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+*** START OF THE PROJECT GUTENBERG EBOOK 77743 ***
+
+
+
+
+                           DUVAL’S ARTISTIC
+                               ANATOMY.
+
+                          Completely Revised
+                with additional Original Illustrations.
+                        Edited and Amplified by
+
+                      A. MELVILLE PATERSON, M.D.
+
+    LATE DERBY PROFESSOR OF ANATOMY IN THE UNIVERSITY OF LIVERPOOL
+
+  [Illustration]
+
+                        FUNK & WAGNALLS COMPANY
+                          New York and London
+
+
+
+
+    First published _September_ 1884
+    _Reprinted_ 1885, 1888, 1890, 1891, 1892, 1894, 1896, 1898, 1899,
+      1901, 1903, 1904
+    Revised and Enlarged Edition 1905. _Reprinted_ 1907, 1911, 1914,
+      1916, 1919
+
+
+
+
+                    PREFACE TO THE REVISED EDITION
+
+
+Few words of preface are needed here. The preface of the original
+edition still holds good, and sufficiently defines the aims and scope
+of the book. The first object aimed at is to facilitate the study of
+artistic anatomy by the demonstration of the meaning of the appearances
+presented by the various parts of the body. Incidentally it is hoped
+that through close study the powers of observation will be quickened.
+By a simple narration of the structure of the body and its mechanism,
+particularly in relation to surface forms, it is hoped that the student
+of art may correctly and intelligently appreciate the why and wherefore
+of the parts which he is called upon to paint or model.
+
+One would reiterate and emphasise the necessity of two additional
+aids to this end. In his studies the student should have and use the
+opportunity of seeing and handling the separate bones and also an
+articulated skeleton; and where possible, he should have access to a
+fully equipped anatomical museum. He should further take advantage
+of all means of studying on the living model--on himself, on other
+models--and in casts, the movements, attitudes, and gestures of the
+body, and the resulting surface forms. By these two studies it becomes
+possible to correlate properly the superficial appearances with the
+deeper structures, such as bones, joints, and muscles, which are mainly
+responsible for the characteristic features presented in the living
+state.
+
+I have to express my indebtedness to my friend Dr. Thurstan Holland
+for the radiograph (Fig. 25, p. 80) specially prepared by him for this
+work; and to the publisher of Cunningham’s Text Book of Anatomy for
+permission to use the figure (p. 315) of the muscles of expression.
+
+                                                           A. M. P.
+
+_Liverpool_, _July_, 1905.
+
+
+
+
+                           AUTHOR’S PREFACE
+
+
+This little work is an epitome of a course of lectures which for about
+ten years I had the honour of delivering at the École des Beaux-Arts.
+If during that time I have arrived at a right understanding of the
+teachings of anatomy, I owe it to the great interest taken in the
+subject by my listeners of all ages; and my first duty is to thank
+them for their free interchange of ideas with me, thus enabling me
+to understand their requirements and the mode of satisfying them.
+But if the mode of exposition I have adopted is to be rendered clear
+to a constantly renewed audience, I must, in publishing this work,
+first explain to the reader how the lectures are to be used, and the
+principles which guided me in their production.
+
+This summary of anatomy is intended for those artists who, having
+commenced their special studies, have drawn the human form either from
+the antique or from the living model--who, in a word, have already what
+may be termed a general idea of forms, attitudes, and movements. It
+is intended to furnish them with a scientific notion of those forms,
+attitudes, and movements. Thus it is far less a description of the
+forms of a particular region than the anatomical explanation of those
+forms, and of their modifications in a state of repose or movement,
+that we have in view. That is why, instead of proceeding from the
+surface to the deeper organs and to the skeleton, we take the latter as
+the starting-point of our studies. In this way alone can we determine
+the laws which govern the movements of the adjacent segments of the
+limbs upon each other, and the movements of the limbs with regard to
+the trunk, as also the reciprocal action of these segments towards each
+other and in relation to the whole body.
+
+When to these fundamental notions is added a knowledge of the muscular
+masses which move these bones, the artist will at once be enabled to
+analyse through the skin, as through a transparent veil, the action of
+the parts which produce the various forms with their infinite variety
+of character and movement.
+
+This method of teaching, which may be said to proceed by synthesis,
+differs from that followed by the generality of works on this
+subject--books which treat by analysis. We make special allusion to the
+treatise of Gerdy,[1] which is about the most careful work on plastic
+anatomy yet published, but which errs in a somewhat too lengthy
+description of external form, whilst sufficient space is not devoted
+to explaining the anatomical reasons of those forms. On the other
+hand, the remaining anatomical works in the hands of the students in
+our art schools generally comprise a volume of text and an illustrated
+atlas.[2] Under these conditions, may I be allowed to remark, somewhat
+severely, it may be, that our young artists study the atlas by copying
+and re-copying the plates, but do not read the text? Thus it will be
+understood why, in this work, a different method has been pursued;
+and the fact of the plates being intermixed with the text, and in
+such a way that they cannot well be understood without the aid of the
+accompanying pages, will in all probability result in the student
+thoroughly and carefully perusing the text.
+
+Passing on to the manner of using the present work, we must acknowledge
+that reading anatomical details is at first dry; it will always be
+so, unless proceeded with in a simple and systematic manner. In the
+oral courses, the lecturer, handling the objects, and aided by his
+improvised drawings on the blackboard, can make the most complex parts
+interesting; and by adroit repetitions and varied illustrations, fix
+the attention and render the subject comprehensible, whereas it is
+quite different in a written description. In this case it is the reader
+who must animate the text for himself by examining and manipulating the
+parts needful for the elucidation of the descriptions. For this purpose
+a skeleton and a good plaster cast will suffice. On the cast, with the
+aid of the plates which accompany the text, it will be easy to follow
+the course of the muscles; and in this way alone will the study of them
+become profitable, the student being enabled to examine the model on
+different sides. By handling the bones, by placing the articulating
+surfaces in contact, the dry descriptions of the mechanism of the
+joints will take a tangible form, and will henceforth remain impressed
+on the memory. For example, notwithstanding our diagrams of the
+movements of pronation and supination, it is only by handling the bones
+of the forearm that the student will be enabled to fully appreciate the
+marvellous mechanism by which the rotation of the radius round the ulna
+is effected, allowing the hand to present alternately its palmar and
+dorsal surface; and the same is the case in regard to the skeleton of
+the foot and head, and the movements of the lower jaw, &c.
+
+The artist will find in this book some pages devoted to the
+_facial angle_, to the forms of the head, _brachycephalic_ and
+_dolichocephalic_ heads, and to some other questions of anthropology,
+and will doubtless thank us for having considered here ideas which are
+daily becoming familiar to the general public.
+
+Our only regret concerning these anthropological studies is that the
+limits of this volume did not permit us to go deeper into the teachings
+of the anthropological laboratory, the direction of which was confided
+to me after the loss of our illustrious master, Broca.
+
+I take this opportunity of expressing my gratitude to my excellent
+master, Professor Sappey, who allowed me to borrow from his
+magnificent treatise on anatomy the figures on osteology and myology
+which constitute the chief merit of this work; and to my friend and
+colleague, E. Cuyer, whose skilful pencil reproduced the figures from
+the photographic atlas of Duchenne, as well as the two illustrations of
+the Gladiator, and the sundry diagrammatic drawings which complete the
+theoretical explanations of the text.
+
+                                                          M. DUVAL.
+
+
+
+
+                               CONTENTS
+
+
+    CHAPTER                                                        PAGE
+
+        I. INTRODUCTION TO THE REVISED EDITION                        1
+
+       II. INTRODUCTION.--PLASTIC ANATOMY: ITS HISTORY,
+             IMPORTANCE, AND OBJECTS--ORDER OF THESE
+             STUDIES--DIVISION OF SUBJECT                             7
+
+
+               First Part.--THE SKELETON, ARTICULATIONS,
+                             PROPORTIONS.
+
+      III. OSTEOLOGY AND ARTHROLOGY IN GENERAL--NOMENCLATURE
+             --VERTEBRAL COLUMN                                      19
+
+       IV. SKELETON OF THE TRUNK (THORAX)--STERNUM--RIBS--THORAX
+             AS A WHOLE                                              41
+
+        V. SKELETON OF SHOULDER--CLAVICLE--SCAPULA--HEAD
+             OF HUMERUS--SHOULDER JOINT                              55
+
+       VI. HUMERUS AND ELBOW JOINT                                   67
+
+      VII. SKELETON OF FORE-ARM--RADIUS AND ULNA--MOVEMENTS
+             OF PRONATION AND SUPINATION                             77
+
+     VIII. SKELETON OF THE HAND--WRIST (CARPUS)--HAND AND
+             FINGERS (METACARPAL BONES AND PHALANGES)--PROPORTIONS
+             OF THE UPPER LIMB--EGYPTIAN CANON--BRACHIAL INDEX       87
+
+       IX. SKELETON OF THE HIPS--PELVIS (ILIAC BONES AND
+             SACRUM)--THE PELVIS ACCORDING TO SEX                   103
+
+        X. THE FEMUR AND THE ARTICULATIONS OF THE HIPS--PROPORTIONS
+             OF THE HIPS AND SHOULDERS                              116
+
+       XI. THE FEMUR AND THE ARTICULATION OF THE KNEE JOINT;
+             THE SHAPE OF THE REGION OF THE KNEE                    131
+
+      XII. SKELETON OF THE LEG: TIBIA AND FIBULA, THE MALLEOLI
+             OR ANKLES--GENERAL VIEW OF THE SKELETON OF THE FOOT;
+             TIBIO-TARSAL ARTICULATION                              146
+
+     XIII. SKELETON OF THE FOOT; TARSUS; METATARSUS; TOES AND
+             FINGERS--PROPORTIONS OF THE LOWER LIMB--THE FOOT
+             AS A COMMON MEASURE                                    155
+
+      XIV. SKELETON OF THE HEAD: SKULL (OCCIPITAL, PARIETAL,
+             FRONTAL, TEMPORAL BONES); SHAPES OF THE SKULL
+             (DOLICOCEPHALIC AND BRACHYCEPHALIC HEADS)              164
+
+       XV. SKELETON OF THE FACE: THE ORBITAL CAVITIES; LOWER
+             JAW; TEETH; FACIAL ANGLE OF CAMPER                     173
+
+
+                        Second Part.--MYOLOGY.
+
+      XVI. OF THE MUSCLES IN GENERAL--MUSCLES OF THE TRUNK:
+             ANTERIOR REGION (PECTORALIS MAJOR; THE OBLIQUE
+             AND RECTI MUSCLES OF THE ABDOMEN)                      189
+
+     XVII. MUSCLES OF THE BACK: TRAPEZIUS, LATISSIMUS DORSI,
+             AND TERES MAJOR MUSCLES                                205
+
+    XVIII. MUSCLES OF THE SHOULDER: DELTOID: SERRATUS MAGNUS;
+             THE HOLLOW AND SHAPE OF THE ARM-PIT                    215
+
+      XIX. MUSCLES OF THE ARM: BICEPS; CORACO-BRACHIALIS:
+             BRACHIALIS ANTICUS; TRICEPS; SHAPE OF THE ARM          224
+
+       XX. MUSCLES OF THE FORE-ARM AND HAND: THE ANTERIOR,
+             EXTERNAL, AND POSTERIOR SUPERFICIAL MUSCLES            232
+
+      XXI. MUSCLES OF THE FORE-ARM AND HAND (_continued_):
+             THE DEEP POSTERIOR MUSCLES OF THE FORE-ARM
+             (ANATOMICAL SNUFF-BOX); MUSCLES OF THE HAND            244
+
+     XXII. MUSCLES OF THE PELVIS; THE GLUTEAL MUSCLES; FASCIA
+             LATA; MUSCLES OF THE THIGH; SARTORIUS, QUADRICEPS,
+             ADDUCTORS, &C.                                         252
+
+    XXIII. MUSCLES OF THE LEG; TENDO ACHILLIS; MUSCLES OF THE
+             FOOT                                                   268
+
+     XXIV. MUSCLES OF THE NECK: STERNO-CLEIDO-MASTOID,
+             INFRA-HYOID, AND SUPRA-HYOID MUSCLES                   281
+
+      XXV. MUSCLES OF THE HEAD; MUSCLES OF MASTICATION; MUSCLES
+             OF EXPRESSION: HISTORY (LEONARDO DA VINCI; HUMBERT
+             DE SUPERVILLE; DUCHENNE OF BOULOGNE, AND DARWIN)       291
+
+     XXVI. MUSCLES OF EXPRESSION; POSSIBLE AND IMPOSSIBLE
+             COMBINATIONS OF CERTAIN CONTRACTIONS OF THE MUSCLES
+             OF THE FACE                                            310
+
+
+
+
+                                DUVAL’S
+                           ARTISTIC ANATOMY
+
+
+
+
+                           ARTISTIC ANATOMY
+
+
+
+
+                              CHAPTER I.
+
+                 INTRODUCTION TO THE REVISED EDITION.
+
+
+In offering instruction in anatomy to artists, one feels compelled
+at the outset to attempt an answer to the question: Of what use is
+anatomy, scientifically considered, in the training of the artist?
+
+The artist requires to know his technique, just as an architect or an
+engineer needs to start with a knowledge of his materials.
+
+Looking backward, we see that science and art have ever progressed side
+by side. The history of Egypt, of Greece, of the Renaissance, shows
+glorious traditions of art, along with a full development of learning
+and philosophy. The advancement of science and of art has always
+occurred simultaneously, and there never has been a time when they have
+been divorced from one another.
+
+This is _par excellence_ the age of technical education. There
+is no questioning the importance of science, or the aid the arts
+have received from it. We see it in architecture, in the influence
+of terra-cotta and steel frames; and in art, in the introduction of
+aniline colours.
+
+Painting and sculpture are the earliest of the arts, and have produced
+some of the most cherished monuments of history; and originally the
+chief object portrayed was the human form, in action or repose.
+
+Let us for a moment consider to what extent art has been indebted to
+anatomy in the production of the masterpieces of the past.
+
+1. EGYPT.--Egypt presents the first great School of Art, as of letters
+and philosophy, and from Egypt knowledge and culture flowed to Greece
+and Italy.
+
+The vestiges of Egyptian art extant to-day comprise for the most part
+statues--some of them portraits--coins, sculpture (in low relief),
+and flat, painted outlines. As a rule, the representations of the
+human form pretend to no exact representation of detail of form
+or expression, and for the most part are executed in a formal and
+stereotyped fashion.
+
+The amount of anatomical knowledge demanded by the art of Egypt could
+obviously be acquired by direct observation of the nude or semi-nude
+figures of the living. The history of Egypt, profoundly interesting
+from all points of view, is of special interest to the anatomist, and
+centres round the mode of treatment of the dead.
+
+Ascribed usually to a belief in the immortality of the soul, the
+ceremonial treatment of the body after death was elaborate, and
+essentially religious. The body was regarded as sacred, and the
+process of embalming was a religious rite, entrusted to a band of
+the priesthood--Charhebs or Paraschistes--and no greater detail of
+anatomical examination was permitted than was deemed necessary for
+the proper preservation of the body. This band of the priesthood was
+moreover shunned and outcast, and yet with all these disadvantages some
+knowledge of anatomical structure must have been obtained.
+
+It was only later, when Greek influence became felt, that a study
+of anatomy arose in the Medical School of Alexandria. Egypt was the
+nursing mother of medical teaching, and Alexandria was the first
+great medical school. Erasistratus (B.C. 285) was the first
+great anatomist, and he utilised condemned criminals for dissection.
+Herophilus, a Jew, is said to have dissected 600 bodies.
+
+2. GREECE AND ROME.--The historical importance of Egyptian art and the
+Alexandrine School of Anatomy lies in the influence which they exerted
+upon the culture of Greece and Italy.
+
+Science and art were introduced directly into Greece and Italy
+from Egypt. Anatomical knowledge in Greece begins with Hippocrates
+(B.C. 400), who studied in Egypt under Democritus of Abdara.
+Galen, later (A.D. 131), the great Roman physician, was a
+Greek by birth, and was taught his anatomy by Heraclianus at
+Alexandria.
+
+Art in those days had ideals. Its aims were the perpetuation of the
+godlike, the heroic, the representation of perfect beauty and manly
+strength. Every reproduction was required to be, if possible, more
+beautiful than the original--virtually, as Lessing says, a law against
+caricature. “By no people,” says Winckelmann, “was beauty so highly
+esteemed as by the Greeks.”
+
+Moreover, the Greek artist was surrounded by a crowd of witnesses,
+in the masterpieces of sculpture, and in the living active forms
+of perfect manhood and womanhood. In the games there were ample
+opportunities for the study of the nude; and every evanescent, subtle
+movement could be noticed of the lithe and supple frame of the athlete.
+
+Marked attention was given to physical culture; clothing was light,
+movements free, so that the environment was perfect for the purposes of
+the sculptor or figure-painter. Prizes were given for beauty, and the
+artists were the judges.
+
+The work of the artistic anatomist of those days was superficial in a
+double sense. Cremation was the usual mode of burial, the anatomist
+dissected apes, and beyond an occasional opportunity of handling human
+bones, little exact anatomical knowledge was available. But from the
+artist’s point of view all the anatomy they needed was before their
+eyes. The best models procurable were before them; and an art that in
+some respects is perfect owes nothing to the science of anatomy.
+
+3. THE ART OF THE RENAISSANCE.--Egyptian art shows knowledge of form;
+Greco-Roman art, knowledge of form and proportion; the art of the
+Renaissance reaches a higher platform, in its portrayal of movement and
+the expression of emotion.
+
+Three factors combined to give the impetus to art at the time of the
+revival of learning. In 1315 Mondino di Luzzi made the first public
+demonstration of the anatomy of the human body. In 1400–1420 the
+process of wood-engraving, and subsequently the art of printing, were
+invented. Linked with these two facts, and with the general advance
+of learning, science, and art, was the great religious revival of
+that period. The religious sentiment gave the keynote to the artistic
+pre-eminence of the old masters. Their themes were great, and the
+result was a grandeur and a power that no merely decorative or
+realistic school can ever attain.
+
+In the 15th and 16th centuries, artists and anatomists are constantly
+found in association as fellow-workers and as personal friends. The
+great work of Andreas Vesalius on Anatomy was illustrated in an
+exact and artistic manner by Jan van Calcker, Titian’s favourite
+pupil. Leonardo da Vinci and Della Torre; Michael Angelo and Colombo;
+Benvenuto Cellini and Da Carpi; and other names might be cited to show
+the close relations of the artists and anatomists of those days.
+
+There is little doubt that the old masters seized every opportunity of
+becoming acquainted with anatomical structure. Vasari used to advise
+his pupils to study “the antique, the nude, and dissections from
+nature.” Michael Angelo was in the habit of first sketching his figures
+in the nude condition, and afterwards clothing them with the necessary
+drapery. Leonardo da Vinci has left few complete pictures; but there
+are numerous sketches in existence (notably at Milan) in which he has
+drawn with precision, dissections--_e.g._, of the knee joint, with
+bones, ligaments, and muscles in proper position. Ruskin says of him:
+“We have in this great master a proof of the manner in which genius
+submits to labour in order to attain perfection.”
+
+4. MODERN ART.--For many reasons modern art is more dependent
+than ever upon anatomical knowledge. Not to dwell upon the ennobling
+power of religious feeling--notably absent from modern art--the artist
+of the present day suffers from the plutocratic conditions of modern
+life, the inartistic fashions of modern dress, and the difficulty of
+obtaining accurate and well-formed human models; and is compelled to
+depend more and more upon a scientific knowledge of anatomy.
+
+Among the old masters there is often an excessive exhibition of
+anatomical structure, and this is liable to occur even more in some of
+the work of modern artists. A little knowledge is a dangerous thing;
+and it is of supreme importance that the anatomical knowledge used
+by the painter or sculptor should be properly applied, so that form,
+proportion, contour, and expression may all have equal value.
+
+It is too common, unfortunately, for present-day models to be
+disproportionate in form and deficient in muscular development, and the
+mistakes of nature are too often reproduced, in the form of defects or
+exaggerations, in modern sculpture and pictures. The student should
+seize every opportunity of studying the well-developed living nude form
+in action in order to obtain an adequate idea of the pattern which he
+desires to copy.
+
+
+
+
+                              CHAPTER II.
+
+                             INTRODUCTION.
+
+   Anatomy in general; the anatomy of the external forms of man;
+   physiology of the same.--Origin of the knowledge of the Greek
+   artists of the anatomy of external forms; the influence of
+   gymnastics upon Greek art.--The Renaissance and anatomical
+   study: Mondino di Luzzi (1316).--The anatomical studies of
+   Leonardo da Vinci, Michael Angelo, and Raphael.--Titian
+   and Andreas Vesalius.--The anatomical course of the School
+   of Painting (1648).--What the artist requires in the study
+   of anatomy: proportions, forms (or contours), attitudes,
+   movements.--The order of these studies; divisions of the subject.
+
+
+Anatomy, as the derivation of the word indicates (from _ἀνὰ_, across,
+and _τομὴ_, section), is the study of the parts composing the
+body--muscles, bones, tendons, ligaments, various viscera, &c.--parts
+which we separate one from the other by dissection, in order to examine
+their shapes and their relations and connections.
+
+This study may be accomplished in various ways: (1) from a
+philosophical and comparative point of view, by seeking the analogies
+and differences that the organs present in animals of different
+species--which is called _Comparative Anatomy_; (2) from a practical
+point of view, by seeking out the arrangement of organs, the knowledge
+of which is indispensable to the physician and surgeon--this is called
+_Surgical_ or _Topographical Anatomy_; (3) by examining the nature and
+arrangement of the organs which determine the external forms of the
+body--this is _Plastic Anatomy_, called also the _Anatomy of External
+Forms_, the _Anatomy of Artists_. It is the anatomy of external forms
+that we shall study here; but the artist ought to know not only the
+form of the body in repose, or in the dead subject, but also the
+principal changes of form in the body when in a state of activity,
+of movement, and of function, and should understand the causes which
+determine these changes. Plastic anatomy ought to be supplemented by
+a certain amount of knowledge of the functions of the organs, _e.g._,
+muscles and articulations; so that under the title of anatomy of the
+external forms of man we shall study at the same time the anatomy and
+the physiology of the organs which determine these forms. We should be
+contending for what has been long since conceded, were we to endeavour
+to show to what an extent the studies of anatomy and physiology are
+indispensable to the artist, who seeks to represent the human form
+under many and various types of action. Nevertheless, it may be useful
+to explain how the _chefs-d’œuvre_ of ancient art have been produced
+with admirable anatomical exactness by men who certainly had not gone
+through any anatomical studies, and to show what special conditions
+aided them to acquire, by constant practice, the knowledge that we are
+obliged to seek day by day in the study of anatomy.
+
+The Greek sculptors have reproduced the human form with marvellous
+anatomical exactness; in fact, the works of Phidias (the _Theseus_
+and the _Ilissus_), those of Myron (the _Discobolus_), those of
+Lysippus and of Praxiteles (the _Sleeping Fawn_), those of Agasias
+(the _Fighting Gladiator_), and other masterpieces given as models
+in all the schools of art, are such that it is impossible to find
+fault with them, or to discover in them the least inexactitude, either
+from an anatomical or a physiological point of view;[3] in fact, not
+only are the muscles, for example, prominent exactly in their places,
+but, more than that, these prominences are differently accentuated
+in corresponding muscles on the different sides, according to the
+nature of the movement; one side will present the muscles swelled
+up in a state of contraction, or the muscles may be in repose--that
+is, relaxed and relatively flattened. At the time when these works
+of art were produced, the study of anatomy, or even the dissection
+of the human body, had not yet been attempted; the respect in which
+the dead body was held was such that the physicians themselves, who
+should have been able to justify their motives for this study, had
+never as yet dissected a human body. In order to supply this want of
+direct knowledge Hippocrates had dissected animals, and had arrived
+at certain conclusions by the analogy that exists between the organs
+of quadrupeds and those in man. Galen himself dissected monkeys
+only, seeking to confine his examination to animals whose anatomical
+construction might be considered as most closely resembling that of
+man. Galen never possessed a human skeleton, for in a passage in his
+anatomical works he states the pleasure that he found in studying
+at last some human bones that had been deposited in a marshy place
+by a river which had overflowed its banks. We seem, then, to have a
+singular contradiction between these two facts, as we know on the one
+hand that the Greek artists have shown in their works a most rigorous
+anatomical exactitude, whilst on the other hand neither they nor their
+contemporary physicians and surgeons had made a study of the anatomy of
+man by the practice of dissection.
+
+But this contradiction disappears altogether when we examine the
+conditions which permitted those artists to have constantly before
+their eyes the nude human body, living and in motion, and so set them
+to work to analyse the forms, and thus to acquire, by the observation
+of the mechanism of active muscular changes, a knowledge almost as
+precise as that which is now obtained by the accurate study of anatomy
+and physiology. It is sufficient, in fact, to recall to mind the
+extreme care the ancients gave to the development of strength, and of
+physical beauty, by gymnastic exercises. In Homer we see the heroes
+exercising themselves in racing, in quoit-throwing, and in wrestling;
+later we come to the exercise of the athletes who trained themselves to
+carry off the palm in the Olympic games; and it is evident, in spite
+of the ideas that we hold now respecting wrestlers and acrobats, that
+the profession of an athlete was considered a glorious one, as being
+one which not only produced a condition of physical beauty and high
+character, but constituted in itself a true nobility. Thus the life
+of the gymnast came to exercise a decisive influence on Greek art.
+The prize of the conqueror in the Olympic games was a palm, a crown
+of leaves, an artistic vase; but the chief glory of all was that the
+statue of the victor was sculptured by the most celebrated artist of
+the time. Thus Phidias produced the handsome form of Pantarces, and
+these athletic statues form almost the only archives of the Olympiads,
+upon which Emeric David was able to reconstruct his Greek Chronology.
+From these works, which became ideals of strength and beauty, the
+artist had long been able to study his model, which he saw naked
+every day, not only before his exercises, whilst rubbing himself over
+with oil, but during the race, or the leaping match, which showed the
+muscles of the inferior extremities, or during the throwing of the
+quoit, which made the contractions of the muscular masses of the arm
+and the shoulder prominent; and during the wrestling matches, which
+from the infinite varieties of effort, successively brought all the
+muscular powers into play. Was it then surprising that the images
+of the gods, destitute of movement and of life, which had so long
+satisfied the religious sentiment of the people, were succeeded by
+artistic representations of man in action in statues such as could
+embody the idea of strength and beauty, studies of the living statues
+of the gymnasium? Further, we shall see the decline of art proceed side
+by side with the abandonment of the exercises of the gymnasium. Much
+later, in the Middle Ages, art awoke and embodied ideas in figures
+without strength and life indeed, but which nevertheless express in a
+marvellous manner the mysterious aspirations of the period; but these
+have not anything in common with the realistic representation of the
+human form, well developed and active, as seen in Greek art. At the
+time of the Renaissance, artists not having any longer a living source
+of study in athletic sports, recognised the necessity of seeking for
+more precise knowledge in the _anatomical_ study of the human
+body, in addition to the inspiration drawn from the study of the
+antique, and thus we see that the revival of the plastic arts occurred
+simultaneously with the introduction of the practice of dissection.
+This was not brought about without some difficulty.
+
+  [Illustration: FIG. 1.
+
+   Reproduction of a drawing of an anatomical study by Leonardo da
+   Vinci. (Choulant’s work, page 8.) This design represents the
+   minute dissection of the muscles of the lateral region of the
+   neck and trunk.]
+
+In the year 1230, Frederic II., Emperor of Germany, and King of the Two
+Sicilies, passed a law prohibiting the practice of medicine without
+the practitioners having first studied the anatomy of the human body.
+In spite of two papal excommunications hurled against the author of
+this edict, dissections were henceforth regularly pursued in Italy;
+and one century later--in the year 1316--Mondino di Luzzi was able to
+write the first treatise on human anatomy, containing descriptions
+made from studies of the dead body. This treatise was printed in 1478.
+Artists rivalled physicians in the ardour with which they pursued
+their anatomical studies; and it may be said that all the painters
+and sculptors in the fifteenth century gave most careful attention to
+dissection, or at least studied demonstrations made upon the dead body,
+for all have left, amongst their drawings, studies that leave no doubt
+on this head. Among the great masters it may be noted that Leonardo
+da Vinci (14521519) left thirteen portfolios of various drawings and
+studies, among which are numerous anatomical studies of remarkable
+fidelity. The greater number of these were taken from Milan by the
+French in 1796, and afterwards they were in part restored to Italy;
+some of them, however, went to enrich the British Museum in London,
+and were published by Chamberlain.[4] In Fig. 1 is reproduced one
+of these anatomical drawings. It shows with what care--perhaps with
+over-scrupulous care--the illustrious master endeavoured to separate
+by dissection the various fasciculi of pectoral muscle, deltoid, and
+sterno-cleido-mastoid. It may be noted also that in his _Treatise
+on Painting_, Leonardo da Vinci devotes numerous chapters to the
+description of the muscles of the body, the joints of the limbs and
+of the “cords and small tendons which meet together when the muscles
+contract to produce its action,” &c.; and finally, in this same
+_Treatise on Painting_, he makes allusion at different times to a
+_Treatise on Anatomy_, which he intended to publish, and for which he
+had gathered together numerous notes. These are fortunately preserved
+in the Royal Library at Windsor.
+
+Michael Angelo also (1475–1564) made at Florence many laborious studies
+of dissection, and left among his drawings beautiful illustrations
+of anatomy, of which several have been published in Choulant’s work,
+and by Seroux d’Agincourt.[5] Finally, we have numerous drawings by
+Raphael himself, as proof of his anatomical researches, among which we
+ought to mention, as particularly remarkable, a study of the skeleton
+intended to give him the exact indication of the direction of the limbs
+and the position of the joints for a figure of the swooning Virgin
+in his painting of the Entombment (Choulant, p. 15). We cannot end
+this short enumeration without quoting further the names of Titian
+and Andreas Vesalius, in order to show into what intimate relations
+artists and anatomists were brought by their common studies. Titian,
+in fact, is considered the real author of the admirable figures which
+illustrate the work--“De Humani Corporis Fabrica”--of the immortal
+anatomist, Andreas Vesalius, justly styled the restorer of anatomy. It
+is necessary, however, to add that though some of the drawings are by
+Titian, the greater number were executed by his pupil, Jan van Calcker,
+as is pointed out in the preface to the edition of the work published
+at Basle in 1543.
+
+The renaissance of the plastic arts and that of anatomy were therefore
+simultaneous, and closely bound up one with the other; ever since
+that time it has been generally recognised that it is necessary to
+get by anatomical study that knowledge of form which the Greeks
+found themselves able to embody in consequence of the opportunities
+they had of studying the human figure in the incessant exercises of
+the gymnasium. Again, in 1648, when Louis XIV. founded at Paris the
+_Académie de Peinture et de Sculpture_, which later on took the title
+of the _École des Beaux-Arts_, two sections of study were instituted
+side by side with the studios properly so called, for imparting to the
+pupils instruction considered as fundamental, and indispensable to the
+practice of art. These were the sections of perspective and anatomy.
+
+It is not our place to plead, otherwise than by the preceding
+historical considerations, the cause of anatomy in its relation to
+painting and sculpture; but we ought at least to examine what method
+is likely to prove the most useful for its study. If each anatomical
+detail does not correspond to an artistic need we are liable in
+following any treatise written with other than an artistic aim to be
+entangled in superfluous names and useless descriptions; while at the
+same time we might neglect details which are to the artist of great
+importance, although considered of secondary value by authors who have
+written especially for students in medicine.
+
+We ought, then, to ask ourselves, in the first place, what are the
+ideas that the artist should seek for in his study of anatomy? To this
+question all will reply that the ideas of proportion, of form, of
+attitudes and movements are those in which anatomy is relied upon to
+furnish precise rules; and as the expression of the emotions, either in
+painting or sculpture, cannot be reproduced except by various changes
+in the general attitude of the body, and in the special mechanism of
+the physiognomy moved by the muscles, we must conclude that our study
+should deal not only with proportions, form, attitudes and movements,
+but also with the expression of the emotions and passions. This, then,
+is the object to be attained. Suppose we try to accomplish it by
+examining in a first series of studies all that belongs to proportions;
+afterwards, in a second series, all that has relation to form; in a
+third, attitudes, &c. Such an order of proceeding, logical though
+it be, will have the disadvantage of causing numerous repetitions,
+and the more serious inconvenience of artificially separating parts
+which in the structure of the body are intimately connected. Thus,
+form is determined sometimes by osseous prominences, sometimes by
+the soft parts, which may be muscular or tendinous. Attitudes are
+determined by the muscles; but these are subject to laws which result
+from the position and action of the joints; so with movements in the
+expression of which it is necessary to consider, at the same time, what
+the conformation of the osseous levers (the direction of the bones
+and their articulation) allows, as well as that which the muscles
+accomplish, also the direction of the muscles and the differences of
+shape produced by their swelling and tension in action, as well as
+when the antagonistic muscles are relaxed. Proportions themselves
+cannot be defined without an exact knowledge of the skeleton, for it
+is the bones alone which furnish us with the landmarks from which to
+take measurements. A knowledge of the bones and of their articular
+mechanism is indispensable to us, that we may guard ourselves against
+being deceived in certain apparent changes of length in the limbs when
+certain movements take place.
+
+We see, then, that all the ideas previously enumerated as to
+proportion, form, attitude, movement, depend on the study of the
+skeleton and muscles. It will thus be easiest and most advantageous
+to proceed in the following manner:--We will first of all study the
+skeleton, which will teach us the direction of the axis of each part
+of the limbs, the relative lengths and proportions of these portions,
+and the osseous parts which remain uncovered by the muscles, and show
+beneath the skin the shape and the mechanism of the articulations in
+their relation to movements and attitudes. We shall then study the
+muscles, and endeavour to know their shapes, at the same time that,
+we complete the knowledge we shall have acquired of attitudes and
+movements. In the third place, we will attempt the analysis of the
+expression of the passions and emotions; and the study of the muscles
+of the face, of which the mechanism in the movements of the physiognomy
+is so special that it would be inconvenient to attempt to treat it with
+that of the muscles of the trunk and limbs.
+
+
+
+
+                             =First Part.=
+
+               THE SKELETON, ARTICULATIONS, PROPORTIONS.
+
+
+
+
+                             CHAPTER III.
+
+           OSTEOLOGY AND ARTHROLOGY IN GENERAL--NOMENCLATURE
+                          --VERTEBRAL COLUMN.
+
+   _Osteology_ and _Arthrology_.--Anatomical nomenclature:
+   median line; lateral parts; the meaning of terms.--Of the
+   bones in general: long bones (shafts and extremities);
+   flat bones (surfaces, borders); short bones.--Prominences
+   (processes, spines); cavities and depressions of bone
+   (fossæ, grooves).--Bone and cartilage.--The axial skeleton:
+   the vertebral column.--The vertebræ (bodies, transverse
+   processes, spinous processes, &c.).--Cervical, Dorsal, Lumbar
+   vertebræ.--Articulations of the vertebræ.--Movements of the
+   spine.--Movements of the head (atlas and axis).--The curves of
+   the vertebral column.--Relation of the vertebral column to the
+   surface.--Proportions of the parts of the spine.
+
+
+It is not necessary to emphasise further the importance of a study
+of the skeleton. By its means we obtain a knowledge of form and
+proportions; by a study of the several articulations we become
+acquainted with the complex mechanism by which the whole is knit
+together, and by which the movements of the various parts of the body
+occur. Further, the relations of the skeleton to the surface forms
+of different parts of the body are of fundamental importance. The
+science of _Osteology_ is the study of bones (ὀστέον, bone; λόγος,
+description); _Arthrology_ is the study of joints (ἅρθρον, a joint):
+_Myology_ is the study of muscles (μυς; λογος). The bones are the
+levers of movement: the articulations represent the fixed points or
+fulcra of these levers; while the powers which produce motion are
+represented by the muscles.
+
+  [Illustration: FIG. 2.
+
+  FRONT VIEW OF THE SKELETON.]
+
+  [Illustration: FIG. 3.
+
+  SIDE VIEW OF THE SKELETON.]
+
+Before describing in detail the different parts of the skeleton, it
+is necessary to consider the method of nomenclature, so that by the
+employment of proper terms the subsequent descriptions may be more
+intelligible.
+
+NOMENCLATURE.--In the description of the bones, as of other organs, we
+have to consider the relation of the portion under consideration to
+the rest of the body. The figure is always regarded as occupying the
+erect position, with the face, the palms of the hands, and the toes
+directed forward. Thus each bone, as well as the other organs or parts,
+will be found under one or other of two different conditions: either
+it is _median_ in position, and a vertical plane passing through the
+longitudinal axis of the body divides it into two similar segments;
+or else it is _lateral_ in position, and situated outside this median
+plane. As a type of the first class, we will take the _sternum_, or
+breast-bone (see Fig. 11, p. 42). This is a central single bone;
+it has no fellow, and is composed of two symmetrical portions, one
+part on the right and one part on the left. As a type of the second
+class, we will take the _humerus_ (Fig. 18, p. 60), which is a bone
+situated at the side and one of a pair, inasmuch as there are two,
+one on the right and one on the left of the median plane. From these
+two examples it is easy to understand that for the description of
+each _single and symmetrical_ bone it will be necessary to speak of
+anterior parts or surfaces directed towards the front of the body, of
+posterior parts (directed backwards), of lateral portions (right and
+left), and finally, of parts superior and inferior, looking upwards
+and downwards (in the case of the sternum a _superior_ and _inferior
+extremity_): on the other hand, in the description of a paired and
+_non-symmetrical_ bone, we shall also have to speak as heretofore of
+parts superior and inferior, anterior and posterior; but instead of two
+similar symmetrical portions, one on each side of an imaginary line, it
+has two dissimilar halves, of which the one looking towards the median
+plane--towards the axis of the body--is called the _internal_ part,
+and the other, looking to the outer side (as away from the axis), is
+called the _external_ part. It is necessary, for brevity and accuracy,
+to clearly comprehend the meaning of these terms in descriptive anatomy
+(anterior and posterior, internal and external, superior and inferior)
+which serve to show the relation of the parts to the skeleton as a
+whole.
