue of the
+                         |   _the lateral        |   special extensor of
+                         |   extensor of the     |   the little finger.
+                         |   digits_, the        |
+                         |   homologue of the    |
+                         |   special extensor of |
+                         |   the little finger.  |
+                         |                       |
+  F. The posterior ulnar |There does not exist on the forearm a groove
+     (_extensor carpi    |for the posterior ulnar muscle, or _external
+     ulnaris_).          |flexor of the metacarpus_.
+  -----------------------+-----------------------------------------------
+
+  [11] The words printed in italics are the names used in veterinary
+       anatomy.
+
+It is also useful to note, with reference to the groove F, in which
+passes, in man, the tendon of the posterior ulnar muscle, that, when the
+forearm is in pronation, the radius alone being displaced, we can only
+see this groove on the surface which looks backwards; and that it is
+then separated from the groove which contains the tendon of the special
+extensor of the little finger by an interval equal to the thickness of
+the head of the ulna.[12] When the forearm is supinated, the two grooves
+are found, on the other hand, one beside the other: and the tendons
+which they contain are very naturally in contact.
+
+  [12] Edouard Cuyer, 'Shape of the Region of the Wrist in Supination
+       and Pronation' (_Bulletin de la Societe d'Anthropologie_, Paris,
+       1888).
+
+In birds the forearm is flexed on the arm, and the latter being directed
+downwards and backwards, the former is, consequently, directed upwards
+and forwards. Further, because of the position of the humerus, which, as
+we mentioned on p. 32, has its inferior extremity so turned that the
+surface which is anterior in man becomes external, the radius, instead
+of being outside the ulna, is placed above it. This latter is larger
+than the radius, but its olecranon process is very slightly developed.
+
+
+The Hand
+
+The hand in animals, as in man, is formed of three parts--the carpus,
+metacarpus, and fingers. In man, the forearm and the hand being
+described in the position of supination; the bones of the carpus are
+named in passing from the most external to the most internal--that is to
+say, from that which corresponds to the radial side of the forearm to
+that which corresponds to the ulnar side. In animals in which, as we
+know, but it is not unprofitable to repeat, the hand is in pronation,
+the radial side of the forearm being placed inside, we enumerate the
+carpal bones in counting the most internal as the first; this is the
+only method which permits us, in taking our point of departure from the
+human skeleton as our standard, to recognise the homologies of the bones
+of the carpal region.
+
+These bones, eight in number, are arranged in two transverse rows, of
+which one, the first, is superior or antibrachial; the other, the
+second, is inferior or metacarpal. Each of these rows contains four
+bones. Considered in the order we have indicated above--that is to say,
+proceeding from the radial to the ulnar side--they are thus named:
+scaphoid, semilunar, cuneiform, and pisiform, in the first row;
+trapezium, trapezoid, os magnum, and unciform, in the second. The number
+of these bones is not the same in all animals on account of the
+coalescence or absence of some. In each row the bones are placed side by
+side, with the exception of the pisiform, which being placed on the
+palmar surface of the cuneiform, produces a small projection in man, but
+a very pronounced one in quadrupeds.
+
+The pisiform is called the _hooked bone_ in some veterinary anatomies.
+If we consider the hook which it forms, we may recognise that the name
+is appropriate; but from the point of view of comparison with the human
+carpus, the name is unfortunate, for it creates confusion between the
+true pisiform (the fourth bone in the upper row), and the last bone in
+the lower row, which is the veritable unciform bone. We do not here seek
+for similarity of form, but homology of regions; and it is only by using
+the same names to denote the same things that we can succeed in
+determining such homology.
+
+Taken as a whole, the bones of the carpus form a mass which, by its
+superior border, articulates with the bones of the forearm, and by its
+inferior border is in relation with the metacarpal region. Its dorsal
+surface (anterior in quadrupeds) is slightly convex; its palmar surface
+(posterior in quadrupeds) is excavated, and forms a groove in which pass
+the tendons of the flexors of the fingers. This last, in man, has the
+appearance of a gutter, because of the prominences caused by the
+projection of the internal and external bones beyond their fellows.
+
+In quadrupeds the palmar groove is especially determined by the pisiform
+bone, of which we have just mentioned the great development.
+
+The region occupied by the carpus, in the unguligrades, is known as the
+_knee_; it would have been more appropriately named had it been called
+the _wrist_.
+
+The number of the metacarpal bones in mammals never exceeds five, but it
+often falls below it; the same is true for the digits. The first are
+generally equal in number to the latter; an exception is met with in
+ruminants, whose two metacarpals coalescing soon after birth, form but
+one bone; this, the _canon_ bone, articulates with two digits.
+
+The number of metacarpals and digits diminishes in proportion as the
+limbs cease to be organs of prehension, and become more exclusively
+organs of support and locomotion.
+
+The number of phalanges is two for the thumb and three for each of the
+other digits; except in the cetaceans, in which they are more numerous.
+
+In the bat, the metacarpals and phalanges are very long, and form the
+skeleton of the wing; these phalanges are not furnished with nails; the
+thumb, which is very short, is alone provided with one (Fig. 8).
+
+With regard to the relative dimensions of the bones of the metacarpus,
+it is necessary to remember that, in the human being, the second
+metacarpal is the longest; then, in the order of decrease, come the
+third, fourth, fifth, and first. In quadrupeds we shall also find
+differences in length (see the chapter relating to the anterior limbs in
+certain animals), but the order of decrease is not always that which we
+have just mentioned.
+
+In man the articular surface, situated at the inferior extremity of each
+of the metacarpals, is rounded, and is called the head. This allows the
+first phalanx, which is in relation with that surface, to be displaced
+in every direction; indeed, this phalanx can not only be flexed and
+extended, but it can also be moved laterally; this latter movement
+allows of the fingers being separated and drawn together.
+
+In quadrupeds which can only perform the movements of flexion and
+extension of the digits--for example, the horse--the inferior extremity
+of the metacarpal has not a rounded head of a regular outline; it is
+marked by a prominent median crest, directed from before backwards, so
+that the articular surfaces, which fit more exactly, form a sort of
+hinge which allows of backward and forward movements only, and permits
+no lateral displacement. In man, at the level of the inferior extremity
+of the first metacarpal, in the vicinity of the articulation of this
+bone with the first phalanx of the thumb, we find two sesamoid
+bones--small bones developed in the fibrous tissue which surrounds the
+articulation. We also meet with such structures, but more rarely, at the
+level of the corresponding articulation of the index and auricular
+digits; and, more rarely still, at those of the middle and ring fingers.
+In quadrupeds, these bones are normally developed, and we shall see
+afterwards that in some animals, as they reach a considerable size, they
+are able to influence the external outlines; we shall see this, for
+example, in the horse.
+
+The hand, in birds, is directed obliquely downwards and backwards (Fig.
+31). For the better understanding of its position in relation to the
+forearm, we should remember that this latter, as we have described (p.
+44), directed obliquely upwards and forwards, has the radius placed
+above the ulna; the hand being oblique in the opposite direction and
+placed under the forearm is, by this arrangement, inclined towards the
+ulnar border of the latter.
+
+[Illustration: FIG. 31.--SKELETON OF THE SUPERIOR LIMB OF A BIRD
+(VULTURE): LEFT SIDE, EXTERNAL SURFACE.
+
+1, Humerus; 2, radius; 3, ulna; 4, radial bone of the carpus; 5, ulnar
+bone of the carpus; 6, first metacarpal; 7, second metacarpal; 8, third
+metacarpal; 9, first digit, the homologue of the thumb; 10, first
+phalanx of the second digit; 11, second phalanx of the second digit; 12,
+third digit.]
+
+For the rest, in order to be able to distinguish readily the
+corresponding parts in the hand of a bird and that of a man, we merely
+have to place the human forearm obliquely, in a direction upwards and
+forwards (Fig. 32), the radius being above; this position we can obtain
+by semi-pronation; then, to incline strongly the hand downwards and
+backwards, moving the ulnar border of the hand towards the ulna; the
+thumb is then anterior, the little finger posterior, and the palm of the
+hand is turned towards the trunk.
+
+The carpus in birds is formed by two bones only, with which the skeleton
+of the forearm articulates. That which is in contact with the radius is
+called the _radial bone of the carpus_; and that with which the ulna
+articulates is named the _ulnar bone_.
+
+[Illustration: FIG. 32.--SUPERIOR LIMB OF THE HUMAN BEING, THE DIFFERENT
+SEGMENTS BEING PLACED IN THE ATTITUDE WHICH THE CORRESPONDING PARTS
+OCCUPY IN BIRDS: LEFT SIDE, EXTERNAL SURFACE.]
+
+The metacarpus is formed of three bones; the first, which is very short,
+is fused at its superior extremity with the adjoining one; this latter
+and the third, both longer than the first, but of unequal size, are
+fused at their extremities. The metacarpal, which articulates with the
+radial bone of the carpus, is larger than the one which is in line with
+the ulna. To the metacarpus succeed three digits, of which the central
+is the longest, and is formed of two phalanges; the other two are formed
+each by a small, stylet-shaped bone. The middle finger, situated on the
+prolongation of the metacarpal, which articulates with the radial bone
+of the carpus, has its first phalanx large and flattened transversely;
+this phalanx seems to have been formed by the union of two bones of
+unequal development; the second phalanx is styloid in form. As to the
+other two fingers, they are placed, one in front and the other behind;
+the first, which articulates with the short metacarpal, fused at its
+upper end with the principal bone of the metacarpus, in position
+represents the thumb. The other, which is the third finger, articulates
+with the inferior extremity of the thinnest bone of the metacarpus; it
+is sometimes closely united to the corresponding border of the first
+phalanx of the large--that is to say, of the median--digit.
+
+
+The Anterior Limbs in Certain Animals
+
+=Plantigrades=: =Bear= (Fig. 33).--The scapula of the bear approaches in
+shape to a trapezium, of which the angles have been rounded off. The
+anterior border (cervical) is strongly convex in the part next the
+glenoid cavity. The junction of the superior (spinal) and the cervical
+border forms almost a right angle, the summit of which corresponds to
+the origin of the spine. At its posterior angle there is a prominence,
+directed downwards, the surface of which is hollowed and is separated
+from the infraspinous fossa by a crest, so that at this level a third
+fossa is added to the infraspinous one. The neck of the scapula is but
+slightly marked. The acromion is prominent, and projects a little beyond
+the glenoid cavity.
+
+The clavicle is rudimentary, but, as an example of the complete
+development of this bone in plantigrade quadrupeds, we may cite the
+marmoset.
+
+The humerus is furnished at its superior extremity with a large
+tuberosity, wide, and situated in front of the head of the bone; the
+effect of this is that the bicipital groove is internal. As in man, the
+great tuberosity does not reach so high as the humeral head, but it
+approaches more nearly to that level. The deltoid impression is very
+extensive, and descends pretty far down on the body of the bone. The
+epitrochlea is prominent; the epicondyle is surmounted by a well-marked
+crest, curved and flexuous in outline.
+
+[Illustration: FIG. 33.--SKELETON OF THE BEAR: LEFT LATERAL SURFACE.
+
+1. Cranium; 2, face; 3, atlas; 4, axis; 5, seventh cervical vertebra; 6,
+first dorsal vertebra; 7, fourteenth and last dorsal vertebra; 8, lumbar
+vertebrae; 9, sacrum; 10, coccygeal vertebrae; 11, sternum; 12, ninth and
+last sternal rib; 13, costal cartilages; 14, acromion process; 15, third
+fossa on the external surface of the scapula; 16, great tuberosity of
+the humerus; 17, musculo-spiral groove; 18, epicondyle; 19, radius; 20,
+ulna; 21, olecranon process; 22, carpus; 23, pisiform; 24, metacarpus;
+25, phalanges; 26, ilium, external fossa; 27, pubis; 28, tuberosity of
+the ischium; 29, obturator foramen; 30, great trochanter of the femur;
+31, condyles of the femur; 32, patella, or knee-cap; 33, anterior
+tuberosity of the tibia; 34, fibula; 35, tarsus; 36, calcaneum, or
+heel-bone; 37, metatarsus; 38, phalanges.]
+
+The articular surface, which is in contact with the radius, is not a
+regularly formed condyle; it is a little flattened on its anterior
+surface, and presents at this level a slight depression which
+corresponds to a small eminence on the anterior aspect of the superior
+extremity of the radius. The surface which articulates with the ulna,
+viewed on its anterior aspect, has the shape of a slightly-marked
+trochlea; except at the level of the internal lip, which, as in man,
+descends lower than the surface for articulation with the radius
+(condyle). Behind, the trochlea is more clearly defined.
+
+The bear possesses a considerable power of rotation of the radius; the
+bones of the forearm are joined only at their extremities, while in the
+remainder of their extent they are widely separated. The ulna terminates
+below in a head and a styloid process; these articulate with the two
+last bones of the first row of the carpus--viz., the cuneiform and
+pisiform. The bones of the carpus are seven in number, the scaphoid and
+the semilunar being fused together.
+
+The metacarpals, five in number, differ very little from one another in
+regard to length, though they increase in size from the first to the
+fifth; this may be demonstrated by looking at the palmar surface of the
+hand. It is the reverse of that which we find in man, for the fifth
+metacarpal is the thickest of all, and the first is the most slender.
+
+At the level of each metacarpo-phalangeal articulation are two sesamoid
+bones.
+
+The third digit is the longest. The terminal phalanges present two very
+different portions: one, the anterior, is curved and pointed; it serves
+to support the nail, whose shape it assumes; the other, posterior, forms
+a sort of sheath into which the base of the nail is received.
+
+The inferior portion of the posterior surface of this latter part
+articulates with the second phalanx in the case of each of the last four
+digits, but with the first phalanx in the case of the thumb.
+
+[Illustration: FIG. 34.--SKELETON OF THE DOG: LEFT LATERAL SURFACE.
+
+1, Cranium; 2, face; 3, atlas; 4, axis; 5, seventh cervical vertebra; 6,
+thirteenth and last dorsal vertebra; 7, lumbar vertebrae; 8, sacrum; 9,
+coccygeal vertebrae; 10, anterior extremity of the sternum; 11, xiphoid
+appendix; 12, ninth and last sternal rib; 13, costal cartilages; 14,
+spinal border of the scapula; 15, supraspinous fossa of the scapula; 16,
+infraspinous fossa of the scapula; 17, great tuberosity of the humerus;
+18, deltoid impression; 19, musculo-spiral groove; 20, olecranon
+process; 21, radius; 22, carpus; 23, pisiform; 24, metacarpus; 25,
+sesamoid bones; 26, phalanges; 27, ilium, iliac crest; 28, pubis; 29,
+tuberosity of the ischium; 30, great trochanter of the femur; 31,
+patella, or knee-cap; 32, anterior tuberosity of the tibia; 33, fibula;
+34, tarsus; 35, calcaneum, or heel-bone; 36, metatarsus; 37, sesamoid
+bones; 38, phalanges.]
+
+[Illustration: FIG. 35.--SCAPULA OF THE DOG: LEFT SIDE, EXTERNAL
+SURFACE.
+
+1, Posterior or axillary border; 2, superior or spinal border; 3,
+anterior or cervical border; 4, spine of scapula; 5, coracoid process;
+AA', length of spinal border.]
+
+[Illustration: FIG. 36.--LEFT SCAPULA OF THE CAT: EXTERNAL SURFACE.
+
+1, Posterior or axillary border; 2, superior or spinal border; 3,
+anterior or cervical border; 4, spine of the scapula; 5, coracoid
+process; AA', length of the spinal border.]
+
+=Digitigrades=: =Cat=, =Dog= (Fig. 34).--In these animals the anterior
+(cervical) border of the scapula is convex; the posterior (axillary)
+border is straight or slightly concave. The supraspinous and
+infraspinous fossae are of equal extent (Figs. 35 and 36). The neck is
+short. The spine of the scapula becomes more and more prominent towards
+its inferior extremity, where it ends in a twisted and inflexed portion,
+which represents the acromion process; this process terminates at the
+level of the glenoid cavity. The coracoid process is represented by a
+small tubercle, slightly curved inwards; this tubercle is situated
+above the glenoid cavity, at the inferior part of the cervical border.
+
+In the dog, the posterior angle, formed by the junction of the axillary
+and the superior (spinal) borders, is obtuse; the spine rises
+perpendicularly from the surface of the bone. The width of the scapula,
+measured at the level of the spinal border (from A to A', Fig. 35),
+equals about half the length of the spine. We must, however, make an
+exception for the turnspit dog, in which the superior border equals
+three-fourths of that length. The scapula is, in this case, of a more
+compact type; it is broader, but shorter. In the cat, the anterior
+outline of the scapula, formed by the union of the cervical border and
+the corresponding half of the spinal, is more convex; the posterior
+angle is not obtuse, as in the dog. The spine is bent slightly downwards
+and backwards; before terminating in the acromion process it presents a
+triangular projection, the apex of which is directed downwards. The
+tubercle which represents the coracoid process is curved inwards more
+strongly than that of the dog, thus resembling more closely the
+appearance of this process in the human being.
+
+All proportions considered, the scapula of the cat is broader than that
+of the dog; its width, measured along the length of its spinal border
+(from A to A', Fig. 36), equals three-fourths of the length of the
+spine.
+
+The clavicle is rudimentary; it is, however, better developed in the cat
+than in the dog. The clavicle of the cat is represented by a small,
+elongated bone, curved in outline, the convexity being turned forward;
+it is united to the acromion and the sternum by ligamentous fibres; that
+of the dog is merely a scale-like osseous plate situated on the
+posterior surface of a muscle of this region (see Figs. 16 and 17).
+
+The humerus is long and twisted in the shape of an S. The inferior
+articular surface has the form of a simple pulley, for the condyle is
+very slightly marked. The internal part of this articular surface
+descends lower than the external; this condition resembles that found in
+the human being, where the inner lip of the trochlea is lower than the
+condyle.
+
+In the dog, the olecranon fossa communicates with the coronoid by an
+opening.
+
+In the cat, there is a supra-epitrochlear canal (see Fig. 19), but no
+olecranon perforation.
+
+The bones of the forearm articulate at their extremities. The body of
+the radius is united to the body of the ulna by a short, thick,
+interosseous ligament; the fibres of this ligament, though short, do not
+prevent the production of some movements at the articulations of the
+bones.
+
+The radius so crosses the ulna that above, it is in front and external
+to the latter, while below, it is internal. This bone is flattened from
+front to back, and slightly convex anteriorly. Its superior extremity is
+formed, externally, of a portion which represents the head of the radius
+in man; internally, by another portion which represents half of the
+coronoid process of the ulna, which, in the human being, belongs
+exclusively to the latter (see p. 39, the encroachment of the radius on
+the ulna). This extremity is surrounded with a vertical articular
+surface which is placed in contact with a small cavity which is hollowed
+out on the ulna (the lesser sigmoid cavity); and presents at its
+superior aspect a surface which articulates with the inferior extremity
+of the humerus. The shaft of the bone has on its internal border
+rugosities analogous to the imprint of the pronator radii teres of the
+human skeleton; these rugosities, indeed, give insertion to a muscle of
+the same function, and bearing the same name. The inferior extremity,
+broader than the superior, is hollowed on its external aspect by a small
+cavity which receives the inferior extremity of the ulna; its inferior
+surface (concave) articulates with the carpus; its anterior surface (the
+homologue of the posterior surface of the corresponding extremity of the
+human radius) presents grooves which serve for the passage of the
+tendons of the muscles which pass from the forearm to the back of the
+hand. (For the names of the muscles whose tendons pass in these grooves,
+see Fig. 29.)
+
+The ulna is furnished at its superior extremity with an olecranon
+process, which is more prominent than that of the human ulna; this
+process is compressed laterally, and its internal surface is hollowed;
+there we also find a great sigmoid cavity, and a coronoid process
+situated at the internal part of the anterior surface, a process which,
+as we have previously shown, it shares with the radius.
+
+The shaft of the bone, prismatic and triangular, diminishes in thickness
+as it approaches the lower extremity, which articulates with the
+corresponding extremity of the radius. In the dog, the ulna terminates
+inferiorly in a blunt point, without enlargement, analogous to the head
+of the human ulna; in the cat, by a head which is prolonged into a
+styloid process, by which it articulates with a portion of the carpus.
+
+The carpus consists of seven bones--three in the superior row and four
+in the inferior. In the superior row the scaphoid and semilunar bones
+are fused together. The pisiform is elongated and expanded at its two
+extremities; it forms a prominence which, directed backwards, projects
+beyond the level of the other bones of this region.
+
+The metacarpal bones are five in number; they are enumerated from within
+outwards; they articulate with the carpus and with each other. The
+inferior extremity of each metacarpal bone presents the form of a
+condyle in front; and is divided behind so as to form two lateral
+condyles, which are separated by a median crest; on these posterior
+condyles are applied two small sesamoid bones. The metacarpal bone of
+the thumb is very short; the third and fourth are the longest. The
+metacarpus, as a whole, is directed vertically.
+
+The phalanges are three in number for each finger, except the thumb,
+which has but two. The first phalanx, directed almost horizontally
+forwards, is the longest; the second is directed downwards and forwards;
+the third consists of two portions: a posterior part, which forms a sort
+of sheath into which the base of the nail is received; and an anterior,
+conical in form, and curved in crochet shape, which forms a support for
+the nail (Fig. 37).
+
+The third and fourth digits are the longest; the second and fifth are of
+equal length; the thumb is the shortest; it does not touch the ground,
+and does not even reach the articulation of the metacarpal bone and
+first phalanx of the second finger.
+
+In the cat, the metacarpal bone of the thumb, although shorter than any
+of the others, is quite as thick. The third digit is a little longer
+than either the second or fourth. In animals of this genus, the claws,
+in the condition of repose, are retracted, and removed from the ground;
+this prevents their being worn, and thus preserves their sharpness. At
+such times the third phalanx is received into a groove which is found on
+the external surface of the second phalanx. In the dog, the claws are
+not tractile.
+
+[Illustration: FIG. 37.--SKELETON OF THE FINGER OF A FELIDE (LION): LEFT
+SIDE, INTERNAL SURFACE.
+
+1, Metacarpus; 2, sesamoid bones; 3, first phalanx; 4, second phalanx;
+5, third phalanx; 6, gutter for the reception of the base of the nail;
+7, prominent osseous crest formed to lodge in the concavity of the
+nail.]
+
+[Illustration: FIG. 38.--SKELETON OF THE PIG: LEFT LATERAL SURFACE.
+
+1, Cranium; 2, face; 3, atlas; 4, axis; 5, seventh cervical vertebra; 6,
+first dorsal vertebra; 7, fourteenth and last dorsal vertebra; 8, lumbar
+vertebrae; 9, sacrum; 10, coccygeal vertebrae; 11, anterior extremity of
+the sternum; 12, xiphoid appendix; 13, seventh and last sternal rib; 14,
+costal cartilage; 15, cartilage of prolongation of the scapula; 16,
+great tuberosity of the humerus; 17, olecranon process; 18, radius; 19,
+ulna; 20, pisiform; 21, metacarpus; 22, phalanges of the two great toes;
+23, phalanges of the external toe; 24, ilium; 25, pubis; 26, tuberosity
+of the ischium; 27, great trochanter; 28, knee-cap; 29, anterior
+tuberosity of the tibia; 30, fibula; 31, tarsus; 32, calcaneum; 33,
+metatarsus; 34, phalanges of the two great toes; 35, phalanges of the
+external toe.]
+
+=Unguligrades=: =Pig= (Fig. 38).--The scapula is markedly narrowed in
+the region above the glenoid cavity. The spine is atrophied at both its
+extremities, so that at its inferior part we do not find the acromion
+process. In its middle portion the spine is prominent, and presents a
+triangular process which turns backwards, overlapping a part of the
+infraspinous fossa; this latter is much larger than the supraspinous.
+The spinal border is surmounted by the cartilage of prolongation, the
+superior margin of which is convex; this cartilage extends posteriorly
+beyond the posterior (axillary) border of the bone.
+
+The small tuberosity of the superior extremity of the humerus is but
+slightly developed; the great tuberosity, on the contrary, is very
+large. The bicipital groove is situated internal to this. The deltoid
+impression is scarcely marked.
+
+The forearm is short, directed obliquely downwards and inwards, thus
+forming with the hand an angle, of which the apex is directed inwards.
+The two bones of the forearm are strongly bound to one another by an
+interosseous ligament, which is formed of very short fibres. The radius
+appropriates, at its superior extremity, the coronoid process of the
+ulna. The latter is, notwithstanding, well developed in the rest of its
+extent; it has a flattened shaft which almost completely overlaps the
+posterior surface of the radius; its inferior extremity reaches to the
+carpus.
+
+The carpus is formed of eight bones--four in the superior row, and four
+in the inferior. The third bone of the superior row (cuneiform) is more
+in contact with the ulna than with the radius.
+
+There are but four metacarpal bones; there is no metacarpal of the
+thumb. The two median metacarpal bones are the longest; they are those
+which correspond to the digits which alone touch the ground. The
+internal digit and the external one are thin and short; they are
+functionless, as a rule, taking no part in supporting the limbs on the
+ground. Notwithstanding this, they are formed, as the other digits, of a
+number of phalanges, which give them the semblance of perfect digits.
+(We shall soon see that in certain animals there exist digits which,
+being incomplete with regard to the numbers of their constituent bones,
+more accurately merit the name of imperfect digits.)
+
+The third phalanges are each enclosed in a horny hoof, to which the name
+of _onglon_ has been given.
+
+We have already drawn attention to the smaller lateral digits, and
+noted the general fact that they do not come in contact with the ground.
+It is necessary to modify this statement by adding that under certain
+conditions they give a slight amount of support; for example, when the
+individual is the subject of excessive obesity, the limbs yield under
+the weight, and the nails of the lateral digits may touch the ground.
+
+A similar fact may be noticed in pigs of ordinary bulk at the moment
+when, during walking, each of the fore-limbs commences to bear the
+weight--that is to say, when it is directed obliquely downwards and
+forwards; then all the digits are in contact with the ground.
+
+=Unguligrades (Ungulates)=: =Sheep=, =Ox= (Fig. 39).--The scapula, which
+is of elongated form, is very narrow in the vicinity of the glenoid
+cavity. The spine, which becomes more and more salient towards its
+inferior part, terminates abruptly in a border, which, forming an acute
+angle with the crest, produces a projection which represents the
+acromion process--a very rudimentary acromion, for it does not reach the
+level of the glenoid cavity. The supraspinous fossa is much smaller than
+the infraspinous; it hardly equals one-third the extent of the latter.
+The anterior border, thin and convex in its superior portion, is concave
+in the rest of its extent; the posterior border is thick and slightly
+concave; the spinal border is surmounted by the cartilage of
+prolongation. In the ox the spine of the scapula, in its middle portion,
+is flexed a little backwards on the infraspinous fossa.
+
+[Illustration: FIG. 39.--SKELETON OF THE OX: LEFT LATERAL SURFACE.
+
+1, Cranium; 2, face; 3, atlas; 4, axis; 5, seventh cervical vertebra; 6,
+first dorsal vertebra; 7, thirteenth and last dorsal vertebra; 8, lumbar
+vertebrae; 9, sacrum; 10, coccygeal vertebrae; 11, sternum; 12, xiphoid
+appendix; 13, eighth and last sternal rib; 14, costal cartilages; 15,
+spine of scapula; 16, cartilage of prolongation of the scapula; 17,
+great tuberosity of the humerus; 18, musculo-spiral groove; 19,
+olecranon process; 20, radius; 21, carpus; 22, pisiform; 23, metacarpus;
+24, rudimentary metacarpal; 25, sesamoid bones; 26, first phalanges; 27,
+second phalanges; 28, third phalanges; 29, anterior iliac spine; 30,
+pubis; 31, tuberosity of the ischium; 32, great trochanter; 33,
+supracondyloid fossa of the femur; 34, patella, or knee-cap; 35,
+anterior tuberosity of the tibia; 36, fibula; 37, coronoid tarsal bone;
+38, tarsus; 39, calcaneum; 40, metatarsus; 41, rudimentary metatarsus;
+42, sesamoid bones; 43, first phalanges; 44, second phalanges; 45, third
+phalanges.]
+
+The great tuberosity of the humerus is highly developed; its summit,
+very prominent, is flexed over the bicipital groove; a prominence of the
+small tuberosity also bends over the groove, with the result that at
+this level the latter is converted into a sort of canal. At the inferior
+extremity the condyle, although not large, is recognisable; for it is
+separated from the trochlea by a depression in form of a groove. In
+contrast to the condition found in man, the condyle descends to a level
+a little below that of the internal lip of the trochlea. (For the
+arrangement of the epicondyle and the epitrochlea, see p. 30.) In the
+sheep, the deltoid impression is but slightly marked; in the ox, it is
+more evident.
+
+The forearm is directed obliquely downwards and inwards, so as to form,
+with the hand, an angle of which the apex is internal; this angular
+outline of the _knee_ (wrist) is so characteristic of ruminants that the
+corresponding region of the horse, when salient inwards, receives the
+name of _ox-knee_. The radius bears the coronoid process, and the larger
+part of the articular surface which comes in contact with the inferior
+extremity of the humerus; the condyle and the trochlea articulate with
+the radius in front; while behind, the trochlea articulates with that
+part of the sigmoid cavity which belongs to the ulna. The posterior
+surface of the shaft of the radius is flattened; its anterior surface is
+slightly convex. The inferior extremity articulates with the carpus by a
+surface which is directed obliquely downwards and inwards. The shaft of
+the ulna is very slender, and fused in its middle third with the body of
+the radius; it terminates below, at the level of the external part of
+the inferior extremity of the radius, by a slightly expanded portion
+which, fused with this latter, forms the articular surface for the
+carpal bones.
+
+In the ox the forearm is short; in the sheep it is proportionally
+longer.
+
+The bones of the carpus are six in number--four in the upper row, and
+two in the lower; they form an irregular cuboid mass which contributes
+to the formation of the region known as _the knee_ in ruminants, as in
+the horse; we have already remarked that the name 'wrist' would be more
+accurate. The anterior surface in its foremost part is vertical, and is
+slightly convex from side to side. At its posterior and external part
+the pisiform bone forms a prominence.
+
+The metacarpus consists of two bones only--one, well developed, which is
+known as the principal metacarpal, or the _canon_ bone (this is the name
+given to the region in the hoofed animals); and a rudimentary one, which
+is situated at the superior and external aspect of the preceding
+metacarpal. Sometimes there is found a third metacarpal at the internal
+aspect; but, when present, it is but very slightly developed.
+
+The principal metacarpal consists of two metacarpals fused together; on
+this account the bone is longitudinally marked in the median line by a
+slight depression which marks the junction of the two bones of which it
+is formed. In some ruminants (certain species of chevrotains) the
+coalescence does not take place, and the two metacarpals remain
+separate.
+
+The anterior surface of the principal metacarpal is convex transversely;
+its posterior surface is flattened. The superior extremity of this bone
+articulates by two facets with the two bones of the inferior row of the
+carpus; on the internal part of the anterior surface of this extremity
+is found a tubercle. The inferior extremity is divided into two parts by
+a fissure or notch; each part is articular, and consists of two separate
+condyles, which are separated from each other by an antero-posterior
+crest; on each side of this crest, and behind, are found two sesamoid
+bones. As for the external rudimentary metacarpal bone, it is nothing
+more than a small, short tongue of bone; which, in goats and sheep, is
+often absent.
+
+The division of the inferior extremity of the principal metacarpal into
+two parts is correlated with the two perfect digits which give the foot
+of the ruminant its forked appearance. Each digit consists of three
+phalanges, which are directed obliquely downwards and forwards; further,
+these phalanges are inclined a little outwards from the axis of the
+limb, so that the two digits diverge from each other as they descend.
+
+The first phalanx, which is the longest, articulates superiorly with the
+principal metacarpal; its inferior extremity terminates in a trochlea,
+and the lip of this, which is situated towards the axis of the limb,
+descends lower than that of the opposite side; this arrangement is
+correlated with the divergent direction of the digits. The second
+phalanx has its superior extremity moulded on the trochlea which
+terminates the extremity of the first; its inferior extremity is
+articular, and elongated from before backwards. On the posterior
+surface of this extremity is found a sesamoid bone.
+
+With regard to the third phalanx, it presents the form of a triangular
+pyramid, and displays a postero-superior concave surface with which the
+second phalanx articulates; an anterior, convex surface, which
+terminates in a point on its anterior part; and an internal surface,
+which is flattened. The third phalanx of each digit is contained in a
+hoof (_onglon_).
+
+There is also found in ruminants two imperfect rudimentary digits, which
+are represented by two small bones situated behind the articulation of
+the metacarpal and the digits which we have just been studying. These
+rudimentary digits are each enveloped in a layer of horn; they
+constitute the _spurs_. The two digits of the ruminants represent the
+third and fourth fingers of the human hand; the two lateral digits,
+greatly atrophied, are the homologues of the second and fifth fingers;
+the thumb is not present.
+
+It is the same as regards the metacarpal bones, which form, by their
+union, the principal metacarpal; the external represents the fourth
+metacarpal, and the internal the third. It is to the latter that the
+tubercle, of which we have already made mention, belongs; and with the
+signification of which, because it gives attachment to a muscle, we
+shall concern ourselves in the section on myology (see Radial Muscles).
+
+=Unguligrades=: =Horse= (Fig. 40).--The scapula is narrow, compared with
+that of the animals we have just been considering. The anterior border
+is convex in its superior portion, and concave in its inferior; the
+posterior border is slightly hollowed out. The supraspinous fossa is
+less in extent than the infraspinous; but the difference is less
+than that between the same fossae in the ox and the sheep; in the
+ox, as we have already indicated, the proportion is one-third; in
+the horse, one-half. The spine, which disappears at the extremities,
+is rough and thick in its middle third, there forming a kind of
+tuberosity--_tuberosity of the spine_. Above and in front of the glenoid
+cavity is found a strong process consisting of a rugous base, and a
+summit which is directed inwards. This forms a kind of hook curved
+towards the inside; it represents the coracoid process. The scapula is
+surmounted by the cartilage of prolongation, of which the superior
+border, which is thin and curved, is parallel to the superior border of
+the prominence of the withers; the cartilage forms, consequently, the
+lateral surface of this region. The cartilage of prolongation undergoes
+ossification in old horses. The humerus is short; the bicipital groove,
+situated on the anterior surface of the superior extremity, separates
+the greater tuberosity from the lesser, and is divided into two parts by
+a median ridge; it is this portion of the humerus which forms the
+prominence known as the _point of the shoulder_, or _point of the arm_.
+The deltoid impression well deserves the name of tuberosity which has
+been given to it, for it is very prominent; the musculo-spiral groove is
+very deep.
+
+[Illustration: FIG. 40.--SKELETON OF THE HORSE: LEFT LATERAL SURFACE.
+
+1, Cranium; 2, face; 3, atlas; 4, axis; 5, seventh cervical vertebra; 6,
+first dorsal vertebra; 7, eighteenth and last dorsal vertebra; 8, lumbar
+vertebrae; 9, sacrum; 10, coccygeal vertebrae; 11, sternum; 12, xiphoid
+appendix; 13, eighteenth and last sternal rib; 14, costal cartilage; 15,
+scapula; 16, cartilage of extension; 17, great tuberosity of the
+humerus; 18, deltoid crest; 19, olecranon process; 20, radius; 21,
+carpus; 22, pisiform; 23, principal metacarpal; 24, metacarpal,
+external rudimentary; 25, large sesamoids; 26, first phalanx; 27,
+second phalanx; 28, third phalanx; 29, ilium, showing external iliac
+fossa; 30, pubis; 31, tuberosity of the ischium; 32, great trochanter;
+33, infratrochanteric crest, or third trochanter; 34, supracondyloid
+fossa of the femur; 35, knee-cap; 36, anterior tuberosity of the tibia;
+37, the fibula; 38, tarsus astragalus; 39, calcaneum; 40, principal
+metatarsal; 41, rudimentary external metatarsal; 42, large sesamoids;
+43, first phalanx; 44, second phalanx; 45, third phalanx.
+
+_To face p. 64._]
+
+At the inferior extremity, the trochlea is large; the portion
+corresponding to the condyle of the humerus in man is, in proportion to
+the latter, of small extent. The olecranon fossa is deep. The epicondyle
+and the epitrochlea are somewhat different from those of the human bone.
+In the latter, the epitrochlea is salient towards the inner side,
+causing an increased transverse diameter of the inferior extremity of
+the humerus. In the horse--it is the same in ruminants--this tuberosity
+projects backwards, folds on itself in forming the internal boundary of
+the olecranon cavity, and exceeds in diameter, in the antero-posterior
+direction, the prominence of the epicondyle, which presents a nearly
+similar arrangement. This latter has, however, a part which, projecting
+externally, is situated at the inferior part of a crest, that forms the
+posterior boundary of the musculo-spiral groove. The result is that,
+contrary to the condition found in the human being, the epicondyle is
+more prominent transversely than the epitrochlea, but this latter is
+more salient on the posterior aspect. The epitrochlea and the epicondyle
+offer a larger surface for the origin of muscles of the forearm than the
+same prominences in the human bone do for the analogous muscles of the
+same region.
+
+Some veterinary anatomists have given to the inferior and external
+articular surface of the humerus the name of trochlea; and to the
+internal one, that of condyle. On this account they designate the
+external prominence as the epitrochlea, and the internal one as the
+epicondyle. In addition to the fact that this point of view is not
+legitimate, it produces inevitable confusion when comparing the parts
+with those of the human humerus, and this confusion exists, not alone in
+describing the bone, but also in the description of the muscular
+attachments, and in the comparison of the muscles of the forearm of
+quadrupeds with the corresponding muscles in the human species.
+
+The radius is placed in front of the ulna; its body, slightly convex
+forwards, has the anterior surface convex transversely, and the
+posterior surface plane in the same direction. It is to the external
+part of this latter that the ulna is applied, which is completely fused
+with the radius.
+
+The superior extremity of the radius is a little larger than the
+inferior. Its superior aspect, concavo-convex, moulded on the inferior
+articular surface of the humerus, presents internally two cavities,
+which receive the lips of the trochlea, and, externally, another,
+smaller, cavity, which receives the condyle. The radius articulates with
+the trochlea and the condyle, having appropriated a portion of the ulna,
+as is proved by the presence of the coronoid process, which belongs to
+the former. This superior extremity presents, internally, a tuberosity
+into which the biceps is inserted; this is the bicipital tuberosity; and
+on the other side is another tuberosity, which is a little more
+prominent than the preceding.
+
+The inferior extremity, which is flattened from before backwards, is
+furrowed on its anterior surface by grooves for the passage of muscles
+(the names of the muscles whose tendons pass in these grooves have
+already been given on p. 43). It articulates at the lower end with the
+superior row of the carpus, and it terminates laterally in tuberosities:
+one, external, on which is found a groove for the tendon of the lateral
+extensor of the phalanges, the homologue of the special extensor of the
+little finger; the other, internal, is a little more prominent than the
+one we have just described. These tuberosities are visible under the
+skin which covers the superior and lateral parts of the region known as
+the _knee_; but which, we again repeat, is no other than the wrist.
+
+The ulna has a triangular shaft, situated at the posterior surface of
+the radius, with which it is fused. It disappears completely at the
+level of the inferior third of the forearm. Occasionally, in some
+horses, the ulna is abnormally long, in the form of a slender tongue of
+bone; and extends to the neighbourhood of the external tuberosity of the
+inferior extremity of the radius (see Fig. 79, p. 196). Its superior
+extremity is chiefly represented by the olecranon process, which is
+voluminous in bulk, and forms the projection known as the point of the
+elbow. This process is flattened laterally; its internal surface is
+excavated; the anterior surface, which is concave, forms a part of the
+great sigmoid cavity; the remainder of the cavity is formed by the
+radius.
+
+In the ass, the ulna is a little longer than in the horse--that is to
+say, it descends lower; and the radius is a little more convex
+anteriorly.
+
+The carpal bones are seven in number--four in the superior row, and
+three in the inferior. The trapezium is wanting in the latter.
+Sometimes, however, in certain varieties of horses the trapezium is
+developed, but then it is no more than a very small osseous nodule. The
+pisiform bone, situated at the external part of the first row of bone,
+is prominent posteriorly. It is of rounder form and flattened from
+without inwards. It articulates with the trapezium and the radius. It
+presents, on its external surface, a groove for the passage of the
+tendon of the posterior ulnar muscle, which is named by veterinary
+anatomists the _external flexor of the metacarpus_.
+
+The carpus, as a whole, is of an irregularly cuboid shape; its anterior
+surface, slightly convex from side to side, forms the skeleton of the
+region of the _knee_ (wrist). The metacarpus is formed of three bones:
+the principal metacarpal and the two rudimentary ones.
+
+The principal metacarpal, which forms the region of the _canon_, is
+directed vertically; its anterior surface is slightly convex
+transversely. This surface is covered by a number of tendons, which
+slightly alter its appearance; so that it is the principal base of this
+part of the fore-limb. Its posterior surface is flattened. The superior
+extremity of this metacarpal presents plane surfaces, variously
+inclined, with which the bones of the inferior row of the carpus
+articulate. On the anterior surface, and a little to the inner side, is
+found a tuberosity, which is destined for the insertion of _the anterior
+extensor of the metacarpus_, the homologue of the radial muscles. The
+inferior extremity is formed by two condyles, an internal and an
+external; between which is found a median crest.
+
+This extremity, the superior extremity of the first phalanx, which
+articulates with it, together with two sesamoid bones--the great
+sesamoids--which are situated on its posterior surface, collectively
+form the region which from its rounded outlines is called the _ball_.
+
+With regard to the rudimentary metacarpals, external and internal, to
+which some authors give the name of _fibulae_, they are applied to the
+sides of the posterior surface of the principal metacarpal. They are
+elongated bones, of which the superior extremity, which is a little
+thickened, is called the _head_; the lateral bones of the second row of
+the carpus partly rest on the heads of these. They become more slender
+as they descend, and terminate opposite the inferior fourth of the
+principal metacarpal. Each ends in a slight swelling, to which the name
+_button_ has been given. The internal one is the better developed.
+
+The rudimentary metacarpals are vestiges of atrophied digits, as will be
+explained further on.
+
+The single finger of the horse consists of three phalanges. The first
+phalanx, which is directed obliquely downwards and forwards, corresponds
+to the constricted region situated below the 'ball,' and known as the
+_pastern_. It is flattened from before backwards; its anterior surface
+is convex transversely, while the posterior surface is plane. Its
+superior extremity is moulded on the inferior extremity of the principal
+metacarpal, and its inferior extremity, which is smaller, presents a
+trochlea with which the second phalanx articulates. This is also
+directed downwards and forwards, and is shorter. It corresponds to the
+region which, situated between the pastern and the hoof, is known as the
+_cornet_.
+
+The third phalanx, situated entirely within the hoof, has the same
+direction as the first and second. It is large and broad, and presents
+three surfaces separated by well-marked angular borders (see Fig. 96).
+The anterior surface is oblique downwards and forwards; it is convex
+transversely. The inferior surface is slightly hollowed, and is in
+relation with the sole, or plantar surface of the hoof.
+
+The superior surface, which is articular, is divided by a median ridge
+into two lateral cavities, which correspond to the trochlea on the
+inferior surface of the lower extremity of the second phalanx. The
+inferior border corresponds in shape with the hoof. The superior border
+presents in its median part a projection, _the pyramidal eminence_,
+which prolongs at this level the anterior surface of the bone. Finally,
+the posterior border, which is concave, is in contact with a sesamoid
+bone, _the lesser sesamoid_, which increases the superior articular
+surface behind, and is also in contact with the second phalanx.
+
+As we have just seen, the horse possesses but one digit. In the
+ancestors of the animal--that is, in the prehistoric species which
+are now extinct (_orohippus_, _miohippus_, _protohippus_, or
+_hipparion_)--the number of digits was larger; this fact conclusively
+proves that the rudimentary metacarpals of the existing horse are
+vestiges of digits which have disappeared through want of use. In the
+first of those ancestors--orohippus--there were four digits; all save
+the first, the thumb, being then developed. In the others of the series
+there existed but three digits. It must, however, be noted that in those
+animals it is always the digit which corresponds to the middle finger of
+the pentedactyl hand that is longest. In other less ancient species the
+lateral fingers are reduced to the condition of mere splints of bone. It
+follows from what has been said that the digit which persists in the
+equine species should be considered as the third finger, and that the
+rudimentary metacarpals represent lateral digits considerably
+atrophied.
+
+This disappearance of the lateral digits cannot excite surprise when we
+consider the functions of the organs. Becoming useless, they must
+undergo gradual atrophy from want of use.
+
+There undoubtedly is, in this former existence of supplementary digits
+in the horse, something analogous to what we still find in the pig;
+where the two principal digits are accompanied by two shorter ones,
+which very probably, from their infrequent use, are destined to
+disappear in a more or less distant future.
+
+
+Proportions of the Arm, the Forearm, and the Metacarpus
+
+As a supplement to the study of the anterior limbs which we have just
+finished, it appears necessary to give some indications of the relative
+proportions of certain of the segments which form these limbs in the
+plantigrades, the digitigrades, and the ungulates.
+
+First, we would remark that, in following this order of classification,
+the scapula becomes less and less narrow, and assumes a form more and
+more elongated. In order to convince ourselves of this, it will be
+sufficient to study the bone first in man, then in the bear, the cat,
+dog, ox, and finally in the horse.
+
+As to the proportions of length, which are those we should chiefly
+study, we shall commence with the comparison of the forearm and
+arm--that is to say, the radius and the humerus. The radius is found to
+be longer in proportion to the humerus, as the number of digits is
+smaller, and the hand loses more and more the functions of an organ of
+prehension. In man, the radius is shorter than the humerus; in the
+horse, on the contrary, it is longer.
+
+To give an idea of this proportion, we shall employ what is known as the
+antibrachial index. This index gives the relation which exists between
+the length of the forearm and that of the humerus; the length of this
+latter, whatever may be the actual measurement, is represented by a
+fixed figure, the number 100. A very simple arithmetical operation
+gives the proportion--
+
+  forearm x 100
+  -------------, the quotient obtained furnishes the index.
+     humerus
+
+The index is less than 100 if the forearm is shorter than the bone of
+the arm. The index is more than 100 if, on the contrary, the forearm is
+longer.
+
+In man, the radius is shorter than the humerus; indeed, in adult
+individuals of the white race the average index is 74.
+
+In the bear, the length of the radius approaches closely to that of the
+humerus; the index is about 90. In the skeleton of a bear in the
+anatomical museum of the Ecole des Beaux-Arts, the humerus is 33
+centimetres in length, and the radius 30 centimetres.
+
+In the cat, the radius is very little shorter than the humerus. In the
+dog they are equal. The antibrachial index of the latter is,
+accordingly, 100.
+
+In the horse, the radius is longer than the humerus; the index is
+therefore above 100. Thus, in the skeleton of the horse which we have in
+the museum of the Ecole des Beaux-Arts, the index is 113--length of
+humerus, 29 centimetres; length of radius, 33 centimetres. In other
+skeletons which we have measured we found: in one, 108--humerus, 34
+centimetres; radius, 37 centimetres; in another, 116--humerus, 25
+centimetres; radius, 29 centimetres.
+
+The metacarpal bone undergoes, relatively to the humerus, a proportional
+elongation, analogous to that of the forearm.
+
+In man, the length of the metacarpus is contained about 5-1/2 times in
+that of the humerus; in the bear, it is contained 4 times; in the dog,
+2-1/2 times; in the horse, 1-1/3 times only.
+
+It is well known that the proportions vary according to race, and that
+what we have here given are but the general indications.
+
+
+The Articulations of the Anterior Limbs
+
+The knowledge of human arthrology which we presume the reader to have
+previously acquired makes it unnecessary for us to enter into numerous
+details regarding the configuration of the articular osseous surfaces
+and the disposition of the fibrous bands that retain them in position.
+Accordingly, in the description which follows, and also in that of the
+articulations of the posterior limbs, we shall occupy ourselves but very
+briefly with the details above referred to, so as to devote ourselves
+especially to the indication of the movements--that is to say, of that
+which, while easily comprehended on recollection of former studies,
+presents the greatest interest from the artistic standpoint in these
+studies in comparative anatomy.
+
+=The Scapulo-Humeral Articulation.=--The head of the humerus and the
+glenoid cavity of the scapula being in contact, the two bones are bound
+together by a rather loose articular capsule, which is strengthened by
+the muscles of this region which fulfil the function of active
+ligaments.
+
+This articulation, so movable in every direction in the human species,
+is not so much so in quadrupeds; the arm in the latter, as also the
+shoulder, being kept in contact with the lateral region of the thorax by
+the numerous muscles which surround it.
+
+Of the movements performed by the humerus, flexion and extension are the
+most extensive; those of abduction and adduction are much less so.
+
+It is necessary, before proceeding further, to determine what the two
+principal movements which we have just mentioned really are, viz.,
+flexion and extension.
+
+We know that in man the displacements of the humerus which take place in
+the antero-posterior direction are known as movement or projection
+forwards, and movement or projection backwards, respectively. We do not
+say that the humerus is flexed or extended, because, in reality, on
+account of the position which the skeleton of the shoulder occupies, it
+is not able to flex or place itself on the line of prolongation of the
+scapula with which it articulates.
+
+In quadrupeds it is not so. The humerus and the scapula are contained in
+almost the same vertical plane; and the bone of the arm can take, in
+relation to the latter, the positions characteristic of flexion and
+extension--that is, of approach to the scapula and removal from it.
+
+What makes the meanings of these terms a little confusing is that, in
+human anatomy, some authors consider the backward movement of the
+humerus as extension, and the forward movement as flexion; in order to
+be able to compare these movements to those that the femur executes in
+relation to the pelvis.
+
+Now, in our opinion, the indication of this correspondence is not
+absolutely necessary; since it ceases to be exact if we wished, from the
+point of view of the direction given to other segments of the skeleton,
+to establish the same relation between the elbow and the articulation of
+the knee.
+
+It is therefore indispensable, when discussing quadrupeds, to
+discontinue these terms, in order the more readily to recognise that: in
+flexion the inferior extremity of the humerus is directed backwards; in
+extension, on the contrary, it is directed forwards. In the first case
+the humerus approaches the scapula; in the second, on the contrary, it
+moves away from it.
+
+These movements, which take place during walking, are executed in the
+following manner: When one of the anterior limbs is at the end of that
+stage of progression which is called support (see p. 289, Displacements
+of the Limbs)--that is to say, during the time that the foot remains in
+contact with the ground, whilst the trunk is moving forward--the
+direction of this limb becomes more and more oblique downwards and
+backwards. At a certain moment the limb is raised from the ground, to be
+carried forwards, in order to be again pressed on the ground, and
+recommence a new resting stage. In these different phases the humerus is
+flexed. But at the moment that the limb, when carried forwards, is about
+to resume its contact with the ground it becomes directed obliquely
+downwards and forwards; then the humerus is in the position of
+extension.
+
+During these movements of the humerus, there exists an essential
+factor--that is, the scapular balance. (It is the same as what occurs in
+man when he balances his arm in the antero-posterior plane.) When the
+humerus is flexed, the scapula moves in such a way that the superior
+portion projects forwards; when it is extended, the scapula, on the
+other hand, is inclined more backwards. But it is necessary to add that,
+during these displacements, the scapulo-humeral angle varies; it tends
+to close during the flexion of the humerus, and becomes more open during
+extension.
+
+The movements and the relations of the humerus and the scapula are
+clearly represented in Figs. 41 and 42, reproduced from the
+chromophotographic studies of Professor Marey--studies relative to the
+analyses of the movements of the horse.[13] They show clearly the
+movements of flexion and extension of the humerus, also the balancing of
+the scapula which accompanies the movements.
+
+  [13] E. J. Marey, 'Analyses of the Movements of the Horse by the
+       Chromophotograph' (_La Nature_, June 11, 1898).
+
+[Illustration: FIG. 41.--FLEXION OF THE HUMERUS: RIGHT ANTERIOR LIMB OF
+THE HORSE, EXTERNAL SURFACE (AFTER A CHROMOPHOTOGRAPHIC STUDY BY
+PROFESSOR MAREY).]
+
+[Illustration: FIG. 42.--EXTENSION OF THE HUMERUS: RIGHT ANTERIOR LIMB
+OF THE HORSE, EXTERNAL SURFACE (AFTER A CHROMOPHOTOGRAPHIC STUDY BY
+PROFESSOR MAREY).]
+
+=The Articulation of the Elbow, or the Humero-ulnar Articulation.=--In
+this articulation, which is constructed in the form of a true hinge, the
+movements of flexion and extension alone are possible. In flexion, the
+forearm, directed forwards, is folded on the arm, with which, in certain
+circumstances, it comes in contact. For example, in a horse of mettle
+which leaps over an elevated obstacle, the animal forcibly raises his
+fore-limbs by flexing them. Flexion is produced to the same extent, and
+even more so, and for a longer period, in felides which crouch.
+
+In extension, on the contrary, the forearm is carried backward. This
+movement being limited only by the contact of the tip of the olecranon
+with the bottom of the olecranon fossa of the humerus, the forearm is
+enabled, in this case, to move until it is in line with the arm. For
+example, during walking, when one of the anterior limbs, having reached
+the end of its resting stage, is considerably inclined downwards and
+backwards.
+
+The apex of the olecranon process--that is to say, the point of the
+elbow--forms a marked prominence, more salient in flexion than in
+extension, as in the corresponding region of the human elbow.