+
+After this first division of bones into single and median, and into
+double and lateral, if we glance at the skeleton (Figs. 2, 3), it seems
+at first sight that the various bones present an infinite variety of
+shape, and defy classification or nomenclature; careful attention,
+however, will show us that they may be all included in one of the
+following three classes--viz., long bones, flat or broad bones, and
+short bones.
+
+  [Illustration: FIG. 4.
+
+   THE COMPLETE SKELETON (in the attitude of “The Fighting
+   Gladiator” of Agasias).]
+
+The long bones, which usually act as the axes of the limbs (_e.g._,
+the _humerus_, _femur_, _tibia_, &c.), are composed of a central
+portion, cylindrical or prismatic in shape, called the _body_, _shaft_,
+or _diaphysis_ (διαφύω, to be between), and of two extremities or
+_epiphyses_ (ἐπιφύω, to be at the end), usually marked by protuberances
+and articular surfaces. The flat bones (_e.g._, the _shoulder-blade_
+and the _hip bone_) are formed of osseous plates, on which are various
+_surfaces_, _borders_, and _angles_. Finally, the small bones, which
+are found in the vertebral column and in the extremities of the limbs,
+the hand and foot (_carpus_ and _tarsus_), present a diversity of form
+in which cylindrical, cubical, and wedge-like shapes can be made out.
+
+Whether the bone be long, flat, or short, it presents prominences and
+depressions. The projecting portions of bone are called by various
+names--_tuberosities_, _protuberances_, _processes_, _apophyses_,
+_crests_, _spines_, _tubercles_. To some of these names is added an
+adjective, which shows, more or less exactly, the form of the process
+or projection. Thus we speak of a _spinous process_, _mastoid process_
+(μαστὸς, a nipple; εἶδος, form), _styloid process_, &c. The depressions
+upon the bones are called by various names--_fossa_, _groove_,
+_foramen_, _sinus_, _canal_, _notch_, _cavity_, &c. To these also
+are added names which indicate their shape, as the _digital fossa_,
+from its resemblance to the imprint of a finger; the _glenoid cavity_
+(γλήνη, cavity), the _cotyloid cavity_ (χοτύλη, a basin); but more
+frequently still, the added adjective bears allusion to a connection of
+the cavity with certain organs, as the _bicipital groove_, that which
+contains the tendon of the biceps, or the _canine fossa_, in relation
+to the root of the canine tooth.
+
+_Structure of Bone._--Bone is characterised by its density, toughness
+and elasticity. If a long bone, such as the femur, is sawn in two
+lengthwise, its extremities are found to be composed of a delicate
+network of _cancellous_, or spongy bone, in the interstices of which
+marrow and blood are contained during life; the shaft of the bone
+is composed, for the most part, of a cylindrical tube of dense,
+ivory-like compact bone, which encloses the hollow medullary canal of
+the bone, also filled with marrow during life. The dense bone of the
+shaft is continuous with a thin sheet of hard bone, which covers over
+the spongy bone of the extremities.
+
+In the case of the flat and short bones, the structure is like that of
+the extremities of the long bones. The mass of the bone is composed of
+cancellous tissue, with a surrounding thinner envelope of compact bone.
+
+If a bone is burnt, it loses one-third in weight, becomes brittle,
+and loses its organic constituents, retaining its inorganic
+materials--chiefly calcium phosphate and calcium carbonate. If it
+is subjected to prolonged soaking in an acid such as hydrochloric
+acid, its inorganic salts are removed, it becomes soft and pliable,
+it loses two-thirds of its weight and retains only its organic
+materials--connective tissues. These in boiling produce glue.
+
+In certain situations bone is found in conjunction with a substance
+which differs from it in its elasticity, its want of rigidity (it is
+soft enough to be divided by the scalpel), and in its translucent
+colour. This substance is known by the name of cartilage. Thus the
+curved bones termed ribs are prolonged at their anterior extremities by
+a portion called the _costal cartilage_, which presents the same form
+as the ribs properly so called. The bones forming the freely movable
+joints (like the shoulder, hip and knee joints) are capped by thin
+layers of hyaline _articular cartilage_, which forms a pliant elastic
+cushion in relation to the articulation.
+
+Most of the bones, at the commencement of their formation, are
+constructed solely of cartilage, which is gradually transformed into
+bone as the animal grows by the deposition in it of lime salts; and
+this transformation of primitive cartilage into bone may be more or
+less complete according to the species or age of the animal. With
+advancing age the bones tend to become more and more calcified. Thus
+we find that in the skeletons of old people the costal and other
+cartilages may be more or less ossified.
+
+_The Subdivisions of the Skeleton._--The human skeleton is
+characterised by peculiarities due to the assumption of the erect
+position, the high development of the brain, and the possession of
+extraordinary manual dexterity. All these factors leave their impress
+on the bones of the skeleton, as may be seen by comparing the human
+skeleton with that of such a quadruped as the dog.
+
+The skeleton is subdivided into _axial_ and _appendicular_ parts. The
+axial skeleton includes the vertebral column, ribs and sternum, and the
+bones of the cranium and face. The _appendicular_ skeleton comprises
+the bones of the limbs. In the following pages, for convenience of
+description, an account will be given of the vertebral column, sternum,
+and ribs first; of the limbs second; reserving to the last the account
+of the skeleton of the cranium and face.
+
+_The Vertebral Column._--The vertebral column (Figs. 5, 8) is composed
+of a number of bones named _vertebræ_, superimposed on one another, and
+partially separated from one another by a series of _intervertebral
+discs_. The column is subdivided into groups of vertebræ, by reason of
+its connections with other parts of the axial skeleton, or with the
+skeleton of the limbs.
+
+  [Illustration: FIG. 5.
+
+   THE VERTEBRAL COLUMN (antero-lateral aspect).--1, the first
+   cervical vertebra (atlas);--9, 9, its occipital articulating
+   surfaces;--2, the second cervical vertebra, or axis;--13, its
+   body;--4, seventh cervical;--5, 5, transverse processes of the
+   ten first thoracic vertebræ;--8, 8, transverse processes of the
+   lumbar vertebræ;--10, 11, 12, articular processes;--19, 19,
+   bodies of the lumbar vertebræ;--20, the sacrum;--21, the coccyx.]
+
+The _head_ is poised on the upper end of the column, and causes the
+peculiarities, to be described later, in the first two vertebræ
+(_atlas_ and _axis_). The attachment of the ribs to the sides of
+the vertebral column causes the separation of three regions: (1)
+_cervical_, belonging to the neck, and comprising seven vertebræ;
+(2) _thoracic_ (or dorsal), belonging to the _thorax_, or chest, and
+comprising twelve vertebræ; and (3) _lumbar_, belonging to the loin,
+and comprising five vertebræ. The attachment of the hip bones to the
+sides of the succeeding vertebræ leads to the fusion of the next five
+vertebræ together, under the name of the _os sacrum_, which will be
+described along with the _hip bone_ and _pelvis_. Finally, below the
+sacrum are four small, rudimentary vertebræ, known as the _coccyx_,
+forming the attenuated remains of a caudal appendage.
+
+There are thus, altogether, normally thirty-three vertebræ: seven
+cervical, twelve thoracic, five lumbar (constituting together
+twenty-four movable vertebræ); five sacral, and four coccygeal vertebræ
+(constituting nine fixed vertebræ, which help to form the pelvic basin).
+
+  [Illustration: FIG. 6.
+
+   OUTLINE OF A VERTEBRA (upper surface).--_0_, vertebral
+   foramen;--1, spinous process;--2, body of vertebra;--3, 3,
+   transverse process with articulating facets (4, 4) for the
+   tuberosity of the rib (see p. 30);--5, 5, superior articular
+   processes;--6, 6, the parts which connect the body with the base
+   of the transverse and articular processes;--7, 7, vertebral
+   laminæ.]
+
+The vertebral column is intended not only to form an axis for the
+rest of the skeleton, but also to serve as an attachment, direct or
+indirect, for all the other bony structures; it also forms a bony
+canal, within which the spinal marrow is contained. It is for this
+reason that each of the pieces which compose it, called a vertebra,
+is a sort of bony ring (Fig. 6). The anterior portion of the ring is
+very thick, representing the segment of a cylinder, and is called the
+body of the vertebra (2, Fig. 6); and the vertebral column, considered
+as the median column of support, is essentially constituted by the
+superposition of these vertebral bodies upon one another, separated
+by the intervertebral discs. Behind each vertebral body is an arch,
+the _neural arch_, which encloses the neural ring. The spinal or
+_neural canal_ is formed by the combination and connection together of
+the neural rings. Each neural arch is comparatively slender, but it
+gives origin to certain projections or processes, three in number,
+on each side, of which one directed transversely outwards is called
+the _transverse process_ (3, Fig. 6). In the thoracic region these
+give partial attachment to the ribs. The other two--directed more or
+less vertically, one above, the other below--are called the _articular
+processes_, superior and inferior. These serve for uniting together the
+arches of adjoining vertebræ (5, 5, Fig. 6). Finally, the posterior
+portion of the neural arch is prolonged backwards as a protuberance,
+more or less pointed, called the _spinous process_ (1, Fig. 6).
+
+Such are the most important parts which we find in each vertebra, but
+they present particular characters according to the region to which
+each vertebra belongs. The description of the sacrum and the coccyx,
+which are formed of vertebræ welded together, and articulating with the
+hip bones, will be given with that of the pelvis.
+
+The more important features of the movable vertebræ which contribute
+to give to the whole column its general form are: (1) the size,
+particularly of the bodies, of the vertebræ; and (2) the characters of
+the transverse processes. The bodies of the vertebræ are smallest in
+the upper thoracic region, and increase in size upwards and downwards
+from the fourth thoracic vertebra. The bodies are largest and most
+prominent in the loin; in the neck the vertebræ are broad in the
+transverse diameter, but their antero-posterior diameters are less.
+The vertebral column is weakest in the upper thoracic and upper lumbar
+regions, and most mobile in the neck and thorax. Rotary power in the
+loin is practically prevented by the shape of the lumbar articular
+processes, which interlock the vertebral arches in this region.
+
+  [Illustration: FIG. 7.
+
+   THE MOVABLE VERTEBRÆ.--A, atlas (upper surface); B C, axis; D E,
+   cervical vertebra; F G, thoracic vertebra; H I, lumbar vertebra.]
+
+The _spinous processes_ of the vertebræ, which project more or less
+obviously in the middle line beneath the skin in different regions, in
+the cervical region are short and bifid; in the thoracic region they
+are long, sloped downwards, and “bayonet-shaped”; in the lumbar region
+they are directed straight backwards, and are “hatchet-shaped.”
+
+Besides these general characters in each region there are certain
+vertebræ which demand special mention owing to the peculiarities of
+their shape. These are the first two and the last cervical.
+
+The _first cervical_ vertebra (Fig. 7, A), called the _Atlas_, because
+as directly supporting the head, it has been compared to the giant
+Atlas, supposed by the ancients to support the heavens, is a bony ring
+with only transverse processes, and on the upper and lower aspects of
+its lateral portion, two pairs of articular surfaces; the superior
+articular surfaces are hollow oval surfaces which articulate with the
+convex condyles of the occipital bone; and by the _occipito-atlantoid_
+joints provide for flexion and extension of the head on the spinal
+column. The inferior articular surfaces are flat and directed downwards
+to articulate with the axis and form the _atlanto-axial_ joint, which
+is responsible for the movement from side to side of the head upon the
+trunk. The _axis_, or second vertebra (Fig. 7, B C), is so called from
+the presence on the upper surface of its body of a tooth-like process,
+the odontoid process (ὀδοὺς, tooth; ἔιδος, form), which projects
+upwards in an osseofibrous ring formed by a transverse ligament in
+the anterior part of the ring of the atlas. Ligaments extend from this
+process to the occipital bone, and it forms a pivot round which the
+head _and_ the atlas move in the lateral movements of the head upon the
+spinal column.
+
+In nodding the head the movement occurs primarily at the
+occipito-atlantoid joint; in shaking the head, the chief movement
+is between the atlas and axis. These functions, of no moment in the
+production of surface forms, are of too great an importance in respect
+of the articulations of the head and trunk to be omitted here.
+
+  [Illustration: FIG. 8.
+
+   VERTEBRAL COLUMN (lateral view).--1 to 7, bodies of cervical
+   vertebræ;--8 to 19, bodies of thoracic vertebræ;--20 to 24,
+   bodies of lumbar vertebræ;--A, A, spinous processes;--B, B,
+   articular surfaces of transverse processes for the tuberosities
+   of the ribs;--C, auricular surface of sacrum.]
+
+The _seventh_ cervical vertebra, or _vertebra prominens_, is so
+called because of the extraordinary length of its spinous process,
+which, except in very stout people, forms a projection easily visible
+beneath the skin; and this projection is also more conspicuous as
+it corresponds to that part of the neck where the trapezius muscle,
+represented only by a fibrous layer--not fleshy--forms a flat surface
+at the back of the neck. In the centre of this surface the projection
+of the seventh cervical spine appears on the level of a transverse line
+passing through the superior border of the shoulder (see Fig. 3). It
+may be observed that when the model bends the head forward the spinous
+process of the seventh cervical becomes very prominent. It should
+also be noted that in the majority of cases the spinous processes of
+the _sixth cervical_ and _first thoracic_ vertebræ also give rise to
+superficial projections above and below that produced by the _vertebra
+prominens_.
+
+We have been disconnecting the vertebræ in order to account for
+the construction of the vertebral column; we must next see how the
+different vertebræ are placed one upon the other--how they articulate
+in such a manner as to form a column, not rigid, but elastic and
+curved. The vertebræ are placed one on each other so that the inferior
+articular processes of one fit exactly on to the superior articular
+processes of the next beneath, and thus throughout the series we see
+(Fig. 8) that the bodies of the vertebræ are not in contact one with
+the other, the space which separates them being filled in the living
+subject by elastic fibrous discs. These _intervertebral discs_ are
+very thick in the lumbar region, and become thinner in proportion as we
+ascend to the superior dorsal and cervical regions. They are thicker
+in the cervical and lumbar regions than in the thorax; and taken
+together they form one-seventh of the length of the spinal column.
+Being compressible and elastic, these fibrous discs give to the column,
+formed by the placing one on another of the bodies of the vertebræ, a
+certain degree of flexibility, whereas a column formed of bone alone
+would have been quite rigid.
+
+In addition to the intervertebral discs, a series of ligaments which
+join together the posterior portions of the neural arches (_laminæ_)
+is of great importance. Composed of yellow elastic tissue to a large
+extent, they are known as the _ligamenta subflava_. They consist of two
+short bands placed on each side of the root of the spinous process,
+uniting the inferior border of the lamina of one vertebra with the
+superior border of the lamina situated next below it.
+
+The _yellow_ or _elastic_ tissue which composes these ligaments is
+similar to a piece of india-rubber; it is elastic--that is to say, it
+is able to stretch, and to return again by its own reaction to its
+original size when the cause which extended it has ceased to act: so
+that each movement of flexion of the column in front results in moving
+the vertebræ on one another, at the same time stretching these elastic
+ligaments. When the anterior muscles of the trunk which accomplish
+this flexion cease to contract, it is not necessary, in order to
+straighten the column, that the posterior muscles of the back should
+come into play; the elasticity of the ligamenta subflava suffices for
+this, as they return to their original dimensions and draw together the
+vertebral laminæ. We may say, then, that there is at the posterior
+portion of the column within each vertebra a pair of small springs
+which keeps the column erect, so that the erect attitude of the trunk
+is maintained simply by the presence of the elastic ligaments; although
+more is required when a man supports upon his back any extra weight or
+burden.
+
+_The Ligamentum Nuchæ_ (paxwax) is a large and powerful ligament
+composed of yellow elastic tissue. It is highly developed in
+quadrupeds, and is attached between the spinous processes of the
+cervical vertebræ and the occipital crest, a vertical ridge on the back
+of the skull. In man it is a rudimentary structure (as the head is
+poised on top of the vertebral column) and forms a membranous partition
+separating and giving partial attachment to the muscles of either side
+at the back of the neck.
+
+_Curves of the Vertebral Column._--The vertebral column is subject
+to a slight lateral curvature, generally towards the right side. Its
+chief curves, however, are antero-posterior, and are four in number
+(Fig. 8): two, the thoracic and sacral curves, concave forwards, are
+primitive embryonic curves; two, cervical and lumbar, convex forwards,
+are secondary in their origin. The convexity forwards of the cervical
+region is to be connected with the raising upwards of the head on the
+trunk; the convex lumbar curve is due to the straightening of the lower
+limb, which in the course of development is brought into line with the
+vertebral axis.
+
+These curves (except the pelvic or sacral curve) are to be associated
+with a difference in the thickness in front and behind of the vertebral
+bodies, and of the intervertebral discs in the different regions of
+the spine.
+
+In most animals the vertebral column has but two curves, one the
+cervical curve, which is convex inferiorly, the other the dorso-lumbar,
+which is concave inferiorly.
+
+We have now to examine the influence that the vertebral column has in
+moulding the external form of the body, and to see if the length of the
+column can be made use of for a system of proportion.
+
+It is evident, in the first place, that the posterior portions of
+the vertebræ only can affect the outline of the body, the anterior
+portions, the bodies of the vertebræ, being deeply hidden in the cavity
+of the thorax and abdomen. Therefore, in the skeleton the posterior
+surface of the vertebral column (Fig. 9) presents itself under the
+aspect of a median crest, formed by a series of spinous processes, the
+_spinal crest_, on each side of which is a groove bounded laterally
+by the series of transverse processes (the _vertebral furrow_). In
+the living subject these grooves are filled up by powerful and thick
+muscles, which project in such a manner that in the erect position
+the back presents a furrow in the median line bounded on each side by
+these muscles, at the bottom of which furrow the bony structure of the
+vertebral column is shown only by a series of projections placed one
+beneath the other, like the beads of a necklace, each one being formed
+by the summit or free extremity of a spinous process. These projections
+are well seen in the thoracic region, in which the curvature of the
+column is convex backwards, and they show themselves still more
+clearly when the subject bends forward, and thereby increases this
+curvature. They are not visible in the cervical region, where the
+ligamentum nuchæ projects to the surface, and a bed of powerful muscles
+covers them; but we have seen that the seventh cervical, or _vertebra
+prominens_--along with the sixth also in many cases--is remarkable for
+the projection which its spinous process makes. Finally, in the lumbar
+region these projections are but little marked, the spinous processes
+here being short and terminated not by points, but by straight borders
+(Fig. 8).
+
+  [Illustration: FIG. 9.
+
+   VERTEBRAL COLUMN (posterior view).--1, 1, cervical transverse
+   processes;--2, 2, thoracic transverse processes;--3, 3, lumbar
+   transverse processes;--7, 8, 9, 10, spinous processes;--11, 11,
+   articular surfaces for occipital bone of skull;--12, odontoid
+   process of the axis;--13, 14, sacrum and coccyx.]
+
+The measurements of the vertebral column are useful, on the one hand,
+as absolute measurements of length and height, and, on the other hand,
+in giving the ratio of its length to the stature of the subject.
+The height of the vertebral column in the average adult man is from
+twenty-three to twenty-four inches, being five for the cervical region,
+eleven for the thoracic, and seven inches for the lumbar region. But as
+the length of the vertebral column does not serve as a common measure
+for the total height of the body or for its different parts, it cannot
+be used as the basis of a system of proportion. A German zoologist,
+Carus, has advanced the idea that the length of the column forms one
+third of the height; but this proposition is not exact. On the other
+hand, it is not easy to measure the column from the atlas as far as the
+last lumbar vertebra, without taking account of the sacrum and coccyx.
+It will be more frequently found that the length of the trunk, from the
+superior limit of the thorax to the inferior limit of the pelvis, gives
+a measurement more easy to take, and more useful for comparing the
+general proportions of the body.
+
+  [Illustration: FIG. 10.
+
+  OUTLINE OF THE BACK AND SHOULDERS.]
+
+It is enough to say here that the proportion of the vertebral column
+to the height varies according to age and sex, and according as the
+stature of the individual is very great or very little; the vertebral
+column is, in fact, in comparison with the height, longer in the infant
+and in the female than in the adult male; it is also much longer in
+proportion to the height in subjects of short stature than in tall
+people. The cause of difference of stature between men and women,
+infants and adults, long people and short, is principally due to the
+length of the lower extremities--a question which will be dealt with in
+a subsequent chapter.
+
+
+
+
+                              CHAPTER IV.
+
+                              THE THORAX.
+
+   The Sternum: its three portions--manubrium, gladiolus,
+   xiphoid appendage; position and direction of the sternum; its
+   dimensions, absolute and relative.--The ribs; the true ribs,
+   the false and floating ribs; the obliquity and curvature of the
+   ribs.--Of the thorax in general; its posterior aspect, anterior
+   aspect, and base.
+
+
+We have already seen that that portion of the vertebral column which
+is formed by the seven cervical vertebræ is free, and forms of itself
+the bony structure of the _neck_. It is the same in the lumbar region,
+where the five vertebræ alone form the bony structure of the abdomen.
+The twelve thoracic vertebræ, however, corresponding to the upper
+two-thirds of the trunk, are in connection with the ribs and sternum,
+and constitute with these bones the osseous frame-work of the _thorax_.
+
+THE STERNUM.--In the front part of the thorax is the sternum, a bone
+in the middle line, single and symmetrical (Fig. 11). This bone is, in
+quadrupeds, formed of a considerable number of separate bones jointed
+together in a linear series. In the human subject it consists of three
+separate parts, one superior, one in the middle, and one inferior,
+known respectively as the pre-sternum, meso-sternum, and meta-sternum.
+The whole bone has been compared in shape to a short Roman sword, of
+which the pre-sternum represents the handle, or _manubrium_; the
+meso-sternum, the longest piece, is the body, or _gladiolus_; and
+the meta-sternum, the pointed extremity of the sword, and usually
+tipped with cartilage, is the _ensiform_ or _xiphoid_ cartilage. Thus
+constituted, the sternum presents for our consideration an anterior
+surface, a posterior surface, two lateral borders, an upper and a lower
+extremity.
+
+  [Illustration: FIG. 11.
+
+   THORAX (anterior view).--1, pre-sternum, or manubrium of
+   sternum;--2, meso-sternum, or body;--3, meta-sternum, or xiphoid
+   appendage;--4, body of first thoracic vertebra;--5, twelfth
+   thoracic vertebra;--6 and 7, first and second ribs;--8, 8, the
+   true or sternal ribs;--9, 10, the floating ribs;--11, costal
+   cartilages.]
+
+The anterior surface is smooth, but the union of the manubrium with the
+body of the sternum is marked by a prominent transverse ridge (sternal
+angle), due to the difference in direction of the two pieces at their
+junction. This projecting angle is very remarkable in some subjects,
+and gives a clearly marked convex shape to the superior portion of the
+anterior surface of the thorax. The posterior surface of the bone,
+which it is not necessary for artists to study, is generally flat, and
+presents a returning angle corresponding to the projecting angle of the
+anterior surface.
+
+The superior extremity of the sternum, forming the broader portion of
+the bone, is marked by three notches, or depressions: two lateral,
+one on each side, articulating with the inner end of the clavicle,
+and one in the middle called the suprasternal, or episternal, notch.
+This notch, which is easily discerned on the living model, forms the
+inferior border of the deep depression situated at the lower part of
+the front of the neck. Its depth is still further increased by the
+inner ends of the clavicles and by the sterno-cleido-mastoid muscles on
+either side.
+
+The inferior extremity of the sternum is formed by the meta-sternum, or
+xiphoid appendage, which remains very frequently in the cartilaginous
+state, in the form of a plate, thin and tapering. In shape and
+direction it is very variable, being sometimes pointed, rounded, or
+bifurcated. It may be situated in a plane corresponding to that of the
+body of the sternum, or it may be placed obliquely or project forwards
+or backwards. In a case where it projects in front it may cause a
+slight elevation of the skin of the region of the pit of the stomach,
+or epigastrium; but it is a detail of form so irregular that it is not
+worth reproducing, except in the representation of violent muscular
+exertion or extreme attenuation.
+
+The lateral borders of the sternum are not vertical, but concave. The
+sternum is narrowest at the manubrio-sternal junction, the manubrium
+increasing in size towards its upper end, and the gladiolus, or body
+of the bone, enlarging towards its inferior part. Each lateral border
+is marked by seven small notches, or depressions, for the reception of
+the anterior extremity of each of the cartilages of the first seven
+ribs. The highest of these depressions is situated on the border of
+the manubrium just below the clavicular articular surface; the second
+depression is situated opposite the manubrio-sternal junction, partly
+on the pre-sternum, partly on the meso-sternum; those following are
+situated on the edge of the body of the bone, or meso-sternum, and
+the spaces between the depressions become smaller as they approach
+its lower extremity, so that the last depressions for the sixth and
+seventh costal cartilages are almost fused into one. The seventh costal
+cartilage is usually attached opposite the sterno-xiphoid junction, and
+is thus connected with both meso-sternum and meta-sternum.
+
+It is necessary also to determine the exact position and direction
+of the sternum in relation to the other parts of the thorax, in the
+complete skeleton. The direction of the sternum is not vertical, but
+very oblique; it forms an angle of fifteen to twenty degrees, with a
+vertical line passing through the inferior extremity (Fig. 12), and
+an angle of severity to seventy-five degrees, with a horizontal line
+passing through the same extremity (Fig. 12). The manubrium is more
+oblique than the body of the sternum, and the body of the sternum than
+the xiphoid cartilage. Such is the direction of the sternum in the
+male; in the female it is less oblique, and approaches the vertical--a
+disposition which artists are prone to exaggerate by giving a more
+rounded form to the superior portion of the thorax in the female.
+
+  [Illustration: FIG. 12.
+
+  RELATIONS OF THE STERNUM TO THE VERTEBRAL COLUMN.]
+
+To compare the relations of the sternum with the rest of the thorax, it
+is necessary further to determine the level of the parts corresponding
+to the two extremities in relation to the vertebral column. The upper
+end of the sternum does not correspond to the first thoracic vertebra,
+but rather to the disc which separates the second and third, so that
+the horizontal plane passing through the superior extremity of the
+sternum strikes the second thoracic vertebra at its lower part (Fig.
+12). The horizontal plane passing through the lower end of the sternum
+strikes the tenth thoracic vertebra; so that, viewing the thorax in
+profile, the sternum is seen to project between the second and eleventh
+vertebræ. The exact level of the bone varies with the movements of the
+chest wall in respiration.
+
+The average length of the sternum in the adult man is eight inches.
+The pre-sternum, or manubrium, is usually about half as long as the
+meso-sternum, or body of the bone.
+
+The most important measurement, however, is the length of the sternum
+_without the xiphoid appendage_. A measurement equivalent to the length
+of the sternum is found in various parts of the skeleton, which for
+the most part are adjacent to the sternum, and the sternal length may
+be taken as a common measure for constructing a correctly proportioned
+torso.
+
+As a fact, this measure of the length of the manubrium and body of the
+sternum is equal to (1) the clavicle, to (2) the vertebral border of
+the shoulder-blade, and to (3) the distance which separates the two
+shoulder-blades in the figure when the arms are hanging by the side;
+further, the length of the sternum is equal to (4) the length of the
+hand without the third phalanx of the middle finger.
+
+THE RIBS.--The thoracic part of the vertebral column and the sternum
+being known, it is easy to understand the arrangement of the parts
+which complete the thorax. These parts are the ribs and costal
+cartilages, arranged somewhat like the hoops of a cask, proceeding from
+the vertebral column to the sides of the sternum; the ribs articulate
+posteriorly with the vertebral column, and are connected anteriorly to
+the sternum or to one another by the costal cartilages. The ribs are
+twelve in number on each side. They are known as first, second, and
+third ribs, etc., counting from above downwards; the first seven are
+the _true ribs_, or _sternal_ ribs, which have their costal cartilages
+directly joined to the sternum; the next three (eighth, ninth, and
+tenth) ribs are the _vertebro-costal_ ribs, as the costal cartilage of
+each articulates with the cartilage of the preceding rib; the last two,
+the eleventh and twelfth, are the _false_, _floating_ or _vertebral_
+ribs: they are remarkable for their shortness; they are provided at
+their extremities with only rudimentary cartilages, which are pointed,
+and project by free extremities among the muscles of the walls of the
+abdomen.
+
+In a general sense the ribs are long bones, presenting an external
+surface and an internal surface, a superior border and an inferior
+border. They are not horizontal, but oblique, from above downwards and
+from behind forwards: so that the anterior extremity of a rib is always
+placed on a lower level than its posterior extremity.
+
+A typical rib possesses three curves. It is bent from behind forwards
+in a downward direction; it is bent like the hoop of a cask in order
+to surround the thorax, and presents, therefore, a curve similar to
+that of a scroll, of which the convexity is turned outwards and the
+concavity inwards; and, again, it is twisted upon itself as if the
+anterior extremity had been forcibly carried inwards by a movement
+of rotation upon its own axis. This curvature of torsion makes the
+surface, which is really external in the central portion of the rib,
+become a superior surface in the anterior portion. In order to have a
+good idea of the torsion of the ribs it is necessary to take a single
+rib and place it on a horizontal surface, such as a table; it will be
+then seen that, instead of its being in contact through its entire
+extent with the flat surface, it touches it only at two points, as if
+it formed a half-hoop of a cask to which a slight spiral twist had been
+given.
+
+The ribs vary much in length, in order to correspond to the ovoid shape
+of the thorax; their length increases from the first to the eighth,
+which is the longest, and corresponds to the largest part of the
+thorax; and it gradually diminishes from the eighth to the twelfth.
+
+A typical rib (Fig. 13) consists of the following portions, an
+indication of which is useful for the study of the shape of the thorax.
+The posterior extremity is slightly raised, and constitutes the head
+of the rib. It is shaped like a wedge, and articulates with the bodies
+of two vertebræ as a rule, and it is received, precisely like a wedge,
+into the space which separates the bodies of these vertebræ; so that
+it is in contact by the summit of the wedge with the intervertebral
+disc, and by the surfaces of the wedge with the vertebra which is
+situated above and that which is situated below the disc. Beyond the
+head, the rib presents a portion thin and compressed from before
+backwards, called the _neck_ of the rib, which is placed in front of
+the transverse process of the vertebra corresponding to it.
+
+At the external extremity of the neck is a slight enlargement called
+the _tubercle_, which corresponds to the level of the external
+extremity of the transverse process of the vertebra, and which
+articulates with the corresponding transverse process (Fig. 7, F G). By
+means of the connections of the head with the bodies of the vertebræ,
+and of the tubercle of the rib with the transverse process of the
+thoracic vertebra which corresponds to it, the posterior end of the rib
+moves on these joints as on a fulcrum, in the act of respiration; the
+chest cavity being enlarged by the uplifting of the shaft of the rib
+and by the eversion of the rib simultaneously.
+
+  [Illustration: FIG. 13.--A TYPICAL RIB.]
+
+Passing on from the tubercle, the _shaft_ of the rib is formed of a bar
+of bone, which at first is directed outwards and backwards (Fig. 13);
+then, after travelling some distance, it bends abruptly, so as to be
+directed forward, describing the characteristic curve of the rib. We
+give to this bend the name of the _angle_ of the rib. The series of the
+angles of the ribs shows, upon the posterior aspect of the thorax, a
+line plainly visible, curved, with its convexity outwards, and having
+its summit at the level of the eighth rib, which is the longest, and
+upon which a relatively greater distance separates the angle from the
+tubercle.
+
+  [Illustration: FIG. 14.
+
+   THORAX (posterior view).--1, 1, spinous processes of the
+   thoracic vertebræ;--2, 2, vertebral laminæ;--3, 3, series of
+   transverse processes;--4, 4, the parts of the ribs included
+   between the tuberosities and the angles of the ribs;--5, 5,
+   angles of the ribs, becoming more distant from the vertebral
+   column as the rib becomes more inferior.]
+
+Such are the characters of ribs in general. For the peculiar characters
+of the several ribs, after we have spoken of the last two ribs, it
+will suffice to note the shortness of the upper ribs, and principally
+of the first, which is flattened from above downward. In other words,
+it is curved along the borders, and not along the surfaces, and it
+does not present any twist. The last two ribs, besides being the
+shortest as a rule (excepting the first rib), are peculiar in their
+straightness and in the rudimentary nature of the angles; they further
+have no articulation with the transverse processes of the corresponding
+vertebræ.
+
+The _costal cartilages_ are attached to the extremities of the ribs
+in front: these cartilages, in proceeding to join the sternum, follow
+a course more or less oblique, so that the cartilage of the first rib
+is oblique from above downwards, and from without inwards; and those
+following present the same obliquity (Fig. 11), which becomes more
+accentuated in the cartilages lower down. The spaces which separate
+these cartilages are wide above, especially between the cartilages of
+the three first ribs, and become narrower towards the lower part of the
+chest.
+
+_The Thorax as a Whole._--The thorax, the constituent parts of which we
+have just examined, forms a kind of truncated cone, with its base below
+and its apex above; but, from an artist’s point of view as to form, it
+is not necessary to take this into account, as the shape of the summit
+of the thorax is completely changed by the addition of the osseous
+girdle constituted by the clavicle and shoulder-blade.
+
+We limit ourselves, then, to a rapid view of the posterior surface, the
+anterior surface, and the base of the thorax.
+
+The posterior surface (Fig. 14) presents upon the skeleton, in the
+median line, the series of spinous processes, and on each side, first a
+row of transverse processes and then the angles of the ribs. As already
+explained (p. 37), respecting these several details, the summits of the
+spinous processes, although just under the skin, are scarcely visible,
+especially in a very muscular subject.
+
+On the anterior surface of the thorax (Figs. 11, 15), in a muscular
+subject, the osseous details do not show on the external figure, with
+the exception of the _episternal_ or _suprasternal notch_ (p. 43), and
+the inner ends of the clavicles, which are more or less visible. The
+great pectoral muscles form on each side a large fleshy surface, and
+the median line of separation of these muscles is marked by a narrow
+depression corresponding to the central portion of the sternum, the
+only region where this bone becomes subcutaneous; but in less muscular
+subjects, in the aged and in thin children, all the details of the
+thoracic frame-work show beneath the skin, and clearly reveal the forms
+of the costal cartilages with their obliquities, the thin intervals
+of separation (_intercostal spaces_) becoming narrower as we get
+lower down. Moreover, especially in infants, the articulation of the
+cartilages with the sternum, and the articulation of the cartilages
+with the anterior extremities of the ribs, are shown by a double row
+of nodules, as the points of junction of the osseous and cartilaginous
+portions are slightly elevated. We find therefore a series of
+_chondro-sternal_ nodules (χόνδρος, cartilage) marking the borders
+of the sternum, and, on the outer side, a series of _chondro-costal_
+nodules, marking the line of junction of the ribs with the cartilages.
+This chondro-costal line descends obliquely from within outwards; so
+that, above, it is very near the sternum, owing to the shortness of
+the cartilage of the first rib, and, below, it is withdrawn from the
+sternum owing to the greater length of the cartilages of the ninth and
+tenth ribs.
+
+  [Illustration: FIG. 15.
+
+  FRONT VIEW OF THE CHEST AND ABDOMEN.]
+
+The _base_, or _inferior circumference_, of the thorax is continuous,
+without distinct limits upon the living subject, with the abdominal
+wall behind and laterally; but in front this circumference presents
+a depression in the form of an inverted =V=, with the mouth looking
+downwards (Fig. 11); this depression, limited on both sides by the
+cartilages of the lower six ribs, and corresponding at its apex to the
+junction of the body of the sternum with its costo-xiphoid appendage,
+shows in the living subject a depression of the same form, called the
+pit of the stomach, or _epigastrium_ (ἐπὶ, upon; γαστήρ, stomach). Upon
+the dead body, or upon a model in a state of repose, the outlines of
+the pit may be compared to a pointed arch; but when the model makes a
+violent effort, as in taking a deep inspiration, the elevation of the
+ribs spreads the cartilages of the false ribs from the median line,
+and the pointed arch in question shortens and tends to take a rounded
+form. On the other hand, in very muscular subjects, the great anterior
+muscles of the abdomen are sufficiently thick at their superior parts,
+where they cover the cartilages of the false ribs, to add their shape
+to that of the cartilages, and to give to the epigastric region a
+more rounded form. It is this form of a rounded arch that the Greek
+sculptors have adopted almost exclusively, and this choice we find
+justified to some extent in the fact that they had for their models
+very muscular athletes, whom they studied during the wrestling-matches
+of the gymnasium, when efforts which dilated the thorax most powerfully
+were to be observed.
+
+
+
+
+                              CHAPTER V.
+
+                             THE SHOULDER.
+
+   The bones of the shoulder.--The clavicle: its shaft and
+   extremities, sternal and acromial: its proportions.--The
+   shoulder-blade: its situation and relations.--The spine
+   of the scapula: acromion: coracoid process: glenoid
+   cavity.--Proportions of the scapula: the distance which
+   separates the right from the left scapula.--The upper portion
+   of the humerus: the anatomical neck, the surgical neck:
+   the articular head: the tuberosities.--The shoulder-joint:
+   its movements: the increase of mobility assured by the
+   acromio-clavicular and sterno-clavicular articulations the
+   to-and-fro motion of the scapula: the importance of this
+   mechanism with regard to external form.
+
+
+The shoulder is formed of three bones, of which one is situated in
+the front, the _collar-bone_, or _clavicle_; a second is behind, the
+_shoulder-blade_, or _scapula_; and a third is placed externally, the
+upper part of the _arm-bone_, or _humerus_.
+
+The _clavicle_ (_clavicula_, diminutive of _clavis_, a key) is a
+long bone, placed horizontally at the junction of neck and chest. It
+connects the breast-bone with the shoulder-blade; and the two clavicles
+are separated in the middle line by the upper end of the manubrium, or
+pre-sternum (episternal or suprasternal notch). Its form is that of
+an italic ∫--that is to say, it describes in a horizontal plane two
+curves, the internal portion being convex in front, and the outer part
+convex behind (Fig. 16). It consists of a shaft and two extremities:
+the _shaft_, flattened from above down, presents a smooth _superior
+surface_, which in the model shows very clearly beneath the skin, and a
+rough _inferior surface_ for the attachment of a muscle (subclavius),
+and for the attachment of ligaments connecting it with the first rib
+internally, and with the coracoid process of the scapula externally
+(see below); it possesses a _posterior_ and an _anterior border_, thick
+and curved: an _internal, sternal extremity_, thick and triangular,
+which articulates with the corresponding lateral facet on the manubrium
+of the sternum: and an _outer, acromial extremity_, flattened and
+presenting an oval articular surface for articulation with the acromion
+process of the scapula. The clavicle thus serves to connect the scapula
+to the trunk, and by the articulations of its two extremities it
+increases, as we shall see, the mobility of the shoulder-joint. We find
+that the clavicle, which is almost horizontal when the arms are hanging
+in an attitude of repose beside the trunk, becomes oblique in direction
+when the arms are moved upward and forward, or upward and backward.
+The length of the clavicle, as we have already said (p. 46), should be
+equal to that of the sternum without the xiphoid appendix.
+
+  [Illustration: FIG. 16.
+
+   RIGHT CLAVICLE: UPPER SURFACE.--1, body of clavicle;--2, 3,
+   inner or sternal extremity;--4, 5, outer or acromial extremity.]
+
+The _shoulder-blade_, or _scapula_, is a flat, triangular bone, and
+consists of a bony plate very thin at certain points, and thickened
+only along its borders. It is placed on the lateral and posterior
+aspect of the thorax, and corresponds at its upper border to the second
+rib: its lower end reaches to the seventh or eighth rib. It is attached
+by a joint called the _acromio-clavicular articulation_, which can be
+felt beneath the skin, to the external extremity of the clavicle. As
+this joint is the only ligamentous connection of the scapula with the
+trunk, the bone is capable of great freedom of movement.
+
+  [Illustration: FIG. 17.
+
+   SHOULDER-BLADE: POSTERIOR SURFACE.--1, supra-spinous fossa;--2,
+   infra-spinous fossa;--3, superior border with supra-scapular
+   notch (4);--5, external or axillary border with impression
+   for attachment (8) of the long head of the triceps;--6,
+   glenoid cavity;--7, inferior angle;--9, internal or vertebral
+   border;--10 and 11, spine of shoulder-blade extending into
+   acromion process (12);--14, coracoid process.]
+
+The shoulder-blade is described as possessing two surfaces, three
+borders, three processes, and three angles. The _posterior surface_,
+free and visible throughout its entire extent upon the mounted
+skeleton, is divided into two unequal portions--the upper one,
+the smaller (_supra-spinous fossa_) and the lower one, the larger
+(_infra-spinous fossa_)--by a bony crest, called the _spine of the
+scapula_ (10, 11, Fig. 17), which traverses the bone obliquely from
+within upwards and outwards. It becomes more and more prominent
+externally, and is afterwards prolonged into a free process, broad
+and flat, which forms the most elevated and external part of the
+skeleton of the shoulder (12, Fig. 17), and is known by the name of the
+_acromion process_ (ἃχρος, summit; ὦμος, the shoulder). It is on the
+internal or anterior border of this acromion process that the small
+oval facet is found, by which the scapula articulates with the outer
+extremity of the clavicle by the _acromio-clavicular_ articulation.
+The fossa above the spine of the scapula is the _supra-spinous
+fossa_ (1, Fig. 17), and the larger space below the spine is called
+the _infra-spinous fossa_ (2, Fig. 17). The _anterior surface_ of
+the scapula has received the name of the _subscapular fossa_. It is
+directed forwards and inwards, and is separated from the ribs and
+armpit by large muscles. It is but little visible in the articulated
+skeleton.
+
+Of the three borders of the scapula, one is _superior_ and horizontal;
+it is the shortest of the three. The second is internal and vertical,
+parallel to the series of spinous processes of the vertebræ; to this
+is given the name of the _vertebral border_. The third, or outer
+border, is oblique, and is directed downwards and backwards; it
+corresponds to the region of the armpit, and has received the name
+of the _axillary border_. It is particularly to be noticed that the
+vertebral border is thin; the axillary border, on the contrary, is
+thick, and presents towards its superior limit a rough space, just
+below the glenoid fossa, for the attachment of the long head of the
+triceps muscle (8, Fig. 17). The superior border is remarkable for the
+presence at its outer extremity of a stout process which projects at
+first upwards, and is afterwards bent outwards upon itself like a bent
+finger. It has been likened to the beak of a crow, and has received
+the name of the _coracoid process_ (κὸραξ, a crow; εἷδος, form). The
+coracoid process (14, Fig. 17) is placed in front and on the inner
+side of the acromion, and the two together form an arch over the
+shoulder-joint, called the _coraco-acromial arch_, which is completed
+by a fibrous band proceeding from one process to the other, and called
+the _coraco-acromial ligament_. The position of the coracoid process
+should be particularly noted in relation to the clavicle. It underlies
+the outer part of the clavicle, from which two important ligaments
+(_conoid and trapezoid ligaments_) descend to be attached to its upper
+surface. These ligaments serve the purpose of slinging the scapula
+up to the under surface of the clavicle. Of the three angles of the
+scapula, one only--the superior external angle, which is situated
+beneath the coraco-acromial arch--deserves a particular description; it
+is very thick, and becomes enlarged to form an articular surface (6,
+Fig. 17), which is directed outwards and forwards, and articulates with
+the head of the humerus. This surface is pear-shaped and is slightly
+hollowed out, and bears the name of the _glenoid cavity_. It is much
+less extensive than the articular head of the humerus, along with which
+it forms the shoulder-joint.
+
+In regard to the relative proportions of the scapula, it may be noted
+that the length of the vertebral border is equal to the length of the
+clavicle, and equal also to the distance which separates the scapulæ
+behind, when the vertebral borders are vertical, which is the case when
+the arms are hanging beside the body in a position of relaxation.
+
+The movements of the shoulder-blade, and their effects on external
+form, will be studied in relation to the articulation of the
+scapula with the humerus, the _scapulo-humeral_ articulation, or
+shoulder-joint. We must now pass on to describe the upper portion of
+the bone of the arm.
+
+  [Illustration: FIG. 18.
+
+   LEFT HUMERUS (anterior surface): 1, body of the bone;--2,
+   articular head;--3, anatomical neck;--4, great tuberosity;--5,
+   lesser tuberosity;--6, bicipital groove;--7, deltoid
+   impression;--11, capitellum;--12, trochlea;--13, external
+   supra-condyloid ridge;--14, condyles;--16, internal
+   supra-condyloid ridge;--17, coronoid fossa.]
+
+The arm bone, or _humerus_, is one of the long bones, and is
+composed of a shaft, prismatic or nearly cylindrical in form, and
+of two enlarged extremities, one inferior, which takes part in the
+articulation of the elbow; the other superior, which takes part in the
+articulation of the shoulder. We will only concern ourselves for the
+present with the superior extremity.
+
+_The superior extremity_ of the humerus is large and spherical. It is
+continuous with the body of the bone by a cylindrical neck, called
+the _surgical neck_ of the humerus. This extremity is traversed by
+a circular groove, oblique from above downwards, and from without
+inwards, called the _anatomical neck_ (3, Fig. 18). This is well
+marked, and divides the sphere into two parts; the one, situated above,
+and internal to the anatomical neck, is very regularly rounded, smooth,
+covered over by a layer of cartilage, and is called the _head_ of the
+humerus (2, Fig. 18); it is normally in contact with the glenoid
+cavity of the shoulder-blade, in which it glides in the movements of
+the arm; the other part of the head, situated below, and external to
+the anatomical neck, is rough, and divided into two tuberosities by
+a vertical groove, which is prolonged as far as the upper part of
+the body of the bone, and which, from its serving to accommodate the
+long tendon of the biceps, has received the name of the _bicipital
+groove_ (6, Fig. 18). The tuberosity situated on the outer side of the
+bicipital groove is large, and is called the _great tuberosity_ (4,
+Fig. 18); it presents three small surfaces which receive the insertions
+of the deep muscles of the shoulder--supraspinatus, infraspinatus, and
+teres minor muscles. The tuberosity situated on the front of the bone,
+and internal to the bicipital groove, is smaller. It is called the
+_small tuberosity_ of the humerus (5, Fig. 18), and gives attachment to
+one muscle only, the subscapularis.
+
+THE SHOULDER-JOINT.--The articulation of the shoulder, or
+_scapulo-humeral_ articulation, may serve as a type of articulations
+in general. It is necessary in each articulation to consider how the
+shapes of the bony surfaces in contact correspond to each other. From
+this we should be able to deduce the nature of the movements permitted
+by the articulation. It is also necessary to consider the disposition
+of the ligaments; that is to say, of the fibrous bands which proceed
+from one bone to the other, and from these we can deduce the limits of
+the movements of which the joint may be capable.
+
+The scapulo-humeral articulation is a ball-and-socket joint, formed by
+the glenoid cavity of the shoulder-blade and the head of the humerus.
+
+  [Illustration: FIG. 19.
+
+   LIGAMENTS OF SHOULDER, WITH SCAPULA, CLAVICLE, AND HUMERUS.--1,
+   Acromio-clavicular ligament;--2, coraco-clavicular ligament;--3,
+   coraco-acromial ligament;--4, supra-scapular ligament;--5,
+   capsule of shoulder-joint;--6, coraco-humeral ligament;--7,
+   tendon of biceps (long head).]
+
+Such an arrangement of surfaces in contact with one another permits the
+head to glide in all directions within the cavity, and consequently the
+upper limb can be moved in all directions: forwards; backwards; inwards
+(adduction); outwards (abduction); upwards and downwards. The head of
+the humerus can also be rotated on the glenoid cavity, either inwards
+or outwards.
+
+The ligamentous covering of the joint is formed by a fibrous capsule,
+which is attached on one side to the margin of the glenoid cavity, and
+on the other side to the anatomical neck of the humerus (5, Fig. 19).
+
+This ligamentous capsule is sufficiently loose to allow the head of the
+humerus great freedom of movement within the glenoid cavity, without
+any part of the capsule being put on the stretch, and thus stopping its
+movement. Thus the movement of the arm forwards is very extensive, as
+are those backwards and directly inwards, this last being checked only
+by the meeting of the arm with the lateral surface of the trunk. But
+the movement of abduction, or of elevation outwards, becomes difficult
+when the arm approaches the horizontal; here an arrangement comes into
+play which is of great importance, the study of which shows us that the
+upper limb, besides the mobility which belongs to the shoulder-joint
+proper (scapulo-humeral articulation), derives an increase of mobility
+from the articulations of the shoulder-blade with the clavicle, and of
+the clavicle with the sternum.
+
+When we apply a humerus to the glenoid fossa of the scapula in such
+a manner as to draw the arm outwards, we observe that at the moment
+when the humerus attains the horizontal position, the tuberosities
+touch the coraco-acromial arch which surmounts the glenoid cavity, and
+which is completed by the coraco-acromial ligament (3, Fig. 19); in
+the complete subject, in the living man, when the arm is elevated in
+carrying it outwards, the same effect of meeting and, so to speak, of
+contact between the tuberosities of the humerus and the acromial arch
+is produced, with this result--that the arm, once horizontal, is with
+difficulty raised higher by the simple play of the scapulo-humeral
+articulation--that is to say, by the gliding of the head of the humerus
+in the glenoid cavity. But now a new source of mobility is employed, a
+new articulation is brought into play--that of the acromio-clavicular
+joint. The entire scapula moves round the extremity of the clavicle;
+its inferior angle is carried forward; its external angle--that is
+to say, the glenoid cavity with the coraco-acromial arch--is carried
+upwards, and the movement of elevation of the arm is then continued by
+the play of the shoulder-blade.
+
+  [Illustration: FIG. 20.
+
+  OUTLINE OF SHOULDER WITH THE ARM RAISED.]
+
+As the result is an important change of shape in the shoulder, we ought
+to particularly examine the shoulder in the region of the back, upon
+a model in which the arm is raised above the horizontal position. The
+point of the shoulder is raised, and as this elevation is accompanied
+by a movement of the shoulder-blade, the vertebral border of this bone
+does not remain parallel to the spinal column, but while it approaches
+closer to it at its upper end, it is drawn further away at its lower
+end, and is obliquely directed from above downwards and outwards (Fig.
+20). The inferior angle becomes prominent in the lower part of the
+armpit, as we may observe in a subject with the arms folded, and shows
+in a striking manner on a dead crucified body. If the elevation of the
+arm approaches the vertical, the vertebral border of the shoulder-blade
+has a tendency to become horizontal, and we observe this change of
+movement in the model when the bone is seen along the posterior surface
+of the shoulder and the back, and we should scarcely recognise at first
+the appearances presented as those we are accustomed to study when it
+occupies its ordinary situation in the skeleton.
+
+But when the arm is elevated vertically, so that it comes in contact
+with the side of the head, movement takes place not only at the
+scapulo-humeral and at the acromio-clavicular joints, but also at
+the articulation of the internal extremity of the clavicle with the
+sternum. In that case, in fact, the whole of the shoulder is raised
+upwards (by the superior fibres of the trapezius muscle), and the
+clavicle represents the arm of the lever by which this movement
+is accomplished, while the sterno-clavicular articulation is the
+hinge. Thus we see the clavicle is changed in its direction, from
+the horizontal, to become oblique upwards and outwards--that is, its
+external extremity is raised and carried a little backwards.
+
+The clavicle plays a very important part in the movements of the
+upper limb. This explains why it is found specially developed
+in those animals whose fore-limbs possess the most specialised
+movements--flight, digging, burrowing, striking, or hugging--such as
+man, the monkey, the bat, the tiger, the mole, etc.; while in those
+quadrupedal animals which, like the horse, use their fore-limbs for
+progression only, and in which movements occur only in a plane parallel
+to that of the body, there is not a trace of clavicle. The part which
+the clavicle takes in the movements of the arm explains also why the
+bone presents a variable size in different individuals. It is stronger
+in the male than in the female; stronger in the working man than in
+the student; stronger, finally, on the right side than the left, from
+the habit of using the right arm for the most part in those actions
+which demand strength and skill. In the left-handed, it is the left
+clavicle that is stronger than the right. In a word, this bone is,
+like all the other parts of the skeleton, stronger in proportion as
+it takes part in active and frequently repeated movements. Thus the
+breadth of the shoulders is one of the characteristics of athletes; and
+it is to the strength of the bony structure formed by the clavicle and
+shoulder-blade, sustained by the first ribs, that the superior portion
+of the thorax owes its characteristic aspect.
+
+Owing to the presence of the shoulder girdle (scapula and clavicle)
+the thoracic cage does not present much of the form of a cone at its
+upper end, or summit; indeed, this region becomes broader in a lateral
+direction as the clavicle is more developed. It will be enough to
+contrast the region of the thorax in man with that of such animals as
+the dog or the horse, which, owing to the absence of a clavicle, have
+a thorax transversely flattened in the region of the shoulders, and
+consequently the shoulder-blades more closely applied upon the sides of
+the thoracic cage.
+
+This is the proper place to discuss the dimensions and proportions of
+the shoulder; but, as this study consists entirely of a comparison of
+the transverse diameters of the shoulders with the transverse diameters
+of the hips, it is better to defer it till after the description of the
+pelvis.
+
+
+
+
+                              CHAPTER VI.
+
+                     THE HUMERUS AND ELBOW-JOINT.
+
+   The bony structure of the arm and elbow.--The shaft of the
+   humerus.--The axis of the arm and forearm.--Spiral groove of the
+   humerus; the inferior extremity of the humerus; the trochlea
+   and capitellum; the external and internal supra-condyloid
+   ridges.--The superior extremities of the two bones of the
+   forearm; the ulna (sigmoid cavities, olecranon process, coronoid
+   process); radius (head, neck).--The articulation of the elbow;
+   transverse hinge joint.--Movements of flexion and extension;
+   lateral movements.--The external form of the elbow; prominence
+   of the internal condyle and olecranon process.
+
+
+The _shaft of the humerus_ is prismatic in its upper and middle parts,
+and flattened from front to back at its lower extremity. Covered over
+by thick muscles, its outward shape has for us but little interest;
+it is necessary only to note with regard to its direction that, when
+the arm is hanging down, the humerus is not altogether vertical, but
+is tilted slightly downwards and inwards. We shall see that the axis
+of the bones of the forearm is oblique in the opposite direction; for
+this reason the arm and forearm form at the elbow a very obtuse angle,
+looking outwards (Figs. 24, 26).
+
+Among the details to be noted upon the shaft of the humerus, the
+_bicipital groove_ is worthy of remark. This vertical groove, which
+separates the great from the small tuberosity on the front of the
+humerus at its upper end (Fig. 18), is prolonged along the shaft of the
+bone, and presents an internal lip slightly prominent, and an external
+or anterior lip which is much more marked, which gives insertion to
+the broad tendon of the great pectoral muscle. At the line of junction
+of the superior with the middle third of the bone, this lip forms the
+anterior margin of a rough surface shaped like the letter =V= (7, Fig.
+18), of which the angle looks downwards, and which, giving insertion to
+the deltoid muscle, has received the name of the _deltoid impression_.
+On the back of the humerus is another groove, broad and shallow, called
+the _spiral groove_ of the humerus, which passes downwards and outwards
+along the shaft of the bone behind and below the deltoid impression.
+
+The inferior extremity of the humerus deserves to be studied in detail,
+as its shape gives the key to the movements of the elbow-joint, and
+explains at the same time several features of the region to be seen
+in the living model. This extremity is flattened from front to back,
+and is enlarged into a broad surface which is partly articular, partly
+non-articular. In the middle are two important articular prominences,
+smooth and covered with cartilage. Of these the internal portion is
+called the _trochlea_ (_trochlea_, pulley). It possesses a groove and
+two unequal marginal ridges. The internal ridge is more prominent and
+descends lower than the external one. The other projection (11, Fig.
+18), which is situated on the outer side of the trochlea, is rounded
+in shape, and receives the name of the _radial head_, or _capitellum_.
+It is only obvious when the humerus is looked at from the front or
+from below: in other words, it does not appear (like the trochlear
+surface) on the posterior aspect of the lower end of the bone. This
+surface articulates with the upper end of the radius. There are three
+depressions, or fossæ, to be seen in relation to the articular surfaces
+of the lower end of the humerus. On the front of the bone, just above
+the trochlea and capitellum, are two, which receive the bones of the
+forearm during flexion of the limb: the _coronoid fossa_ (for the
+coronoid process of the ulna), above the trochlear surface, and the
+_radial depression_ for the head of the radius, much shallower, and
+placed above the capitellum. On the back, above the trochlear surface,
+is the _olecranon fossa_, into which the olecranon process is received
+during extension of the forearm.
+
+The lateral portions of the inferior extremity of the humerus are
+formed by rough, non-articular projections which give attachment to
+muscles and ligaments, and are known respectively as the _external
+condyle_ and the _internal condyle_ of the humerus (14, 14, Fig. 18).
+Above each condyle is a well-marked bony ridge, which is called the
+_supra-condyloid ridge_ (external or internal) (13, 13, Fig. 18).
+
+The lower end of the humerus articulates with the upper extremities
+of the bones of the forearm; and we will next proceed to study the
+formation of these extremities in order to understand the movements of
+the elbow-joint and the form of the region.
+
+The forearm is formed of two bones (Fig. 21), which, when the upper
+limb is hanging beside the body, the palmar surface of the hand being
+turned forwards, are placed parallel to each other--one on the outer,
+one on the inner side. The inner bone (1, Fig. 21) is called the
+_ulna_, or _cubitus_, and it is that which by its upper extremity
+(_olecranon_) forms the bony prominence of the elbow; the outer bone
+(10, Fig. 21) is called the _radius_ (from the Latin _radius_, a spoke
+of a wheel), and it is by this bone chiefly that the bones of the wrist
+and hand are carried. For the present we will describe only the upper
+extremities of these two bones (Figs. 21 and 22).
+
+  [Illustration: FIG. 21.
+
+   THE BONES OF THE FOREARM (anterior surface): 1, shaft of
+   ulna;--2, great sigmoid cavity;--3, lesser sigmoid cavity
+   with head of radius;--4, olecranon;--5, coronoid process;--7,
+   interosseous space;--8, inferior extremity of ulna with
+   styloid process (9);--10, shaft of radius;--11, its head;--12,
+   neck;--13, tubercle for biceps;--14, impression for pronator
+   teres muscle;--15, inferior extremity of radius with styloid
+   process (16).]
+
+The superior extremity of the ulna presents two processes and two
+articular cavities. The cavities are the _greater_ and _lesser_ sigmoid
+cavities; the processes are the coronoid and olecranon processes. The
+bone articulates with the pulley or trochlea of the humerus by means
+of the _great sigmoid cavity_, and with the margin of the head of the
+radius by the _lesser sigmoid cavity_. The greater sigmoid cavity
+(2, Fig. 21) presents in its centre a ridge prominent from before
+backwards, which corresponds to the groove in the trochlea of the
+humerus. Below and in front, the great sigmoid cavity is formed (5,
+Fig. 21) by a bony prominence called the _coronoid process_ (compared
+to the beak of a crow: κορώνη, a crow; εἶδος, form), which is lodged
+in the coronoid fossa of the humerus in flexion of the forearm (17,
+Fig. 18). Above and behind, the great sigmoid cavity is formed by
+the _olecranon process_ (ὠλενη, the elbow; κάρηνον, the head), a
+large square projection (4, Fig. 21), which constitutes the prominent
+point of the elbow, and which accentuates in a high degree the form
+of the forearm during flexion. During extension of the forearm the
+olecranon process is lodged partly in the _olecranon fossa_ of the
+humerus (4, Fig. 23). The lesser sigmoid cavity of the ulna is a small
+concave surface placed on the outer side of the coronoid process for
+articulation with the margin of the head of the radius.
+
+  [Illustration: FIG. 22.
+
+   FIGURE OF THE ELBOW JOINT, RIGHT SIDE (anterior view):--1,
+   inferior portion of shaft of humerus;--2, ulna;--3, radius;--4,
+   external condyle;--5, internal condyle;--6, capitellum;--7 and
+   8, trochlea;--9, coronoid fossa;--10, coronoid process;--11,
+   head of radius.]
+
+The superior extremity of the radius forms a small discoidal head
+(11, Fig. 21) attached by a narrow neck to the body of the bone; this
+head is flattened at the top and hollowed out to articulate with the
+_capitellum_ of the humerus (Fig. 22). The margin of the head of the
+radius revolves in the lesser sigmoid cavity of the ulna.
+
+We see, then, that the articular surfaces of the elbow are formed on
+the humerus (6, 7, 8, Fig. 22) by a transverse series of projections
+(the trochlea and capitellum), and on the bones of the forearm by a
+series of depressions moulded on these projections, so that the whole
+describes a movement similar to that between two cog-wheels (Fig.
+22), a species of transverse hinge. Thus it is easy to understand,
+_à priori_, how this disposition of the parts does not permit of
+any lateral displacement of the bones, or transverse movement; the
+movements forward and backward are, in fact, the only kind possible
+in the elbow-joint. The forward movement--that is to say, that by
+which the anterior surface of the forearm is brought near the anterior
+surface of the arm--constitutes _flexion_ of the forearm. The movement
+in the opposite direction constitutes _extension_.
+
+The disposition of the ligaments--that is, of the fibrous bands or
+articular capsule which fasten the bones together--modifies very
+slightly the mechanism we have just deduced from the shape of the
+articular surfaces; in fact, this capsule is formed on the inner and
+outer surfaces by ligamentous fibres, very dense and short, called the
+lateral ligaments, which prevent all lateral movement. On the other
+hand, the anterior and posterior portions of the capsule are loose,
+so as not to offer any opposition to the movements of flexion and
+extension. The only limit to these movements is that resulting from
+the bony projections of the ulna coming in contact with the humerus.
+Thus, the movement of flexion can be prolonged until the coronoid
+process arrives at the coronoid fossa and touches the bottom of that
+cavity; then the fleshy masses of the forearm come into contact with
+the anterior surface of the arm, especially if the model is muscular,
+and flexion is no longer possible. The movement of extension, on the
+contrary, has a limit which it is important to state precisely,
+resulting from the beak of the olecranon touching the bottom of the
+olecranon fossa (Fig. 23); this is produced when the forearm has
+attained, in the movement of extension, that situation which brings its
+own axis into direct line with that of the arm. The extension of the
+elbow cannot therefore exceed the degree which brings the humerus and
+forearm into the same plane; that is to say, the forearm can never make
+with the arm an angle facing backwards.
+
+  [Illustration: FIG. 23.
+
+   ANTERO-POSTERIOR SECTION OF THE ELBOW (through the ulna):--1,
+   humerus;--2, ulna;--3, coronoid fossa;--4, olecranoid fossa;--5,
+   olecranon;--6, coronoid process;--7, section of trochlea.]
+
+By comparing the particulars of the mechanism of the elbow with that
+which we have previously seen of the mechanism of the scapulo-humeral
+articulation, it will be easy to understand how we may, from the
+study of the articular surfaces and ligaments, learn the laws of the
+mechanism of joints. For example, the head of the humerus received into
+a single concavity may allow to the arm every kind of movement; in the
+same way the arrangement of a hinge-joint, with a series of projections
+and depressions, fitted one to the other in a transverse line, renders
+possible in the elbow-joint only the movements of flexion and extension.
+
+In regard to external form, we learn the following facts from a
+knowledge of the bones which form the elbow-joint.
+
+1. With respect to the angle which the forearm makes with the arm, if
+we examine it either upon the skeleton or upon the living subject, the
+upper limb hanging beside the body, with the palm of the hand turned
+forward, it is seen that the humerus (page 67) is slightly oblique
+from above downwards and inwards, while the two bones of the forearm
+are directed obliquely in the opposite direction--that is, from above
+downwards and outwards. In other words, the bones of the arm and
+forearm form at their point of junction--that is, at the level of the
+elbow--an _angle_ the base of which looks outwards and the apex
+inwards. This angle only appears in extension of the limb, and is due
+to the twisted and tilted form of the trochlear surface of the humerus.
+
+  [Illustration: FIG. 24.
+
+  OUTLINE OF UPPER LIMB (front view)]
+
+2. Concerning the bony prominences which are seen beneath the skin
+at the elbow (Fig. 24), after studying these osseous structures, we
+should be able to recognise upon the living model those details of
+the figure which correspond to the four bony points--namely, the
+coronoid process in front, the olecranon behind, the external condyle
+on the outer side, and the internal condyle on the inner side. The
+coronoid process, covered by muscles, is so buried in the surrounding
+structure that it does not show externally. It is much the same also
+with the external condyle, as this projection, not very prominent
+in the skeleton, disappears completely in the living subject, since
+this external condyle is situated at the bottom of the angle facing
+outwards which the forearm makes with the arm, and the mouth of this
+angle is filled up by the external muscles of the forearm (especially
+the brachio-radialis, or supinator longus), which take their origin
+from the external border of the humerus. The external condyle and the
+external supra-condyloid ridge can be felt beneath the skin; and the
+former occupies a depression at the back of the elbow on its outer side
+in extension of the forearm.
+
+On the other hand, the internal condyle, supra-condyloid ridge, and
+the olecranon process always show clearly beneath the skin, and the
+olecranon forms that projection, commonly called the _point of the
+elbow_, which is so prominent behind during flexion of the forearm,
+and which follows the movements of the forearm, seeming to rise
+towards the arm during the extension of the forearm, and to descend
+during flexion. The internal condyle projects as the apex of the angle
+formed by the axis of the forearm with that of the arm (Fig. 26, page
+81); this is a fixed point placed a little above the line of the
+elbow-joint, which is useful in measurements.
+
+There is one detail which we must not forget at this stage; in
+comparing the length of the forearm with that of the arm the olecranon
+must be excluded, as it projects above the lower end of the humerus; on
+the other hand, the internal condyle should rather be chosen as a fixed
+point from which measurements may be taken.
+
+
+
+
+                             CHAPTER VII.
+
+          SKELETON OF THE FOREARM: PRONATION AND SUPINATION.
+
+   The bones of the forearm; ulna and radius.--The lower
+   extremities of these bones; their styloid processes; triangular
+   fibro-cartilage of the wrist.--_Pronation_ and _supination_:
+   change of form and direction of the forearm: and position of the
+   hand.--Prominences of the wrist (styloid processes); the angle
+   which the axis of the hand makes with that of the forearm.
+
+
+We have already examined the upper ends of the bones of the forearm
+(radius and ulna) in relation to the elbow-joint. We have still to
+examine their shafts and lower extremities; and in this chapter we will
+continue their description, and study the movements of the two bones,
+and the relation which they bear to the wrist-joint and the hand. In a
+state of rest the two bones lie parallel, the radius externally, and
+the ulna internally, separated except at their extremities by a wide
+interosseous space.
+
+A superficial glance at the bony structure of the forearm (Fig. 21,
+p. 70) suffices to show that the two bones which compose it offer in
+many respects a striking contrast to each other. They differ first
+of all in the relative position which they hold in the forearm. The
+inner bone is the ulna, which extends upwards beyond the radius by
+reason of the length of the olecranon process. On the other hand, in
+the neighbourhood of the wrist, the radius extends beyond the ulna and
+descends below it. We should also note at the outset that the radius,
+descending below the ulna, is found to be the only bone of the forearm
+which articulates directly with the hand and forms the wrist-joint, or
+_radio-carpal_ articulation. The lower end of the ulna is separated
+by a wide space from the carpus (_cuneiform_ bone), which is filled
+up in the living subject by the _triangular fibro-cartilage_ of the
+wrist-joint. As regards size also these bones present a contrast; the
+ulna is thick and bulky in its upper part, but becomes thinner as it
+descends, and its inferior extremity is slender (Fig. 21); the radius,
+on the other hand, is relatively small at its upper end, and increases
+in size below, so that its inferior extremity, articulating with the
+hand, forms a large bony surface.
+
+We need not enter into minute details regarding the shape of the shafts
+of the two bones.
+
+They are regularly prismatic in form. At the upper end of the shaft
+of the radius, immediately below the neck, is a tuberosity (13, Fig.
+21), directed forwards and inwards, which gives insertion to the tendon
+of the biceps (_bicipital tubercle_). From this tuberosity an oblique
+line passes downwards and outwards, and terminates upon the middle part
+of the external surface of the bone in a rough space (14, Fig. 21)
+called the _impression for the pronator radii teres_, because it gives
+insertion to the muscle of that name.
+
+With regard to the shaft of the ulna, we need only notice that its
+posterior border is subcutaneous in its whole extent, and can be felt
+beneath the skin from the elbow to the wrist.
+
+The lower end of the radius is enlarged and massive. On its inner side
+it articulates with the ulna. Externally it is prolonged downwards as
+the _styloid process_, which forms a well-marked prominence at the
+outer side of the wrist. The inferior surface is hollowed into a smooth
+triangular surface for articulation with two of the bones of the wrist
+(_scaphoid_ and _semi-lunar_).
+
+The inferior extremity of the ulna is much smaller. It presents a
+rounded head (8, Fig. 21), which articulates externally with the
+radius, and below with the _triangular fibro-cartilage of the wrist_,
+which intervenes between the ulna and the carpus, and fills the gap
+between that bone and the cuneiform bone. The ulna is prolonged on its
+inner side and behind into a _styloid process_ which forms the internal
+prominence of the wrist. We have already said that the inferior
+extremity of the ulna does not descend as low as the corresponding
+portion of the radius; the triangular fibro-cartilage, which lies below
+the ulna, proceeds from the external border of the inferior extremity
+of the radius to the base of the styloid process of the ulna; the
+bones of the wrist articulate with the radius and with this triangular
+fibro-cartilage, so that the ulna does not take part directly in the
+articulation of the forearm with the hand (Fig. 28, page 88). The
+relation of the ulna to the wrist-bones is well shown in a radiograph
+of the hand, in which the space between the bones at the inner side
+of the wrist is clearly seen (Fig. 25). This arrangement is of prime
+importance, as will be seen later, in the movements of the wrist. On
+account of this space between the ulna and the carpus, the movement
+of _adduction_ (drawing inwards of the hand) is much freer and more
+extensive than _abduction_.
+
+  [Illustration: FIG. 25.
+
+   THE HAND AND WRIST: From a radiograph taken specially for this
+   work by Dr. Thurstan Holland, Liverpool.]
+
+  [Illustration: FIG. 26.
+
+   RIGHT FOREARM IN SUPINATION (the radius and radial half of the
+   hand are shaded by oblique lines): the radius is parallel to the
+   ulna.]
+
+  [Illustration: FIG. 27.
+
+   THE RIGHT FOREARM IN PRONATION: the radius (shaded) crosses the
+   ulna, and the radial half of hand (shaded) is placed on the
+   inner side.]
+
+Up to the present we have considered the two bones of the arm as
+placed parallel side by side, and separated by a comparatively broad
+interval, called the _interosseous space_ (7, Fig. 21). In fact, they
+are so placed, when the arm is hanging beside the body, in a state of
+rest, with the palm of the hand directed forwards (Fig. 26), or placed
+on a flat surface, palm upwards; the hand is then lying on its back,
+and this position we call _supination_ (_supinus_, lying on the back).
+But the hand may be changed in position, turned round so that its
+posterior surface is directed forward (Fig. 27), or, if the forearm be
+placed on a flat surface, the back of the hand is turned upwards. In
+this new position, when the hand lies on its palmar aspect, we speak
+of it as being in the position of _pronation_ (_pronus_, lying on the
+belly).
+
+This change from supination to pronation is accomplished by a change in
+the relations of the bones of the forearm to one another. They cease
+to be parallel when the hand is prone, and cross each other; but the
+two bones do not move similarly in this action; one of them, the ulna,
+practically remains fixed; the other, the radius, changes its position
+so as to cross it. On examining the points of contact between the
+radius and ulna--namely, the superior and inferior articulations of
+these two bones--we see that the _superior radio-ulnar articulation_ is
+formed by the circumference of the head of the radius received within
+the cavity (_lesser sigmoid cavity_), situated on the outer surface
+of the coronoid process of the ulna; whilst the _inferior radio-ulnar
+articulation_ is formed by a sigmoid cavity situated on the internal
+surface of the inferior extremity of the radius, which articulates with
+the circumference of the head of the ulna.
+
+The axis of movement may be represented by a line drawn through the
+centres of the upper end of the radius and the lower end of the ulna.
+In the superior radio-ulnar articulation, the head of the radius
+revolves on its own axis and turns in the sigmoid cavity of the ulna;
+the superior extremity of the radius itself does not change its
+position; in the inferior radio-ulnar articulation, on the contrary,
+the radius moves round the head of the ulna, as a wheel round its axle.
+
+These considerations of articular mechanism may be best understood
+by examining a portion of the skeleton containing the bones of the
+forearm, which, as is usual in articulated preparations, are connected
+together by metallic bands that permit the normal movements. In
+causing the hand to pass from supination to pronation, we see that
+it is necessary to bring the shaft of the radius across that of the
+ulna in such a manner that while the upper end of the radius still
+remains on the outer side, its lower end is entirely altered in
+position, and is carried to the inner side of the ulna (Figs. 26 and
+27). In accomplishing this movement, we perceive that the hand, which
+articulates only with the radius, must follow the movement of this
+bone, so that the thumb or radial border of the hand must change from
+the outer to the inner side; the palm of the hand, which in supination
+is directed forwards, is turned backwards in pronation, and it is this
+movement of the radius on the ulna which constitutes the passage from
+supination (Fig. 26) to pronation (Fig. 27).
+
+The general form of the forearm, irrespective of the details which
+we shall explain later, regarding the configuration of the muscles,
+depends directly on the position of these bones, and is changed
+according as they are parallel or crossed. When the hand is supinated
+(Fig. 26), the radius being then placed parallel to the ulna and
+separated from it by a large interosseous space, the form of the
+forearm is that of the segment of a limb presenting two borders--an
+external, or radial, and an internal, or ulnar--and two surfaces, one
+anterior, the other posterior. The forearm, in a word, is slightly
+flattened from front to back, because the bones are parallel to each
+other. But when, from the position of supination, the hand passes to
+that of pronation, the two bones cross each other and come in contact,
+and the interosseous space practically disappears (Fig. 27). The radius
+and ulna, taken together, form a single mass, which may be compared
+to that which two rods assume, placed at first parallel at a certain
+distance from each other, and which afterwards cross and come into
+direct contact. Thus in pronation the shape of the forearm becomes
+completely changed, especially in its lower two-thirds. Instead of a
+segment of a limb with two surfaces and two borders, it represents a
+segment rounded and almost cylindrical in its middle part; in complete
+supination, only the inferior part (wrist) and the superior part (bend
+of the elbow) preserve the form flattened from front to back.
+
+Artists are usually not sufficiently imbued with these important facts;
+they are inclined to believe that if a figure has been represented with
+the forearm in a position of supination, and that for some reason this
+attitude has been changed to that of pronation, it is enough to change
+the hand and wrist alone, without altering the model of the forearm in
+any other detail. On the other hand, the form of the forearm throughout
+its entire extent and particularly in the middle part, undergoes a
+change when the hand passes from supination to pronation, and the
+reverse; and this fact will be still more evident when, in studying
+the muscles of the region, we see that their direction is completely
+altered, and this also helps to modify the shape of the limb.
+
+In the movements of pronation and supination, the forearm changes
+not only in form, but also in direction. We have previously seen
+that when the radius and ulna are placed parallel one with the other
+(supination), the axis of the forearm makes with that of the arm an
+angle opening outwards. We may again express this fact by saying that
+if in this case we prolong the axis of the humerus downwards (see the
+dotted line in Fig. 26), this axis falls internal to the head (inferior
+extremity) of the ulna, and consequently lies well to the inner side of
+the radius and interosseous space. But in pronation, the result is that
+when the radius crosses the ulna at its centre, and is placed internal
+to it at its lower end, the two crossed bones of the forearm, taken
+together, make a continuous line with the humerus, the angle at the
+inner side of the elbow disappears, and the axis of the arm and that of
+the forearm are almost in the same straight line (Fig. 27).
+
+In order to make the best use of the various details of the bony
+structures which we have been studying in their application to outward
+form we will, before commencing the study of the hand, mark once more
+the prominences which occur at the lower ends of the radius and ulna at
+the level of the wrist. Of these two projections, which are to the hand
+what the ankle-bones, or malleoli, are to the feet, one is external,
+formed by the styloid process of the radius (16, Fig. 21), the other is
+internal, and is formed by the head of the ulna and its styloid process
+(9, Fig. 21).