+
+=The Radio-ulnar Articulation.=--It is in the dog and the cat, in which
+the two bones of the forearm articulate by their extremities only, and
+remain separate in the rest of their extent, that the articulations call
+for special notice.
+
+In the upper part, the radius rotates on itself; while below, it rotates
+around the ulna. It follows that the forearm, which in all quadrupeds is
+in a state of permanent pronation, can, in carnivora, take the position
+of supination, or rather, of demi-supination. In fact, whatever be the
+mobility of the two bones of the forearm, the movement is not able to
+bring the palmar surface to the front, but only to direct it towards the
+median line.
+
+=The Articulation of the Wrist.=--Here are found, as in man, three
+superimposed articulations: the radio-carpal, intercarpal, and
+carpo-metacarpal.
+
+If we remember the movements which take place at the plane of these
+articulations in man, and take account of the fact that the mobility of
+the limbs is reduced just in proportion as they are simplified in
+structure so as to become organs of support only, we can easily
+comprehend that, in the horse and the ox, and, in a word, animals that
+have a canon bone, the movements of the wrist are little varied in
+character, while in carnivorae, on the other hand, they are relatively
+more so.
+
+We will remember that in the ox and the horse the region of the wrist is
+called the _knee_.
+
+In flexion, the hand is bent backwards; in extension it is carried
+forwards. These two movements take place especially in the radiocarpal
+and intercarpal articulations. In the first of these articulations, it
+is the superior row of the carpus which glides backwards and forwards on
+the corresponding articular surface of the forearm. In the second
+articulation, it is the second row which moves; gliding on the inferior
+articular surfaces of the row above it. This inferior row carries the
+metacarpus with it; for the carpo-metacarpal articulation is much less
+mobile than either of the other two.
+
+In flexion, the articular surfaces are separated from one another in
+front; and the changes of form which result from this are noticeable on
+the anterior surface of the 'knee.' Moreover, at that moment this region
+contrasts markedly in its outlines with the parts above it and below
+it--that is to say, with the corresponding surfaces of the forearm and
+of the canon bone.
+
+As for the lateral movements, by which the hand is inclined outwards and
+inwards in its movements at the wrist, they exist to an appreciable
+extent in the cat and the dog only; in order to understand this, it is
+enough to compare the shape of the articular surfaces of this region in
+carnivora and the horse, for example. In the latter, those surfaces are
+almost plane; in the cat, on the contrary, they are curved (inferior
+surface of the forearm, concave; superior border of the carpus, convex).
+These latter, then, are, in form, similar to those which exist at the
+same level in the human being; this explains the possibility of
+analogous movements of the whole hand--that is to say, of the movements
+of abduction and adduction.
+
+=The Metacarpo-phalangeal Articulations.=--With regard to the mobility,
+it is in these articulations, as in those of the wrist--that is to say,
+although in all quadrupeds the first phalanges can be flexed and
+extended on the metacarpus, it is only in the cat and dog that lateral
+movement is possible. Indeed, in the horse, in which the principal
+metacarpal terminates inferiorly in two convex surfaces, which are
+separated by a crest; and where the whole articulates with a cavity on
+the superior extremity of the first phalanx; because of the hinging of
+these surfaces, there can only be movements of opening and closing of
+this articulation. The first phalanx is directed backwards during
+flexion and forwards during extension. In the dog and the cat the digits
+can be separated from each other, and also drawn together--that is to
+say, abducted and adducted; but, as in man, these movements can be made
+only when the first phalanges are in the state of extension. During
+flexion they are impossible, because of the tension of the lateral
+ligaments, which increases as the flexion is more pronounced. This can
+be demonstrated, for example, in the cat, which, in order to separate
+the digits, opens the hand widely--that is to say, forcibly raises the
+first phalanges.
+
+=The Interphalangeal Articulations.=--The phalanges are in contact with
+one another by surfaces, which, on one side, are of trochlear form, and,
+on the other, are moulded on these trochleae; accordingly, at the level
+of these articulations, the movements of flexion and extension only can
+take place.
+
+In the felidae, the claws which the third phalanges bear cannot be
+utilized when the latter are in a state of extension, at which time,
+being forcibly raised, they are, in fact, placed on the outer sides of
+the phalanges, which are grooved to receive them. But when the animal
+wishes to use them, it flexes those third phalanges, of which the
+terminal extremity is then projected forward, and the claws are ready to
+fulfil their function. But at the same time it extends the first
+phalanges, to produce a certain tension of the flexors of the digits,
+and thus enable the latter to act with greater efficacy, with a minimum
+of contraction. We can demonstrate this action experimentally on
+ourselves. It is enough to carry the first phalanges forcibly into a
+state of extension; the third phalanges then become flexed, quite
+spontaneously, by the tension of the tendons of the flexors which are
+inserted into them.
+
+At the same time, if we examine the felidae which we have taken as
+examples, when the first phalanges are in the state of extension, the
+digits will be found to be separable, as we have already indicated in
+connection with the metacarpo-phalangeal articulations, with the result
+that the claws are then able to lacerate a wider surface.
+
+The extension of the ungual phalanx, which determines the retraction of
+the claw and stops its action, is the mechanical result of an elastic,
+fibrous apparatus which is attached to each of the third phalanges, and
+has its origin of the second.
+
+
+THE POSTERIOR LIMBS[14]
+
+  [14] Examine Figs. 21, 33, 34, 38, 39, 49.
+
+The posterior limbs are divided, as are the inferior limbs of the human
+being, of which they are the homologues, into four parts: pelvis, thigh,
+leg, and foot.
+
+
+The Pelvis
+
+The pelvis, which incompletely limits the abdominal cavity, inferiorly
+in the vertical position of the body and posteriorly in the normal
+attitude of quadrupeds, is formed by the iliac bones and sacrum--the
+coccyx forming a prolongation of the latter. We have already described
+the two latter (pp. 10 and 11) in connection with the vertebral column,
+of which they form the inferior or posterior portion or segment,
+according to the attitude of the individual.
+
+=The Iliac Bone.=--The iliac or coxal bone, is a paired or
+non-symmetrical bone, united below to its fellow of the opposite side,
+while it is separated from it above by the sacrum.
+
+In all animals, as well as in man, the iliac bone, at the beginning of
+life, consists of three parts, which afterwards unite and fuse together
+and join at the middle of the bottom of a deep cavity which is situated
+on the outer aspect of the bone--the cotyloid cavity.
+
+Of those three portions when examined in the human iliac bone, that
+above the cavity is the ilium; that on the inside is the pubis; and the
+last, the lower one, is the ischium. In quadrupeds, the iliac bone
+being, in its entirety, directed much more obliquely downwards and
+backwards, the relative position of these constituent parts is a little
+modified: the ilium is in front, the pubis is still internal, but in a
+more inferior position, and the ischium is behind the cotyloid cavity.
+We notice this peculiarity of the development of the iliac bone because
+it is customary to continue to apply to the osseous regions which
+correspond to these parts the names by which they were known when
+independent bones.
+
+[Illustration: FIG. 43.--THE LEFT ILIAC BONE OF THE HUMAN BEING:
+EXTERNAL SURFACE, PLACED IN THE POSITION WHICH IT WOULD OCCUPY IN THE
+SKELETON OF A QUADRUPED.
+
+1, Cotyloid cavity; 2, ilium; 3, iliac crest; 4, anterior iliac crest;
+5, posterior iliac spine; 6, pubis; 7, tuberosity of the ischium; 8,
+obturator foramen; 9, ischiadic spine.]
+
+[Illustration: FIG. 44.--LEFT ILIAC BONE OF A QUADRUPED (HORSE):
+EXTERNAL SURFACE.
+
+1, Cotyloid cavity; 2, ilium, external iliac fossa (directed upward in
+the horse); 3, iliac crest; 4, anterior iliac spine (directed inwards in
+the horse, it is the angle of the haunch); 5, posterior iliac spine
+(directed inwards in the horse; it is the angle of the haunch); 6,
+pubis; 7, tuberosity of the ischium; 8, obturator foramen; 9, ischiadic
+spine, or subcotyloid foramen.]
+
+The bones which form the skeleton of the pelvis of quadrupeds are
+proportionally more elongated and less massive than those of the human
+pelvis (Figs. 43 and 44).
+
+We find, on the external surface of the iliac bone, the cotyloid cavity,
+whose border is interrupted by the cotyloid notch; a deep notch which
+looks downwards.
+
+In front of this cavity is the ilium. This portion, narrow in the part
+which is next the cavity, is directed forwards and upwards, expanding
+more and more as it passes upwards. It presents an external or superior
+surface (external in some animals, superior in others), which recalls
+the external iliac fossa; and an internal or inferior surface, at the
+superior part of which is found the auricular surface for articulation
+with the sacrum.
+
+The anterior border of the ilium is rough; this is the iliac crest, at
+the extremities of which we find, below or outside, a prominence which
+corresponds to the anterior superior iliac spine of man; and internally
+another projection which corresponds to the posterior iliac spine.
+
+Immediately above the cotyloid cavity is a rough crest, which is known
+as the _supracotyloid crest_, which is, however, no other than the
+homologue of the sciatic spine. In front of this prominence, the border
+of the ilium, which is notched, forms the great sciatic notch.
+
+If, still taking the cotyloid cavity as the point of departure, we
+proceed inwards--that is, towards the median line of the body--we find
+the pubis; if in a posterior direction, the ischium. These two portions,
+pubis and ischium, limit an oval orifice, the subpubic foramen.
+
+In the human skeleton, the pubis of one side is united to that of the
+opposite side, to form the pubic symphysis. In the animals which we are
+now studying a portion of the ischium enters into the formation of the
+symphysis; in other words, it is formed, not only by the body of the
+pubis, but also by the descending branch or ramus of the pubis and a
+portion of the ascending branch or ramus of the ischium, which are fused
+with those of the opposite side. It results that, though in the human
+being the symphysis is short and the ischio-pubic arch large, in
+quadrupeds it is the opposite. In them the arch is a mere slot, and
+being formed by the ischium alone, merits the name of the ischial arch.
+The ischio-pubic symphysis is very large, and forms a horizontal surface
+relatively extensive, a sort of floor, on which rest certain organs
+which occupy the cavity of the pelvis.
+
+The posterior and external angle of the ischium is rough and prominent;
+it is the tuberosity of the ischium. This forms a projection under the
+skin; it also does in man when the trunk is strongly inclined forwards,
+while the thighs are maintained in the vertical position. In
+marsupials--opossum, kangaroo, and phalanger--the pelvis at its pubic
+region is surmounted by two bones, situated one on each side of the
+median line, and arranged in the form of a fork of two prongs (Fig. 45).
+These, which are called _marsupial bones_, support the pouch which, in
+animals of this genus, lodges their young, which, at the time of birth,
+are incapable of supporting a separate existence, their development
+being absolutely incomplete.
+
+[Illustration: FIG. 45.--PUBIC REGION OF THE PELVIS OF A MARSUPIAL
+(PHALANGER, FOX).
+
+1, Symphysis pubis; 2, obturator foramen; 3, marsupial bones.]
+
+In the cetaceans--for example, the dolphin--because of the absence of
+posterior limbs, the pelvis is represented by two separate bones only,
+which have no connection with the vertebral column. In birds, the pelvis
+is remarkable for its elongated form (see for its form Fig. 21, and for
+details Fig. 46). The cotyloid cavity is pierced by an opening, and
+presents on its posterior border, which is here a little prominent, a
+surface with which the great trochanter is in contact.
+
+The ilium is very highly developed, and is fused in the median line with
+the ilium of the opposite side, the last dorsal vertebrae, the lumbar
+vertebrae, and the sacrum. Because of these relations with the dorsal
+vertebrae, it is in contact anteriorly with the last ribs, which
+consequently emerge from each side of the iliac region of the pelvis.
+
+The ischium forms a plate of bone which, in part, closes the external
+portion of the cavity of the pelvis. Its superior border is separate for
+a certain distance from the external border of the ilium; there is thus
+left an opening of more or less considerable size, which represents or
+takes the place of the great sciatic notch.
+
+[Illustration: FIG. 46.--PELVIS OF A BIRD (THE COCK): EXTERNAL SURFACE,
+LEFT SIDE.
+
+1, Ilium; 2, ischium; 3, pubis; 4, inferior extremity of the pubis; 5,
+sciatic foramen; 6, oval foramen, homologous to the obturator; 7,
+coccygeal vertebrae.]
+
+The pubis, long and slender, is in connection with the inferior border
+of the ischium, of which it follows the general direction; and
+circumscribes with this latter, below the cotyloid cavity, an oval
+orifice, which is the homologue of the obturator foramen. Its inferior
+extremity reaches beyond the corresponding part of the ischium, bending
+towards the middle line, but without joining the pubis of the opposite
+side. On this account there is no symphysis pubis in birds.
+Nevertheless, an exception must be noted in the case of the ostrich, the
+pubic bones of which meet in the middle line, and are articulated in
+form of a symphysis.
+
+
+The Thigh
+
+A single bone, the femur, forms the skeleton of this portion of the
+lower limb.
+
+=The Femur.=--The bone of the thigh is, in man, directed downwards and
+inwards; this obliquity, we may remind the reader, is due to the
+difference in length of the two condyles which form its inferior
+extremity; the internal is the more prominent, the result of which is
+that when the femur is held vertically, the internal condyle descends
+lower than the external. Now, as those two articular expansions rest on
+the horizontal plane formed by the upper extremity of the tibia, it
+follows that the superior part of the femur inclines towards the side of
+the shorter condyle--that is to say, outwards--and that, the leg being
+vertical, it and the bone of the thigh unite in forming an angle, of
+which the apex is directed towards the inner side of the knee.
+
+In many mammals the two condyles are equally prominent, the result of
+which is that the femur inclines neither inwards nor outwards, but is
+contained in a plane parallel to the axis of the trunk; while the leg is
+included in the same plane. Nevertheless, although contained in the
+plane which we have just indicated, the femur is obliquely placed, and
+directed downwards and forwards; it accordingly forms, with the pelvis,
+an angle, of which the opening is directed to the anterior aspect of the
+body.
+
+In reptiles and in birds the femur and leg are both placed in the same
+plane, but this plane is not parallel to the axis of the trunk. This is
+the result, on the one hand, of the thorax being wide, and, on the other
+hand, of the femur, which is directed forwards, being in contact by its
+anterior extremity with the lateral aspect of the costal region, it is
+thus necessarily placed in a direction forwards and outwards, and the
+knee is further removed from the axis of the trunk than is the
+articulation which unites the thigh with the pelvis.
+
+The femur, like the humerus, is almost completely enveloped by muscular
+masses, which bind it to the lateral walls of the abdomen. Its inferior
+extremity alone is free, and is always the more so in proportion to its
+elongation--that is to say, as it belongs to an animal whose foot is
+more divided. The femur in this respect conforms to the law which we
+have indicated in connection with the bone of the arm, in which the
+development, as to length, is in proportion to the division of the hand.
+
+If we compare the femur of certain animals with that of man, we see that
+the corresponding details of form are readily recognisable, but they are
+slightly modified. Thus, on examining the superior extremity, we find
+there a head, a neck, a great trochanter, and a lesser; but the neck is
+usually short and thick, and the great trochanter does not occupy the
+same level with regard to the articular head of the bone. In man, the
+great trochanter does not rise to the level of the head of the femur; in
+the dog and the cat it approaches that level; in the horse and in
+ruminants it rises above it.
+
+With regard to the inferior extremity, its surfaces undergo
+modifications which are further accentuated as we pass from the
+digitigrades to the ungulates, or unguligrades. We know that in man the
+femoral trochlea is continuous behind, without interruption, with the
+condyles--that is to say, that each of the condyles is the continuation
+of one of the lips of the trochlea. We have just said that the trochlea
+is continuous without interruption with the condyles; this is accurate.
+Nevertheless, we must remark that, at the level of the junction of these
+surfaces, the bone presents a slight constriction, which is more marked
+on the external than on the internal aspect. This constriction, which is
+but slightly marked in man, is accentuated in the dog and the cat; in
+the ruminants and the solipeds it is still more pronounced so that we
+may say that in these latter the trochlea and the condyles are almost
+completely separated.
+
+There is another modification in regard to the prominence and extent of
+the two lips of the trochlea. In man, the external lip of the trochlea
+reaches higher than the internal, and it is more prominent in front. In
+the dog, these lips are equal with regard to thickness, but the external
+still reaches higher than the internal; in the cat, they are equal in
+every respect; in ruminants and solipeds the internal lip is wider,
+thicker, and rises higher than the external.
+
+In animals the trochlea is, as a general rule, narrower than in man, and
+the condyles are more prominent posteriorly; so that, when viewed from
+one of the lateral aspects, the inferior extremity of the femur is, in
+them, better developed in the antero-posterior direction.
+
+In birds, the femur is shorter than the bones of the leg; its great
+trochanter is in contact with a prominence which occupies the posterior
+part of the border of the cotyloid cavity. Instead of articulating at
+the level of the knee, with the knee-cap and tibia only, as in man, it
+articulates, in addition, with the superior extremity of the fibula. A
+similar arrangement is found in marsupials and reptiles.
+
+=The Knee-cap.=--This bone, developed in the thickness of the tendon of
+the triceps muscle of the thigh, is in contact, by its posterior
+surface, with the femoral trochlea. The two articular surfaces which are
+applied to the lips of the trochlea present, with regard to their
+extent, an inequality which is in proportion to the arrangement which we
+have above indicated--that is, while in man it is the external surface
+which is the larger, in the horse it is the internal. We shall see what
+the general form of the knee-cap is when we come, later on, to study
+more particularly the posterior limbs of some animals.
+
+
+The Leg
+
+The skeleton of the leg consists of two bones: the tibia and the fibula.
+The tibia is the more internal and the larger of the two; the fibula is
+slender, and situated on the outer side, and a little posterior to, the
+preceding. The fibula is more or less developed according to the
+species; in some it is complete, in others it is very much atrophied.
+
+This peculiarity may be compared with that which we have drawn attention
+to regarding the development of the ulna; but here the seriation is less
+distinct. Not only in the different species, but even in the individuals
+of the same species, the development of the fibula presents little
+regularity. In quadrupeds, the bones of the leg are directed obliquely
+downwards and backwards, so that they form, with the femur, which is
+directed obliquely downwards and forwards, an angle, the apex of which
+is placed at the anterior surface of the knee.
+
+=Tibia.=--The tibia of quadrupeds is readily comparable with that of
+man; as in the case of the latter, its shaft has three surfaces--an
+external, which is hollowed out in its upper portion, and becomes
+anterior below; an internal, slightly convex and subcutaneous; the
+posterior, which presents, in its superior part, a crest, the oblique
+line of the tibia, and some rugosities. The borders separate the
+surfaces. The anterior border, or crest of the tibia, is prominent in
+its superior part; below it gradually disappears in passing towards the
+internal aspect of the inferior extremity. The external and internal
+borders separate the corresponding surfaces from the posterior one.
+
+The superior extremity is thick, and expands in forming three
+tuberosities: two lateral and an anterior. The anterior tuberosity,
+situated at the superior part of the crest of the tibia, is very
+prominent; for this reason the superior extremity is very much expanded
+in the antero-posterior direction--hence it results that this diameter
+is equal to the transverse, and sometimes even greater. In man, it is
+the latter which is the larger. The anterior tuberosity is visible under
+the skin.
+
+The inferior extremity, less thick, is prolonged internally by a
+prominence which corresponds to the internal malleolus of man. In
+animals whose fibula is but slightly developed the tibia presents, on
+the external part of its inferior extremity, a small prominence, which
+replaces the fibular malleolus. The ruminants must, however, be
+excepted, in which we find in this region a special bone, which certain
+authors look on as the inferior part of the fibula (see p. 97). The
+inferior surface of this extremity of the tibia is articular; and is in
+contact with one of the tarsal bones, the astragalus. Because the
+superior surface of this latter has the form of a pulley, a pulley much
+more marked than that on the human astragalus, the corresponding surface
+of the tibia, which has the opposite form, presents two lateral
+cavities, separated by a median ridge, which is directed forwards and
+slightly outwards; this ridge projects into the groove of the pulley.
+
+=The Fibula.=--This bone, situated at the back of the external
+surface of the tibia, is, as we have said, more or less developed. Its
+superior extremity, or head, articulates with the external tuberosity
+of the tibia. Its inferior extremity, when it exists--it is this
+which disappears in animals which have the fibula incompletely
+developed--forms a prominence which, placed on the external surface of
+the inferior extremity of the tibia, articulates with the astragalus,
+and recalls the external malleolus of man.
+
+We have stated above that it is the inferior extremity of the fibula
+which disappears when the bone is incompletely developed; it is
+necessary to except the bat, in which the fibula, fairly well developed
+at its inferior extremity, by which it articulates with the tibia, thins
+off in its superior portion, and does not reach the corresponding
+extremity of the latter. Further, as in this animal the surface of the
+knee, which corresponds to the anterior surface of the same region in
+other animals, is turned backwards, the result is that the fibula is
+situated on the inner side of the tibia, instead of being placed on the
+outer.
+
+
+The Foot
+
+The foot, in animals, as well as in man, is formed of three portions,
+which, as we pass from the part which articulates with the leg towards
+the terminal extremity, are: the tarsus, the metatarsus, and the toes.
+These three portions are the homologues of the carpus, the metacarpus,
+and the fingers, which, as we have already seen in the case of the hand,
+are the osseous groups which form its skeleton. The tarsus is formed of
+short bones, as the carpus is; these are, in man, seven in number. The
+bones are arranged in two rows: one, the posterior, formed of two bones
+superimposed--the astragalus, by which the tarsus articulates with the
+leg, and the calcaneum, which forms the prominence of the heel; and an
+anterior row formed of five juxtaposed ones--the cuboid, situated
+externally, and the scaphoid internally, in front of which are found the
+three cuneiforms. To the tarsus succeeds the metatarsus, whose form
+reminds us very much of that of the metacarpals.
+
+With regard to the toes, which we enumerate in proceeding from the most
+internal to the most external, they are formed of phalanges, which are
+three in number for the four outer toes; but the number is reduced to
+two in the case of the first--that is, the so-called great-toe.
+
+The bones of the tarsus are not seven in all animals; they are fewer in
+ruminants and solipeds. We already know that, in the latter, the
+metacarpals and the digits are equally reduced in number; the same is
+the case for the metatarsals and the toes. We will analyze these
+differences when dealing with the species individually.
+
+When we studied the anterior limbs, we saw in passing from the
+plantigrades to the digitigrades, and finally the ungulates, or
+unguligrades, as the hand became hyperextended, the carpus was raised
+and more and more removed from the ground. We shall establish the
+existence of the same condition in the posterior limbs; in the
+plantigrades the tarsus rests on the ground; in the digitigrades it is
+removed from it; while in the unguligrades the distance which separates
+it from the point of support is still more considerable; and it is,
+indeed, necessary to imagine that if these latter were plantigrades,
+would occupy the position on the ground which is indicated by Fig. 47.
+
+In veterinary anatomy the tarsus is called the _ham_; a name we adopt
+in conformity with usage, but which we cannot but regret, as in human
+anatomy the ham is the region of the posterior surface of the knee.
+
+The general arrangement of the region of the digits of the posterior
+limbs in birds, presents some points of interest.
+
+We shall merely say with regard to the metatarsus, that it is formed by
+a single bone, which in the cock is furnished towards its inferior third
+with a pointed process, the _spur_. At the inferior part, there is,
+however, found another, which is but very slightly developed, and with
+which the first phalanx of the innermost toe articulates.
+
+The toes are, in the majority of species, four in number:[15] an
+internal, which is directed backwards, and corresponds to the great-toe;
+the others are directed forwards. This arrangement is constant in
+grallatores (wading birds), gallinaceae[16] (domestic fowls), and
+raptores (birds of prey).
+
+  [15] In spite of the fact that the custom is to designate the terminal
+       portions of the foot of birds by the name of digits, we prefer to
+       employ here the terms _foot_ and _toes_. In adopting this
+       decision we believe we are acting according to a more didactic
+       method. Homology of names should, in our opinion, always
+       accompany homology of regions.
+
+  [16] With regard to the gallinaceae, we must add that in certain
+       varieties the number of toes is five; those which are directed
+       forwards are three in number; the internal one which passes
+       backward, is double. The two toes which are the subject of this
+       special arrangement are placed very close together, and are
+       nearly always superimposed. This condition is found in the Houdan
+       and Dorking breeds.
+
+[Illustration: FIG. 47.--POSTERIOR LIMB OF THE HORSE PLACED IN THE
+POSITION WHICH IT SHOULD OCCUPY IF THE ANIMAL WERE A PLANTIGRADE: LEFT
+LIMB, EXTERNAL SURFACE.
+
+1, Tibia; 2, astragalus; 3, calcaneum; 4, metatarsus; 5, first phalanx;
+6, second phalanx; 7, third phalanx.]
+
+In climbing birds (parrots, woodpeckers, and toucans), the innermost
+toe is not only directed backward, but the external toe accompanies it
+in that direction; consequently, there are two posterior and two
+anterior toes. Sometimes they are all directed forwards; this
+disposition is found in the martins. In some birds, the number of toes
+is reduced to three: the cassowary shows this reduction; in others, the
+number is still further diminished--the ostrich, for example, has but
+two.
+
+[Illustration: FIG. 48.--SKELETON OF THE FOOT OF A BIRD (THE COCK): LEFT
+SIDE, EXTERNAL SURFACE.
+
+1, Metatarsus; 2, spur; 3, rudimentary metatarsal; 4, first toe; 5,
+second toe; 6, third toe; 7, fourth toe.]
+
+Further, we find that, in general, the number of the phalanges
+increases, when we examine the toes in commencing with the most internal
+(Fig. 48): this has two; then the following one three; that which comes
+next in order has four; and the most external toe has five. The
+phalanges of this last are short; so that, although it is formed by a
+larger number of bones, it is not the longest of the toes.
+
+
+THE POSTERIOR LIMBS IN SOME ANIMALS.
+
+=Plantigrades=: =Bear= (Fig. 33, p. 50).--The external iliac fossa is
+very deep. The femur is longer than the bones of the leg; the great
+trochanter does not reach the level of the head of the femur. The
+fibula is well developed; it is united to the tibia at its superior and
+inferior extremities only.
+
+The foot, which, as in the case of the hand, rests on the ground by the
+whole extent of its plantar surface, presents five toes; the shortest of
+these is the internal--that is, the toe which corresponds to the
+great-toe in man; the third and fourth are the longest, and they are
+almost equal; there is a very slight difference in favour of the fourth,
+which is slightly superior in dimensions to the third.
+
+=Digitigrades=: =Cat=, =Dog= (Fig. 34, p. 52).--The external iliac
+fossa, which looks outwards, is deep; the iliac crest is convex
+anteriorly, the convexity is continued from one iliac spine to the
+other.
+
+[Illustration: FIG. 49.--PELVIS OF THE DOG, SEEN FROM ABOVE.
+
+1, Iliac crest; 2, external iliac fossa; 3, sacrum; AA', bi-iliac
+diameter; BB', bi-ischial diameter.]
+
+In the dog, the distance which separates the anterior iliac spines is
+less than that which separates the ischia (Fig. 49). On a skeleton which
+we measured, the transverse diameter, the distance from the anterior
+iliac spine of one side to that of the opposite side, was 8 centimetres,
+whilst the distance which separated the ischia was 105 millimetres; on
+another skeleton, the first measurement was 127 metres, and the second
+was 146 millimetres. It seems to us unnecessary to multiply examples.
+
+In the cat, the iliac spines are but slightly marked; the result is
+that the iliac crest is almost confounded with the inferior and superior
+borders of the ilium. The two diameters referred to above are almost
+equal (Fig. 50).
+
+We draw particular attention to what we have just noted in regard to the
+transverse proportions of the iliac and ischiatic regions of the dog and
+the cat. These relations are evidently of importance with regard to
+shape, since the iliac crests and the ischia are noticeable beneath the
+skin.
+
+[Illustration: FIG. 50.--PELVIS OF A FELIDE (LION), VIEWED FROM ABOVE.
+
+1, Iliac crest; 2, external iliac fossa; 3, sacrum; AA', bi-iliac
+diameter; BB', bi-ischial diameter.]
+
+In the dog, the shaft of the femur is slightly convex in front; but in
+the cat it is straight. The borders of the shaft are slightly marked, so
+that it is almost cylindrical. The _linea aspera_, less prominent than
+in man, gains in width what it loses in elevation; it constitutes what
+may almost be called a rough _surface_. This surface is narrower in its
+middle portion than at its extremities, where it bifurcates to go
+upwards to the two trochanters, and downwards to the two condyles. At
+the superior extremity, the neck is short, the great trochanter reaching
+almost to the level of the head of the femur; the digital _cavity_,
+which is situated on the internal surface of the great trochanter, is
+very deep. At its inferior extremity it projects strongly backward. The
+trochlea is narrow; in the cat its two lips are equally prominent, while
+in the dog the external is a little more elevated than the internal,
+which on its part is a little thicker. The trochlea is still more
+independent of the condyles than in the human femur; it is separated
+from these latter by a slight constriction.
+
+The knee-cap is long and narrow.
+
+The tibia of the dog is slightly curved from before backward: it has the
+form of an elongated S; this conformation is in great part due to the
+very marked projection of the anterior tuberosity and of the superior
+portion of the crest, which, a little below that tuberosity, turns
+abruptly backwards, and thus describes a curve the concavity of which is
+directed forward. The superior part of the external surface is very much
+hollowed out.
+
+The superior extremity is much thicker than the inferior one. It is not
+only wide in the transverse direction, but is more especially extended
+from before backwards; the prominence of the anterior tuberosity is the
+cause of the elongation of this antero-posterior diameter. On the
+posterior part of the external tuberosity is found a surface to which
+the superior extremity of the fibula is applied.
+
+The inferior extremity presents an articular surface, which is formed of
+two lateral cavities, separated by a crest, which is directed obliquely
+forwards and outwards. The internal part is prominent, and forms the
+internal malleolus.
+
+With regard to the fibula, it is united to the tibia by its extremities
+and by the inferior half of its shaft. This latter is more expanded
+below than in its upper part. The superior extremity is flattened from
+without inwards. The inferior extremity projects beyond the articular
+surface of the tibia, and forms the external malleolus, which, instead
+of, as in man, descending further than the tibial malleolus, stops at
+the same level, and even descends a little less than does the latter.
+
+In the cat, the curve of the tibia is less pronounced; this is due to
+the fact that the crest, instead of being concave in its middle portion,
+is slightly convex anteriorly. The fibula, less flattened than that of
+the dog, is united to the tibia by its extremities only, and is separate
+in the rest of its extent.
+
+The bones of the tarsus are seven in number, and arranged as in man,
+with this difference (which is easily comprehended), that their general
+relations are changed on account of the vertical direction of the
+tarsus. For example, the astragalus, instead of being above the
+calcaneum, is situated in front of it; the cuneiform bones, instead of
+being situated in front of the scaphoid, are found below it, etc.
+
+These animals have but four well-developed metatarsals; that which
+corresponds to the great-toe is represented merely by a small
+style-shaped bone, situate at the internal part of the region.
+
+Nevertheless, we find this toe fully developed in some dogs.
+Notwithstanding this, the bones which form it are, however, but
+rudimentary, and much smaller than those of the innermost digit of the
+fore-limb.
+
+Sometimes it is double; this condition is demonstrable in individuals
+belonging to breeds of large size. The median metatarsals are more fully
+developed than the other bones of the same region which are next them.
+Viewed as a whole, the metatarsal bones are a little longer than the
+metacarpals; the result is that the distance which separates the tarsus
+from the ground is a little greater than that which separates the carpus
+from the plane on which the anterior limbs rest. The length of the
+calcaneum still further exaggerates this difference, and, as in the
+animals with which we shall occupy ourselves later on, the projection
+which this bone forms is distinctly higher than that which is produced
+by the pisiform.
+
+The metatarsus, as a whole, is a little narrower than the metacarpus;
+not only on account of the presence of a thumb in the anterior limb,
+but, further, because the bones of this latter region are wider than
+those of the corresponding part of the posterior limb.
+
+The phalanges closely resemble those of the anterior limbs.
+
+=Unguligrades=: =Pig= (Fig. 38, p. 58).--The pelvis in this animal
+presents a few of the characters which we shall again meet with in the
+ruminants and the solipeds; however, the posterior (or internal) iliac
+spines are relatively more widely separated from one another than in the
+latter. This arrangement reminds us of that found in the carnivora.
+
+The femur presents nothing very special. The knee-cap is thick, and
+ovoid in outline.
+
+The fibula is completely developed, as in the carnivora; and is
+connected with the tibia at both its extremities.
+
+The tarsus consists of seven bones. The astragalus and the calcaneum
+differ slightly from those of ruminants.
+
+The foot, like the hand, has two median digits which rest on the ground
+by their third phalanges; and an internal and an external digit, which
+are removed from it. The metatarsals are a little longer than the
+metacarpals.
+
+[Illustration: FIG. 51.--PELVIS OF THE OX: SUPERIOR SURFACE.
+
+1, Iliac crest; 2, external iliac fossa; 3, sacrum; AA', bi-iliac
+diameter; BB', bi-ischiadic diameter.]
+
+=Unguligrades=: =Sheep=, =Ox= (Fig. 39, p. 61).--The pelvis of ruminants
+of this group closely resembles that of the horse, which we will study
+later on (see p. 99). That which we must at once point out is that, with
+regard to the ratio formed by a comparison of the bi-iliac and
+bi-ischiatic diameters, it may be placed between the ratio obtained in
+comparing those diameters in the pelvis of the carnivora and that of the
+solipeds. Indeed, in the ruminants, the distance which separates the
+ischia exceeds the width of one iliac only, and does not equal, as in
+the felide, the total width of the anterior part of the pelvis (Fig.
+51). In the skeleton of the ox, which forms part of the anatomical
+museum of the Ecole des Beaux-Arts, the bi-ischiadic diameter is 39
+centimetres, whilst the width of one iliac crest is 29 centimetres, so
+that, in contrast to that which we find in the dog, the width of the
+ischiadic region is less than that formed in front by the addition of
+the iliac crests.
+
+The great trochanter is large, and extends beyond the level of the plane
+in which the head of the femur is found.
+
+In the ox, the linea aspera, instead of being a narrow crest, is spread
+out, and forms in reality a surface; the posterior surface of the femur.
+At the inferior and external part of this surface is situated a cavity
+which surmounts the corresponding condyle, and is known as the
+_supracondyloid fossa_. On the internal part of the same region there
+are a series of tubercles, which, because of their position in relation
+to the corresponding condyle, constitute the _supracondyloid crest_.
+
+The internal lip of the trochlea is much thicker and much more prominent
+than the external.
+
+The details which we have just now examined in connection with the ox
+are less marked in the sheep.
+
+The trochlea, narrow as a whole, is clearly separate from the condyles
+by a very marked constriction.
+
+The patella, which is thickened in the antero-posterior direction, has
+the shape of a triangular pyramid with the base upwards. Its posterior
+surface, which articulates with the trochlea, presents an arrangement
+which is adapted to the disposition of this latter--that is to say, the
+surface which is in contact with the internal lip is larger than that
+which articulates with the lip of the opposite side.
+
+The tibia of the ox is proportionately shorter than that of the sheep.
+The shaft of this bone is flattened from before backwards, in its
+inferior half. The median crest of the articular surface of the inferior
+extremity is the most prominent part of that region.
+
+[Illustration: FIG. 52.--TARSUS OF THE OX: POSTERIOR LEFT LIMB,
+ANTERO-EXTERNAL SURFACE.
+
+1, Tibia; 2, coronoid bone of the tarsus; 3, superior articular surface
+of the astragalus; 4, inferior articular surface of the astragalus; 5,
+calcaneum; 6, cuboido-scaphoid bone; 7, great cuneiform bone--the small
+cuneiform bone is situated at the back of the latter; 8, principal
+metatarsal--the small, or rudimentary, metatarsal bone is very small; it
+is situated at the back of the preceding, and is not to be seen in the
+sketch. It would be visible if the view were directly lateral, but then
+the superior and inferior articular surfaces of the astragalus would be
+less apparent.]
+
+The fibula is extremely atrophied. The shaft and superior extremity of
+this bone are represented merely by a simple ligamentous cord, which is
+sometimes ossified. There remains of the fibula, as a portion well and
+distinctly developed, the inferior extremity only. This presents itself
+under the form of a small bone situated in the region ordinarily
+occupied by the inferior extremity of the outer bone of the leg--that is
+to say, the external part of the inferior extremity of the tibia; this
+little bone articulates with the astragalus and the calcaneum. Some
+authors consider it to be a tarsal bone, and describe it under the name
+of the coronoid bone of the tarsus (Fig. 52, 2). It is not, perhaps,
+quite legitimate to describe it as a bone of this region, for it has
+not a homologue in the tarsus of other animals. Its external surface is
+rough; its superior border is furnished with a small pointed process
+occupying a depression which is provided for it by the tibia. It reaches
+lower down than the latter, and forms in this way a sort of external
+malleolus, which frames, on the outer aspect, the mortise in which the
+astragalus is maintained.
+
+The tarsus, as a whole, has an elongated form; it is formed of five
+bones: the astragalus, calcaneum, cuboid and scaphoid, which coalesce,
+to form a single bone, and two cuneiform bones, which correspond to the
+second and third cuneiform bones of the human foot. These cuneiforms are
+called, from their size, commencing internally, by the names small and
+great cuneiform.
+
+The calcaneum is long and narrow; it is longer than that of the horse;
+it is on the anterior and external part that the bone (coronoid tarsal
+bone) which represents the inferior extremity of the fibula is situated.
+It forms the prominence known as _the point of the ham_, a prominence
+which is no other than the heel, which, in the unguligrades, is, as we
+have already said, very far removed from the ground.
+
+The astragalus, which is elongated in the vertical direction, has three
+articular surfaces disposed in the form of trochleae: a superior
+trochlea, which is in contact with the skeleton of the leg, and which is
+present in all animals; an inferior, which replaces the articular head
+found on the anterior aspect of the astragalus in man; this articulates
+with the portion of the scaphoido-cuboid that corresponds to the
+scaphoid; and, lastly, a posterior trochlea with which the calcaneum
+articulates. Of these three trochleae, the superior is the most strongly
+marked. Between this latter and the inferior is found, on the anterior
+surface of the astragalus, a deep depression, which, during flexion of
+the foot on the leg, receives a prominence which the inferior extremity
+of the tibia presents in its median portion.
+
+We can easily recognise the trochleae which we have been discussing, in
+the little bones which children use 'to play at bones'; these bones are
+no other than the astragali of sheep.
+
+We have already mentioned that the scaphoid and the cuboid are
+ankylosed; they form by their union an irregular bone, on which the
+astragalus and calcaneum are supported.
+
+The cuneiforms articulate with the internal half of the superior
+extremity of the principal metatarsal; the external half of this
+metatarsal articulates with the portion of bone which represents the
+cuboid.
+
+The metatarsus is represented by a principal metatarsal, formed by the
+coalescence of two metatarsals; we also find in this region a very small
+rudimentary metatarsal.
+
+The metatarsus is a little longer than the metacarpus; its transverse
+measurement is a little less; on the other hand, it is a little thicker
+in antero-posterior direction; from these two differences it results
+that the body of the metatarsus is quadrilateral, whereas the metacarpus
+presents only an anterior and a posterior surface.
+
+The rudimentary metatarsal is a very small roundish bone, situated at
+the back of the superior extremity of the principal metatarsal.
+
+The phalanges closely resemble those of the anterior limbs;
+nevertheless, the first and second phalanges differ from the latter in
+the fact that they are a little longer and narrower.
+
+At the back of the metatarso-phalangeal articulations, as in the
+corresponding region of the anterior limbs, are found the sesamoid
+bones. Such also exist at the articulations of the second and third
+phalanges.
+
+=Unguligrades=: =Horse= (Fig. 40, p. 64).--The pelvis of the horse
+presents a general form which sharply differentiates it from that of the
+carnivora; in fact, the ilium is twisted in such a way that the external
+iliac fossa does not look outwards, but upwards. It results from this
+twist that the anterior iliac spine, which we have seen to be directed
+downwards in the carnivora, has become external; and this prominence is
+much farther removed from the vertebral column than in the dog or cat.
+On the other hand, the posterior iliac spine, which is directed upwards
+in the carnivora, has become internal; it is also placed nearer to the
+vertebral column, with the result that the distance which separates this
+spine from that of the bone of the opposite side is proportionately
+less.
+
+The internal iliac spine, which is conical in shape, and curved upwards,
+forms a prominence known as _the angle of the crupper_; the external
+iliac spine, thick and provided with tuberosities, forms a
+clearly-defined prominence; this is the angle of the _haunch_.
+
+The iliac crest, extending directly from one spine to the other, is
+curved, its concavity being turned upwards. The external iliac fossa,
+which looks upward, is limited anteriorly by this crest, and is, like
+the latter, slightly hollowed. The portion of the bone which connects
+the ilium to the region occupied by the cotyloid cavity is extremely
+narrow; posteriorly, the bone enlarges again to form the ischial and
+pubic portions.
+
+The tuberosity of the ischium, thick and curved upwards, but less so
+than in the ox, forms the most prominent part of the posterior border of
+the region of the thigh; this projecting portion, so sharply defined in
+spare subjects, is known as the _point_ or _angle of the buttock_.
+Contrary to what we have indicated in the case of the dog, the distance
+which separates the ischiatic tuberosities is inconsiderable in
+proportion to that which we find between the external iliac spine of one
+side and that of the opposite. The bi-ischiatic diameter does not even
+equal the width of one iliac bone measured at the level of its crest
+(Fig. 53). On the skeleton of the horse in the Ecole des Beaux-Arts, the
+distance which separates the tuberosities of the ischia is 225
+millimetres; that between the two spines of each iliac bone is 25
+centimetres.
+
+The anterior region of the crupper is thus much broader than that
+occupied by the ischia.
+
+The femur is relatively short. Its shaft is rectilinear, and does not
+present the anterior convexity which is found on the human femur, and
+which we indicated when discussing that of the dog. The shaft of the
+bone, instead of being prismatic and triangular, presents four surfaces;
+the anterior, internal, and external, almost pass into each other, being
+separated one from the other merely by rounded and slightly marked
+borders; the posterior surface, which is plane, replaces the linea
+aspera, which in the horse, instead of presenting the appearance of a
+crest, is considerably widened. The numerous irregularities which this
+surface presents give insertion to the muscles which correspond to those
+attached to the linea aspera.
+
+Between this posterior surface and the external is found a rough
+prominence which curves forward; this was designated by Cuvier the
+_third trochanter_; it replaces the external branch of the superior line
+of bifurcation of the linea aspera; other authors call it the
+_infratrochanteric crest_, because it is situated below the great
+trochanter. At the inferior part of the same region is found a deep
+fossa, the borders of which are rough; this is the _supracondyloid
+fossa_.
+
+[Illustration: FIG 53.--PELVIS OF THE HORSE: SUPERIOR SURFACE.
+
+1, Iliac crest; 2, external iliac fossa; 3, sacrum; AA', bi-iliac
+diameter; BB', bi-ischiatic diameter.]
+
+Between the posterior surface and the internal are found: above, the
+lesser trochanter, which is long and rough; below, at the level of the
+supracondyloid fossa, an equally rough surface known by the name of the
+_supracondyloid crest_.
+
+The superior extremity is flattened from before backwards. The neck is
+not well marked. The great trochanter is very prominent, and projects
+beyond the level of the head of the femur. We divide the great
+trochanter into three parts: the summit, which is the most elevated
+portion; the convexity, which is situated in front; and the crest,
+formed by muscular impressions, situated outside and below the
+convexity. The digital fossa is situated behind and below the summit of
+the great trochanter. With regard to the lesser trochanter, it is placed
+so far down that it really forms part of the shaft of the bone, with
+which, besides, we have described it.
+
+On the inferior extremity of the femur are two condyles and a trochlea;
+the condyles are clearly separated from this latter by a marked
+constriction.
+
+The trochlea is directed with a slight obliquity downwards and inwards;
+its internal lip is much thicker and more prominent than the external;
+this is, accordingly, a condition exactly the opposite of that which
+characterizes the corresponding region of the human femur.
+
+The knee-cap is lozenge-shaped; its superior angle projects upward, and
+produces a prominence at the part which corresponds to the base of the
+human patella, the part which is here the thickest portion of the bone.
+Its anterior surface is convex and rough. Its posterior surface presents
+two lateral articular facets, separated by a crest; this surface is in
+contact with the trochlea of the femur, and, as it is the internal lip
+of the latter which is the more developed, it results therefrom that the
+internal articular surface of the knee-cap is larger than the external.
+
+The knee-cap contributes to the formation of the region of the posterior
+limb which is called the _stifle_.
+
+The tibia is large in its upper portion; in its inferior part it is
+flattened from before backwards. The posterior surface of the shaft
+presents an oblique line, below which are found vertical rough lines for
+the insertion of muscles. The external surface is hollowed out in its
+upper part. The anterior tuberosity of the tibia rises just to the level
+of the flat articular surface; it is hollowed in its median portion by a
+vertical groove of elongated form, which receives the ligament that
+binds the knee-cap to the tibia. The external tuberosity is more
+prominent than the internal; in it is found a groove for the passage of
+the anterior tibial muscle.
+
+The inferior extremity, flattened from before backwards, presents a
+surface which is moulded on the trochlea of the astragalus; the median
+crest of this surface is thick, and descends lower posteriorly than the
+tuberosities which are situated on the external and internal aspects of
+this extremity.
+
+Of the two tuberosities, that which is internal is comparable to the
+internal malleolus of man, the one on the outer side forms a sort of
+external malleolus; but this latter here belongs to the tibia, and not
+to the fibula.
+
+The fibula, in fact, does not reach the inferior extremity of the tibia;
+it is a poorly developed bone, elongated and terminating inferiorly in a
+point, at the middle of the shaft of the tibia or at its lower third.
+Its superior extremity, which is slightly expanded, articulates with the
+tuberosity which occupies the outer aspect of the corresponding
+extremity of the tibia.
+
+The bones of the tarsus are six in number: the calcaneum and astragalus
+form the upper row; the cuboid, scaphoid, and two cuneiforms form the
+lower (Fig. 54).
+
+The astragalus has not, as in ruminants, an inferior trochlea for
+articulation with the scaphoid; this portion of the bone presents a
+surface which is slightly convex. It articulates with the tibia by a
+trochlea that occupies not only the superior surface, but also the
+anterior. This trochlea, which is directed slightly obliquely downwards
+and outwards, has a very pronounced form; its lips, which are extremely
+prominent, determine by their anterior part one of the features which we
+recognise on the anterior aspect of the _ham_--a feature which is still
+more accentuated when the metatarsus (_canon_) is extended on the leg.
+On the internal surface of the astragalus is found a tubercle, which
+forms a projection in the corresponding region of the ham.
+
+The calcaneum, which is not quite so long as that of the ox, forms by
+its summit a prominence which is called _the point of the ham_.
+
+The cuboid is small; the scaphoid is large, and flattened from above
+downwards. Of the two cuneiforms, the more external is the larger; it
+closely resembles the scaphoid; it is flattened from above downwards as
+is the latter; but it is a little smaller in size. The small cuneiform,
+which occupies the inner side of the tarsus, is the smallest bone in
+this region; it is sometimes divided into two parts; this raises the
+number of the cuneiforms to three, and that of the bones of the tarsus
+to seven.
+
+[Illustration: FIG. 54.--TARSUS OF THE HORSE: LEFT POSTERIOR LIMB,
+ANTERIOR SURFACE.
+
+1, Tibia; 2, internal tuberosity of the inferior extremity of the tibia
+(homologue of the internal malleolus of man); 3, external tuberosity of
+the inferior extremity of the tibia (homologue of the external
+malleolus); 4, median crest lodged in the groove of the pulley of the
+astragalus; 5, pulley of the astragalus; 6, internal tuberosity of the
+astragalus; 7, calcaneum; 8, cuboid; 9, scaphoid; 10, great cuneiform,
+the small cuneiform is placed behind this latter; 11, principal
+metatarsal; 12, external rudimentary metatarsal. The internal
+rudimentary metatarsal, being more slender than the external, does not
+appear in the figure.]
+
+The bones of the metatarsus and the phalanges are equal in number to the
+corresponding bones in the anterior limbs; they are formed on a type
+analogous to that of these latter. Accordingly, we shall merely indicate
+the differences which characterize them.
+
+The principal metatarsal is longer than the metacarpal of the same
+class; its shaft is more cylindrical; its inferior extremity is somewhat
+thicker. The external rudimentary metatarsal is better developed than
+the internal; in the metacarpus the reverse is the case.
+
+The phalanges so far resemble those of the anterior limb that, as
+differential characters, we need point out only the following: the first
+phalanx of the hind-foot is a little shorter than that of the fore-foot;
+its inferior extremity is a little narrower, and its superior extremity
+a little thicker. The second phalanx is a little less expanded
+laterally.
+
+The difference in appearance which the three phalanges, anterior and
+posterior, respectively present are to be borne in mind; for they are
+correlated to the general form of the fore and hind feet. We will
+establish this point when we come to study the hoof (see Figs. 101 and
+102, p. 257). In the fore-foot the ungual phalanx has its inferior
+surface limited externally by a circular border, while the same bone of
+the hind-foot has this surface a little narrower, more concave, and
+limited by two curved borders which unite anteriorly to form an
+angle--an arrangement which gives to the general outline of this region
+the form of the letter V.
+
+
+Articulations of the Posterior Limbs
+
+=The Coxo-femoral Articulation.=--The head of the femur is received in
+the cotyloid cavity; these are the osseous surfaces in contact in this
+articulation. They are maintained in position by a fibrous capsule and a
+round ligament. To this latter is found attached, in the horse, a
+fasciculus which, commencing, as does the round ligament, at the
+depression on the head of the femur, emerges from the cotyloid cavity by
+the notch which is present in its circumference, and is attached to the
+anterior border of the pubes, to blend with the tendon of the rectus
+muscle of the abdomen. This is the pubio-femoral ligament.
+
+The movements which this joint permits are the same in the quadrupeds as
+in man, but less extensive. They are: flexion and extension, abduction
+and adduction, the two latter being much more limited than the former.
+There is also rotation.
+
+By flexion, the inferior extremity of the femur is directed forwards;
+the bone of the thigh then takes a more oblique direction than the
+normal. This movement takes place, for example, when the animal carries
+forward one of its hinder limbs. Extension, which takes place in an
+inverse sense, is produced when the foot is fixed on the ground, while
+the body is projected forward. It is also produced in the action of
+kicking.
+
+As for the lateral movements--viz., abduction and adduction--they are
+less extensive than the preceding movements. The absence of the
+pubio-femoral ligament in other quadrupeds than the horse explains why
+in them abduction is less limited than in the latter. Indeed, it is the
+tension of this ligament, occasioned by the abduction of the thighs,
+which arrests more quickly the movement in question.
+
+=Articulation of the Knee.=--This articulation, as in man, is formed by
+the femur, the patella, and the tibia.
+
+In the horse the ligament of the patella is not single, but consists of
+three parts, designated, on account of their position, by the respective
+names of external, internal, and median patellar ligaments. The two
+former come from the angles on the corresponding borders of the
+knee-cap; the median springs from the anterior surface and inferior
+angle of the same bone. They all three pass to their termination on the
+anterior tubercle of the tibia. The external ligament is the strongest,
+and the internal ligament the least developed.
+
+In the dog, the cat, the pig, and the sheep, the patellar ligament
+consists of a single band. The articulation is further strengthened on
+the sides by lateral ligaments--an internal and an external.
+
+With regard to the principal movements, these are flexion and extension,
+to which may be added movements of rotation of limited extent. In
+flexion, the leg bends on the thigh; its inferior extremity is directed
+upwards and backwards; the angle which the tibia naturally forms with
+the femur becomes less obtuse.
+
+But it should be understood that one part of this description--that
+which has relation to the leg--holds good only when the femur is in its
+normal condition, or in flexion. Indeed, at the close of the movement in
+which, during a step, the foot is in contact with the ground--that is,
+at the termination of the resting stage--the inferior extremity of the
+tibia is directed backwards. But the femur is then in a state of
+extension, and in regard to this latter the attitude of the leg is
+unchanged.
+
+[Illustration: FIG. 55.--EXTENSION OF THE LEG: RIGHT POSTERIOR LIMB OF
+THE HORSE, EXTERNAL SURFACE. (AFTER A CHRONOGRAPHIC STUDY BY PROFESSOR
+MAREY.)]
+
+At this moment, notwithstanding the direction, which recalls that which
+it has at the time of flexion, the leg is not bent on the thigh; on the
+contrary, it is almost in the line of its continuation (Fig. 55). As we
+have done in connection with the articulations of the anterior limbs, we
+borrow this figure from the interesting chronophotographic studies of
+Professor Marey.[17]
+
+  [17] E. J. Marey, 'Analysis of the Movements of the Horse by the
+       Chronophotograph' (_La Nature_, June 11, 1898).
+
+=The Tibio-tarsal Articulation and of the Bones of the Tarsus.=--In the
+region which veterinary anatomists call the ham, the articulations of
+the leg and foot alone call for special study in the case of the horse.
+The articulations of the bones of the tarsus, and of these with the
+metatarsus, do not offer any interest with regard to mobility, this
+being almost wholly absent at that level.