+
+The styloid process of the radius is situated much lower than the
+styloid process of the ulna.
+
+This position of the bones we may easily verify upon ourselves, without
+a skeleton, by clasping with the thumb and index-finger of one hand
+the wrist of the other; we then perceive that the radius descends much
+lower than the ulna (Fig. 21). Hence the articular line of the forearm
+with the hand is obliquely directed from above downwards and outwards
+(the hand being supinated). So that the hand is articulated with the
+forearm at an angle, due to the downward prolongation of the lower
+end of the radius: a position which, along with the presence of the
+articular fibro-cartilage of the wrist, is responsible for the more
+extensive capacity for adduction than abduction of the hand at the
+wrist-joint.
+
+In the extended and supine position of the limb the junction of the arm
+and the forearm forms an angle opening outwards; that of the forearm
+and hand forms an angle opening inwards.
+
+
+
+
+                             CHAPTER VIII.
+
+               THE HAND.--PROPORTIONS OF THE UPPER LIMB
+
+   The bony structure of the hand.--The wrist, or carpus; eight
+   bones in two rows, superior and inferior.--The radio-carpal
+   articulation, or wrist-joint.--Carpal joints.--The form of the
+   wrist during flexion.--The palm of the hand, or metacarpus;
+   metacarpal bones; their relative lengths (form of the
+   fist).--Carpo-metacarpal articulations; the articulation of
+   the thumb.--The fingers, or phalanges.--Articulations of the
+   phalanges; their movements.--Proportions of the upper limb: the
+   arms extended (the square figure of the ancients); the hand as
+   a common measure; the middle finger and the Egyptian Canon of
+   Charles Blanc.--Brachial index.
+
+
+The hand is composed of three parts: the wrist, the palm, and the
+fingers. The bony structure of the wrist is formed by the _carpus_,
+that of the palm by the _metacarpus_ (μετὰ, below; καρπὸς, the wrist);
+the fingers are formed by small bones called _phalanges_ (Fig. 25, page
+80).
+
+As the carpus is almost completely hidden by soft parts, fibrous and
+tendinous, we shall first proceed to enumerate the bones which compose
+it, and show their articulations.
+
+Notwithstanding its small compass, the carpus is made up of not
+less than eight bones, which are placed in two transverse rows, one
+_superior_, or _brachial_ (next the forearm), the other _inferior_, or
+_metacarpal_ (next the metacarpus).
+
+The bones of the two rows are arranged as follows, enumerating them
+in order from without inwards--that is, from the radial to the
+ulnar border of the wrist:--The four bones of the first row are:
+the _scaphoid_ (S, Fig. 28), named from the cavity on the inferior
+surface being compared to a boat (_σκάφη_, a boat; _εἶδος_, form);
+the _semi-lunar_ (L, Fig. 28); the _cuneiform_ (C, Fig. 28) (whose
+names indicate their shape); and the _pisiform_ (P, Fig. 28), which,
+small and rounded, is placed on the anterior surface of the cuneiform
+bone, and articulates with it alone (Fig. 29). The four bones of the
+second row, still naming them from without inwards, are (Fig. 28):
+_trapezium_, _trapezoid_, _os magnum_, and _unciform_ bones (_uncus_, a
+hook).
+
+  [Illustration: FIG. 28.
+
+   THE BONY STRUCTURE OF THE WRIST (dorsal surface): R, radius;--U,
+   ulna;--F, triangular fibro-cartilage;--S, scaphoid;--L,
+   semi-lunar;--C, cuneiform;--P, pisiform;--T, trapezium;--T,
+   trapezoid;--M, os magnum;--U, unciform.--Below the carpus: 1, 2,
+   3, 4, 5, the five metacarpal bones counting from that of thumb
+   (1).]
+
+An examination of the bony structure of the carpus as a whole shows
+that the anterior or palmar surface presents the form of a vertical
+groove, limited on the inner side by the forward projections of the
+pisiform and unciform bones, and on the outer side by the projections
+of the scaphoid and trapezium. This groove is formed into a canal by
+means of a broad fibrous band (the _anterior annular ligament_ of
+the wrist), which passes like a bridge across the wrist between the
+prominences just named. Beneath this bridge, and in the canal thus
+formed, pass the tendons of the flexor muscles of the fingers, the
+fleshy bellies of which occupy the forearm, while their tendinous
+insertions are attached to the phalanges. This explains the fact that
+these tendons, seen at the lower part of the forearm, are not visible
+superficially during their passage into the palm of the hand.
+
+_The Wrist-Joint._--The _radio-carpal_ joint is formed by the convex
+upper surface of the carpus, constituted by the scaphoid, semi-lunar,
+and cuneiform bones, articulating with the lower end of the radius and
+the fibro-cartilage of the wrist (which lies below the ulna). This
+articulation permits movements of the hand in four directions: forwards
+and backwards (flexion and extension); outwards and inwards (abduction
+and adduction).
+
+_Inter-carpal Joint._--The several carpal bones glide upon one another:
+and there is only a limited movement possible of flexion and extension
+between the three named bones of the first row (scaphoid, semi-lunar,
+and cuneiform) and the four bones of the second row; but lateral
+movements are very limited and practically absent.
+
+It is thus obvious that the movements of flexion and extension of the
+hand at the wrist-joint are extensive, and amount almost to a right
+angle, both before and behind, the mobility of the radio-carpal and
+inter-carpal articulations aiding each other in these movements; on
+the contrary, the lateral movements of the wrist are more limited, as
+they are confined to the radio-carpal articulation, and are restricted
+on the outer side (abduction) by the downward projection of the lower
+end of the radius. Adduction is a much more powerful movement, rendered
+freer by the presence of the triangular fibro-cartilage of the wrist,
+and the separation of the ulna and the cuneiform bones. It should also
+be noted that in flexion of the hand, when it forms a right angle with
+the forearm, the posterior surface of the wrist does not present an
+abrupt curve, but rather a rounded form; the convexity being made up
+of two series of articulations, the radio-carpal and the inter-carpal
+articulations.
+
+  [Illustration: FIG. 29.
+
+   BONY STRUCTURE OF HAND (anterior or palm surface).--1, 2, 3,
+   and 4, the four bones of superior row of carpus:--5, 7, 8, and
+   9, the four bones of inferior row;--10, 10, the five metacarpal
+   bones;--11, 11, the first phalanges;--12, 12, the second
+   phalanges;--13, 13, the third phalanges;--14 and 15, the two
+   phalanges of the thumb.]
+
+The _metacarpus_ (Fig. 29), or skeleton of the palm of the hand,
+is composed of five slender, long bones--the five metacarpal
+bones--separated from each other by _interosseous_ spaces. Each
+metacarpal bone, like the other long bones, is composed of a shaft and
+two extremities. The shaft is more or less prismatic and triangular;
+the upper or carpal extremity is cuboid, or wedge-shaped; the lower or
+digital end is rounded to articulate with the first bone of the finger.
+The five bones are distinguished by the names, first, second, third,
+fourth, and fifth metacarpal, counting from the thumb to the little
+finger; or, again, by the name of the finger to which they correspond
+(as the metacarpal bone of the thumb, index finger, etc.). The
+first metacarpal bone, or that of the thumb, is the shortest, and is
+remarkable for characteristics to which reference will be made later;
+the second, or metacarpal bone of the index finger, and the third, or
+that of the middle finger, are the longest. The third is generally
+longer than the second, so that a line passing through the heads of
+the series of metacarpal bones describes a curve with its convexity
+downwards, of which the most prominent part corresponds to the head
+of the third metacarpal bone. When the hand is firmly closed, and the
+fingers bent in the palm, it is the head of the third metacarpal bone
+which forms the most prominent part of the fist.
+
+The metacarpal bones articulate with the carpus by their upper
+extremities, or bases. In these articulations a very different
+arrangement is found for the first metacarpal bone when compared with
+that of the other four.
+
+The articulation of the metacarpal bone of the thumb is formed by a
+saddle-shaped facet on the trapezium, concave from side to side, and
+convex from before backwards, and a corresponding facet at the base
+of the first metacarpal bone. It results, then, that as the rider
+can move himself on his saddle forwards and backwards, and to either
+side, so the metacarpal bone of the thumb is equally movable in all
+directions, and can accomplish the movement of circumduction, by
+which the extremity of the thumb describes a circle. This mobility
+permits the thumb to be separated from the other fingers, or to be
+drawn across the hand, or to touch the tips of the other fingers.
+This last is called the _movement of opposition_ of the thumb,
+and it is owing to this property that the thumb possesses of opposing
+itself to the fingers that the hand of man forms such a wonderful
+organ for prehension and for performing the most delicate and refined
+movements. The articulation of the trapezium and metacarpal bone, which
+is the source of these movements, thus deserves particular mention.
+The articular surfaces of the two bones are attached to each other by
+an articular capsule sufficiently loose to allow all the movements of
+which the first metacarpal bone is capable.
+
+On the other hand, the articulations of the metacarpal bones of the
+four other fingers do not present any such mobility. In fact, whilst
+the base of the first metacarpal bone is free, without being connected
+with that of the second, the bases of the other metacarpal bones are
+in contact with each other by their lateral surfaces, and are united
+by dorsal, palmar, and interosseous ligaments. Again, the transverse
+line of union between the second row of the carpus and the base of
+these metacarpal bones (carpo-metacarpal line) is irregular, the carpus
+and metacarpus being dovetailed into each other, especially at the
+level of the second and third metacarpals, by reason of the projection
+upwards of the second metacarpal bone, and the projection downwards of
+the os magnum (Fig. 29). The carpus and the four last metacarpal bones
+therefore form a series of joints, of which the parts are only slightly
+movable one on the other, giving a certain elasticity to the whole.
+The effects of pressure or sudden shock are avoided by the presence of
+numerous parts united in such a manner as to glide one on the other, at
+the same time not presenting any independent mobility.
+
+The fingers are formed of a series of slender bones placed end to end,
+and termed _phalanges_. Each finger has three phalanges, except the
+thumb, which has only two. We distinguish the rows of phalanges by the
+names of the first, second, or third, counting from the base to the
+free extremity of the fingers; and we give the name of _ungual_ phalanx
+to the last because it supports the nail. These phalanges, like the
+other long bones, are made up of a shaft and two extremities. The shaft
+is semi-cylindrical in shape, rounded behind and flattened in front,
+where the flexor tendons of the fingers are lodged. The extremities
+present characters which will be pointed out when the articulations of
+the fingers are studied.
+
+The articulations of each finger are: the metacarpo-phalangeal
+articulation, the articulation of the first with the second, and the
+articulation of the second with the third phalanges (inter-phalangeal
+articulations).
+
+Each _metacarpo-phalangeal articulation_ is formed by the globular
+head of the metacarpal bone being received into a glenoid cavity in the
+base of the first phalanx. Such an adaptation of articular surfaces
+will permit every kind of movement, and it is easy to understand
+that each finger can be bent on the metacarpus, straightened, and
+also inclined to either side (abduction and adduction--the act of
+separating and bringing together the fingers); but the articular
+capsule or fibrous band which surrounds each metacarpo-phalangeal
+joint fixes an exact limit to these movements. Flexion is a much
+more powerful movement than extension, because the capsules of the
+joints are deficient behind, their places being taken by a membranous
+expansion of the extensor tendons which passes over the backs of the
+joints. Thus extension cannot usually be prolonged further than that
+position in which the axis of the fingers forms a straight line with
+that of the metacarpal bones, for just then the anterior portion of the
+capsule is put on the stretch, and as this part is fibrous, thick, and
+resisting, it prevents any increase of extension. When the anterior
+ligament is thinner and more relaxed, as sometimes in the female hand,
+the fingers can be straightened beyond the straight line, and form
+an obtuse angle with the metacarpus. On the other hand, this capsule
+is strengthened on either side by a lateral ligament, which, being
+inserted at the posterior part of the head of the metacarpal bone, is
+put on the stretch when the act of flexion is produced, and when this
+act of flexion arrives at a right angle, the lateral ligaments do not
+permit it to be carried any farther. It is easy to prove this upon
+ourselves, as we cannot flex the first phalanx on the metacarpus beyond
+this point, and we cannot, in any case, bring the anterior surface of
+the first phalanx of a finger in contact with the palm of the hand, but
+only the second and third phalanges.
+
+_Inter-phalangeal Articulations._--The articulations of the
+phalanges--that is, those of the first with the second, and those of
+the second with the third--are constructed on a different plan from
+the metacarpo-phalangeal articulations. Instead of a head received
+into a glenoid cavity, we find here, at the inferior extremity of
+the first and second phalanges, a surface formed like a pulley, or
+trochlea, with two lateral lips separated by a groove or hollow
+(Fig. 29); and, on the other hand, on the superior extremity of the
+second and third we find two cavities corresponding to the lips of
+the pulley, separated by a median projection which corresponds to the
+groove. Therefore, given a single phalanx, it will be easy to say
+whether it is a first, second, or third phalanx, as the first phalanx
+has at its upper end a single articular cavity, while the second and
+third have two placed side by side; and again, the third, or ungual,
+phalanx may be distinguished at the first glance from the second by the
+shape of its free extremity, which is expanded in front into a rough
+surface shaped like an arrow-head for the support, not of the nail,
+but of the pulp of the finger. The inter-phalangeal joints reproduce
+on a smaller scale the pulley, or trochlea, and joint of the elbow,
+and present an analogous mechanism permitting only the movements of
+flexion and extension. In fact, as each of us may prove upon his
+own hand, while the fingers may be moved from side to side at their
+metacarpo-phalangeal articulations, the several phalanges can only be
+flexed and extended at the inter-phalangeal joints; in other words,
+while the finger enjoys great freedom of movement at its base, it only
+possesses that of flexion and extension in its component parts. Here
+again, and for the same reason, flexion is the more powerful movement.
+The movement of extension of the phalanges is limited, because the
+anterior portion of the articular capsule put on the stretch by the
+movement is stout and strong, but we find a great variety in different
+subjects, and with some, such mobility that the terminal phalanges can
+be bent backwards. Flexion is limited only by the contact of the soft
+parts on the anterior surface of a phalanx.
+
+_The Proportions of the Upper Limb._--Having examined the skeleton
+of the upper limb in relation to form and movement, it is necessary
+next to study its proportions--namely, to inquire, on the one hand,
+what comparison the length of the limb bears to the height, and, on the
+other, to compare the length of the different segments of the limb with
+each other.
+
+The comparison between the upper limbs and the height may be expressed
+in two ways: first, by examining the two arms outstretched in the
+horizontal position; the distance which then separates the extremity
+of one hand from that of the other is termed the _span of the upper
+limbs_, and this transverse measure includes not only the length of
+the arms, but also the breadth of the shoulders; secondly, by examining
+the upper limb hanging vertically beside the body, and noting to what
+level on the lower limb the extremity of the hand (nail of the middle
+finger) reaches.
+
+The relation of the span of the upper limbs to the height has been
+expressed long since by the formula known as the _square figure of the
+ancients_ (Fig. 30). If we draw two horizontal lines, one at the soles
+of the feet (_c_, _d_), the other at the summit of the head (_a_, _b_),
+and two vertical lines at right angles to the extremities of the two
+arms horizontally outstretched, these four lines form by their junction
+a perfect square; in other words, the man having the arms horizontal is
+enclosed within a square. This shows that the span of the arms is equal
+to the height.
+
+  [Illustration: FIG. 30.
+
+  Figure in a square, ancient method.]
+
+This statement is correct for a man of the Caucasian race of the middle
+height, but it is not so for the yellow and black races, in whom the
+span of the arm is greater than the height. If from man we pass on to
+the anthropoid apes (chimpanzee, gorilla, &c.), we find that the span
+of the arms in these becomes more and more extended as compared with
+the height. Thus, in the gorilla, the height being 5 ft. 7¼ in., the
+span becomes 8 ft. 9¼ in.; and in the chimpanzee, to a height of 5 ft.
+5¼ in. the corresponding span is 6 ft. 6 in.
+
+Again, when we examine the upper limbs hanging freely beside the body,
+we find that in the European of average height the extremity of the
+middle finger corresponds in general to the middle of the thigh; in
+subjects of short stature this extremity of the hand descends a little
+lower than the middle, and, on the other hand, in very tall men it
+ends at a higher level. In the yellow and black races the extremity
+of the hand descends much lower than the middle of the thigh; and in
+the anthropoid apes we find that, in the chimpanzee, the extremity of
+the hand descends below the knee; in the gorilla it corresponds to
+the middle of the leg; and, finally, in the orang-outang, and in the
+gibbon, it reaches almost to the ankle.
+
+If we seek among the various portions of the upper limb a part which
+would answer as a common measure between them, we cannot find anything
+satisfactory in this respect. The length of the hand, which would
+naturally seem to be indicated as a measure, is not contained an even
+number of times in the length of the bones of the shoulder, arm, or
+forearm. If, however, we take from the hand the length of the third
+phalanx of the middle finger, we have a measure equal to that of the
+vertebral border of the shoulder-blade, or of the clavicle. Under those
+conditions we may say that the length of the humerus is equal to twice
+that of the hand, and that of the forearm equal to one and a half the
+length of the hand; but these proportions are so variable that they
+cannot be insisted on. We should attach more importance to the rule
+that takes the hand as a common measure of the entire body in regard
+to height, taking the height as being equal to ten hands. This is a
+proportion which often answers in reality, but which presents too many
+exceptions to be laid down as a law.
+
+We may here state the fact once for all, that there is not an
+_absolute rule_ for the anatomist, or system of proportions
+applicable to every class of subject, to those of small as well as
+those of large stature. If, on the contrary, an ideal proportion is
+adopted, in which a human figure has been altered, so as to correspond
+to the abstract conception of beauty, we say that this question of
+proportion belongs no longer to the domain of anatomy or observation,
+but that here we rather touch æsthetic doctrines; it is for this reason
+that we have limited ourselves, when putting forward various ideas of
+proportion, to indicating, within such limits as direct observation
+permits, whether a part of a limb might serve as a common measure for
+this limb or for the total length of the body.
+
+  [Illustration: FIG. 31.
+
+  The Egyptian Canon.]
+
+The _Egyptian canon_ as demonstrated by Charles Blanc, which has a
+certain historical interest, is that the _length of the middle finger_,
+taken as a common measure, should be contained nineteen times in the
+length of the body. In fact, the “Selection of Funeral Monuments” by
+Lepsius (Leipzig, 1852) contains the drawing of a very curious Egyptian
+figure, divided by transverse lines into nineteen parts (not including
+the head-dress). Now as several passages in different ancient authors
+seem to indicate that the Egyptian sculptors have taken the finger as
+the unit of the system, Charles Blanc very ingeniously remarks this
+fact, that in the figure in question, one of the horizontal lines, the
+eighth beginning at the soles of the feet, passes exactly at the base
+of the middle finger in the right hand (closed holding a key), while
+the seventh touches the extremity of the middle finger of the extended
+left hand. It seems to him, then, very probable that the distribution
+of these horizontal lines indicates a system of measuring the figure,
+and that the space between the seventh and the eighth line measures the
+length of the middle finger, which thus becomes the standard of this
+system of proportion. According to the Egyptian rule, the length of
+the middle finger will be found nineteen times in that of the height
+(Fig. 31); it may be that this rule was adopted by the Greek artists,
+and Charles Blanc does not hesitate to think that Polycletus, who has
+composed a _Treatise on Proportions_, with a model in marble known
+by the name of _Doryphorus_, used no other system but the Egyptian;
+there has been always found in a number of antique figures this same
+proportion of nineteen times the middle finger to the height of the
+body, and in the Achilles, for example, the total height does not
+exceed by more than ¹⁄₂₀th of an inch the length of the middle finger
+multiplied by nineteen.
+
+_Brachial Index._--An interesting proportion to note is that between
+the arm and forearm, especially as it has been with anthropologists
+the subject of important researches, and will familiarise us with
+the term _index_, which we must frequently make use of, especially
+when comparing the transverse and antero-posterior diameters of the
+cranium. We give, in anthropology, the name _index_ to the number
+which expresses the proportion of one dimension to some other, this
+last being represented by 100. Supposing, in fact, that we compare one
+length, A, equal to one metre, with another length, B, equal to two
+metres, in this case, the first length being half that of the second,
+we speak of the index found as 50 (because 50 is the half of 100, and
+we suppose the second length to be equal to 100). Now the forearm is
+shorter than the arm; it represents about three-fourths of it; if,
+then, we take the number 100 to represent the length of the humerus,
+the number 75, which is three-fourths of 100, would represent the
+length of the forearm; and then in denoting by the _brachial index_
+the proportion of the length (always shorter) of the forearm with that
+of the arm (always longer) we simply say that the brachial index is
+represented by 75.
+
+This method of notation, which reduces any numerical proportion to the
+decimal system, is very valuable, as it permits us to follow without
+difficulty the degree in which a proportion varies according to the
+race or species.
+
+Thus we come to speak of the brachial index (proportion of the forearm
+to the arm) as 75. We have chosen this particular number in order to
+make the example easy; in reality, in adult European subjects this
+index is only 74--that is to say, that the forearm is to the arm as 74
+is to 100. If we measure the same parts in the adult negro, and reduce
+to the decimal proportion the numbers obtained, we find the brachial
+index here is 79--or that the forearm is to the arm as 79 to 100. In
+the negro, then, the forearm is longer compared with the arm, as 79
+is a greater part of 100 than 74. Finally, if we pass on from the
+human species to the anthropoid apes, we see that the brachial index
+comes to be 80, and even 100--that is to say, that the length of the
+forearm becomes equal to that of the arm; and we know, therefore, that
+the great length of the upper limbs in the anthropoids (page 86) is
+principally owing to the greater length of the forearm. But the most
+interesting fact is that in the human race the brachial index is not
+the same at different ages--thus, in the European infant at birth this
+index is 80; before the end of the first year it is only 77, and by
+degrees during childhood it descends until it arrives at 74 in the
+adult. This clearly shows that the humerus, during the growth of the
+body, lengthens in proportion more than the bones of the forearm;
+so that they, which were at first to the humerus as 80 is to 100,
+come gradually to be as 77 to 100, and finally as 75 or 74 to 100.
+If we were to glance at comparative osteology we should see that, in
+such animals as the lion or the horse, the forearm becomes longer in
+proportion to the humerus, so as to equal, and afterwards to surpass,
+the length of that bone.
+
+
+
+
+                              CHAPTER IX.
+
+                              THE PELVIS.
+
+   The bony structure of the hips.--The pelvis; _sacrum_ (five
+   vertebræ welded together); _coccyx_ (the caudal appendage in man
+   and the monkeys resembling man); the _innominate bones_ (ilium,
+   pubis, ischium); the cotyloid cavity; the acetabulum and its
+   notch.--The articulations of the pelvis, sacro-iliac and pubic;
+   sacro-iliac ligaments; ilio-pubic, or Poupart’s ligament (fold
+   of the groin); ligaments of the hip-bones.--The pelvis as a
+   whole.--Comparison of the pelvis in the male and female.
+
+
+The pelvis is formed by the union of the two hip-bones, one on either
+side, with the vertebral column, so as to form the pelvic cavity or
+basin, which is bounded behind by the lower portion of the vertebral
+column, sacrum and coccyx, laterally by the hip-bones, and in front
+by the _symphysis pubis_, the antero-inferior articulation of the
+two hip-bones together. It completes the trunk and abdomen in their
+lower parts, and serves to articulate with the thigh-bones (femora)
+externally. There is a great contrast between the shoulder girdle and
+the pelvic girdle. The former is freely movable, and has only a slight
+attachment by the sterno-clavicular joint to the axial skeleton: the
+latter is immobile, and is firmly adherent to the vertebral column
+(sacrum) by means of the sacro-iliac joint and powerful accessory
+ligaments.
+
+The _os sacrum_ (Figs. 5, 8, 32, 35, 38), so called because it was
+the part of the trunk offered in sacrifice by the ancients to their
+gods, is formed of five vertebræ (sacral vertebræ) fused together
+by osseous union, the separate portions of which are easily seen on
+careful examination. Taken as a whole it forms a pyramid, the base
+of which (2, Fig. 35) is turned upwards and forwards, corresponding
+to the body of the first sacral vertebra. This sacral pyramid, being
+directed obliquely from above downwards and backwards (Figs. 8, 9),
+presents a surface called antero-inferior, or rather inferior, on
+which we recognise five united vertebral bodies (Fig. 5, page 28); a
+postero-superior surface--better called superior--on which we recognise
+the rudimentary spinous processes (Fig. 9, page 38) and the laminæ of
+these same five vertebræ, these portions being all united together;
+and, finally, the lateral surfaces, expanded above to form the
+_auricular surface_ for articulation with a similar surface on the
+hip-bone. This surface extends over the sides of the first three sacral
+vertebræ; and behind it are rough excavations for the attachment of the
+powerful posterior sacro-iliac ligaments.
+
+  [Illustration: FIG. 32.
+
+  SECTION OF THE PELVIS.]
+
+The _coccyx_ (21, Fig. 5), placed below the sacrum, is a rudimentary
+caudal appendage, but instead of being, as in the greater number
+of mammals, free and movable, it is found in man curved towards the
+interior of the pelvis, whose inferior outlet it contributes to close.
+Its borders give attachment to powerful _sacro-sciatic ligaments_,
+which help to fill up the space between the vertebral column and the
+hip-bone on each side.
+
+  [Illustration: FIG. 33.
+
+   THE HIP-BONE OF AN INFANT: its three primitive pieces:--1,
+   ilium;--2, its superior border;--5, 6, ischium, its acetabular
+   part (in 7);--8, pubis, its acetabular part (11).]
+
+The coccyx is formed of a series of four vertebræ, welded one with the
+other, and so diminished in size that each of them is reduced to a
+small osseous nodule, representing a rudimentary vertebral body.
+
+The _hip-bones_ (_ossa innominata_) are two in number, one on each
+side, articulating behind with the sacrum, and uniting with each other
+in front (Figs. 35, 38) to form the symphysis pubis. In order to
+understand the arrangement of the parts of which a hip-bone consists
+it is necessary to notice that this bone is made up originally, in an
+infant, of three distinct parts, which are afterwards joined together
+as age advances; of these parts, the superior is called the _ilium_;
+the two others are inferior; that placed in front is called the
+_pubis_, and that behind, the _ischium_ (Fig. 33). The junction of the
+three parts is effected at the central portion of the bone, at the
+bottom of the great articular cavity of the hip-joint (acetabulum).
+The names of almost every part of the hip-bone are derived from its
+three constituent portions--namely, the _ilium_, _pubis_, and _ischium_.
+
+  [Illustration: FIG. 34.
+
+   RIGHT HIP-BONE (external surface).--1, 1, iliac crest;--2,
+   anterior superior iliac spine;--3, posterior superior iliac
+   spine;--4, superior curved line;--5, inferior curved line;--7,
+   anterior inferior iliac spine;--11, ischial spine;--12, great
+   sciatic notch;--13, acetabulum; and 14, its pit (fovea);--16,
+   its great notch, directed downwards;--17, spine of pubis;--18,
+   horizontal ramus of pubis;--19, body and descending ramus of
+   pubis;--20, 20, tuberosity of ischium;--22, obturator foramen.]
+
+  [Illustration: FIG. 35.
+
+   PELVIS OF THE MALE.--1, 1, iliac crests;--2, sacrum;--3,
+   symphysis pubis;--5, 5, acetabula;--6, 6, rami of pubes and
+   ischia;--7, 7, obturator foramina;--10, 10, iliac fossa.]
+
+Examining first the external surface of the bone, we notice that its
+upper part is expanded into a large area called the _dorsum ilii_
+(5, Fig. 34), which is crossed by three curved lines limiting the
+attachments of the gluteal muscles (4 and 5, Fig. 34). Below this area
+the bone is narrowed and presents a circular cavity (13 and 14, Fig.
+34), broad and deep, which has received the name of the _acetabulum_ (a
+vinegar-cup); its use is to form the articular socket of the hip-joint
+for the reception of the head of the femur. The margin of this cavity
+is prominent throughout its entire extent, except below, where it is
+deficient, and gives rise to the _notch_ of the acetabulum; this notch
+is a valuable starting-point to settle the natural position either of
+the iliac bone or of the entire pelvis (Fig. 34). If, in fact, this
+bone of the pelvis is supposed to belong to a figure in the upright
+position, the acetabular notch should be directed downwards, as shown
+in Fig. 34. Below the acetabulum the innominate bone is pierced by a
+large hole, called the _obturator_ or _thyroid foramen_ (22, Fig. 34),
+bounded by the following parts: behind, by the _ischium_ (20, Fig. 34);
+in front and above, by the _horizontal ramus of the pubis_ (18); below,
+by a bony plate formed by a prolongation of the pubis (19) proceeding
+to join a corresponding prolongation of the ischium. These united
+bars of bone are called the _descending ramus of the pubis_ and the
+_ascending ramus of the ischium_, and they unite to form with those
+of the opposite side the _pubic arch_ of the completed pelvis. The
+internal surface of the innominate bone is divided into upper and lower
+parts by a diagonal line--the _ilio-pectineal line_--which separates
+the iliac portion of the bone from the part formed by the ischium and
+pubis, and also serves to separate in the complete pelvis the upper
+abdominal part (_false pelvis_) from the cavity of the true pelvis
+below. Above this line is the internal expanded surface of the ilium
+known as the _iliac fossa_ (10, Fig. 35). At its posterior end is the
+_auricular surface_ of the ilium, for articulation with the sacrum.
+Below it are, first, a flat surface corresponding to the floor of the
+acetabulum, and, lower still, the obturator foramen, bounded as we
+have already described. The borders of the hip-bone are distinguished
+(Fig. 34) as superior, anterior, posterior, and inferior. The _superior
+border_, called the _crest of the ilium_ (1, Fig. 34), is thick and
+curved like an italic ∫; it is this which marks on the living model the
+outline of the hip--namely, the limit between the lateral part of the
+abdomen and the lateral part of the pelvis. It ends in front in the
+_anterior superior spine_ (2, Fig. 34), and behind in the _posterior
+superior spine_ of the ilium. The anterior border begins at the
+anterior superior iliac spine, and presents in succession, from above
+downwards, a notch, then a prominence called the _anterior inferior
+spine of the ilium_ (7, Fig. 34), below which is a groove giving
+passage to the psoas muscle (see later) bounded on its inner side by
+the _ilio-pectineal eminence_; finally, this border is continuous
+with the _horizontal ramus of the pubis_, and ends internally in the
+_spine_ and _crest of the pubis_ (17, Fig. 34). The posterior border of
+the bone is similarly marked by projections and notches. It is limited
+above by the _posterior superior spine of the ilium_ (3, Fig. 34),
+and below by the _tuberosity of the ischium_; and between these are
+two smaller projections--the _posterior inferior spine of the ilium_
+above, and the _spine of the ischium_ below. The ischial spine serves
+to divide the border into two unequal notches, of which the superior,
+the larger, is called the _great sciatic notch_ (12, Fig. 34), and
+the inferior, the smaller, the _lesser_ sciatic notch. Finally, the
+_inferior border_ is formed by the rami of the pubis and ischium. We
+will finish the description of this bone by describing its four angles:
+the antero-superior (2, Fig. 34) is formed by the anterior superior
+iliac spine; the antero-inferior (17, Fig. 34) by the body of the
+pubis, which here presents a rough oval surface of considerable extent
+which articulates with the pubis of the opposite side to form the
+_symphysis pubis_; the postero-inferior angle (20, Fig. 34) is formed
+by the tuberosity of the ischium; and finally, the supero-posterior,
+thick and flattened, presents on its outer side the posterior iliac
+spines, and on its inner side the large rough _auricular surface_, for
+articulation with the sacrum.
+
+In order to construct the pelvis, the two hip-bones are joined together
+(at the _symphysis pubis_), and also join the sacrum (sacro-iliac
+synarthrosis) by articulations which have nothing in common with those
+which we have already studied in the limbs--for example, the shoulder
+or elbow. In those articulations of the limbs the bones were in contact
+by smooth surfaces, which glided one upon the other without anything
+interposed between them; such articulations are characterised by their
+mobility. On the other hand, the sacrum is united on each side to the
+hip-bones, and the hip-bones themselves articulate in front with each
+other by rough surfaces, between which are placed plates, more or
+less thick, of fibro-cartilage (similar to the intervertebral discs),
+which, in consequence, do not allow them to glide one on the other,
+but closely join them together. These articulations, which bear the
+name of _synarthroses_, or _symphyses_ (_σύν_, together; _φύομαι_, to
+weld), are remarkable not for mobility, but for rigidity. They are
+characterised by the possession, between the articulating bones, of
+plates of fibro-cartilage, which act as tough but elastic buffers.
+Behind, the two _sacro-iliac synarthroses_ support the sacrum, which is
+firmly wedged in between the two bones of the hip, and is slung between
+them, while the strong ligaments placed above the joint permit the
+sacrum to support the weight transmitted to it by the vertebral column.
+In front and below, the _symphysis pubis_ (3, Fig. 35), besides having
+fibro-cartilage placed between the bones and adherent to them, is also
+strengthened by fibrous bands passing superficially from one bone to
+the other.
+
+These articulations weld the component parts of the pelvis (the sacrum,
+with the two hip-bones) into a complete basin; but, at the same time,
+owing to the elasticity of these joints, the pelvis can resist without
+injury the shocks which are transmitted to it by the vertebral column
+and the lower limbs. The sacro-iliac and pubic fibro-cartilages break
+and check the shock which is produced--when, for example, we jump from
+a height and alight on the soles of the feet.
+
+Besides the sacro-iliac joint and the articulation of the symphysis
+pubis, the pelvis also possesses other ligaments accessory or
+special to the hip-bone. The accessory ligaments are those which
+strengthen the sacro-iliac joint. Above the articulation are the
+_ilio-lumbar_ ligament, passing from the transverse process of the
+last lumbar vertebra to the iliac crest at its posterior end, and
+the _sacro-vertebral_ ligament, passing from the same transverse
+process to the lateral mass of the sacrum. Below the joint are the
+two _sacro-sciatic ligaments_, which, arising together from the side
+of the sacrum and coccyx in the form of a broad fibrous band, proceed
+outwards, and, diverging, are attached, one--the _great sacro-sciatic
+ligament_--to the tuberosity of the ischium, the other--the _lesser
+sacro-sciatic ligament_--to the spine of the ischium. These ligaments
+convert the sacro-sciatic notches into foramina, through which
+important muscles pass; and, but for this fact, these ligaments would
+not need mention here, as they do not appear superficially, being
+covered by the mass of the gluteal muscles. The _special ligaments_
+of the hip-bone are the _triangular ligament_, which is a membrane
+partly filling up the pubic arch; the _obturator membrane_, which
+almost completely fills the obturator foramen; and _Poupart’s ligament_
+(really derived from the aponeurosis of the external oblique muscle
+of the abdomen, which stretches between the anterior superior spine of
+the ilium and the spine of the pubis). It is immediately subcutaneous,
+and corresponds to the fold of the groin. The subcutaneous fascia
+is attached to the entire length of the ligament, and so creates a
+depression extending from the spine of the ilium to the pubis. This
+fold of the groin marks the limit between the skin of the abdomen
+and that of the thigh. As the deep fascial envelope of the thigh is
+attached to Poupart’s ligament in its whole length, it pulls on the
+ligament so as to make it convex downwards in the extended position of
+the lower limb.
+
+The whole pelvis is expanded above and narrower below, and the lower
+part of it is, for the most part, concealed from view in the living
+model. The lower limbs are attached on each side in such a manner that
+they approach each other at the lower part of the pelvis, so as to
+leave between them only a narrow interval--the _perineum_, which
+corresponds to the genital organs and the parts between the folds of
+the buttocks. But the upper outline of the pelvis is clearly marked
+throughout the whole of its extent: on each side the iliac crests,
+on the superior borders of the hip-bones, form a slightly undulating
+line, the middle portion of which is most elevated, while its anterior
+extremity inclines abruptly downwards to terminate at the anterior
+superior spine of the crest of the ilium, clearly seen in the model
+when the skin is not loaded with fat; in front, the pelvis presents an
+extensive curved outline with its concavity upwards, the central parts
+corresponding to the symphysis pubis, and the lateral parts formed by
+Poupart’s ligament on each side. This anterior outline of the pelvis
+forms the lower limit of the abdominal wall. This helps to give the
+anterior abdominal wall the form of a shield rounded at both upper
+and lower ends, a form which the ancients seem to have exaggerated
+in adopting for the epigastric pit a configuration rounded instead
+of oval, which is the shape it presents in the skeleton. We have
+previously (page 54) shown how, in numerous cases, the form adopted by
+the ancient sculptors is sufficiently justifiable.
+
+  [Illustration:
+
+    FIG. 36.      FIG. 37.
+
+   Diagrams showing that the pelvis of the male (A) represents a
+   long segment (_a, b, c, d_) of a short cone (_a, b, x_), while
+   the pelvis of the female (B) represents a short segment (_a, b,
+   c, d_) of a long cone (_a, b, x_).]
+
+After having studied the pelvis with regard to its mechanism and its
+influence on external form, we ought now to examine it with regard
+to its proportions--namely, its transverse dimensions; but as the
+prominence of the hips is formed not only by the superior border of
+the iliac bones, but also by the great trochanters of the femur, this
+examination cannot be completed without reference to the relation of
+the bones of the thigh to the pelvis. For the moment, therefore, we
+must confine ourselves to the study of the proportions of the pelvis in
+the male and in the female skeleton.
+
+  [Illustration: FIG. 38.
+
+  Pelvis of the female.]
+
+Generally speaking, the pelvis of the female is broader and shorter
+than that of the male; in the male (Fig. 35) the superior transverse
+diameter, which is a line that passes through the most prominent
+portion of the crest of the ilium of one side to the corresponding part
+of the other, measures from 10 to 12 inches (on the average 11 inches);
+whilst in the female this line measures from 10¼ to 13¾ inches (on the
+average 12 inches). On the contrary, the height of the pelvis in man
+is about 8 inches, whilst it is not more than 7¼ inches in the female.
+Again, comparing (Figs. 35 and 38) a male with a female pelvis, we see
+that the first is narrow, the second comparatively broad between the
+ischial tuberosities.