+
+The leg and the astragalus, in a general way, are placed in contact by
+such articular surfaces that the resulting joint, which is a true hinge,
+permits movements of flexion and extension only. Indeed, as we have
+indicated above, the tibia is furnished, on the inferior surface, with a
+crest that fits into the deep groove which is situated on the
+corresponding surface of the astragalus.
+
+During flexion, the anterior surface of the foot tends to approach the
+anterior surface of the leg, the angle formed by these two segments
+becoming more and more narrowed. The displacement in the opposite
+direction characterizes extension.
+
+In other quadrupeds, the articulations which bind together the bones of
+the tarsus possess a little more freedom of movement. The shape of these
+bones, and particularly the shape of the surfaces of the astragalus,
+which are in contact with them, allow movements in this region, in the
+case of the dog and cat, which, without being so extensive as those of
+the human foot, in the subastragaloid articulation, nevertheless, recall
+the mobility which we find in the human species at this level--that is
+to say, rotation, abduction, and adduction of the foot.
+
+As for the articulations of the metatarsus with the phalanges, and of
+the phalanges with one another, they resemble those of the anterior limb
+too closely that it should be necessary to study them here. Such a study
+would be, in this case, but a repetition (see p. 76, a description of
+the articulations in question).
+
+
+THE HEAD IN GENERAL, AND IN SOME ANIMALS IN PARTICULAR
+
+When we compare, by the examination of one of their lateral aspects, the
+skull of man and the same region in other mammals, it is easy to observe
+that the relative development of the cranium and face is entirely
+different. In the case of man the cranium is large, and the face
+relatively small; in animals the face is proportionally much more highly
+developed. The measure of the facial angle permits us to note these
+differences, and the figures relative to the value of this angle are
+sufficiently demonstrative to induce us to indicate those which are, in
+a general way, connected with some of the forms in individuals which
+here occupy our attention. In the first place, we must remember that the
+angle in question is more acute, as the cranium is less developed in
+proportion to the facial region (Figs. 56 and 57). It is especially to
+this character that we wish to draw attention.
+
+  Man      70 deg.-80 deg.
+  Cat      41 deg.
+  Dog      28 deg.-41 deg.
+  Sheep    20 deg.-25 deg.
+  Ox       18 deg.-20 deg.
+  Ass      12 deg.-16 deg.
+  Horse    11 deg.-13 deg.
+
+Besides, in animals the cranium is very prominent superiorly, and the
+face, more or less elongated, is sharply projected downwards and
+forwards; in man the cranial region occupies not only the superior, but
+also the posterior part; the face is short and of a compact form. The
+human head, in its general aspect, may be compared to a sphere, while
+the skull of the quadrupeds presents the aspect of a quadrangular
+pyramid, with the base turned upwards and the summit at the incisor
+teeth.
+
+=Direction of the Head.=--Before entering on the study of the bones of
+the head, it is necessary, in our opinion, to agree as to the position
+in which we shall suppose it to be placed.
+
+The question may seem to be one of little importance; nevertheless, it
+cannot be regarded as indifferent, since authors are not all agreed on
+this subject.
+
+Some suppose it to be placed vertically--that is, with the incisor teeth
+turned directly downwards. Others, on the contrary, suppose it to be
+placed horizontally, resting on the whole length of the lower jaw, the
+face being then turned upwards. These two extreme methods of arrangement
+appear to us to possess inconveniences--at least, for comparison with
+the human head.
+
+[Illustration: FIG. 56.--HUMAN SKULL: MEASURE OF THE FACIAL ANGLE BY THE
+METHOD OF CAMPER. ANGLE BAC = 80 deg.
+
+The internal wall of the cranial cavity is marked by the dotted line.]
+
+[Illustration: FIG. 57.--SKULL OF THE HORSE: MEASURE OF THE FACIAL ANGLE
+BY THE METHOD OF CAMPER.[18] ANGLE BAC = 13 deg.
+
+The internal wall of the cranial cavity is shown by the dotted line.]
+
+  [18] We have indicated on this sketch of the skull of the horse the
+       facial angle measured by the method of Camper, in order that the
+       correspondence with Fig. 56 may be more complete. But it is
+       certain that the procedure here employed is in practice not
+       satisfactory, since the apex of the angle, as we can demonstrate,
+       is found to be situated within the contour of the head, and that,
+       consequently, it is rather difficult to localize it precisely in
+       the case of a given skeleton. Further, because of the absence of
+       the base of the nose in the complete skull, the auriculo-nasal
+       line cannot be accurately fixed. It would be the same for most
+       other animals. This is why the method employed for these latter
+       is preferably that of Cuvier, or, again, that of Cloquet. In the
+       former, the apex of the angle of Camper is transferred to the
+       free border of the upper incisors, but these teeth may be absent,
+       and, on the other hand, ruminants are destitute of them. In the
+       second, the same apex is placed at the alveolar border, and the
+       angle then becomes fairly easy to appreciate.
+
+Indeed, if, when the head is vertical, the same regions of the face
+(forehead, nose) are, in the case of animals as well as man, turned
+forward, the lower jaw ceases to merit its appellation, as it is then
+situated, not below, but behind the upper. Furthermore, if this
+position is chosen, for example, for modelling or drawing, it cannot be
+obtained without difficulty when we have to deal with an isolated piece
+of the skeleton, on account of the absence of equilibrium, which it is
+necessary to obviate. It is true that the question of convenience should
+not take precedence of all others, and it suffices for us in this
+connection to recall, in regard to the human pelvis, that, although the
+older anatomists used to represent it as resting commodiously on the
+three angles which terminate it at its lower part (ischial tuberosities
+and coccyx), this attitude being false, it is customary now to incline
+the superior aspect forwards, inasmuch as this arrangement more nearly
+conforms to reality, in spite of the fact that it is a little more
+difficult so to dispose an isolated pelvis. Further, to return to the
+head; if its vertical direction can be demonstrated, for example, in
+many horses, it is not sufficiently general to be adopted as the classic
+position.
+
+In regard to the facility of placing in position, the horizontal
+direction is certainly to be preferred; but this is also far removed
+from the natural position in the animal while in the state of repose. On
+the other hand, the mind is not satisfied with the idea that certain
+regions of the face, such as the nose and the forehead, are then
+directed upwards. And yet it is necessary to come to a decision, seeing
+that what we are now investigating applies also to the position to which
+it is necessary to give the preference in placing the skeleton of the
+head when we wish to draw it in profile. That which we adopt is a
+compromise, but to us it seems more rational.
+
+The position of the head of the horse, to be normal, should be such as
+to give it an inclination of 45 deg. In this case the lower jaw is still
+posterior; and, for this reason, we see in adopting this position some
+inconveniences from a didactic point of view. Accordingly, we will
+suppose the head brought a little nearer to the horizontal, and this,
+from the imaginative point of view, has certainly an advantage which we
+cannot afford to neglect when addressing artists.
+
+Indeed, let us suppose that to a clay model of a human head we wish to
+give the aspect of the head of a quadruped. We should elevate the
+occiput; and then, taking hold of the lower part of the face, we should
+lengthen it, not in a direction precisely antero-posterior, but
+downwards and forwards. It is obviously this latter procedure which, on
+the other hand, is carried out when a person wishes to give to his own
+face some resemblance to the muzzle of a quadruped.
+
+It is true that, in the position we have adopted, the face is directed
+obliquely downwards and forwards, and that there may result a certain
+confusion in describing the position of its different parts. On
+this account, with the object of not making complications, we
+purpose, for the present, to substitute, for example, for the term
+'antero-superior'--which when speaking of the position of the forehead
+and nose would be more exact--the term 'anterior,' which is sufficiently
+comprehensible. The mouth will be, for the same reason, referred to as
+being situated at the inferior part of the face, and not the
+antero-inferior.
+
+=The Skull.=--The elevation of the cranial region becomes especially
+appreciable when we examine the occipital bone. Before verifying this
+fact, it is not superfluous to recall the general arrangement which this
+bone presents in the human skull. A portion of the occipital bone
+occupies the base of the skull; but this base in man is horizontal; to
+this region succeeds the shell-shaped portion of the occipital bone,
+which, passing vertically upwards, forms with the preceding portion an
+angle situated at the level of the external occipital protuberance, and
+of the curved line which starts from it on each side. In animals a
+portion of the occipital bone is horizontal, it is true; but this bone
+being sharply bent at the level of the occipital foramen and condyles,
+the result is that the portion which surmounts these latter looks
+backwards, and is limited above by the external occipital protuberance,
+which forms the culminating point of the skull; this point is situated
+between the ears.
+
+[Illustration: FIG. 58.--SKULL OF ONE OF THE FELIDAE (JAGUAR): LEFT
+LATERAL ASPECT.
+
+1, Posterior surface of the occipital bone; 2, external occipital
+protuberance; 3, condyle of the occipital bone; 4, jugular process; 5,
+parietal bone; 6, frontal bone; 7, orbital process; 8, orbital cavity;
+9, squamous portion of the temporal bone; 10, external auditory canal,
+in front of which is situated the zygomatic process; 11, tympanic bulla;
+12, superior maxillary bone; 13, intermaxillary or incisor bone; 14,
+nasal bone; 15, anterior orifice of the nasal cavity; 16, malar bone;
+17, ungual or lachrymal bone; 18, inferior maxillary bone; 19, condyle
+of the inferior maxillary bone; 20, coronoid process; 21, incisor teeth;
+22, canine teeth; 23, molar teeth.]
+
+[Illustration: FIG. 59.--SKULL OF THE LION: LEFT LATERAL ASPECT.
+
+This figure is intended to show that in the lion the contour of the face
+between the nasal bones and the cranial region is more flattened than in
+other felidae, such as the tiger, jaguar, panther, and domestic cat. This
+difference is shown by comparison of this figure with the preceding one
+(Fig. 58). We are indebted to M. Tramond, the well-known naturalist, for
+the indication of this differential character which, from the artistic
+plastic point of view, is one of real interest.]
+
+This protuberance, prolonged on each side by the superior curved line of
+the occipital bone, is so much the more prominent as this bone bends
+sharply a second time, so as to form a third portion, which, looking
+forwards, forms part of the anterior aspect of the skull, and proceeds
+to articulate with the parietals. On this third portion is found a crest
+which, proceeding from the occipital protuberance, is continuous in
+front with the parietal crests, to which we will again refer in speaking
+of the parietal bones.
+
+On the inferior surface of the human occipital bone are found, at the
+level of, and external to, the condyles two bony elevations which bear
+the name of _jugular eminences_. They are long in quadrupeds, and
+constitute what are designated by some authors the _styloid processes_,
+but they must not be confounded with the processes of the same name
+which in the case of man form part of the temporal bone. These processes
+are very highly developed in the pig, horse, ox, and sheep.
+
+In the ox, the occipital bone is deprived of the protuberance, and is
+not bent on itself in the anterior portion, neither does it form the
+most salient part of the skull; this latter, which is situated at the
+level of the horns, belongs to the frontal bone. In the pig, also, the
+occipital bone is not bent upon itself in its anterior portion, but
+forms the summit of the head. The occipital protuberance, hollowed on
+its posterior surface, rises vertically, and rests upon the parietal
+bone, with which it forms an acute angle.
+
+The parietals, two separate bones in the dog and the cat, but fused in
+the median line in the ox, sheep, and horse, are of special interest in
+regard to the two crests which, in the carnivora, and also in the pig
+and the horse, occupy their external surface, and, after diverging from
+one another, are continued by a crest which crosses the frontal bone
+and ends at the external orbital process of the latter bone.
+
+These crests, known as the _parietal_ or _temporal crests_, recall both
+in position and relations the temporal curved line of the parietal bone
+of man. They contribute, as in the case of the latter, to the formation
+of the boundaries of the temporal fossa.
+
+[Illustration: FIG. 60.--SKULL OF THE DOG: LEFT LATERAL ASPECT.
+
+1, Posterior surface of the occipital bone; 2, external occipital
+protuberance; 3, occipital condyle; 4, jugular process; 5, parietal
+bone; 6, frontal bone; 7, orbital process; 8, orbital cavity; 9,
+external auditory canal, in front of which is found the zygomatic
+process; 10, tympanic bulla; 11, superior maxillary bone; 12,
+intermaxillary or incisor bone; 13, nasal bone; 14, anterior opening of
+the cavity of the nasal fossae; 15, malar bone; 16, lachrymal bone; 17,
+inferior maxillary bone; 18, condyle of the inferior maxillary bone; 19,
+coronoid process; 20, incisor teeth; 21, canine teeth; 22, molar teeth.]
+
+In the carnivora, these crests are situated, throughout their whole
+length, in the median line, the temporal fossae being, accordingly, as
+extended as they possibly can be. In certain species, the development of
+these crests is such that they form by their union a vertical plate,
+which, in separating the two temporal fossae, gives them a greater depth.
+In the pig, the parietal crests, analogous in this respect to the
+temporal curved lines of the parietal bones of man, are separated by an
+interval, proportionately less extended, however, than that of the human
+skull. The parietal bone in the ox and the sheep does not enter into the
+formation of the anterior surface of the skull; it is formed by an
+osseous plate, narrow and elongated transversely, which, with the
+occipital bone, constitutes the base of the region of _the nape of the
+neck_. It is bent upon itself at the level of its lateral portions so as
+to occupy the temporal fossa.
+
+The anterior surface of the frontal bone, which is depressed in the
+median line in the dog, but plane in the horse, is limited by two
+crests, which, situated on the prolongation of the parietal crests,
+diverge more and more from one another in proportion as they occupy a
+lower position. This surface terminates externally in two processes,
+which are the homologues of the external orbital processes of the human
+frontal bone.
+
+The superior border of these orbital processes, situated on the
+prolongation of the corresponding parietal crests, contributes to limit
+the temporal fossa. Each of these orbital processes terminates in the
+following manner: In the bear, dog, cat, and pig, in which the orbital
+cavities are incompletely bounded by bone, this process, slightly
+developed, is not in connection, by its inferior extremity, with any
+other part of the skeleton of the region. In the ox and the sheep, it
+articulates with a process of the malar bone. In the horse, it
+articulates with the zygomatic process of the temporal bone. The
+inferior margin of this process forms a part of the boundary of the
+anterior opening of the orbital cavity.
+
+The supra-orbital foramen, which does not exist in carnivora, occupies
+in the horse the base of the orbital process. In the ox, it is situated
+a little nearer the middle line; and its anterior orifice opens into an
+osseous gutter which is directed upwards towards the base of the horn,
+while inferiorly it meets the inferior border of the frontal bone; in
+the sheep this groove is but slightly developed. In this latter, as in
+the ox, it is the frontal bone which forms the most elevated portion of
+the skull. In fact, being bent upon itself at a certain level, its
+external surface is formed of two planes: one, posterior, which is
+inclined downwards and directed backwards; the other, anterior, is also
+inclined downwards, but with a forward obliquity. At the union of these
+planes the bone forms an elbow, on either side of which are found the
+osseous processes on which the horns are mounted.
+
+[Illustration: FIG. 61.--SKULL OF THE PIG: LEFT LATERAL ASPECT.
+
+1, Occipital bone; 2, condyle of the occipital; 3, jugular process; 4,
+parietal bone; 5, parietal crests; 6, frontal bone; 7, orbital process;
+8, orbital cavity; 9, external auditory canal; 10, zygomatic process;
+11, superior maxillary bone; 12, intermaxillary or incisor bone; 13,
+nasal bone; 14, anterior orifice of the cavity of the nasal fossae; 15,
+malar bone; 16, lachrymal bone; 17, inferior maxillary bone; 18, condyle
+of the inferior maxillary bone; 19, incisor teeth; 20, canine teeth; 21,
+molar teeth.]
+
+In the bear, the anterior margin of the frontal bone is prolonged by two
+small tongues of bone, which, descending on the lateral borders of the
+nasal bones, articulate with the superior half of the latter.
+
+The temporal bone is, as in man, furnished with a squamous portion,
+from which springs the zygomatic process, which is directed towards the
+face, to terminate in the following manner: in the carnivora, the pig,
+and ruminants, it articulates with the malar bone by its inferior
+border; in the horse, it insinuates itself as a sort of wedge between
+the malar bone and the orbital process of the frontal bone, with which
+it articulates, as we have already pointed out, and contributes, by a
+portion situated in front of this articulation, to form the boundary of
+the anterior opening of the corresponding orbital cavity. As in man, the
+zygomatic process arises by two roots: one, transverse, behind which is
+situated the glenoid cavity of the temporal bone; the other,
+antero-posterior, which proceeds to join above with the superior curved
+line of the occipital bone.
+
+Behind the glenoid cavity is found the external auditory canal, and,
+further back still, the mastoid process. This latter, but slightly
+developed in the carnivora, a little more so in the ruminants, and still
+more in the horse, has its external surface traversed by a crest, _the
+mastoid crest_, which, after becoming blended with the antero-posterior
+root of the zygomatic process, proceeds with this latter to join the
+superior occipital curved line.
+
+Below the auditory canal is situated a round prominence, highly
+developed in carnivora; this is _the tympanic bulla_, also called _the
+mastoid protuberance_; it is an appendage of the tympanum.
+
+
+The Face
+
+The bone of this region, around which all the others come to be grouped,
+is, as in man, the superior maxillary. The relations of this maxillary
+with the neighbouring bones is not exactly the same in all animals; for
+example, in the ox, sheep, and horse, in which the bones of the nose are
+wide in their upper part, and in which the lachrymal bone, which is very
+highly developed, encroaches on the face, the superior maxillary does
+not meet the frontal bone; it is separated from it by the above-named
+bones. It unites with it, on the other hand, in the dog and the cat. In
+the bear, it is separated from the bones of the nose by a small tongue
+of bone which springs from the anterior border of the frontal--a
+process which we have noticed in connection with this latter.
+
+[Illustration: FIG. 62.--THE SKULL OF THE OX: LEFT LATERAL ASPECT.
+
+1, Occipital condyle; 2, jugular process; 3, parietal bone; 4, frontal
+bone; 5, osseous process, which serves to support the horn (horn-core);
+6, orbital cavity; 7, external auditory canal, in front of which is
+found the zygomatic process; 8, temporal fossa; 9, superior maxillary
+bone; 10, intermaxillary or incisor bone; 11, nasal bone; 12, anterior
+orifice of the cavity of the nasal fossae; 13, malar bone; 14, lachrymal
+bone; 15, inferior maxillary bone; 16, condyle of the inferior maxillary
+bone; 17, incisor teeth; 18, molar teeth.]
+
+In the pig, ox, sheep, and horse, the external surface is traversed, to
+a greater or less extent, by a crest which is situated on the
+prolongation of the inferior border of the malar bone. This crest, which
+is straight in the horse, but curved with its convexity upwards in the
+ox and the sheep, is known as _the maxillary spine_ or _the malar
+tuberosity_: it gives attachment to the masseter muscle, and, in the
+horse, is distinctly visible under the skin. It does not exist in the
+carnivora. On the same surface is situated the sub-orbital foramen.
+
+The inferior border is hollowed out into alveoli, in which are implanted
+the superior molar and canine teeth. This border is prolonged forwards
+from the alveolus, which corresponds to the first molar tooth, to
+terminate, after a course more or less prolonged, at the alveolus of the
+canine. This space, more or less considerably expanded, which thus
+separates these teeth is called the _interdental space_; but this
+denomination is not applicable to ruminants, because these latter
+possess neither canine nor incisor teeth in the upper jaw (see p. 125,
+dentition of the ox and sheep). The superior maxillary bone of one side
+and that of the opposite side do not meet in the median line in the
+region which corresponds to the incisor teeth; they are separated by a
+bone which, in the human species, is present only at the commencement of
+life, and afterwards coalesces with the maxilla; this is the
+intermaxillary or incisor bone. This bone, which is paired, is formed of
+a central part, which bears the superior incisor teeth; it is prolonged
+upwards and backwards by two processes: one, external, which insinuates
+itself between the superior maxillary and the nasal bone, except in the
+sheep, in which it remains widely separated from the latter; the other,
+internal, which is united to that which belongs to the bone of the
+opposite side to form part of the floor of the cavity of the nasal
+fossae; the external border of this process, which is separated from the
+body of the bone by a notch, forms the internal boundary of the
+corresponding _incisor opening_ or the _incisor slit_. Owing to the
+absence of superior incisors in ruminants, the intermaxillary bone
+presents no alveoli.
+
+The malar bone, and the os unguis or lachrymal, are more or less
+developed according to the species considered. With regard to the malar
+bone, it is most important to notice the part which it takes in the
+formation of the zygomatic arch, and that its inferior border
+contributes to form the crest to which is attached the masseter muscle.
+
+As for the nasal bones, they present differential characters which, as
+they affect the form of the region which they occupy, are worthy of
+notice.
+
+[Illustration: FIG. 63.--SKULL OF THE HORSE: LEFT LATERAL ASPECT.
+
+1, Posterior surface of the occipital bone; 2, external occipital
+protuberance; 3, occipital condyle; 4, jugular process; 5, parietal
+bone; 6, frontal bone; 7, orbital cavity; 8, zygomatic process of the
+temporal bone; 9, external auditory canal; 10, mastoid process; 11,
+superior maxillary bone or _maxilla_; 12, intermaxillary or incisor
+bone; 13, nasal bone; 14, anterior orifice of the cavity of the nasal
+fossae; 14', malar bone; 15, lachrymal bone; 16, inferior maxillary bone
+or _mandible_; 17, inferior maxillary fissure; 18, condyle of the
+inferior maxillary bone; 19, coronoid process of the inferior maxillary
+bone; 20, incisor teeth; 21, canine teeth; 22, molar teeth.]
+
+Their dimensions in length are proportional to those of the face. Very
+small in man, they are more developed in carnivora. We recognise in the
+latter the two curves which characterize them in the human species, and
+which we clearly notice when we view them on one of their lateral
+aspects: a concavity above, and a convexity below. These curves are more
+or less accentuated--very strongly marked in the bulldog, and scarcely
+at all in the greyhound. Moreover, in the carnivora also the nasal bones
+are wider below than above, and form, by their junction, a semicircular
+notch which limits, in its superior portion, the anterior opening of the
+cavity of the nasal fossae. In the horse they present an opposite
+arrangement with regard to their dimensions in width; broad above, each
+terminates below by forming a pointed process which, separated from the
+intermaxillary bones, is prolonged in front of the nasal orifice.
+
+The inferior maxillary bone is, as in man, formed of a body and two
+branches. But among the many special characteristics of form and size
+which sharply differentiate it from the human bone, one detail must be
+indicated; this is the absence of a mental prominence. Hence it results
+that the anterior border of the body of the lower jaw, instead of being
+directed obliquely downwards and forwards, is, on the contrary, oblique
+downwards and backwards, and that in certain animals this border is
+actually found almost exactly on the prolongation of the inferior border
+of the body of the bone.
+
+On the external surface of the body are found the three mental foramina.
+The superior border is hollowed out by alveoli.
+
+With regard to the branches (_rami_), they terminate in two processes:
+one, the posterior, is the condyle; the other, situated more forwards,
+is the coronoid process, which gives insertion to the temporal muscle.
+These two processes are separated by the sigmoid notch.
+
+For reasons which we will explain further on (see p. 127, movements of
+the lower jaw), the condyle presents differences of form. In the
+carnivora, it is strongly convex from before backwards, expanded
+transversely, and firmly mortised in the glenoid cavity of the temporal
+bone; in the ruminants, it is less convex from before backwards, it is
+more slightly concave in the transverse direction; in the rodents--we
+give as an example the hare (Fig. 64)--the condyle is still convex from
+before backwards, but it is flattened from without inwards.
+
+In the animals in which the muscles of mastication are very highly
+developed, and especially in the carnivora, the osseous regions occupied
+by these muscles are more extensive and more deep than in the human
+species. The length of the coronoid process, the depth of the temporal
+fossa, the extent of the zygomatic arch, the appearance of the external
+surface of each of the rami of the lower jaw, deeply hollowed out for
+accommodation of the masseter, and to provide extensive surfaces of
+insertion for this muscle, are sure proofs furnished by the skeleton of
+the occasionally enormous development of the muscles of mastication.
+
+In the carnivora, a rather strong process, which is directed backwards,
+occupies the angle of the inferior maxilla; it is, accordingly, situated
+below the region of the condyle.
+
+[Illustration: FIG. 64.--SKULL OF THE HARE: LEFT LATERAL ASPECT.
+
+1, External occipital protuberance; 2, occipital condyle; 3, parietal
+bone; 4, frontal bone; 5, orbital process; 6, orbital cavity; 7,
+zygomatic process; 8, external auditory canal; 9, superior maxillary
+bone; 10, intermaxillary or incisor bone; 11, nasal bone; 12, anterior
+opening of the nasal fossa; 13, malar bone; 14, inferior maxillary bone;
+15, condyle of the inferior maxillary bone; 16, incisor teeth; 17, molar
+teeth.]
+
+The teeth which the jaws carry vary in number, and even in appearance,
+according to species; it is useful to note their differences. In order
+to establish the nature of these latter more effectively, we will first
+recall the fact that in man the teeth, thirty-two in number, are equally
+distributed between the jaws, and are divided into incisors, canines,
+and molars, of which the arrangement is thus formulated:
+
+  5_m._  1_c._  2_i._ | 2_i._  1_c._  5_m._
+  --------------------+-------------------- = 32.[19]
+  5_m._  1_c._  2_i._ | 2_i._  1_c._  5_m._
+
+  [19] _I.e._, _i_, incisors; _c_, canines; _m_, molars.
+
+We also note that the incisors are edged, the canines are pointed, and
+that the molars, cubical in shape, have their surface of contact
+provided with tubercles.
+
+The teeth of the cat are thirty in number; they are thus arranged:
+
+  4_m._  1_c._  3_i._ | 3_i._  1_c._  4_m._
+  --------------------+-------------------- = 30.
+  3_m._  1_c._  3_i._ | 3_i._  1_c._  3_m._
+
+Those of the dog number forty-two:
+
+  6_m._  1_c._  3_i._ | 3_i._  1_c._  6_m._
+  --------------------+-------------------- = 42.
+  7_m._  1_c._  3_i._ | 3_i._  1_c._  7_m._
+
+In these animals, the incisors, such as are not damaged by use, are
+furnished, on the free border of their crown, with three tubercles, of
+which one, the median, is more developed than those which are situated
+laterally. We denote these teeth, commencing with those nearest the
+median line, by the names _central incisors_ or _nippers_,
+_intermediate_ and _corner incisors_. The canines, or _fangs_, are long
+and conical; they are curved backwards and outwards. The upper canines,
+which are larger than those of the lower jaw, are separated from the
+most external of the incisors (_corner_) by an interval in which the
+canines of the lower jaw are received. The lower canines, on the other
+hand, are in contact with the neighbouring incisors, and are each
+separated from the first molar which succeeds them by a wider interval
+than that which is situated between the corresponding teeth in the upper
+jaw.
+
+The molars differ essentially from the teeth of the same class in the
+human species. Their crown terminates in a cutting border bristling with
+sharp-pointed projections; this formation indicates that these teeth are
+principally designed for tearing. During the movement of raising the
+lower jaw, which is so energetic in the carnivora, they act, indeed, in
+the same manner as the two blades of a pair of scissors. The largest
+molars are: in the dog, the fourth of the upper jaw, and the fifth in
+the opposite one; in the cat, the third both above and below.
+
+The pig has forty-four teeth disposed in the following manner:
+
+  7_m._  1_c._  3_i._ | 3_i._  1_c._  7_m._
+  --------------------+-------------------- = 44.
+  7_m._  1_c._  3_i._ | 3_i._  1_c._  7_m._
+
+Of the incisors, the nippers and the intermediate ones of the upper jaw
+have their analogues in those of the horse; in the lower jaw, the
+corresponding teeth, straight, and directed forward, rather resemble the
+same incisors in rodents. The corner incisor teeth are much smaller, and
+are separated from the neighbouring teeth. The canine teeth, also called
+_tusks_ or _tushes_, are greatly developed, especially in the male. The
+molars increase in size from the first to the last; they are not
+cutting, as in the carnivora, but they are not flattened and provided
+with tubercles on their surfaces of contact as in the herbivora.
+
+In the ox and the sheep the teeth are thirty-two in number:
+
+  6_m._  0_c._  0_i._ | 0_i._  0_c._  6_m._
+  --------------------+-------------------- = 32.
+  6_m._  0_c._  4_i._ | 4_i._  0_c._  6_m._
+
+As we see from this dental formula, the incisors are found only in the
+lower jaw; they are replaced in the upper jaw by a thick cartilaginous
+pad on which the inferior incisors find a surface of resistance.
+
+These have their crowns flattened from above downwards, and gradually
+become thinner from the root to the anterior border, which is edged and
+slightly convex. These teeth gradually wear away. In proportion to the
+progress of this wear, on account of the fact that it involves the
+anterior borders and upper surfaces of the incisor teeth, and that these
+teeth are narrower towards the root than at the opposite extremity, the
+intervals which separate them tend to become wider and wider; and when
+the roots become exposed by the retraction of the gums, they are then
+separated from one another by a considerable interval. The molars have
+their grinding surface comparable to that of the horse; they increase in
+size from the first to the sixth.
+
+The teeth of the horse are forty in number; they are thus distributed:
+
+  6_m._  1_c._  3_i._ | 3_i._  1_c._  6_m._
+  --------------------+-------------------- = 40.
+  6_m._  1_c._  3_i._ | 3_i._  1_c._  6_m._
+
+As they become worn, these teeth continue to grow, and as, on the one
+hand, this phenomenon takes place throughout the whole life of the
+animal, and, on the other hand, the process of wear brings out and makes
+visible at the surface of friction parts formerly deeper and deeper, and
+of which the configuration varies at different levels, there result
+special features which permit the determination of the age of the animal
+by an examination of its jaws. The incisors are called, commencing with
+those situated nearest the middle line, _central incisors_ or _nippers_,
+_intermediate_ and _corner incisors_. The canines, also designated as
+the _fangs_, exist only in the male. It is exceptional to find them in
+the mare, and when they exist in this latter they are less developed
+than those of the horse. The molars have cuboid crowns; the surface of
+friction is almost square in the case of the upper molars, and is
+inclined so as to look inwards; in the case of the inferior ones, it is
+a little narrowed, and is inclined so as to look outwards. In the upper
+jaw the external surface of the crown is hollowed by two longitudinal
+furrows; in the lower jaw the same surface has only one furrow, which at
+times is but slightly marked.
+
+In the hare the teeth are twenty-eight in number:
+
+  6_m._  0_c._  2_i._ | 2_i._  0_c._  6_m._
+  --------------------+-------------------- = 28.
+  5_m._  0_c._  1_i._ | 1_i._  0_c._  5_m._
+
+The four incisors of the upper jaw are divided into two groups; one of
+these is formed by the two principal teeth, the other by two very small
+incisors which are placed behind the preceding.
+
+Having studied the jaws and examined the arrangement of the teeth, we
+should say a few words on the movements which the lower jaw is able to
+execute. In man, these movements are varied in character: the jaw is
+lowered and raised; it can also be projected forwards and drawn
+backwards, or carried to the right or left side by lateral movements.
+Owing to the different modes of nutrition of animals, with which the
+shape of the teeth is clearly correlated, being more specialized than in
+the human species, the lower jaw is moved in a fashion less varied and
+in the direction most suitable for the mastication of the foods which
+form the aliment of the species considered. Moreover, this is plainly
+shown in the skeleton by the shape of the condyle of the lower jaw (see
+p. 122, different forms of this condyle). In the carnivora, whose teeth,
+as we have seen, are all cutting ones, the jaw rises and falls; the food
+then is, if we consider the two jaws, cut as by the blades of a pair of
+scissors. In the ruminants, the incisors exist only in the lower jaw,
+but the molars are thick and well developed; the food is ground by these
+latter as by millstones, and the movements which favour this action are,
+above all, the lateral. As for the rodents, in which the incisors are
+formed for filing down and cutting through hard resisting bodies, their
+lower jaw moves in the antero-posterior direction, in such a way that
+the inferior incisors alternately advance and recede beneath those of
+the upper jaw. The free cutting border of these teeth effectively
+fulfils the function to which they are destined; their constant wear
+preserves and revivifies the chisel edge which characterizes them,
+without leading to their destruction, for the incisors in rodents are of
+continuous growth.
+
+
+THE SKULL OF BIRDS
+
+=The Skull of Birds= (Fig. 65).--If, because it is less important from
+the artistic point of view, we do not consider it necessary to describe
+in detail the skull of birds, we yet think it useful to indicate, in
+their general lines, the peculiarities it presents.
+
+In this group the skull is generally pear-shaped; to the cranium, of
+which the bones are arranged in such a way as to give it a form more or
+less spherical, succeeds a face more or less elongated, according as the
+bill is more or less developed.
+
+In general, the bones of the skull coalesce very early, with the result
+that it is only in very young individuals that we can determine their
+presence.
+
+We find the skull to consist of an occipital bone, two parietals, a
+frontal, etc.; we will indicate but one detail in connection with these
+bones: it is the presence of a single condyle for the articulation of
+the occipital bone with the atlas. We also note the quadrate bone, which
+is situated on the lateral part of the cranium, is movable on this
+latter, and acts as an intermediary between it, the bones of the face,
+and the lower jaw. The quadrate bone is regarded as a detached portion
+of the temporal; on the signification of this we do not now propose to
+dwell.
+
+[Illustration: FIG. 65.--SKULL OF THE COCK: LEFT LATERAL SURFACE.
+
+1, Occipital bone; 2, parietal bone; 3, frontal bone; 4, ethmoid bone;
+5, cavity of the tympanum; 6, quadrate bone; 7, superior maxillary bone;
+8, malar bone; 9, nasal bone; 10, 10, intermaxillary bone; 11, nasal
+orifice; 12, os unguis or lachrymal bone; 13, inferior maxillary bone.]
+
+On the anterior portion of the face we find the nasal bones, which,
+articulating with the frontal on one side, circumscribe, on the other,
+the posterior border of the nares. The nasal bone of the one side is
+separated from that of the opposite by the intermaxillary or
+premaxillary bone, which forms the skeleton of the superior mandible.
+
+The superior maxillaries, which are rudimentary, are situated on the
+lateral parts, and prolonged backward by an osseous style which
+articulates with the quadrate bone; this styloid bone, the homologue of
+the malar, is designated by certain authors as the _jugal_ or
+_quadrato-jugal_ bone.
+
+It is with the quadrate bone also that the inferior maxillary
+articulates.
+
+
+
+
+CHAPTER II
+
+MYOLOGY
+
+
+The first point to decide in commencing this study is the order in which
+we shall consider the different muscles which we have to examine. It
+must not be forgotten that in the present work we compare the
+organization of animals with that of man, which we already know, and
+that it is on the construction of this latter that, in these studies,
+the thought must at each instant be carried back in order to establish
+this comparison. Now, the general tendency which we notice in our
+teaching of anatomy, when one regards the region of the trunk in the
+human figure (a living model or a figure in the round), is first to
+consider the anterior aspect. It is the latter that, for this reason, we
+study at the very beginning; we next deal with the posterior surface of
+the trunk, because it is opposite; lastly, the lateral surfaces, because
+they unite with the preceding surfaces, the one to the other.
+
+In studying an animal, it is usually by one of its lateral aspects that
+one first observes it; it is, in fact, by these aspects that it presents
+its greatest dimensions, and that the morphological characters as a
+whole can be more readily appreciated. Hence, possibly, the order of
+description adopted in most texts, or in the figures which accompany
+them. The first representation of the human figure as a whole, in a
+treatise on anatomy, represents the anterior aspect; the first view of
+the horse as a whole, in a treatise on veterinary anatomy, for example,
+is, on the other hand, a lateral view.
+
+We break with this latter custom, and, without taking into account the
+tendency above indicated, we will commence our analysis with the study
+of the aspect of the trunk, which corresponds to the anterior aspect of
+the same region in man.
+
+The first muscles usually presented for study to artists being the
+pectorals, it is their homologues that we will first describe here. We
+will afterwards describe the abdominal region, then the muscles which
+occupy the dorsal aspect of the trunk. With regard to the lateral
+surfaces, they will be found, by this fact alone, almost completely
+studied, since the muscles of the two preceding (back and abdomen),
+spreading out, so to speak, over them, contribute to their formation.
+Nothing further will remain but to incorporate with them the muscles of
+the shoulder; but these will be studied in connection with the anterior
+limbs, from which they cannot be separated.
+
+The neck, in man, may be considered in an isolated fashion, because, on
+account of its narrowness in proportion to the width of the shoulders,
+it is clearly differentiated from the trunk; for this reason we combine
+the study of it with that of the head. In animals, because of the
+absence or slight development of the clavicles, the neck is generally
+too much confounded with the region of the shoulders to make it
+legitimate to separate it from that region in too marked a fashion. It
+will, accordingly, be considered next.
+
+We will then undertake the study of the muscles of the limbs, and end
+with the myology of the head.
+
+
+THE MUSCLES OF THE TRUNK
+
+We shall divide them into muscles of the thorax, of the abdomen, and of
+the back.
+
+
+Muscles of the Thorax
+
+=The Pectoralis Major= (Fig. 66, 1, 2; Fig. 67, 3, 4; Fig. 68, 7; Fig.
+69, 10; Fig. 70, 11).--Further designated by the name of _superficial
+pectoral_, this muscle is described in treatises on veterinary anatomy
+as formed of two portions: an anterior one, called the _sterno-humeral_
+muscle; the other, situated below and behind the preceding, bearing the
+name of _sterno-aponeurotic_.
+
+It occupies the region of the breast, and, as a whole, it takes origin
+from the median portion of the sternum, from which it is directed
+towards the arm and forearm.
+
+The anterior portion (sterno-humeral muscle)--thick, forming an
+elevation under the skin, and really constituting the pectoral
+region--is directed downwards and outwards to be inserted into the
+anterior margin of the humerus--that is to say, to the ridge which
+limits in front the spiral groove of this bone.
+
+The other part (sterno-aponeurotic muscle) is situated more posteriorly,
+and corresponds to the region known in veterinary anatomy as the
+_inter-fore-limb space_, which is limited laterally on each side by the
+superior portion of the forearm, of which the point of junction with the
+trunk bears the name _ars_. Arising from the sternum, as we have above
+indicated, this portion is directed outwards, to be joined with the
+terminal aponeurosis of the sterno-humeral, and with that which covers
+the internal surface of the forearm.
+
+All things considered, the sterno-humeral muscle may be regarded as the
+representative of the upper fibres of the great pectoral of man, of
+which the attachments, owing to the more or less complete absence of the
+clavicle in the domestic mammals, the fibres must be concentrated on
+the sternum; the sterno-aponeurotic portion then representing the
+inferior fasciculae of the same muscle.
+
+[Illustration: FIG. 66.--MYOLOGY OF THE HORSE: ANTERIOR ASPECT OF THE
+TRUNK.
+
+1, Pectoralis major (sterno-humeral); 2, pectoralis major
+(sterno-aponeurotic); 3, mastoido-humeralis; 4, point of the shoulder;
+5, sterno-mastoid or sterno-maxillary: 6, inferior portion of the
+platysma myoides of the neck, divided; 7, triceps cubiti; 8, brachialis
+anticus; 9, radialis (anterior extensor of the metacarpus); 10, scapular
+region.]
+
+The great pectoral muscle of one side is separated from that of the
+opposite side along the median line, and especially above and in front,
+by a groove which is more or less deep, according as the muscles are
+more or less developed. At the bottom of this groove, suggestive of that
+which exists in the corresponding region in man, is found, as in this
+latter, the median portion of the sternum.
+
+The preceding description particularly applies to the arrangement which
+the great pectoral presents in the horse; in other animals it is marked
+by some distinctive characters. In the pig, it is inserted into the
+sternum as far only as the level of the third costal cartilage; in the
+ox and sheep, it extends as far as the sixth; in the dog, it is
+attached to the two first sternal pieces only--that is to say, as far as
+the third costal cartilage. Moreover, in the latter, as in the cat, the
+two portions which we have indicated are less readily distinguished.
+
+The great pectoral, by its contraction, draws the fore-limb towards the
+middle line--that is to say, adducts it.
+
+=The Pectoralis Minor= (Fig. 67, 6; Fig. 68, 8; Fig. 69, 11; Fig. 70,
+12, 26).--This muscle, also called the _deep pectoral_, is, in animals,
+larger than the superficial pectoral, therefore certain authors prefer
+to give to this muscle and the preceding one the names of deep and
+superficial pectoral respectively. This nomenclature is evidently
+legitimate, and conforms more to reality, since it does not bring in the
+notion of dimensions which here is found in contradiction to
+nomenclature; but, in order to establish more clearly the parallelism
+with the corresponding muscles in man, we think it better, nevertheless,
+to give them the names by which it has been customary to designate them
+in connection with the latter.
+
+We will recall at the outset that the lesser pectoral muscle in man is
+completely covered by the great. In animals this is not the case; the
+lesser pectoral being very highly developed, projects beyond the great
+pectoral posteriorly, and occupies to a greater or less extent the
+inferior surface of the abdomen.
+
+It also consists of two parts: one anterior, which we designate by the
+name of _sterno-prescapular_; the other, posterior, bearing that of
+_sterno-humeral_.[20]
+
+  [20] This division of the pectorals certainly complicates the
+       nomenclature of these muscles; nevertheless, it introduces no
+       insuperable difficulty from the mnemonic point of view. But where
+       the study becomes less profitable, and comparison with the
+       corresponding muscles in man more complicated, is in adopting the
+       nomenclature of Bourgelat. Indeed, the great pectoral is
+       designated by this author the 'common muscle of the arm and
+       forearm,' while the lesser pectoral (or deep pectoral) is called
+       the 'great pectoral' in its sterno-trochinian and 'lesser
+       pectoral' in its sterno-prescapular portion. We do not consider
+       it necessary to give the other theories relative to the
+       homologies of these, notwithstanding the very real interest which
+       they present from the purely anatomical point of view, as they
+       have but few applications in the study of forms.
+
+The sterno-prescapular muscle, being covered by the sterno-humeral, has
+little interest for us. It arises from the sternum, and is directed
+towards the angle formed by the junction of the scapula and humerus;
+then it is reflected upwards and backwards, to terminate on the anterior
+margin of the shoulder by insertion into the aponeurosis, which covers
+the supraspinatus muscle.
+
+We can, especially in the horse after removal of the skin, recognise it,
+at the level of this region, in the interspace limited by the
+superficial muscles (Fig. 70, 26).
+
+In the dog and cat this portion of the muscle does not exist. The other
+division of the muscle, the sterno-trochinian, is more interesting. It
+arises from the abdominal aponeurosis and the posterior part of the
+sternum; hence it passes forward, turns under the superficial pectoral,
+and is inserted into the lesser tuberosity (trochin) of the humerus.
+
+In the pig, dog, and cat, it is inserted into the greater tuberosity
+(trochiter) of the bone of the arm.
+
+The superior border of this muscle is in relation with a superficial
+vein, which is distinctly visible in the horse--the subcutaneous
+thoracic vein, which in this animal is called the vein of the spur.
+
+The sterno-humeral muscle, in contracting, draws the shoulder and the
+whole anterior limb backwards.
+
+=Serratus Magnus= (Fig. 67, 2; Fig. 69, 8; Fig. 70, 9).--This muscle,
+which is situated on the lateral aspect of the thorax, is covered to a
+considerable extent by the shoulder, the posterior muscular mass of the
+arm, and by the great dorsal muscle.
+
+It arises by digitations from the external surface of the dorsal
+vertebrae; from the first eight in the horse, ox, and dog.
+
+[Illustration: FIG. 67.--MYOLOGY OF THE HORSE: INFERIOR ASPECT OF THE
+TRUNK.
+
+1, Anterior extremity of the sternum; 2, point of the shoulder and
+inferior portion of the mastoido-humeral muscle; 3, pectoralis major
+(sterno-humeral); 4, pectoralis major (sterno-aponeurotic); 5, point of
+the elbow; 6, pectoralis minor (sterno-trochinian); 7, serratus magnus;
+8, external oblique; 9, sheath of the rectus abdominis; 10, linea alba;
+11, the umbilicus; 12, external oblique divided in order to expose the
+rectus abdominis; 13, rectus abdominis.]
+
+The muscular bundles, converging as they proceed, towards the scapula,
+pass under this bone, to be inserted into the superior portion of the
+subscapular fossa, near the spinal border. The inferior portion of its
+posterior digitations is visible in the ox and in the horse; these
+digitations are less visible in the pig. They are not seen at all in the
+dog (Fig. 68) or cat, for in these animals the great dorsal muscle
+covers them completely.
+
+The great serratus muscle, by the position which it occupies and the
+arrangement that it presents, forms with the corresponding muscle of the
+opposite side a sort of girth, which supports the thorax, and at the
+same time helps to fix the scapula against the latter.
+
+When it contracts, in taking its fixed point at the ribs, it draws the
+superior portion of the scapula downwards and backwards in such a way
+that this bone has its inferior angle directed forwards and upwards. If
+it takes its fixed point at the shoulder, it then acts on the ribs,
+raises them, and so becomes a muscle of inspiration.
+
+Because of the connections of the serratus magnus with the levator
+anguli scapulae, some authors consider it as united with the latter. But
+as the latter muscle is visible only in the region of the neck (see p.
+157), and as it is separately described in man, we prefer to distinguish
+them from one another. We shall recall the connections to which we have
+just made allusion when describing the cervical region.
+
+
+Muscles of the Abdomen
+
+The abdominal wall is, as in man, formed by four large muscles: the
+external oblique, the internal oblique, and the transversalis, which
+form the lateral walls, and the rectus abdominis, situated on each side
+of the middle line of the abdomen. This latter, because of the general
+direction of the trunk in quadrupeds, has its superficial surface
+directed downwards.
+
+The arrangement of these muscles closely corresponds to that which we
+find in the human species.
+
+=The External Oblique Muscle= (Fig. 67, 8, 12; Fig. 68, 5; Fig. 69, 9;
+Fig. 70, 10).--This muscle arises, by digitations, from a number of
+ribs, which varies according to the species, the number of the ribs
+being itself variable for each of them, as we pointed out in connection
+with the osteology of the thorax. Indeed, the great oblique arises from
+the eight or nine posterior ribs in the dog and the ox, and from the
+thirteen or fourteen posterior in the horse. It is attached, besides, to
+the dorso-lumbar aponeurosis.
+
+These attachments are arranged in a line directed obliquely upwards and
+backwards, and the first digitations--that is to say, the most anterior
+ones--dovetail with the posterior digitations of origin of the great
+serratus muscle.
+
+The fleshy fibres are directed downwards and backwards, and terminate in
+an aponeurosis which covers the inferior aspect of the abdomen, and
+proceeds to form the linea alba by joining with that of the muscle of
+the opposite side, and also to be inserted into the crural arch.
+
+This aponeurosis of the external oblique is covered by an expansion of
+elastic fibrous tissue, which doubles it externally, and which is known
+as the _abdominal tunic_. This latter is further developed as the organs
+of the digestive apparatus are more voluminous, and their weight,
+consequently, more considerable. For this reason, in the large
+herbivora, as the ox and the horse, this tunic is extremely thick,
+whereas in the pig, cat, and dog it is, on the contrary, reduced to a
+simple membrane. Indeed, in these latter, the abdominal viscera being
+less developed, the inferior wall of the abdomen does not require so
+strong a fibrous apparatus for supporting them. The great oblique, when
+it contracts, compresses the abdominal viscera in all circumstances
+under which this compression is necessary; it also acts as a flexor of
+the vertebral column.
+
+=The Internal Oblique Muscle.=--This muscle, which is covered by the
+preceding, arises from the anterior superior iliac spine (external angle
+in ruminants and solipeds) and the neighbouring parts. From this origin
+its muscular fibres, the general direction of which is opposite to that
+of the fibres of the external oblique, diverging, proceed to terminate
+in an aponeurosis, which contributes to the formation of the _linea
+alba_, and to be attached superiorly to the internal surface of the last
+costal cartilages. It has the same action as the great oblique. What it
+presents of special interest is the detail of form which it determines
+in the region of the flank; this detail is _the cord of the flank_. It
+is characterized by an elongated prominence which, starting from the
+iliac spine, is directed obliquely downwards and forwards, to terminate
+near the cartilaginous border of the false ribs.
+
+Often very apparent in the ox, and still more so in the cow, the cord in
+question contrasts with the depression which surmounts it; this
+depression is situated below the costiform processes of the lumbar
+vertebrae, and is called the _hollow of the flank_. It is so much the
+more marked as the mass of the intestinal viscera is of greater weight.
+
+We sometimes meet with a case of the presence of this hollow in the
+horse. But when in the latter, the flank is well formed, the hollow is
+scarcely visible, and the cord but slightly prominent. It is only in
+emaciated subjects that these details are found clearly marked.
+
+=Transversalis Abdominis.=--This muscle being deeply situated does not
+present any interest for us. We will, however, point out, in order to
+complete the series of muscles which form the abdominal wall, that the
+direction of its fibres is transverse, and that they extend from the
+internal surface of the cartilages of the false ribs, and the costiform
+processes of the lumbar vertebrae to the _linea alba_.
+
+=The Rectus Abdominis= (Fig. 67, 13; Fig. 68, 6).--This muscle,
+enclosed, as it is in man, in a fibrous sheath (Fig. 67, 9) formed by
+the aponeuroses of the lateral muscles of the abdomen, is a long and
+wide fleshy band, which, as in the human species, reaches from the
+thorax to the pubis.
+
+What distinguishes it in quadrupeds is that there are costal attachments
+which extend further on the sternal surface of the thorax, and the
+number of its aponeurotic insertions, which, in general, is more
+considerable. These are, indeed, six or seven in number in the pig and
+in ruminants, and about ten in the horse.
+
+It is true that we may find but three in the cat and dog; still, we
+often find as many as six. These intersections are not marked on their
+exterior by transverse grooves, such as we find in the human species in
+individuals with delicate skin and whose adipose tissue is not very much
+developed.
+
+The rectus abdominis is covered, in its anterior portion, by the
+sterno-trochinian muscle (posterior segment of the small pectoral). In
+contracting, this muscle brings the chest nearer the pelvis, and as a
+result flexes the vertebral column. It also contributes to the
+compression of the abdominal viscera.
+
+=Pyramidalis Abdominis.=--This unimportant little muscle, which in man
+is situated at the lower part of the abdomen, extends from the pubis to
+the _linea alba_. It is not present in the domestic animals.
+
+We consider it interesting, however, to point out, although the fact is
+not a very useful one as regards external form, that this muscle is
+distinctly developed in marsupials.
+
+We know that in the opossum, the kangaroo, and the phalanger fox, the
+young are brought forth in an entirely incomplete state of development,
+and that, during a certain period, they are obliged to lodge in a pouch
+which is placed at the lower part of the abdomen of the mother. Now,
+this pouch contains the mammary glands; but the young, being too feeble
+to exercise the requisite suction, the pyramidal muscles come to their
+assistance. These muscles, in contracting, approximate to one another
+two bones which are placed above the pubis, the (so-called) marsupial
+bones (see Fig. 80); by their approximation the bones in question, which
+are placed behind and on the outer side of the mammary glands, compress
+the latter, and thus is brought about the result which the little ones,
+on account of their feebleness, would, without that intervention, be
+incapable of obtaining for themselves.
+
+
+Muscles of the Back
+
+=Trapezius= (Fig. 68, 1, 2; Fig. 69, 1, 2; Fig. 70, 1, 2).--This muscle,
+more or less well developed, according to the species, is divided into
+two portions, of which the names indicate the respective situations--a
+cervical and a dorsal.
+
+These two parts, considered in the order in which we find them, take
+their origin from the superior cervical ligament and from the spinous
+processes of the first dorsal vertebrae. From these different points the
+fibres are directed towards the shoulder; the anterior are,
+consequently, oblique downwards and backwards, and the posterior are
+directed downwards and forwards. They are inserted into the scapula in
+the following manner: the fibres of the dorsal portion are attached to
+the tuberosity of the spine; those of the cervical region are also fixed
+into the same spine, but into a considerably larger surface.
+
+The cervical portion occupies, in the region of the neck, an area
+relatively smaller than the corresponding portion of the trapezius in
+man. This diminished degree of development results from the absence,
+complete, or nearly so, of the clavicle in the animals which we are now
+considering. We remember, that the trapezius of man is partly inserted
+into the clavicle, and the disappearance of this latter cannot fail to
+bring modifications in the general disposition of the corresponding
+portion of the muscle. There results a disconnection of this latter, and
+it becomes united to other muscular fibres to form a muscle with which
+we shall soon have to deal--the mastoido-humeral (see p. 150).
+
+As specific differences we should add that the trapezius occupies a more
+or less extensive portion of the median and superior regions of the
+neck; terminating at a considerable distance from the head in the dog
+and horse, it, on the contrary, approaches it in the pig and in
+ruminants. The cervical portion, when it contracts, draws the scapula
+upwards and forwards, the dorsal portion draws it upwards and backwards.
+When the trapezius acts as a whole the scapula is raised.
+
+[Illustration: FIG. 68.--MYOLOGY OF THE DOG: SUPERFICIAL LAYER OF
+MUSCLES.
+
+1, Trapezius, cervical portion; 2, trapezius, dorsal portion; 3,
+superior outline of the scapula; 4, latissimus dorsi; 5, external
+oblique muscle; 6, rectus abdominis; 7, pectoralis major of the right
+side; 8, pectoralis minor (sterno-trochinian); 9, 9, mastoido humeral
+muscle; 10, tendinous intersection, at the level of which is found a
+rudimentary clavicle; 11, sterno-mastoid muscle; 12, infrahyoid muscles;
+13, omo-tracheal or acromio-tracheal muscle; 14, splenius; 15, levator
+anguli scapulae; 16, deltoid muscle, spinal portion; 17, deltoid,
+acromial portion; 18, superior extremity of the humerus; 19,
+supraspinatus; 20, infraspinatus; 21, biceps cubiti; 22, brachialis
+anticus; 23, triceps cubiti, long head; 24, triceps cubiti, external
+head; 25, olecranon process; 26, radialis (anterior extensor of the
+metacarpus); 27, iliac crest; 28, gluteus maximus; 29, gluteus medius;
+30, biceps cruris; 31, semitendinosus; 32, semi-membranosus; 33,
+gastrocnemius; 34, tensor of the fascia lata; 35, sartorius; 36, fascia
+lata drawn up by the triceps; 37, the patella or knee-cap; 38,
+ischio-coccygeal muscle; 39, superior sacro-coccygeal; 40, lateral
+sacro-coccygeal; 41, inferior sacro-coccygeal.]
+
+=The Latissimus Dorsi= (Fig. 68, 4; Fig. 69, 5; Fig. 70, 5).--This
+muscle arises by an aponeurosis, the so-called dorso-lumbar aponeurosis,
+from the spinous processes of the last dorsal vertebrae (the seven last
+in the dog, fourteen or fifteen last in the horse), from the spinous
+processes of the lumbar vertebrae, and from the last ribs. Its fleshy
+fibres are directed downwards and forwards, being more oblique in
+direction posteriorly, and pass on the inner side of the posterior
+muscular mass of the arm, to be inserted into the internal lip of the
+bicipital groove of the humerus, or, a little lower down, on the median
+portion of the internal surface of the same bone. This latter mode of
+insertion is met with in the horse and the ox.
+
+The anterior fibres cover the posterior angle of the scapula (as in man,
+where the corresponding angle, but in this case inferior, is covered by
+the same muscle), and, a little higher up, are in their turn concealed
+by a portion of the dorsal fibres of the trapezius. It covers, to a
+greater or less extent, the great serratus muscle. These relations are
+similar to those found in the human species.
+
+We find that the fleshy fibres of the great dorsal are prolonged more or
+less backwards if we examine this muscle in the dog, the ox, the pig,
+and the horse. Indeed, the fibres reach to the thirteenth rib in the dog
+and the cat (that is to say, the last rib), the eleventh in the ox,
+tenth in the pig, and twelfth only in the horse. We say 'only' in
+connection with this last because it is necessary to remember that the
+ribs are eighteen in number on each side of the thorax of this animal,
+and that, accordingly, the fleshy fibres of the great dorsal muscle are,
+relatively, of small extent.
+
+When this muscle contracts it flexes the humerus upon the scapula, and
+helps to draw the whole of the anterior limb backwards and upwards.
+
+There is a muscular fasciculus which, because of its relations with the
+muscle we have just been studying, is known as the _supplementary muscle
+of the latissimus dorsi_. But as, on the other hand, this fasciculus is
+in relation with the triceps, we shall in preference consider it in
+relation with this latter (see p. 173).
+
+[Illustration: FIG. 69.--MYOLOGY OF THE OX: SUPERFICIAL LAYER OF
+MUSCLES.
+
+1, Trapezius, cervical portion; 2, trapezius, dorsal portion; 3, outline
+of the scapula; 4, spine of the scapula; 5, latissimus dorsi; 6, small
+posterior serratus; 7, prominence caused by the costiform processes of
+the lumbar vertebrae; 8, serratus magnus; 9, external oblique; 10,
+pectoralis major (sterno-humeral); 11, mastoido-humeralis; 12, atlas;
+13, atlas; 14, parotid gland; 15, sterno-mastoid muscle; 16, infrahyoid
+muscles; 17, omo-trachelian or acromio-trachelian muscle; 18, deltoid;
+19, brachialis anticus; 20, triceps, long head; 21, triceps, external
+head; 22, olecranon; 23, radialis (anterior extensor of the metacarpus);
+24, anterior iliac spine; 25, gluteus maximus; 26, gluteus medius; 27,
+biceps cruris; 28, semitendinosus; 29, gastrocnemius; 30, tensor of the
+fascia lata; 31, fascia lata covering the triceps of the thigh; 32,
+patella; 33, ischio-coccygeal muscle; 34, superior ischio-coccygeal; 35,
+lateral ischio-coccygeal; 36, inferior ischio-coccygeal.]
+
+The aponeurosis by which the great dorsal arises from the vertebral
+column covers, as in man, the muscles which occupy the grooves situated
+on each side of the spinous processes--the spinal muscles or common
+muscular mass, if we regard them as a whole (Fig. 70, 7); the
+sacro-lumbar and the long dorsal muscles covering the transverse spinal,
+if we consider them as distinct.
+
+It would be superfluous to enter here into a detailed examination of
+these muscles.
+
+If they are but little developed the spinous processes become prominent
+under the skin; if they are more so they may by their thickness project
+beyond the level of these processes, and these latter thus come to lie
+in a groove more or less marked, which, on account of the division which
+is determined by its presence, has caused the regions which it occupies
+to be designated by the names _double back_ and _double loins_.
+
+The muscles are extensors of the vertebral column.
+
+Under the aponeurosis of the great dorsal muscle there is found in man
+another muscle, the serratus posticus inferior, which, on account of
+being deeply placed and its slight thickness, offers nothing of interest
+in connection with the study of external form. It arises from the
+spinous processes of the three last dorsal vertebrae and those of the
+three first lumbar; it then passes upwards and outwards, and divides
+into four digitations, to be inserted into the inferior borders of the
+four last ribs. We repeat that it is covered by the great dorsal muscle.
+
+In the pig, ox, and horse, which have this latter muscle less developed
+in its posterior portion, the same small serratus muscle, known as the
+_posterior serratus_, is visible in the superficial layer of muscles
+(Fig. 69, 6; Fig. 70, 6). The number of its digitations is more or less
+considerable according to the species examined.
+
+=The Rhomboid Muscle= (Fig. 70, 21).--In order to make intelligible the
+position of the rhomboid in the superficial layer in quadrupeds, it
+appears to us necessary to recall the anatomical characters of the
+muscle as found in man. The rhomboid arises from the inferior portion of
+the posterior cervical ligament, from the spinous process of the seventh
+cervical vertebrae and the four or five upper dorsal; thence passing
+obliquely downwards and outwards, it is inserted into the spinal border
+of the scapula, into the portion of this border which is situated below
+the spine; it sometimes extends to the middle of the interval which
+separates this latter from the superior internal angle of the same bone.
+
+The portion of the muscle which arises from the cervical ligament and
+the seventh cervical vertebra is often separated from the lower portion
+by a cellular interspace. For this cause some anatomists have described
+the rhomboid as consisting of two parts--the superior or small rhomboid
+and the inferior or large rhomboid, on account of the position occupied
+by each, and of their difference in volume.
+
+This muscle can only be seen in the region of the back, in the space
+limited externally by the spinal border of the scapula, below by the
+latissimus dorsi, and internally by the trapezius, which covers it in
+the rest of its extent. It is not in this space that it is seen in
+certain quadrupeds. As we pointed out in the section on osteology, the
+spinal border of the scapula is short, and it seems to be due to this
+limitation in length that the trapezius and the latissimus dorsi muscle
+are, at this level, in contact the one with the other in such a way that
+they fill up the interval in which the rhomboid is seen in man.
+
+In the horse we can partly see it in the superficial muscular layer, but
+in the region of the neck only, at the superior border of the shoulder.
+Indeed, as we have already pointed out, the trapezius does not reach the
+occipital protuberance; for this reason a part of the anterior portion
+of the rhomboid may be seen--that is, the portion which corresponds to
+the superior part of the human muscle.
+
+But whether it be covered by the trapezius, or, as we find in the cat
+and dog, by the _mastoido-humeral muscle_ (see p. 150), which is very
+broad in this region, we do not the less recognise its presence; and in
+the horse and ox, in particular, it forms an elongated prominence
+beginning at the level of the scapula, and tapering as it ascends,
+towards the posterior part of the head.
+
+[Illustration: FIG. 70.--MYOLOGY OF THE HORSE: SUPERFICIAL LAYER OF
+MUSCLES.
+
+1, Trapezius, cervical portion; 2, trapezius, dorsal portion; 3,
+superior outline of the scapula; 4, spine of the scapula; 5,
+latissimus dorsi muscle; 6, small posterior serratus; 7, spinal muscles,
+or common muscular mass; 8, ribs; 9, serratus magnus; 10, external
+oblique; 11, pectoralis major (sterno-humeral); 12, pectoralis
+minor (sterno-trochinian); 13, atlas; 14, parotid gland; 15,
+mastoido-humeralis; 16, point of the arm; 17, sterno-mastoid, or
+sterno-maxillary; 18, jugular groove; 19, infrahyoid muscles; 20,
+omo-trachelian muscle; 21, rhomboid; 22, splenius; 23, levator anguli
+scapulae; 24, deltoid; 25, supraspinatus; 26, terminal part of the
+sterno-prescapular, a portion of the small pectoral muscle; 27,
+brachialis anticus; 28, triceps cubiti, middle or long head; 29, triceps
+cubiti, external head; 30, olecranon; 31, radial extensor (anterior
+extensor of the metacarpus); 32, anterior iliac spine; 33, anterior
+portion of the gluteus maximus--the aponeurosis of the muscle has been
+divided in order to expose the gluteus medius; 34, posterior portion of
+the gluteus maximus; 35, gluteus medius; 36, biceps cruris; 37,
+semitendinosus; 38, point of the buttock; 39, gastrocnemius; 40, tensor
+of the fascia lata; 41, triceps cruris; 42, ischio-coccygeal muscle; 43,
+superior sacro-coccygeal; 44, lateral sacro-coccygeal; 45, inferior
+sacro-coccygeal.]
+
+Its origins are similar to those which we have already described in the
+human rhomboid. It arises from the cervical ligament and the spinous
+processes of the foremost dorsal vertebrae; its fibres converge and pass
+to the scapula, to be inserted into its superior or spinal border, or
+into the internal surface of the cartilage of prolongation.
+
+It assists in keeping the scapula applied to the thoracic cage, and when
+it contracts, draws the scapula upwards and forwards.
+
+Taking its fixed point at the scapula, it acts on the neck by its
+anterior fibres, and extends it.
+
+We shall soon have occasion to mention this muscle again, in connection
+with the study of the muscles of the neck.
+
+=The Cutaneous Muscle of the Trunk= (Fig. 71).--Immediately beneath the
+skin which covers the neck, shoulders, and trunk is found a vast
+cutaneous muscle, analogous to that which, in the human species, exists
+only in the cervical region.
+
+This thin muscle, whose function is to move the skin which strongly
+adheres to it, and in this way to remove from it material causes of
+irritation (insects, for example), is of considerable thickness in the
+region of the trunk; where it constitutes what certain authors have
+designated by the name of _panniculus carnosus_. In this region it
+extends from the posterior border of the shoulder to the thigh, and, in
+the vertical direction, from the apices of the spinous process of the
+dorso-lumbar vertebrae to the median line of the abdomen.
+
+Arising above from the supraspinous ligament of the dorso-lumbar and
+sacral regions (except in the carnivora; see below) by an aponeurosis
+which, posteriorly, covers the muscles of the hind-limbs, its fibres are
+directed to the elbow, on which they are arranged in two layers: a
+superficial, which becomes continuous with the panniculus muscle of the
+shoulder; and a deep, which passes on the inner side of the shoulder to
+be inserted into the internal surface of the humerus; this latter exists
+only in the dog and cat.
+
+The most inferior fibres, behind, at the level of the knee-cap form a
+triangular process which in the horse receives the name of the _stifle
+fold_, from the name veterinarians give to the region of the
+articulation of the knee. This fold of skin, which commences on the
+antero-internal surface of this region, is directed upwards, and then
+forwards, to end by gradually disappearing over the corresponding part
+of the abdomen.
+
+[Illustration: FIG. 71.--MYOLOGY OF THE HORSE: PANNICULUS MUSCLE OF THE
+TRUNK.]
+
+In the same animal the muscular fibres of the panniculus of the trunk
+arise along a line which connects the stifle-joint to the withers, a
+line which is, consequently, oblique upwards and forwards. Now, as the
+fleshy layer is thicker than the aponeurosis, the result is that the
+mode of constitution of this muscle can be recognised under the skin.
+Indeed, we can see in some animals, occasionally very distinctly, a
+slight elevation starting from the region of the abdomen in the
+neighbourhood of the knee, and thence directed obliquely upwards and
+forwards. This elevation is produced by the fleshy portion of the
+panniculus.
+
+In the carnivora, the panniculus of the trunk is not attached to the
+supraspinous ligament; it is blended with the same muscle of the
+opposite side, passing over the spinous region of the vertebral column.
+
+From this arrangement results a great mobility of the skin which covers
+the back. Further, it explains why it is possible to lift up this skin
+along with the panniculus which it covers, and to which it adheres,
+throughout the whole extent of the dorso-lumbar column. As we pointed
+out above, there is also a panniculus muscle of the shoulder and one of
+the neck. We will deal with them when treating of the regions to which
+those muscles belong.
+
+
+The Coccygeal Region
+
+As a sequel to the study of the muscles of the region of the trunk very
+naturally comes the description of those which, belonging to the region
+of the coccyx, are destined for the movements of the caudal appendix, of
+which this latter constitutes the skeleton. The muscles may not seem to
+be of much importance with regard to external form, but, as they form
+part of the superficial muscular layer, and as the mass of each is
+seen in the form of the tail in some animals (the lion, for example),
+they merit our attention for a moment. A few lines will suffice to
+give an idea of them. They are: the _ischio-coccygeal_, _superior
+sacro-coccygeal_, _lateral sacro-coccygeal_, and _inferior
+sacro-coccygeal_.
+
+=The Ischio-coccygeal= (Fig. 18, 38; Fig. 69, 33; Fig. 70, 42).--This
+muscle, triangular in shape, better developed in the carnivora than in
+the horse, arises from the spine of the ischium, or from the
+supracotyloid crest, which replaces this latter in the solipeds and the
+ruminants. Thence its fleshy mass is directed upwards, expanding as it
+proceeds to be inserted into the transverse processes of the first two
+coccygeal vertebrae after insinuating itself between two of the following
+muscles, the lateral and inferior sacro-coccygeal.
+
+In the dog and cat, the muscle is in great part covered by the great
+gluteal. In the ox, by a peculiar arrangement of the corresponding
+region of the muscles of the thigh--an arrangement which we will examine
+in connection with the study of the latter--it is more exposed than in
+the horse, and gives origin to an outline which corresponds to its
+general form in the region situated immediately below the root of the
+tail.
+
+It is a depressor of the whole caudal appendix.
+
+=The Superior Sacro-coccygeal= (Fig. 68, 39; Fig. 69, 34; Fig. 70,
+43).--The fasciculi which form this muscle arise from the crest of the
+sacrum, and proceed thence to end successively on the coccygeal
+vertebrae. It is in contact in the middle line with the corresponding
+muscle of the opposite side.
+
+It raises the tail and inclines it laterally; if the muscle of one side
+contracts at the same time as that of the other the tail is elevated
+directly.
+
+=The Lateral Sacro-coccygeal= (Fig. 68, 40; Fig. 69, 35; Fig. 70,
+44).--Situated on the lateral part of the caudal region, this muscle
+arises, in the dog, from the internal border of the iliac bone and the
+external border of the sacrum; in the horse, it arises from the crest of
+the sacrum. It is inserted into the coccygeal vertebrae.
+
+It produces lateral movement of the tail.
+
+=The Inferior Sacro-coccygeal= (Fig. 68, 41; Fig. 69, 36; Fig. 70,
+43).--This muscle, which is fairly thick, arises from the inferior
+surface of the sacrum and the corresponding surface of the sacro-sciatic
+ligament; it is inserted into the coccygeal vertebrae.
+
+It depresses the caudal appendix.
+
+
+Muscles of the Neck
+
+=Mastoido-humeralis= (Fig. 66, 3; Fig. 68, 9, 9, 10; Fig. 69, 12; Fig.
+70, 15).--One of the most important muscles of the region of the neck in
+man is the sterno-cleido mastoid. We recollect that, in its inferior
+part, it is divided into two bundles, one of which arises from the
+manubrium of the sternum, and the other from the inner third of the
+clavicle, whence the denominations of the _sternal_ portion and
+_clavicular_ portion. The muscle formed by the union of these two
+portions is then directed obliquely outwards, backwards, and upwards, to
+be inserted into the mastoid process of the temporal bone and the two
+external thirds of the superior curved line of the occipital bone.
+
+Now, the animals which we are here considering have but a rudimentary
+clavicle or are entirely without it. From the absence of this item of
+the skeleton there necessarily result modifications in the arrangement
+of the muscles of this region, which we must at the very outset explain,
+before undertaking the special study of the muscle which is the subject
+of the present paragraph.
+
+Let us suppose, for the more definite arrangement of our ideas, that the
+clavicle is altogether absent, although we do find it in a rudimentary
+state in some animals and completely developed in others (marmot, bat),
+and we will proceed to indicate what this absence determines.
+
+The great pectoral muscle in man arises in part from the clavicle; this
+origin not being possible in animals which have no clavicle, its
+attachments, as we have already seen, are concentrated on the sternum.
+The trapezius in man similarly arises in part from the clavicle; for the
+reasons above indicated its clavicular fasciculi cannot exist in
+distinct form in the animals which have no clavicle.
+
+The sterno-cleido mastoid, whose inferior attachments we mentioned
+above, cannot have a clavicular portion.
+
+It is the same in the case of the deltoid, which, we know, arises in
+part from the anterior bone of the shoulder.
+
+Of the four muscles which have partial clavicular origins in man, two
+are known to us in connection with animals--the great pectoral and the
+trapezius. What has become of the other two, the sterno-cleido mastoid
+and the deltoid?
+
+It is this which we now proceed to investigate. After a fashion
+simple enough, but which it is necessary to describe, the clavicular
+fasciculi of the trapezius and the corresponding fasciculi of the
+sterno-cleido mastoid are united the one to the other; the portion
+of the deltoid which in man arises from the clavicle, by reason of the
+absence of this latter, is also combined with the fleshy mass formed by
+the preceding muscles. From this fusion results the muscle known as the
+mastoido-humeral. This muscle, which consists of a long fleshy band
+situated on the lateral aspect of the neck, takes its origin, as a
+general rule, from the posterior surface of the skull and the upper part
+of the neck, from which it passes obliquely downwards and backwards,
+covering the scapulo-humeral angle--that is, the region known as the
+point of the shoulder or arm--and is inserted into the anterior border
+of the humerus, the border which, limiting anteriorly the musculo-spiral
+groove, forms a continuation of the deltoid impression. On account of
+the regions with which it is related, Bourgelat named this muscle _the
+muscle common to the head, neck, and arm_.
+
+It is at the level of the scapulo-humeral angle that the vestiges of the
+clavicle are found.
+
+This bone is represented in some animals--the pig, ox, and horse--by a
+single tendinous intersection, more or less apparent, which extends
+transversely from the scapula to the anterior extremity of the sternum.
+In the dog and the cat, we find, besides, on the deep surface of the
+muscle and at the level of this tendinous intersection, the rudiment of
+the clavicle of which we made mention in the section on Osteology (see
+p. 25).
+
+It is beneath the intersection, the existence of which we have just
+pointed out, that is found that portion of the mastoido-humeral muscle
+which corresponds to the clavicular fasciculi of the deltoid; that
+portion which is situated above the intersection corresponds to the
+clavicular fibres of the sterno-cleido-mastoid and of the trapezius.
+
+The mastoido-humeral presents certain varieties in different animals.
+
+In the dog and the cat, this muscle, which is blended above with the
+sterno-mastoid (see p. 153), to be inserted with it into the mastoid
+process and the mastoid crest, covers the neck for a considerable extent
+from the superior curved line of the occipital bone to which it is
+attached, to the trapezius with which it unites posteriorly, but from
+which it separates below. Between these two extreme points of its
+superior portion it is attached to the cervical ligament.
+
+In the pig and in ruminants, in which the trapezius approaches more
+closely to the head, the mastoido-humeral occupies, in consequence, a
+less extent of the cervical region.
+
+In the horse, the mastoido-humeral neither covers the neck nor joins the
+trapezius; indeed, we have already shown that it is separated by a
+considerable distance from the head. In the limited interval between
+these two muscles a part of the rhomboid and parts of other muscles are
+seen with which we shall soon be occupied.
+
+This muscle, as regards the horse, is described by some anatomists as
+consisting of two parts: one anterior, or superficial; the other
+posterior, or deep. In reality, the first only corresponds to the
+mastoido-humeral, which we are considering; the posterior may be more
+exactly regarded as representing a special muscle of quadrupeds, but
+which is here a little deformed, the _omo-trachelian_ (see p. 155).
+
+When the mastoido-humeral contracts, taking its fixed point above, it
+acts as an extensor of the humerus, and carries the entire fore-limb
+forwards. If it takes its fixed point below--that is to say, at the
+humerus--it inclines the head and neck to its own side. If it contracts
+at the same time as the mastoido-humeral of the opposite side, then the
+head and the neck are carried into the position of extension.
+
+=The Sterno-mastoid= (Fig. 66, 5; Fig. 68, 11; Fig. 69, 15;
+Fig. 70, 17).--Having described the clavicular portion of the
+sterno-cleido-mastoid in connection with the mastoido-humeral, because
+it forms a part of the latter, we have, in order to complete the
+homologies of this muscle, to study now that which corresponds to its
+sternal portion. This is the _sterno-mastoid_ muscle. In all the
+quadrupeds with which we are here concerned this muscle arises from the
+anterior extremity of the sternum; narrow and elongated in form, it
+passes towards the head in a direction parallel to the anterior border
+of the mastoido-humeral, from which it is separated by an interspace
+which, along its whole length, lodges superficially the jugular vein;
+hence the name of _jugular groove_, which is given to this part of the
+neck (Fig. 10, 18).
+
+It is inserted, in the case of the dog and cat, into the mastoid
+process, where it is united with the mastoido-humeral; in the ox it is
+divided into two portions--one which goes to the base of the occipital
+bone, the other passing in front of the masseter is by the medium of
+the aponeurosis of this latter attached to the zygomatic crest. This
+latter part is considered by some writers as forming a portion of the
+panniculus muscle of the neck.
+
+In the horse it is attached to the angle of the lower jaw by a tendon,
+which an aponeurosis that passes under the parotid gland binds to the
+mastoido-humeral muscle and the mastoid process.
+
+By reason of this insertion into the jaw, in the case of the solipeds,
+this muscle is further named the _sterno-maxillary_.
+
+When it contracts, it flexes the head, and inclines it laterally. This
+movement is changed to direct flexion when the two sterno-mastoid
+muscles contract simultaneously.
+
+In man, the sterno-cleido-mastoid and the trapezius leave a triangular
+space between them, which, being limited inferiorly by the middle third
+of the clavicle, is known as the supraclavicular region; this region,
+being depressed, especially in its inferior part, has also been given
+the name of supraclavicular fossa--popularly called the '_salt-cellar_.'
+
+The muscles which form the floor of this region, passing from above
+downwards, are: a very small portion of the complexus, splenius, levator
+anguli scapulae, posterior scalenus, and anterior scalenus; then,
+crossing these latter, and most superficial, is the omo-hyoid muscle.
+
+An analogous region, but of only slight depth, exists in quadrupeds; its
+borders are formed by the mastoido-humeral and trapezius muscles.
+
+It is not limited below by the clavicle--we know, indeed, that this, or
+the intersection which represents it, belongs to the mastoido-humeral
+muscle--but by the inferior portion of the spine of the scapula.
+
+It is of greater or less extent according to the species considered.
+
+In the dog, cat, pig, and ox, it is narrow, for the muscles which bound
+it approach one another pretty closely. It has, as in man, the form of a
+triangle, with the apex above. In the horse it is much broader, and,
+contrary to the arrangement which it presents in the human species, the
+widest part is directed upwards.
+
+The muscles which we find there are, consequently, more or less
+numerous. In the dog and cat they are: a portion of a muscle which we do
+not normally meet with in man--the _omo-trachelian_--then in a
+decreasing extent: supraspinatus, levator anguli scapulae and splenius.
+
+In the pig: the omo-trachelian, supraspinatus, and the terminal portion
+of the sterno-prescapular--the anterior part of the lesser or deep
+pectoral muscle.
+
+In the ox: the omo-trachelian only.
+
+But in the horse we find the omo-trachelian, the supraspinatus, and the
+terminal extremity of the sterno-prescapular; then in a larger extent of
+area the levator anguli scapulae and the splenius; and, finally, the
+anterior portion of the rhomboid.
+
+Among the muscles which we have just enumerated are some that we have
+already studied; these are the sterno-prescapular and the rhomboid. We
+will examine the supraspinatus muscle in connection with the region of
+the shoulder.
+
+As to the scaleni muscles and the complexus, they are deeply situated,
+whereas the omo-hyoid is visible in the anterior region of the neck
+only.
+
+There remain for us, accordingly, to examine, at the present juncture,
+but the omo-trachelian, levator anguli scapulae, and splenius muscles.
+
+=The Omo-trachelian Muscle= (Fig. 68, 13; Fig. 69, 17; Fig. 70,
+20).--Also called the _acromio-trachelian_, _levator ventri
+scapulae_,[21] the _angulo-ventral muscle_, and the
+_transverso-scapular_,[22] etc., this muscle is described by some
+hippotomists as belonging to the mastoido-humeral, of which it then
+forms its posterior or deep portion (see p. 153).
+
+  [21] Ventri, because inserted into the inferior part of the spine of
+       the scapula, towards the acromion--that is, on the ventral
+       side--by contrast with the trapezius, which is attached higher up
+       (dorsal side) on the same process.
+
+  [22] Among the many names given to this muscle, Arloing and Lesbre
+       recommend the adoption of the name 'transverse scapular' given by
+       Straus-Durckheim, or 'transverse of the shoulder' (Arloing and
+       Lesbre, 'Suggestions for the Reform of Veterinarian Muscular
+       Nomenclature,' Lyons, 1898).
+
+The omo-trachelian muscle is found in all mammalia, man alone excepted.
+It is, however, sometimes found in the human being; but it then
+constitutes an anomaly.
+
+In the dog, pig, and ox, it arises from the inferior part of the spine
+of the scapula, in the region of the acromion, and terminates on the
+lateral portion of the atlas.
+
+In the cat it is attached besides to the base of the occipital bone. It
+is visible in the space limited by the trapezius and the
+mastoido-humeral, the direction of which it crosses obliquely.
+
+In the horse it appears to be blended in clearly defined fashion with
+the mastoido-humeral. Attached below, like this latter, to the anterior
+border of the humerus, it covers the scapulo-humeral angle; and is
+attached by its upper portion to the transverse processes of the first
+four cervical vertebrae.
+
+We remember that the transverse processes are often, from their relation
+with the trachea, known as the tracheal processes. Hence the word
+'trachelian,' which forms part of the name of the muscle with which we
+are now dealing.
+
+By its contraction it helps to draw the anterior limb forwards.
+
+When this muscle, as an abnormality, exists in man, it arises from
+the clavicle or the acromion process, traverses the supraclavicular
+fossa, and is inserted into the transverse processes of the atlas or
+axis, or of both these vertebrae, or of the cervical vertebrae below
+these latter. It is then known by the names of the _elevator of the
+clavicle_ or _elevator of the scapula_, and, finally, as the
+_cleido-omo-transversalis_ (Testut).[23]
+
+  [23] L. Testut, 'Les anomalies musculaires chez l'homme expliquees par
+       l'anatomie comparee,' Paris, 1884, p. 97. A. F. Le Double,
+       'Traite des variations du systeme musculaire de l'homme et de
+       leur signification au point de vue de l'anthropologie
+       zoologique,' Paris, 1897, t. i., p. 235.
+
+=The Levator Anguli Scapulae= (Fig. 68, 15; Fig. 70, 23).--As we have
+pointed out (p. 136), the levator anguli scapulae, because of its
+connections with the great serratus, is sometimes described with it. But
+inasmuch as in human anatomy these two muscles are considered
+separately, and that, in the superficial layer of muscles, they are seen
+in different regions--the great serratus in the thoracic, and the
+levator anguli scapulae in the cervical--we prefer to study them
+separately.
+
+We remember that in man this muscle arises from the transverse processes
+of the upper cervical vertebrae and is inserted into the superior portion
+of the spinal border of the scapula, into the portion of this border
+which is situated above the spine; it also contributes to the formation
+of the floor of the supraclavicular region.
+
+When it contracts, it draws the superior portion of the scapula forwards
+and upwards, and causes a see-saw movement, for at the same time the
+inferior angle of the scapula is directed backwards. Taking its fixed
+point at the shoulder, it directly extends the neck if the muscle of one
+side acts at the same time as that of the opposite; but if only one
+muscle contracts it inclines the neck to the corresponding side.
+
+It is to be noticed that during movements a little more active than the
+ordinary the levator anguli scapulae, as moreover the other muscles of
+the neck do, becomes very distinct. We have, indeed, often remarked
+that, apart from these movements, each time the support of one of the
+fore-limbs is brought into requisition a brusque contraction of the
+muscles of this region accompanies it.
+
+This contraction gives the impression that, as on the one hand, each
+support determines a momentary arrest of progression, a jolt, and on the
+other hand, the head continues to be projected in the forward direction,
+the latter should be retained. But it cannot be so except by an effort
+in the opposite direction--that is to say, by the brusque contraction
+which we have just pointed out.
+
+Analogous contractions also take place in a man while running at the
+beginning of each contact of the lower limbs with the ground.
+
+We may add, apropos of this latter, that displacements of the head,
+sometimes in very pronounced fashion, take place during simple walking,
+and that every time one of the lower limbs is carried forwards the head
+is projected in the same direction. These displacements, which we also
+find take place in the horse in pacing, especially in the region of the
+neck and head, seem then to have the effect of aiding the progression of
+the body forwards.
+
+They occur especially in animals when drawing a heavy load, and in
+individuals whose walking movements are executed with difficulty.
+
+It is necessary to repeat that, in these cases, the individual appears
+to assist the movement of his body by the impetus which the projection
+of his head forward determines, in order to add--and it is for this that
+we have referred to the subject--that during the intervals between each
+projection the head is carried backwards by a muscular contraction
+similar to that above discussed.
+
+=The Splenius= (Fig. 68, 14; Fig. 70, 22).--In man, this muscle is
+attached in the median line to the inferior half or two-thirds of the
+posterior cervical ligament, to the spinous processes of the seventh
+cervical, and four or five upper dorsal vertebrae; it passes obliquely
+upwards and outwards, becomes visible in the supraclavicular region,
+passes under the sterno-cleido-mastoid, and proceeds to duplicate the
+cranial insertions of this latter; and, further, the most external
+fasciculi of this muscle are inserted into the transverse processes of
+the atlas and the axis.
+
+These separate superior attachments, and the division of the muscle
+which results, have caused the splenius to be regarded as formed of two
+portions: splenius of the head, and splenius of the neck.
+
+In the horse, this muscle, which is of voluminous dimensions, arises
+from the superior cervical ligament, and the spinous processes of the
+first four or five dorsal vertebrae; thence it proceeds to be inserted
+into the mastoid crest, and the transverse processes of the atlas and
+three or four vertebrae following.
+
+The region occupied superficially by the splenius is remarkable for the
+prominence which this muscle, with the deeply-seated complexus, which is
+equally bulky, determines at this level; it is situated above that
+region of the neck, in which are seen in part the fasciculi of the
+levator anguli scapulae. It terminates above and in front in the ridge,
+which is sometimes very pronounced, which the transverse processes of
+the atlas make on each side of this part of the neck.
+
+In the dog and the cat, the superior and anterior region of the neck is
+thick and of rounded form, on account of the development which the
+splenius presents in those animals; but it is covered by the
+mastoido-humeral.
+
+This latter relation is also found in the ox, but the splenius in this
+case is but slightly developed.
+
+When the splenius contracts it extends the head and neck, while
+inclining them to its own side.
+
+If the splenius of one side contracts at the same time as that of the
+opposite, the extension takes place in a direct manner--that is to say,
+without any modifying lateral movement.
+
+
+Infrahyoid Muscles
+
+Having studied the lateral surfaces of the neck, we must now examine the
+anterior part of this region. Here, between the two sterno-mastoid
+muscles, we find a space broader above than below, in which are situated
+the larynx and the trachea, to the general arrangement of which is due
+the cylindrical form which this region presents. This space corresponds
+to that which in the neck of man is limited laterally by the
+sterno-cleido-mastoid muscles, below by the fourchette of the sternum,
+and above by the hyoid bone. In animals, as in man, it is called the
+infrahyoid region.
+
+The hyoid bone in quadrupeds is situated between the two rami or
+branches of the lower jaw. Owing to this disposition, the region above
+this bone, instead of having its surface projecting a little beyond the
+inferior border of the maxillary bone, is depressed. This is especially
+so in the horse. It is there that we find in this animal the region
+known as the _trough_ (_auge_); the larynx corresponds to that part
+known as the _gullet_.
+
+The muscles which occupy the infrahyoid region are: the sterno-thyroid,
+the sterno-hyoid, and the omo-hyoid. There is also a thyro-hyoid, but
+because of its deep situation and its slight importance it offers no
+interest from our point of view.
+
+=Sterno-thyroid and the Sterno-hyoid Muscles.=--These two muscles, long,
+narrow, and flat, arise from the anterior extremity of the sternum;
+then, covering the anterior surface of the trachea, they proceed to
+terminate, the one on the thyroid cartilage, and the other on the hyoid
+bone. The sterno-hyoid is superficial; it covers the sterno-thyroid,
+which, however, projects a little on its outer side.
+
+=Omo-hyoid.=--This muscle does not exist in the dog or cat. It arises,
+in the horse, from the cervical border of the scapula, where it blends
+with the aponeurosis that envelops the subscapularis muscle, but in the
+pig and the ox it arises from the deep surface of the mastoido-humeral
+muscle. It is directed obliquely upwards and inwards, becoming
+superficial at the internal border of the sterno-mastoid, and is
+inserted into the hyoid bone.
+
+The region in which are united the portion of the neck which we have
+just studied and the neighbouring part of the thorax--that is, the
+breast--has certainly, in our opinion, a form less expressive than the
+corresponding region in man.
+
+In the latter, indeed, the fourchette of the sternum, with the
+hollow which it determines, the heads of the clavicles, and the
+sterno-cleido-mastoid muscles, by the elevations which they produce, and
+the trachea, by the situation which it occupies in the inferior part,
+constitute a whole in which are admirably indicated, not only the forms
+of the organs which constitute this region, but also the relations which
+these organs have one with another; and, to a certain extent, their
+respective functions.
+
+In making an exception in the case of the ox, in which a fold of skin,
+the _dewlap_, which passes from the neck to the breast, constitutes an
+element of form which possesses some expressive value; in the horse and
+in the dog, which possess no sternal fourchette and no heads of
+clavicles, the bones and the muscles are found nearly on the same plane.
+This produces a uniformity which is evidently inferior, from an
+aesthetic point of view, to the modelling of the corresponding region of
+the human body. Such, at least, is our impression.
+
+
+Suprahyoid Muscles
+
+As their name indicates, these muscles are found above the hyoid bone;
+amongst those which should arrest our attention for a moment are the
+mylo-hyoid and the digastric.
+
+=Mylo-hyoid.=--This muscle, forming a sort of fleshy sling which
+contributes in great measure to form the floor of the mouth, is situated
+between the lateral halves of the inferior maxillary bone. Arising on
+each side from the internal oblique line of the mandible, its fibres are
+directed towards the median line, to be inserted posteriorly into the
+hyoid bone, and, between this bone and the anterior part of the
+mandible, into a median raphe which unites these latter.
+
+=Digastric.=--This muscle arises from the styloid process of the
+occipital bone and from the jugular process; it thence passes downwards
+and forwards, and terminates variously, in different species. In the ox
+and the horse it terminates in its anterior portion on the internal
+surface of the inferior maxillary bone, close to the chin. But in the
+horse a bundle of fibres is detached from the upper portion of the
+muscle, to be inserted into the recurved portion of the jaw. It is to
+this fasciculus that Bourgelat has given the name of '_stylo-maxillary
+muscle_.'
+
+In the pig, dog, and cat, the digastric differs more from the
+corresponding muscle in man; it is not, as in the latter, formed of two
+parts. The anterior portion only exists. This consists of a thick
+muscular mass, which is inserted into the middle of the internal surface
+of the lower jaw.
+
+In the dog and cat it is clearly recognisable in the superficial layer
+of muscles by the long and thick prominence which it produces below the
+masseter, against the inferior border of the mandible (see pp. 235 and
+237, the two figures showing the myology of the head of the dog).
+
+By its contraction, it draws the lower jaw downwards and backwards.
+
+=Panniculus of the Neck.=--This very thin muscle, which cannot be
+recognised on the exterior, calls for little notice.
+
+We shall merely point out that it duplicates the skin of the cervical
+region; but as the latter is only slightly adherent to it, the
+panniculus of this region seems rather destined to maintain in position
+the muscles which it covers than to displace the cutaneous covering.
+
+We recall the fact that in man, on the contrary, the muscle is very
+evident at the instant of its contraction, and, for this reason, it
+presents a very great interest with regard to external modelling, and it
+plays an important part in the expression of the physiognomy.
+
+
+MUSCLES OF THE ANTERIOR LIMBS
+
+
+Muscles of the Shoulder
+
+=Deltoid= (Fig. 68, 16, 17; Fig. 69, 18; Fig. 70, 24).--This is the
+first muscle we study in connection with the shoulder in human anatomy.
+Indeed, its wholly superficial position, and especially the manner in
+which it is separated from the surrounding muscles, its volume, and its
+characteristic modelling, give it such an importance that, from the
+didactic point of view, there is every indication for commencing with
+this muscle in studying the region to which it belongs. If, in regard to
+quadrupeds, we also commence with it, it is merely in deference to the
+spirit of method, and for the sake of symmetry; for it is far from
+presenting, in the latter, characters so distinctive and so clearly
+defined.
+
+It is necessary to remark, at the outset, that in quadrupeds, on account
+of the absence or slight development of the clavicle, the clavicular
+portion of this muscle is, as we have shown, united to bundles of the
+same kind belonging to the sterno-cleido-mastoid and trapezius to form
+the mastoido-humeral (see p. 151). There exists, therefore, in an
+independent form, the scapular portion only.
+
+It is this latter which, by itself alone, forms the deltoid of
+quadrupeds, a muscle known, in veterinary anatomy, as _the long abductor
+of the arm_.
+
+In the dog and the cat it consists of two parts, one of which arises
+from the spine of the scapula; the other from the acromion process.
+Thence it passes to the crest of the humerus, which limits the
+musculo-spiral groove anteriorly, to be attached at a point which is
+found, as in other quadrupeds, to be the homologue of the human deltoid
+impression, or deltoid [V], of the human humerus.
+
+In the ox, in which the acromion process, which is very rudimentary,
+does not attain the level of the glenoid cavity, the acromion portion is
+but slightly marked off from that which takes its origin from the spine
+of the scapula.
+
+Still, in the horse, which is completely deprived of an acromion
+process, the deltoid muscle is correspondingly divided into two parts,
+separated from one another by superficial interstices, but of which the
+arrangement differs from that of the portions above indicated; one part,
+the posterior, arises above from the superior part of the posterior
+border, and the postero-superior angle of the scapula (exactly as if, in
+man, certain fasciculi of the deltoid took their origin from the
+axillary border and inferior angle of the scapula); the other, anterior,
+arises from the tuberosity of the spine of the same bone. The two parts,
+united inferiorly, proceed to be inserted into the deltoid impression or
+infratrochiterian crest of the humerus.
+
+It is necessary to add that the deltoid is inserted into the humerus,
+above the insertion of the mastoido-humeral.
+
+This muscle flexes and abducts the humerus, and also rotates it
+outwards.
+
+With regard to the other muscles of the human shoulder, subscapularis,
+supraspinatus, infraspinatus, teres minor and teres major, they are also
+present in quadrupeds, but in a form more elongated, as the scapula has
+its dimensions more extended from below upwards--that is, from the
+glenoid cavity towards the superior or spinal border.
+
+=Subscapularis.=--This muscle occupies the subscapular fossa, from which
+it takes its origin, leaving free the superior part where the surface is
+found, to which are attached the serratus magnus and the levator anguli
+scapulae. It passes towards the arm, to be inserted into the small
+tuberosity of the humerus. It is an adductor of the arm.
+
+The subscapularis does not offer any interest from the point of view of
+external form, for it is completely covered by the scapula.
+
+We speak of it, however, because we mention it in human anatomy, and
+that it affords us here a new opportunity of bringing into prominence
+the differences which exist in connection with the mobility of the
+shoulder.
+
+We remember that in man, when the arm is abducted, and then raised a
+little above the horizontal, the scapula see-saws, is separated, to a
+certain extent, from the thoracic cage inferiorly and externally, and
+that, on the superficial layer of muscles, we are then able to see in
+the bottom of the armpit, at the level of the deep portion of the
+posterior wall of the latter, a small part of the subscapularis muscle.
+
+In the animals with which we are here occupied it is not the same; for
+they are incapable of performing with their fore-limbs a movement
+analogous to that to which we have just referred, the humerus in their
+case being retained in contact with the trunk by the muscular masses
+which surround it.
+
+=Supraspinatus= (Fig. 68, 19; Fig. 70, 25; Fig. 72, 7).--This muscle, as
+its name indicates, occupies the supraspinous fossa--that is to say,
+that which, by reason of the direction of the scapula in quadrupeds, is
+situated in front of rather than above the spine. It arises from this
+fossa; and, further, from the external surface of the cartilage which
+prolongs the scapula upwards in solipeds and ruminants. It projects more
+or less beyond the supraspinous fossa in front.
+
+After passing downwards towards the humerus, it is inserted into the
+summit of the great tuberosity or trochiter--that is to say, to a part
+of this osseous prominence which represents the anterior facet of the
+great tuberosity of the human humerus, into which, as we know, the
+corresponding muscle is inserted.
+
+In solipeds and ruminants it is inserted, by a second fasciculus, into
+the small tuberosity.
+
+In the pig and the horse its anterior border is in relation with the
+terminal portion of the sterno-prescapular anterior portion of the small
+or deep pectoral.
+
+The supraspinatus, which in man is completely covered by the trapezius,
+is partly visible in the superficial layer of the cat, dog, pig, and
+horse, in the lower part of the space limited by the mastoido-humeral
+and the trapezius. It is crossed by the scapulo-trachelian.
+
+It is, in the ox, completely covered by these muscles, but its form,
+notwithstanding this, is easily discerned by the prominence which it
+produces. When it contracts, the supraspinatus muscle carries the
+humerus into the position of extension.
+
+=Infraspinatus= (Fig. 68, 20; Fig. 72, 8).--This muscle, which occupies
+the infraspinous fossa, which, in quadrupeds, is situated behind the
+spine of the scapula, arises from the whole extent of this fossa, and in
+solipeds and ruminants encroaches on the cartilage of prolongation. Its
+fibres are directed downwards and forwards, to be inserted into the
+great tuberosity of the humerus--the trochiter--below the insertion of
+the supraspinatus.
+
+It is completely covered (ox and horse), or in part only (cat and dog),
+by the portion of the deltoid which arises from the spine of the
+scapula; nevertheless, its presence is revealed by the prominence which
+it produces.
+
+It is an abductor and external rotator of the humerus.
+
+In connection with this muscle, which, as we have just pointed out, is
+less seen in the superficial muscular layer than the supraspinatus, we
+will draw attention to the fact that this arrangement is exactly the
+reverse of that which is found in the human shoulder. In this latter it
+is the supraspinatus which is not visible; while, on the contrary, the
+infraspinatus is uncovered in a considerable part of its extent. We
+further notice that it is accompanied by the teres minor, and that the
+teres major, situated inferiorly, forms with these two muscles a fleshy
+mass which, below, ends on the superior border of the great dorsal
+muscle.
+
+In quadrupeds, in which the infraspinatus is so slightly visible, the
+teres major and minor are not found at all in the superficial muscular
+layer.
+
+Accordingly, we will say but few words about them.
+
+[Illustration: FIG. 72.--MYOLOGY OF THE HORSE--SHOULDER AND ARM: LEFT
+SIDE, EXTERNAL SURFACE.
+
+1, Cartilage of prolongation of the scapula; 2, tuberosity of the spine
+of the scapula; 3, superior extremity of the humerus; 4, inferior
+extremity of the humerus; 5, radius; 6, ulna; 7, supraspinatus muscle;
+8, infraspinatus; 9, teres minor; 10, biceps; 11, tendon of the biceps
+passing over the anterior surface of the superior extremity of the
+humerus; 12, brachialis anticus; 13, triceps, long head; 14, external
+head of the triceps divided; 15, external head of the triceps reflected,
+in order to expose the anconeus; 16, region normally occupied by the
+external head of the triceps; 17, anconeus.]
+
+=Teres Minor= (Fig. 72, 9).--This muscle, also called in veterinary
+anatomy _the short abductor of the arm_, arises from the posterior
+border of the scapula (the external border in man), and is inserted
+below the great tuberosity of the humerus, between the attachments of
+the infraspinatus and deltoid.
+
+It is covered by the deltoid and the infraspinatus.
+
+=Teres Major.=--This muscle is known to veterinarians as _the abductor
+of the arm_; it arises from the postero-superior angle of the scapula
+(the inferior angle of the human scapula), from which it passes to be
+inserted into the internal surface of the humerus.
+
+It is covered by the latissimus dorsi and the posterior muscular mass of
+the arm.
+
+In brief, for the better understanding of the relations of the teres
+major and minor muscles in quadrupeds, we may fancy the corresponding
+muscles in man modified in the following manner: The infraspinatus,
+thicker, covering the teres minor; latissimus dorsi, more extended in
+its superior part, covering a large proportion of the teres major. As to
+the relations of the teres minor with the deltoid, they exist in man,
+seeing, in this case, the same muscle is, in its external portion,
+covered by this latter. With regard to the relations of the teres major
+with the posterior muscular mass of the arm, they also exist in man,
+since the external surface of this muscle is covered by the triceps.
+
+These modifications are sufficient to render the small and large teres
+muscles completely invisible in the superficial layer.
+
+The muscles of the shoulder which we have just been studying fulfil,
+with regard to the articulation which they surround, the function of
+active ligaments. This role is made necessary by the laxity of the
+scapulo-humeral capsule--a laxity which renders it incapable by itself
+of maintaining the bones in contact at this joint.
+
+The same condition exists in man.
+
+=Panniculus Muscle of the Shoulder.=--This thin muscle covers, as its
+name implies, the region of the shoulder, and is the continuation
+forward of the panniculus muscle of the trunk.
+
+It arises, by its superior part, from the region of the withers and from
+the superior cervical ligament; thence its fibres descend directly
+towards the elbow, to terminate at the level of the region of the
+forearm.
+
+The muscle is not found in the pig or in the carnivora.
+
+
+Muscles of the Arm
+
+We should remember, at the outset, that in man the muscles of the arm
+are divided into two groups: one anterior, which contains the biceps,
+brachialis anticus, and the coraco-brachialis; the other, posterior,
+which is constituted by a single muscle, the triceps.
+
+In animals, we find them in the same number and arranged in analogous
+fashion--that is to say, in two groups--with respect to the bone of the
+arm. But then we find that they have undergone a transformation with
+regard to their length, and it is the change of general aspect which
+results from this modification that we proceed to examine.
+
+We know that in quadrupeds, and especially in the domestic animals, the
+humerus is relatively short in proportion to the forearm. We have
+already seen, in dealing with the bones, that whilst in the human
+species the humerus is longer than the forearm, in the dog and cat these
+two segments of the fore-limb are of equal length, and that the humerus
+of the horse is, on the contrary, much shorter. Now, let us suppose the
+human humerus to be shorter than it is in reality; the anterior muscles
+undergoing, very naturally, the same reduction, will be uncovered only
+slightly by those above--the deltoid and the great pectoral--or will
+remain completely hidden by them. Thus would be found realized the
+disposition which we meet with in quadrupeds of the muscles of this
+region.
+
+With regard to the posterior muscular mass of the arm, it does not
+undergo the same change. The muscle which constitutes it--the triceps
+cubiti--occupies, on the contrary, a greater area. Let us suppose,
+further--for it is the best method of comprehending the homologies which
+now occupy our attention--the humerus of man to be shortened as before,
+and directed downwards and backwards (as in quadrupeds), this bone would
+form an acute angle with the axillary border of the scapula. Let us
+suppose also that the long portion of the triceps, instead of arising
+solely from the superior part of this axillary border, is attached to
+the whole length of the latter, and that the triceps fills the whole
+interior of the angle formed by the arm and the shoulder. We then shall
+have an idea of what the triceps is in quadrupeds. It is necessary to
+add that the general resemblance would be still more complete if the arm
+were firmly supported by the side of the thorax, because in quadrupeds
+it occupies an analogous position, determined by the arrangement of the
+muscles which, proceeding from the trunk and neck, are attached to it.
+
+
+Anterior Region
+
+=Biceps Cubiti= (Fig. 68, 21; Fig. 72, 10, 11).--This muscle, also
+called _the long flexor of the forearm_, does not merit the name except
+by its analogy with the corresponding muscle in man. Indeed, in the
+domestic animals it is not divided into two parts; it is represented by
+a single fasciculus, long and fusiform, situated on the front of the
+humerus, and directed obliquely downwards and backwards, as the latter,
+on its part, is also inclined.
+
+It arises above from a tubercle at the base of the coracoid process,
+which surmounts the glenoid cavity of the scapula. Its tendon, which is
+highly developed in the solipeds, occupies the bicipital groove. We
+remember that in these latter the groove in question is divided into two
+channels by a median prominence.
+
+The tendon in which the muscle ends is inserted into a tuberosity,
+situated on the internal surface of the superior extremity of the
+radius--the bicipital tuberosity. In the pig, the cat, and the dog,
+there is detached from the tendon to which we have just referred a
+fasciculus of the same nature, which, after having wound round the
+radius, is inserted into the internal surface of the ulna, towards the
+base of the olecranon process. From the inferior part of the muscle
+arises a fibrous band, comparable to the aponeurotic expansion of the
+human biceps; but, instead of passing downwards and inwards, as does the
+latter, it terminates on the muscular mass which constitutes the
+antero-external part of the forearm.
+
+The biceps is not seen in the superficial layer, except in the dog and
+cat (in which the humerus is, in fact, proportionately long); and even
+in them only to the slightest extent. It is covered partly in these
+latter, and completely in other animals, by the great pectoral and the
+inferior portion of the mastoido-humeral--that is to say, that part of
+the latter which represents the whole of the clavicular fibres of the
+human deltoid.
+
+The biceps is a flexor of the forearm on the arm. It also contributes to
+the movement of extension of the humerus.
+
+=Brachialis Anticus= (Fig. 68, 22; Fig. 69, 19; Fig. 70, 27; Fig. 72,
+12).--In veterinary anatomy further designated as _the short flexor of
+the forearm_, this muscle, which is thick, occupies the musculo-spiral
+groove, and arises from it, reaching upwards to just below the head of
+the humerus. But it does not, as in man, extend to the internal surface
+of the bone.
+
+Situated on the outside of the biceps, it is directed towards the
+forearm, and terminates by a flattened tendon, which, dividing into two
+slips, passes below the bicipital tuberosity, on the internal surface of
+the radius, into which one of these slips is inserted, while the other
+proceeds to terminate on the ulna.
+
+The inferior half of this muscle is visible on the superficial layer, in
+the space limited posteriorly by the triceps brachialis, and below by
+the muscles of the forearm, which correspond to the external muscles of
+the human forearm, and in front by the great pectoral and the
+mastoido-humeral. It is in the upper part of the interspace which
+separates these latter from the brachialis anticus that the deltoid
+insinuates itself to proceed to its insertion into the humerus.
+
+These relations precisely recall those which we meet with when we
+examine the external surface of the human arm, with this difference,
+however--that in the latter the anterior brachialis anticus is
+extensively related, in front, to the biceps. However, in animals it is
+not absolutely the same, since, as we have shown above, the biceps is
+covered, more or less completely, by the mastoido-humeral and the great
+pectoral.
+
+The brachialis anticus flexes the forearm on the arm.
+
+=Coraco-brachialis.=--In man this muscle, which occupies the superior
+half, or third, of the internal surface of the humerus, is visible only
+when the arm is abducted, and then especially when it approaches the
+vertical position; indeed, it is only in this attitude that the region
+which it occupies is accessible to view.
+
+But an analogous attitude not being possible in domestic animals, in
+which the arm is fixed along the corresponding parts of the trunk, the
+result is that the coraco-brachialis is always covered, and that,
+consequently, it presents nothing of interest from our point of view. We
+speak of it, then, merely in order to complete the series of the muscles
+of the anterior surface of the arm, among which we rank it, in spite of
+the fact that in veterinary anatomy it is described as a muscle of the
+shoulder.
+
+It arises above from the coracoid process, and thence passes downwards
+towards the internal surface of the humerus into which it is inserted,
+more or less high up, according to the species. The coraco-brachialis is
+an adductor of the arm.