+
+If we suppose a line drawn at a tangent to the sides of the pelvis, we
+see that these lines must be prolonged downwards for a considerable
+distance in order to meet in the female pelvis, but that in the male
+pelvis they join at a shorter distance from the pelvic outlet. In
+order to reduce these facts to a simple formula we may say, therefore,
+that the _pelvis of a male represents a long segment of a short cone_,
+while _that of the female represents a short segment of a long cone_.
+The student is referred to Figs. 36 and 37, which show this arrangement
+by means of a simple diagram.
+
+The particular details of shape which distinguish the pelvis in the two
+sexes are the following:--_The thickness of the walls_: in the male
+the bones of the pelvis are stronger, the iliac crests are thicker,
+more curved, and less expanded, and the different prominences for the
+insertions of muscles are better marked. The _pubic arch_, limited
+above by the symphysis, and on each side by the descending rami of the
+pubis, is very broad, and has everted edges in the female, in whom it
+assumes the form of an elliptical arch, while in the male (compare Fig.
+35 and Fig. 38 at 3, 6, 6) this same arch is narrow and raised, and
+takes the form of a pointed arch. For the same reason the _tuberosities
+of the ischium_ are wider apart in the female than in the male. The
+_spine of the ischium_ in the female is turned backwards, and appears
+less obviously in the pelvic cavity. The _obturator foramina_ are wide
+and triangular in the female, while they are narrow and oval in the
+pelvis of the male. The _sacrum_ is relatively shorter and broader in
+the female than in the male.
+
+
+
+
+                              CHAPTER X.
+
+                   THE THIGH, FEMUR, AND HIP-JOINT.
+
+   The femur: its superior extremity: _neck_, _head_, and
+   _trochanters_.--Hip-joint, or _coxo-femoral articulation_;
+   movements of the joint; limits of these movements; limits
+   of extension (ilio-femoral ligament); adduction (ligamentum
+   teres); the influence of atmospheric pressure (experiments of
+   the brothers Weber).--The transverse dimensions of the hips and
+   shoulder in the male and female; the various formulæ (ovoid of
+   the ancients, ovoid and elliptical of Salvage); the correct
+   formula; the inter-humeral and inter-trochanteric diameters; the
+   inter-acromial and inter-iliac diameters.--The external form of
+   the region of the hips and great trochanter in particular; the
+   osseous prominences brought into relief on the surface as flat
+   and depressed surfaces.
+
+
+The femur (Figs. 39 and 43), or bone of the thigh, is one of the long
+bones. It is the largest bone in the skeleton, and consists, like all
+the long bones, of a shaft and two extremities (Fig. 39). In this
+chapter we have to consider its upper end, and its articulation with
+the hip-bone.
+
+  [Illustration: FIG. 39.
+
+   VERTICAL SECTION OF FEMUR.--1, 1, 2, 2, the body of the bone
+   with the medullary canal hollowed out;--3, the great trochanter,
+   whence the neck is given off, terminating in the head;--4,
+   inferior extremity of the bone.]
+
+The upper extremity of the femur is composed of a _head_, a _neck_,
+and of two tuberosities (the _great_ and _small trochanters_) placed
+at the junction of the neck with the body of the bone. The head of the
+femur (5, Fig. 43) is regularly rounded, and forms three-fourths of a
+sphere. Its spherical surface, turned inwards, upwards, and forwards,
+is smooth and covered with cartilage, except at a pit (6, Fig. 43) seen
+a little below and behind its centre, which gives attachment to the
+_ligamentum teres_--a strong fibrous band which connects the femur to
+the acetabulum.
+
+The neck of the femur (7, Fig. 43), connecting the head with the
+shaft, is directed downwards and outwards in the form of a cylinder,
+flattened a little from front to back, to become attached to the
+upper extremity of the shaft of the femur at an obtuse angle, looking
+downwards and inwards (Fig. 39). This angle which the axis of the neck
+makes with that of the body varies in different individuals. In the
+adult male it is about 135 degrees; in the female it is less open--that
+is, it approaches nearer to a right angle. This helps to increase the
+transverse diameter of the hips in the female. Again, in both sexes
+this angle approaches gradually to a right angle with the advance of
+age--a change that assists in shortening the total height in the aged.
+At the junction of the neck of the femur with the body of the bone are
+the two tuberosities, or trochanters--one situated above and to the
+outer side, called the _great trochanter_ (3, Fig. 39; and 8, Fig.
+43); the other situated below and to the inner side, at the junction
+of the neck and the shaft, called the _lesser trochanter_ (10, Fig.
+43). The great trochanter is of large size, is quadrilateral in shape,
+and projects beyond the upper border of the neck. It presents on its
+surfaces and borders numerous impressions, for the insertion of the
+muscles of the buttock. The lesser trochanter, on the contrary, is
+smaller in size, mammillated or conical in shape, and gives attachment
+to the psoas and iliacus muscles only.
+
+_The Hip-joint._--The _ilio-femoral_ or _coxo-femoral_ articulation is
+formed by the reception of the head of the femur into the cavity of
+the acetabulum, in which it exactly fits. The edge of the cavity is
+surrounded by the _cotyloid_ and _transverse ligaments_, which clasp
+the head of the femur and serve to deepen the cavity and narrow its
+orifice. The articulation is a ball and socket joint (enarthrosis).
+As we should expect from the form of the articular surfaces, every
+possible description of movement can take place: the head of the femur
+can glide in all directions in the cavity in which it is received,
+producing the movement of _abduction_ (the inferior limb being carried
+outwards, away from the middle line), _adduction_ (towards the middle
+line), _flexion_ (forwards, the anterior surface of the thigh being
+brought towards that of the abdomen), _extension_ (backwards), and
+rotation, of the femur, outwards and inwards. But these movements are
+variously influenced by the disposition of the ligaments of the joint.
+Some are limited, others are very extensive.
+
+The ligamentous apparatus of the hip-joint consists of a thick capsule
+of fibrous tissue, which arises from the margin of the cotyloid cavity
+and encloses the head and neck of the femur. The disposition of this
+capsule is very different in front and behind.
+
+The capsule is composed of superficial longitudinal fibres stretching
+from acetabulum to femur, and thickened, except posteriorly, to
+form strong ligaments; and deeper, circular fibres, which _alone_
+constitute the back part of the capsule--consequently the capsule
+is thinner and weaker at the back, where the circular fibres appear
+superficially--constituting the _zona circularis_, or _ligament of
+Bertini_. The posterior portion of the capsule consequently cannot
+at any time become tense. The movement of flexion, indeed, may be
+continued as far as possible without causing tension of the back of
+the capsule of the joint. It is for this reason we speak of flexion of
+the thigh as unlimited, and, in fact, it may be continued until the
+anterior surface of the thigh comes in contact with the abdomen.
+
+The other movements of the thigh at the hip-joint are limited by the
+several longitudinal ligamentous bands of the capsule. In front, the
+capsule of the joint is put on the stretch when the thigh is carried
+backwards during extension, and the movement is checked when it arrives
+at a certain point. This is due to the _ilio-femoral_, or _Y-shaped
+ligament of Bigelow_, which extends from the acetabular margin to
+the front of the neck of the femur, dividing as it descends into two
+bands. It is the most important ligament of the hip-joint. Owing to the
+strength of this ligament, the movement of extension can be limited and
+checked at any given moment. Now if we try the experiment on ourselves,
+having flexed the thigh on the abdomen and then gradually extend it,
+we shall perceive that the movement is arrested at the moment when the
+axis of the thigh is in a continuous line with that of the body (or if
+the subject is upright, when the thigh is vertical). If we repeat this
+experiment on the dissected subject, with the joint prepared, we see
+that the ilio-femoral ligament is relaxed when the thigh is flexed on
+the pelvis, and becomes tense in proportion as the bone is extended,
+and that this tension arrives at its maximum when the femur is found
+in a line with the trunk, and the ilio-femoral ligament presents an
+insurmountable obstacle to any further extension.
+
+It is true that a man in the upright position can move his thigh
+backward; but it is necessary to observe, if, for example, it is the
+right thigh which is carried backward, it is not in the right hip-joint
+that the movement takes place, but in the left; in other words, the
+trunk is flexed upon the left femur. We may therefore state that when
+the thigh is so extended as to be in the same continuous plane with the
+trunk, the thigh and trunk form one and the same piece, and the two
+parts are incapable of further extension; and, consequently, when one
+thigh is carried behind the vertical line, the trunk must be rotated to
+an equal extent on the opposite side.
+
+The ilio-femoral band plays also an important part in the maintenance
+of the erect attitude. Being stretched in extension of the thigh, the
+head and neck of the femur rest against it, and so the erect position
+can be maintained without excessive muscular exertion. The ilio-femoral
+ligament also, aided by the _pubo-femoral_ band of the capsule,
+presents an obstacle to _abduction_, or the movement of the thigh
+outwards, in the upright position, when the ligament is tense. When the
+thigh is slightly flexed on the pelvis, and the ligament is relaxed
+abduction of the thigh becomes comparatively easy (Fig. 40).
+
+  [Illustration: FIG. 40.
+
+  OUTLINE OF BUTTOCK AND THIGH.]
+
+The movement of _adduction_, or bringing of the thighs together, is
+limited by the _ilio-trochanteric_ band of the capsule, and by the
+_ligamentum teres_--a special ligament, not part of the capsule,
+contained within the joint. This movement becomes very easy if the
+joint is slightly bent. If we try the experiment on an articulation
+in which the ilio-femoral ligament is cut, we perceive that in the
+position of extension the movement of adduction is just as difficult
+as if the ligament were intact. This is due to the presence of the
+_ligamentum teres_. This ligament is attached by one extremity to
+the rough depression below and behind the head of the femur, and
+by the other extremity, which is bifurcated, to the margins of the
+acetabular notch. We have already seen that in the pelvis of a man in
+the upright position this notch looks directly downwards (page 106);
+the ligament in this position is also vertical, and is put on the
+stretch, as the two ligaments, so to speak, help to suspend the pelvis
+on the heads of the femora. Now, in the upright position, the femur
+being vertical, the movement of adduction could be produced only by a
+gliding movement of the head of the femur in the acetabular cavity;
+but this gliding movement cannot take place, as the head of the femur
+is kept in position by the tense, round, or suspensory ligament. If,
+on the contrary, the femur is slightly flexed, the round ligament will
+be found relaxed; this permits the gliding of the head in the cavity,
+and at the same time permits of adduction, a movement which may now
+be accomplished with ease. An experiment which proves these facts
+without giving an anatomical demonstration of them (obtainable only
+from a prepared subject) is very easy to accomplish upon oneself. If
+one stands perfectly upright, rigid, with the body thrown backwards as
+far as possible, it will be seen that it is almost impossible to bring
+the two thighs and knees close together. Adduction is almost entirely
+lost in this position, so that we should be unable to bring the knees
+together and crush a fragile body, such as an egg, placed between them.
+But if, on the other hand, we flex the thighs a little, or the trunk is
+bent on the thighs, adduction becomes extremely easy, and now we can
+knock the knees together without any difficulty.
+
+The hip-joint is remarkable for the fact that upon it we can most
+conveniently demonstrate a law which applies also to all the other
+articulations, but of which we have reserved the explanation until
+now--namely, the law relative to _the influence of atmospheric pressure
+in maintaining articular surfaces in contact_. Up to the present, in
+studying the articulations, we have spoken of the form of the articular
+surfaces, and from their outline we have been able to deduce the
+nature of the movements permitted in the joint; we have spoken of the
+ligaments which surround the joint, and from their arrangement we have
+been able to infer the limits imposed upon these movements. But we have
+not spoken of the conditions which enable one articular surface to
+glide upon another without separating, and which maintain the surfaces
+in intimate and permanent apposition. It might be thought that this
+function devolves on the ligaments, but this would be an error; it is
+_atmospheric pressure_ which keeps up this contact.
+
+The head of the femur is fitted very exactly into the hollow of the
+acetabulum. In the first place, the head of the femur is in close
+contact with the cavity, the non-articular portion of which is filled
+up by adipose tissue. In the second place, the cotyloid ligament
+closely encircles the base of the head of the femur, and may be
+compared to the edges of a cupping-glass. Now, as a vacuum exists
+between the two articular surfaces, and the air cannot penetrate
+between them, they adhere very closely to each other, merely allowing
+one to glide on the other; but if by any means air is allowed to obtain
+access to the interior of the joint the bones naturally fall apart. The
+experiments which explain those facts were first demonstrated by the
+brothers Weber.
+
+We have felt it important to dwell here, once for all, on the important
+part which atmospheric pressure plays in the mechanism of joints.
+Analogous experiments show that this pressure plays comparatively
+the same part in other articulations in maintaining their articular
+surfaces in contact.
+
+MEASUREMENTS AND PROPORTIONS OF THE HIPS.--To return to the study of
+the region of the hips, we must now examine the _transverse dimensions_
+of this region, and the _external forms_ which result from the presence
+of bony prominences, especially the great trochanter of the femur.
+
+The _transverse distance_ which separates the one great trochanter of
+the femur from the other should be compared with the distance between
+the heads of the humeri; in other words, we must compare the _diameter
+of the hips_ with that of the _shoulders_.
+
+What strikes us most in this comparison, at the first glance at a
+series of skeletons, is the great projection which the hips form in
+the female. In order to express this difference, various formulæ have
+been proposed. In one such formula the trunk is regarded as a figure
+more or less regularly oval, of which one extremity corresponds to the
+shoulders, the other to the hips, and in the two sexes the diameter
+is greater at one end than at the other. The ancients expressed the
+formula in the following manner:--In the male and in the female the
+trunk represents an ovoid--that is to say, an oval similar to that of a
+figure of an egg having a greater and a smaller extremity. In the male
+this figure has its greater end above, while in the female the lower is
+the larger end. According to this formula, in the female the diameter
+of the hips exceeds that of the shoulders, while in the male it is the
+diameter of the shoulders which exceeds that of the hips. The formula,
+as regards the female at any rate, is evidently exaggerated. In fact,
+Salvage and Malgaigne proposed the following formula:--Allowing that
+the trunk of the male is an ovoid, with the greater extremity superior,
+the trunk of the female forms an ellipse--that is to say, a figure in
+which both extremities are of the same dimensions; so that while in the
+male the diameter of the shoulders exceeds that of the hips, in the
+female the diameter of the hips is just equal to it.
+
+Now this last formula also exaggerates the real proportions of the
+hips in the female. The correct formula is as follows:--In the
+male, as well as in the female, the trunk represents an ovoid with
+the greater diameter above; but while in the male the difference
+between the greater extremity and the smaller is very considerable,
+in the female this difference is very slight. We can see by actual
+measurements that in the female the diameter of the hips, though always
+less, differs very little from that of the shoulders. In the male,
+the distance from the head of one humerus to the corresponding part
+on the opposite side (_inter-humeral diameter_) is on the average 15¼
+inches, and the measure taken from one great trochanter to the other
+(_inter-trochanteric diameter_) is 12¼ inches; a difference between
+the two diameters of about one-fifth. In the female, the inter-humeral
+diameter is on the average 13¾ inches; the inter-trochanteric
+diameter is 12½ inches; therefore there is between the two diameters
+a difference of about one-twelfth. These figures also serve to
+demonstrate that the diameter of the shoulders is greater in the male
+than in the female (15 to 14), and that inversely the diameter of the
+hips is greater in the female than in the male (12½ to 12¼); so that,
+accordingly, if a man and a woman of average stature are supposed to
+throw their shadow on the same portion of a screen, the shadow of the
+shoulders of the male would cover a much larger surface than the shadow
+of the shoulders of the female; and, on the contrary, the shadow of the
+hips of the woman would exceed the shadow of the hips of the man, but
+only to a very small extent.
+
+In the foregoing paragraphs we have dealt with the transverse
+hip-measurements as inter-trochanteric. There is, however, another
+method of measurement, which justifies to a certain extent the formulæ
+adopted by the authors previously mentioned; it consists in comparing
+on the skeleton in both sexes the diameter of the pelvis without the
+femora with the diameter of the shoulders without the humeri. In this
+instance the shoulders are represented by the _inter-acromial_, and
+the hips by the _inter-iliac diameter_ (from one iliac crest to the
+other). Under these circumstances the exact measurements show that in
+the male the inter-acromial diameter is 12¾ inches, and the inter-iliac
+11 inches; therefore, as in the other formula, the trunk, deprived of
+its members, still represents an ovoid, with its greater extremity
+superior. On the other hand, in the female, the inter-acromial diameter
+is 11½ inches, and the inter-iliac measurement is 12 inches; so that
+here the trunk, deprived of its members, represents an ellipse or an
+ovoid, with its greater extremity below, although the upper extremity
+differs very little in size from the lower. The fault of this method of
+measurement is that it does not explain things as they are. The artist
+does not contemplate the torso as otherwise than complete--that is to
+say, provided with the upper and lower limbs--and it is absolutely
+necessary to take into account the part which the head of the humerus
+and the great trochanter of the femur take in the formation of the
+contours of the shoulder and hips. We have thought it desirable,
+however, to demonstrate this mode of measurement, because of the clear
+illustration which it gives of the greater diameter of the female
+pelvis as compared with that of the male.
+
+If we arrange in a table the figures given above for the inter-humeral,
+inter-trochanteric, inter-acromial, and inter-iliac diameters in the
+male and in the female, or if, better still, we represent those figures
+by lines intended to express, on the profile of a man and that of a
+woman, the proportionate value of the diameters of the region of the
+shoulders compared with the diameters of the pelvis and the hips, we
+obtain two figures which express in a striking manner all that has been
+pointed out (Figs. 41 and 42).
+
+  [Illustration: FIG. 41.
+
+   Diagram comparing the diameters of the hips with the diameters
+   of the shoulders in the male.]
+
+  [Illustration: FIG. 42.
+
+   Diagram comparing the diameters of the hips with the diameters
+   of the shoulders in the female.]
+
+We see, in fact, that in the male subject (Fig. 41) the vertical
+lines (_y_ and _y_) passing through the extremities of the
+inter-trochanteric (_d d_) and the inter-iliac (_c c_) diameters,
+both fall within the extremity of the inter-humeral (_b b_), and also
+the inter-acromial diameter (_a a_); on the contrary, in the female
+(Fig. 42) we find that these same vertical lines both fall within the
+extremities of the inter-humeral (_b b_), but on the outer side of the
+inter-acromial (_a a_) diameter.
+
+_The Great Trochanter._--A word is necessary concerning the influence
+of the great trochanter of the femur on the external form of the hip.
+Looking at the skeleton the great trochanter is seen to stand out so
+clearly and forms a projection so considerable that we should expect
+to see on the model a prominence corresponding to its shape. This,
+however, is not so. The gluteal muscles which proceed from the pelvis
+to be attached to the great trochanter are numerous and thick, and
+the fleshy bellies of the more superficial form a projection which is
+raised above the trochanter; while over the process they are replaced
+by tendons, more or less flattened, so that the trochanter is marked on
+the surface by a depression bounded by the muscles--the tensor vaginæ
+femoris in front, the glutei muscles above and behind. Below, the
+concave space corresponding to the great trochanter is continuous with
+the broad, flat surface which occupies the outer aspect of the thigh.
+
+There are many analogous cases where osseous projections are frequently
+marked on the external figure by a depression, and the reason is
+always the same as that just explained, that these osseous projections
+give insertion to muscles, the fleshy bellies of which give place to
+tendinous expansions at a little distance from them, and form by their
+thickness a raised surface round the prominence; in a general way,
+then, we may say that, with a few exceptions (such as the malleoli of
+the ankle-joints), wherever an osseous surface is covered over only
+by the skin, the muscles which surround this surface arise above its
+level, and in consequence the bone is marked by a depression, more or
+less pronounced as the subject is more or less muscular. Similarly, the
+middle portion of the sternum is marked superficially by a depression
+limited on each side by the swelling of the great pectoral muscles, and
+the internal surface of the tibia forms a long and broad groove when
+the anterior and posterior muscles of the leg are well developed.
+
+
+
+
+                              CHAPTER XI.
+
+                          THE THIGH AND KNEE.
+
+   The bony structure of the thigh and knee.--Shaft of femur:
+   its curvature; oblique direction; linea aspera.--Lower
+   extremity of femur: condyles; inter-condyloid notch; patellar
+   surface.--_Patella_: ligament of the patella.--Upper parts of
+   the bones of the leg.--_Head of the Tibia_: tuberosities and
+   tubercle.--Head of _fibula_.--Articulation of the knee; relation
+   of the bones in flexion and extension.--Ligamentous apparatus;
+   capsule; its laxity and extent in front, whence the facility
+   and extent of movement in flexion; its strength and shortness
+   behind, whence the limit of movement in extension.--Lateral
+   ligaments of the knee: their special mechanism.--Lateral
+   movements of the knee: crucial ligaments.--Form of the region
+   of the knee: surface below the patella; projection of patella;
+   ligament of patella.--Osseous projections on the external
+   surface and the insertion of tendons.--Simplicity of the form of
+   inner surface of the knee.
+
+
+Having studied the upper extremity of the femur with regard to the
+articulation, proportions, and contour of the region of the hips,
+we shall continue the study of this bone by examining its _shaft_
+and _inferior extremity_, and this latter part brings us to the
+_articulation of the knee_.
+
+The shaft of the femur is not straight, but is distinctly curved, with
+its convexity forward and outwards. On the living model this convexity
+may be recognised in the form of the anterior surface of the thigh,
+which is distinctly convex in front and on the outer side, the muscles
+which cover the femur in front being disposed in such a manner as to
+increase this appearance still more, as their fleshy masses are grouped
+together in the middle line of the anterior region of the thigh.
+The outward projection is most marked in cases of excessive muscular
+development, and is consequently more obvious in the male than in the
+female, and is best shown in the limbs of athletes. Again, the femur,
+in the model when standing upright, is not directed vertically, but
+rather obliquely from above downwards and inwards (Fig. 43), so that
+the superior extremities of the femur are placed at some distance,
+comparatively speaking, from each other, while the lower extremities
+come very near each other at the level of the knees. In the female
+this obliquity is more clearly marked than in the male, for the upper
+extremities of the two bones are in the former placed more widely
+apart, as we have already seen when demonstrating the relative diameter
+of the hips (inter-trochanteric diameter) in the female.
+
+  [Illustration: FIG. 43.
+
+   LEFT FEMUR (posterior view).--1, 1, linea aspera;--2, 2, its
+   external superior bifurcation;--3, its internal superior
+   bifurcation;--4, 4, its inferior bifurcations;--5, head of
+   femur;--6, depression in the head giving insertion to ligamentum
+   teres;--7, neck of femur;--8, great trochanter;--9, internal
+   surface of great trochanter;--10, small trochanter;--11,
+   external condyle;--12, internal condyle;--13, inter-condyloid
+   notch;--14, 15, tuberosities surmounting each of these condyles.]
+
+The shaft of the femur presents three surfaces--one anterior, one
+postero-external, and one postero-internal; and three borders, two
+lateral and one posterior. The two lateral borders are very rounded,
+not sharp; the posterior border, on the contrary, is very prominent,
+and forms a rough line, called the _linea aspera_ (1, Fig. 43), which
+gives insertion to a number of muscles. This linea aspera divides above
+into two _bifurcations_ slightly diverging, of which the outer one (2,
+2, Fig. 43) proceeds towards the great trochanter (_gluteal ridge_),
+and the inner one passes towards the lesser trochanter. Below, the
+linea aspera bifurcates in the same manner, one of its branches going
+to the inner, the other to the outer condyle of the femur (4, 4, Fig.
+43).
+
+The _inferior extremity_ of the femur is widely expanded, both in
+the transverse and in the antero-posterior diameter. When we examine
+the posterior aspect of this extremity (Fig. 43) we see that it is
+formed by two large prominences directed backwards, which are termed
+the _external and internal condyles_. These project laterally, and
+the inner condyle is much more prominent than the outer. The inferior
+and posterior surfaces of these condyles are smooth and covered with
+articular cartilage; between them is a deep hollow behind called the
+_inter-condyloid notch_ (13, Fig. 43). When we examine the anterior
+surface of the lower end of the femur we see that the condyles are
+united, and their smooth and continuous articular surface, covered
+with cartilage, serves to articulate with the knee-cap. This is the
+_patellar_ surface. This surface presents a depression in the middle
+line and two lateral lips, of which the external, continuous with the
+external condyle, is more prominent and rises higher than the internal,
+which is continuous with the internal condyle. These details are very
+important, for, as we shall see, the lips of the patellar surface show
+prominently beneath the skin when the knee is strongly flexed, and we
+can notice their differences in prominence and height.
+
+In forming the articulation of the knee, the lower end of the femur is
+in direct contact with the patella and the upper end of the tibia, and
+is connected (by ligaments) with the upper end of the fibula. We will
+now consider the patella and the upper extremities of the two bones of
+the leg.
+
+The _patella_, which has been compared to a disc (whence its name),
+is more nearly triangular in shape, presenting an anterior surface
+longitudinally striated and slightly convex, and a posterior surface
+moulded on the patellar surface of the femur, and forming an oval
+articular surface with a median ridge and two lateral hollows. The
+borders of the patella are three: two lateral oblique borders for the
+attachment of muscles and ligaments; and a base directed upwards,
+into which the tendon of the quadriceps extensor (and particularly
+the rectus femoris) is inserted. The apex of the bone is directed
+downwards, and attaches a strong ligament which is inserted into the
+tubercle of the tibia, and is termed the _ligament of the patella_.
+Properly speaking, this ligament is a continuation of the tendon of the
+rectus femoris muscle. The patella should be considered as a _sesamoid_
+bone, an osseous nodule developed in the substance of this tendon.
+
+  [Illustration: FIG. 44.
+
+   THE TWO BONES OF LEFT LEG (anterior view).--1, shaft of
+   tibia;--2, 3, its internal and external tuberosities;--4, spine
+   of tibia;--5, tubercle of tibia;--6, shin;--7, lower end of
+   tibia, with internal malleolus (8);--9, shaft of fibula;--10,
+   its upper end;--11, its lower end or external malleolus.]
+
+The leg, like the forearm, is composed of two bones. One, the larger
+of the two, is placed on the inner side (1, Fig. 44)--the _tibia_, or
+_shin-bone_; the other, much shorter, is situated on the outer side,
+and a little behind--the _fibula_ (9, Fig. 44). As in the case of the
+two bones of the forearm, the bones of the leg end at different levels
+above and below. Above, the tibia rises higher than the fibula, and
+alone takes a direct part in the articulation of the knee; below, the
+fibula extends lower than the tibia--so that the outer ankle (_external
+malleolus_) descends lower than the inner one. We will now for a moment
+examine the upper extremities of the two bones.
+
+The upper extremity of the tibia is expanded from side to side, to
+form the _tuberosities_ (internal and external), surmounted by two
+_articular surfaces_, external and internal (2, 3, Fig. 44), for
+articulation with the corresponding femoral condyles. The non-articular
+interval between these two surfaces presents in its centre a projection
+like a bifurcated cone which is known as the _spine_ of the tibia. In
+front of the spine and behind it are rough triangular surfaces for the
+attachment of the _crucial ligaments_.
+
+The circumference of the upper end of the tibia forms a broad rough
+margin for attachment of the capsule of the knee-joint. In front, it
+is prolonged downwards into a large triangular surface which ends in
+a rounded eminence, called the _tubercle_ of the tibia, which gives
+insertion to the ligament of the patella previously mentioned. On the
+outer side and back of the external tuberosity is a rounded facet,
+smooth and covered with cartilage, and directed mainly downwards for
+articulation with the head of the fibula (10, Fig. 44). Lastly, on
+the back of the bone is the _notch_ of the tibia, separating the two
+tuberosities from one another.
+
+The upper end of the fibula forms (10, Fig. 44) an irregular rounded
+knob. It is situated external to and rather behind the upper end of
+the tibia, and articulates, as already seen, by its upper surface with
+the outer tuberosity of the tibia. External to the articular surface
+is a smooth area for the attachment of the biceps tendon, and the
+long external lateral ligament of the knee. Behind this area is the
+_styloid process_, which gives attachment to the short external
+lateral ligament of the knee. The head of the fibula can be plainly
+felt through the skin, below and behind the head of the tibia.
+
+Such are the bony structures which take a direct (femur, tibia,
+patella) and indirect part (fibula) in the conformation of the
+knee-joint. In the living model, in the erect posture, the condyles of
+the femur rest by their inferior surfaces on the upper surface of the
+tibia, and the apposition of the articular surfaces is rendered more
+exact by the presence between the articular surfaces of the femur and
+tibia of two _semi-lunar fibro-cartilages_, which increase the depth
+of the tibial surfaces (5, 5, Fig. 46), so that the corresponding
+condyle of the femur is received into a true articular cavity. At the
+same time, the patella is closely applied to the confluent anterior
+surface of the lower end of the femur. When, on the other hand, the
+model is kneeling, or, more generally, when the leg is flexed (carried
+backwards), the patella, which is firmly fixed to the tibia by its
+ligament, glides downwards on the femur, and comes in contact with the
+lower part of its anterior surface at the same time that the posterior
+parts of the condyles in turn roll over the upper surfaces of the tibia.
+
+  [Illustration: FIG. 45.
+
+   THE ARTICULAR PARTS OF THE KNEE (antero-posterior section).--1,
+   femur;--2, tibia;--3, fibula;--4, patella;--5, rectus
+   tendon;--6, ligament of patella;--7, one of the crucial
+   inter-articular ligaments;--8, 8, one of the muscles of the
+   calf;--_a_, _a_, anterior part, and _b_, posterior part of the
+   articular capsule;--_C_, adipose mass beneath patella.]
+
+After this rapid sketch of the bones which enter into the formation
+of the knee-joint, we have now to study in detail its ligamentous
+apparatus. The ligamentous apparatus of the knee is essentially
+composed of a fibrous _capsule_, attached to the borders of the
+articular surfaces of the femur, patella, and tibia. It is strengthened
+on all sides by the tendons of muscles attached to these bones in the
+neighbourhood of the knee. Without entering into unnecessary detail, we
+must consider the arrangement of this capsule, and its disposition on
+its anterior, posterior, and lateral aspects, and then consider how it
+affects the movements of the knee-joint, rendering some movements easy
+and extensive, while it limits others or makes them almost impossible.
+
+In front (_a a_, Fig. 45) the capsule is loose and expanded and is
+mainly formed by the insertion of the quadriceps extensor muscle into
+the patella, with its continuation to the tubercle of the tibia as the
+ligament of the patella. This arrangement accounts for the ease and
+extent of the movement of flexion. In this movement, the tibia being
+carried backwards, and drawing with it the patella in the relaxed
+condition of the quadriceps extensor muscle, the capsule of the joint
+is put on the stretch. It would curtail the movement of flexion if it
+were short and compact; but the capsule at this point is so expanded
+and loose that no increase of movement on the part of the leg can cause
+any tension. Thus flexion of the knee may be prolonged until the calf
+of the leg comes in contact with the posterior surface of the thigh.
+
+Behind, the capsule of the joint is short and thick, and consists of a
+strong _posterior_ ligament. When the leg is flexed on the thigh, this
+ligament is relaxed; but as the leg passes from flexion to extension
+it becomes tense, and when extension has arrived at that point which
+brings the leg in direct continuation with the thigh, no further
+movement is possible in a forward direction, and the limb is therefore
+fixed in this position.
+
+There are, moreover, other important ligaments which act, and still
+more forcibly, in the same manner; namely, the internal and external
+lateral ligaments of the joint, which must now be considered.
+
+  [Illustration: FIG. 46.
+
+   THE KNEE state of the lateral ligaments (_a_, _b_) during
+   flexion.--1, femur;--2, condyle of femur;--3, tibia;--4,
+   fibula;--5, 5, section of semi-lunar fibro-cartilage.]
+
+  [Illustration: FIG. 47.
+
+   THE KNEE: lateral ligaments tense during extension of the leg
+   on the thigh (the distance, _a b_, is greater here than in
+   preceding figure); for the lettering, see preceding figure.]
+
+The _internal lateral ligament_ is a broad band of fibres, which passes
+from the inner tuberosity of the femur over the inner tuberosity of the
+tibia to be attached to the upper part of the _shaft_ of the tibia on
+the inner side. It helps to form the contour of the inner side of the
+knee.
+
+The _long external lateral ligament_ is a rounded cord, very strong and
+quite distinct from the capsule. Its inferior extremity is not inserted
+into the tibia, but into the head of the fibula between the insertions
+of the biceps muscle (Figs. 46, 47, _a_, _b_). The most remarkable
+characteristic of these ligaments is that their upper ends, attached to
+the lateral surfaces of the condyles of the femur, are not inserted at
+the centre of the curve of the condyles, but at a point situated more
+posteriorly (_a_, _b_, Figs. 46 and 47). During flexion these ligaments
+are therefore relaxed, but as extension is produced, as the tibia is
+carried forward on the curved surface of the condyles of the femur,
+these ligaments gradually become tense, their points of insertion
+becoming further and further apart, owing to the eccentric insertion
+of their superior extremities. When the leg reaches that position of
+extension in which it is in line with the femur, the tension of the
+lateral ligaments is such as to arrest its movement and completely fix
+the leg in relation to the thigh. This may be seen by comparing Figs.
+46 and 47. We see, then, that owing to the position of the anterior,
+posterior, and lateral ligaments of the knee-joint, the movement of
+flexion in this joint is very extensive, while that of extension is
+limited, as it cannot be prolonged further than the position which
+brings the leg into direct continuity with the thigh.
+
+These ligaments are also responsible for the amount of _lateral
+movement_ and _rotation_ possible in the knee-joint. This articulation
+being formed by two condyles, it is very evident that lateral flexion
+cannot be produced, for then it would be necessary for one of the
+condyles to become detached from the corresponding articular surface of
+the tibia. Lateral movement is thus impossible, but a slight gliding
+movement under certain conditions takes place between the condyle of
+the femur and the tibia, a movement produced by a _rotatory_ movement,
+of which the other condyle forms the centre. These slight movements
+of rotation, which contribute to the motion by which we direct the
+point of the foot outwards or inwards, are impossible during complete
+extension, when the tibia is fixed on the femur by the tension of
+the lateral ligaments and the posterior part of the capsule, and all
+the parts have already arrived at their maximum of tension. But when
+flexion occurs, and especially when the leg is at a right angle to the
+thigh, as in the seated subject, slight movements of rotation of the
+leg become possible; they are of small extent, it is true, especially
+inwards; since it is easier for the knee to take part in the movement
+which turns the foot outwards, than that which turns it inwards. This
+difference between rotation inwards and outwards is due to the presence
+within the joint of two ligaments called the _crucial ligaments_, of
+which we will only mention that they arise from the upper end of the
+tibia, between the two articular surfaces (page 136), and, crossing
+one another, are attached above to the sides of the inter-condyloid
+notch of the femur on the corresponding surface of each condyle. This
+crossing of the two ligaments is increased by the rotation of the tibia
+inwards, as this movement tends to twist them one on the other, and fix
+the tibia, so as to prevent rotation of the leg inwards. On the other
+hand, rotation outwards unwinds these ligaments and renders them more
+relaxed; so that this movement could be very extensive if the lateral
+ligaments did not prevent too great displacement between the condyle of
+the femur and the corresponding surface of the tibia.
+
+There are still in relation to the knee-joint several anatomical
+particulars which must now be examined in relation to _the external
+form_ of the living model.
+
+The posterior surface of the knee is covered by numerous muscles and
+tendons which form the boundaries of the ham or _popliteal space_;
+the study of this region will therefore be undertaken along with the
+description of the muscles of the leg and thigh. On the outer and inner
+surfaces, and on the front of the knee-joint, however, many details of
+outward form are caused solely by the osseous and ligamentous parts, to
+which we must now draw particular attention.
+
+  [Illustration: FIG. 48.
+
+   OUTLINES OF THE LOWER LIMB.--A, From behind; B, from the front;
+   C, from the outer side.]
+
+The anterior surface of the knee alters in shape in the two positions
+of extension or slight flexion, and in forcible flexion. In forcible
+flexion we notice particularly the form of the articular lower end of
+the femur (see page 134). In extension we find on the anterior surface
+of the knee, in succession from above downwards, a _flat triangular
+space above the patella_, corresponding to the tendon of the rectus
+femoris muscle; next, the _prominence of the patella_, showing clearly
+beneath the skin its triangular shape, with the base above and apex
+below; the two superior angles of the patella are frequently very
+distinct in the form of two small rounded projections. Below, _the
+ligament of the patella_ forms a longitudinal eminence in the middle
+line, reaching to the tubercle of the tibia, which is seen (in
+semi-flexion) as a large projection. But, again, we frequently perceive
+on each side of the ligament of the patella a slight, soft eminence,
+easily depressed, which corresponds to parts not yet mentioned. These
+are the thin lateral portions of the capsule (_lateral ligaments of
+the patella_), which extend from the sides of the patella and patellar
+ligament to the tibial tuberosities. These portions of the capsule
+(_c_, Fig. 45) are thin, and cover a _large mass of adipose tissue_,
+which is prolonged into the interior of the joint (as the _alar
+ligaments_), and which forms packing for the articulation on either
+side of the ligament of the patella (6, Fig. 45). When the quadriceps
+extensor muscle draws forcibly on the patella and its ligament, these
+compress this adipose mass to a much greater degree, so as to form a
+bulging on each side, and then the bilateral prominence in question is
+much more clearly marked.
+
+On the external lateral surface of the knee we note the osseous
+prominences of the _tubercle of the tibia_ (seen here in profile)
+and its _external tuberosity_; behind and below, _the head of the
+fibula_; and above, the _external condyle of the femur_. To certain
+of these prominences are attached the tendons coming from the thigh,
+marked on the external surface of the knee by three strong vertical
+bands; viz.:--in front, the tendon of the patella (seen here in
+profile); behind, the tendon of the biceps femoris, proceeding to be
+inserted into the head of the fibula; and between them the part of the
+aponeurosis of the deep fascia of the thigh, which becomes narrow and
+thickened, and forms a true tendon--_the ilio-tibial band_--attached to
+the outer tuberosity of the tibia.
+
+The form of the internal aspect of the knee is simple. Here the
+internal condyle of the femur and the corresponding tuberosity of
+the tibia form together a large regular hemispherical surface. The
+internal lateral ligament forms a broad band (page 139), which sweeps
+over the inner tuberosity of the tibia, accompanied by the tendons
+of the sartorius, gracilis, and semi-tendinosus muscles, to become
+inserted into the upper portion of the shaft of the tibia. The ligament
+and tendons soften the outlines of the bones, and give a rounded
+contour to the inner side of the knee.