+
+
+Posterior Region
+
+=Triceps Cubiti= (Fig. 68, 23, 24; Fig. 69, 20, 21; Fig. 70, 28, 29;
+Fig. 72, 13, 14, 15, 16).--This muscle, which is voluminous in the
+quadrupeds with which we are here concerned, fits more or less
+completely the angular space between the scapula and the humerus. Its
+bulk forms a thick prominence, which surmounts the elbow and the
+forearm.
+
+We should say, with regard to this mass, that if the deltoid does not
+constitute in quadrupeds a prominence sufficient to remind one of that
+which this muscle produces in man, the triceps, in producing an
+analogous elevation, seems to replace in the general form of the body
+the relief which the deltoid is incapable of producing.
+
+The triceps is divided into three portions, which, as in man, have the
+names middle, or long head; external and internal heads. But that which
+renders the nomenclature a little complicated is that veterinary
+anatomists have given other names to these three parts: that of _great
+extensor of the forearm_ (caput magnum) to the long head; _the short
+extensor of the forearm_ (caput parvum) to the external head; and of
+_medium extensor of the forearm_ (caput medium) to the internal.[24]
+
+  [24] Other names given by certain authors to the parts of this muscle
+       which we have just enumerated still further complicate this
+       nomenclature.
+
+The long head is further designated by them under the names of the
+_long_ or _great anconeus_; the _external head_ under those of _external
+anconeus_, or _lateral_ or _short anconeus_; whilst the internal head
+becomes the _internal anconeus_, or _median_.
+
+It is more especially the long portion and the external head which,
+being visible on the external surface of the arm, contribute to the
+external form.
+
+The long portion, which is triangular in shape and of considerable
+development, arises in the cat and the dog from the inferior half or
+two-thirds of the posterior border of the scapula (axillary border);
+from the whole extent of that border as far as the superior posterior
+angle in the pig, the ox, and the horse; it then passes downwards
+towards the articulation of the elbow, to terminate in a tendon which is
+inserted into the olecranon process. The portion of this muscle which is
+next the scapula is covered by the deltoid.
+
+The external head, situated below the long portion, is directed
+obliquely downwards and backwards. It arises from the curved crest
+which, from the deltoid impression of the humerus, is directed upward to
+meet the articular head of the same bone. This crest limiting the
+musculo-spiral groove superiorly, and the brachialis anticus arising
+from the whole extent of this groove, the result is that at this level
+the external head is in relation with the brachialis anticus. From this
+origin it is directed towards the elbow, to be inserted into the
+olecranon, either directly or by the medium of the tendon of the long
+portion. The part of this muscle which arises from the humerus is
+covered by the deltoid.
+
+As for the internal head (Fig. 76, 4), which, in the superficial layer,
+is only visible in its inferior part, on the internal aspect of the arm
+in those animals in which the elbow is free of the lateral wall of the
+thorax (the dog and the cat, for example), it arises from the internal
+surface of the humerus, and thence proceeds to be inserted into the
+olecranon.
+
+The triceps extends the forearm on the arm.
+
+A fourth muscle exists, which veterinary anatomists include in the study
+of the three portions of the triceps which we have just been discussing,
+in giving it the name of _small extensor of the forearm_. But, as this
+muscle is no other than the anconeus, and as, in human anatomy, we
+describe the latter, according to custom, in connection with the
+forearm, it is when on the subject of the latter that we will concern
+ourselves with it. This grouping of muscles cannot fail to give greater
+clearness to the description of the muscles of these regions.
+
+=The Supplemental or Accessory Muscle of the Latissimus Dorsi= (Fig. 76,
+2; Fig. 77, 1).--Because of the relations, to which we have already
+referred (see p. 142), of this muscle with the triceps cubiti, its
+description very naturally follows that of the latter.
+
+Indeed, this supplementary muscle of the great dorsal is further
+designated in zoological anatomy under the name of _long extensor of the
+forearm_; and this name indicates that its study may be united to that
+of the triceps.
+
+Situated on the internal surface of the arm, it arises from the external
+aspect of the tendon of the latissimus dorsi; it is very highly
+developed in the horse, in which it also arises from the posterior
+border (axillary) of the scapula; then, covering in part the internal
+head of the triceps and also the long portion, on the superior border of
+which it is folded, it proceeds to be inserted into the olecranon
+process and the anti-brachial aponeurosis.
+
+It extends the forearm on the arm. Further, it makes tense the
+aponeurosis into which it is inserted; this explains the name of _tensor
+of the fascia of the forearm_, which is sometimes given to it.
+
+It seems to us interesting to add that, abnormally, we sometimes find in
+man an analogue of this muscle. It is given off from the latissimus
+dorsi, near the insertion of the latter into the humerus; it accompanies
+the long head of the triceps and becomes fused with it. Sometimes it is
+inserted into the olecranon process, at other times into the
+antibrachial aponeurosis or the epitrochlea. It is on account of its
+insertion into the last-mentioned, in some cases, that it is also
+designated by the name of _dorso-epitrochlear_ muscle.[25]
+
+  [25] L. Testut, 'Anomalies musculaires chez l'homme expliquees par
+       l'anatomie comparee,' Paris, 1884, p. 118. A. F. Le Double,
+       'Traite des variations du systeme musculaire de l'homme et de
+       leur signification au point de vue de l'anthropologie
+       zoologique,' Paris, 1897, t. i., p. 203. Edouard Cuyer,
+       'Anomalies musculaires' (_Bulletins de la Societe
+       Anthropologique_, Paris, 1893).
+
+
+Muscles of the Forearm
+
+Before commencing the special examination of each of the muscles of this
+region, it is absolutely indispensable to consider their general
+arrangement, and to determine very clearly how we should study them. We
+are too well convinced of the importance of this preliminary examination
+to dismiss it without entering rather fully into it. Indeed, the region
+on the myological study of which we are now entering is, unquestionably,
+one of the most complicated with which we have to deal. We know besides,
+in regard to the study of the forearm in man, how much a definite method
+is necessary in order that the arrangement of the muscles of this region
+be fixed in the memory, and that we are unable to obtain this result
+otherwise than by grouping the twenty muscles which constitute it in
+clearly defined regions.
+
+We also know that these muscles are first studied with the forearm in
+the position of supination, and that it is only when they are well known
+after having considered them in this position that we are able to
+analyze and comprehend their forms when it is in pronation.
+
+Now, as we have pointed out in the section on osteology (see p. 34), the
+forearm in quadrupeds is always in the position of pronation. Should we,
+then, in order to maintain the symmetry with human anatomy, first study
+the forearm in the position of supination? Evidently not. Besides the
+fact that this would in some cases be impossible since--as in the horse,
+for example--the radius and ulna are fused together, we should not gain
+any advantage; this position being never completely realizable even in
+those quadrupeds which have the radius relatively movable--as, for
+example, in the cat.
+
+Accordingly, it is pronation which here, in connection with animals,
+becomes the standard attitude from the point of view of description.
+This is why, supposing that the reader knows well the muscles of the
+human forearm in the position of supination, we should recall what is
+the general arrangement occupied by these muscles when it is in
+pronation.
+
+The fore-limb, being viewed on its anterior surface, presents above the
+anterior aspect of the region of the elbow; but below, it is the
+posterior surface of the wrist which is seen. Consequently, in the
+superior part, we see the external and anterior muscles limiting the
+hollow in front of the elbow; interiorly are found the posterior
+muscles.
+
+The long supinator, passing obliquely downwards and inwards, divides, in
+fact, the forearm into two parts: one supero-internal, the other
+infero-external. In the first we see, but to an extent less and less
+considerable, the pronator teres, the flexor carpi radialis, the
+palmaris longus, and the flexor ulnaris; as to the flexors of the
+digits, on account of the rotation of the radius, they are only visible
+on the opposite surface--that is to say, on the surface of the wrist,
+which is now posterior. In the second part we see the two radial
+extensors, the common extensor of the fingers, the proper extensor of
+the little finger, and the ulnar extensor which, inferiorly, remains
+behind, by reason of the position of the ulna being unchanged, whilst
+the anconeus is wholly posterior, since the direction of the elbow is
+not modified. We also find, in this region, the long abductor of the
+thumb, the short extensor of the thumb, the long extensor of the thumb,
+and the special extensor of the index-finger, in the region where these
+deep muscles become superficial.
+
+So that, to summarize, the external and posterior muscles occupy the
+anterior and external regions of the forearm, whilst the anterior
+muscles occupy rather the internal and posterior. It is in regarding
+them after this manner--that is to say, arranged in these two
+regions--that we proceed to study these muscles in quadrupeds.
+
+
+Anterior and External Region
+
+=Supinator Longus.=--We know that this muscle, which is especially a
+flexor of the forearm on the arm, plays, notwithstanding the name which
+has been given it, a part of but little importance in the movement of
+supination.
+
+It acts slightly, however, as a supinator, for, being very oblique
+downwards and inwards at the time of pronation, it is able, while
+tending to resume its vertical direction, to carry the radius outwards;
+it places, in fact, the forearm in a position midway between pronation
+and supination.
+
+We have just recalled these details, in order that it may be more easy
+to understand why it does not exist in animals in which the radius and
+ulna are fused together (horse, ox); and why, on the other hand, we find
+traces of it in the cat and the dog, in which the radius--to a slight
+extent, it is true--is able to rotate on the ulna. This displacement
+being a little more considerable in the felide, the long supinator is a
+little further developed than it is in the canine species; but,
+notwithstanding, it is only rudimentary.
+
+The long supinator arises, above, from the external border of the
+humerus; thence, in the form of a very narrow fleshy band, it passes
+obliquely downwards and inwards, to be inserted into the inferior part
+of the internal surface of the radius.
+
+It assists in turning the radius outwards and placing it in front of the
+ulna, the movement of supination being capable of being but little
+further extended.
+
+=First and Second External Radial Muscles=: _Extensor carpi radialis
+longior and brevior_ (Fig. 73, 8; Fig. 74, 8, 9; Fig. 75, 8, 9).--Fused
+together, these muscles form by their union what veterinary anatomists
+call _the anterior extensor of the metacarpus_. But we should add that
+these two muscles are united so much the more intimately as we examine
+them in passing successively from the cat to the dog, pig, ox, and
+horse. Thus, in the cat they are often distinct; in the dog, they unite
+only at the level of the middle third of the radius, and interiorly they
+have two tendons; in the pig, the ox, and the horse they are completely
+united, and there exists but a single tendon.
+
+The _anterior extensor of the metacarpus_, which is situated behind the
+long supinator when the latter exists, occupies the external aspect of
+the forearm; its well-defined form absolutely recalls the prominence on
+the superior part of the external margin of the human forearm.
+
+It arises superiorly from the portion of the external border of the
+humerus which is situated above the epicondyle and behind the
+musculo-spiral groove. Its fleshy mass appears in the angular space
+bounded by the brachialis anticus and the triceps. The superior portion
+is covered by the external head of the triceps; yet, in the dog, the
+superior portion of its humeral attachment is the only part so covered.
+This muscle is directed forward and downwards; it is also inclined a
+little inwards in such manner as to proceed to occupy the anterior
+aspect of the forearm.
+
+Its fleshy belly is narrowed below, and, towards the inferior part of
+the forearm, is continued by a tendinous portion which is situated on
+the anterior surface of the carpus, after having traversed the median
+groove of the inferior extremity of the radius.
+
+In the cat and the dog, in which the union of the two radial extensors
+is incomplete, the two tendons are inserted into the front of the base
+of the second and third metacarpal bones; consequently, as in man, into
+the metacarpals of the index and middle fingers.
+
+In the ox, the tendon, which is single, is inserted into the internal
+and anterior half of the superior extremity of the principal metacarpal.
+
+In the pig, this tendon is attached to the base of the large internal
+metacarpal.
+
+In the horse, the corresponding tendon is attached to a tubercle which
+is situated on the anterior surface of the base of the principal
+metacarpal, a little internal to the median plane of the latter.
+
+[Illustration: FIG. 73.--MYOLOGY OF THE DOG: LEFT ANTERIOR LIMB,
+EXTERNAL ASPECT.
+
+1, Mastoido-humeralis; 2, biceps; 3, brachialis anticus; 4, triceps,
+long portion; 5, triceps, external head; 6, olecranon process; 7,
+epicondyle; 8, radialis muscles (anterior extensor of the metacarpus);
+9, extensor communis digitorum (anterior extensor of the phalanges); 10,
+extensor minimi digiti (lateral extensor of the phalanges, or common
+extensor of the three external digits); 11, posterior ulnar (external
+flexor of the metacarpus); 12, pisiform bone; 13, anconeus; 14, extensor
+ossis metacarpi pollicis and extensor primi internodii pollicis (oblique
+extensor of the metacarpus); 15, radius; 16, anterior ulnar (oblique
+flexor of the metacarpus); 17, external border of the hypothenar
+eminence (abductor of the little finger).]
+
+In order to properly understand and remember the respective positions
+occupied by these inferior insertions, it must be remembered that the
+human forearm being in the position of pronation, the tendons of the
+radials are attached to the bases of the metacarpals nearest to the
+thumb--that is to say, those occupying an internal position as regards
+the fourth and fifth metacarpals.
+
+As its name indicates, this muscle extends the metacarpus. Consequently
+it is, in the horse, an extensor of the canon-bone.
+
+It is also an adductor of the hand in those animals (cat, dog) in which
+the radio-carpal articulation, analogous in form to the corresponding
+articulation in man, permits lateral movements of the hand on the
+forearm. The union of the fleshy bodies of the two radials is sometimes
+found in the human species.
+
+=Supinator Brevis.=--As in the case of the long supinator, the short
+supinator is found only in animals in which the radius can be rotated to
+a greater or less extent around the ulna; therefore this muscle is not
+found in the pig, the ox, or the horse; but it forms part of the forearm
+of the cat and the dog.
+
+Deeply situated at the region of the elbow, the short supinator has
+little interest for us. All that we will say of it is that it goes from
+the external part of the inferior extremity of the humerus to the
+superior part of the radius; and that it is, in carnivora, the essential
+agent in the production of the movement of supination.
+
+=Extensor Communis Digitorum= (Fig. 73, 9, 10, 11; Fig. 74, 10, 11,
+12).--Also named in veterinary anatomy the _anterior extensor of the
+phalanges_, this muscle is situated external to and behind the anterior
+extensor of the metacarpus already described.
+
+In the human being, the common extensor of the fingers springs, in its
+superior part, from the bottom of a depression, situated on the outer
+side of and behind the elbow, and limited in front by the muscular
+prominence which the long supinator and the first radial extensor form
+at that level. At the bottom of this hollow or fossette is found the
+epicondyle, which gives origin, amongst other muscles, to the common
+extensor of the fingers. It is necessary to add that it is most
+prominently visible during supination, and that it tends to be effaced
+during pronation.
+
+[Illustration: FIG. 74.--MYOLOGY OF THE OX: LEFT ANTERIOR LIMB, EXTERNAL
+ASPECT.
+
+1, Mastoido-humeralis; 2, pectoralis major; 3, deltoid; 4, brachialis
+anticus; 5, triceps; 6, triceps, external head; 7, olecranon; 8, radial
+extensors (anterior extensor of the metacarpus); 9, insertion of the
+tendon of the anterior extensor of the metacarpus to the tubercle of the
+superior extremity of the principal metacarpal; 10, 11, extensor
+communis digitorum (10, proper extensor of the inner digits; 11, common
+extensor of the two digits); 12, tendon of the common extensor of the
+two digits; 13, band of reinforcement from the suspensory ligament of
+the fetlock; 14, external tuberosity of the superior extremity of the
+radius; 15, extensor minimi digiti (proper extensor of the external
+digit); 16, tendon of the proper extensor of the external digit; 17,
+posterior ulnar (external flexor of the metacarpus); 18, pisiform; 19,
+extensor ossis metacarpi pollicis and extensor primi internodii pollicis
+(oblique extensor of the metacarpus); 20, ulnar portion of the deep
+flexor of the toes; 21, tendon of the superficial flexor of the toes
+(superficial flexor of the phalanges); 22, tendon of the deep flexor of
+the toes (deep flexor of the phalanges); 23, suspensory ligament of the
+fetlock.]
+
+An analogous arrangement is met with in animals. But the muscular
+prominence is formed by the united radial extensors, and the fossette,
+because of the permanent pronation of the forearm, is scarcely
+recognisable. Likewise, with regard to the dog, we may say that it does
+not exist, on account of the prominence which the epicondyle forms in
+that animal (Fig. 73, 7).
+
+In connection with this prominence of the epicondyle, it is interesting
+to add that this detail recalls the relief which the same process
+produces on the external aspect of the human elbow when the forearm is
+flexed on the arm. We know that, in this case, the epicondyle is
+exposed, because the muscles which mask it in supination (long supinator
+and long radial extensor) are displaced and set it free during flexion.
+But, in the dog, as in other quadrupeds besides, the forearm is, in the
+normal state, flexed on the arm; the latter being oblique downwards and
+backwards, and the former being vertical. Further, the epicondyle is
+well developed.
+
+The muscle with which we are now occupied, long and vertical in
+direction, arises from the inferior part of the external border of the
+humerus (there it is covered by the anterior extensor of the metacarpus,
+from which it is freed a little lower down) and from the external and
+superior tuberosity of the radius. In the carnivora, it arises from the
+epicondyle. Its fleshy body is fusiform in shape, becomes tendinous in
+the lower half of the forearm, and then divides into a number of slips,
+varying in number according to the species; this division is correlated
+to that of the hand--that is to say, with the number of the digits.
+Before reaching this latter, the common extensor of the digits passes
+through the most external groove on the anterior surface of the inferior
+extremity of the radius.
+
+[Illustration: FIG. 75.--MYOLOGY OF THE HORSE: LEFT ANTERIOR LIMB,
+EXTERNAL ASPECT.
+
+1, Mastoido-humeral; 2, pectoralis major; 3, deltoid; 4, brachialis
+anticus; 5, triceps, long head; 6, triceps, external head; 7, olecranon;
+8, radial extensors (anterior extensor of the metacarpus); 9, insertion
+of the tendon of the anterior extensor of the metacarpus into the
+tubercle of the superior extremity of the principal metacarpal; 10,
+extensor communis digitorum (anterior extensor of the phalanges); 11,
+tendon of the anterior extensor of the phalanges; 12, reinforcing band
+arising from the suspensory ligament of the fetlock; 13, external
+tuberosity of the superior extremity of the radius; 14, extensor minimi
+digiti (lateral extensor of the phalanges); 15, tendon of the lateral
+extensor of the phalanges; 16, fibrous band which this latter receives
+from the tendon of the anterior extensor of the phalanges; 17, fibrous
+band which the same tendon receives from the carpal region; 18,
+posterior ulnar (external flexor of the metacarpus); 19, pisiform; 20,
+extensor ossis metacarpi pollicis and extensor primi internodii pollicis
+(oblique flexor of the metacarpus); 21, ulnar portion of the deep flexor
+of the digits; 22, flexor digitorum profundus; 23, 23, tendon of the
+flexor digitorum sublimis (superficial flexor of the phalanges); 24, 24,
+tendon of the flexor digitorum profundus (deep flexor of the phalanges);
+25, sesamoid prominence; 26, suspensory ligament of the fetlock; 27,
+external rudimentary metacarpal.]
+
+In the cat and the dog, the four tendons which result from the division
+of the principal tendon go to the four last digits, and each of them is
+inserted, as in the human species, to the second and third phalanges.
+
+In the pig, the anterior extensor of the phalanges is rather complicated
+in its arrangement. Its fleshy body is divided into four bundles
+terminated by tendons, which in turn divide and join certain digits;
+whence the special names given to each of these fasciculi, commencing
+with the most internal, of: _proper extensor of the great inner toe_;
+_common extensor of the two inner toes_; _common extensor of the two
+outer toes_; and _proper extensor of the great outer toe_.
+
+In the ox, the same muscle is divided into two bundles: the internal
+proceeds to the internal toe, the external is common to the two toes.
+
+In the horse, the tendon of the anterior extensor of the phalanges is
+divided into two parts of unequal bulk. The smaller of these tendinous
+slips, which is the more external, unites at the level of the superior
+part of the metacarpus with the tendon of the muscle which we are about
+to study in the following paragraph (Fig. 75, 16). The larger, after
+having reached the anterior surface of the digit, is attached to the
+anterior aspect of the first and second phalanges, and then forms a
+terminal expansion which is inserted into the pyramidal eminence of the
+third.
+
+At the level of the first phalanx this tendon receives on each of its
+lateral aspects a strengthening band, which proceeds from the terminal
+extremity of _the suspensory ligament of the fetlock_,[26] and crosses
+obliquely downwards and forwards over the surface of the first phalanx
+to join the extensor tendon (Fig. 75, 12).
+
+  [26] See p. 200 for a description of this ligament.
+
+A similar arrangement is found in the ox.
+
+This band is noticeable under the skin which covers the lateral aspects
+of the ham.
+
+As the name indicates, this muscle extends the phalanges, one upon the
+other. It also contributes to the extension of the hand, as a whole, on
+the forearm.
+
+=Extensor Minimi Digiti= (Fig. 73, 10; Fig. 74, 15, 16; Fig. 75, 14,
+15).--This muscle, _the lateral extensor of the phalanges_ of veterinary
+anatomy, situated on the external surface of the forearm, behind the
+common extensor of the digits, arises, as a rule, from the epicondyle
+(dog, cat), or from the external surface of the superior extremity of
+the radius (horse). The tendon succeeding to the fleshy body appears
+towards the lower third of the forearm, and at the level of the wrist
+lies in a groove analogous to that which in man is hollowed out for the
+passage of the corresponding tendon at the level of the inferior
+radio-ulnar articulation. This groove corresponds to the same
+articulation in animals in which the ulna is well developed, such as the
+dog and the cat; but it belongs to the radius when the inferior
+extremity of the ulna does not exist--for example, in the horse. Indeed,
+in this animal the groove in question is found on the external surface
+of the carpal extremity of the radius.
+
+In the dog, the tendon is divided into three parts, which, crossing
+obliquely the tendons of the common extensor of the digits, pass to the
+three external digits, to be inserted by blending with the corresponding
+tendons of the latter into the third phalanges of those digits.
+
+Thus is explained the name of _common extensor of the three external
+digits_ which is sometimes given to this muscle.
+
+In the cat, there is a fourth tendon, which passes to the index-finger,
+so that the name _common extensor of the four external digits_ is in
+this case legitimate, and the lateral extensor of the phalanges is also
+a common extensor, as is the anterior extensor of the phalanges, or
+common extensor of the digits.
+
+In the pig, the tendon, which is single, is inserted into the external
+digit, for which reason it has received the name of the _proper extensor
+of the small external digit_. This muscle is, then, really the homologue
+of that which exists in the human species.
+
+In the ox, it is called the _proper extensor of the external digit_; it
+is as thick as the common extensor.
+
+Finally, in the horse, the muscle is little developed. Its fleshy body,
+thin and flattened from before backwards, becomes distinctly visible
+only below the middle of the forearm. Above, it is enclosed in a limited
+space, bounded in front by the common extensor of the digits, and
+behind by the posterior ulnar; there these two muscles approach each
+other so closely that from the point of view of external form they seem
+to be nearly in contact.
+
+The tendon, after receiving the small fasciculus from the common
+extensor (Fig. 75, 16), as well as a fibrous band emanating from the
+external surface of the carpus (Fig. 75, 17), is situated at the
+external side of the tendon of the anterior extensor of the phalanges,
+and is inserted into the anterior surface of the superior extremity of
+the first phalanx.
+
+This muscle extends the digit or digits into which it is inserted. It
+also assists in the movement of extension of the hand as a whole.
+
+=Posterior Ulnar= (_Extensor carpi ulnaris_) (Fig. 73, 11; Fig. 74, 17;
+Fig. 75, 18).--Designated by veterinary anatomists as the _external
+flexor of the metacarpus_,[27] or _external cubital_, this muscle is
+situated in the posterior region of the external surface of the forearm,
+behind the lateral extensor of the phalanges.
+
+  [27] Certain authors give it the name of _ulnar extensor of the
+       wrist_. It is true that in the human being this is its action;
+       but in quadrupeds, owing to its insertion into the pisiform, it
+       draws the hand into the position of flexion.
+
+It arises from the epicondyle; its fleshy body, thick but flattened, is
+directed vertically towards the carpus, and its tendon is inserted into
+the external part of the superior extremity of the metacarpus, after
+having given off a fibrous band, which takes its attachment on the
+pisiform.
+
+It is inserted, in the cat and the dog, into the superior extremity of
+the fifth metacarpal; in the pig to the external metacarpal; in the ox
+to the external side of the canon-bone; in the horse to the superior
+extremity of the external rudimentary metacarpal.
+
+This muscle flexes the hand on the forearm, and in animals in which the
+radio-carpal articulation permits, by its formation, it inclines the
+hand slightly outwards--that is, abducts it.
+
+=Anconeus= (Fig. 72, 17; Fig. 73, 13).--We have already stated (p. 174)
+that the anconeus is included with the triceps brachialis in zoological
+anatomy, and that veterinary anatomists give it the name of _small
+extensor of the forearm_.[28]
+
+  [28] It is also called by some authors, the _small anconeus_.
+
+In the dog it recalls, as to position, the human anconeus, but with this
+difference--that, in the latter, the anconeus, triangular in outline,
+has one of its angles turned outwards (the epicondyloid attachment) and
+one of its sides turned towards the olecranon. Here it is entirely the
+opposite. The anconeus, similarly triangular, is broader externally. At
+this level it takes its origin from the external border of the humerus,
+the epicondyle, and the external lateral ligament of the articulation of
+the elbow; thence its fibres converge towards the external surface of
+the olecranon, to be there inserted.
+
+It is in relation, anteriorly and inferiorly, with the posterior ulnar
+muscle. It is covered superiorly by the external head of the triceps. In
+the cat the disposition of the anconeus is analogous. But in the other
+quadrupeds with which we are here concerned it is completely covered by
+the external head of the triceps. It really participates in the
+formation of the triceps; and seeing that it takes origin from the
+posterior surface of the humerus at the margin of the olecranon fossa
+(Fig. 72), and proceeds thence towards the olecranon to be inserted, we
+can understand why veterinary anatomists have connected its study with
+that of the posterior muscular mass of the arm.
+
+This muscle is an extensor of the forearm on the arm.
+
+We proceed now to inquire what the deep muscles of the posterior region
+of the human forearm become in quadrupeds: the long abductor of the
+thumb, the short extensor of the thumb, the long extensor of the thumb,
+the proper extensor of the index. We know that in every instance these
+muscles, which are deeply seated at their origin, become superficial
+afterwards.
+
+In quadrupeds, on account of the position in which the forearm is
+placed--viz., pronation--the corresponding muscles occupy the anterior
+aspect of this region.
+
+=Long Abductor of the Thumb= (_Extensor ossis metacarpi pollicis_) =and
+Short Extensor of the Thumb= (_Extensor primi internodii pollicis_)
+(Fig. 73, 14; Fig. 74, 19; Fig. 75, 20).--United one to the other in
+man, blended in quadrupeds, they form in the latter the muscles to which
+veterinary anatomists give the name of _oblique extensor of the
+metacarpus_.
+
+This muscle arises from the median portion of the skeleton of the
+forearm. There it is covered by the common extensor of the digits and
+that of the small digit (anterior extensor and lateral extensor of the
+phalanges). Then, at the internal border of the first of these muscles,
+it becomes superficial, passes downwards and inwards, crosses
+superficially the anterior extensor of the metacarpus, reaches the
+inferior extremity of the radius, and becomes lodged in the most
+internal of the grooves situated on the anterior surface of this
+extremity, passes on the internal side of the carpus, and is inserted
+into the superior extremity of the most internal metacarpal--that is, to
+the first metacarpal, or metacarpal of the thumb--in the dog and cat; to
+the internal rudimentary metacarpal in the horse.
+
+It is an extensor of the metacarpal into which it is inserted; but as,
+if we recall the extreme examples given above, in the dog the first
+metacarpal is not very mobile, and in the horse the internal rudimentary
+metacarpal is absolutely fixed to the bone which it accompanies, it is
+more exact to add that this muscle is principally an extensor of the
+metacarpus as a whole.
+
+And yet, in the cat and the dog, it is also able to adduct the first
+metacarpal bone. It must be understood that this movement would be
+abduction, if the hand could be placed in the position of complete
+supination, as in the human species.
+
+=Long Extensor of the Thumb= (_Extensor secundi internodii pollicis_)
+=and Proper Extensor of the Index= (_Extensor indicis_).--These two
+muscles are blended together by their fleshy bodies, so that the single
+name of _proper extensor of the thumb and index_ is preferable. This
+muscle is but of slight importance from our point of view, for it is
+extremely atrophied, and so much the more as the number of the digits is
+lessened.
+
+It arises, as the preceding, from the skeleton of the forearm, and there
+it is deeply placed. Below, towards the carpus, its tendinous part
+becomes superficial, to end in the following manner:
+
+In the carnivora, the tendon divides into two very slender parts, which
+are inserted into the thumb and the index. In the pig, the tendon is
+blended with that of the common extensor of the internal digits.
+Finally, in the ox and the horse, it is sometimes regarded as being
+blended with the common or anterior extensor of the phalanges. But to us
+it appears more rational to say that it does not exist, which, moreover,
+is explained by the digital simplification of the hand.
+
+
+Internal and Posterior Region
+
+=Pronator Teres= (Fig. 76, 8).--This muscle, as may easily be
+understood, undergoes, as do the supinators, a degree of degeneration in
+proportion to the loss of mobility of the radius on the ulna. In animals
+in which the bones of the forearm are not fused it exists; in those, on
+the other hand, in which this segment has become simply a supporting
+column, it is not developed--at least, in a normal manner.
+
+It is, consequently, found best marked in the dog and the cat.
+
+Forming, as in man, the internal limit of the hollow of the elbow, the
+pronator teres has a disposition analogous to that which characterizes
+the corresponding muscle in the human species. It arises from the
+epitrochlea (internal condyle), proceeds downwards and outwards, and is
+inserted into the middle portion of the body of the radius.
+
+It is into the hollow in front of the elbow, which this muscle
+contributes to limit, that the biceps and the brachialis anticus dip.
+
+In the pig and the ox it is atrophied.
+
+In the horse it does not exist. We may, however, sometimes find it, but
+in an abnormal form. We were able to demonstrate its presence in the
+form of a fleshy tongue situated on the internal side of the elbow
+(Fig. 78) in a horse which we dissected many years ago in the laboratory
+of the School of Fine Arts. Moreover--and the fact seemed to us an
+interesting one--the forearm to which the muscle belonged had an ulna of
+relatively considerable development (Figs. 79 and 80).[29]
+
+  [29] Edouard Cuyer, 'Abnormal Length of the Ulna and Presence of a
+       Pronator Teres Muscle in a Horse' (_Bulletin de la Societe
+       d'Anthropologie_, Paris, 1887).
+
+This muscle is a pronator.
+
+=Flexor Carpi Radialis= (Fig. 76, 10; Fig. 77, 7).--Called by veterinary
+anatomists _the internal flexor of the metacarpus_, this muscle, which
+is found on the internal aspect of the forearm, is situated behind the
+pronator teres when this muscle exists, whilst in the animals which are
+deprived of the latter the flexor carpi radialis has in front of it the
+internal border of the radius, which separates it from the anterior
+extensor of the metacarpus.
+
+It is necessary to add that the flexor carpi radialis is similarly
+separated from the anterior extensor of the metacarpus by the internal
+border of the radius in animals in which the pronator teres exists, but
+then only in that part of the forearm which is situated below this
+latter.
+
+The flexor carpi radialis arises from the epitrochlea. Its fleshy body,
+fusiform in shape, descends vertically, and terminates in a tendon on
+the posterior surface of the bases of the second and third metacarpals
+in the dog and the cat, on the metacarpal of the large internal digit in
+the pig, on the internal side of the metacarpus in the ox, and on the
+superior extremity of the internal rudimentary metacarpal in the horse.
+
+We see clearly, in this latter, a superficial vein which, in the shape
+of a strong cord, passes along the anterior border of the flexor carpi
+radialis; it is the subcutaneous median or internal vein, which, forming
+the continuation of the internal metacarpal vein, joins the venous
+system of the arm, after having crossed obliquely the corresponding part
+of the radius.
+
+=Palmaris Longus.=--This muscle, which exists distinctly in some
+animals, but whose absence is far from being rare in the human species,
+is not developed as a distinct muscle in any of the domestic quadrupeds.
+
+[Illustration: FIG. 76.--MYOLOGY OF THE DOG: LEFT ANTERIOR LIMB,
+INTERNAL ASPECT.
+
+1, Biceps; 2, long extensor of the forearm (supplementary or accessory
+muscle of the great dorsal); 3, triceps, long head; 4, triceps, internal
+head; 5, olecranon; 6, epitrochlea (internal condyle); 7, radial
+extensors (anterior extensor of the metacarpus); 8, pronator teres; 9,
+radius; 10, flexor carpi radialis (internal flexor of the metacarpus);
+11, anterior ulnar (oblique flexor of the metacarpus); 12, superficial
+flexor of the digits; 13, deep flexor of the digits; 14, flexor longus
+pollicis (radial fasciculus of the deep flexor of the digits); 15,
+pisiform bone.]
+
+And yet some authors announce its presence in the dog, and describe it
+as becoming detached, in the form of a cylindrical bundle, from the
+anterior surface of the fleshy mass of the deep flexor of the digits
+(see p. 196) to proceed then by a tendon which divides into two parts,
+to terminate in the palm of the hand, where it blends with the tendons
+of the superficial flexor, which are destined for the third and fourth
+digits.
+
+These authors give to this muscle the name of _palmaris longus_, and
+attribute to it the action of flexing the hand.
+
+=Anterior Ulnar= (_Flexor carpi ulnaris_) (Fig. 73, 16; Fig. 76, 11;
+Fig. 77, 8).--Called by veterinary anatomists the _oblique flexor of the
+metacarpus_, or _internal ulnar_, this muscle occupies the internal part
+of the posterior aspect of the forearm in the ox and the horse, while in
+the dog it occupies rather the external part.
+
+This difference arises from the fact that in this latter, as in man, the
+anterior ulnar is separated from the flexor carpi radialis by an
+interval in which we see, on the internal aspect of the forearm, just at
+the level of the elbow, the flexors of the digits. This interval is so
+much the wider as there is no palmaris muscle to subdivide its extent
+(Fig. 81). In the horse, the interval in question does not exist. In
+this animal, indeed, the anterior ulnar is in contact with the radial
+flexor, so that this muscle can occupy only a region belonging rather to
+the internal surface of the forearm (Fig. 82).
+
+In the dog the anterior ulnar is in contact with the posterior ulnar.
+This relation recalls that which is found in man, where the two muscles
+are merely separated by the crest of the ulna (Fig. 81). But in the
+horse, in which the anterior ulnar has, so to speak, slid towards the
+internal aspect, this muscle is separated above from the posterior
+ulnar, and it is in the interval separating these two muscles that we
+are able to perceive, but this time at the back of the forearm, the
+muscular mass of the flexors of the digits (Fig. 82).
+
+[Illustration: FIG. 77.--MYOLOGY OF THE HORSE: ANTERIOR LIMB, LEFT SIDE,
+INTERNAL ASPECT.
+
+1, Long extensor of the forearm (supplementary or accessory muscle of
+the latissimus dorsi); 2, radialis muscles (anterior extensor of the
+metacarpus); 3, tendons of extensor ossis metacarpi pollicis extensor
+primi internodii pollicis united (oblique extensor of the metacarpus);
+4, tendon of extensor communis digitorum (anterior extensor of the
+phalanges); 5, strengthening band from the suspensory ligament of the
+fetlock; 6, internal surface of the radius; 7, flexor carpi radialis
+(internal flexor of the metacarpus); 8, anterior ulnar (oblique flexor
+of the metacarpus); 9, pisiform bone; 10, 10, tendon of the superficial
+flexor of the digits (superficial flexor of the phalanges); 11, 11,
+tendon of the deep flexor of the digits (deep flexor of the phalanges);
+12, sesamoid prominence; 13, suspensory ligament of the fetlock; 14,
+internal rudimentary metacarpal.]
+
+The anterior ulnar arises above from the epitrochlea and the olecranon;
+thence it is directed towards the carpus, to be inserted into the
+pisiform bone. It proceeds therefore from the inner side of the elbow to
+the outer side of the upper part of the hand; it consequently crosses
+the posterior surface of the forearm obliquely. This is why, as we have
+pointed out above, it receives the name of the oblique flexor of the
+metacarpus.
+
+It is not unprofitable to recall in this connection that there is an
+internal flexor of the metacarpus, which is the flexor carpi radialis;
+and an external flexor of the metacarpus, which is the posterior ulnar
+(in human anatomy, extensor carpi ulnaris). It is between these two
+muscles that we find the oblique flexor--the anterior ulnar which we
+have just been studying.
+
+This muscle flexes the hand on the forearm.
+
+=Superficial Flexor of the Digits= (_Flexor digitorum sublimis_) (Fig.
+76, 12; Fig. 77, 10, 10).--This muscle arises from the epitrochlea;
+thence it passes towards the hand, becomes tendinous, passes in a groove
+on the posterior aspect of the carpus, and terminates on the palmar
+surface of the phalanges in furnishing a number of tendons proportioned
+to the digital division of the hand. Whatever the number, to which we
+will again refer, each tendon is attached to the second phalanx, after
+bifurcating at the level of the first, so as to form a sort of ring,
+destined to give passage to the corresponding tendon of the deep flexor.
+This ring and this passage have gained for the muscle the name of
+_perforated flexor_.
+
+In the dog and the cat the principal tendon is divided into four parts,
+which go to the four last digits.
+
+In the ox it is divided into two parts only; as, moreover, in the pig,
+whose superficial flexor is destined for the two large digits only, the
+lateral digits receiving no part of it.
+
+Finally, in the horse the tendon is single.
+
+We have previously pointed out that in the carnivora this muscle is
+visible on the internal and posterior aspects of the forearm, in the
+interval which is limited in front by the flexor carpi radialis and
+behind and outside by the anterior ulnar.
+
+Certain details are still to be added to the description of this
+muscle. We will enter on an analysis of them after we have given some
+indications relative to the following muscle:
+
+=Deep Flexor of the Digits= (_Flexor digitorum profundus_) (Fig. 75, 21,
+22; Fig. 76, 12; Fig. 77, 11, 11).--This muscle is covered by the
+superficial flexor. It arises from the epitrochlea, from the radius, and
+from the ulna, either from the olecranon process--as in the ox, pig, and
+horse--or from almost the whole extent of the shaft of the same bone, as
+in the cat and dog.
+
+[Illustration: FIG. 78.--LEFT ANTERIOR LIMB OF THE HORSE: INTERNAL
+ASPECT.
+
+1, Internal flexor of the metacarpus or great palmar; 2, inferior part
+of the biceps; 3, inferior part of the brachialis anticus; 4, internal
+lateral ligament of the elbow; 5, pronato teres muscle.]
+
+The radial fasciculus represents in the domestic quadrupeds the long
+proper flexor muscle of the thumb in man. For this reason we shall
+describe the muscle afresh in the following paragraph:
+
+The fleshy bundles of which we have just spoken terminate in a tendon
+which afterwards divides into slips, the number of which is in
+proportion to the digital division of the hand. These slips then pass
+through the slit or _buttonhole_ in the tendon of the superficial
+flexor, and proceed to terminate on the third phalanx; hence the name of
+_perforating_, which is also given to the deep flexor of the digits.
+
+In the dog and the cat the tendon is divided into five portions, each of
+which proceeds to one of the digits. The internal tendon, which is
+destined for the thumb, terminates on the second phalanx of this digit.
+
+In the pig the tendon divides into four tendons destined for the four
+digits.
+
+In the ox there are but two tendons.
+
+In the horse the tendon is single.
+
+As their names indicate, these muscles, both superficial and deep, flex
+the digits. In addition to this, they flex the hand on the forearm.
+
+We mentioned above that certain details relative to the superficial
+flexor must be analyzed in a special way. We now add that this should
+also be done with regard to the deep flexor. The point in question is
+the arrangement which the tendons of these muscles present at the level
+of the palmar region of the hand.
+
+It is easy, in the case of the dog or the cat, to picture to one's self
+this arrangement, especially if we recollect that which exists in the
+human species. The tendons of the flexors are placed on a kind of
+muscular bed formed by the union of the muscles of the region, but,
+moreover, from the point of view of external form, these tendons are not
+of very great importance.
+
+But in the ox and the horse it is quite otherwise. From the
+simplification of the skeleton of the hand, and the reduction of the
+number of movements which the bones that form it are able to execute,
+there naturally results a diminution of its muscular apparatus. Apart
+from the existence of muscular vestiges of but little importance, we can
+say that, in reality, the hand does not possess any muscles. On its
+palmar aspect are found only the tendons of the flexors of the digits,
+and as these tendons are large, and the hand long, they give origin to
+external forms which it is necessary to examine.
+
+[Illustration: FIG. 79.--LEFT ANTERIOR LIMB OF THE HORSE: EXTERNAL
+ASPECT.
+
+1, Ulna of abnormal length.]
+
+[Illustration: FIG. 80.--LEFT ANTERIOR LIMB OF THE HORSE: EXTERNAL
+ASPECT.
+
+1, Normal ulna.]
+
+In the horse, which we take as a type, the tendons of the flexors, after
+being retained in position at the carpus by a fibrous band, the _carpal
+sheath_, which recalls the anterior annular ligament of the human
+carpus, and having passed this region, descend vertically, remaining
+separated from the posterior surface of the metacarpus, so that the skin
+sinks slightly on the lateral parts in front of the thick cord which
+these tendons form. This cord is known by the name of _tendon_.
+
+The flexors then reach the fetlock, and occupy the groove formed by the
+peculiar arrangement of the two large sesamoid bones. They are retained
+in position at this level by a fibrous structure, which forms the
+metacarpo-phalangeal sheath. They then reach the phalanges, being
+directed obliquely downwards and forwards, as, moreover, the latter are
+also inclined. Then the tendon of the superficial flexor divides into
+two slips, which are inserted into the second phalanx, between which
+slips passes the tendon of the deep flexor, which in its turn goes to be
+inserted, in the form of an expansion, into the semilunar crest, by
+which the inferior surface of the third phalanx is divided into two
+parts.[30]
+
+  [30] See, as regards this crest, in the paragraph relative to the hoof
+       of the solipeds, the figures which represent the third phalanx,
+       viewed on its inferior surface (Figs. 101 and 102, p. 258).
+
+The part which these tendons play is of great importance in the large
+quadrupeds.
+
+These tendons, in fact, in addition to the action determined by the
+contraction of the fleshy fibres to which they succeed, maintain the
+angle formed by the canon-bone and the phalangeal portion of the hand,
+and prevent its effacement under the weight of the body during the time
+of standing. Their strong development, and the position they occupy,
+make this understood, without it being necessary to insist on it
+further.
+
+We mentioned above that the 'tendon' descends vertically from the carpus
+towards the fetlocks. This is as it should be. But, in some horses, it
+is oblique downwards and backwards, so that the canon, instead of being
+of equal depth from before backwards in its whole length, is a little
+narrower in its upper part.
+
+This results from the fact that the tendons of the flexors, too firmly
+bound by the carpal sheath, gradually separate as they pass from the
+metacarpus, going to join the fetlock; hence the obliquity pointed out
+above. This abnormality producing a deleterious result, in the sense
+that the tendinous apparatus acts with less strength as an organ of
+support, it constitutes a defect of conformation which is expressed by
+saying that the tendon has 'failed.'
+
+=Long Proper Flexor of the Thumb= (_Flexor longus pollicis_) (Fig. 76,
+14).--As we have already pointed out, this muscle is represented in
+quadrupeds by the radial bundle of the deep flexor of the digits, so
+that the two muscles are in reality blended the one to the other. This
+union is sometimes found, but only as an abnormality, in the human
+species. We have met some examples of this in the course of our
+dissections.
+
+=Pronator Quadratus.=--This muscle conforms to the general law which we
+have already pointed out in connection with those which have for their
+action the rotation of the radius around the ulna. We remember, indeed,
+that when the bones of the forearm are fused with one another, the
+muscles which are destined to produce a mobility which has then become
+impossible disappear at the same blow.
+
+[Illustration: FIG. 81.--DIAGRAM OF THE POSTERIOR PART OF A TRANSVERSE
+SECTION PASSING THROUGH THE MIDDLE OF THE LEFT FORE-LIMB OF THE DOG:
+SURFACE OF THE INFERIOR SEGMENT OF THE SECTION.
+
+1, Radius; 2, ulna; 3, posterior ulnar; 4, anterior ulnar; 5, great
+palmar (_flexor carpi radialis_); 6, flexors of the digits.]
+
+[Illustration: FIG. 82.--DIAGRAM OF A HORIZONTAL SECTION OF THE MIDDLE
+OF THE FOREARM OF THE LEFT LEG OF THE HORSE: SURFACE OF THE INFERIOR
+SEGMENT OF THE SECTION.
+
+1, Radius; 2, ulna; 3, posterior ulnar; 4, anterior ulnar; 5, great
+palmar (_flexor carpi radialis_); 6, flexors of the digits.]
+
+For this cause we do not find the square pronator in either the ox or
+the horse, but can demonstrate its presence in the dog and the cat.
+
+It is very deeply situated. This is why, and also on account of the plan
+which we have traced for ourselves, we will simply say that it is
+situated on the postero-internal aspect of the skeleton of the forearm,
+and that it extends from the ulna to the radius.
+
+It seems to us, however, sufficiently interesting to add that, instead
+of occupying, as in the human species, the inferior fourth of the two
+bones, it extends, particularly in the dog, over their whole length,
+with the exception of their superior and inferior extremities.
+
+
+Muscles of the Hand
+
+We will first recall that, in man, the palm of the hand is divided into
+three regions: a median palmar region, which is occupied by the tendons
+of the flexors of the digits, the lumbricales, and, deeply, by the
+interosseous muscles; an external region, or thenar eminence, formed by
+the muscles destined for the movements of the thumb; an internal region,
+or hypothenar eminence, which contains the muscles proper to the small
+digit and the palmar cutaneous muscle.
+
+These muscles are found, more or less developed, in the dog and the cat.
+
+In the ox and the horse we meet with no vestige of the muscles of the
+thenar or hypothenar eminences. Nevertheless, in these animals we find
+the muscles which belong to the central region of the palm. We refer to
+the lumbricales and the interosseous.
+
+Although this fact has no relation to the object of our study, it
+appears to us interesting to announce that there are traces of the
+lumbricales found in the solipeds. These muscles are represented by two
+fleshy bundles, situated one on each side of the tendon of the deep
+flexor, above the ring of the tendon of the superficial flexor. These
+small muscles are continued as slender tendons, which become lost in the
+fibrous tissue of the _spur_, which is the horny process situated at the
+posterior part of the fetlock, and which is covered by the hairs, more
+or less abundant, which constitute the _wisp_.
+
+As for the interosseous muscles, they are represented by the _suspensory
+ligament of the fetlock_, and by two other small muscles, tendinous
+throughout, which are situated between the principal metacarpal and the
+rudimentary ones.
+
+The suspensory ligament of the fetlock is considered an interosseous
+muscle, on account of the red fleshy striations which it contains, and
+from certain relations which it forms with the tendon of the common
+extensor of the digits or anterior extensor of the phalanges. This
+ligament (Fig. 75, 26; Fig. 77, 13), which plays an important part in
+the standing position as a support of the foot, is a fibrous band
+situated between the tendons of the flexors of the digits and the
+principal metacarpal. It arises above, from the second row of the
+carpals, descends towards the fetlock, where it divides into two
+branches, which are inserted into the large sesamoid bones. At the same
+level, this ligament gives off two fibrous bands which, passing
+downwards and forwards, join the tendon of the anterior extensor of the
+phalanges, blending with it, after having each crossed one of the
+lateral aspects of the pastern. We have already referred to these bands
+(p. 183).
+
+It is with these latter that are blended the long and slender tendons
+which form in a great measure the two other interosseous muscles
+previously described.
+
+A ligament of the same kind is found in the ox (Fig. 74, 23).
+
+
+MUSCLES OF THE POSTERIOR LIMBS
+
+
+Muscles of the Pelvis
+
+The muscles which specially interest us in this region, because of their
+superficial position, are the gluteus maximus and the gluteus medius. As
+for the gluteus minimus, it is deeply situated, and more or less sharply
+marked off from the second of the preceding muscles.
+
+Inasmuch as the gluteus medius is more simple in arrangement than the
+maximus, and will aid us in arranging our ideas in connection with the
+latter, it is with the study of it that we will commence.
+
+=Gluteus Medius= (Fig. 68, 29; Fig. 69, 26; Fig. 70, 35).--This muscle,
+as in man, occupies the external iliac fossa. But this latter being
+directed differently in the digitigrades and the ungulates, as we have
+pointed out in the section on osteology (see pp. 91 and 99), the muscle
+in question has consequently not the same direction in the two groups of
+animals, being turned outwards in the first, and upwards in the second.
+
+It is the thickest of the glutei, and gives to the region which it
+occupies a rounded form.
+
+From the iliac fossa from which it arises the fleshy fibres are directed
+towards the femur, to be inserted into the great trochanter. It is
+covered by an aponeurosis, and in part by the great gluteal. It
+completely covers the small gluteal, which veterinary anatomists
+designate by the name of the _deep gluteal_.
+
+In the carnivora it does not pass in front of the iliac crest, but, in
+the ox, and more particularly in the horse, it is prolonged anteriorly,
+and thus covers, to a certain extent, the muscles of the common mass.
+
+When it contracts, taking its fixed point at the pelvis, the gluteus
+medius extends the thigh, which it is also able to abduct. If, on the
+other hand, its fixed point is on the femur, it acts on the trunk, which
+it raises, producing oscillating movements of the pelvis. It contributes
+in this way to the action of rearing. We also see it distinctly appear
+by the prominence which it produces in the dog, which, according to the
+time-honoured phrase, _fait le beau_.
+
+=Gluteus Maximus= (Fig. 68, 28; Fig. 69, 25; Fig. 70, 33, 34).--The
+great gluteal muscle, further designated in veterinary anatomy the
+_superficial gluteal_, is proportionately less developed in quadrupeds
+than in man. Indeed, in the latter, where it is of very great thickness,
+its volume is due to the important function which it fulfils in
+maintaining the biped attitude.
+
+In quadrupeds it contributes to form the superficial part of the crupper
+and the external surface of the thigh. It is divided into two parts: one
+anterior, the other posterior.
+
+With regard to this latter, it will be necessary to indicate how it has
+been sometimes regarded, and to what portion of the muscular system in
+man it corresponds. But we believe that it is better to see beforehand,
+without any preconceived idea, how these two parts are arranged.
+
+In the dog, the anterior portion of the gluteus maximus arises from the
+sacrum, while some fibres situated further forward arise from the
+surface of the gluteus medius, near the iliac spine, and from the tensor
+of the fascia lata with which these fibres are blended. The posterior
+portion, united to the preceding--that is to say, to those of its fibres
+which arise from the sacrum--takes its origin from the first coccygeal
+vertebra. These two portions are directed towards the femur, to be
+inserted into the great trochanter, and to the external branch of the
+superior bifurcation of the linea aspera.
+
+In the cat, the posterior bundle is less definitely blended with the
+anterior. By a long and slender tendon which, behind, turns around the
+great trochanter, and passes along the surface of the fascia lata, it
+proceeds to join the knee-cap.
+
+In the pig, the posterior portion is much more developed.
+
+In the horse, the anterior portion arises from the internal iliac spine
+(posterior in man), from the external iliac spine (anterior in man),
+and, between these two osseous points, from the aponeurosis, which
+covers the gluteus medius. Between these two origins the muscle is
+deeply grooved, so that the tendency is to divide into two portions,
+each of which is directed towards one of the iliac angles. In this
+groove the gluteus medius is to be seen.
+
+The fleshy bundles converge, and are directed towards the external
+aspect of the femur, to be inserted into the osseous prominence known as
+the third trochanter, after passing beneath the fleshy fibres of the
+posterior portion. The latter, which is more considerable than the
+preceding portion, arises above from the sacral crest, from the
+aponeurosis which envelops the coccygeal muscles, from the sacro-sciatic
+ligament, and from the tuberosity of the ischium. From this origin it
+passes downwards, expands, then, describing a curve with the convexity
+behind, it becomes narrowed, and proceeds to be inserted by a deep
+fasciculus into the third trochanter, to the fascia lata, and, lastly,
+to the knee-cap by the inferior part of its tendon.
+
+Above, its posterior border is covered by the semi-tendinosus;
+interiorly, the same border is in relation with the biceps femoris.
+
+In the ox, the two parts of the great gluteal muscle are blended
+together.
+
+The long and broad fleshy band which they form arises in a manner
+corresponding to that which we have just indicated in connection with
+the horse, except that it has no attachment to the femur. The fascia
+lata adheres strongly to its anterior border for a considerable length.
+The form of the superior border of the great gluteal muscle of this
+animal differs from that of the analogous portion in the horse. This
+difference results from the peculiar aspect which the corresponding
+region of the pelvis presents, and from the fact that, in the ox, as the
+semi-tendinosus does not cover the portion of the great gluteal which
+arises from the tuberosity of the ischium, the attachments of this
+muscle to the sacro-sciatic ligament are uncovered.
+
+Its descending portion, as a whole, has a rectilinear form, and does not
+form a curve such as we indicated in the case of the horse.
+
+The anterior portion of the great gluteal flexes the thigh. As regards
+the posterior portion, it extends the thigh, and abducts it.
+
+The action of this latter portion is particularly interesting as regards
+the horse, because of the great development of the muscular mass which
+this region presents in this animal. If the muscle takes its fixed point
+above, it acts, in the extension of the thigh during walking, by
+projecting the trunk forward during the whole time that the hind-limb to
+which it belongs is in contact with the ground. If, on the contrary, it
+takes its fixed point below, it makes the pelvis describe a see-saw
+movement, upwards and backwards, on the coxo-femoral articulation, and
+so contributes to the action of rearing.
+
+Now that we have a knowledge of the disposition of the great gluteal
+muscle, the moment has come to inquire what is the signification of its
+posterior portion. The action of the anterior part being clearly
+comparable to the human great gluteal, there can be no doubt as regards
+the homology of this portion, so we will not insist on it further.
+
+Of the posterior portion it is wholly different, for it is the homologue
+of a fleshy bundle annexed to the great gluteal of man, but which is not
+developed except as an abnormality.
+
+Indeed, we sometimes find, placed along the inferior border of the great
+gluteal, a fleshy fasciculus, separated from this muscle by a slight
+interspace. This fasciculus, long and narrow, takes origin from the
+summit of the sacrum, or the coccyx, and goes to partake of the femoral
+insertions of the muscle which it accompanies. We further note a muscle
+of the same kind, and presenting the same aspect, which comes from the
+tuberosity of the ischium. Notwithstanding the difference which exists,
+it is this abnormal fasciculus of man which in the quadrupeds here
+studied is considered as constituting the posterior portion of the great
+gluteal.
+
+Bourgelat, considering this posterior portion as belonging to the biceps
+cruris, to which, it is true, it adheres, forms of them a muscle which
+he designates under the name of the _long vastus_. The anterior
+fasciculus of this long vastus is none other than the posterior portion
+of the great gluteal which we have just been studying.
+
+
+Muscles of the Thigh
+
+These muscles are divided into three regions: posterior, anterior, and
+internal.
+
+In a corresponding manner to that which we described in connection with
+the arm, the thigh is applied to the side of the trunk, and is free,
+more or less, only at the level of the inferior part.
+
+Further, by reason of this shortening of the femur, the great gluteal
+muscle, which is elongated in the ox and the horse, for example,
+occupies in part the region corresponding to that which in man is
+occupied by the muscles of the thigh, which here are reduced in length.
+In other words, they are not superposed, as in the human species, but
+juxtaposed. This is what we will verify further on.
+
+The thigh, as a whole, is flattened from without inwards, its transverse
+diameter being less in extent than its antero-posterior. Its external
+surface is slightly rounded; that is, of course, in quadrupeds with
+sufficiently well-developed muscles. Its internal surface is known as
+the _flat of the thigh_.
+
+
+Muscles of the Posterior Region
+
+It is not unprofitable to recall to mind what muscles form the
+superficial layer of this region in the human being. They are the biceps
+cruris, semi-tendinosus, and semi-membranosus. We now proceed to
+discover their analogues in quadrupeds.
+
+=Biceps Cruris= (Fig. 68, 30; Fig. 69, 27; Fig. 70, 36).--It is this
+which, according to Bourgelat, forms the central and posterior portions
+of the long vastus muscle which we have mentioned above.
+
+We know that the biceps of man is so named from the two portions which
+form its upper part. In domestic quadrupeds, and also in the majority of
+the mammals, this muscle is reduced to a single portion, that which
+comes from the pelvis. It is therefore the portion which arises from the
+femur which does not exist. This condition is sometimes found as an
+abnormality in the human species.
+
+The biceps arises from the tuberosity of the ischium; hence it is
+directed, widening as it goes, towards the leg, where it terminates by
+an aponeurosis which blends with the fascia lata and the aponeurosis of
+the leg, and then proceeds to be attached to the anterior border or
+crest of the tibia. By its inferior portion it limits externally the
+posterior region of the knee--the popliteal space.
+
+A fibrous intersection traverses the biceps in its whole length, with
+the result that the muscle looks as if formed of two portions, one of
+which is situated in front of the other.
+
+In the dog and the cat it also arises from the sacro-sciatic ligament.
+At this level its contour is distinguishable from that which corresponds
+to the gluteal muscles, so that we there find two prominences one above
+the other. The superior is formed by the gluteal muscles; the inferior
+corresponds to the tuberosity of the ischium. The two prominences are
+separated by a depression, from which the biceps emerges. We draw
+attention to this form, the character of which is so expressive of
+energy in the carnivora.
+
+In these animals the biceps is inserted, by its anterior fibres, into
+the articulation of the knee, while in the rest of its extent it covers
+in great measure by its aponeurosis the external aspect of the leg.
+
+In the pig, the biceps is but slightly marked off from the posterior
+part of the great gluteal. In the ox, the division between these two
+muscles is a little more distinct.
+
+In the horse, the sciatic origin of the biceps is covered by the
+semi-tendinosus, so that it only becomes free lower down, to appear in
+the space limited behind by the semi-tendinosus, and in front by the
+posterior part of the gluteus maximus.
+
+When the biceps contracts, taking its fixed point from above, it flexes
+the leg and helps to extend the thigh. If, on the other hand, it takes
+its fixed point from below, it lowers the ischium, makes the pelvis
+undergo a see-saw movement, and acts thus in the movement of rearing. It
+is sometimes called, on account of one of its actions, and the position
+which it occupies, the 'external flexor, or peroneal muscle of the leg.'
+
+=Semi-tendinosus= (Fig. 68, 31; Fig. 70, 37; Fig. 87, 1; Fig. 88, 1;
+Fig. 89, 28).--This muscle forms the contour of the thigh posteriorly,
+so that when the latter is viewed from the side, it is the
+semi-tendinosus above all that forms the outline. But, as we shall soon
+see, it is in this case more distinct above than below, because of the
+deviation which it undergoes in order to occupy by its inferior part the
+internal side of the leg.
+
+In the dog, the cat, and the ox, the semi-tendinosus arises from the
+tuberosity of the ischium only, as in the human species. In the pig, it
+also takes origin higher up from the sacro-sciatic ligament and the
+coccygeal aponeurosis. In the horse, it extends still further, for it is
+also attached to the crest of the sacrum.
+
+The indication of these origins is of importance from the point of view
+of external form, and to convince ourselves of this it is sufficient to
+compare, in the ox and the horse, the region of the pelvis situated
+below the root of the tail. In the ox, whose semi-tendinosus arises from
+the tuberosity of the ischium only, this region is depressed, and the
+cavity which is formed at this level is limited behind by the
+tuberosity, which we know is very thick and prominent above. This causes
+the superior part of the crupper to be less oblique than in the horse.
+This characteristic is more especially marked in the cow, the bull
+having this region of a more rounded form.
+
+In the horse, on account of the semi-tendinosus ascending to the coccyx,
+and even to the sacrum, the depression in question does not exist, and
+the presence of the tuberosity of the ischium is only slightly revealed.
+
+Descending from the origin indicated above, and inclining more and more
+inwards, the semi-tendinosus proceeds to blend with the aponeurosis of
+the leg, to be inserted into the anterior border of the tibia, after
+crossing over the internal surface of the latter. It forms the internal
+boundary of the popliteal space.
+
+When this muscle contracts, taking its fixed point at the pelvis, it
+flexes the leg. If, on the other hand, it takes its fixed point at the
+tibia, it makes the pelvis describe a see-saw movement, and acts
+accordingly in the movement of rearing.
+
+It is sometimes named the 'internal or tibial flexor of the leg,' in
+opposition to the crural biceps, which, as stated above, is then the
+external flexor of the same region.
+
+=Semi-membranosus= (Fig. 68, 32; Fig. 87, 2; Fig. 88, 2).--This muscle,
+situated on the inner side of the semi-tendinosus, can be seen only when
+the thigh is regarded on its posterior aspect.
+
+It is only by reason of the homology of situation with the corresponding
+muscle in man that we give the name under which we are studying it;
+indeed, its structure is different, for it does not present the long,
+broad, aponeurotic tendon which, in its superior part, characterizes
+this muscle in the human species.
+
+It arises above from the inferior surface of the ischium, and from the
+tuberosity of the same bone. In the pig, and especially in the horse, it
+passes further upwards, to arise from the aponeurosis of the coccygeal
+muscles. So that if we compare it with that of the ox, which does not
+extend beyond the ischium, we find that it is associated with the
+semi-tendinosus in determining the difference of aspect to which we have
+already called attention in connection with the region of the pelvis
+situated below the root of the tail.
+
+The semi-membranosus is then directed downwards and forwards, to take
+its place on the internal surface of the thigh, where it is partly
+covered by the gracilis muscle. It is inserted in the following manner:
+
+In the dog and the cat it is divided into two parts, anterior and
+posterior. The first, the more developed, is attached to the internal
+surface of the inferior extremity of the femur; the second to the
+internal tuberosity of the tibia.
+
+The same arrangement occurs in the ox.
+
+In the horse it is inserted into the internal surface of the internal
+condyle of the femur.
+
+The semi-membranosus is an extensor of the thigh when it takes its fixed
+point at the pelvis; it is also an adductor of the lower limb. If it
+takes its fixed point below it assists in the action of rearing.
+
+It is now necessary for us, especially as regards the horse, to add some
+indications relative to the exterior forms of the region constituted by
+the semi-membranosus and semi-tendinosus. These two muscles form, by
+their union, a surface contour, slightly projecting and of elongated
+form, which occupies the posterior border of the thigh, the contour
+corresponding to the region known as the _buttock_, in spite of the
+fact that none of the gluteal muscles take any part in the structure of
+this region. But the appearances, to a certain extent, justify the
+preservation of this name. Indeed, because of the groove which separates
+the gluteal region of one side from that of the opposite side, and from
+the position of the anal orifice in the superior part of this groove, we
+may admit the name which, in hippology, has been given to this part of
+the thigh.
+
+In addition to the reasons just given, and which are justified
+especially by the position occupied by the muscular mass formed by the
+union of the two muscles, there is another which, this time, has a
+relation to a certain detail of form. In the superior part of the
+convexity, which the gluteal region describes in the greater part of its
+extent, there is found a more salient point, greatly accentuated in lean
+animals, due to the presence of the tuberosity of the ischium; it is the
+_point_ or _angle of the buttock_. At this level, and near the median
+line, the semi-membranosus, not aponeurotic, but fleshy, and even
+thicker there than anywhere else, sometimes produces a sharply localized
+prominence. And as this prominence is situated on the outer side of the
+anal orifice, the resemblance to a small 'buttock' is still more marked.
+
+In lean horses a deep groove separates the mass formed by the
+semi-membranosus and semi-tendinosus from that of the other muscles of
+the thigh situated more in front; this groove is known by a name which
+in this case is remarkably expressive--that of the 'line of poverty.'
+
+If we examine the gluteal region as a whole by looking at the thigh from
+the side, we plainly see the graceful curve produced by the general
+convexity above indicated. We return to this point, in order to add
+that, in its lower part, this curve alters its character; that is to
+say, it is replaced by a slight concavity. This, which is designated
+under the name of _the fold of the buttock_, is situated close to the
+level of articulation of the leg with the thigh-bone.
+
+
+Muscles of the Anterior Region
+
+First we recall that in man the anterior muscles of the thigh are: the
+triceps cruris, the tensor of the fascia lata, and the sartorius.
+
+=Triceps Cruris= (Fig. 8, 36; Fig. 69, 31; Fig. 70, 41; Fig. 84, 2; Fig.
+87, 3; Fig. 88, 3).--This muscle, which occupies the greater part of the
+space between the pelvis and the anterior aspect of the femur, consists
+of three parts: an external, or vastus externus; an internal, or vastus
+internus; and a median or long portion, or rectus femoris. This division
+accordingly recalls that which characterizes the human triceps cruris.
+Furthermore, as in the case of the latter, the vastus externus and the
+vastus internus take their origin from the shaft of the femur, while the
+long portion arises from the pelvis. The _vastus externus_ arises from
+the external lip of the linea aspera of the femur (or from the external
+border of the posterior surface of this bone in the ox and the horse, in
+which the linea aspera, considerably widened, especially in the latter,
+forms a surface), and from the external surface of the shaft of the
+femur. From this origin its fibres pass downwards and forwards, to be
+inserted into the tendon of the long portion of the muscle and into the
+patella.
+
+In the dog and the cat the vastus externus is the most voluminous of the
+three portions which constitute the triceps muscle. It is covered by the
+fascia lata; but notwithstanding this, its presence is revealed by a
+prominence which occupies the external surface of the thigh, and
+surmounts, in the region of the knee, the more slightly developed one
+which is produced by the knee-cap.
+
+The _vastus internus_, situated on the inner surface of the thigh, takes
+its origin from the corresponding surface of the femur, and proceeds
+towards the patella.
+
+The rectus femoris arises from the iliac bone, above the cotyloid
+cavity; its fleshy body, which is fusiform, and situated in front of and
+between the two vasti muscles, is directed towards the patella, into
+which it is inserted by a tendon, which receives the other two
+portions.
+
+It is covered in front by the tensor of the fascia lata, and contributes
+with the vastus externus to form the upper prominence of the knee.
+
+The ligamentous fibres, which, as in man, unite the knee-cap to the
+tibia, transmit to this latter the action determined by the contraction
+of the triceps. This muscle is an extensor of the leg. Furthermore, the
+rectus femoris, or long portion, acts as a flexor of the thigh.
+
+=Tensor Fascia Lata= (Fig. 68, 34, 36; Fig. 69, 30, 31; Fig. 70,
+40).--This muscle, generally larger in quadrupeds than in man, is flat
+and triangular, and occupies the superior and anterior part of the
+thigh.
+
+It arises from the anterior iliac spine (inferior in carnivora, external
+in the ox and the horse); it is prolonged downwards by an aponeurosis
+(fascia lata) which occupies the external aspect of the thigh, proceeds
+to be inserted into the patella and blend with the aponeurosis of the
+biceps muscle.
+
+It covers the rectus and vastus externus portions of the triceps cruris;
+it is also in relation with the gluteal muscles.
+
+The tensor of the fascia lata flexes the thigh, and serves to raise the
+lower limb as a whole.
+
+=Sartorius= (Fig. 68, 35; Fig. 87, 4, 5; Fig. 88, 5).--This muscle, long
+and flattened, is called by veterinarians _the long adductor of the
+leg_.
+
+Before beginning the study of its position in quadrupeds, it is
+necessary to remember that in man, where the thigh has a form almost
+conical, the sartorius commences on the anterior face of this latter,
+and is directed downwards and inwards to reach the internal surface of
+the knee.
+
+But now let us suppose the thigh flattened from without inwards; there
+will evidently result from this a change in situation with regard to the
+muscle in question. In fact, when this supposition is admitted, it is
+easy to imagine that in a great part of the extent in which the
+sartorius is normally anterior it will become internal. This is why,
+these conditions being realized in quadrupeds, we shall find that, in
+some of them, the sartorius is situated on the aspect of the thigh which
+is turned to the side of the trunk.
+
+In the dog and the cat it arises from the anterior iliac spine, and from
+the half of the border of the bone situated immediately below it; but
+the fibres from this second origin being hidden by the tensor of the
+fascia lata, on the inner side of which they are situated, viewing the
+external surface of the thigh, the muscle seems to arise from the iliac
+spine only.
+
+The sartorius in these animals is divided into two parts, which, in
+general, are placed in contact. One of these fasciculi is anterior; the
+other is situated further back. The first is visible on the anterior
+border of the thigh, in front of the tensor of the fascia lata, but
+below it inclines inwards; in its superior part also, a small extent of
+the internal surface is occupied by it. The second, which, as we have
+said, is situated further back, belongs wholly to the inner surface of
+the thigh; it is this portion which arises from the inferior border of
+the ilium (this is the homologue of the anterior border of the human
+iliac bone).
+
+The two fasciculi then pass towards the knee, being in relation with the
+rectus and the vastus internus of the triceps. The anterior fasciculus
+is inserted into the patella. The posterior unites with the tendons of
+the gracilis (see below) and semi-tendinosus, and then proceeds to be
+inserted into the superior part of the internal surface of the tibia.
+
+On account of their different insertions these two parts receive the
+names of _the patellar sartorius_ and _tibial sartorius_ respectively.
+
+In the ox and the horse the sartorius is still more definitely situated
+on the internal surface of the thigh. Consisting of a single fasciculus,
+representing the tibial sartorius of the cat and the dog, it arises in
+the abdominal cavity from the fascia covering the iliac muscle, then
+passes under the crural arch, and terminates, by an aponeurosis which
+blends with that of the gracilis, on the inner fibres of the patellar
+ligament. In short, the sartorius is of interest to us in the carnivora
+only, and especially on account of its anterior or patellar fasciculus.
+
+It is an adductor of the leg and a flexor of the thigh.
+
+
+Muscles of the Internal Region
+
+The ilio-psoas pectineus and the adductors which we study in man, in
+connection with the internal aspect of the thigh, offer little of
+interest from the point of view of external form in quadrupeds; it is
+for this reason that we will disregard them.
+
+The gracilis alone merits description.
+
+=Gracilis= (Fig. 87, 9; Fig. 88, 6).--Designated in veterinary anatomy
+under the name of _the short adductor of the leg_, this muscle, expanded
+in width, occupies the greater part of the internal surface of the
+thigh, _or flat of the thigh_, as this region is also called. Let us
+imagine, in man, the internal surface of the thigh broader, and the
+internal rectus more expanded, and we shall have an idea of the same
+muscle as it exists in quadrupeds.
+
+The gracilis arises from the ischio-pubic symphysis and from the
+neighbouring regions; thence it is directed towards the leg to be
+inserted into the superior part of the internal surface of the tibia,
+after being united to the tendons of the sartorius and semi-tendinosus.
+We find, accordingly, at this level, an arrangement which recalls the
+general appearance of what in man receives the name of _the goose's
+foot_ (_pes anserinus_).
+
+It is between this muscle and the sartorius, at the superior part of the
+internal surface of the thigh, in the region which recalls the triangle
+of Scarpa, that we are able, especially in the cat and the dog, to see
+the adductor muscles of the thigh. We also partly see there, in these
+animals, the vastus internus and the rectus of the triceps (see Fig.
+87). The gracilis is an adductor of the thigh.
+
+
+Muscles of the Leg
+
+We will divide the leg into three regions: anterior, external, and
+posterior. With regard to the internal region, there are no muscles
+which belong exclusively to it; for it is in great measure formed by the
+internal surface of the tibia, which, as in man, is subcutaneous.
+
+
+Muscles of the Anterior Region
+
+We first note that in the human species the tibialis anticus, extensor
+proprius pollicis, extensor longus digitorum and the peroneous tertius
+or anticus, form the subcutaneous layer of this region. We now proceed
+to study these muscles in quadrupeds.
+
+[Illustration: FIG. 83.--MYOLOGY OF THE HORSE: THE ANTERIOR TIBIAL
+MUSCLE (FLEXOR OF THE METATARSUS), LEFT LEG, ANTERIOR VIEW.
+
+1, Femoral trochlea; 2, tibia; 3, tendinous portion of the tibialis
+anticus; 4, cuboid branch of same; 5, 5, its metatarsal branch; 6,
+fleshy portion; 7, cuneiform branch of its tendon; 8, metatarsal branch
+of the same tendon; 9, extensor longus digitorum (anterior extensor of
+the phalanges turned outwards); 10, peroneus brevis (lateral extensor of
+the phalanges).]
+
+=Tibialis Anticus= (Fig. 83; Fig. 84, 6; Fig. 85, 4; Fig. 87, 10; Fig.
+88, 10, 11).--It is further named by veterinarians the _flexor of the
+metatarsus_.
+
+In the dog and the cat this muscle, which is rather large, arises from
+the external tuberosity of the tibia and from the crest of this bone. In
+its superior part it is flat, but lower down it is thick and produces a
+prominence in front of the tibia. Finally, it becomes tendinous, and
+passes towards the tarsus; thence it is directed towards the inner side
+of the metatarsus, and is inserted into the great-toe, this latter being
+sometimes well developed, but also often merely represented by a small
+bony nodule on which the muscle is then fixed.
+
+In the other animals with which we here occupy ourselves, the tibialis
+anticus presents a complexity which would be incomprehensible unless
+this muscle be first studied in the horse.
+
+In this latter the tibialis anticus consists of two distinct portions,
+placed one in front of the other: a fleshy portion, and a tendinous
+portion running parallel to it.
+
+The muscle is covered, except on its internal part and inferiorly, by a
+muscle with which we will occupy ourselves later on--that is, the common
+extensor of the toes.
+
+The tendinous portion of the tibialis anticus (Fig. 83), especially
+covered by the extensor of the toes, arises from the inferior extremity
+of the femur, from the fossa situated between the trochlea and the
+external condyle; thence it descends towards a groove which is hollowed
+out on the external tuberosity of the tibia, and is directed towards the
+tarsus, where it divides into two branches, which are inserted into the
+cuboid bone and the superior extremity of the principal metatarsal.
+These two parts form a ring through which the terminal tendon of the
+fleshy portion of the same muscle passes.
+
+This fleshy portion, situated behind the preceding, arises from the
+superior extremity of the tibia, on the borders of the groove in which
+the tendinous portion lies; thence it passes downwards for a short
+distance on the inner side of the common extensor of the toes, which
+covers it in the rest of its extent. It ends in a tendon which, after
+passing through the tendinous ring above noticed, divides into two
+branches. One of these branches is inserted into the anterior surface
+of the superior extremity of the principal metatarsal, the other into
+the second cuneiform bone.
+
+[Illustration: FIG. 84.--MYOLOGY OF THE DOG: LEFT HIND-LIMB, EXTERNAL
+ASPECT.
+
+1, Biceps cruris and fascia lata, divided in order to expose the upper
+part of the muscles of the leg; 2, inferior portion of the triceps
+cruris; 3, patella; 4, semi-tendinosus; 5, inferior extremity of the
+femur; 6, tibialis anticus (flexor of the metatarsus); 7, extensor
+longus digitorum (anterior extensor of the phalanges); 8, tibia; 9,
+peroneus longus; 10, peroneus brevis; 11, fifth metatarsal; 12,
+fasciculus detached from the peroneus brevis and passing towards the
+fifth toe; 13, external head of gastrocnemius; 14, tendo-Achillis; 15,
+calcaneum; 16, flexor digitorum sublimis; 17, 17, tendon of the flexor
+digitorum sublimis; 18, flexor longus pollicis (portion of the deep
+flexor of the toes); 19, dorsal muscle of the foot (short extensor of
+the toes).]
+
+In the ox the same two portions of the tibialis anticus exist, but with
+this capital difference--that the anterior portion is fleshy,
+superficial, and blended for a great part of its length with the common
+extensor of the toes.
+
+The portion which corresponds to that which is fleshy in the horse
+arises from the tibia; below, it ends on the inner surface of the
+superior extremity of the metatarsus and the cuneiform bones. That which
+represents the tendinous part, which is also fleshy, as we have just
+pointed out, arises above with the common extensor of the toes, from the
+femur, in the fossa situated between the trochlea and the external
+condyle; whilst below, after having given passage to the tendon of the
+preceding portion, as in the horse, it is inserted into the metatarsus
+and the cuneiform bones.
+
+In the pig, the tibialis anticus presents an arrangement nearly similar
+to that which we have just described.
+
+It seems to us of interest to add that it has been sought to ascertain
+to what muscle of the human leg the tendinous part of the tibialis of
+the horse corresponds--a part which has become fleshy in the pig and the
+ox.
+
+According to some authors, it represents the peroneus tertius; but that
+muscle is situated on the outer side of the common extensor of the toes;
+and here the portion with which it has been compared is placed on the
+inside. It has also been likened to a portion of the common extensor of
+the toes, but it does not pass to the latter. Lastly, it has been
+considered as being the homologue of the proper extensor of the
+great-toe; but why, then, in the ox, which has no great-toe, is it so
+highly developed? Nevertheless, its position and its relations
+sufficiently warrant this method of comprehending it. The tibialis
+anticus is a flexor of the foot. It is also able, in animals in which
+the tarsal articulations allow of the movement, to rotate the foot
+inwards.
+
+[Illustration: FIG. 85.--MYOLOGY OF THE OX: LEFT LEG, EXTERNAL ASPECT.
+
+1, Gluteus maximus and biceps cruris; 2, semi-tendinosus; 3, patella; 4,
+tibialis anticus (flexor of the metatarsus); 5, extensor longus
+digitorum (anterior extensor of the phalanges); 6, fasciculus of the
+extensor longus digitorum, which is considered as the representative of
+the tendinous portion of the tibialis anticus in the horse; 7, peroneus
+longus; 8, peroneus brevis (proper extensor of the external toe); 9,
+external head of gastrocnemius; 10, soleus; 11, tendo-Achillis; 12,
+calcaneum; 13, tendon of the extensor longus digitorum (superficial
+flexor of the phalanges); 14, flexor longus pollicis and tibialis
+posticus (deep flexor of the phalanges); 15, tendon of the superficial
+flexor of the toes; 16, tendon of the deep flexor of the toes; 17,
+suspensory ligament of the fetlock.]
+
+With regard to the tendinous part, called by veterinarians the _cord of
+the flexor of the metatarsus_, it serves, in the horse, to produce the
+flexion of the metatarsus when the knee is already flexed; it thus acts
+in a passive fashion, which is explained by its resistance and the
+position which it occupies in relation to these two articulations.
+
+=Extensor Proprius Pollicis.=--This muscle exists only in the dog and
+the cat, and there in a rudimentary condition.
+
+It is covered by the common extensor of the toes and the tibialis
+anticus, and passes, accompanied by the tendon of this latter muscle, to
+terminate on the second metatarsal, or the phalanx, which articulates
+with it. When the first toe exists in the dog, it is inserted into this
+by a very slender tendon.
+
+=Extensor Longus Digitorum= (Fig. 83, 9; Fig. 84, 7; Fig. 85, 5, 6; Fig.
+86, 4; Fig. 87, 12; Fig. 88, 7).--It is also called by veterinarians
+_the anterior extensor of the phalanges_.
+
+In the dog and the cat this muscle is to be seen in the space limited
+behind by the peroneus longus and in front by the tibialis anticus.
+Above it is covered by this latter. In the lower half of the leg, it is
+also in relation, on the inner side, with the tibialis anticus; but
+behind it is separated from the peroneus longus by the external surface
+of the shaft and inferior extremity of the tibia. This arrangement,
+besides, recalls that which is found in man, the peroneus longus of the
+latter diverging in the same way, at this level, from the common
+extensor, and leaving exposed the corresponding portion of the skeleton
+of the leg.
+
+This muscle, fusiform in shape, arises at its upper part from the
+external surface of the inferior extremity of the femur, then its tendon
+passes into a groove hollowed on the external tuberosity of the tibia.
+The fleshy body which succeeds is directed towards the tarsus, but
+before reaching it is replaced by a tendon. This tendon, at the level of
+the metatarsal bones, divides into four slips, which pass towards the
+toes, and are inserted into the second and third phalanges of the
+latter.
+
+In the horse it covers, to a great extent, the tibialis anticus, so that
+it is the latter which forms the large fusiform prominence especially
+noticeable in the middle region, to which the contour of the anterior
+surface of the leg is due.
+
+[Illustration: FIG. 86.--MYOLOGY OF THE HORSE: LEFT HIND-LIMB, EXTERNAL
+ASPECT.
+
+1, Semi-tendinosus; 2, biceps cruris; 3, patella; 4, extensor longus
+digitorum (anterior extensor of the phalanges); 5, reinforcing band
+arising from the ligament of the fetlock; 6, peroneus brevis (lateral
+extensor of the phalanges); 7, external head of gastrocnemius; 8,
+soleus; 9, tendo-Achillis; 10, calcaneum; 11, tendon of the superficial
+flexor of the toes (superficial flexor of the phalanges); 12, flexor
+longus pollicis and tibialis posticus (deep flexor of the phalanges);
+13, 13, tendon of the superficial flexor of the phalanges; 14, 14,
+tendon of the deep flexor of the phalanges; 15, suspensory ligament of
+the fetlock; 16, principal metatarsal: 17, external rudimentary
+metatarsal.]
+
+It arises above from the inferior extremity of the femur, from the fossa
+situated between the trochlea and the external condyle; therefore, it
+has a common origin with the tendinous portion of the tibialis anticus,
+or flexor of the metatarsus.
+
+The tendon, which at the level of the inferior part of the leg succeeds
+to the fleshy body, passes in front of the tarsus, the principal
+metatarsal, and receives the tendon of the peroneus brevis which we will
+describe later on. It then reaches the anterior surface of the fetlock.
+There it presents an arrangement analogous to that which we have pointed
+out in connection with the anterior extensor of the phalanges--a muscle
+which, in the fore-limbs, corresponds to the common extensor of the
+digits; that is to say, it is inserted, in form of an expansion, into
+the pyramidal prominence of the third phalanx, after having formed
+attachments to the first and second, and having received on each side a
+strengthening band from the suspensory ligament of the fetlock.
+
+In the ox the long extensor of the toes is united above, and for a great
+part of its length, with the portion of the tibialis anticus, which
+represents, albeit in the fleshy state, the tendinous cord of the latter
+in the horse.
+
+In common with this portion, it arises from the inferior extremity of
+the femur. Thence it passes towards the tarsus and divides into two
+fasciculi, internal and external, which are continued by tendons. These
+pass towards the phalanges, and, in case of the common extensor of the
+digits belonging to the fore-limbs, the internal is destined for the
+internal toe, and the external is common to the two toes.
+
+[Illustration: FIG. 87.--MYOLOGY OF THE DOG: LEFT HIND-LIMB, INTERNAL
+ASPECT.
+
+1, Semi-tendinosus; 2, semi-membranosus; 3, triceps cruris (vastus
+internus); 4, sartorius (patellar); 5, sartorius (tibial); 6, patella;
+7, first or middle adductor; 8, small and great adductor united; 9,
+gracilis; 10, tibialis anticus (flexor of the metatarsus); 11, tibia;
+12, tendon of extensor longus digitorum (anterior extensor of the
+phalanges): 13, gastrocnemius, inner head; 14, tendo-Achillis; 15,
+calcaneum; 16, popliteus; 17, superficial flexor of the toes; 18, flexor
+longus pollicis (portion of the deep flexor of the toes); 19, flexor
+longus digitorum (portion of the deep flexor of the toes); 20, tendon of
+the tibialis posticus.]
+
+[Illustration: FIG. 88.--MYOLOGY OF THE HORSE: LEFT HIND-LEG, INTERNAL
+ASPECT.
+
+1, Semi-tendinosus; 2, semi-membranosus; 3, triceps cruris (vastus
+internus); 4, patella; 5, sartorius; 6, gracilis; 7, extensor longus
+digitorum common extensor of the toes (anterior extensor of the
+phalanges); 8, tendon of the preceding muscle; 9, reinforcing band given
+off by the suspensory ligament of the fetlock; 10, tibialis anticus
+(flexor of the metatarsus), its tendinous portion; 11, tibialis anticus
+(flexor of the metatarsus), its fleshy portion; 12, cuneiform branch of
+the tendon of this fleshy portion; 13, internal head of gastrocnemius;
+14, popliteus; 15, tendon of the flexor brevis digitorum (superficial
+flexor of the phalanges); 16, flexor longus pollicis and tibialis
+posticus (deep flexor of the phalanges); 17, flexor longus digitorum
+(oblique flexor of the phalanges); 18, 18, tendon of the superficial
+flexor of the phalanges; 19, 19, tendon of the deep flexor of the
+phalanges; 20, suspensory ligament of the fetlock; 21, principal
+metatarsal; 22, internal rudimentary metatarsal.]
+
+In the pig the general arrangement of the muscle is similar, but the
+tendons end in a manner which is a little more complicated. Apart from
+the fasciculi which correspond to the tendinous portion of the tibialis
+anticus (fleshy here, as in the ox), the long extensor of the toes at
+the level of the tarsus divides into three tendons: the internal goes to
+the great internal toe; the middle bifurcates in the upper part of the
+digital portion of the foot, and each of its branches goes towards one
+of the great-toes; the external divides to pass towards each of the two
+small toes, and towards the great ones; but this latter disposition is
+not constant.
+
+By its contraction the muscle which we have just studied extends the
+phalanges and flexes the foot.
+
+=Peroneus Tertius.=--This muscle is not found in domestic quadrupeds.
+
+We should remember, nevertheless, that certain authors consider as
+representing it the tendinous portion of the anterior tibial of the
+horse, or the corresponding portion now fleshy, of the same muscle in
+the pig and the ox. It is by reason of this fact that it is called the
+third peroneal, notwithstanding that in the numerical order of the
+peroneals it is rather the first.
+
+But that which still further complicates this question of nomenclature
+is that some authors give this name of third to a peroneal which, in the
+carnivora, is situated more definitely in the group of external muscles
+(see below, =Short Lateral Peroneal=).
+
+
+Muscles of the External Region
+
+In man, two muscles constitute this region; they are the peroneus longus
+and peroneus brevis.
+
+=Peroneus Longus= (Fig. 84, 9; Fig. 85, 7).--This muscle does not exist
+in the domestic animals; only in the flesh-eaters, the pig and the ox
+excepted.
+
+It is in relation superiorly with the tibialis anticus, and inferiorly
+with the common extensor of the toes; in the ox, it is in contact with
+this latter muscle throughout its whole length.
+
+The peroneus longus arises from the external tuberosity of the tibia;
+towards the middle of the leg it is replaced by a tendon. This proceeds
+towards the tarsus, but previously it passes between the tibia and
+fibula. In the ox it is situated in front of the coronoid tarsal bone;
+we recollect that this bone is regarded as representing the inferior
+extremity of the fibula (see p. 97). Then it passes into a groove
+belonging to the cuboid bone or to the cuboido-scaphoid bone in the ox,
+traverses obliquely the posterior aspect of the tarsus, and is inserted
+into the rudimentary bone which represents the first toe; or, if this
+does not exist, into the innermost of the metatarsal bones.
+
+This muscle is an extensor of the foot. It also rotates it outwards in
+the animals in which the articulation permits this latter movement.
+
+=Peroneus Brevis= (Fig. 83, 8; Fig. 83, 10; Fig. 84, 10; Fig. 86,
+6).--In the dog and the cat, this muscle is covered in part by the
+peroneus longus, and arises from the inferior half of the tibia and the
+fibula; at the level of the tarsus it becomes tendinous, passes into a
+groove hollowed out on the external surface of the inferior extremity of
+the fibula, and terminates on the external aspect of the superior
+extremity of the fifth metatarsal. A little before this insertion it
+crosses the tendon of the long peroneal in passing to the outer side of
+the latter.
+
+To the short peroneal muscle is found annexed a very thin fasciculus
+which lies upon it. This fasciculus arises from beneath the head of the
+fibula, and is soon replaced by a thin tendon, which, accompanying that
+of the short peroneal, proceeds towards the foot, after having traversed
+the groove in the inferior extremity of the fibula; passes along by the
+fifth metatarsal (Fig. 84, 12); blends at the level of the first phalanx
+of the fifth toe with the corresponding tendon of the long extensor of
+the toes, and partakes of the insertions of this tendon.
+
+This fasciculus is designated by some authors under the name of the
+peroneal of the fifth toe, or the proper extensor of the same toe. But
+what makes still further complications is that other authors regard it
+as an anterior, or third, peroneal. Now, these names are those which
+other anatomists have applied to the fasciculus of the anterior tibial,
+which, in the pig and the ox, is fused in part with the long extensor of
+the toes. Hence there results a confusion which is truly regrettable.
+
+In brief, we can, without inconvenience, consider it as a fasciculus of
+the short peroneal muscle.
+
+We sometimes find in man, but abnormally, an arrangement which partly
+recalls that which we have just indicated. It consists in a duplication
+of the tendon of the short peroneal, one of the branches of which goes
+to the fifth metatarsal, and the other to the fifth toe; it is sometimes
+a single fasciculus which goes to the phalanges of this latter. We have
+met with examples of these anomalies.[31] In the pig, the short peroneal
+is situated on the same plane as the long. It consists of two clearly
+distinct fasciculi, which arise from the fibula. The tendon of the
+anterior fasciculus proceeds to the great external toe--that is to say,
+the fourth, of which it is the proper extensor. The posterior fasciculus
+terminates on the small external toe, the fifth, of which it is in like
+manner the extensor.
+
+  [31] Edouard Cuyer, 'Anomalies, Osseous and Muscular' (_Bulletins de
+       la Societe d'Anthropologie_, Paris, 1891).
+
+In the ox, the fleshy fibres of the short peroneal arise from a fibrous
+band which replaces the fibula, and from the external tuberosity of the
+tibia. Situated behind the long peroneal and on the same plane, it
+terminates in a tendon which appears at the level of the inferior part
+of the leg; it passes in front of the canon, and is inserted into the
+external toe, of which it is the proper extensor.
+
+In the horse, it is the sole representative of the peroneal muscles, and
+veterinary anatomists have given it the name of _the lateral extensor of
+the phalanges_.
+
+Its fleshy body arises above from the external lateral ligament of the
+knee-joint, and from the whole length of the fibula. In the middle third
+of the leg it is narrowed; lower down it is replaced by a tendon. This
+is lodged in a groove hollowed on the external surface of the inferior
+extremity of the tibia; then after passing along the external surface of
+the tarsus, it is directed forward, and proceeds to blend towards the
+middle of the canon-bone with the tendon of the long extensor of the
+toes, or anterior extensor of the phalanges, of which it shares the
+insertions. It extends the phalanges into which it is inserted. It also
+flexes the foot.
+
+
+Muscles of the Posterior Region
+
+It will not be unprofitable to recall to mind that, in man, the muscles
+of this region are arranged in two layers: a superficial layer
+consisting of the gastrocnemius and soleus, to which is added a muscle
+of little importance, the plantaris, and a deep layer formed by four
+muscles--the popliteus, flexor longus digitorum, tibialis posticus, and
+flexor longus pollicis.
+
+The gastrocnemius and soleus, independent in their upper portion, unite
+below in a common tendon; they thus form also a triceps muscle, which we
+designate under the name of the triceps of the leg, or triceps suralis,
+because it forms the elevation of the calf of the leg (from _sura_,
+calf).
+
+=Gastrocnemius= (Fig. 83, 9, 11; Fig. 84, 13, 14; Fig. 86, 7, 9; Fig.
+88, 13).--The external and internal heads of the gastrocnemius, distinct
+from one another only in their upper portion, arise from the shaft of
+the femur, above the condyles, on the borders of the popliteal surface,
+to a relatively considerable extent in the great quadrupeds.
+
+At this level they are situated in the popliteal region--that is to say,
+in the space limited externally by the biceps, and internally by the
+semi-tendinosus. But as they descend to a rather low level on the leg in
+quadrupeds, and especially in carnivora, they do not, properly speaking,
+determine a projection of the calf of the leg. However, they pass from
+this region but to be soon continued by a tendon--the tendo-Achillis,
+which is inserted into the calcaneum.
+
+Now, the region of the tarsus is called by veterinarians _the ham_, the
+posterior surface of which is angular, because of the oblique direction
+of the leg with regard to the vertical direction of the metatarsus and
+the presence of the calcaneum; the prominence which this surface
+presents has received the name of _the point of the ham_, and the tendon
+which ends there that of _the cord of the ham_.
+
+But the tendo-Achillis does not alone form this cord. Indeed, as we will
+soon see, the tendon of the superficial flexor of the toes takes part in
+its formation.
+
+We may add, with regard to the tendo-Achillis, that it is more clearly
+perceived as an external feature, because the skin sinks in front of it,
+as it does in man, over the lateral parts of the region which it
+occupies.
+
+The gastrocnemius, when it contracts, extends the foot on the leg.
+
+It serves to maintain the tibio-tarsal angle in the standing position,
+and during walking, to determine the steadying of the hind-limbs, which
+then, after the fashion of a spring, project the body forward.
+
+By an analogous movement they take part in the posterior projection of
+the hind-limbs in the act of kicking; but they are not the only ones to
+act in this case, the muscles of the buttock and thigh also being
+brought into play.
+
+=Soleus= (Fig. 83, 10; Fig. 86, 8).--This muscle, much less developed in
+quadrupeds than in man, does not exist in the dog.
+
+With regard to the soleus in the pig, Professor Lesbre says: 'Meckel
+denied its existence; we, however, believe that it is united to the
+external head of the gastrocnemius, its origin being transferred to the
+femur.'[32]
+
+  [32] F. X. Lesbre, 'Essai de Myologie comparee de l'homme et des
+       mammiferes domestiques en vue d'etablir une nomenclature unique
+       et rationelle,' Lyon, 1897, p. 169.
+
+But in animals in which it exists, this muscle, of but little
+importance, occupies the outer side of the leg. It arises above from the
+external tuberosity of the tibia, and terminates below in a tendon which
+is united with that of the gastrocnemius.
+
+The soleus has the same action as these latter.
+
+=Plantaris.=--In quadrupeds this muscle is blended with the superficial
+flexor of the toes, which we will study afterwards.
+
+=Popliteus= (Fig. 87, 16; Fig. 88, 14).--In man, this muscle, which
+occupies the posterior surface of the tibia, above the oblique line, is
+completely covered by the gastrocnemius.
+
+In quadrupeds, where it is more voluminous, it projects internally
+beyond the gastrocnemius, so that it is seen in the internal and
+superior part of the region of the superficial layer of muscles,
+immediately behind the internal surface of the tibia, which, as we know,
+is subcutaneous.
+
+The popliteus arises from the external surface of the external condyle
+of the femur. Thence its fibres which diverge pass to be inserted into
+the superior part of the posterior surface and of the internal border of
+the tibia. It is in this latter region that it projects beyond the
+gastrocnemius, but we may add that there it is more or less covered by
+the semi-tendinosus.
+
+It flexes the leg, and rotates it forwards.
+
+=Superficial Flexor of the Toes= (Fig. 83, 13, 15; Fig. 84, 17; Fig. 86,
+11, 13, 13; Fig. 87, 17; Fig. 88, 15, 18, 18).--In man, the homologue of
+this muscle is found in the sole of the foot. It is called _the short
+flexor of the toes_. It arises from the calcaneum, and passes to the
+four outer toes. In quadrupeds, it rises as high as the back of the
+knee, and is found blended with the plantaris.
+
+Further designated by the name of _the superficial flexor of the
+phalanges_, covered in part by the gastrocnemius, with which it is in
+relation for a great part of the course which it traverses, this muscle
+arises from the posterior surface of the femur, on the external branch
+of the inferior bifurcation of the linea aspera. In the horse, this
+origin takes place in a depression situated above the external condyle,
+in the supracondyloid fossa. Then it accompanies the gastrocnemius, and
+becomes tendinous where the tendo-Achillis commences. It then winds
+round the latter in placing itself on its inner side, then on its
+posterior surface, and reaches the calcaneum. It accordingly
+contributes, as we have already pointed out, to form the cord of the
+ham. After having become expanded, and having covered as with a sort of
+fibrous cap the bone of the heel, it descends behind the metatarsus, and
+presents there an arrangement analogous to that which we pointed out in
+connection with the superficial flexor of the digits--that is, it
+contributes to form the _tendon_. This prominence, in the form of a
+cord, we see behind the canon-bone in solipeds and ruminants. It
+finally terminates in the same way as the muscle with which we have
+compared it (see p. 197).
+
+In the horse, its fleshy body is but slightly developed, so that its
+tendon alone is specially visible in the superficial muscular layer, but
+in the dog and the cat it is large. Hence it results that its fleshy
+body appears on each side of the inferior half of the gastrocnemius, and
+produces an elevation which recalls that which the soleus produces on
+each side of the same muscles in the human species.
+
+The muscles which follow form, with the popliteus, which we have already
+studied, the deep layer of the posterior region of the leg.
+
+=Flexor Longus Digitorum= (Fig. 87, 19; Fig. 88, 17).--This muscle, in
+man, is the only common flexor of the toes belonging to the muscles of
+the leg.
+
+In comparison with the preceding muscle, it is a deep flexor.
+Veterinarians have given it the name of _the oblique flexor of the
+phalanges_.
+
+Visible on the internal aspect of the superficial layer of the muscles
+of the leg, this muscle arises above from the posterior surface of the
+external tuberosity of the tibia, becomes tendinous, passes towards the
+metatarsus, and blends with the tendons of the posterior tibial and the
+long proper flexor of the great-toe. In the dog and the cat it is
+blended with this latter only.
+
+=Tibialis Posticus= (Fig. 85, 14; Fig. 86, 12; Fig. 87, 20; Fig. 88,
+16).--This muscle arises from the external tuberosity of the tibia, and
+from the head of the fibula. Thence it passes to the tarsus, and
+terminates in different fashion in carnivora and other quadrupeds.
+
+In the dog and the cat, it is inserted into the ligamentous apparatus of
+the tarsus, or into the base of the second metatarsal.
+
+In the other quadrupeds with which we are here occupied it is blended
+with the long proper flexor of the great-toe.
+
+It is accordingly in the carnivora that the mode of termination of the
+tibialis posticus most nearly resembles that of this same muscle in the
+human species. From this independence there results a special action.
+
+It is an adductor and internal rotator of the foot.
+
+=Flexor Longus Pollicis= (Fig. 84, 18; Fig. 85, 14; Fig. 86, 12; Fig.
+87, 18; Fig. 88, 16).--This muscle, as that in man, is the most external
+of the deep layer of the leg. It is on the external aspect of the latter
+we perceive it, between the peroneals and the gastrocnemius or
+tendo-Achillis.
+
+It arises from the fibula and tibia, and is thence directed towards the
+tarsus. It unites with the long common flexor of the toes to form with
+it _the deep flexor of the phalanges_, of which it is the principal
+fasciculus. We may add that in the dog and the cat the posterior tibial
+remains independent of this latter, but that in the pig, ox, and horse
+the posterior tibial is united to the preceding to form with them the
+deep flexor muscle.
+
+Thus constituted, the deep flexor goes towards the phalanges, where it
+terminates as the deep flexor of the digits of the fore-limbs (see p.
+197). In animals possessed of a canon it contributes to form the
+_tendon_ (Fig. 85, 16; Fig. 86, 14, 14; Fig. 88, 19, 19).
+
+
+Muscles of the Foot
+
+We must remember that on the dorsal surface of the foot in man we find
+but a single muscle--the dorsalis pedis. The remaining subcutaneous
+structures of this region consist of the tendons of the anterior muscles
+of the leg which occupy this dorsal aspect.
+
+=Dorsalis Pedis= (Fig. 84, 19).--Also called the extensor brevis
+digitorum, the dorsalis pedis muscle is found in all domestic
+quadrupeds; but its development is so much the less as the number of
+digits is more reduced.
+
+In the dog and the cat it arises from the calcaneum, and is inserted
+into the three internal toes (the first toe excepted) by uniting with
+the corresponding tendons of the common extensor.
+
+In the pig its disposition is analogous.
+
+As for the dorsalis pedis of the ox and the horse, it is extremely
+rudimentary, and occupies the superior part of the canon. It is a small,
+fleshy body, situated on the anterior surface of the metatarsus, which
+arises from the calcaneum, whence it passes to unite at its inferior
+extremity with the tendon of the extensor of the phalanges.
+
+As regards the muscles of the sole of the foot, we think it unnecessary
+to occupy ourselves at any length with them because of their slight
+importance with regard to external form.
+
+We will only recall that in the median portion of this plantar surface
+we find in man the short flexor of the toes, which in quadrupeds arises
+higher up, from the posterior surface of the femur; that it belongs to
+the muscles of the leg; and that it forms the superficial flexor of the
+toes, which we have already studied.
+
+We may further add that the suspensory ligament of the fetlock in
+ruminants and solipeds represents, as in the fore-limbs, the
+interosseous muscles.
+
+
+MUSCLES OF THE HEAD
+
+We will divide these muscles into two categories: masticatory and
+cutaneous.
+
+
+Masticatory Muscles
+
+The muscles of this group which specially interest us are the masseter
+and the temporal. As regards the pterygoids, since they are situated
+within the borders of the inferior maxillary bone, and consequently do
+not reach the surface, we shall not require to occupy ourselves with
+them here.
+
+=Masseter= (Fig. 89, 2; Fig. 90, 1; Figs. 91, 92).--For those who have
+studied the masseter of man, it is not difficult to recognise that of
+quadrupeds. Nevertheless, the particular aspect which it presents in
+different species gives to its study a certain interest.
+
+Arising from the zygomatic arch, and passing downwards and backwards, it
+is inserted into the external surface of the ramus of the mandible and
+into its angle.
+
+Its posterior border is in relation with the parotid gland (Fig. 90, 14;
+Figs. 91, 92), this gland being situated between the corresponding
+border of the lower jaw bone and the transverse process of the atlas.
+Such are the general characters; the following are the particular ones:
+
+In the carnivora it is thick and convex. In the horse it is flat, but
+more expanded; it forms the _flat of the cheek_. In the ox it is flat,
+as in the latter; but, while being less thick, it is more prolonged in
+the vertical direction.
+
+The form of the osseous parts which give it origin is, besides, in
+relation with these differences, and explains the peculiar characters
+which the masseter presents.
+
+[Illustration: FIG. 89.--MYOLOGY OF THE DOG: MASTICATORY MUSCLES (A
+DEEPER DISSECTION THAN THAT SHOWN IN FIG. 90).
+
+1, Zygomatic arch; 2, masseter; 3, temporal exposed by the suppression
+of the auricular and occipital muscles and the pinna of the ear; 4,
+auditory canal; 5, inferior maxillary bone; 6, digastric.]
+
+Indeed, in the dog and the cat the zygomatic arch, strongly convex,
+springs up in a marked manner from the plane of the lateral aspects of
+the skull.
+
+In the horse the same arch, less prominent externally, is prolonged by a
+rectilinear crest on the superior maxillary bone, where it is continued
+in forming the zygomatic or maxillary spine.
+
+In the ox the same crest ascends a good way towards the inferior margin
+of the orbit in a curved direction with the concavity inferior, to
+redescend afterwards on the external surface of the superior maxilla.
+
+The masseter is an elevator of the lower jaw. It acts, above all, as in
+the human species, in the process of mastication.
+
+=Temporal Muscle= (Fig. 89, 3).--The development of the temporal is in
+proportion to the energy of the movements of elevation which the lower
+jaw has to execute.
+
+It arises from the temporal fossa, and is inserted into the coronoid
+process of the inferior maxilla.
+
+Its development, enormous in the carnivora, is such that the muscle
+projects beyond its fossa. It is less voluminous in the horse, and still
+less so in the ox. In the latter, indeed, the temporal fossa, although
+deep, is of small extent (see Fig. 62, p. 119); the frontal bone being
+large, it is found to be thrown back on the lateral walls of the
+cranium, below the osseous processes which support the horns and
+overhang the fossa in question, as well as the muscle which it contains.
+
+It is covered by the auricular muscles, and by the base of the pinna of
+the ear.
+
+Like the masseter, the temporal is an elevator of the lower jaw.
+
+
+Cutaneous Muscles of the Head
+
+=Occipito-Frontalis.=--The epicranial aponeurosis is extremely thin. In
+the dog the occipital muscle occupies the superior part of the head; it
+overlies the temporal muscle.
+
+With regard to the frontal muscle, which is of great extent in the ox
+(Fig. 91, F), it is represented in the horse and the carnivora by a
+small fleshy fasciculus only, the _fronto-palpebral muscle_, similar to
+the superciliary muscle. This, occupying the superior and internal part
+of the border of the orbit, ends by blending its fibres with those of
+the orbicular muscle of the eyelids at the region of the eyebrow.
+
+=Orbicularis Palpebrarum= (Fig. 90, 2; Figs. 91, 92).--This annular
+muscle surrounds the palpebral orifice, and takes its origin on the
+internal part of the orbital region. In the horse it arises, by a small
+tendon, from a tubercle which occupies the external surface of the os
+unguis, or lachrymal bone.
+
+This muscle determines the narrowing and closure of the palpebral
+orifice.
+
+=Pyramidalis Nasi.=--The pyramidal muscle is not found in the domestic
+animals. It appears to be blended with the internal elevator of the
+upper lip and wing of the nose; this is easy of comprehension if we bear
+in mind the relative position of these two muscles in the human species.
+
+[Illustration: FIG. 90.--MYOLOGY OF THE DOG: MUSCLES OF THE HEAD.
+
+1, Masseter; 2, orbicularis palpebrarum; 3, zygomaticus major; 4,
+lachrymal (this muscle is sometimes described under the name of the
+small zygomatic); 5, levator labii superioris proprius; 6, levator
+labii superioris alaeque nasi; 7, caninus; 9, buccinator; 11,
+zygomatico-auricularis; 12, external temporo-auricularis; 14, parotid
+gland; 15, parotido-auricularis; 16, inferior maxillary bone; 17,
+digastric.]
+
+=Corrugator Supercilii.=--This muscle is represented by the
+fronto-palpebral muscle noticed above, which is by some regarded as a
+vestige of the frontal.
+
+=Zygomaticus Major= (Fig. 90, 3; Figs. 91, 92).--This is the
+_zygomatic-labial_ of veterinarians. This muscle is of an elongated
+form, and has a ribbon-like aspect.