+
+
+
+
+                             CHAPTER XII.
+
+                      THE LEG, ANKLE-JOINT, FOOT.
+
+   The bony structure of the leg.--_Tibia_ and _fibula_:
+   tibio-fibular articulation; absence of mobility in the fibula
+   (differences between the leg and forearm: between the foot and
+   hand, also in the quadrumanous monkeys). Inferior extremities
+   of these bones: _tibio-fibular articulation_; the malleoli:
+   comparison of the internal and external malleoli with regard
+   to length, situation, and form.--The skeleton of the foot:
+   _tarsus_, _metatarsus_, and _toes_.--Importance of the bony
+   structure of the tarsus and its influence on the form of the
+   foot: construction and arrangement of tarsus, posterior half:
+   anterior half.--Articulation of the leg with the foot; movements
+   of the foot.
+
+
+The two bones of the leg are placed, as we have previously seen (page
+135), parallel to each other, the _tibia_ on the inner side, the
+_fibula_ on the outer side and somewhat behind (Fig. 49). The _tibia_
+can be felt beneath the skin in its whole length. Its _shaft_ is
+triangular in section, and therefore presents three surfaces and three
+margins (1, Fig. 49): an internal surface covered only by the skin and
+appearing superficially as a long flat surface, broader above where it
+looks a little forward, and inclining directly inwards at its inferior
+part, where it becomes continuous with the prominence of the inner
+ankle or internal malleolus (Fig. 50, page 150). The external surface
+is slightly concave in order to lodge the antero-external muscles of
+the leg, of which the principal is the tibialis anticus; below, this
+surface inclines forwards, following the course of the tibialis muscle,
+which, from the antero-external region of the leg, is directed towards
+the inner border of the foot (Fig. 50, page 150). The posterior surface
+of the tibia is entirely covered by the strong and numerous muscles of
+the posterior region of the leg. Finally, of the three margins of the
+shaft of the tibia the anterior is particularly prominent, and is known
+by the name of the _crest of the tibia_ or _shin_ (6, Fig. 49).
+
+The _fibula_ appears superficially, as already seen, in the region
+of the knee, at its upper end. Its lower end is also obviously
+subcutaneous at the outer ankle, where it forms the _external
+malleolus_ (9, Fig. 49). The shaft of the bone is long and slender, and
+is prismatic in form. It is curved from above downwards and forwards,
+and downwards and inwards. It serves the purpose of a strengthening
+bar for the tibia, at the same time that it increases the area for
+the attachment of the muscles of the leg. The shaft of the fibula is
+surrounded on all sides by these muscles.
+
+  [Illustration: FIG. 49.
+
+  BONES OF THE LEG (front view).]
+
+The two bones are separated throughout their entire length by an
+interval called the _interosseous space_ (Fig. 49), broader above than
+below, and filled up by a fibrous membrane (_interosseous membrane_),
+which, passing from one bone to the other, still further increases
+the area for attachment of the muscles of the leg. Above, the fibula
+articulates with the postero-external surface of the superior extremity
+of the tibia, and this superior _tibio-fibular articulation_ possesses
+a very slight gliding movement, exercised chiefly through the action of
+the biceps muscle in external rotation at the knee-joint. Below, the
+fibula is attached to the corresponding part of the tibia by a strong
+_interosseous ligament_, forming a symphysis, or _synarthrodial joint_.
+This _inferior tibio-fibular_ articulation has hardly any mobility:
+it only gives a certain amount of elasticity to the ankle-joint, into
+which the foot is received. We see, therefore, that there is, with
+regard to mobility, a great difference between the bones of the leg
+and those of the forearm; in the forearm the radius is moveable on the
+ulna, and can turn in such a manner as to cross the latter, and produce
+the movements of pronation and supination of the hand. Between the
+fibula and the tibia there is no movement of the kind; the foot is not
+capable of any movement which may be compared to that which takes place
+in the hand during pronation and supination. We may say that it is the
+same with monkeys, in the class called quadrumana; they have not the
+power of pronation and supination of the foot, which, from this point
+of view, and also in every other respect, is properly speaking a foot
+and not a posterior hand, as their ancient name of _quadrumana_ would
+lead us to suppose.
+
+_Ankle-joint._--By their junction the inferior extremities of the
+tibia and fibula constitute an articular cavity, which forms the
+ankle-joint, by their articulation with a bone of the tarsus--the
+_astragalus_. This _tibio-fibular_ cavity possesses three sides, of
+which two, the superior and internal, are formed by the tibia, and one
+only, the external, by the fibula; the two lateral walls correspond
+to the two osseous parts which form the prominences of the ankles and
+which are known by the name of _malleoli_ (_malleus_, a hammer). They
+are distinguished as the _internal or tibial_ and _external or fibular
+malleoli_ (Fig. 49, page 147). As the internal ankle or malleolus (8)
+is of a form and situation very different to that of the external (11),
+it is important to note here the configuration of the bones by which
+the subcutaneous prominences are explained.
+
+The malleoli differ in their _level_, in their _situation_, and
+finally in their _form_ (Figs. 50, 51). First, we see at a glance that
+the external or fibular malleolus (11) descends much lower than the
+internal malleolus (8). Second, with regard to the transverse plane
+of the two malleoli, just as the shaft of the fibula is situated
+behind and to the outer side of the tibia, so the same position is
+maintained by the inferior extremities of the two bones, and the
+external malleolus is on a plane posterior to the internal malleolus.
+A transverse line which passes through the centre of the internal
+malleolus, passes outwards in front of the anterior border of the
+external malleolus; and, on the other hand, a transverse line, passing
+through the centre of the external malleolus, passes inwards behind
+the posterior border of the internal malleolus. Thirdly, with regard
+to the differences of form, these are the direct result of the shape
+of the osseous parts. The malleolar portion of the tibia, or internal
+malleolus, is square, presenting a horizontal inferior border, and
+two vertical borders--one anterior, the other posterior. On the
+contrary, the malleolar portion of the fibula, or external malleolus,
+is triangular in shape, or rather like the head of a serpent; it
+terminates below in a pointed extremity, formed by the convergence of
+the two oblique borders--one anterior, the other posterior--of which
+the anterior is the more sloping.
+
+  [Illustration: FIG. 50.
+
+  OUTLINE OF ANKLE AND FOOT (inner side).]
+
+  [Illustration: FIG. 51.
+
+  OUTLINE OF ANKLE AND FOOT (outer side).]
+
+Before entering into a study of the articulation of the leg with the
+foot, or _ankle-joint_, we must glance at the bony structure of the
+foot as a whole, so as to understand properly the significance of the
+position of one of the bones (_astragalus_) in relation to this joint.
+
+  [Illustration: FIG. 52.
+
+  OUTLINES OF THE FOOT (A, Dorsum; B, Sole).]
+
+Just as the hand is composed of three sets of bones--the carpus,
+metacarpus, and fingers--so also the foot is composed of a similar
+series--the _tarsus_, _metatarsus_, and _toes_; but while in the hand,
+where the function is principally that of prehension, the fingers are
+long and the carpus very short, in the foot, which serves as a base
+of support, the toes are comparatively short, while the tarsus, which
+corresponds to the carpus, is of considerable size; it forms, in fact,
+one-half of the length of the foot. In order to understand the form of
+the foot and its mechanism it is necessary to make a particular study
+of the bones which compose the tarsus.
+
+As the carpus in the hand is formed by two rows of bones, so also the
+tarsus is composed of two groups. In the hand the carpal bones are
+grouped in two more or less transverse rows. In the foot, on the other
+hand, the rows of tarsal bones are longitudinally arranged; and the
+inner row overlaps the outer row in relation to the back part of the
+tarsus. There are two bones in the outer row: the _calcaneum_ or _os
+calcis_ behind, which forms the prominence of the heel and rests on
+the ground below: and the _cuboid_, articulating with it in front and
+carrying anteriorly the two outer metatarsal bones and the two outer
+toes. The inner row consists of five bones: (1) the _astragalus_ or
+_talus_ behind, which articulates with the bones of the leg and helps
+to form the ankle-joint above, which rests below on the upper surface
+of the calcaneum, and which articulates in front with the _navicular_
+bone; (2) the navicular or scaphoid bone; and in front of this the
+three _cuneiform_ bones (_internal_, _middle_, and _external_), which
+lie above and internal to the cuboid bone, and carry the three inner
+metatarsal bones and the three inner toes.
+
+  [Illustration: FIG. 53.
+
+   THE BONES OF THE FOOT, seen from the dorsal surface.--1,
+   astragalus (with its head and neck, 2);--3, calcaneum;--4,
+   scaphoid;--5, internal cuneiform;--6, middle cuneiform;--7,
+   external cuneiform;--8, cuboid;--9, the metatarsus;--10, 11, the
+   two phalanges of the great toe;--12, 13, 14, the first, second,
+   and third phalanges of the other toes.]
+
+After this brief sketch of the tarsus, and before entering into the
+details of the configuration of its parts and the whole taken together,
+having seen the particular place occupied by the _astragalus_, we
+must study its articulation with the tibia and fibula. The part of the
+astragalus which is received into the cavity between the malleoli, is
+formed by the posterior three-fourths (1, Fig. 53) of the superior part
+of the bone, separated from the anterior fourth by a narrow portion
+called the neck (2, Fig. 53). This articular part is in the form of a
+pulley, with the antero-posterior groove hardly perceptible, but the
+lips are prolonged over the sides of the bone, and come in contact
+with the corresponding parts of the internal and external malleoli. It
+is readily seen (Fig. 53) that the articular surface of the astragalus
+is considerably wider in front than behind. The same is seen in
+the shape of the lower end of the tibia. The _tibio-astragaloid
+articulation_ permits movement chiefly in the anterio-posterior
+plane, namely, movement forward (flexion of the foot) and backwards
+(extension). During flexion of the foot on the ankle the astragalus
+is received in the malleolar cavity as in a vice, and the result is
+that no lateral movement is possible. When, however, the foot is
+extended, and the toes are pointed, the narrower part of the articular
+surface of the astragalus comes into relation with the wider portion
+of the inter-malleolar articular surface, and the result is that in
+this position a certain amount of lateral movement of the foot at the
+ankle-joint is permitted, aided, it is true, by gliding movements
+taking place among the tarsal bones themselves. Of the movements of
+flexion and extension, that of extension is the most free, as it may
+be continued until the axis of the foot becomes continuous with that
+of the leg, and here it is arrested by the meeting of the posterior
+border of the joint with the projections on the posterior border of the
+astragalus; but the movement of flexion by which the dorsal surface
+of the foot is brought near the anterior surface of the leg is more
+limited, for it is impossible to cause the foot to make with the leg an
+angle less than forty-five degrees, opening upwards and forwards. This
+is accounted for by the shape of the articular surfaces. In proportion
+as flexion is produced, the larger part of the articular surface of
+the astragalus is wedged into the malleolar cavity; thus the movement
+of flexion is arrested, and the foot is fixed. We cannot carry flexion
+further without bursting asunder the tibio-fibular joint, just as we
+should split a piece of wood by driving violently into it a wedge
+larger than the cavity to be filled.
+
+
+
+
+                             CHAPTER XIII.
+
+                               THE FOOT.
+
+   Bony structure of the foot.--Union of bones of tarsus;
+   astragalus and calcaneum (canalis tarsi, or tunnel of the
+   tarsus); astragalar articulations, inferior calcaneo-scaphoid
+   ligament; special functions of astragalus in the mechanism of
+   the foot.--The other articulations of the tarsus, and their
+   movements. _Metatarsus_ and _Metatarsal_ bones; importance of
+   fifth metatarsal with regard to form.--The _toes_ and their
+   _phalanges_.--Skeleton of the foot as a whole; form of the
+   foot.--Plantar arch.--_Proportions of the lower limb_; the foot
+   as a common measure of the lower limb and the height.
+
+
+We will now examine briefly the bones of the _tarsus_, especially with
+regard to the details which mark their articulations. The inferior
+surface of the _astragalus_ presents two articular facets, separated by
+a deep, oblique groove. These two facets correspond with two similarly
+situated on the upper surface of the calcaneum. The astragalus thus
+rests upon the calcaneum, but it is supported on the inner side by a
+projection of the calcaneum, known by the name of the _sustentaculum
+tali_; and the anterior facet for the astragalus is to be looked for
+on the upper surface of this projection (Fig. 53, page 153). The
+two facets of the calcaneum are also separated by a deep groove. It
+follows, therefore, that when the astragalus is in its place, the
+groove of the astragalus and the calcaneum meet and form a kind of
+tunnel, which is called the _cavity of the tarsus_, or _canalis tarsi_.
+This cavity is filled up during life by a strong ligamentous band,
+which attaches the astragalus to the calcaneum, and is called the
+_interosseous ligament_. Placed between the two calcaneo-astragaloid
+articulations, one in front of it and the other behind, the ligament
+forms a sort of pivot, around which the movements between the
+astragalus and the calcaneum take place. It is round these joints as a
+centre that the movements take place by which the foot as a whole is
+turned inwards or outwards, and so that its outer and inner borders are
+elevated.
+
+We have next to consider the articulations of the calcaneum and
+astragalus with the other bones of the tarsus. The articulation of
+the anterior extremity of the calcaneum with the posterior surface of
+the cuboid presents an interlocked arrangement which is surrounded
+by strong ligaments, especially on its lower plantar surface (the
+_inferior calcaneo-cuboid ligaments_, or _long and short plantar
+ligaments_), so that between the calcaneum and the cuboid only a
+slight gliding movement takes place, and to all intents and purposes
+these two bones form one elastic piece. The plantar ligaments from
+their strength have an important influence on the maintenance of
+the arch of the foot. The cuboid bone articulates in front with the
+metatarsal bones of the fourth and fifth toes, so helping to complete
+the outer part of the contour of the foot. On the inner side of the
+foot the bones completing the tarsus in front of the astragalus are
+the _navicular_ (or _scaphoid_), and the three _cuneiform_ bones,
+_internal_, _middle_, and _external_, which in turn are related to the
+inner three metatarsal bones. The _astragalo-scaphoid articulation_
+deserves the closest attention. The head of the astragalus, so called
+from its prominent rounded shape, articulates with the navicular bone,
+which is prolonged internally into a prominent _tubercle_. Between the
+sustentaculum tali and this tubercle a very powerful ligament passes,
+on which a part of the astragalus rests. The ligament is called the
+_inferior calcaneo-scaphoid_ ligament, or _spring_ ligament, and by
+its means an articulation is completed between the three bones--the
+_astragalo-calcaneo-scaphoid_ joint. The whole weight of the body may
+be supported by the inferior calcaneo-scaphoid ligament, which thus
+serves an important purpose in supporting the arch of the foot. This
+is the ligament which gives way in flat-foot. By these articulations
+the foot possesses the power of lateral movement, by which the toes
+are carried inwards or outwards, and the outer border of the foot is
+elevated and the inner border is depressed, or the reverse. On the
+other hand, the movements of flexion and extension take place chiefly
+at the ankle-joint, the articulation, previously explained, of the
+astragalus with the tibia and fibula.
+
+  [Illustration: FIG. 54.
+
+   RIGHT FOOT (internal border).--1, 2, 3, 4, calcaneum;--5, 6, 7,
+   astragalus;--8, posterior calcaneo-astragaloid articulation;--9,
+   head and neck of the astragalus;--10, 11, navicular or
+   scaphoid;--12, astragalo-scaphoid articulation;--13, 14,
+   internal cuneiform;--15, articulation of the internal cuneiform
+   with the scaphoid;--16, the articulation of the internal
+   cuneiform with the metatarsal bone of the great toe;--17, the
+   middle cuneiform;--18, its articulation with the scaphoid;--19,
+   the first metatarsal bone;--20, the second metatarsal bone;--21,
+   the articulation of the second metatarsal bone with the
+   cuneiform bones;--22, sesamoid bone;--23, 24, the phalanges of
+   the great toe; 25, 25, phalanges of the other toes.]
+
+The navicular or _scaphoid_ bone articulates in front with the three
+_cuneiform_ bones, and the cuneiform bones articulate with each other
+by facets which are flat, but present rough surfaces towards their
+inferior or plantar portions intended for interosseous ligaments.
+Similar articulations exist externally between the scaphoid and
+external cuneiform, and the cuboid bone. It is sufficient to say that
+in all these articulations a slight gliding movement takes place, just
+sufficient to give a certain elasticity to the plantar arch, which
+they contribute to form. We may point out the peculiarities that are
+to be noted in each of these bones: the _scaphoid_ or _navicular_ bone
+is concave behind, convex in front, and is prolonged into a prominent
+tubercle, which can be felt at the middle of the inner border of the
+foot; the _cuboid_ is quadrilateral or pyramidal in form, and has an
+oblique groove (14, Fig. 55) on its inferior or plantar surface, which
+contains the tendon of the _long peroneal_ muscle (see below); finally,
+the three _cuneiform_ bones are distinguished, counting from within
+outwards, as the _internal_, _middle_, and _external_ cuneiform (Fig.
+53, page 153); the middle cuneiform (6) is smaller than the others,
+and does not extend so far forward, so that in relation to it the line
+of the tarso-metatarsal joints forms a notch opening into the tarsus,
+into which the posterior extremity of the second metatarsal bone is
+received.
+
+In front of the tarsus is found the _metatarsus_, corresponding to the
+metacarpus of the hand, while the toes correspond to the fingers. We
+have only a few words to say about those portions of the skeleton which
+resemble the corresponding parts of the hand.
+
+  [Illustration: FIG. 55.
+
+   RIGHT FOOT (external border).--1 to 6, the calcaneum;--7, the
+   tibial surface of the astragalus;--8, the lateral facet of the
+   astragalus for the external malleolus;--9, the tunnel of the
+   tarsus (canalis tarsi);--10, the posterior calcaneo-astragaloid
+   articulations;--11, head and neck of the astragalus;--12,
+   the scaphoid;--13, cuboid;--14, commencement of the groove
+   on the inferior surface of the cuboid (for the tendon of the
+   long peroneus muscle);--16, external cuneiform;--17, middle
+   cuneiform;--18, the five metatarsal bones with their posterior
+   extremities (19);--20, 21, 22, 23, fourth, third, second, and
+   first metatarsal bones;--24 to 25, phalanges of the toes.]
+
+The metatarsal bones, five in number, are long bones, each composed
+of a prismatic shaft and two extremities, one posterior or tarsal,
+more or less wedge-shaped; the other anterior or digital, forming a
+rounded, globular head which articulates with the base of a phalanx.
+The metatarsal bones are placed parallel side by side, but that of the
+great toe is not markedly shorter than its fellows like the metacarpal
+bone of the thumb, and the great toe does not possess anything like the
+same amount of mobility as the thumb. It is further directed straight
+forward so as to complete the straight line of the inner border of
+the foot. With regard to particular details, it is necessary to note
+in the first metatarsal (19, Fig. 54) its large size, in the second
+(22, Fig. 55), its greater length, for it passes behind the others (in
+entering into the notch which corresponds to the middle cuneiform), and
+it also exceeds them in length, so that the second toe is as a rule a
+little longer than the rest. In the fifth we must note the form of its
+tarsal extremity, prolonged behind into a process (19, Fig. 55) which
+appears as a prominence at the middle of the outer border of the foot,
+and gives insertion to the _short peroneal_ muscle. Lastly, it may
+be observed that all the metatarsal bones except the first are sloped
+inwards and forwards, to point as it were towards the great toe.
+
+The phalanges of the toes (Figs. 54 and 55) resemble in number and
+arrangement the corresponding bones of the hand, only they are much
+shorter, especially those of the little toe, the two last of which are
+reduced to small osseous nodules, so that the fifth toe is always much
+shorter than the rest. The names of the phalanges are the same as in
+the hand (page 93).
+
+_The Foot as a whole._--The skeleton of the foot forms an _arch_ which
+presents two curves or concavities, one antero-posterior, the other
+transverse. The _sole_ of the foot forms a hollow which extends from
+the posterior extremity of the calcaneum to the anterior extremity of
+the metatarsal bones; but this plantar hollow is much more elevated
+on the inner side (Fig. 54) than on the outer side (Fig. 55). It is
+necessary, in other words, in order to understand the general form of
+the foot, to consider that its _dorsal surface_ looks upwards _and
+outwards_, and the sole _downwards and inwards_. The _outer border_ is
+thin, and comes almost in contact with the ground, its _inner border_
+is thick and is raised from the ground.
+
+The skeleton of a well-articulated foot placed upon a horizontal
+surface comes in contact with the flat surface only by the posterior
+extremity (_tuberosity_) of the calcaneum (heel), and by the heads
+of the metatarsal bones (the balls of the toes, Fig. 52, page 151).
+When the foot is covered with its soft parts these points of contact
+are scarcely changed; for, except at the heel and the balls of the
+toes, we see that the greater part of the outer border of the foot
+touches the ground but lightly, unless the subject is carrying a heavy
+load, which, pressing upon the plantar arch, brings its elasticity into
+play and slightly flattens it. We shall mention later on the special
+structures (ligaments and tendons) which act as cords which bend the
+bow and maintain the plantar arch.
+
+_Proportions of the Lower Limb._--As we have already inquired into the
+ratio of proportions of the hand and upper limb, we shall now see if
+the foot can furnish any measurements relative to the _proportions of
+the body_. We find that we can make the foot, no more than the hand,
+a common measure for the body in general and for the inferior limb in
+particular. We must confine ourselves to such measurements as will
+apply to the average subject. Thus it is easy to perceive upon the
+skeleton that the distance from the upper margin of the head of the
+femur to the inferior border of the internal condyle is equal to twice
+the length of the foot; but this has no practical value--it cannot be
+used on the living body, as it is difficult to recognise the level
+of the upper part of the head of the femur. If, instead of the head
+of this bone, we take the superior border of the great trochanter (a
+part easily felt beneath the skin), we find that the length from the
+superior border of the great trochanter to the inferior border of the
+external condyle scarcely ever measures the length of two feet, as the
+great trochanter is upon a considerably lower level than the head of
+the femur.
+
+The leg, including the thickness of the foot, is not as much as twice
+the length of the foot--that is, the distance from the lower border of
+the internal condyle of the femur to the ground (or the sole of the
+foot); but it is interesting to observe that in general the length of
+the leg, plus the thickness of the foot, is equal to the distance from
+the great trochanter to the lower border of the external condyle; in
+other words, the centre point of the lower limb (starting from the
+great trochanter) corresponds exactly to the line of the knee.
+
+When we compare the length of the foot with the leg, beginning from
+below upwards, we find a regular proportion, and one of practical
+interest--viz. that the line from the ground to the middle of the
+patella usually measures twice the length of the foot.
+
+As a common measure of the height of the body, the foot does not give
+us a result that can be expressed by an even number. From the numerous
+researches of Leger on this question, the length of the foot is
+generally contained 6⅓ times in the total height. However, this number
+presents an interesting fact when we express this proportion by taking
+the third part of the foot for a unit; 6⅓ feet forming nineteen thirds
+of the foot, we see that the height of the body contains nineteen
+thirds of the foot. It is interesting to observe that the number 19 is
+precisely that which expresses the proportion that the middle finger
+bears to the height in the Egyptian canon, according to Charles Blanc.
+
+With regard to the foot itself, we need only say that the
+tarso-metatarsal line offers, on the skeleton, a simple means of
+dividing the foot. This line is oblique from within outwards and
+backwards; its inner extremity at the base of the first metatarsal bone
+divides the foot into an anterior and posterior half, while its outer
+extremity, at the base of the fifth metatarsal bone, divides it into a
+posterior one-third and anterior two-thirds.
+
+
+
+
+                             CHAPTER XIV.
+
+                              THE SKULL.
+
+   The bony structure of the _head_; division into _cranium_
+   and _face_. Study of the vault, or skull-cap. _Occipital_
+   bone.--_Parietal_ bone (parietal eminence and temporal
+   ridge).--_Frontal_ bone (frontal eminences, superciliary ridges:
+   nasal eminences: supra-orbital arches).--_Temporal_ bone:
+   mastoid process; zygomatic process.--Sutures of the skull:
+   sagittal suture; lambdoid suture; sphenoidal sutures.--General
+   form of skull: long heads; round heads.--Cephalic indices;
+   dolichocephalic, brachycephalic, and mesaticephalic skulls.
+
+
+The _skeleton of the head_ is formed of two parts intimately united
+to each other: one above and behind, formed for the most part of flat
+bones, simple in form, and called the _cranium_, containing the brain:
+the other below and in front, consisting of numerous bones, complex in
+shape, and constituting the bony structure of the _face_. The facial
+bones form the boundaries of the cavities which lodge the principal
+organs of sense and the apparatus of mastication.
+
+The _cranium_.--The cranium forms an egg-shaped box with its long axis
+directed from before backwards. It may be examined from its _base_,
+which we need not study here, or from above or from the side. The
+bones which enter into its construction are eight in number, viz. the
+_sphenoid_ in the base and side wall, the _occipital_ behind, the
+_frontal_ in front, the two _parietal_ above, and the two _temporal_
+bones on the sides.
+
+  [Illustration: FIG. 56.
+
+   THE SKULL (lateral surface).--1, frontal bone;--2, parietal;--3,
+   occipital;--4, temporal;--5, the great wing of the sphenoid;--6,
+   coronal suture;--7, lambdoidal suture;--8, 9, parieto-temporal
+   suture;--10, spheno-parietal suture--11, spheno-temporal
+   suture;--12, fronto-sphenoidal suture;--13, curved line limiting
+   the temporal fossa;--14, 15, 16, malar bone;--18, the superior
+   maxillary bone, with the infra-orbital foramen (19);--20, 21,
+   22, the bones of the nose;--23, the lachrymal groove;--24, the
+   nasal eminence;--25, the inferior maxillary bone;--26, the
+   mental foramen;--27, the angle of the jaw.]
+
+The _occipital_ bone (3, Fig. 56) forms the whole posterior part of the
+base and vault of the skull. The bone possesses two distinct parts,
+inferior and superior. The _inferior_ part is more or less horizontal,
+and is pierced by a large foramen (_foramen magnum_) through which the
+cavity of the cranium communicates with that of the vertebral canal.
+In front of this foramen is the _basilar process_ of the occipital
+bone; upon each side are the _occipital condyles_, by which the skull
+articulates with the vertebral column--namely, with the lateral masses
+of the atlas (pp. 31, 32). The _superior_ part (3, Fig. 56), called
+the _squamous_ or _shell-shaped portion_ of the bone, is more or less
+triangular in form, with the apex directed upwards. Its borders are
+hollowed out into numerous irregular denticulations, which work in
+with similar denticulations on the posterior borders of the parietal
+bones (7, Fig. 56); and assist in forming the _lambdoidal suture_.
+The external or posterior surface is crossed about its middle by a
+_semicircular_ crest (_the superior curved lines_) of which the centre
+forms a prominence called the _external occipital protuberance_. This
+prominence is placed below the most projecting point of the back of
+the skull. The superior curved lines separate the outer or posterior
+surface of the occipital bone into an upper smooth part, belonging to
+the vault, which is covered by the scalp, and a lower rough surface, to
+which the muscles of the neck are attached.
+
+The _parietal_ bones (2 and 13, Fig. 56) are placed on each side of
+the vault of the skull in front of the occipital bone. Quadrilateral
+in shape, each bone presents four denticulated borders, of which the
+superior articulates with the parietal of the opposite side, the
+posterior with the occipital (7, Fig. 56), the anterior with the
+frontal (6), and the inferior, which is concave (8, Fig. 56), with
+the temporal and (slightly) with the sphenoid bone. The parietal bone
+presents two points for notice on its external surface--1, near its
+centre a projection called the _parietal eminence_, better marked in
+young subjects than in the adult, which represents the place where the
+ossification of the bone commences; 2, below this prominence a curved
+line, the _temporal ridge_, slightly rough (13, Fig. 56), which limits
+the temporal fossa and gives attachment to the temporal fascia.
+
+  [Illustration: FIG. 57.
+
+   FRONTAL BONE (anterior surface).--1, the frontal eminences;--2,
+   2, superciliary ridges;--3, nasal eminences;--4, 4,
+   supra-orbital notches;--5, 5, 6, 6, internal and external
+   angular processes;--7, 7, nasal notches;--8, nasal spine;--9,
+   9, orbital plates;--11, the superior border;--12, the lateral
+   borders.]
+
+The _frontal bone_, a single bone (1, Fig. 56), like the occipital,
+presents, like it, a vertical and a horizontal part. The latter belongs
+to the base of the skull and to the face (9, 9, Fig. 57), and forms
+the roof of the cavity of the orbit (see below). The vertical part
+forms the anterior and superior wall of the cranium. It has a rounded
+superior border (11, Fig. 57) which articulates by its denticulated
+edge with the parietal bones and forms the _coronal suture_ (6, Fig.
+56). The anterior superficial surface forms the forehead, and upon it
+we have to notice the following points:--1, the _frontal eminences_ (1,
+1, Fig. 57), better marked in young subjects and in females than in
+the adult male; 2, below these, the _superciliary ridges_ (2, 2, Fig,
+57), which are directed obliquely downwards and inwards, to end in two
+prominent bosses called the _nasal eminences_. These prominences are
+best marked in the adult, and owe their prominence to the fact that
+the thickness of the bone is hollowed out in this situation into two
+cavities called the _frontal sinuses_, which become more developed as
+the subject advances in age; 3, at the lower border of this part of the
+bone are the _supra-orbital arches_ (4, 4, Fig. 57), at the margin of
+the orbit. Curved, with the concavity downwards, each of these arches
+forms on the outer side an _external angular process_ (6, 6, Fig. 57),
+which articulates with the malar, or cheek-bone (15, Fig. 56), and on
+the inner side an _internal angular process_ (5, 5, Fig. 57) which
+articulates with the nasal process of the upper jaw. Between the two
+internal angular processes is a median rough space called the _nasal
+notch_ (7, Fig. 57), into which are received the _nasal_ bones (22,
+Fig. 56). Each supra-orbital arch presents, at the junction of its
+middle and inner thirds, a small notch called the _supra-orbital notch_
+(Fig. 57).
+
+The _temporal bones_, one on each side of the skull (4, 11, and 31,
+Fig. 56), are very complex in shape, but we shall study here only one
+portion. Each temporal bone is composed of two parts, one belonging
+to the base, and another belonging to the lateral wall of the skull;
+the part belonging to the base forming a pyramidal mass of very dense
+bone, called the _petrous portion_, which contains the delicate organs
+of the internal ear; while the part belonging to the lateral wall of
+the skull (4, Fig. 56) rises up as an irregular osseous disc from the
+base of the petrous portion of the bone. An orifice, the _external
+auditory meatus_ which leads into the petrous bone, is found about
+its centre (31, Fig. 56). Taking this orifice of the auditory canal
+as a centre, we find on the external surface of the temporal bone--1,
+behind the auditory canal the _mastoid portion_ of the bone (33, Fig.
+56), which articulates with the parietal and occipital bones, and is
+prolonged downwards as a conical process in the shape of a nipple
+(μαστός, a nipple) called the _mastoid process_; 2, above the auditory
+canal, the _squamous portion of the temporal bone_ (4, Fig. 56), a
+shell-like bone with a rounded border articulating with the inferior
+border of the parietal bone (8, Fig. 56). In front is a process (20,
+Fig. 58) which is directed horizontally towards the face and joins the
+malar bone (16, Fig. 56). This process, connecting the cranium with the
+face, is called the _zygomatic process_ (ζυγός, a yoke), and it forms
+with the corresponding part of the malar bone the _zygomatic arch_.
+The zygomatic process rises from the temporal bone by two roots (Fig.
+57), of which one sweeps backwards above the orifice of the external
+auditory canal and helps to form the temporal ridge; the other extends
+as a rounded ridge transversely inwards towards the base of the skull,
+and as the _eminentia articularis_, forms the anterior limit of the
+_glenoid cavity_, into which the condyle of the lower jaw is received.
+Finally, below the auditory canal, the temporal bone gives origin to
+the _styloid process_ (32, Fig. 56), long and slender, which gives
+attachment to certain ligaments and muscles of the neck.
+
+The _sphenoid bone_ is one of the most important in the construction
+of the cranium, although as it chiefly occupies the middle of the
+base of the skull, it is not very obvious on the surface. It is the
+_great wing_ of the sphenoid bone which assists in the formation of the
+_temporal fossa_.
+
+The bones of the cranium articulate with one another by denticulated
+borders, to which the name of _sutures_ is given. As the artist needs
+to study the skull not only with regard to its superficial form,
+but also as an _object_ which figures frequently as an accessory in
+still-life compositions, and as a true representation of these sutures
+contributes to give to the skull its exact physiognomy, we must not
+leave the subject without carefully pointing them out. It is necessary
+for our purpose to examine the skull on its upper and its lateral
+surfaces.
+
+The upper surface of the skull presents a suture in the middle
+line, antero-posterior and inter-parietal, called the _sagittal
+suture_. Behind, on a level with the superior angle of the occipital
+bone (7, Fig. 56), this median suture becomes continuous with the
+occipito-parietal suture to which the name of the _lambdoid suture_ is
+given-because it resembles the form of a Greek lambda (=Λ=). In front,
+the sagittal suture is met by the parieto-frontal suture (6, Fig. 56),
+which forms a curved line, to which has been given the name of the
+_coronal suture_.
+
+On examining the skull on one of its lateral surfaces, we see that the
+sutures form in this situation a more complex design, because of the
+articulations of the bones entering into the formation of the _temporal
+fossa_ (5, 10, 11, 12, Fig. 56). This fossa is formed by the parietal,
+squamous portion of the temporal, frontal, and great wing of the
+sphenoid bones. It is limited: below by the zygomatic arch (malar and
+temporal), and above by the curved line of the temporal ridge, which
+marks the temporal, parietal, and frontal bones. The suture formed
+within the fossa, at a point called the _pterion_, is roughly =H= or
+=K=-shaped, and is occasioned by the contiguous articulations of the
+parietal, sphenoid, frontal, and squamous portion of the temporal bones.
+
+We have said that the general form of the skull is egg-shaped, with its
+greater extremity behind. It is, however, a common observation that the
+skull may differ remarkably from what may be termed the normal shape.
+It may be excessively high, or low; excessively prolonged backwards
+or forwards, or the reverse. One of the best-marked and constant
+variations is in the ratio of width to length, from which the _cephalic
+index_ is derived. This may be an individual peculiarity: for instance,
+of two brothers, one may be round-headed, the other long-headed.
+Or it may be a racial character: for example, the black races are
+long-headed, the yellow races are round-headed, and the white races
+have a cephalic index which may be one or the other, or intermediate
+between the two extremes.
+
+The cephalic index (index of breadth of the skull) is an important term
+in physical anthropology.
+
+As we have previously explained, respecting the proportions of the arm
+and forearm (_brachial index_, page 100), we understand by the name of
+index the number which indicates the proportion between a short and a
+greater length, the latter being considered as equal to 100--that is
+to say, the figures obtained by direct measurement being reduced to
+a decimal proportion. We find that in certain skulls the transverse
+diameter is relatively very short, seeing that it is represented by an
+index of 75 or less; and such skulls are known as _dolichocephalic_
+(δολιχός, lengthened; κεφαλή, head). Others present a transverse
+diameter which approaches the antero-posterior, since it is represented
+by an index of 80 or more, the antero-posterior measurement being
+100. This cephalic index of 80 or more is called _brachycephalic_
+(βραχύς, short). Between these two types are the heads of intermediate
+form called _mesaticephalic_, of which the cephalic index is from
+75 to 80. The importance of dolichocephalic, mesaticephalic, and
+brachycephalic types of skull in relation to racial characters has no
+doubt been exaggerated; but the fact remains that certain races are
+dolichocephalic, and that certain other races are brachycephalic. A
+greater difficulty arises in regard to mesaticephalic skulls, which
+are, after all, in a sense only “averages,” and which, occurring as
+they do so commonly in the Indo-European race, suggest that either
+they are due to individual peculiarity or to the mingling of racial
+characters--in either case weakening the value of skull measurements in
+the investigation of races.
+
+
+
+
+                              CHAPTER XV.
+
+                               THE FACE.
+
+   The bony structure of the face.--_Orbital cavities_: margins;
+   cavities.--_Nasal fossæ_: anterior orifice.--Prominence of the
+   _cheek_; malar bone and its processes.--_Upper jaw._--_Lower
+   jaw_; body; ramus; sigmoid notch, coronoid process, and condyle:
+   variations with age.--The _teeth_: parts; names (incisors,
+   canines, premolars, molars), number; relative dimensions of
+   incisors.--Articulation of the lower jaw.--The face and skull
+   as a whole with regard to form.--_Facial angle of Camper_; its
+   measure; its proper value according to race; its exaggeration
+   in the antique.--Proportions: the head as a common measure:
+   law of eight heads; variations according to the height of the
+   individual; point which corresponds to the middle of the body.
+
+
+_The Face._--Instead of describing the bones of the face separately we
+will group them together around the cavities which they circumscribe
+and the prominences which they form. We will therefore study
+successively the _cavity of the orbit_, the orifice of the _nasal
+fossæ_, the prominence of the _cheek-bone_, and, lastly, the region of
+the _mouth_, along with which we will describe the _teeth_, the _lower
+jaw_, and its articulation with the base of the skull.
+
+_The orbits._--The orbits are two cavities situated symmetrically one
+on each side of the upper portion of the face below the forehead. Each
+of these cavities is formed like a pyramid with four sides, of which
+the apex penetrates backwards towards the cranial cavity, and of which
+the base, turned forwards, forms the orbital opening. This opening, or
+_orbital margin_, is of quadrilateral form with rounded angles (Fig.
+58), limited by an internal border (7) and an external border, both
+almost vertical, by a superior border (3) and an inferior border, both
+oblique, from above downwards and outwards.
+
+  [Illustration: FIG. 58.