+
+In the dog and the cat it arises from the base of the pinna of
+the ear, from the portion of this base which bears the name of
+scutiform cartilage. (With regard to this cartilage, see p. 242,
+=Zygomatico-auricularis=.) From this it is directed downwards and
+forwards, to terminate, after having crossed the masseter, on the deep
+surface of the skin of the corresponding labial commissure.
+
+This mode of termination is the same in the ox and the horse; but where
+the muscle differs is at the level of its upper extremity. There it
+ascends less than in the carnivora. In the ox it arises from the
+zygomatic arch in the neighbourhood of the temporo-maxillary
+articulation; in the pig and the horse its origin is still lower, on the
+surface of the masseter, close to the maxillary spine.
+
+When it contracts, it draws upwards the labial commissure.
+
+Now, in man, we remember, it is the great zygomatic that, by an action
+of the same kind, determines the essential characters of the expression
+of laughing.
+
+There is, accordingly, a connection to be established between those
+displacements which are similar and the analogy of facial expression
+which necessarily results from them.[33]
+
+  [33] Edouard Cuyer, 'The Mimic,' Paris, 1802.
+
+=Zygomaticus Minor= (Fig. 90, 4; Figs. 91, 92).--The existence of this
+muscle has not been clearly demonstrated. Nevertheless, Straus-Durckheim
+noted its presence in the horse, and described it as 'a muscle arising
+by two heads, of which one, the superior, arises from the malar bone
+below the orbit, and passes downwards and forwards over the
+fibro-adipose layer which supports the moustache. The second, the
+inferior, arises from the alveolar border in front of the second molar
+tooth, and passes forward to be inserted into the same fibro-adipose
+layer.'[34]
+
+  [34] H. Straus-Durckheim, 'Anatomie descriptive et comparative du
+       chat,' Paris, 1845, t. ii., p. 210.
+
+In connection with other quadrupeds, it is described by certain authors
+as a very thin muscle, arising below the cavity of the orbit, where it
+is blended with the fibres of the internal elevator of the upper lip and
+the ala of the nose; thence it proceeds to terminate below by uniting
+with the subcutaneous muscle. But this muscle is regarded by other
+authors as the lachrymal muscle, which does not exist in this state in
+man, but of which the development is particularly remarkable, as to
+extent, in the ox, in which it descends as far as the buccinator.
+
+According to other authors, some of the fibres of this muscle constitute
+the small zygomatic.
+
+[Illustration: FIG. 91.--MYOLOGY OF THE OX: MUSCLES OF THE HEAD.
+
+1, Masseter; 2, orbicularis palpebrarum; F, frontalis; 3, zygomaticus
+major; 4, lachrymal (this muscle is sometimes described under the
+name of small zygomatic); 5, levator labii superioris proprius; 6,
+levator labii superioris alaeque nasi; 7, levator anguli oris or
+caninus; 8, orbicularis oris; 9, buccinator; 10, maxillo-labial; 11,
+zygomatico-auricularis; 12, external temporo-auricularis; 14, parotid
+gland; 15, parotido-auricularis; 16, inferior maxillary bone.]
+
+=Levator Labii Superioris Proprius= (Fig. 90, 5; Figs. 91, 92).--Also
+named by veterinarians the _supramaxillo-labial_, or again, the _proper
+elevator of the upper lip_, this muscle arises from the external surface
+of the superior maxillary bone, passes under the superficial elevator,
+which we shall study in the succeeding paragraph, and goes to be
+inserted into the thickness of the lip, to which its name indicates that
+it belongs.
+
+The peculiarities of this muscle in different animals are the following:
+
+In the dog and the cat it arises behind the infra-orbital foramen.
+
+In the pig it arises from a depression below the orbital cavity, and its
+fleshy body is terminated in front by a strong tendon in the upper part
+of the snout, in which it divides into fasciculi.
+
+In the ox it arises from the maxillary spine.
+
+In the horse it arises below the orbital cavity; then, after having
+crossed the superficial elevator, it ends in a tendinous expansion,
+situated in the median line between the nasal fossae. This expansion
+divides into fasciculi, which end in the thickness of the upper lip.
+
+By the contraction of this muscle, the lip is raised, on one side only,
+if a single muscle contracts, or in its whole extent, if the two muscles
+act simultaneously.
+
+=Internal Elevator (or Superficial) of the Upper Lip and the Wing of the
+Nose= (_levator labii superioris alaeque nasi_) (Fig. 90, 6; Figs. 91,
+92).--This is the muscle veterinarians designate _the supranaso-labial_.
+
+Arising from the frontal and nasal bones, it thence passes towards the
+upper lip, where it is inserted as well as into the wing of the nose.
+
+In the ox it is united above with the frontal muscle, and below is
+divided into two fasciculi, between which pass the elevator described
+above and the canine muscle.
+
+In the horse it is also divided into two fasciculi; but the arrangement
+is the opposite as regards, their relations with neighbouring muscles,
+in this animal and in the preceding.
+
+In the ox the external fasciculus is covered by the external elevator
+and the canine, which pass under the internal fasciculus; in the horse
+the deep elevator passes under the two fasciculi, and the canine passes
+under the external bundle, and afterwards covers the internal.
+
+In the pig, the internal elevator is wanting.
+
+As its name indicates, it raises the upper lip and the wing of the
+nose.
+
+=Transversus Nasi.=--In the horse this muscle, which is very thin, is
+situated on the dorsum of the nose, and proceeds to be inserted into the
+cartilaginous skeleton of the nostrils. In the pig, it occupies an
+analogous situation. It does not exist in the ox or in carnivora. The
+transversus nasi is a dilator of the nostrils.
+
+[Illustration: FIG. 92.--MYOLOGY OF THE HORSE: MUSCLES OF THE HEAD.
+
+1, Masseter; 2, orbicularis palpebrarum; 3, zygomaticus major; 4,
+lachrymal (this muscle is sometimes described under the name of the
+small zygomatic); 5, external elevator (or deep) of the upper lip and
+ala of the nose; 6, internal elevator (or superficial) of the upper lip
+and of the ala of the nose; 7, levator anguli oris or caninus; 8,
+orbicularis oris; 9, buccinator; 10, maxillo-labialis; 11,
+zygomatico-auricularis; 12, temporo-auricularis externus; 13,
+cervico-auricularis; 14, parotid gland; 15, parotido-auricularis; 16,
+inferior maxillary bone.]
+
+=Caninus= (Fig. 90; Figs. 7, 91, 92).--This is the muscle called by
+veterinarians _the great supramaxillo-nasal_.
+
+In the dog and the cat it is situated below the inferior border of the
+external elevator of the upper lip, of which it follows the direction.
+It arises, as does this latter, from the external surface of the
+maxilla, and goes also to terminate in the upper lip by blending with
+the internal elevator of this lip and of the alae of the nose. It raises
+the upper lip.
+
+In the ox, it arises from the maxillary spine, and then divides into
+three parts; the superior passes under the internal portion of the
+internal elevator of the upper lip and the alae of the nose, and goes
+into the nostril; whilst the two others, situated lower down, terminate
+in the upper lip.
+
+In the pig, it is formed of two superimposed fasciculi, which arise from
+the spine of the maxilla and the impressions in front of it. These two
+fasciculi terminate in the snout, which they move laterally.
+
+In the horse, it is situated at a certain distance from the external
+elevator; in the preceding animals it is in contact with the latter.
+Arising behind from the external surface of the maxilla, in front of the
+maxillary spine, it is directed towards the anterior part of the face,
+passes under the external portion of the internal elevator (it is the
+opposite of this in the ox), and proceeds, on expanding, to terminate in
+the skin of the nostril. By its contraction it dilates the latter.
+
+=Orbicularis Oris= (Fig. 91, 8; Fig. 92).--This muscle, very fleshy in
+the solipeds and the ruminants, is arranged as a ring round the buccal
+orifice, in the thickness of the lips, where it is blended with the
+other muscles of this region.
+
+Having for its function the narrowing of the orifice it surrounds, it
+acts during suction and in the prehension of food.
+
+=Triangularis Oris.=--This muscle does not exist in domestic quadrupeds.
+
+=Quadratus Menti.=--In the pig and the carnivora, it arises from the
+anterior part of the body of the inferior maxillary bone, and passes at
+the other end to terminate in the corresponding portion of the lower
+lip, which it depresses by its contraction.
+
+In the ox and the horse this muscle does not exist; it is replaced for
+the depression of the lower lip, which it affects in other animals, by
+supplemental fibres of the buccinator.
+
+=The Prominence of the Chin.=--Below the lower lip in the horse is
+situated the so-called _prominence of the chin_, limited posteriorly by
+the _beard_, a depressed region which gives point to the curb of the
+bridle.
+
+The prominence, which also exists in the ox, is a fibro-muscular pad
+which blends with the orbicular muscle of the lips, and receives on its
+superior aspect the insertion of the two muscles (_levator menti_) by
+which it is suspended. These arise, above, on each side of the symphysis
+of the inferior maxillary bone. They raise the lower lip with force, and
+they are the agents which, as we can sometimes observe in the horse,
+make it click against the upper lip, suddenly projecting it upwards.
+This action sometimes becomes a habit, and its continuance constitutes a
+vice.
+
+A corresponding structure is found in the pig and in the carnivora, but
+in them it does not produce an external prominence such as we have
+described.
+
+=Buccinator= (Fig. 90, 9; Figs. 91, 92).--Further designated by the name
+of _alveolo-labial_, this muscle is situated on the lateral portions of
+the face, in the thickness of the cheeks. It consists of two layers, one
+superficial and the other deep.
+
+The deep portion arises from the portion of the alveolar border of the
+superior maxillary bone which corresponds to the molar teeth, and from
+the anterior border of the ramus of the mandible. Thence it is directed
+forwards, passes under the superficial layer, and blends with the fibres
+of the orbicular muscle of the lips. To this part of the buccinator some
+authors give the name of molar muscle.
+
+The superficial portion is formed by fibres which pass from the alveolar
+border of the superior maxillary bone to the corresponding border of the
+opposite bone. It is very highly developed in the herbivora.
+
+This muscle acts especially during mastication; it serves to press back
+again under the molar teeth the portions of food which fall outside the
+dental arch.
+
+In the pig, the ox, and the horse, a muscle which is considered as
+supplemental to the buccinator is placed along the inferior border of
+the latter.
+
+This muscle, which we describe separately under the names of
+_maxillo-labialis_ (Fig. 91, 10; Fig. 92) and _depressor of the lower
+lip_, is clearly distinct from the buccinator, especially in the horse.
+It arises, behind, with the deep layer of the muscle to which it is
+annexed, from the anterior border of the ramus of the lower jaw; in
+front it terminates in the thickness of the lower lip.
+
+In the ox, it is more intimately united with the buccinator.
+
+It depresses the lip to which it is attached, and displaces it laterally
+when it acts on one side only.
+
+In the human species, the pinna of the ear being generally immobile, the
+muscles which belong to it are, very naturally, considerably atrophied.
+Accordingly, the auricular muscles, anterior, superior, and posterior,
+are reduced to pale and thin fleshy lamellae, whose action is revealed in
+certain individuals, only in a way which may be said to be abnormal.
+
+It is not the same in quadrupeds. The pinna of the ear is extremely
+mobile, and its displacements have a real value from the point of view
+of physiognomical expression. It is therefore necessary to review the
+muscles which move this pinna without giving them, at the same time,
+more importance than they merit, since in themselves they do not
+determine the formation of surface reliefs, which are sufficiently
+apparent.
+
+Notwithstanding that for certain of these muscles it is possible to
+trace their analogy with those of the auricular region of man, it is
+very difficult, because of their complexity, to trace this analogy for
+all. This is why we shall not be able here, as we have done for the
+other muscles of the subcutaneous layer, to give at the head of each
+paragraph the name of a human muscle, and then to group in the same
+paragraph the muscles which correspond to it in different quadrupeds.
+Therefore the nomenclature and the divisions adopted for these latter
+must serve us as a base or starting-point.
+
+Because the pinna of the horse's ear is so very mobile, we will first
+begin with a study of its auricular muscles.
+
+=Zygomatico-auricularis= (Fig. 92, 11).--This muscle, which is formed of
+two small bands of fleshy fibres, arises from the zygomatic arch in
+blending with the orbicular muscle of the eyelids; thence it is
+directed towards the base of the pinna of the ear, and is inserted into
+this base, and also into the cartilaginous plate situated in front of
+and internal to this, and resting on the surface of the temporal muscle;
+this is the scutiform cartilage.
+
+The zygomatico-auricularis, which we look on as the homologue of the
+anterior auricular of man, draws the pinna of the ear forwards.
+
+=Temporo-auricularis Externus= (Fig. 92, 12).--This, which is thin and
+very broad, covers the temporal muscle.
+
+It arises from the whole extent of the parietal crest, blending in this
+plane, in its posterior half, with the muscle of the opposite side.
+Thence it is directed outwards towards the pinna of the ear, and is
+inserted into the internal border of the scutiform cartilage and on the
+inner side of the concha--that is to say, of the conchinian
+cartilage--which forms the principal part of the pinna. We are
+supposing, in the description of the muscles which move it, that this
+pinna has its opening directed outwards.
+
+The external temporo-auricular, which recalls, from its situation, the
+superior auricular of man, is an adductor of the ear; besides, it causes
+it to describe a movement of rotation from without inwards, so as to
+direct its opening forwards.
+
+=Scuto-auricularis Externus.=--This muscle may be considered as
+supplementary to the external temporo-auricular; the concha fasciculus
+of this latter partly covers it.
+
+Extending from the scutiform cartilage to the inner side of the concha,
+it contributes to the movement of rotation by which the opening of the
+pinna of the ear is directed forwards.
+
+=Cervico-auricular Muscles= (Fig. 92, 13).--These muscles, three in
+number, are situated behind the pinna of the ear; they are called, from
+their mode of superposition, the superficial, middle, and deep.
+
+These arise, all three, from the superior cervical ligament, and pass
+from there towards the cartilage of the concha. They recall, as regards
+situation, the posterior auricular muscle of man.
+
+=Superficial Cervico-auricular= (_Cervico-auricularis
+superioris_).--This muscle, inserted into the posterior surface of the
+concha, draws this cartilage backwards and downwards.
+
+=Middle Cervico-auricular= (_Cervico-auricularis medius_).--Situated
+between the two other muscles of the same group, it proceeds, after
+having covered the superior extremity of the parotid gland, to be
+inserted into the external part of the base of the concha. It determines
+the rotation of this concha in such a way as to direct the opening of
+the ear backwards.
+
+=Deep Cervico-auricular= (_Cervico-auricularis inferioris_).--Covered by
+the preceding muscle and the superior portion of the parotid, it is
+inserted into the base of the pinna of the ear, and has the same action
+as the middle cervico-auricular.
+
+=Parotido-auricularis= (Fig. 92, 15).--This is a long and thin fleshy
+band which arises from the external surface of the parotid gland, and
+tapering as it passes upwards towards the pinna of the ear, is inserted
+into the external surface of the base of the concha, below the inferior
+part of the angle of reunion of the two borders which limit its opening.
+
+It inclines the pinna outwards; it is, accordingly, an abductor of the
+pinna.
+
+=Temporo-auricularis Internus.=--This muscle is covered by the external
+temporo-auricular and the superior cervico-auricular. It arises from the
+parietal crest, and is inserted into the internal surface of the concha.
+It is an adductor of the pinna of the ear.
+
+There are, finally, an internal scuto-auricular muscle and a
+tympano-auricular; but they do not present any interest for us; we can
+simply confine ourselves to making mention of them.
+
+In the ox, because of the situation of the temporal fossa and the fact
+that the external temporo-auricular muscle is applied, as in the horse,
+over the muscle which this fossa contains, this temporo-auricular muscle
+does not reach the middle line (Fig. 91, 12).
+
+But in the cat and the dog this muscle covers all the upper part of the
+head (Fig. 90, 12). It is divided into two parts: the interscutellar and
+the fronto-scutellar.
+
+The interscutellar is a single muscle, thin and broad, covering the
+temporal muscle and a portion of the occipital, extending from the
+scutiform cartilage of the pinna of one side to the same cartilage of
+the pinna belonging to the side opposite. It approximates the two pinnae
+to one another by bringing them each into the position of adduction.
+
+The fronto-scutellar arises from the orbital process of the frontal
+bone, and from the orbital ligament, which at this level completes the
+interrupted osseous boundary of the orbital cavity. Thence it is
+directed, widening as it proceeds, towards the scutiform cartilage, and
+is there inserted by blending with the corresponding part of the great
+zygomatic. Its action is analogous to that of the preceding muscle; but,
+further, it directs the opening of the pinna forwards.
+
+These are the muscles which act, for example, when the dog, having his
+attention strongly attracted by any cause, pricks up his ears and turns
+the openings forward, in order the better to understand every sound
+which proceeds, or may possibly proceed, from that which he observes.
+From this, which may be extremely well seen in some individuals, results
+the appearance of vertical wrinkles of the skin in the interval between
+the pinnae of the ears, these being caused by the folding of the
+integument, whilst the pinnae approach one another. These movements, with
+which are associated fixation of look and a widening of the palpebral
+fissure, produce a peculiarly expressive look; this is why they merit
+our attention.
+
+=Zygomatico-auricularis= (Fig. 90, 11).--Arises from the internal
+surface of the great zygomatic, passes towards the pinna of the ear, and
+goes to be inserted into the external part of the base of the pinna,
+below its opening, to a prominence which corresponds to the antitragus
+of the human ear. It is to this antitragus, but proceeding from another
+direction, that the parotido-auricular muscle is inserted (Fig. 90, 15).
+
+With regard to the cervico-auriculars, they are all three present. The
+superior, or superficial, situated behind the interscutellar portion of
+the external temporo-auricular, has its origin on the median line of the
+neck; thence it passes towards the pinna of the ear, blending its fibres
+with those of the interscutellar muscle, and is inserted into the
+scutiform cartilage and the internal surface of the pinna.
+
+Such are the principal muscles of the ear in the carnivora; it would
+seem to us superfluous to dwell on the others of this region, so that we
+will here conclude the study of the muscles in general, and that of the
+myology of the head in particular.
+
+
+
+
+CHAPTER III
+
+EPIDERMIC PRODUCTS OF THE TERMINAL EXTREMITIES OF THE FORE AND HIND
+LIMBS
+
+
+We will first recall to mind that among the quadrupeds some are found of
+which the fingers and toes have their third phalanges terminated by
+claws--these are the unguiculates; and that in others the terminal
+extremity of each limb is completely encased in a horny envelope, the
+hoof--these are the ungulates.
+
+In the first group, the claws remind us to a certain extent of the
+arrangement of the nails in man; the inferior aspect of the paws is
+covered by an epidermic layer, thick and protective, which may be
+likened to the skin, correspondingly thick, which covers in the greater
+part of its extent the plantar surface of the foot in the human species.
+
+In the second group, the surface by which the third phalanx rests on the
+ground is correspondingly protected, but this time by a layer of horn
+which belongs to the hoof.
+
+After the preceding remarks, our study will be found to fall into a
+natural division, and it is in the order which we have just followed for
+the purpose of indicating its existence that we now proceed to study the
+nature and form of the different elements which complete or protect the
+digital extremities of the thoracic and abdominal limbs.
+
+=Claws.=--These horny coverings of the third phalanges, which we have to
+consider only in the dog and cat, may be compared with the nails of man,
+with which, however, they present, as is well understood, characteristic
+differences.
+
+The claws are compressed laterally, curved on themselves, and are
+terminated in front by a sharp point in the felide, but more blunted in
+the dog. Their superior border is convex and thick. We may say,
+therefore, that a claw is a sort of hollow tube, in the form of a cone
+flattened in the transverse direction, in which the third phalanx is
+set, and which is itself set in a groove formed by a kind of osseous
+hood which occupies the base of this third phalanx (see Fig. 37, p. 57).
+
+This definition is exact, as regards the general appearance; but, when
+more closely scrutinized, it is not sufficient. The tube in question is
+not formed of a single piece; each of the claws is formed by a lamina
+laterally folded, but of which the borders are not exactly joined
+together inferiorly; they leave between them a small interval, and this
+is filled by a layer of more friable horny substance, to which has been
+given the name of plantar nail. This arrangement, which is clearly
+defined in the dog (Fig. 93), is comparable to that which we shall
+afterwards meet with in connection with the sole of the hoof of the
+horse (see Fig. 100, p. 257). In the dog and the cat, the weight of the
+limb resting on the inferior surface of the phalanges, it was necessary
+that the region of the plantar surface of the foot corresponding to
+these latter should be protected; this is the function of certain
+fibro-adipose pads, which are situated there, and which are designated
+by the name of _plantar tubercles_.
+
+=Plantar Tubercles= (Fig. 94).--These tubercles, or dermic cushions, are
+divided, in each paw, into _tubercles of the digits_ (or of the toes), a
+_plantar tubercle_, and, on the fore-limbs, a _tubercle of the carpus_.
+
+The tubercles of the fingers (or of the toes) are of the same number as
+the latter. That which belongs to the thumb is but little developed, but
+the others are more so. They are in relation with the plantar surfaces
+of the second and third phalanges, so that when the paw is in contact
+with the ground the articulation which, in each of the fingers or toes,
+joins these phalanges, rests on the corresponding pad.
+
+The plantar tubercle is larger than the preceding. It is of a more or
+less rounded form; sometimes it is triangular, and then comparable in
+outline to the ace of hearts, the point of which is, in this case,
+turned towards the claws; its margin being sometimes strongly indented,
+it may also have a trilobate form. It is on it that rest the
+metacarpo-phalangeal or metatarso-phalangeal articulations, according to
+the limb studied. The tubercle of the carpus, situated at the level of
+the posterior surface of this latter, is less important than the
+preceding, the region which it occupies not reaching the ground during
+walking. But it is not to be neglected from the point of view of
+external form, because of the prominence which it produces.
+
+[Illustration: FIG. 93.--CLAW OF THE DOG: INFERIOR SURFACE.
+
+1, Horny lamina of the claw; 2, plantar nail; 3, tubercle of the
+corresponding digit.]
+
+[Illustration: FIG. 94.--LEFT HAND OF THE DOG: INFERIOR SURFACE, PLANTAR
+TUBERCLES.
+
+1, 1, 1, 1, 1, Tubercles of the fingers; 2, plantar tubercle; 3,
+tubercle of the carpus.]
+
+In the ungulates the terminal extremity of the limb is, as we have above
+pointed out, enclosed in a horny envelope which is no other than the
+hoof.
+
+We will first study the hoof of the horse--a hoof which is single for
+each of the limbs, inasmuch as in this animal each of these has but a
+single digit.
+
+=Hoofs of the Solipeds.=--We will first study the hoof as regarded in a
+general way--that is, without taking into account the limb to which it
+belongs. We will afterwards point out the differences presented when the
+hoofs of the fore and hind limbs are compared.
+
+In connection with the external forms of the horse, the study which we
+are now commencing is of great importance. But, before entering upon it,
+it appears to us necessary to rapidly examine what the hoof contains
+(Fig. 95).
+
+[Illustration: FIG. 95.--VERTICAL ANTERO-POSTERIOR SECTION OF THE FOOT
+OF A HORSE.
+
+1, Third phalanx; 2, fibro-cartilage; 3, podophyllous tissue; 4,
+inferior part of the wall; 5, section of the wall of the hoof; 6,
+cutigerous cavity; 7, tendon of the anterior extensor of the phalanges;
+8, reinforcing band coming from the suspensory ligament of the fetlock;
+9, tendon of the superficial flexor of the phalanges; 10, tendon of the
+deep flexor of the phalanges.]
+
+In the interior of this horny box we find the third phalanx, a small
+sesamoid bone placed opposite to the posterior border of the latter, a
+portion of the inferior extremity of the second phalanx, and the
+tendons, which terminate at this region.
+
+To the third phalanx are added two fibro-cartilaginous plates, flattened
+laterally, which prolong backwards the bone to which they are annexed.
+The inferior border of each of these fibro-cartilages is fixed by its
+anterior part to two osseous prominences situated at each of the angles
+which terminate the small phalanx behind; these prominences are: _the
+basilar process_ and _the retrorsal process_ (Fig. 96); by its posterior
+part, this border is continuous with a structure known as _the plantar
+cushion_ (see further on).
+
+The posterior border is directed obliquely upwards and forwards. The
+superior border, which is convex or rectilinear, is thin, and is
+separated from the posterior border by an obtuse angle. Finally, the
+anterior border, which is directed obliquely downwards and backwards, is
+united to the ligamentous apparatus, which keeps the second and third
+phalanges in contact.
+
+These fibro-cartilages, at their upper extremities, project beyond the
+hoof, and therefore assist in the formation of the lateral regions of
+the foot,[35] at the part which is called the _crown_. They project less
+above the hoof in the posterior limbs.
+
+  [35] Here, for the first time, apropos of the hoof, we use the word
+       'foot.' As in osteology and in myology we have, for the sake of
+       clearness of comparison, designated under this name the region
+       limited above by the tarsus, it is necessary to point out here
+       that we employ the same word for a more restricted region. This
+       we did in conformity with the usage of veterinarians, who so
+       designate the region of the hoof. It is necessary to explain this
+       double employment of the word, and, further, to show the
+       particular meaning ascribed to it.
+
+[Illustration: FIG. 96.--THIRD PHALANX OF THE HORSE: LEFT ANTERIOR LIMB,
+EXTERNAL SURFACE.
+
+1, Pyramidal eminence; 2, surface, for articulation with the inferior
+extremity of the second phalanx; 3, basilar process; 4, retrorsal
+process.]
+
+The posterior and inferior borders of these cartilages meet at an acute
+angle. The angle so formed, or cartilaginous bulb, constitutes the base
+of the region, which is commonly called the _heel_--a part of the foot
+which, as its name implies, is situated posteriorly, but which we must
+not confound, as we might be led to do, with the region occupied by the
+calcaneum. We know from our previous studies of comparative osteology
+that this latter is situated much higher up.
+
+The _plantar cushion_ is a sort of fibrous wedge which occupies the
+interval bounded by the fibro-cartilaginous plates which we have just
+been studying. Its inferior surface, the form of which we shall find to
+be reproduced by a portion of the corresponding surface of the hoof, is
+prolonged anteriorly into a point, while behind it is divided into two
+branches, which, diverging from one another, join the posterior angles
+of the fibro-cartilages. These two branches are separated by a median
+excavation.
+
+The different constituent elements which we have just been discussing
+give elasticity to the foot.
+
+To finish the examination of the parts contained in the hoof, we will
+add that among them is also found what is called the fleshy _envelope_,
+or _flesh_ of the foot.
+
+We divide the latter into three regions: the podophyllous tissue,
+striated or laminated flesh which is spread out over the anterior
+surface of the third phalanx; the pad, or the hardened skin which
+corresponds to the upper border of the hoof, and forms a prominence
+above the podophyllous tissue; and the villous flesh, or velvety tissue
+which covers the plantar surface of the third phalanx and the plantar
+cushion. These three tissues form as a whole the keratogenic
+membrane--that is to say, that which produces horny tissue, and
+consequently regenerates the hoof.
+
+It is this latter that we now proceed to study.
+
+When we examine its anterior surface or the opposite one, the hoof of
+the horse has the shape of a truncated cone with the base below and the
+summit cut off obliquely downwards and backwards (Fig. 97).
+
+Viewed on one of its lateral aspects, it may be compared to a truncated
+cylinder placed on the surface of the section (Fig. 98). We particularly
+call attention to this latter comparison, for it singularly aids us in
+making a representation of the foot of the horse when viewed laterally.
+
+Notwithstanding that the hoof forms apparently a homogeneous whole, it
+consists of three parts, which may be separated from one another by
+maceration. The indication of such disunion, artificially produced, may
+seem useless. It is not so, however, for this division of the hoof will
+permit us to carry out the study of the latter in a clearer, and
+consequently a more satisfactory, way. The three parts in question are
+the _wall_, or _crust_, the _sole_, and the _frog_.
+
+The _wall_ is that portion of the hoof which we see when the foot rests
+on the ground. It is a plate of horn which, applied to the anterior and
+lateral surfaces of the foot, diminishes in height as it approaches the
+posterior part of the region. Posteriorly and at each side the wall is
+folded on itself, and is then directed forwards to terminate in a point,
+after having enclosed the frog, which we will soon study.
+
+[Illustration: FIG. 97.--LEFT ANTERIOR FOOT OF THE HORSE: ANTERIOR
+ASPECT.
+
+1, Outer side; 2, inner side.]
+
+Although the wall forms a continuous whole, it has been divided into
+regions to which special names are given. The anterior part, from the
+superior border to the inferior, is called the _pince_ or _toe_ for a
+width of 4 to 5 centimetres. External to the toe, and on each side of
+it, for a distance of 3 or 4 centimetres, is the _nipple_. Behind the
+_nipples_ are the _quarters_. Still further back, where the wall folds
+on itself, forming the _buttress_, is found the region of the _heels_.
+Finally, the portions of the wall which form its continuation in passing
+forward are called the _bars_.[36] These are only visible on the
+inferior surface of the hoof (see Fig. 100).
+
+  [36] It is to the angle of inflexion or heel that some authors give
+       the name of buttress; it is the bars which other authors
+       designate in this fashion.
+
+The wall, convex transversely, is, in its anterior part (viz., the
+_toe_) inclined strongly downwards and forwards. This obliquity tends to
+become gradually effaced on the lateral parts to such a degree that at
+the quarters it becomes almost perpendicular to the surface of the
+ground.
+
+The internal quarter is less rounded than the external; in addition to
+this (Fig. 97), it approaches more nearly to the vertical direction.
+
+[Illustration: FIG. 98.--LEFT ANTERIOR FOOT OF THE HORSE: EXTERNAL
+ASPECT.
+
+1, Fetlock; 2, spur or beard; 3, pastern; 4, outline determined by the
+external fibro-cartilage; 5, acute angle; 6, nipple; 7, quarter; 8,
+heel.]
+
+In our opinion, this latter difference clearly recalls certain
+characters of the general form of the human foot. In fact, the latter
+has its dorsal surface inclined downwards and outwards, whereas its
+internal border may be said rather to be vertical. A transverse section
+of the foot (Fig. 99) justifies this comparison, which to us appears
+interesting, not only as regards the resemblance which exists between
+these organs of support, but, further, because it constitutes a mnemonic
+which enables us, on condition that we remember the form of the human
+foot, to recall the above-described character of that of the horse.
+
+The greater convexity of the outer portion of the hoof is found equally
+on the human foot; the external border of this foot is more convex than
+the opposite one.
+
+The inferior border of the wall (Fig. 100) is, in the case of unshod
+horses, always in wear when in contact with the ground. It is intimately
+united to the circumference of the sole (see further on).
+
+[Illustration: FIG. 99.--VERTICAL AND TRANSVERSE SECTION OF A LEFT HUMAN
+FOOT: OUTLINE OF THE DIVIDED SURFACE OF THE POSTERIOR SEGMENT OF THIS
+SECTION (DIAGRAMMATIC FIGURE).
+
+AA', Vertical axis passing through the middle of the leg and the second
+toe; 1, outer side; 2, inner side.]
+
+The superior border is hollowed on its internal surface by a groove, the
+cutigerous cavity or basil, which lodges the cushion (see Fig. 95). We
+have described this latter above, in connection with the flesh of the
+foot.
+
+The substance of the wall presents a fibrous appearance which is pretty
+strongly pronounced. The constituent fibres from which this appearance
+results are directed from the superior border towards the inferior in
+parallel and regular lines.
+
+The _sole_ is a horny plate which occupies the inferior surface of the
+hoof (Fig. 100). It is situated between the inferior border of the wall
+and the bars; and, on account of the oblique direction of these latter,
+it presents a strongly-marked groove of a [V]-form, with the opening
+directed backwards. In this depression is lodged the frog.
+
+The inferior surface is concave, and thus forms a sort of vault, more or
+less deep, according to the individual. The sole has a scaly, laminated
+aspect.
+
+We have seen (Fig. 93, and p. 249) that on the inferior surface of the
+claws of carnivora is found a small interval which is filled by a plate
+of a more friable horny substance, to which has been given the name of
+the plantar nail. It seems to us that there is an interesting
+relationship between the said plantar nail and the sole which we have
+just been studying.
+
+[Illustration: FIG. 100.--INFERIOR SURFACE OF A FORE-HOOF OF THE HORSE:
+LEFT SIDE.
+
+1, Internal border of the wall (toe); 2, wall; 3, quarter; 4, heel; 5,
+bar; 6, sole; 7, frog; 8, median cavity; 9, prominence of the frog; 10,
+lateral cavity.]
+
+Indeed, these two horny structures appear to be homologous. Is not the
+lamina of the claw comparable to the wall of the hoof? And does not the
+interval which occurs at the inferior part of this latter, and is filled
+by the sole, recall that which, in extremely reduced form, is filled by
+the plantar portion of the claws?
+
+The _frog_ (Fig. 100) is a mass of horn, in form of a wedge, with its
+apex in front, which occupies the space limited laterally by the
+recurved portions of the wall (the bars) and the posterior border of the
+sole.
+
+It covers the plantar cushion previously described (p. 252) and
+reproduces its form.
+
+Its inferior surface is hollowed out in the middle by an excavation,
+which is known as the _median lacuna_. This cavity separates the
+branches of the frog, which terminate posteriorly by two swellings which
+are known as _the prominences of the frog_, forming two rounded
+elevations situated above the claws. These same branches unite in front
+of the median lacuna to form the body of the frog. This latter, in its
+anterior part, gradually narrows, and terminates in a point which
+occupies the bottom of the hollow limited laterally by the bars of the
+wall and the posterior border of the sole.
+
+Between the lateral surfaces of the frog and the bars are found two
+angular cavities--_the lateral lacunae_, or the _commissures of the
+frog_.
+
+[Illustration: FIG. 101.--THIRD PHALANX OF THE HORSE: LEFT ANTERIOR
+LIMB, INFERIOR VIEW.
+
+1, External border; 2, internal border; 3, semilunar crest; 4, 4,
+re-entrant processes.]
+
+[Illustration: FIG. 102.--THIRD PHALANX OF THE HORSE: LEFT POSTERIOR
+LIMB, INFERIOR VIEW.
+
+1, External border; 2, internal border; 3, semilunar crest; 4, 4,
+re-entrant processes.]
+
+As an indispensable complement to the study which we have just
+made, it is necessary to add that the hoofs of the fore-limbs and
+those of the hind ones present differences of form which cannot be
+ignored--differences which we are already able to conjecture by looking
+at the respective third phalanges which terminate those limbs, and
+especially at their inferior surfaces (Figs. 101, 102).
+
+The hoofs of the fore-limbs (see Fig. 100), viewed on their plantar
+surface, are more rounded than those of the hind-limbs (Fig. 103)--so
+that their external contour may be compared to a semicircle--whilst the
+hind-hoofs, which are narrow and of more oval shape, rather recall by
+their form the aspect of an ogive.
+
+This seems to result from the fact that the fore-limbs support the more
+considerable part of the weight of the animal. The best proof which can
+be given of this overweighting is the eagerness with which very often,
+when a horse is stopped near the edge of a footpath, for example, he
+places his fore-feet on the latter. In thus raising his fore-quarters,
+he throws part of his weight backwards, and in this way relieves his
+fore-limbs.
+
+[Illustration: FIG. 103.--INFERIOR SURFACE OF A HIND-HOOF OF A HORSE:
+LEFT SIDE.
+
+1, External border; 2, internal border.]
+
+With regard to the difference of form which we have just pointed out, we
+have sometimes heard the following comparison made: the contour of the
+hoofs of the fore-limbs, viewed from below, recalls that of an apple;
+that of the hoofs of the hind-limbs recalls the outline of a pear.
+
+As a mnemonic this comparison is insufficient, for nothing connects
+either of the forms indicated with the region to which the hoofs belong.
+
+We much prefer one made for us this very year by one of the students of
+our course at the School of Fine Arts, after the lecture in which we had
+just pointed out the differences in question. Giving the idea of a
+semicircle and an ogive, which we described above, he remarked to us
+that the idea would perhaps be more easily fixed in the memory if we
+associated with it the idea of the chronological order in which the
+Roman and ogival art succeeded. Indeed, as the Roman art preceded the
+ogival art, so the hoofs which have the semicircular form precede those
+which have the form of an ogive.
+
+This interpretation appeared to us ingenious; this is why we wished to
+give it here a place which seems to us to be merited.
+
+[Illustration: FIG. 104.--LEFT POSTERIOR FOOT OF A HORSE: EXTERNAL
+ASPECT.]
+
+The wall of the hoof of a fore-limb, viewed on one of its lateral
+surfaces (see Fig. 98), is more oblique than that of one of the
+hind-hoofs looked at in the same way (Fig. 104). This difference, very
+marked especially at the region of the toe, is correlated with that of
+the direction of the pastern. In fact, in the anterior limbs this is a
+little more oblique than in the opposite ones.
+
+We have still to describe, in connection with the horse, some epidermic
+tissues, which are known as _chestnuts_.
+
+The chestnut is a small, horny plate which is found on the internal
+surface of each of the limbs, at a level differing on the anterior from
+that of the posterior ones.
+
+On the anterior limbs the chestnut is situated on the internal surface
+of the forearm, towards the middle part, or the inferior third of this
+region. On the posterior limbs it is developed on the back of the
+superior extremity of the internal surface of the canon, towards the
+inferior part of the ham--that is, the tarsus.
+
+[Illustration: FIG. 105.--FOOT OF THE OX: LEFT SIDE, ANTERO-EXTERNAL
+VIEW.
+
+1, Internal hoof; 2, external hoof; 3, internal surface of this latter;
+4, internal spur.]
+
+Inasmuch as some authors consider the chestnuts as being vestiges of the
+thumb and the great-toe, we propose giving a mnemonic which will enable
+us to remember their situation, or, rather, their difference of level.
+
+If we consider that the thumb, in the human species, is longer than the
+first toe, we may easily remember that the chestnut is placed higher in
+the anterior limbs than in the posterior ones. Indeed, if we suppose a
+digit taking its origin at these points, it will be longer in front (the
+thumb) than behind (the first toe).
+
+=Hoofs of the Ox and the Pig.=--The ox has four hoofs on each foot--two
+which contain the third phalanges, and two others, rudimentary, situated
+at the posterior aspect of the limb, at the level of the inferior part
+of the canon; these latter bear the name of _spurs_. We will occupy
+ourselves especially with the former (Fig. 105).
+
+Each of the hoofs presents three faces which, if we consider them in
+relation to the median axis of the limb to which they belong, are:
+external, internal, and inferior. The external surface resembles the
+wall of the hoof of the horse. The internal surface is slightly concave
+from before backwards, so that the external and internal hoofs of the
+same foot are not in contact with each other, except by the extremities
+of this surface, and that an interval separates them between these two
+points. The inferior surface, slightly depressed, ends behind in a
+swelling produced by the plantar cushion, which covers a thin lamina of
+horn.
+
+At the anterior part of the hoof these three surfaces unite in forming a
+well-marked angle which, on account of the concavity of the internal
+surface, is slightly curved towards the axis of the foot.
+
+The pig has also four hoofs--two for the great digits and two for the
+lateral digits. They recall those of the ox.
+
+
+
+
+CHAPTER IV
+
+PROPORTIONS
+
+
+Inasmuch as we have taken for granted, in connection with the present
+volume, that before entering on the study of the anatomy of quadrupeds
+the reader was prepared for it by a sufficient knowledge of human
+anatomy, it is quite natural that we should extend the same supposition
+to the study of proportions.
+
+For this reason, the definition of proportions, considered from a
+general point of view, their signification, their function and their
+utility, are questions which it would be superfluous to enter upon here.
+We will content ourselves by calling to mind that the common measure
+chosen by preference is the length of the head, and that, ordinarily, it
+is with it that we compare the dimensions of other parts.
+
+Among the animals whose structure we have examined, there is one of
+which the proportions deserve to be marked in preference to every other:
+this is the horse.
+
+Wherefore this preference? In the first place, it is because of the
+overwhelming position which this animal occupies in the artistic
+representation of quadrupeds; that it is more frequently associated with
+man; that, notwithstanding its division into different races, its
+general proportions may be referred to a special type.
+
+It is also because the indications relative to these proportions will
+suffice to show the way which the artist must follow in order to find
+for himself, at the time when the necessity for it arises, the
+proportions which characterize the other animals.
+
+Our intention is not, in connection with the subject which now occupies
+us, to enter into a deep discussion on the various opinions which have
+been set forth. We desire, above all, to give some indications which,
+from the practical point of view, can be utilized in the representation
+of the horse, and at the beginning to demonstrate the advantages of
+these indications. Now, there is a fact which we have had occasion to
+note; it is the following: almost invariably, when a person who is
+little accustomed to represent the horse, or not previously informed of
+certain proportions of lengths, begins to draw from nature, the error
+generally committed is that of making the head too small and the body
+too long. Is it a preconceived idea which is the cause that one regards
+them in this manner? Perhaps. At all events, certain artists who have
+made the representation of horses their special study have even had this
+habit. It is therefore necessary to be informed of the proportions; this
+is the object of the study which we are now undertaking.
+
+Bourgelat,[37] in the eighteenth century, fixed for the first time and
+in complete fashion the proportions of the horse; it is he,
+consequently, who created the aesthetics of the horse. It is but justice
+to recall the fact. His system has a point of analogy with that which is
+employed to determine the human proportions. Indeed, Bourgelat chose the
+length of the head as a standard of measurement, and the subdivisions of
+the head for measures of less extent. 'Since beauty,' said he,[38]
+'resides in the congruity and proportion of the parts, it is absolutely
+necessary to observe the dimensions, individual and relative, and in
+order to acquire a knowledge of the proportions, to assume a kind of
+measure which can be indiscriminately common for all horses. The part
+which can serve as a standard of proportion for all the others is the
+head. Take a measurement between two parallel lines--one tangent to the
+nape of the neck or the summit of the forelock, the other tangent to
+the extremity of the anterior lip--a line perpendicular to these two
+tangents will give you its geometrical length. Divide this length into
+three portions, and give to these three parts a special name, which may
+be applied indefinitely to all heads--as, for example, that of _prime_.
+Any head whatsoever will, accordingly, in its geometrical length, always
+have three _primes_; but all the parts which you will have to consider,
+whether in their length, in their height, or in their width, cannot
+constantly have either one prime, or a prime and a half, or three
+primes; subdivide, then, each _prime_ into three equal parts, which you
+will name _seconds_, and as this subdivision will not suffice to give
+you a just measure of all the parts, subdivide anew each _second_ into
+twenty-four _points_, so that a head divided into three _primes_ will
+have, by the second division, nine _seconds_, and two hundred and
+sixteen _points_ by the last.'
+
+  [37] Claude Bourgelat, founder of the veterinary schools in France. He
+       was born at Lyons in 1712, and died at Paris in 1779.
+
+  [38] Bourgelat, 'Elements de l'art veterinaire. Traite de la
+       conformation exterieure du cheval,' Paris, edition of 1785, p.
+       133.
+
+But where this system appears to us to have lost somewhat of its unity
+is when the author transforms it, in pointing out the following mode of
+procedure: 'But the head itself may err by default of proportion. This
+part is not, indeed, considered as either too short or too long, too
+thin or too thick, but by comparison with the body of the animal. Now,
+the body, being required to have--whether in length, reckoning from the
+point of the arm to the prominence of the buttock, or in height,
+reckoning from the summit of the withers to the ground--two heads and a
+half; whenever the head, by its geometrical length, shall give, in
+length or in height, to the body measured more than two and a half times
+its own length, it will be too short; and if it gives less, it will be
+too long.
+
+'In the case in which one of these faults exists there would be no
+further question of establishing by its geometrical length the
+proportions of the other parts. Give up this common measure, and measure
+the height or the length of the body; divide the length or the height
+into five equal portions; take, then, two of these divisions, divide
+them into _primes_, _seconds_, and _points_, corresponding to the
+divisions and subdivisions which you would have made of the head, and
+you will have a common measure, such as the head would have given you if
+it had been proportionate.'[39]
+
+  [39] Bourgelat, _loc. cit._, p. 135.
+
+[Illustration: FIG. 106.--THE PROPORTIONS OF THE HORSE (AFTER
+BOURGELAT).
+
+_To face p. 265._]
+
+We understand, up to a certain point, that Bourgelat may have been able
+to give this advice which, generally speaking, is sufficiently
+practical, since, in certain cases, he was able to pronounce that such a
+head was too small or too large. But it is always mischievous, with
+regard to the effect produced on the reader, to propose to him, in the
+application of a rule, to suppress the foundation on which this rule is
+established. Besides, even if all the measurements compared with the
+two-fifths of the length of the body are proportionate with regard to
+one another, the animal, in spite of this, since the head must be taken
+into consideration, will, in a strict sense, be none the less
+disproportioned.
+
+The proportions given by Bourgelat are as follows[40] (Fig. 106):
+
+  [40] _Ibid._, p. 136, and onward.
+
+1. =Three geometrical lengths of the head= give:
+
+_The full height_ of the horse, reckoned from the forelock to the ground
+on which he rests, provided that the head be well placed.[41]
+
+  [41] By 'the head being well placed,' Bourgelat means 'vertically
+       posed,' the outline of the forehead then coinciding with a
+       vertical line, which at the other end touches the anterior
+       portion of the nose.
+
+2. =Two heads and a half= (B)[42] equals:
+
+  [42] The letters in parentheses relate to the corresponding measures
+       marked by the same letters on the third diagram of Fig. 106.
+
+_The height of the body_ from the summit of the withers to the ground.
+
+_The length of the same body_, those of the forehand and of the
+hind-quarter taken as a whole from the point of the arm to the point of
+the buttock inclusive.
+
+3. =An entire head= (A) gives:
+
+_The length of the forepart_ from the summit of the withers to the
+termination of the neck.
+
+_The height of the shoulders_ from the summit of the elbow to the top of
+the withers.
+
+_The thickness of the body_ from the middle of the belly to the middle
+of the back.
+
+_The width_ from one side to the other.
+
+4. =A head measured from the top of the forelock to the commissure of
+the lips= (C). This measurement slightly curtailed, unless the mouth is
+very deeply cleft, equals:
+
+_The length of the crupper_, taken from the superior point of the
+anterior angle of the ilium to the tuberosity of the ischium, forming
+the point of the buttock.
+
+_The width of the crupper or of the haunches_, taken from the inferior
+points of the angles of the ilia.
+
+_The height of the crupper_, viewed laterally, taken from the summit of
+the posterior angles of the ilia to the point of the patella, the leg
+being in a state of rest.
+
+_The lateral measure of the posterior limb_, from the point of the
+patella, to the lateral and salient part of the ham, to the right of the
+articulation of the tibia with the trochlea.
+
+_The perpendicular height of the articulation above named_ above the
+ground.
+
+_The distance from the point of the arm_ to the angle formed by the
+junction of the head and neck.
+
+_The distance from the summit of the withers_ to the junction of the
+neck with the thorax.
+
+5. =Twice this last measure= (C)[43] gives almost:
+
+  [43] The proportions given in the two paragraphs 6 and 7 are, under
+       another form, the same as those pointed out in paragraph 2, with
+       this difference, that in this latter they are more clearly
+       expressed.
+
+_The distance of the summit of the withers_ to the tip of the patella.
+
+_The distance of the point of the elbow_ to the summit of the crupper or
+the posterior angles of the ilia.
+
+6. =Three times this measure, plus a half-width of the pastern, the
+equivalent of two heads and a half=, will give:
+
+_The height of the body_, taken from the top of the withers to the
+ground.
+
+_Its length_, taken from the point of the arm to the point of the
+buttock inclusive.
+
+7. =This same measure, plus the entire width of the pastern=, gives:
+
+_The total length of the body_, taken accurately.
+
+8. =Two-thirds the length of the head= (D) will equal:
+
+_The width of the chest_, from the tip of one arm to that of the other,
+from outside to outside.
+
+_The horizontal measurement of the crupper_ taken between two verticals,
+of which one forms a tangent to the buttock, and the other passes
+through the summit of the crupper and touches the tip of the patella.
+
+_The third of the length of the hind-quarter and of the body_ taken
+together, as far as the vertical from the withers, touching the elbow.
+
+_The anterior length of the hind-limb_, taken from the tuberosity of the
+tibia to the fold of the ham.
+
+9. =One-half of the length of the head= (E) is the same as:
+
+_The horizontal distance from the tip of the arm_ to the vertical line
+from the summit of the withers and touching the elbow.
+
+_The width of the neck_, viewed laterally, taken from its insertion in
+the trough of the jaw to the roots of the first hairs of the mane, on a
+line which forms with the superior contour two equal angles.
+
+10. =One-third of the entire length of the head= (F) gives:
+
+_The height of its superior part_ from the summit of the forelock to a
+line which passes through the most salient points of the orbits.
+
+_The width of the head_ below the lower eyelids.
+
+_The lateral width of the forearm_, taken from its anterior origin to
+the point of the elbow.
+
+11. =Two-thirds of this length=[44] (G) gives:
+
+  [44] That is to say, two-ninths of the whole length of the head.
+
+_The distance of the point of the elbow_ above the plane of the lower
+surface of the sternum.
+
+_The depression of the back_ in relation to the summit of the withers.
+
+_The lateral width of the posterior limbs near the hams._
+
+_The space or distance of the forearms from one ars_[45] to the
+opposite.
+
+  [45] We call the region where the superior and internal part of the
+       forearm is joined to the trunk the 'ars.' The space between the
+       ars of one side and the ars of the opposite side is called the
+       'inter-ars.'
+
+12. =One-half of the third of the entire length of the head=[46] (H)
+equals:
+
+  [46] That is to say, one-sixth of the total length of the head.
+
+_The thickness of the forearm_, viewed from the front, and taken
+horizontally from the ars to its external surface.
+
+_The width of the crown of the fore-feet_ whether from one side to the
+other, or from before backwards.
+
+_The width of the crown of the hind-feet_, from one side to the other
+only.
+
+_The width of the posterior fetlocks_, taken from the front to the
+origin of the spur.
+
+_The width of the knee_ seen from the front. Note: this measure is a
+little too large.
+
+_The thickness of the ham._ Note: this measure is a little under the
+mark.
+
+13. =One-fourth of the third of the length of the head=[47] (I) gives:
+
+  [47] That is, one-twelfth of the length of the head.
+
+_The thickness of the canon of the fore-limb_: that of the hind-quarter
+is a little thicker.
+
+14. =One-third of this same measure=[48] (K) equals:
+
+  [48] That is, a ninth of the length of the head.
+
+_The thickness of the fore-limb close to the knee_ in its narrowest
+part.
+
+_The thickness of the posterior pasterns_, viewed laterally.
+
+15. =The height from the elbow to the fold of the knee= (L) is the same
+as:
+
+_The height from this same fold to the earth._
+
+_The height from the patella to the fold of the ham._
+
+_The height from the fold of the ham to the crown._
+
+16. =The sixth part of this measure= (M) gives:
+
+_The width of the canon of the fore-limb_, viewed laterally, in the
+middle of its length.
+
+_The fetlock_, viewed from the front.
+
+17. =The third of this same measure= (N) is very nearly equal to:
+
+_The width of the ham_, from the fold to the point.
+
+18. =A fourth of this measure= (O) gives:
+
+_The width of the knee_, measured laterally.
+
+_The length of the knee._
+
+19. =The interval between the eyes from one great angle to the other=
+(P) equals:
+
+_The width of the hind-leg_, viewed laterally, from the cleft of the
+buttocks to the inferior part of the tuberosity of the tibia.
+
+20. =One-half of this interval between the eyes= (1/2 P) gives:
+
+_The width of the posterior canon-bone_, viewed laterally.
+
+_The width of the fetlock of the fore-limb_, from its anterior summit to
+the root of the spur.
+
+Finally, the difference of the height of the crupper with respect to the
+summit of the withers.
+
+It is certain that the multiplicity of these proportions, and above all
+the exaggeration of details into which Bourgelat fell in indicating
+certain of the measures which constitute the bases of some of them, may
+repel the reader.
+
+For this cause we desire to add to the preceding, and also because the
+question which we are treating would be incomplete without it, the
+results obtained and published by other more modern authors, and in
+particular by Colonel Duhousset.[49]
+
+  [49] E. Duhousset, 'Le Cheval,' Paris, 1881.
+
+This author, one of whose constant occupations is the measurement of the
+different regions of the horse, has the incontestable merit of having
+drawn attention to this question, and of having strained all his
+energies in the propagation of the knowledge which until then was little
+diffused. Among the proportions which he recommends, there are some
+which are the result of his own observations; whilst others, which he
+has verified and adopted, are the result of a judicious selection of
+those given by Bourgelat, which we have just reproduced in the preceding
+pages.
+
+We join thereto also certain indications furnished by MM. A. Goubeaux
+and G. Barrier,[50] distinguishing these latter by the initials (G. and
+B.) of their authors (Fig. 107).
+
+  [50] Armand Goubeaux and Gustave Barrier, 'De l'exterieure du Cheval,'
+       Paris, 1882.
+
+=The length of the head almost exactly equals=:
+
+1. Depth from the back to the belly, N, O,[51] the thickness of the
+body.[52]
+
+  [51] Look for the points indicated by these letters on Fig. 107, which
+       is related to the proportions which are here discussed.
+
+  [52] The proportion previously indicated by Bourgelat (see p. 265,
+       paragraph 3).
+
+2. From the summit of the withers to the point of the arm, H, E.
+
+3. From the superior fold of the stifle to the point of the ham, J', J.
+
+4. From the point of the ham to the ground, J, K.