+
+   THE BONY STRUCTURE OF THE FACE.--1, the frontal bone;--2,
+   the nasal eminence;--3, supra-orbital notch;--4, the optic
+   foramen;--5, the sphenoidal fissure;--6, the spheno-maxillary
+   fissure;--7, the lachrymal groove;--8, the partition and opening
+   of the nasal fossæ;--9, the infra-orbital foramen;--10, the
+   malar bone;--11, the symphysis of the jaw;--12, the mental
+   foramen;--13, the ramus of the lower jaw;--14, the parietal
+   bone;--15, the coronal suture;--16, the temporal bone;--17,
+   the temporo-parietal suture;--18, the great wing of the
+   sphenoid;--19, the origin of the temporal ridge;--20, the
+   zygomatic arch;--21, the mastoid process.]
+
+The superior border is formed by the supra-orbital arch of the
+frontal bone (3, Fig. 58) previously described, which presents the
+supra-orbital notch; the inferior border is formed by the _superior
+maxillary_ and _malar_ bones; a little below its centre is a hole,
+called the _infra-orbital_ foramen (9, Fig. 58), which is placed in
+the upper jaw almost in the same vertical line as the supra-orbital
+notch above the orbit (page 168). The internal border is formed by the
+junction of the internal angular process of the frontal bone with the
+ascending (nasal) process of the superior maxilla (Figs. 56 and 58).
+Behind the inferior part of this border is a deep groove, called the
+_naso-lachrymal groove_ (7, Fig. 58), for the accommodation of the
+lachrymal sac (for the tears), which is the commencement of a canal
+(_naso-lachrymal canal_) connecting the orbit with the corresponding
+nasal fossa, and serving to transmit the nasal duct. Finally, the
+external border is formed by the junction of the external angular
+process of the frontal with the superior process of the _malar bone_,
+or bone of the cheek (10, Fig. 58; 14 and 15, Fig. 56).
+
+The cavity of the orbit has for its walls the osseous plates belonging
+to the frontal (superior wall) and the several bones of the face we
+have previously mentioned when describing the orbital opening. We
+need not enter here into the description of these surfaces and of the
+several special bones which compose them. We shall only say that the
+internal wall is directed from before backwards, while the external
+wall is oblique, from behind forwards and from without inwards. We
+note, lastly, at the deepest part (towards the apex) of the cavity,
+three apertures, by which the orbit communicates with deeper cavities;
+first, a circular orifice called the _optic foramen_ (4, Fig. 58);
+then, on the outer side of these, two fissures directed outwards, one
+obliquely upwards (_sphenoidal fissure_, 5, Fig. 58), and the other
+obliquely downwards (_spheno-maxillary fissure_, 6, Fig. 58). The two
+first communicate with the cranial cavity; the last-named fissure leads
+into the spheno-maxillary fossa.
+
+The _orifice of the nasal fossæ_ (8, Fig. 58) is situated in the middle
+of the face below the level of the orbits. It is somewhat heart-shaped
+(with the base downwards); it is bounded below by the two superior
+maxillary bones which unite in the middle line and form the _anterior
+nasal spine_, upon the sides by the same bones, and above by the two
+small _nasal_ bones (Fig. 56, page 165) wedged in on each side of the
+middle line between the nasal processes of the maxillary bones, and
+articulating above with the nasal notch of the frontal bone.
+
+Below, and to the outer side of each orbit, is the prominence of the
+cheek formed by the _malar bone_ (10, Fig. 58). This bone is formed
+like a star with four rays. The _superior_ or _orbital process_ (15,
+Fig. 56) joins the external angular process of the frontal bone; the
+_anterior process_ (17, Fig. 56) forms with the superior maxillary
+the inferior boundary of the orbit; the _posterior_ or _zygomatic
+process_ (16, Fig. 56) is directed backwards to form by its union with
+the zygomatic process of the temporal bone, the _zygomatic arch_; the
+_inferior_ angle is reduced to a prominent margin which joins with the
+body of the bone to form the _prominence of the cheek_. This prominence
+is due to the projection of a _malar process_ of the upper jaw on which
+the malar bone is fitted.
+
+There remain now only two bones to examine on the skeleton of the
+face--namely, the two bones which bound the cavity of the mouth and
+support the teeth: these are the superior and inferior maxillary or
+jawbones. The _superior maxillary bone_ (18, Fig. 56) has been in a
+great measure described already in relation to the orbital and nasal
+openings. The following points remain to be noticed: 1. The external
+surface is divided by a ridge descending from the malar process, into
+two surfaces--one outer, belonging to the zygomatic fossa, and the
+other anterior, appearing on the face. The facial surface is again
+subdivided into two smaller fossæ--the _canine fossa_, in which occurs
+the infra-orbital foramen, and the _incisive fossa_, above the incisor
+teeth--by a ridge (the _canine ridge_) which is formed by the prominent
+fang of the canine tooth. 2. The inferior or _alveolar_ border presents
+a series of cavities for the lodgment of the roots of the upper
+teeth. The presence of these cavities is marked on the surface of the
+alveolar border by a series of prominences separated by depressions
+corresponding to the partitions between the alveoli.
+
+  [Illustration: FIG. 59.
+
+   THE INFERIOR MAXILLARY BONE (side view).--1, the body of the
+   inferior maxillary bone and its external oblique line;--2,
+   the ramus;--3, the symphysis of the chin;--4, the mental
+   foramen;--8, the angle of the jaw;--10, coronoid process;--11,
+   the condyle;--12, sigmoid notch;--I, incisor teeth;--_c_, canine
+   tooth;--_b_, bicuspid;--_m_, molar teeth.]
+
+The _inferior maxillary bone_ or _mandible_ (Fig. 59) requires more
+detailed consideration than the other bones of the face, as it takes so
+direct a share in the surface form that we may say that all the details
+of its shape are marked in the configuration of the chin and lower
+parts of the cheeks. It is originally composed of two distinct halves,
+one right and one left, which are joined together in early life in the
+middle line of the chin to form the symphysis of the chin, or _mental
+process_ (11, Fig. 58). It is sufficient to describe one of these
+halves as we see it in a side view of the skull (Fig. 56).
+
+We see that each half is formed of two strong osseous plates joined
+together at an angle more or less approaching a right angle, of which
+the prominence directed downwards and backwards is called the _angle
+of the jaw_. The horizontal portion of the bone is called the _body_;
+the vertical portion is the _ramus_.
+
+The _ramus_ consists of a flat external surface, which is continued
+below into the body of the bone (2, Fig. 59). Its posterior border is
+thick, and is continued downwards to the angle of the jaw. The anterior
+border, which is thinner, is grooved, and terminates by joining below
+the upper alveolar border of the body of the bone. The borders of
+the groove join the oblique lines on the surfaces of the body of the
+bone. The superior border is divided by a deep notch (_sigmoid notch_,
+12, Fig. 59) into two very prominent parts. The posterior prominence
+is thick, and forms the neck, surmounted by the articular head, or
+_condyle_, of the jaw (11, Fig. 59), for articulation with the temporal
+bone; the anterior prominence is in the form of a triangular plate,
+and bears the name of the _coronoid process_ (10, Fig. 59); it gives
+insertion to the temporal and masseter muscles.
+
+The _body_ of the lower jaw extends from the angle to the _symphysis_
+of the chin (3, Fig. 59); it has an external surface marked by an
+oblique line, above which is an orifice (12, Fig. 58; and 4, Fig. 59)
+called the _mental foramen_, placed in the same vertical line as the
+supra-orbital notch and the infra-orbital foramen. It is situated about
+the level of the second premolar tooth. The inferior border of the bone
+is thick and rounded; its superior _alveolar_ border presents sockets
+for the teeth, and externally a series of prominences and depressions
+corresponding to the alveoli and the intervals between them.
+
+The character of the lower jaw changes with age; in the infant,
+the angle is very obtuse and but slightly prominent: in the adult
+it becomes almost a right angle: in the aged the form of the jaw is
+changed by the loss of the teeth and by the absorption of the alveolar
+border, causing a diminution of height in the body of the bone. In
+order, therefore, to bring the two jaws in contact with one another,
+the lower jaw requires to move strongly forwards and upwards, whence
+occurs a characteristic prominence of the chin in the aged, which seems
+to project upwards and forwards to meet the prominence of the nose.
+
+The teeth of the adult are altogether thirty-two in number--eight in
+each lateral half of each jaw. Each tooth is composed of a part fixed
+in the alveolar cavity called the _root_, and a free part called the
+_crown_. The form of the crown permits the division of the teeth into
+four distinct classes, which in each half of the jaw are arranged in
+the following manner, beginning from the median line:--Two _incisors_
+(I, Fig. 59), one _canine_ (_c_, Fig. 59), two _premolars_, or
+_bicuspids_ (_b_, Fig. 59), and three _molars_ (_m_, Fig. 59)--total,
+eight. Situated at the most external and posterior portion of the
+dental arch, the premolar and molar teeth are hidden by the cheeks, and
+we need only mention that they are characterised by a crown formed of
+numerous tubercles (two for the premolars, four or five for the molar
+teeth). On the other hand, the canine and incisor teeth are easily seen
+when the lips are separated. The _canine_ teeth are characterised by a
+conical crown with a sharp extremity, which is very large and prominent
+in the carnivora--_e.g._, in the dog (whence the name of canines).
+The _incisors_ present a crown flattened from before backwards, and
+rectangular in form (square). Their relative size is so constant that
+it should be stated here. The two largest are the median incisors of
+the upper jaw; next in order come the lateral incisors of the upper
+jaw, then the lower lateral, and finally the lower median incisors,
+which are the smallest. The lower incisors, besides being smaller, are
+characterised by their chisel-like cutting edge, which is bevelled at
+the expense of the outer surface.
+
+The articulation of the lower jaw with the skull, or _temporo-maxillary
+articulation_, is formed by the articulation of the condyle of the jaw
+(11, Fig. 59; and 29, Fig. 56) with the glenoid cavity of the temporal
+bone--a cavity placed in front of the external auditory meatus, and
+behind the _articular eminence_--the transverse root of the zygomatic
+process (page 169). This _glenoid cavity_, together with the articular
+eminence, is lined with cartilage, and is separated from the condyle
+of the jaw by an inter-articular fibro-cartilage. These structures are
+enclosed in a fibrous capsule which surrounds the articulation, and is
+strengthened on the outer side by a stout external lateral ligament,
+attached obliquely from a tubercle at the root of the zygoma downwards
+and backwards to the outer side of the condyle of the jaw. Therefore,
+when the jaw is depressed by a movement of rotation of the mandibular
+condyle upon its axis, this external lateral ligament is made tense,
+and draws the condyle forward, causing it to leave the glenoid cavity
+and come in contact with the articular eminence. Thus, when the mouth
+is widely opened (the lower jaw being greatly depressed) there is
+a displacement of the condyle of the jaw forwards, which is easily
+seen in thin subjects, and which should be noted here with its own
+particular mechanism.
+
+The face, as a whole, presents a special interest when we compare its
+configuration with that of the cranium, in various individuals and
+races. In general, the more prominent the skeleton of the face the less
+the cranium (the forehead) is developed. This was the idea of Camper, a
+Dutch anatomist and artist, about the middle of the eighteenth century.
+
+  [Illustration: FIG. 60.
+
+   THE MEASUREMENT OF THE FACIAL ANGLE (goniometer applied to a
+   skull).--1, the inferior horizontal plane of the goniometer;--2,
+   movable piece with a pin introduced into the auditory
+   meatus;--4, graduated circle;--5, the oblique plane attached
+   below by a hinge to the horizontal;--6, the rack for placing the
+   bar (7) on the prominent part of the forehead.]
+
+  [Illustration: FIG. 61.
+
+   THE FACIAL ANGLE OF A SKULL OF THE CAUCASIAN RACE (after
+   Camper).--_a b_ and _c d_, the lines which mark this angle
+   (see the text);--1, the auditory meatus;--2, anterior nasal
+   spine;--3, the most prominent part of the forehead.]
+
+Camper proposed to measure the relative proportions of the cranium and
+face by the angle which the plane of the profile of the face makes with
+that of the base of the skull. This facial angle has since been the
+subject of much study on the part of anatomists and anthropologists,
+who have modified and perfected the process of measurement. It will be
+sufficient here to show what Camper’s idea was, and that, apart from
+anatomical considerations, he designed to furnish artists with a means
+of giving character to the different physiognomies of men and animals.
+This angle is determined by two planes (upon a head seen in profile, by
+two lines): one plane, which we may call horizontal, proceeds from the
+external auditory meatus to the anterior nasal spine, and corresponds
+to the inferior border of the orifice of the nasal fossa (1, Fig. 60;
+and _a_, _b_, Fig. 61); the other, directed obliquely upwards and
+backwards, is at a tangent below to the prominence of the incisor
+teeth, and above to the most prominent part of the forehead (_c_,
+_d_, Fig. 61). Fig. 60 gives an idea of the apparatus with which we
+measure the facial angle at the present day. It represents the facial
+goniometer of Jacquart. The mode of measurement here differs from that
+employed by Camper, in that the inferior or horizontal plane passes
+forward not by the nasal spine, but by the prominence of the incisor
+teeth.
+
+Figures 61 and 62, which are reproduced from those of Camper, show on
+the one hand that while the facial angle is never equal to a right
+angle, it approaches to it in the best types of the white race.
+
+  [Illustration: FIG. 62.
+
+   THE FACIAL ANGLE OF A NEGRO (after Camper). The figures are the
+   same as in the preceding.]
+
+The ancients sought by an exaggeration to idealise the profile of the
+human face, and by increasing the fulness of the forehead they have
+given to heads of gods and heroes a facial angle as large as ninety
+degrees (Fig. 63). These figures show, also, the decrease of the facial
+angle in proportion as we pass from the white to the yellow and black
+races:--“The angle which the facial line or characteristic line of the
+visage makes,” said Camper, “varies from seventy to eighty degrees in
+the human species. All who raise it higher disobey the rules of art
+(from imitation of the antique); all who bring it lower fall into the
+likeness of the monkeys. If I cause the facial line to fall in front
+I have an antique head; if I incline it backwards I have the head of
+a negro; if I cause it to incline still further I have the head of a
+monkey; inclined still more, I have that of a dog; and, lastly, that of
+a goose.”[6] The figures which explain these ideas are as follows:--The
+facial angle of Camper averages 80 degrees in the Caucasian race; 75
+degrees in the yellow, or Mongol; 60 to 70 degrees in the Negro; 31
+degrees in the great monkeys (gorilla); lastly, 25 degrees in the head
+of a Newfoundland dog.
+
+  [Illustration: FIG. 63.
+
+   THE FACIAL ANGLE OF AN ANTIQUE HEAD (Apollo
+   Belvedere)--(Camper).]
+
+       *       *       *       *       *
+
+In our study of the various segments of the limbs we have seen that
+some of them have been chosen, in different systems of measurement, to
+serve as a common measure for these limbs, and for the entire body.
+Thus we have spoken of the canons which respectively take as a unit
+the _hand_ (contained about ten times in the height of the body), the
+_foot_ (contained a little more than six times in the total height),
+the _middle finger_ (contained nineteen times), &c., &c. It is true,
+also, that the head--_i.e._, the vertical distance from its summit to
+the base of the chin--may be taken also as a common measure. This was
+done long ago. Vitruvius, speaking of the proportions of the human
+body, states that the height of the head should be the eighth part of
+the whole body. Leonardo da Vinci, Albert Dürer, and J. Cousin have
+followed the rule of the Latin author; and the law which makes the
+head the eighth of the total height has for a long time past become
+classic in all the schools. The choice of the head as a unit seems
+sufficiently justified by the two facts that, on the one hand, in every
+representation of the human body the head is always visible, and forms
+a part distinct from the rest of the body, and that, admitting that
+it makes the eighth part of the height, this number is particularly
+convenient, not being too great; and, on the other hand, it is
+divisible by two. In this respect it offers, for example, a great
+advantage over that of nineteen, which represents the proportion of the
+middle finger to the height.
+
+  [Illustration: FIG. 64.
+
+  THE FACIAL ANGLE OF A MONKEY.
+
+  (Camper.)]
+
+Gerdy, who has adopted the law of eight heads, divides the height of
+the body in the following way: the first division comprises the head
+itself; the second extends from the chin to the level of the nipples;
+the third from the nipples to the umbilicus; the fourth from the
+umbilicus to the symphysis pubis; the fifth from the pubis to the
+middle of the thigh; the sixth from the thigh to the knee; the seventh
+from the knee to the middle of the leg; and, lastly, the eighth, from
+the middle of the leg to the sole of the foot (Fig. 65).
+
+  [Illustration: FIG. 65.
+
+   OUTLINE OF THE HUMAN BODY (and proportions).]
+
+The face itself can further be subdivided into subordinate parts. The
+classical method of subdivision is to say that the head is the length
+of four noses: one from the top of the head to the top of the forehead
+(hair), one each for the forehead and nose, and one for the part below
+the nose. This is generally, however, incorrect. It is better to divide
+the face into two portions across the equators of the eyeballs; and
+subdivide the lower half into two, for the greater part of the nose
+above, and the lips, mouth, and chin below.
+
+Now, if we submit to experiment the system of the law of eight heads,
+we see that it is accurate only in subjects of great height--for those
+who attain seventy-four inches and over; below seventy-two inches the
+subjects do not measure more than seven and a half, or only seven
+times the height of their head. In fact, the height of the head is a
+quantity which varies very little according to the subject; it is on
+the average, as an absolute measurement, from 8⅔ to 9 inches, and the
+variations which this value may present do not range below 8¼ inches
+or above 9 inches. A subject who measures eight heads is very tall (9
+× 8 = 72, equal, or superior, to 72 inches); and a subject who only
+measures seven heads is of short stature (8⅔ × 7 = 61, equal, or more
+frequently exceeding, 61 inches).
+
+This difference in the number of heads that the body measures in
+relation to absolute height seems more interesting than the narrow
+theory which would assign strictly the length of eight heads to each
+human figure. This absolute system does not agree with that which
+observation proves correct. Besides, it would be an error to suppose
+that the ancient sculptors would be slaves to such a system of
+proportions, since we find in their works precisely the same variations
+that we do in nature. The _Gladiator_, it is true, measures eight
+heads; but at the first glance at this _chef d’œuvre_ we have the
+impression of a subject of great stature--of a man tall and spare. The
+_Apollo_ and the _Laocoon_ measure only 7⅔, and the _Antinous_ only 7½
+heads.
+
+The variations in height are almost solely caused by the greater or
+lesser length of the lower limbs. Whether the subject be tall or short,
+the trunk (with the head and neck) varies comparatively little; but the
+thighs and legs make the differences of length. Regarding the diversity
+that we meet with in this question, we see that Gerdy himself has not
+been exact in indicating the points where the lengths of the head begin
+and terminate which divide the lower limb, the middle of the thigh, and
+the lower part of the knee; those points are badly defined, especially
+as he does not indicate precisely the superior extremity of the thigh.
+But the looseness and contradiction becomes still more evident when
+we come to seek, according to the various authors, the intersection
+between the fourth and fifth head; that is to say, the middle of the
+body. Without speaking of the singular inconsistency of Vitruvius, who
+places the middle of the body at the level of the navel, we will note
+only this fact, that for the passage from the fourth head to the fifth
+some take the pubis, others some other point.
+
+The centre of height falls lower as the stature of the subject
+is increased. In subjects of small stature the centre of height
+corresponds to the symphysis of the pubis; for those of middle height
+and over, it falls about half an inch below the pubis. But it may be
+situated at a still lower level, and the artists of antiquity have
+frequently placed it much lower. In fact, as Professor Sappey says, the
+taller the stature, the more the centre of the body tends to fall below
+the symphysis, and the figures of heroes and gods are of tall stature.
+
+We will say, then, in conclusion: 1, that the head, compared with the
+height, is shorter as the height increases; 2, that to produce a human
+figure, the absolute dimensions of which would give the impression of
+a subject of short stature, it would be necessary to give it about 7½
+heads, and to cause the centre of the body to fall on the symphysis
+pubis; while to produce a figure to give the impression of tall stature
+it would be necessary to give it 8 heads, and to place the centre of
+the body more or less below the symphysis pubis.
+
+
+
+
+                            =Second Part.=
+
+
+
+
+                        MUSCLES AND MOVEMENTS.
+
+
+
+
+                             CHAPTER XVI.
+
+                    PECTORAL AND ABDOMINAL MUSCLES.
+
+   Of _muscles_ in general.--_Muscular contraction_: changes
+   of form; movements produced. Composition of muscles; fleshy
+   belly and tendon; aponeurosis. Nomenclature of muscles, their
+   classification into long, broad, and short muscles; their
+   arrangement: superficial and deep. Muscles of the trunk,
+   anterior region.--_Great pectoral muscle_, its relation to the
+   armpit, its action.--_The lesser pectoral._--The _breast_ and
+   _nipple_.--The _external oblique muscle of the abdomen_, its
+   fleshy part, its abdominal aponeurosis; _linea alba_.--Groove
+   and space bounded by the prominence of the _external oblique_
+   and _rectus_.--_Internal oblique_ and _transversalis_
+   muscles.--_Rectus abdominis_ muscle, its aponeurotic sheath,
+   its aponeurotic intersections.--_Linea semilunaris_; _lineæ
+   transversæ_.
+
+
+The form of the body is produced largely by the muscles. Each
+muscle is formed of a peculiar tissue called _muscular tissue_ or
+_muscular fibre_, which has the property of changing its form and of
+_contracting_ under the influence of nervous action, in most cases
+controlled by the will. For example, in contracting the biceps muscle
+on the front of the arm, we see that this muscle, which in a state of
+repose is fusiform and long, becomes in action (in contraction) short,
+thick, and rounded; and as it is attached below to one of the bones
+of the forearm, it draws the anterior surface of the forearm towards
+the anterior surface of the upper arm and produces flexion of the
+elbow-joint. This simple experiment, which is easy to repeat at any
+moment, gives a clear idea of the part which muscles play in the animal
+economy, and of the part that they take in producing the external form;
+for it shows that they are the _active agents_ of movements in which
+the bones are the _passive levers_, and, at the same time, that a
+muscle in action presents a very different shape from that which it has
+in a state of repose, a change which may be stated in a more general
+manner by saying that in action a muscle becomes shorter, thicker, and
+more prominent.
+
+  [Illustration: FIG. 66.
+
+  DIAGRAM OF A CONTRACTED MUSCLE (Biceps).]
+
+In general, besides their _fleshy mass_, the only part which contracts
+and changes its form, the muscles have extremities more or less slender
+called _tendons_, formed of a white fibrous tissue, which are, as it
+were, actual cords by which the muscle is attached to the bones; during
+the contraction of muscle these tendons do not change in form, but, as
+with all tight cords when in a state of tension, they start up, and
+become more visible and clearly marked beneath the skin (Fig. 66).
+
+Each muscle is enveloped by a fibrous membrane called its
+_aponeurosis_, which frequently takes the place of a tendon, if the
+muscle is broad and thin, so that in these cases the attachment of the
+muscle, instead of being rounded in the form of a cord, is flattened in
+the form of a membrane, and the term aponeurosis is at times applied
+to these membranous tendons. Membranous tendons in the contraction of
+a muscle give rise to depressions on the surface of the body in the
+regions where they occur superficially.
+
+The muscles are variously named according to various ideas; sometimes
+from the region they occupy (_pectoral_, _gluteal_, _anterior brachial
+muscles_, _&c._) or from the direction of their fibres (_oblique of the
+abdomen_), or from their dimensions (_gluteus maximus, gluteus medius,
+and peroneus longus, &c._), or again from their form (_trapezius,
+rhomboid, serratus_), or from their structure (_semi-membranosus,
+semi-tendinosus_). Another mode of nomenclature, which Chaussier
+attempted to make general, forms the name of a muscle by the
+association of the names of the bones to which it is attached; in this
+way we get the _sterno-cleido-mastoid muscle_, and most of the muscles
+of the neck. This nomenclature, however, cannot be easily applied to
+all muscles, for it would make some names of an inconvenient length,
+owing to the complexity of the bony attachments.
+
+Before we terminate this rapid sketch it may be useful, with regard
+to plastic anatomy, to point out how the various muscles are classed,
+according to their form and situation. 1st. With regard to their form
+we distinguish the muscles as _long_, _broad_, and _short_; the _long
+muscles_, consisting in general of a fleshy belly fusiform in shape,
+and with cord-like tendons, are principally distributed among the great
+segments of the limbs (arm, forearm, thigh, leg); the _broad muscles_,
+with their fibres arranged in broad and thin layers, and with tendons
+membranous and aponeurotic, are almost exclusively found in the trunk
+(pectorals, trapezius, latissimus dorsi, &c.); lastly, the _short
+muscles_, frequently without tendons, and inserted directly into the
+bone, are found principally at the extremities of the limbs (hand and
+foot) and in the face.
+
+2nd. With regard to their situation we distinguish the muscles as
+_superficial_ and _deep_. The _superficial muscles_ (Fig. 67) are those
+which are entirely visible when the subject is stripped of its skin,
+and of which, accordingly, the fleshy bellies and tendons are marked in
+their principal details on the external form. These superficial muscles
+should be carefully studied here with regard to their insertions,
+forms, and actions. The _deep muscles_, situated beneath the preceding,
+form fleshy masses, which are shown externally by the manner in which
+they fill up the external depressions of the skeleton, and raise up the
+superficial muscles. It is enough for the artist to know the general
+indications of these muscular masses, without studying the insertions
+and forms of each of the muscles composing any given mass.
+
+
+                         MUSCLES OF THE TRUNK.
+
+Under this title we will now study the anterior muscles of the trunk
+(_pectoral and abdominal_), and the muscles of the back and the
+posterior surface of the neck (_trapezius_ and _latissimus
+dorsi_). The study of the muscle which covers the lateral wall of
+the chest (_serratus magnus_) will be taken after that of the
+muscles of the shoulder and armpit.
+
+  [Illustration: FIG. 67.
+
+   GENERAL VIEW OF THE SUPERFICIAL MUSCLE (the _Gladiator_ of
+   Agasias with the skin removed. Compare with Figure 4, page 24).]
+
+_Great pectoral muscle._--The great pectoral muscle (_pectoralis
+major_) forms a large fleshy mass (1, Fig. 68) which covers the
+anterior surface of the thorax, on each side of the middle line of the
+sternum, and extends outwards as far as the upper part of the arm. This
+muscle is attached (1st) to the inner half of the anterior border of
+the clavicle (2, Fig. 68); (2nd), to the whole extent of the anterior
+surface of the sternum (3, Fig. 68); and (3rd), to the aponeurosis
+of the external oblique muscle of the abdomen. It arises, also, more
+deeply from the cartilages of the true ribs (except the first) (9,
+9, 9, Fig. 68). From these thoracic origins the muscular fibres are
+directed towards the arm; the upper fibres pass obliquely from above
+downwards and outwards; the middle fibres pass transversely outwards,
+and the inferior, obliquely from below upwards. Towards the insertion
+of the muscle these different parts cross over each other in a twisted
+form, so that the upper (clavicular) fibres are placed in front of
+the inferior (sternal) fibres (7, Fig. 68), which correspond to the
+anterior margin of the armpit. The muscle is inserted into the outer
+lip of the bicipital groove of the humerus, the clavicular fibres,
+known as the _portio attollens_, being inserted lower down the arm than
+the external fibres (_portio deprimens_). The former fibres raise the
+arm upwards, the latter draw it downwards in relation to the trunk.
+
+  [Illustration: FIG. 68.
+
+   THE MUSCLES OF THE ANTERIOR SURFACE OF THE THORAX (to the right
+   the superficial muscles; to the left the deep muscles).--1,
+   the great pectoral muscle;--2, its clavicular fibres;--3,
+   its costo-sternal fibres;--4, 5, 6, its origin from the
+   aponeurosis of the abdomen;--7, its external portion formed
+   by the superposition of the preceding fibres (9, bundles
+   of fibres arising from the cartilages of the ribs; 10, the
+   pectoralis minor);--11, the subclavius;--12, the deltoid;--14,
+   the digitations of the serratus magnus;--15, the digitations of
+   the external oblique of the abdomen;--16, anterior border of
+   the latissimus dorsi, and (17) tendon of the same;--18, teres
+   major muscle;--19, the subscapularis;--20, the long head of the
+   triceps brachialis; 21, the humeral extremity of the deltoid;
+   22, 22, the sterno-cleido-mastoid;--23, the sterno-hyoid;--24,
+   the trapezius muscle.]
+
+When the arm is hanging beside the trunk the great pectoral muscle
+presents a four-sided square, in which we can distinguish four borders:
+one supero-external (in contact with the anterior border of the
+deltoid, 12, Fig. 68), another superior, in the line of the clavicle;
+the third, internal or sternal, curved with its convexity inwards; and
+the fourth, infero-external or axillary (forming the anterior boundary
+of the armpit). But when the arm is horizontal, and especially when it
+is raised above the horizontal (Fig. 70), the figure of the muscle is
+represented by a triangle with the base inwards, as the clavicular and
+supero-external borders then come into line with one another.
+
+The action of the great pectoral muscle is essentially to draw the
+arm to the trunk; its shape becomes prominent when we carry the arms
+forward and bring them near each other, as in the attitude of prayer.
+It also becomes well marked in climbing, for then the muscle takes its
+fixed point at the humerus and draws the trunk towards it. Acting in
+a similar manner upon the thorax, with the humerus as a fixed point,
+this muscle elevates the ribs, and consequently expands the thorax in
+respiration. Thus we see that the muscle contracts when the inspiratory
+muscular powers are brought into play as in movements like struggling,
+anguish, or agony.
+
+  [Illustration: FIG. 69.
+
+  OUTLINE OF THE FEMALE BREAST.]
+
+_The breast and nipple._--On the surface of the great pectoral muscle
+is placed the breast in the female. In the male only the nipple and
+surrounding _areola_ are found, usually occupying a position at the
+level of the space between the fourth and fifth ribs on each side. The
+form of the breast varies in the female with age. In a young woman it
+is normally round and firm, with its lower aspect more rounded than its
+upper surface, which is slightly flatter (in the erect position) (Fig.
+69).
+
+  [Illustration: FIG. 70.
+
+   THE MUSCLES OF THE ANTERIOR WALL OF THE TRUNK.--1, 2, 3,
+   the great pectoral;--4, 4, the external oblique of the
+   abdomen;--5, 5, the serratus magnus;--6, 6, the anterior border
+   of the latissimus dorsi;--7, 8, the inferior portion of the
+   sternum;--9, the aponeurosis of the external oblique;--10,
+   linea alba;--11, umbilicus;--12, 12, 12, the tendinous
+   intersections of the rectus abdominis;--13, the inguinal
+   ring;--14, the pyramidalis of the abdomen;--15, the external
+   border of the rectus abdominis;--16, the sterno-hyoid;--17,
+   the omo-hyoid;--18, sterno-cleido-mastoid;--19, the
+   trapezius;--20, the deltoid;--21, the biceps brachialis;--22,
+   the pectineus;--23, the sartorius;--24, the rectus femoris;--25,
+   the tensor of the _fascia lata_;--26, the adductors.]
+
+The great pectoral muscle conceals under its middle third a smaller
+muscle, the _lesser pectoral_ (10, Fig. 68), which, arising from the
+third, fourth, and fifth ribs, is directed upwards and outwards, to
+be attached to the coracoid process of the scapula. This muscle serves
+to move the scapula by drawing its upper part downwards and forwards.
+Its outer border becomes obvious when the arm is raised above the head,
+along the axillary border of the great pectoral muscle.
+
+_The external oblique muscle of the abdomen._--The external oblique
+muscle of the abdomen (Figs. 68 and 70) forms a large sheet half
+fleshy, half aponeurotic, which covers the lateral and anterior
+surfaces of the abdomen. The fleshy portion, which forms the outer half
+of the muscle, is attached to the external surfaces of the lower eight
+ribs, from which it arises by angular slips or digitations, interlacing
+with those of the serratus magnus and latissimus dorsi muscles (15,
+Fig. 68, and Fig. 74). From these costal origins the fibres are carried
+forwards and downwards; the posterior fibres pass vertically downwards
+to be attached to the iliac crest (Fig. 74); the others are directed
+obliquely downwards and forwards, to give origin to a broad membranous
+tendon (9, Fig. 70) called the _aponeurosis of the external oblique
+muscle_. The fibres of this aponeurosis, continuing in the original
+direction of the muscular fibres, pass in front of the rectus muscle
+of the abdomen (12 and 15, Fig. 70), where, joining the subjacent
+aponeuroses of the internal oblique and transversalis muscles, and
+interlacing with the aponeurotic fibres of the opposite side, it
+forms a long median raphé, called the _linea alba of the abdomen_,
+proceeding from the xiphoid cartilage to the symphysis pubis (10, Fig.
+70).
+
+It is important, with regard to external form, to define the direction
+of the line at which the aponeurotic fibres of the external oblique
+succeed to the fleshy fibres (Fig. 70). This line descends at first
+vertically from its origin at the inferior angle of the great pectoral
+muscle, but its lower part inclines abruptly outwards (4, Fig. 70),
+towards the anterior superior iliac spine, describing a curve with
+its convexity downwards and inwards. This line marks the prominence
+of the anterior or internal border of the muscular fibres; and as,
+on the other hand, the rectus abdominis muscle forms, by its outer
+border, another curved line (_linea semilunaris_), which is at first
+vertical but inclines inwards below (15, Fig. 70), it follows that this
+part of the anterior surface of the abdomen is traversed by a narrow
+vertical groove which opens out below into a large triangular space.
+This triangular space, bounded above and on the outer side by the
+external oblique muscle, and on the inner side by the semi-lunar line
+of the rectus, is limited below by the fold of the groin, or _Poupart’s
+ligament_, the line at which the aponeurosis of the external oblique
+becomes attached to the fascia lata of the thigh (page 111). In the
+male this part of the aponeurosis of the external oblique is perforated
+just above the inner end of Poupart’s ligament (13, Fig. 70) by the
+spermatic cord, which passes obliquely downwards and inwards in the
+inner part of the groin.
+
+  [Illustration: FIG. 71.
+
+   THE MUSCLES OF THE ABDOMEN (the superficial on the right
+   side, the deep on the left).--1, the external oblique;--2, 2,
+   the serratus magnus;--3, 3, the aponeurosis of the external
+   oblique;--4, the umbilicus;--5, 6, the linea alba;--7, the
+   crural arch or Poupart’s ligament;--8, the inguinal ring;--9,
+   pectoralis major;--10, latissimus dorsi;--11, 11, the rectus
+   abdominis;--13, the anterior portion of its sheath;--14, the
+   pyramidalis;--15, 15, the internal oblique of the abdomen;--16,
+   the inferior portion of the aponeurosis of the external oblique
+   turned downwards;--18, the upper part of the thigh covered by
+   its aponeurotic envelope;--19, a section of the external oblique
+   of the abdomen.]
+
+The external oblique muscle draws the ribs downwards and forwards. If
+the two muscles of that name (that of the right and that of the left
+side) contract at the same time they bend the body forward; but when
+one muscle only--_e.g._, that of the right side--contracts it imparts
+to the trunk a movement of rotation to the left or opposite side.
+Generally speaking, whenever we make any great effort the oblique
+muscles of the abdomen contract, and their prominences, especially the
+costal digitations and the anterior borders of the muscles, become
+clearly marked.
+
+  [Illustration: FIG. 72.
+
+   THE MUSCLES OF THE BACK.--1, trapezius;--2, its vertebral
+   origin;--3, acromion process;--4, Latissimus dorsi;--5,
+   deltoid;--6, infraspinatus;--7, obliquus externus;--8, gluteus
+   medius;--9, gluteus maximus;--10, levator anguli scapulæ;--11,
+   rhomboid minor;--12, rhomboid major;--13, splenius;--14,
+   transversalis cervicis;--15, vertebral aponeurosis;--16,
+   serratus posticus inferior;--17, supraspinatus;--18,
+   infraspinatus;--19, teres minor;--20, teres major;--21,
+   triceps;--22, serratus magnus;--23, obliquus internus.]
+
+The external oblique muscle covers two other muscular layers, which
+are, passing from without inwards, the _internal oblique_ (15, Fig.
+71) and _transversalis_ muscles. The internal oblique muscle is formed
+by fibres which arise from the fascia of the loin, the crest of the
+ilium, and Poupart’s ligament. They radiate forwards and for the most
+part upwards (Fig. 71) to become attached, the superior fibres to the
+lower six ribs, while the middle and inferior fibres are continued in
+front as an aponeurosis, or broad flat tendon. The aponeurosis soon
+becomes united, partly, with that of the external oblique and that
+of the transversalis beneath. This aponeurosis splits to enclose the
+rectus abdominis muscle and constitute the _sheath of the rectus_. The
+_transversalis_ muscle is formed by fibres directed horizontally, and
+it terminates in front in an aponeurosis which passes for the most part
+behind the _rectus abdominis_, to blend with the aponeurosis of the
+internal oblique muscle and assist in the formation of the sheath of
+the rectus abdominis.
+
+The _rectus abdominis_ (11, 11, Fig. 71).--This muscle forms a long,
+broad, fleshy band on each side of the _linea alba_, which occupies
+the middle line of the abdomen. Extending from the epigastric pit to
+the pubis, it is attached above at its base, which is its widest part,
+to the cartilages of the filth, sixth, and seventh ribs, and to the
+ensiform cartilage, and below, at its apex, or narrowest part, by a
+double tendon to the crest and spine of the pubis. The muscle presents,
+with regard to form, several remarkable peculiarities. 1st. It is
+enclosed in a fibrous sheath, formed in front by the aponeuroses of
+the external and internal oblique muscles (16, Fig. 71), and behind
+by the aponeuroses of the internal oblique and transversalis; so
+that in the subject stripped of its skin its shape is half concealed
+by the aponeurotic lamina which passes in front of it (Fig. 70 and
+the right half of Fig. 71). 2nd. It is not formed of fleshy fibres
+proceeding without interruption from the costal cartilages to the
+pubis, but it is crossed by aponeurotic intersections (Figs. 70, 71),
+the _lineæ transversæ_, at the level of which the fleshy fibres are
+replaced by short tendinous fibres. These aponeurotic intersections
+are usually three in number, the most inferior being placed at the
+level of the umbilicus (4, Fig. 71), the other two higher up--one at
+the level of the ninth rib, the other at the level of the seventh.