+
+5. From the dorsal angle of the scapula to the point of the haunch, D,
+D.
+
+[Illustration: FIG. 107.--PROPORTIONS OF THE HORSE (AFTER COLONEL
+DUHOUSSET).]
+
+6. From the passage of the girth to the fetlock, M, I, or higher in
+large horses and racers; to the middle of the fetlock or lower for small
+ones and those of medium size.
+
+7. From the superior fold of the stifle to the summit of the crupper in
+those specimens whose coxo-femoral angle is very open. This distance is
+always much less in others (G. and B.).[53]
+
+  [53] A proportion relative to the same region, and which at the outset
+       might appear similar, is pointed out by Bourgelat (see p. 266,
+       paragraph 4). But there exists a difference, for Bourgelat
+       compared the length of the head, measured from the forelock to
+       the commissure of the lips, and not that of the entire head, to
+       the distance which separates the summit of the rump and the tip
+       of the patella.
+
+=Two and a half times the length of the head= gives:
+
+1. The height of the withers, H, above the ground.[54]
+
+  [54] This proportion is that given by Bourgelat (see p. 265, paragraph
+       2).
+
+2. The height of the summit of the crupper above the ground.[55]
+
+  [55] Consequently the withers and the crupper, being the same height,
+       are situated on the same horizontal plane. Bourgelat, on the
+       contrary, points out a difference of level in connection with
+       these regions. According to him the summit of the crupper is
+       situated below the horizontal plane passing the withers, and this
+       distance equals half of the space which separates the great angle
+       of one eye from that of the other (see p. 269, paragraph 20).
+
+3. Very often the length of the body, from the point of the arm to that
+of the buttock, although for a long time the type of Bourgelat had been
+set aside as a conventional model, short and massive.[56]
+
+  [56] See p. 265, paragraph 2.
+
+And M. Duhousset adds to this:
+
+'The drawing that we offer, which has two heads and a half in height and
+length, is that of a horse which we frequently meet with' (see Fig. 107;
+see also p. 279, where we again consider this question of the length of
+the body of the horse).
+
+'The crupper, from the point of the haunch to that of the buttock, D, F,
+is always less than that of the head. This difference varies from 5 to
+10 centimetres. The width of the crupper, from one haunch to the other,
+often very slightly exceeds its length.' MM. Goubeaux and Barrier add
+that frequently it equals it.[57]
+
+  [57] If we refer to the proportions indicated by Bourgelat, we shall
+       find that the proportions relative to the crupper are also
+       indicated there (see p. 266, paragraph 4).
+
+'The crupper, such as we have just defined it, D, H, may also be found
+to a fair degree of exactness, as regards length, four times on the same
+horse.'
+
+1. From the point of the buttock to the inferior part of the stifle, F,
+P.
+
+2. The width of the neck, a little in front of the withers to a little
+above the point of the arm, S, X.[58]
+
+  [58] MM. Goubeaux and Barrier replace this by the following: 'The
+       width of neck at its inferior attachment from its insertion into
+       the chest to the origin of the withers, S, X.' Bourgelat
+       discovered the same proportion (see p. 266, last line of
+       paragraph 4).
+
+3. From this latter point to below the lower jaw, X, Q, when the head is
+naturally placed parallel to the shoulders, E, H.[59]
+
+  [59] MM. Goubeaux and Barrier replace this by the following: 'From the
+       insertion of the neck into the chest to the lower border of the
+       lower jaw, X, Q, when the head is parallel to the shoulder.'
+
+4. From the nape to the nostrils, _n, n'_.[60]
+
+  [60] MM. Goubeaux and Barrier add: 'Or to the commissure of the lips.'
+       It is thus, besides, that Bourgelat measured the head for
+       comparison with the crupper (see p. 266, paragraph 4).
+
+The measure of =half of the head= also acts as a good guide for the
+construction of the horse, when we know that it frequently applies to
+many of the parts--to wit:
+
+1. From the forehead above the eyes, perpendicular to the line which is
+tangent to the lower jaw, P, Q.
+
+2. Outline of the neck at the level of the base of the head, Q, L.[61]
+
+  [61] Proportion indicated by Bourgelat (see p. 267, paragraph 9).
+
+3. From the crown of the fore-foot to below the knee, T, T'.
+
+4. In the legs, from the base of the fetlock to that of the ham, U, V.
+
+5. Finally, it is nearly of the length of the humerus from the point E
+to the radius.[62]
+
+  [62] MM. Goubeaux and Barrier replace these by the following:
+
+       1. 'From the most prominent part of the lower jaw to the profile
+       of the forehead above the eye, P, Q (thickness of the head).
+
+       2. 'From the throat to the superior border of the neck behind the
+       nape, Q, L (attachment of the head).
+
+       3. 'From the inferior part of the knee to the crown, T, T'.
+
+       4. 'From the base of the ham to the fetlock, U, V.
+
+       5. 'Finally, from the point of the arm to the articulation of the
+       elbow (approximate length of the arm).'
+
+
+PROPORTIONS OF THE HEAD OF THE HORSE[63]
+
+  [63] Extract from the work of MM. Goubeaux and Barrier on the exterior
+       of the horse. As before, the initials G. and B. of these authors
+       are added.
+
+Although it is very difficult, says M. Duhousset, when we speak of
+measurements taken on the living animal, to formulate other than
+approximations, we believe we have determined with sufficient accuracy
+the following results, which are the outcome of our numerous
+observations. The head which we present is that of a horse which we have
+frequently come across as a mean term between the highly bred and the
+draught horse. Under this heading, it will not be devoid of interest to
+accompany with dimensions the two drawings to which are consigned the
+measurements in question.
+
+=Head viewed in Profile= (Fig. 108).--Length, A, B, from the nape to the
+margin of the lips, 0.60 metre.
+
+Thickness, C, D, from the angle of the lower jaw to the anterior surface
+(a half-head), 0.30 metre. This line passes through the middle of the
+eye, taken perpendicularly, to the profile of the anterior surface. Many
+common horses present it, especially the heavier draught horses; in
+finely-bred subjects it is a little shorter (G. and B.).
+
+Depth, I, H, of the neck in its narrowest part (a half-head), 0.30
+metre. It is frequently greater; this is noticeable in all instances
+where the superior parts of the neck are deficient in fineness. It is
+this which we see in draught horses, and in those which become too
+fleshy (G. and B.).
+
+Distance, O, R, of the internal commissure of the eye from the superior
+border of the commissure of the nostril (G. and B.) (a half-head), 0.30
+metre. It is more considerable on the common head, and on that which is
+too long.
+
+Distance, A, O, from the nape to the internal angle of the eye, 0.22
+metre. This distance is equivalent to the thickness of the head, P, Q,
+taken perpendicularly from the profile of the anterior surface, and
+passing at the level of the maxillary fissure and spine.
+
+It is, again, equal to Q, O, from the internal angle of the eye to the
+maxillary fissure; and to P, G, from the middle of the face to the
+commissure of the lips (G. and B.).
+
+The distance, P, E, from the middle of the face to the maxillary spine
+is about the sixth of the total length of the head--0.10 metre.
+
+[Illustration: FIG. 108.--PROPORTIONS OF THE HEAD OF THE HORSE, VIEWED
+IN PROFILE (AFTER COLONEL DUHOUSSET).]
+
+The line B, E, reckoned from the extremity of the lips to the maxillary
+spine, is equal:
+
+To E, F, from the maxillary spine to the external auditory meatus, to be
+seen only on the skull;
+
+To H, G, from the insertion of the neck in the trough to the commissure
+of the lips (G. and B.);
+
+To Q, R, from the maxillary fissure to the superior commissure of the
+nostril (G. and B.);
+
+To Q, B, from the fissure of the maxilla to the border of the lips (G.
+and B.);
+
+To O, D, from the internal angle of the eye to the angle of the lower
+jaw, provided that the line C, D be in proportion (G. and B.).
+
+[Illustration: FIG. 109.--THE SAME DESIGN AS THAT OF FIG. 108, ON WHICH
+WE HAVE INDICATED, BY SIMILAR LINES, THE PRINCIPAL CORRESPONDING
+MEASUREMENTS.
+
+Half the length of the head, and the dimensions which equal it; distance
+which separate the nape from the internal angle of the eye, and the
+dimensions which equal it; distance which separates the internal angle
+of the eye from the border of the lips, and the dimensions which equal
+it.[64]]
+
+  [64] It is thus that in our teaching, but by means of lines of
+       different colours, we present the proportions reproduced in Fig.
+       108. Experience has demonstrated to us that this replacement of
+       letters by conventional lines renders the proportions more easily
+       appreciable, and that these lines, striking the eye more
+       forcibly, then impress themselves better on the memory. Fig. 111
+       bears the same relation to Fig. 110.
+
+Finally, very frequently to O, H, from the internal angle of the eye to
+the insertion of the throat into the maxillary trough (G. and B.).
+
+An equality still more frequent is that which exists between the
+distances:
+
+O, B, from the internal angle of the eye to the margin of the lips;
+
+A, H, from the nape to the insertion of the throat into the maxillary
+trough;
+
+And H, B, from this latter point to the margins of the lips.
+
+[Illustration: FIG. 110.--PROPORTIONS OF THE HEAD OF THE HORSE, SEEN
+FROM THE FRONT (AFTER COLONEL DUHOUSSET).]
+
+=The Head, Front View= (Fig. 110).--If, to continue our examination,
+adds M. Duhousset, we regard the head from the front, we find its
+greatest width at A, B, the extreme points of the orbital arches.
+
+This width is 22 centimetres.
+
+It is again equal to:
+
+A, C, from one arch to the nape;
+
+A, D, from one arch to the middle of the face.
+
+D, E, from the middle of the face to the margin of the lips.
+
+From the auditory canal, G, to the maxillary spine, F, is the same
+distance as from this point to the margins of the lips, E, or, better,
+to the end of the teeth.
+
+[Illustration: FIG. 111.--THE SAME FIGURE AS FIG. 110, ON WHICH WE HAVE
+MARKED BY SIMILAR LINES THE PRINCIPAL MEASUREMENTS WHICH CORRESPOND
+THERETO.
+
+Distance which separates one of the orbital arches from that of the
+opposite side, and the dimensions which equal it; distance which
+separates the auditory meatus from the maxillary spine, and the
+dimensions which equal it; distance which separates one maxillary spine
+from that of the opposite side, and the dimensions which equal it;
+distance which separates the lip of one side from that of the opposite,
+and the dimensions which equal it.[65]]
+
+  [65] See the note relative to Fig. 109.
+
+The line G, C, from the auditory meatus to the nape, is equal to the
+sixth of the head, 10 centimetres; the line A, G, from the orbital arch
+to the auditory meatus, is a little longer, and measures 12
+centimetres.
+
+The distance F, I, comprised between the maxillary spines, is 18
+centimetres.
+
+It is equal to:
+
+O, O, the distance between the internal angles of the eyes (G. and B.);
+
+F, R, the distance from the maxillary spine to the superior commissure
+of the corresponding nostril (G. and. B.);
+
+F, P, from the maxillary spine to the _salt-cellar_.[66]
+
+  [66] We designate under the name _salt-cellar_ a depression situated
+       external to the frontal region and above the eye.
+
+From the nape to the internal angle of the eye, C, O, is the same
+distance as from this latter point to the commissure of the lips, O, T;
+and from the maxillary spine to the upper lip F, S (G. and B.).
+
+The distance apart, T, T, of the two commissures of the lips gives, very
+nearly, the distance from the superior border of the orbital arch to the
+base of the ear or the auditory meatus. In the state of rest, the outer
+limit of the separation of the nostrils does not exceed the width of the
+knee;[67] we frequently find the same distance intercepted above the
+nape by the tranquil ears. In the figure (Fig. 110) we have
+intentionally represented them directed in a different plane, in order
+to show that when the pinna is turned backward, it none the less
+preserves the contour of bracket form, more or less pronounced according
+to the breeding of the subject, and characterizing in repose the
+interior curves of the ear.
+
+  [67] We remind our readers that the name 'knee' is given by
+       veterinarians to the region occupied by the carpus.
+
+The extreme limit of the lips, M, N, but very slightly exceeds that of
+the nostrils; on many heads of harmonious proportions this distance is
+found to be the half of A, B.
+
+In order not to interrupt the course of the preceding exposition, we
+decided to withhold till afterwards some reflections which have been
+suggested to us by certain of the proportions which are there indicated.
+The proportions in question are important--we may even say that they are
+fundamental, for they have for object the relation which exists between
+the length of the head, the height of the body, and the length of the
+latter.
+
+We have already seen that, according to Bourgelat, the length of the
+head is contained two and a half times in the length of the body, from
+the point of the arm to the point of the buttock; and, also, two and a
+half times in the height measured from the apex of the withers to the
+ground (see p. 265). We saw afterwards that M. Duhousset, having adopted
+these proportions, pointed out, further, that the same dimension was
+again found equally to exist from the summit of the crupper to the
+ground--a height which Bourgelat considered as being of less extent.
+There results, then, from the latter proportions, which we have just
+recalled, this interesting fact: that they simplify very much, from the
+point of view of design, the placing in position of the horse, on the
+condition always that this latter be always viewed directly on one of
+its lateral aspects.
+
+[Illustration: FIG. 112.--HORSE OF WHICH THE LENGTH CONTAINS MORE THAN
+TWO AND A HALF TIMES THAT OF THE HEAD, AND OF WHICH THIS DIMENSION (A,
+B) EXCEEDS THE HEIGHT.]
+
+Indeed, in this case, if we except the neck and the head, the body,
+inasmuch as its height and its length are equal, may be inscribed in a
+square, of which one of the sides corresponds to the withers and to the
+summit of the crupper, two of the other sides to the point of the arm
+and to that of the buttock the fourth being represented by the ground.
+This is simple, but this simplicity even has its inconveniences.
+
+It follows that this proportion, thus expressed, seems to exclude from
+every artistic representation certain categories of horses, which upon
+the whole might be regarded as beautiful, and the existence of which in
+any case it would be a pity not to indicate.
+
+[Illustration: FIG. 113.--HORSE OF WHICH THE LENGTH CONTAINS MORE THAN
+TWO AND A HALF TIMES THAT OF THE HEAD, AND OF WHICH THIS DIMENSION (A,
+B) EXCEEDS THE HEIGHT.]
+
+Let us examine at the outset that which is relative to the length of the
+body, equal to two and a half times the length of the head. This
+proportion is sometimes met with, and therefore may be considered exact;
+but it is necessary to add that its existence is not discoverable in the
+majority of cases. That for some authors it constitutes a perfect model
+we will not gainsay, but it is our impression that, when it exists, the
+head appears a little large, or, more exactly, the body a little short.
+
+Without attaining exactly to three times the length of the head, as some
+authors (Saint-Bel, Vallon) have announced, the body of the horse,
+nevertheless, measured as is stated above, frequently contains it more
+than two and a half times. We give in support of this some outline
+reproductions, executed after photographs (Figs. 112, 113, 114).
+
+There still remains the question regarding the equality of the height
+and of the length of the body of the horse.
+
+This equality, after the proportions previously indicated, would seem
+bound to appear in all the cases observed. Now, if we measure the
+examples reproduced in Figs. 112, 113, and 114, we shall see that
+sometimes the two dimensions are unequal, the height being greater than
+the length, or inversely.
+
+[Illustration: FIG. 114.--HORSE OF WHICH THE LENGTH CONTAINS MORE THAN
+TWO AND A HALF TIMES THAT OF THE HEAD, AND OF WHICH THIS DIMENSION (A,
+B) IS INFERIOR TO THE HEIGHT.]
+
+It is the same, if we examine a certain number of specimens; we are able
+to determine that the proportion chosen in preference by authors is not
+exactly that which is oftenest met with. It will, very probably, be
+objected that it is so for the most beautiful types, and that the
+indifferent ones are generally the more numerous. The essential thing
+would be to know, above all, if the type of two heads and a half of
+length and of height is really the only beautiful one. However that may
+be, of the fifty African horses measured by M. Duhousset, only fourteen
+possessed the equality indicated; twenty-six were less long than high,
+and ten more long than high.[68]
+
+  [68] E. Duhousset, 'The Horse,' Paris, 1881.
+
+
+
+
+CHAPTER V
+
+THE PACES OF THE HORSE
+
+
+As a completion of the studies we have just been making, some notions
+relative to the paces of the horse seem to us to be absolutely
+indicated.
+
+Let it be permitted to us to remind the reader in this connection that
+we have already been for twenty-one years occupied with this question,
+and that by means of an articulated figure, a sort of movable mannikin,
+we have endeavoured to demonstrate to artists the differences which
+characterize the various paces of the horse.[69] The arrangement then
+employed cannot, evidently, be used in the present volume, but we will
+inspire ourselves, in the preparation of the present chapter, with the
+elements of demonstration which we have employed, and which, in the
+course of our teaching, we have had the satisfaction of seeing
+favourably received.
+
+  [69] Edouard Cuyer, 'Les Allures du Cheval,' demonstrated with the aid
+       of a coloured, separable, and articulated table, Paris, 1883.
+
+       This table was the subject of a note communicated to the Academy
+       of Sciences by Professor Marey ('Comptes rendus de l'Academie de
+       Sciences') at the meeting of June 26, 1882. On the other hand, it
+       has been the subject of a presentation which we have had the
+       honour of being permitted to make to the Academy of Fine Arts at
+       the meeting of November 4, 1882.
+
+       The fasciculus in question has been since united with a more
+       complete whole as regards the study of the horse. E. Cuyer and E.
+       Alex, 'Le Cheval: Exterieur, Structure et Fonctions, Races,' avec
+       26 planches coloriees, decoupees et superposees, Paris, 1886.
+
+The progressive movements by which an individual transports himself
+from one place to another do not operate according to a unique method
+and with a constantly uniform velocity. These various modes of
+progression are designated under the name of _paces_.
+
+It is extremely difficult to analyze, by simple observation, the
+movements which characterize these gaits. Let us, for example, examine
+the displacements made by the limbs of a horse during that of walking;
+if we have no notion of these displacements, it will be, so to speak,
+impossible to determine in what order they are executed. The sight of
+the imprints left on the ground by the hoofs is not a sufficient means
+of demonstration, especially for artists. The noise made by the blows of
+these limbs, or by the little bells of different timbre suspended from
+them, are absolutely in the same case.
+
+Processes enabling us to fix or to register the paces are in every way
+preferable. Such really exist; they are: instantaneous photography and
+those which constitute the graphic method of Professor Marey. The
+results given by the photograph are certainly appreciable; but, from the
+didactic point of view, we give the preference to the graphic method,
+the general characters and the mode of application of which we now
+proceed to analyze.[70]
+
+  [70] We cannot too strongly recommend the reading of the excellent
+       works which Professor Marey has published, and which have for
+       their object the study of movements, as well as the exhibition of
+       the procedures which he has employed. E. J. Marey, 'La Machine
+       Animale,' Paris, 1873; 'La Methode graphique dans les Sciences
+       experimentales,' Paris, 1884; 'Le Vol des Oiseaux,' Paris, 1890;
+       'Le Mouvement,' Paris, 1894.
+
+It is necessary to understand first of all, in this connection, that
+which relates to a man's walking pace.
+
+The method of Professor Marey rests on the following principle: Suppose
+two rubber globes connected with one another by a tube. If we compress
+one of these globes, the air which it contains will be driven into the
+other, and will afterwards return when the pressure has ceased. Nothing
+more simple, evidently; but it is necessary to describe it in detail in
+order the better to comprehend that which follows: The walker who is the
+subject of experiment is furnished with special shoes (Fig. 115), having
+thick indiarubber soles, hollowed in the interior, so that the whole
+thus constituted forms a sort of hollow cushion which is compressed
+under the influence of the pressure of the foot on the ground. A tube
+which is attached to a registering apparatus, which the person who is
+walking carries in his hand, communicates with this cavity (Fig. 116).
+This apparatus is formed of a metal drum, which is closed at its upper
+part by a flexible membrane. Each time that one of the man's feet
+presses on the ground, the air contained in the cavity of the sole of
+the shoe is driven into the drum, which we have just mentioned, and the
+flexible membrane of this drum is elevated. To this membrane is attached
+a vertical rod which supports a horizontal style.
+
+[Illustration: FIG. 115.--EXPERIMENTAL SHOES, INTENDED TO RECORD THE
+PRESSURE OF THE FOOT ON THE GROUND.]
+
+When the membrane, as we have just seen, is elevated, the style is
+lifted, and then descends when the pressure of the foot ceases. It
+traces these displacements on a leaf of paper, the surface of which is
+covered with a thin layer of lamp-black, which it removes by its
+contact; different parts of this surface are successively presented to
+it, the paper being rolled round a cylinder which is turned on its axis
+by means of a clockwork movement. It is necessary to add that the
+inscription is made, in the study of the walk of man, by means of two
+styles, each corresponding to one of the feet.
+
+The tracings thus obtained, which are read from left to right, are
+sufficiently simple; but to understand them properly, it is necessary to
+remember that the style undergoes a movement of ascensional displacement
+during each pressure of a foot, and that, on the other hand, it
+descends when the latter is separated from the ground. We also see, on
+the tracing which it leaves, a line which ascends and then descends; the
+meaning of this is that first the foot presses on the ground, and is
+afterwards raised from it.
+
+[Illustration: FIG. 116.--RUNNER FURNISHED WITH THE EXPLORATORY AND
+REGISTERING APPARATUS OF THE VARIOUS PACES.]
+
+On the tracing (Fig. 117), the line D relates to the right foot; the
+line G, which is dotted so that it may not be confused with the
+preceding, corresponds to the left foot. The line G first ascends; the
+meaning of which is that the left foot presses on the ground; afterwards
+it descends: this indicates that the pressure of the foot has ceased. It
+is the same for the right foot. As we see, the pressures succeed each
+other; when the left foot touches the ground, the right is separated
+from it; when the latter presses the ground, it is the left which no
+longer rests there.
+
+The line O is related to the movements of the body, as indicated by the
+oscillations of the head. We will neglect these.
+
+But this tracing, which serves us for an example, is not, it must indeed
+be said, of very easy reading; it would be still less so if the paces of
+a horse were registered, for there would then be four lines, the
+entanglement of which would cause greater complication.
+
+These difficulties of reading need be no longer feared, if we transform
+the tracing into a notation by means of the following diagram.
+
+There are drawn (Fig. 118) below the graphic tracing two horizontal
+lines (1, 2). From the point where the line D rises (commencement of the
+pressure of the right foot), and from the point where this same line
+descends (end of the same pressure), we let fall two vertical lines
+joining the two horizontal ones mentioned above. At this plane, and
+between the two vertical lines, we mark a broad white one (_a, b_). This
+expresses, by its length, the duration of the period of pressure of the
+right foot. In doing the same for the line G, we obtain for the
+indication of a pressure of the left foot an interval of the same kind,
+in which are marked cross-lines, or which is tinted gray, in order to
+avoid all confusion with the preceding tracing.
+
+[Illustration: FIG. 117.--TRACING OF THE RUNNING OF A MAN (AFTER
+PROFESSOR MAREY.)
+
+D, Pressures and elevations of the right foot; G, pressures and
+elevations of the left foot.]
+
+This notation can, with sufficient exactitude, be compared to that which
+is employed in the musical scale. The horizontal lines 1 and 2 represent
+the _compass_. We there also see _notes_; these are the bars indicating
+the pressure, of which the value--that is to say, the duration--is
+represented by the length of these bars. It is the same with regard to
+the intervals of _silence_: these are expressed by the intervals which
+separate the pressures, and correspond to the moments in which, during
+certain paces, such as running, the body is raised from the ground.
+Besides, we see intervals of this kind on the notation reproduced (Fig.
+118) relative to the running of man.
+
+[Illustration: FIG. 118.]
+
+[Illustration: FIG. 119.]
+
+In order to make the signification of these tracings still better
+understood, we reproduce four varieties of them (Fig. 119).
+
+The first notation is that of ordinary walking. The pressures succeed
+each other regularly.
+
+The second shows what takes place during the ascent of a staircase. At a
+certain moment, the weight of the body is upon both feet at the same
+time, one of them not quitting the lower step, until the other is
+already in contact with the step above. Accordingly, there is thus
+produced an overriding of the pressures.
+
+The third is relative to running, and has already been represented in
+Fig. 118. The pressures of the feet are separated by the times of
+suspension.
+
+The fourth also represents running, but in this case more rapid and
+characterized by the shorter pressures, the slightly longer periods of
+suspension intervals, and the quicker succession of movements.
+
+Before putting aside the indications relating to the walking movements
+of man--indications which it was necessary to give in order to render
+intelligible those which are connected with the paces of the horse--we
+have yet to fix the value of that which we call 'a step.'
+
+It is generally admitted that a step is constituted by the series of
+movements which are produced between the corresponding phases of the
+action of one foot and that of the other--for example, between the
+moment at which the right foot commences its pressure on the ground and
+that at which the left foot commences its own. It is necessary to adopt
+here another method of looking at it, and to regard the preceding as
+being but a _half-step_. The step should then be defined as being
+constituted by the series of movements which are executed between two
+similar positions of the same foot--as, for example, between the
+commencement of a pressure of the right foot and the similar phase of
+the following pressure of the same foot. We shall soon understand the
+importance of this definition.
+
+Before entering on the details of the paces of the horse, it is
+necessary to see how the limbs of the latter oscillate during the period
+of a complete step; or, which is the same thing, to determine what the
+displacements are which a limb executes between two similar positions of
+its foot.
+
+If we examine one of the limbs during a forward movement of the animal,
+we see that this limb passes through two principal phases: (1) It is
+raised from the ground; (2) it resumes contact with the ground. Each of
+these phases is divided into three periods of time, which we proceed to
+analyze in connection with the anterior limb.
+
+[Illustration: FIG. 120.--SWING OF THE RAISED ANTERIOR LIMB (AFTER G.
+COLIN).[71]
+
+C, Lifting; B, suspension; A, placing.]
+
+  [71] G. Colin, 'Traite de Physiologie Comparee des Animaux,' third
+       edition, Paris, 1886.
+
+The foot quits the ground (Fig. 120, C); this may be called _lifting_;
+the limb is oblique in direction downwards and backwards. This same limb
+is flexed and carried forward (Fig. 120, B), and, as it is supported by
+the action of its flexors, this is the period named _suspension_; the
+hoof is vertical. Then the limb is carried still further forward,
+becoming extended (Fig. 120, A); the heel is lowered, and the foot,
+being oblique, is directed towards the ground; this is the _placing_.
+
+Then takes place pressure (Fig. 121). The foot has just been placed on
+the ground; the limb is oblique in direction downwards and forwards;
+this we call _commencement of the pressure_ (Fig. 121, A). Then the
+body, being carried forward, whilst the hoof, D, is fixed on the ground,
+the limb becomes vertical: this stage is _mid-pressure_ (Fig. 121, B).
+Finally, the progression of the body continuing, the limb becomes
+oblique downwards and backwards; it is now at the _termination of
+pressure_ (Fig. 121, C), and proceeds to lift itself anew if another
+step is to be made.
+
+In conclusion, the inferior extremity of the limb describes, from its
+elevation to its being placed on the ground, an arc of a circle around
+its superior extremity (Fig. 121, D); whilst, during the pressure, it is
+its superior extremity which describes one around its inferior
+extremity, then fixed on the ground (Fig. 121, D).
+
+[Illustration: FIG. 121.--SWING OF THE ANTERIOR LIMB ON THE POINT OF
+PRESSURE (AFTER G. COLIN).
+
+A, Commencement of the pressure; B, centre of the pressure; C,
+termination of the pressure.]
+
+If we simultaneously examine the two fore-limbs, we remark that when one
+of them begins its pressure the other ends it, and _vice versa_.
+
+As to the hind-limbs, the oscillations are similar to those of the fore
+ones. In the second half of the pressure--that is, when they are passing
+from the vertical direction (Fig. 122, A) to extreme obliquity backwards
+(Fig. 122, C)--the effect of their action is to give propulsion to the
+body.
+
+The fore and hind limbs make the same number of steps, and the steps
+have the same length.
+
+The limbs of any quadruped--but we make special allusion to those of
+the horse--are divided into groups in the following manner:
+
+The anterior pair constitutes the _anterior biped_. The _posterior
+biped_ is that formed by the posterior limbs.
+
+The name of _lateral biped_ serves to designate the whole formed by the
+two limbs of the same side. The right fore-limb and the right hind-limb
+form the _right lateral biped_. The two others form the _left lateral
+biped_.
+
+[Illustration: FIG. 122.--POSTERIOR LIMB, GIVING THE IMPULSE (AFTER G.
+COLIN).
+
+A, Commencement of pressure; B, centre of pressure; C, termination of
+pressure.]
+
+A fore-limb and hind-limb belonging to the opposite side form a
+_diagonal biped_, which also takes the name of the fore-limb which forms
+a part of it. Thus, _the right diagonal biped_ is formed by the
+association of the right fore-limb and the left hind one. The _left
+diagonal biped_ is, consequently, the inverse.
+
+It is necessary to remember well these preliminary indications; it is
+the only means of comprehending with facility that which is about to
+follow.
+
+Let us first return to the grouping of the limbs. The denominations
+_anterior_ and _posterior bipeds_ render clearly perceptible the
+comparison which consists in regarding a horse when walking as capable
+of being represented by two men marching one behind the other, and
+making the same number of steps. According as they move the legs of the
+same side at the same time in 'covering the step,' or march in
+contretemps step, we find reproduced all the rhythms which characterize
+the different paces of the horse.
+
+[Illustration: FIG. 123.--NOTATION OF THE AMBLING GAIT IN THE HORSE
+(AFTER PROFESSOR MAREY).]
+
+Professor Marey has studied these paces by a similar method to that
+which he adopted for the walking of man, and which we have already
+described. He employed hollow balls fixed under the hoofs, and a
+registering apparatus with four styles, each corresponding to one of the
+limbs. The tracing obtained is rather complicated, since two sets of
+lines are found marked. But a notation similar to that of which we have
+spoken can be discovered, and its exact signification should now be
+determined. For this purpose, we have selected the most simple (see Fig.
+123). We there see, placed in two superimposed lines, the pressure
+markings of the right feet (white bands), and of the left feet (gray
+bands). On the upper line are found those related to the fore-legs; the
+lower lines contain those associated with the hind-legs. It is, in
+brief, the superposition of two notations of the human walking
+movements. And seeing that, as we have previously pointed out, we may
+make a comparison between a quadruped and two men placed one behind the
+other, it is easy to understand the significance of the superimposed
+notations, if we accustom ourselves to look on them as the notations of
+two bipeds.
+
+To read these notations--that is, to learn to know what occurs at each
+of the movements of the pace--it is necessary, indeed, to remember that
+they should be examined in vertical sections; it is to each of these
+sections--of these vertical divisions--that each of the movements which
+we more particularly wish to analyze corresponds.
+
+We proceed to study first the pace of ambling, because it is the most
+simple; we shall then consider the trot, and, finally, we shall examine
+that which is the most complicated, viz., the step.
+
+[Illustration: FIG. 124.--THE AMBLE: RIGHT LATERAL PRESSURE.[72]]
+
+  [72] The figures which, in the present study, reproduce the different
+       paces, have been made from our articulated horse (see the note on
+       p. 282).
+
+=The Amble.=--To give an exact idea of the general character of the
+amble, let us fancy the two men whom we discussed above marching one
+behind the other and walking in step--that is, moving the legs of the
+same side simultaneously. They will thus represent the amble, which,
+indeed, results from the alternate displacements of the lateral bipeds;
+the limbs of the same side (right or left) execute the same movements in
+the same time.
+
+This is what the notation indicates (Fig. 123). We there see that the
+pressures of the right fore-foot, marked by the white bands in the upper
+range, are exactly superposed on those of the right hind one, which are
+marked by a similar band on the lower line; this means that the
+pressures took place in the same time. We there see also a similar
+arrangement of the gray bands, which has a similar significance for the
+left fore and hind feet.
+
+And if we recollect the three phases of pressure (see p. 289, and Figs.
+121, 122), we shall comprehend, in looking at the diagrams, that, at the
+initial stage (A), the limbs are commencing their pressure, and are
+oblique downwards and forwards; that afterwards (B) the two limbs are
+vertical, since they are at the middle of the pressure stage; and that
+finally (C) they are oblique downwards and backwards, for it is then the
+termination of their pressure (Fig. 124).
+
+[Illustration: FIG. 125.--NOTATION OF THE GAIT OF THE TROT IN THE HORSE
+(AFTER PROFESSOR MAREY).]
+
+During the time that the right limbs are pressing (notation, white
+bands) the left limbs are raised; afterwards these latter take up the
+pressure (gray bands), and then the right limbs are raised in their
+turn.
+
+During the pace of ambling the weight of the body, which is wholly
+sustained by the limbs of one side only, is not in equilibrium, so that
+the limbs which are raised return by a brisk movement to the position of
+support in order to re-establish it.
+
+=The Trot.=--We have just seen that, in order to represent the amble,
+the two marchers moved their right limbs simultaneously, and then their
+left ones.
+
+Let us suppose now that the hinder man anticipated by half a pace the
+movement of the front one, then will be found realized the association
+and the nature of the displacements of the limbs during the pace of the
+trot.
+
+By this anticipation of a half-step (we have defined, p. 288, what is to
+be understood by the word _step_), it follows that when the marcher who
+is in front advances his right leg it is the left leg of the marcher who
+follows him that is carried in the same direction. We should thus
+conclude from this that the trot is characterized by a succession of
+displacements of the diagonal bipeds.
+
+[Illustration: FIG. 126.--THE TROT; RIGHT DIAGONAL PRESSURE.]
+
+[Illustration: FIG. 127.--THE TROT; TIME OF SUSPENSION.]
+
+Indeed, if we examine the notation of this gait (Fig. 125), we see that
+with the pressure of the right fore-foot is found associated the
+pressure of the left hind-foot. It is, accordingly, a typical diagonal
+biped (Fig. 126).
+
+[Illustration: FIG. 128.--NOTATION OF THE PACE OF STEPPING IN THE HORSE
+(AFTER PROFESSOR MAREY).
+
+L, Right lateral pressure; D, right diagonal pressure; L', left lateral
+pressure; D', left diagonal pressure.]
+
+But it is necessary to add that these groups of pressures do not succeed
+one another without interruption, except in the slow trot. In the
+ordinary trot, or in that in which the animal's strides are very long,
+the body between each of the double pressures which we have just been
+considering is projected forward with such force that it remains for an
+instant separated from the ground. This is what we designate by the name
+of _time of suspension_ (Fig. 127). The notation in this case would be
+slightly different from that which we reproduce above, in this sense:
+that between the diagonal pressures there then would be found an
+interval, since during the time the body is suspended none of the feet
+can produce a pressure-mark (see, with regard to these intervals, the
+notations of the running of a man, Fig. 118, and Fig. 119, 3, 4).
+
+=The Walk.=--Although slow, a feature which would seem to make it
+possible to permit its analysis in a horse when walking, this pace is
+difficult to comprehend without sufficient preliminary study.
+
+[Illustration: FIG. 129.--THE STEP: RIGHT LATERAL PRESSURE.]
+
+[Illustration: FIG. 130.--THE STEP: RIGHT DIAGONAL PRESSURE.]
+
+We saw above that in order to represent the amble the marchers had to
+move the legs of the same side simultaneously. We have also just seen
+that in order to represent the trot the marcher at the back had to
+anticipate by a half-step. Suppose, now, that this same marcher
+anticipates the man in front by a quarter-step only, or by a
+half-pressure period, and thus will be found realized the order of
+succession of the limbs in the gait or pace called the _walk_. The feet
+meet the ground one after the other, since they are each in advance by
+half the duration of a pressure. The strokes are four in number during
+the period of a step of this pace; in the amble and in the trot they do
+not exceed two, for then the limbs strike the ground in lateral diagonal
+pairs.
+
+[Illustration: FIG. 131.--THE GALLOP: FIRST PERIOD.]
+
+[Illustration: FIG. 132.--THE GALLOP: SECOND PERIOD.]
+
+[Illustration: FIG. 133.--THE GALLOP: THIRD PERIOD.]
+
+[Illustration: FIG. 134.--THE GALLOP: TIME OF SUSPENSION.]
+
+If we examine the notation of the pace of walking (Fig. 128), we see
+that the right fore-foot commences its pressure when the right
+hind-foot is in the middle of its own, and that the hinder left begins
+in the middle of that of the right fore-foot, and that it is itself at
+the midst of its pressure when the left fore-foot touches the ground,
+etc. In a word, the foot-fallings occur in the following order and at
+regular intervals--the fore right foot is here considered as acting
+first: right fore, left hind, left fore, right hind, and so on in
+succession.
+
+[Illustration: FIG. 135.--NOTATION OF THE GALLOP DIVIDED INTO THREE
+PERIODS OF TIME (AFTER PROFESSOR MAREY).
+
+1, First period; 2, second period; 3, third period.]
+
+As to the nature of the bipeds which succeed one another, it is easy to
+understand them by means of the notation. In reading this from left to
+right, we see that the associations of pressure are first made by the
+two right feet, then by a right foot and a left one, then by two left
+feet, and, finally, by a left and right. It is, accordingly, a
+succession this time of lateral and diagonal pressures.
+
+[Illustration: FIG. 136.--NOTATION OF THE GALLOP OF FOUR PERIODS IN THE
+HORSE (AFTER PROFESSOR MAREY).
+
+1, First period; 2, second period; 3, third period; 4, fourth period.]
+
+Thus, we find at the start a right lateral pressure (Fig. 129), next a
+right diagonal (Fig. 130), then a left lateral; finally, a left diagonal
+pressure. It is thus that the initial letters L, D, L', D' further
+indicate the notations represented in Fig. 128.
+
+=The Gallop.=--The ordinary gallop is a pace of three phases. The first
+is characterized by the fact that one hind-limb alone rests on the
+ground (Fig. 131); in the second the animal is on a diagonal support
+(Fig. 132); in the third it comes down on a fore-limb (Fig. 133). The
+body is then raised (Fig. 134), and to this period of suspension succeed
+anew the three modes of pressure indicated above.
+
+The gallop is said to be from either right or left. In the gallop from
+the right, the right fore-leg is the more frequently in advance of its
+neighbour; it is the last to be placed on the ground. The left foot of
+the posterior biped is the one which commences the action.
+
+An entirely opposite arrangement characterizes the gallop from the left.
+
+[Illustration: FIG. 137.--LEAP OF THE HARE (AFTER G. COLIN).]
+
+The notation reproduced in Fig. 135 corresponds to the gallop from the
+right. It is there seen, as we pointed out above, that in the first
+phase the exclusive support of the left hind-foot takes place (1); that
+afterwards, in the second, commence simultaneously, the pressures of the
+left fore and the right hind foot (2); this is the left diagonal
+support; and that finally, in the third, the body comes down on a
+fore-limb, which is then the right (3); and that for a moment it is on
+this limb alone that the animal rests.
+
+To these three phases on the notation succeeds an interval; this is the
+period of suspension.
+
+The gallop of four phases only differs from the preceding in that the
+foot-fallings of each diagonal biped occur at slight intervals, and give
+distinct sounds. The notation is reproduced in Fig. 136.
+
+[Illustration: FIG. 138.--THE LEAP.]
+
+[Illustration: FIG. 139.--THE LEAP.]
+
+[Illustration: FIG. 140.--THE LEAP.]
+
+[Illustration: FIG. 141.--THE LEAP.]
+
+=The Leap.=--The leap is an act by which the body is wholly raised from
+the ground and projected upwards and forwards to a greater or less
+distance.
+
+It is prepared for by the flexing of the hind-limbs, which, by being
+suddenly extended, project the body, and thus enable it to pass over an
+obstacle.
+
+This preparatory arrangement is very remarkable in the leap of the lion,
+the cat, and the panther, which execute springs of great length; in the
+horse, in which the leap is not an habitual mode of progression, this
+flexion of the hinder limbs is less marked. With this animal the leap is
+generally associated with the gallop; nevertheless, it is sometimes made
+from a stationary position. In observing the hare or the rabbit, in
+which the leap is habitual, we notice (Fig. 137) that the hind-limbs,
+being extremely flexed, rest on the ground as far as the calcaneum, are
+then straightened by the action of their extensors, become vertical and
+then oblique backwards at the moment the body is thrown forward into
+space by the sudden extension of these limbs.
+
+The action of the extensors is energetic and instantaneous, and their
+energy is greater than in ordinary progression, for it is required to
+lift the body and to project it forcibly a more or less considerable
+distance. It is the extreme rapidity of this action which enables the
+animal to clear an obstacle, for without this condition the body would
+be raised, but not separated from the ground.
+
+First of all, in reaching the obstacle to be cleared, the horse prepares
+to leap by taking the attitude of rearing; the hind-limbs are flexed and
+carried under the body, the fore-quarters are raised, and the different
+segments of the fore-limbs are flexed (Fig. 138).
+
+[Illustration: FIG. 142.--THE LEAP.]
+
+[Illustration: FIG. 143.--THE LEAP.]
+
+One sudden trigger action produced by the violent contraction of the
+extensors of the hind-legs then takes place, and the animal is projected
+forwards, while he flexes the fore-legs more and more (Fig. 139). He
+has then risen above the obstacle (Fig. 140). Then while he makes the
+downward and forward balancing movement, and points his fore-limbs in
+the same direction, he flexes the hind ones (Fig. 141). Whilst the
+latter are further flexed, in order to pass the obstacle in their turn,
+the fore-limbs which are extended come into contact with the ground
+(Fig. 142). Finally, in the last phase of the leap, the animal, raising
+himself in front, after the impact of his hind-feet has taken place
+(Fig. 143), prepares to continue the pace at which he progressed before
+meeting the obstacle which he had to clear.
+
+
+THE END
+
+
+_London: Bailliere, Tindall and Cox, 8, Henrietta Street, Covent Garden,
+W.C._
+
+
+
+
+  THE
+  ARTISTIC ANATOMY OF ANIMALS
+
+[Illustration]
+
+
+
+
+SECTIONAL INDEX
+
+
+                                                                   PAGE
+
+  =Generalities of Comparative Anatomy=                               1
+
+
+  OSTEOLOGY AND ARTHROLOGY
+
+  =The Trunk:=
+    _Vertebral Column_                                                4
+      Sacrum                                                         10
+      Coccygeal vertebrae                                             11
+      Direction and form of the vertebral column                     11
+    _Thorax_                                                         12
+      Sternum                                                        14
+      Ribs and costal cartilages                                     14
+
+  =The Anterior Limbs:=
+    _Shoulder_                                                       20
+      Scapula                                                        21
+      Clavicle                                                       25
+    _Arm_                                                            28
+      Humerus                                                        28
+    General view of the form of the forearm and hand                 34
+      Forearm                                                        38
+      Hand                                                           44
+
+  =The Anterior Limbs in Certain Animals:=
+    _Plantigrades_: Bear                                             49
+    _Digitigrades_: Cat, dog                                         51
+    _Unguligrades_: Pig                                              57
+      Sheep, Ox                                                      60
+      Horse                                                          64
+    Proportions of the arm, the forearm, and metacarpus              70
+    Articulations of the anterior limbs                              71
+      Scapulo-humeral articulation                                   72
+      Humero-ulnar articulation, or elbow                            74
+      Radio-ulnar articulation                                       75
+      Articulation of the wrist                                      75
+      Metacarpo-phalangeal articulations                             76
+      Interphalangeal articulations                                  77
+
+  =The Posterior Limbs:=
+    _Pelvis_                                                         78
+      Iliac bone                                                     78
+    _The Thigh_                                                      83
+      Femur                                                          83
+      Knee-cap                                                       85
+    _The Leg_                                                        85
+      Tibia                                                          86
+      Fibula                                                         87
+    _The Foot_                                                       87
+
+  =The Posterior Limbs in Some Animals:=
+    _Plantigrades_: Bear                                             90
+    _Digitigrades_: Cat, dog                                         91
+    _Unguligrades_: Pig                                              94
+      Sheep, ox                                                      95
+      Horse                                                          99
+    Articulations of the posterior limbs                            105
+      Coxo-femoral articulation                                     105
+      Femoro-tibial articulation, or knee                           106
+      Tibio-tarsal articulation, and of the bones of the tarsus     107
+
+  =The Head in General, and in Some Animals in Particular:=
+    Direction of the head                                           109
+    The skull                                                       112
+    The face                                                        118
+    The skull of birds                                              127
+
+
+  MYOLOGY
+
+  =Muscles of the Trunk:=
+    Pectoralis major                                                131
+    Pectoralis minor                                                133
+    Serratus magnus                                                 134
+
+  =Muscles of the Abdomen:=
+    External oblique                                                136
+    Internal oblique                                                137
+    Transversalis abdominis                                         138
+    Rectus abdominis                                                138
+    Pyramidalis abdominis                                           139
+
+  =Muscles of the Back:=
+    Trapezius                                                       140
+    Latissimus dorsi                                                142
+    Rhomboid                                                        144
+
+  =The Cutaneous Muscle of the Trunk=                               147
+
+  =The Coccygeal Region:=
+    Ischio-coccygeal muscle                                         149
+    Superior sacro-coccygeal muscle                                 150
+    Lateral sacro-coccygeal muscle                                  150
+    Inferior sacro-coccygeal muscle                                 150
+
+  =Muscles of the Neck:=
+    Mastoido-humeralis                                              150
+    Sterno-mastoid                                                  153
+    Omo-trachelian                                                  155
+    Levator anguli scapulae                                          156
+    Splenius                                                        158
+
+  =Infrahyoid Muscles:=
+    Sterno-thyroid and sterno-hyoid                                 160
+    Omo-hyoid                                                       160
+
+  =Suprahyoid Muscles:=
+    Mylo-hyoid                                                      161
+    Digastric                                                       161
+
+  =Panniculus of the Neck=                                          162
+
+  =Muscles of the Anterior Limbs:=
+    _Muscles of the Shoulder_                                       162
+      Deltoid                                                       162
+      Subscapularis                                                 163
+      Supraspinatus                                                 164
+      Infraspinatus                                                 165
+      Teres minor                                                   166
+      Teres major                                                   166
+      Panniculus muscle of the shoulder                             167
+    _Muscles of the Arm_                                            168
+      Anterior region                                               169
+        Biceps                                                      169
+        Brachialis anticus                                          170
+        Coraco-brachialis                                           170
+      Posterior region                                              171
+        Triceps                                                     171
+      _Supplemental or Accessory Muscle of the Latissimus Dorsi_    173
+    _Muscles of the Forearm_                                        174
+      Anterior and external region                                  176
+        Supinator longus                                            176
+        First and second external radial                            176
+        Supinator brevis                                            179
+        Extensor communis digitorum                                 179
+        Extensor minimi digiti                                      183
+        Posterior ulnar                                             185
+        Anconeus                                                    185
+        Long abductor of the thumb                                  186
+        Short extensor of the thumb                                 187
+        Long extensor of the thumb                                  187
+        Proper extensor of the index                                187
+      Internal and posterior region                                 188
+        Pronator teres                                              188
+        Flexor carpi radialis                                       189
+        Palmaris longus                                             189
+        Anterior ulnar                                              191
+        Superficial flexor of the digits                            193
+        Long proper flexor of the thumb                             197
+        Pronator quadratus                                          198
+    _Muscles of the Hand_                                           199
+
+  =Muscles of the Posterior Limbs:=
+    _Muscles of the Pelvis_                                         200
+      Gluteus medius                                                200
+      Gluteus maximus                                               201
+    _Muscles of the Thigh_                                          204
+      Muscles of the posterior region                               205
+        Biceps                                                      205
+        Semi-tendinosus                                             206
+        Semi-membranosus                                            207
+      Muscles of the anterior region                                210
+        Triceps                                                     210
+        Tensor fascia lata                                          211
+        Sartorius                                                   211
+      Muscles of the internal region                                213
+        Gracilis                                                    213
+    _Muscles of the Leg_                                            213
+      Muscles of the anterior region                                214
+        Tibialis anticus                                            214
+        Extensor proprius pollicis                                  219
+        Extensor longus digitorum                                   219
+        Peroneus tertius                                            224
+      Muscles of the external region                                224
+        Peroneus longus                                             224
+        Peroneus brevis                                             225
+      Muscles of the posterior region                               227
+        Gastrocnemius                                               227
+        Soleus                                                      228
+        Plantaris                                                   228
+        Popliteus                                                   228
+        Superficial flexor of the toes                              229
+        Flexor longus digitorum                                     230
+        Tibialis posticus                                           230
+        Flexor longus pollicis                                      231
+    _Muscles of the Foot_                                           231
+        Dorsalis pedis                                              231
+    _Muscles of the Head_                                           232
+      Masticatory muscles                                           232
+      Masseter                                                      232
+      Temporal muscle                                               234
+      Cutaneous muscles of the head                                 234
+        Occipito-frontalis                                          234
+        Orbicularis palpebrarum                                     234
+        Pyramidalis nasi                                            235
+        Corrugator supercilii                                       235
+        Zygomaticus major                                           235
+        Zygomaticus minor                                           236
+        Levator labii superioris proprius                           237
+        Levator labii superioris alaeque nasi                        238
+        Transversus nasi                                            239
+        Caninus                                                     239
+        Orbicularis oris                                            240
+        Triangularis oris                                           240
+        Quadratus menti                                             240
+        Prominence of the chin                                      240
+        Buccinator                                                  241
+          Maxillo-labialis                                          242
+        Zygomatico-auricularis                                      242
+        Temporo-auricularis externus                                243
+        Scuto-auricularis externus                                  243
+        Cervico-auricular muscles                                   243
+        Cervico-auricularis superioris                              244
+        Cervico-auricularis medius                                  244
+        Cervico-auricularis inferioris                              244
+        Parotido-auricularis                                        244
+        Temporo-auricularis internus                                244
+        Zygomatico-auricularis                                      245
+
+
+  EPIDERMIC PRODUCTS OF THE TERMINAL EXTREMITIES OF THE FORE AND
+  HIND LIMBS
+
+  Claws                                                             247
+  Plantar tubercles                                                 248
+  Hoofs of the solipeds                                             250
+  Hoofs of ox and pig                                               261
+
+         *       *       *       *       *
+
+  Proportions                                                       262
+  Proportions of head of horse                                      273
+    (front view)                                                    276
+
+  Paces of the horse                                                282
+    Amble                                                           293
+    Trot                                                            294
+    Walk                                                            296
+    Gallop                                                          300
+    Leap                                                            364
+
+
+
+
+ERRATA
+
+
+P. 105, _Articulations_ of the Posterior Limbs.
+
+P. 107, Tibio-tarsal _Articulation_.
+
+
+
+
+THE END
+
+
+_London: Bailliere, Tindall and Cox, 8, Henrietta Street, Covent Garden,
+W.C._
+
+
+
+
+  +--------------------------------------------------------------------+
+  |                       TRANSCRIBER'S NOTES:                         |
+  |                                                                    |
+  | Footnotes have been moved to underneath the paragraph, table or    |
+  | illustration they refer to.                                        |
+  |                                                                    |
+  | Illustrations have been moved so as to not disrupt the flow of the |
+  | text. Page numbers in the List of Illustrations and in references  |
+  | have not been changed, and are therefore not always correct.       |
+  |                                                                    |
+  | The Table of Contents and the Sectional Index are not complete and |
+  | contain slightly different wording than the names of sections in   |
+  | the text. This has been left as in the original work.              |
+  |                                                                    |
+  | The Errata have already been changed in the text.                  |
+  |                                                                    |
+  | The author uses the terms chromophotograph and chronophotograph    |
+  | (and derivations of these words); these words have not been        |
+  | changed. The correct term in these cases is chronophotograph.      |
+  |                                                                    |
+  | Page 143, Fig. 69: atlas is mentioned twice (nrs. 12 and 13); only |
+  | nr. 13 indicates the atlas.                                        |
+  |                                                                    |
+  | The text used is that of the original work, including              |
+  | inconsistencies in spelling, hyphenation and lay-out, and          |
+  | differences between main text, footnotes and captions, except when |
+  | mentioned below.                                                   |
+  |                                                                    |
+  | Changes made to the text:                                          |
+  |   Some minor obvious typographical errors have been corrected      |
+  |   silently.                                                        |
+  |   Periods have been removed from some section headings for         |
+  |   consistency.                                                     |
+  |   Page 2, footnote [2]: Mathias-Duval changed to Mathias Duval     |
+  |   (full name: Mathias-Marie Duval).                                |
+  |   Page 23: _see_ replaced with see for consistency.                |
+  |   Page 44 (footnote 12): Edward Cuyer changed to Edouard Cuyer as  |
+  |   elsewhere.                                                       |
+  |   Page 53, captions (2x): AA^1 changed to AA' as in drawing and    |
+  |   text.                                                            |
+  |   Page 120, Fig. 63, caption: 14', malar bone added, 14 changed to |
+  |   anterior orifice of the cavity of the nasal fossae (as in previous|
+  |   figures).                                                        |
+  |   Page 216: tendo-Achilles changed to tendo-Achillis as elsewhere. |
+  |   Page 234: Fig. 0, 92 changed to Fig. 90, 2.                      |
+  |   Page 254, Fig. 98: epternal changed to external.                 |
+  |   Page 269, last paragraph: one anchor to same footnote deleted.   |
+  |   Page 325: L, D, L', D' changed to L, D, L', D'.                  |
+  |   Footnotes 13, 17: La Natura changed to La Nature.                |
+  +--------------------------------------------------------------------+
+
+
+
+
+
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