+These intersections adhere to the anterior wall of the sheath of the
+muscle, and as the muscle is thinner at their level each line is marked
+on the surface by a transverse groove. 3rd. The portion of the muscle
+below the level of the umbilicus does not present any aponeurotic
+intersection, but it rapidly diminishes in breadth from the umbilicus
+to the pubis, so that the outer border of the muscle slopes from above
+downwards and inwards. To this arrangement is due the fact, upon which
+we have already dwelt (page 199), that the narrow groove bounded by the
+external oblique and the rectus muscles spreads out below the umbilicus
+into a broad, triangular surface, which is bounded below by the fold of
+the groin.
+
+The rectus muscle flexes the trunk; that is, it depresses the thorax
+and brings it nearer the pubis--a movement which it accomplishes by the
+flexion of the vertebral column.
+
+The lower part of the rectus muscle is covered by the _pyramidalis_
+muscle (14, Fig. 71), of which the contour does not show beneath the
+skin in the supra-pubic region, as the skin here is always padded by
+a cushion of fat. This pyramidalis muscle, which is only pointed out
+here in order that it may be remembered, forms on each side of the
+middle line a small fleshy triangle, of which the base is attached to
+the pubis, and the apex forms a short tendon which is inserted into the
+linea alba, the median fibrous raphé resulting from the interlacing
+of the aponeuroses of the oblique and transversalis muscles of the
+abdominal wall.
+
+
+
+
+                             CHAPTER XVII.
+
+                         MUSCLES OF THE BACK.
+
+   _Trapezius_, attachments and surface form.--_Latissimus
+   dorsi._--_Deep muscles_ visible in relation to the trapezius
+   and latissimus dorsi--1, lateral region of neck (_splenius_ and
+   _complexus_ muscles); 2, region of the scapula (_rhomboid_,
+   _infraspinatus_, _teres major_ and _teres minor_ muscles).--Deep
+   muscles which are wholly concealed: _erector spinæ_, etc.
+
+
+The most superficial muscles of the back are the trapezius and the
+latissimus dorsi. They form two broad muscular sheets which cover over
+the whole of the back and the posterior part of the neck, and extend
+also to the shoulder and arm.
+
+_Trapezius muscle._--The _trapezius_ muscle has the following
+attachments. Its origin is from the middle line of the back, from the
+inner third of the superior curved line of the occipital bone (13, Fig.
+73), the fibrous band of the _ligamentum nuchæ_ between the occipital
+protuberance and the spinous process of the seventh cervical vertebra,
+and from the spinous processes of the seventh cervical and of all the
+thoracic vertebræ. From these origins the muscular fibres are carried
+outward and converge towards the shoulder, the intermediate fibres
+passing transversely, the superior obliquely downwards (9, Fig. 74),
+and the inferior fibres obliquely upwards. The muscle is inserted into
+the shoulder girdle, to the superior border of the spine of the scapula
+(Fig. 73), the inner edge of the acromion process, and the outer third
+of the posterior border of the clavicle (19, Fig. 70; 7–13, Fig. 73).
+
+With regard to external form the trapezius muscle presents this
+remarkable fact, that in certain regions the muscular fibres are
+replaced by aponeurotic fibres or tendons, so that in these regions the
+muscle is thinner and in contraction shows slightly depressed surfaces.
+These regions are three in number: 1. At the lower part of the neck
+and the upper part of the back (10, Fig. 73), opposite the level of
+the seventh cervical spine, the fibres of origin of the muscle are
+aponeurotic, and form with those of the opposite side a lozenge-shaped
+or elliptical surface with its long diameter vertical, in the centre of
+which the spinous processes of the sixth and seventh cervical and first
+thoracic vertebræ form more or less well-marked projections. 2. At the
+lower part of the back, at the level of the last thoracic vertebræ,
+the fibres of origin of the trapezius are also aponeurotic, in a small
+triangular space; and in the living model, when the trapezius is
+strongly contracted, its lower angle seems hollowed out, because at
+that level the muscular fibres are wanting, and in consequence do not
+swell up when the muscle is in action. 3. At the level of the root of
+the spine of the scapula, the inferior fibres of the trapezius form
+at their insertion a small triangular aponeurosis which glides on the
+bone, and gives rise to a distinct depression at that spot during the
+contraction of the muscle.
+
+  [Illustration: FIG. 73.
+
+   THE SUPERFICIAL MUSCLES OF THE BACK.--1, The lumbo-sacral
+   aponeurosis;--2, the latissimus dorsi;--3, its iliac
+   fasciculus;--4, the space which separates it from the external
+   oblique;--5, the upper portion of the latissimus dorsi;--6, 6,
+   the teres major muscle;--7, the lower portion of the trapezius,
+   with its aponeurotic portion (8) on a level with the spine
+   of the scapula;--9, the central portion of the trapezius,
+   with its aponeurosis (10);--11, 12, 13, the upper portion of
+   the trapezius;--15, the occipito-frontalis muscle;--16, the
+   sterno-cleido-mastoid;--17, the splenius capitis;--18, the
+   deltoid;--19, the infraspinatus;--20, the teres minor;--21, 21,
+   the external head, and 22, 22, internal head of the triceps
+   brachialis;--23, the posterior portion of the external oblique
+   of the abdomen;--24, 24, the gluteus maximus.]
+
+_Action of the trapezius._--When the shoulder is strongly drawn
+backwards the whole of the trapezius contracts, and in this case it
+is the middle portion, of which the fibres are directed horizontally,
+which shows most prominently beneath the skin. More frequently,
+however, different parts of the muscle contract separately; thus the
+superior fibres act, either by taking the shoulder as a fixed point,
+and bending the head to the corresponding side (as when the face
+is slightly turned to the opposite side), or by taking their fixed
+point at the occipital and the cervical origin, and thus raising and
+supporting the scapula, as when a burden is carried on the shoulder.
+Under those circumstances the cervical border of the trapezius, that
+which proceeds from the occipital bone to the clavicle (Fig. 74),
+becomes prominent in a line nearly parallel to that of the outer border
+of the sterno-cleido-mastoid (26, Fig. 74); and between these two
+prominent lines appears a groove (the _posterior triangle_ of the
+neck), to which we will return in dealing with the deep muscles of this
+region. Lastly, if the inferior fibres of the trapezius contract alone,
+they draw the shoulder downwards, and thus we see them become prominent
+whenever the model causes a dragging with his upper limbs from above
+downward, _e.g._, in the case of a bell-ringer who pulls violently
+and with all his weight on a rope.
+
+The two trapezius muscles (right and left) form together (Fig. 73) a
+rhomboidal figure with its apex below, which resembles the contour of
+a monk’s hood. Hence the trapezius has been called by anatomists and
+artists the _cucullary muscle_ (_cucullus_, a hood).
+
+_Latissimus dorsi muscle_ (1, 2, 3, 5, Fig. 73).--This forms a large,
+somewhat triangular muscular sheet extending from the region of the
+loins to the upper part of the arm. It arises by means of a broad
+triangular aponeurosis (_vertebral aponeurosis_, 1, Fig. 73) from the
+spinous processes of the lower six thoracic vertebræ, from the spinous
+processes of the lumbar and sacral vertebræ and the posterior third
+of the crest of the ilium (3, Fig. 73); the muscular fibres converge
+from this origin towards the armpit, and the muscle obtains additional
+origins at its borders. At the outer border of the muscle, three or
+four fleshy bands join it which arise from the outer surfaces of the
+last three or four ribs by slips which interdigitate with the fibres
+of the external oblique muscle of the abdomen (4, 4, Fig. 74). At
+its upper border, as it crosses the inferior angle of the scapula,
+the muscle receives a narrow slip of origin from this part of the
+shoulder-blade. From these origins the muscular fibres are directed
+upwards and outwards, and converge so as to form a fleshy layer (5,
+Fig. 73) which, passing over the inferior angle of the scapula and
+along its axillary border, winds round the _teres major muscle_ (see
+later), and over the posterior wall of the armpit to reach the upper
+part of the shaft of the humerus, in which it is inserted by a broad
+tendon, attached to the floor of the bicipital groove of the humerus
+(page 61).
+
+This muscle acts first of all like the lower part of the trapezius,
+but with more energy. It, further, not only depresses the scapula, but
+also acts on the humerus. It is the contraction of the latissimus
+dorsi which enables us to bring the arm with force to the side,
+carrying the upper limb slightly backwards, so that if the contraction
+is carried very far the arms become crossed behind the back. Indeed,
+the latissimus dorsi may be called the swimmer’s or golfer’s muscle.
+It draws the humerus backwards behind the trunk, and at the same time
+rotates the arm-bone and the whole limb inwards. The prominence formed
+by the outer border of the latissimus dorsi during contraction (Fig.
+74) is principally shown when the muscle accomplishes a powerful
+effort, such as dragging, or pulling from above downwards, as in
+pulling on a rope hanging vertically, or in hanging by the arms from a
+horizontal bar. If in this situation--in the exercise of the trapeze,
+for example--the model raises himself, and brings the trunk near the
+bar, the latissimi dorsi muscles become very prominent, for then they
+take their fixed points at the arms, and act on the trunk by carrying
+it upwards and forwards.
+
+Among the numerous deep muscles of the back there are not any which are
+visible on the surface throughout their entire extent, but there are
+many which appear in part in the spaces which limit the borders of the
+trapezius, latissimus dorsi, and superficial muscles of the shoulder
+and neck. These spaces are three in number, one at the side of the
+neck, one at the level of the lower half of the scapula, and a third
+over the iliac crest.
+
+The _posterior triangle_ is the name given to the space on the
+lateral surface of the neck, bounded (Figs. 73 and 74) behind by the
+supero-anterior border of the trapezius, and in front by the posterior
+border of the sterno-cleido-mastoid. This space forms a long and
+superficial groove, extending from the occipital region to the middle
+of the clavicle. It has a lower part (25, Fig. 74), covered over by the
+_platysma myoides_ muscle of the neck (to which we will return later),
+and a superior part, in which parts of one or two powerful muscles of
+the neck are found. 1st. The muscular fibres which we see (17, Fig. 73)
+directed obliquely from below upwards and outwards towards the mastoid
+process belong to the _splenius capitis_ muscle, which arises from the
+spinous processes of the last cervical and upper four or five thoracic
+vertebræ, and ascends obliquely outwards to be attached to the mastoid
+process of the temporal bone beneath the sterno-cleido-mastoid (16,
+Fig. 73). 2nd. A small fleshy triangle, which may appear above the
+splenius, at the apex of the posterior triangle, corresponds to a part
+of a powerful muscle of the neck, called the _complexus_, which may or
+may not be completely concealed by the trapezius muscle. It is always
+responsible for the surface form of the neck, and, along with the other
+deep muscles, appears as a prominent ridge on each side of the groove
+formed by the edge of the ligamentum nuchæ.
+
+The space situated in the back at the level of the lower part of the
+scapula is triangular in form (Figs. 73 and 74). When the arm is
+hanging beside the trunk the borders of the space are seen to be as
+follows: Externally, the vertebral border of the scapula; above and
+internally, the lower edge of the trapezius; and below, the upper edge
+of the latissimus dorsi. In the floor of the space the greater rhomboid
+muscle is seen; while external to the triangle are the prominences
+of the muscles covering the lower part of the dorsal surface of the
+scapula, _the infraspinatus_, _teres minor_, and _teres major_ muscles.
+
+The _greater rhomboid muscle_ (rhomboideus major) arises from the
+spinous processes of the seventh cervical and upper four or five
+thoracic vertebræ; its fibres are directed obliquely downwards and
+outwards, to be inserted into the vertebral border of the scapula. It
+is only the lower fibres which become superficial, behind the vertebral
+border of the scapula.
+
+The _infraspinatus muscle_ (19, Fig. 73) rises from the infra-spinous
+fossa of the scapula. From this origin its fibres ascend and,
+converging beneath the deltoid (Fig. 74), are inserted by a short
+tendon into the great tuberosity of the humerus.
+
+The _teres minor muscle_ (20, Fig. 73) rises from the upper part of the
+thick border of the infra-spinous fossa on the axillary border of the
+scapula, and ascends along the edge of the infraspinatus and beneath
+the deltoid, to be inserted into the lowest of three facets on the
+great tuberosity of the humerus.
+
+The _teres major_ (6, Fig. 73, and 8, Fig. 74) arises from the lower
+part of the broad axillary border of the infra-spinous fossa; it
+extends upwards and outwards like the preceding muscles, but it soon
+leaves the teres minor (5, Fig. 75). Instead of remaining at the
+posterior part of the shoulder it passes beneath the deltoid, and
+accompanies the latissimus dorsi muscle (Figs. 17, 18; Fig. 68) to the
+front of the long head of the triceps, and is finally inserted into the
+inner lip of the bicipital groove of the humerus. The long head of the
+triceps is found, therefore, passing between the teres minor, behind,
+and the upper part of the teres major, in front (Fig. 73, between 20
+and 6).
+
+These muscles become more visible and prominent when the arm is raised
+and arrives at the horizontal position (see the right side of Fig.
+73). The space between the edge of the trapezius and the border of the
+scapular spine above, and the latissimus dorsi below, becomes much
+lengthened from within outwards, and the deltoid leaves uncovered
+a greater extent of the infraspinatus, teres major and teres minor
+muscles; at the same time the scapula, by the elevation of the arm
+(page 64), being moved so that its inferior angle is drawn away from
+the vertebral column, a greater part of the rhomboid muscle becomes
+apparent between the outer border of the trapezius and the upper border
+of the latissimus dorsi.
+
+Although the other deep muscles of the back are not visible on the
+subject stripped of its skin, we must not leave the region without
+giving a few of the names of the powerful fleshy masses which occupy
+the lumbar region, on each side of the spinous processes, and form
+two powerful muscular columns, causing a prominence beneath the
+aponeurosis of the latissimus dorsi (Fig. 73). This mass is formed by
+muscles in the loin which are closely blended together below, and
+constitute the _erector spinæ_. At the lower level of the thorax it
+separates into an external muscle called the _ilio-costalis_, which
+is attached by a series of tendons to the angles of the ribs, and an
+internal muscle called the _longissimus dorsi_, which, by a series of
+tendons, is attached to the ribs and to the transverse processes of the
+thoracic vertebræ. These muscles are continued through the upper part
+of the back and the neck by means of smaller slips which need not be
+particularised. The action of the erector spinæ and its several parts
+is to straighten the trunk, and maintain it when a burden is borne on
+the shoulders or back. It is for this reason that their common mass in
+the lower part of the back is so developed in men who usually carry
+heavy loads on the shoulders, and forms that powerful muscular mass
+of the loins, of which the prominence is visible beneath the skin and
+the aponeurosis of the latissimus dorsi (1, Fig. 73). In the neck,
+as already stated, the _complexus_ is the most important of the deep
+muscles in giving rise to the form and contour of this region.
+
+
+
+
+                            CHAPTER XVIII.
+
+                  MUSCLES OF THE SHOULDER AND ARMPIT.
+
+   The _deltoid_: its _form_, _thickness_, _actions_.--Muscular
+   form of the shoulder as a whole.--The deeper muscles
+   (_supraspinatus_ and _subscapularis_).--_Serratus magnus_
+   muscle: its relation to the armpit, its costal digitations; its
+   action in movements of the arm.--Forms of the region of the
+   armpit; prominence of the _coraco-brachialis_ muscle; relations
+   of the _biceps_ and _triceps_ to the armpit.
+
+
+The upper and outer part of the prominence of the shoulder is formed
+by a single powerful muscle, called the _deltoid_. Beneath this
+are several deep muscles which fill up the fossæ of the scapula
+(_supraspinatus_, _infraspinatus_, and _subscapularis_). But when the
+arm is raised and maintained in the horizontal position, the surface
+below the root of the arm dips into a cavity or pit, corresponding
+to the external prominence of the shoulder; this cavity, called the
+_armpit_, or _axilla_, has for a roof the skeleton of the shoulder
+covered by the deltoid, and for its walls--in front, the pectoral
+muscles, which adjoin the anterior border of the deltoid, and behind,
+the subscapularis and the latissimus dorsi, separated from the
+posterior border of the deltoid by the teres major muscle. On the inner
+side is a muscle applied to the wall of the thorax, the _serratus
+magnus_, and on the outer side is the humerus, covered by the _biceps_
+and _coraco-brachialis_ muscles. Of the muscles which we have named,
+some have already been studied in relation to the muscular structure of
+the trunk (great pectoral and latissimus dorsi); of the others, we will
+study the _deltoid_ and _serratus magnus_, in relation to the region of
+the shoulder and axilla.
+
+_Deltoid muscle._--This muscle is so called because it resembles the
+Greek letter delta, and is triangular in form; it is short, broad,
+thick, and shaped like half a cone to clasp the shoulder-joint. It
+arises above from the outer third of the anterior border of the
+clavicle (12, Fig. 68), from the acromio-clavicular articulation, from
+the convex border of the acromion, and from the entire extent of the
+posterior border of the spine of the scapula (18, Fig. 73). From this
+origin its fibres are directed downwards, the middle fibres vertically,
+the anterior or clavicular fibres downwards and backwards, and the
+posterior fibres obliquely forwards, to be inserted into the external
+surface of the humerus on a rough =V=-shaped groove, called the deltoid
+impression (page 68).
+
+  [Illustration: FIG. 74.
+
+   THE SUPERFICIAL MUSCLES OF THE SHOULDER AND THE LATERAL PORTION
+   OF THE TRUNK.--1, the latissimus dorsi;--2, the lumbo-sacral
+   aponeurosis;--3, 4, 4, the iliac and costal origins of the
+   latissimus dorsi;--5, 6, 7, the upper portion of the latissimus
+   dorsi;--8, the teres major;--9, 10, 11, the trapezius;--12, the
+   infraspinatus;--13, the teres minor;--14, 15, 16, the external
+   oblique of the abdomen;--17, 18, the anterior and interior
+   border of the same muscle;--19, its inferior internal angle
+   rounded (see page 199);--20, 20, serratus magnus;--21, the
+   pectoralis major;--22, the gluteus maximus;--23, the tensor
+   of the _fascia lata_;--24, the deltoid;--25, the platysma
+   myoides;--26, the sterno-cleido-mastoid.]
+
+This muscle is very thick, and is intersected by a vertical series of
+strong fibrous bands or septa, which may be seen as depressions beneath
+the skin in the contracted muscle. The action of the deltoid is to
+elevate the arm, separating it from the trunk and supporting it in the
+horizontal position; but while the middle fibres raise the arm directly
+outwards, the anterior fibres elevate it and carry it forwards, and the
+posterior fibres carry it backwards. It is necessary to remark that
+this muscle is never at right angles to the lever which it moves, but
+it always acts obliquely on the humerus. Hence, although very thick,
+the deltoid cannot act with great power; therefore the horizontal
+position of the arm produced by the action of the muscle is one which
+requires great effort and quickly produces fatigue. In order to
+understand the unfavourable arrangement of the deltoid with relation to
+its humeral lever, it is sufficient to compare it with that which the
+biceps presents relative to the forearm, and to see that the biceps,
+which acts obliquely on the radius, becomes perpendicular to that bone
+in proportion as flexion is carried on in the arm; and when the elbow
+forms a right angle, the biceps muscle is found in the most favourable
+condition to act with all possible force. In other words, the greatest
+_momentum_ of a muscle occurs when it is perpendicular to its
+lever; the deltoid muscle, therefore, does not possess much momentum.
+
+In pointing out the relations which the three borders of the deltoid
+present, we summarise the various details of the muscular contour of
+the shoulder:--1st. The _superior border_ of the deltoid, by its origin
+from the anterior border of the clavicle and the posterior border of
+the spine of the scapula, repeats the insertions of the trapezius,
+which is attached to the opposite lip and border of the same bones
+(Fig. 74). The clavicle, acromion, and spine of the scapula form a
+species of bony intersection between the trapezius and deltoid, and
+when the muscles are contracted produce a deep groove between the
+insertion of the trapezius and the origin of the deltoid. In animals
+which have no clavicle, and in which the spine of the scapula is
+not well developed, the fibres of the deltoid and trapezius are
+directly continuous. We observe an arrangement of this nature in the
+horse. 2nd. The _anterior border_ of the deltoid is separated from
+the corresponding border of the great pectoral muscle by a linear
+interval, very narrow below, but a little broader above, where it
+forms a small triangle, of which the base corresponds to the middle of
+the clavicle (Fig. 70). This interval, which becomes visible during
+the contraction of the two muscles when we endeavour to raise the
+arm upwards and forwards while it is held behind, as in the act of
+drawing a load, gives passage to a vein called the _cephalic_, and
+under such circumstances this vein becomes prominent and swollen. 3rd.
+The _posterior border_ of the deltoid forms one of the sides of the
+triangular space which we have studied in the region of the back, at
+the level of the infra-spinous fossa (Figs. 73 and 74); and, under its
+posterior border, pass successively on the one hand the infraspinatus
+and teres minor muscles, which pass directly beneath the deltoid, and
+on the other the teres major and latissimus dorsi muscles, which pass
+more deeply, separated from the deltoid by the long head of the triceps
+muscle (Fig. 75).
+
+Two muscles of the shoulder remain to be mentioned which are not
+visible on the model, but must at least be named in order to explain
+how the fossæ of the shoulder-blade are filled up. These are:--1st. The
+_supraspinatus_ muscle (11, Fig. 75), which occupies the supra-spinous
+fossa of the scapula, passes beneath the coraco-acromial arch, and
+is inserted into the uppermost facet of the great tuberosity of the
+humerus. 2nd. The _infraspinatus_ muscle occupies the infra-spinous
+fossa, and is partially concealed by the latissimus dorsi, trapezius,
+and deltoid. It is also bound down on the back of the scapula by a
+strong membrane derived from the deep fascia. It is inserted below the
+supraspinatus into the back of the great tuberosity of the humerus.
+3rd. The _subscapularis_ muscle (19, Fig. 68) occupies the subscapular
+fossa, and is inserted into the lesser tuberosity of the humerus.
+
+The _serratus magnus muscle_ (14, Fig. 68; 5, Fig. 70; 2, Fig. 71; 20,
+Fig. 73).--This muscle, applied to the lateral part of the thorax, is
+hidden throughout a great part of its extent by the scapula and the
+muscles of the chest and shoulder; but it becomes superficial at its
+lower part, in a series of prominent digitations and muscular bands,
+which form very characteristic features in the contour of the lateral
+region of the thorax. At the same time, as the muscle constitutes the
+inner wall of the armpit, we must describe it here in detail.
+
+The serratus magnus arises by nine fleshy slips from the outer surfaces
+of the upper eight ribs (an additional slip arising between the first
+and second ribs). From this origin the muscle, which forms a broad
+sheet, sweeps backwards round the ribs, to be inserted into the whole
+length of the vertebral border of the scapula. The five or six upper
+digitations of the muscle are hidden by the great pectoral muscle (21,
+Fig. 73), and only its three or four lowest digitations are visible on
+the side of the thorax between the borders of the great pectoral muscle
+in front and the latissimus dorsi behind; they interdigitate with the
+upper slips of origin of the external oblique muscle of the abdomen
+(20 and 16, Fig. 73). The alternations of origin of the serratus magnus
+and external oblique are seen when the muscle is contracted, as when
+the arm is thrust forward. When the arm is hanging loosely, or slightly
+raised, we see only three digitations of the serratus magnus; but when
+the arm is strongly elevated the great pectoral frequently leaves
+another uncovered.
+
+The action of this muscle is to fix the scapula, drawing this bone
+downwards and forwards, while the rhomboid, on the other hand, draws
+it upwards and backwards. Fixation of the scapula being necessary to
+afford a fixed point for the contraction of the muscles of the arm
+(particularly the biceps), it is easy to perceive that whenever the
+upper limb accomplishes a powerful effort, the lower digitations of
+the serratus magnus become clearly visible in the living model, as in
+a sword-thrust, wrestling, lifting from the ground a heavy body, or in
+pushing back an adversary, &c.
+
+The serratus magnus muscle forms the inner wall of the armpit or
+axilla, a cavity of which the anterior wall is represented by the
+pectoral muscles, and the posterior wall by the subscapularis, teres
+major, and latissimus dorsi. The cavity forms a triangular pyramid; its
+summit, directed upwards, corresponds in the skeleton to the interval
+between the first rib, the clavicle, and the upper border of the
+scapula. In a dissected subject this cavity is open inferiorly, but
+in the living model it is closed by the skin which forms the base of
+the pyramid, and which, in passing from the outer border of the great
+pectoral muscle to the border of the latissimus dorsi, is hollowed out
+so as to ascend in the space, into which it is drawn by its attachment
+to the strong, deep fascia of the axilla.
+
+To complete the description of the axilla we must say a few words
+concerning its boundaries, and the folds which correspond to the
+lines of junction of its walls. There is nothing more to add with
+regard to its anterior limit (formed by the great pectoral muscle) or
+its posterior limit (formed by the latissimus dorsi and teres major
+muscles clothing the axillary border of the scapula), but a word
+must be said of the external limit of the space which corresponds
+to the root of the arm. This is a comparatively thick surface, and
+corresponds to the upper part of the shaft of the humerus. The bone
+is covered by two muscles which descend from the scapula towards the
+anterior surface of the arm,--the _biceps_ and _coraco-brachialis_,
+which we will notice briefly. We will say, first of all, that the form
+of the coraco-brachialis is clearly visible beneath the skin of the
+armpit when the arm is strongly raised, as for example in a subject
+crucified, when it raises the depressed skin in the armpit. The skin is
+covered with hair more or less abundant, according to the individual,
+and it is a classic habit to omit this part of the hairy system in
+every representation of an elevated limb; but the artist should be
+convinced by the study of anatomy that he should never conform to the
+habit of tracing on the skin of the hollow of the armpit a fanciful
+contour, since this skin is smooth and regularly depressed, and only
+on its external part presents the fusiform muscular prominence of the
+coraco-brachialis, on the inner side of the anterior surface of the
+arm. The _biceps_ muscle escapes from under cover of the great pectoral
+muscle, and lies external to the coraco-brachialis more on the front of
+the limb.
+
+The _triceps_ muscle of the arm, which, by its long head, takes origin
+from the scapula, does not pass, like the biceps and coraco-brachialis,
+through the armpit, but appears behind it on the back of the arm,
+since, as we have already said, it passes between the teres minor
+posteriorly and the teres major and latissimus dorsi anteriorly (Figs.
+73 and 75).
+
+
+
+
+                             CHAPTER XIX.
+
+                          MUSCLES OF THE ARM.
+
+   1st. Anterior muscles: _Biceps_, its two heads; its fusiform
+   body; its bifurcation below (aponeurotic expansion and
+   tendon); its action (supinator and flexor of forearm);
+   influence of its aponeurotic expansion on the contour of the
+   forearm.--_Coraco-brachialis_, _brachialis anticus_. 2nd.
+   Posterior muscle: _Triceps brachialis_, its three portions, flat
+   surface formed by its inferior tendon; general contour of the
+   posterior surface of the arm; action of triceps. External form
+   of the arm; external and internal intermuscular grooves.
+
+
+The muscles of the arm form two distinct fleshy masses, a mass in front
+formed by the _biceps_, which occupies the entire length of the arm;
+by the _coraco-brachialis_, which occupies only the upper part; and
+lastly, by the _brachialis anticus_, which occupies the lower part; and
+a mass behind, formed by one muscle only, the _triceps_.
+
+The _biceps_ (12, Fig. 75, and 21, Fig. 70) is so called because it
+possesses two heads of origin, which are known by the names of the
+_long_ and _short heads_. The _long head_ of the muscle presents the
+form of a long tendon, which arises from the upper limit of the glenoid
+cavity of the scapula, and descends through the shoulder-joint and the
+bicipital groove of the humerus to the arm. The _short head_ of the
+biceps has a less complex course, and arises from the summit of the
+coracoid process, in common with the coraco-brachialis.
+
+  [Illustration: FIG. 75.
+
+   THE MUSCLES OF THE SHOULDER AND ARM (seen from the external
+   side).--1, the triceps brachialis;--2, its long head;--3, its
+   external head;--4, its attachment to the olecranon;--5, the
+   teres major;--5′, the teres minor;--6, the infraspinatus;--7,
+   8, 9, 10, the deltoid;--11, the supraspinatus;--12, the biceps
+   brachialis;--13, the brachialis anticus;--14, the supinator
+   longus;--15, extensor carpi radialis longior.]
+
+These two tendons (long and short head) descend in the outer wall of
+the axilla, covered by the great pectoral muscle (Fig. 70, page 197);
+a little above the lower border of this muscle the fleshy fibres appear
+and form two cylindrical bellies which descend and become united, at
+the level of the middle of the anterior surface of the arm, in one
+large mass, very marked in muscular subjects (12, Fig. 75). A short
+distance above the elbow-joint, a flat tendon of insertion succeeds
+to the fleshy muscle; it is at first broad, but soon divides into two
+parts, one aponeurotic, called the _semi-lunar fascia_ of the biceps;
+the other, a rounded tendon forming the chief insertion of the muscle.
+The aponeurotic expansion (2, Fig. 77) of the bicipital fascia is
+directed downwards and inwards over the common mass of the flexor
+muscles of the forearm, and soon becomes blended with the aponeurosis
+of the forearm; the tendon proper (3, Fig. 74) dips down in the hollow
+of the elbow between the internal and external muscles of the forearm,
+and is fixed to the bicipital tubercle of the radius (page 78, and Fig.
+21), upon which it turns to be inserted into the posterior part of the
+tubercle.
+
+The biceps muscle is essentially the flexor of the forearm on the arm.
+This action is evident, and known to all, and it is useless to dwell
+on it, except to recall the fact that the biceps, in acting on the
+forearm, is inserted perpendicularly on the lever which it moves, so
+that it is in the most favourable position for the exercise of all its
+power. But the contraction of the biceps produces along with flexion
+of the elbow two other movements to which it is important to direct
+attention. 1st. If the forearm is in pronation the tendon of the
+biceps is obviously twisted round the upper part of the radius, since
+it is inserted into the posterior part of the bicipital tubercle; the
+first effect produced, therefore, by its contraction is a rotation
+of the radius outwards, and a movement of supination; the biceps is,
+therefore, a supinator, and one of the most powerful. 2nd. Besides
+flexion at the elbow-joint and this movement of supination, the biceps
+muscle raises and draws inwards the humerus by its action on the
+shoulder-joint. The three separate movements are found in association
+with one another in such a movement as the act of raising the hand to
+the mouth.
+
+During the contraction of the biceps, its aponeurotic expansion is
+tightened, and binds down the mass of the flexor muscles of the forearm
+over which it passes; hence it marks on the inner surface of the
+fleshy part of this portion of the limb, two fingers’ breadth below the
+internal condyloid ridge, a distinct furrow, during the contraction of
+the muscle.
+
+The changes of form in the arm which accompany the contraction of the
+biceps are well known, and it is sufficient to recall the fact that
+the fleshy belly of this fusiform muscle is lengthened in the state of
+repose, becoming short and globular during contraction. Nothing is more
+striking, nor gives a better idea of the change of form in a muscle
+during contraction, than to examine the biceps in a model, who brings
+it gradually into action by flexing the forearm on the arm (Fig. 76).
+We then see on the anterior surface of the arm a kind of fleshy ball
+becoming more and more clearly marked, which hardens and swells up at
+the same time, so that it seems to mount up towards the upper part of
+the arm, to the inferior border of the great pectoral muscle.
+
+The _coraco-brachialis_ muscle forms a narrow fusiform fleshy mass,
+which occupies the upper part of the inner surface of the arm. It
+arises from the coracoid process of the scapula (alongside the short
+head of the biceps), and is inserted into the middle of the internal
+border of the humerus. When the arm is hanging loosely the lower half
+only of this muscle is visible on the subject, and its prominence is
+blended with that of the biceps, while its upper half is hidden within
+the axillary space, beneath the great pectoral muscle. It becomes
+visible beneath the skin of the armpit, however, when the arms are
+raised, as in the position on the cross, and we have already dwelt
+upon the contour which the fusiform muscular belly of this muscle
+presents in the outer wall of the axilla. When the coraco-brachialis
+contracts, its form becomes more prominent, like that of every muscle
+in contraction; but it is not more visible on this account, for as it
+draws the arm to the thorax against which it is applied, it conceals by
+this movement the region in which its prominence is marked.
+
+  [Illustration: FIG. 76.
+
+   A, the arm extended; B, the elbow flexed and the biceps
+   contracted.]
+
+The _brachialis anticus_ muscle (13, Fig. 75, and 4, 4, Fig.
+77).--Situated beneath the lower half of the biceps, which it overlaps
+on each side, this muscle is deeply placed, and covers the lower
+two-thirds of the anterior surface of the humerus, to which it is
+attached. The fleshy fibres descend almost to the level of the elbow,
+where they are replaced by a flat tendon, inserted into the front of
+the coronoid process of the ulna. As the ulna does not exhibit any
+of the lateral movements comprised in supination and pronation, the
+brachialis anticus is simply a flexor of the forearm, and when this
+movement is forcibly accomplished, it may be seen to swell up on each
+side of the lower part of the biceps.
+
+_Triceps muscle._--This muscle (21, 22, Fig. 73; 1, 2, 3, Fig. 75),
+which forms alone the entire muscular structure of the posterior
+surface of the arm, has been called the _triceps_ because it arises
+by three heads, separated above, united below; one central or median,
+called the _long head_, and two lateral parts, distinguished as the
+_external_ and _internal heads_. The _long head_ (2, Fig. 75), forming
+a thick and fusiform fleshy belly, arises by a stout tendon from the
+upper part of the axillary border of the scapula immediately below the
+glenoid cavity, and passes between the teres major and teres minor
+muscles to the back of the arm (page 223). At the level of the junction
+of the middle with the lower third of the arm, the fleshy belly
+terminates in a broad, flat tendon (1, Figs. 75 and 78) which forms the
+main insertion of the muscle, and receives the insertions of the two
+other portions of the muscle. The _external head_ (3, Fig. 75) arises
+from the upper part of the posterior surface of the humerus (above and
+to the outer side of the spiral groove), and is directed obliquely
+downwards and inwards to be attached to the external border of the main
+tendon almost as low down as the elbow. Lastly, the _internal head_
+(22, Fig. 73) arises from the lower part of the posterior surface of
+the humerus (below and to the inner side of the spiral groove), and is
+attached to the internal border and deep surface of the inferior common
+tendon. This tendon is inserted (4, Fig. 75) into the upper surface of
+the olecranon process of the ulna, and on either side of this it blends
+with the deep fascia of the forearm.
+
+The form of the posterior surface of the arm is greatly influenced
+by the presence of the inferior common tendon of the triceps, which,
+narrow and pointed towards its upper end, forms a large flat surface
+at the lower part of the arm. This flat surface is overlapped on each
+side by the prominence of the fleshy parts of the inner and outer
+heads. Above, in the upper two-thirds of the posterior surface of the
+arm, two fleshy bellies may be seen side by side, an outer one formed
+by the outer head, an inner one formed by the long head of the muscle.
+The inner head, more deeply placed, is only obvious in the lower third
+of the arm. These various details--viz., the tendinous flat surface
+above the olecranon, the muscular prominences which bound it on each
+side, and the two fleshy bellies which ascend above it--become visible
+in a marked degree when the subject forcibly extends the forearm on the
+arm, as in struggling against any resistance which causes the position
+of flexion to be maintained. It is hardly necessary to say that the
+triceps is essentially the extensor muscle of the forearm on the arm.
+
+It is not only for the purpose of a regular enumeration, but also
+with regard to the anatomical interpretation of their external forms,
+that we have classed the muscles of the arm as anterior and posterior.
+On each side of the arm at both inner and outer borders, a groove
+runs which separates the anterior from the posterior muscles. In
+each of these grooves is a fibrous partition called the internal and
+external intermuscular septum, which extends from the surface to the
+corresponding supra-condyloid ridge of the humerus, and serves to
+increase the area of muscular attachment. In muscular contraction,
+therefore, each septum or aponeurosis is slightly drawn towards
+the humerus, and on the surface two grooves are clearly seen, each
+corresponding to an interval, internally or externally, between the
+anterior and posterior muscles.
+
+The internal groove commences at the inferior extremity of the
+coraco-brachialis, and descends almost to the inner condyle. Above it
+is faintly marked, because the numerous nerves and vessels surrounded
+by cellular tissue fill up the intermuscular space at this level;
+below it spreads out, and tends to be confounded with the form of the
+internal part of the brachialis anticus.
+
+The external groove (Fig. 75) is short. It begins at the level of the
+lower extremity of the deltoid, and does not descend to the external
+condyle, because the highest muscles of the extensor group belonging
+to the forearm arise from the lower part of the outer border of the
+humerus, so that the groove is filled up by these muscles as they curve
+forwards towards the bend of the elbow.
+
+
+
+
+                              CHAPTER XX.
+
+                   MUSCLES OF THE FOREARM AND HAND.
+
+   Division into groups:--A. Anterior muscles of the forearm.
+   The _superficial muscles_, or _those arising from the inner
+   condyle_: pronator radii teres, flexor carpi radialis, palmaris
+   longus, and flexor carpi ulnaris. 2nd. The _deep muscles_
+   (flexors of the fingers and pronator quadratus). B. Posterior
+   muscles of the forearm. 1st. _External muscles_: supinator
+   longus (importance with regard to the forms of the external
+   region of elbow); the extensor carpi radialis, longior, and
+   brevior; the supinator radii brevis. 2nd. The _posterior
+   superficial muscles_: the extensor communis digitorum, extensor
+   minimi digiti, extensor carpi ulnaris, and anconeus.
+
+
+_Muscles of the Forearm._--The two bones of the forearm are covered
+by a series of muscles with fleshy bellies, generally fusiform,
+terminating inferiorly in tendons which are frequently very long, and
+become prominent in the region of the wrist. Some of these muscles move
+the forearm on the arm, or the radius on the ulna, but the action of
+the greater number is to move the hand on the forearm and the different
+segments of the fingers on each other. These muscles are divided into
+five series, each composed of four muscles, making the total number of
+muscles in the arm twenty altogether. We shall dwell chiefly upon the
+superficial muscles, a short mention being sufficient for the deeper
+ones. We distinguish first of all two groups, anterior and posterior:
+one on the front, the other on the back of the forearm. The anterior
+group is divisible into: 1st. An anterior superficial layer, of which
+each muscle will be studied; 2nd. An anterior deep layer, to which we
+will briefly refer. The posterior group may be subdivided into three:
+1st. An external layer; 2nd. A superficial posterior layer, which we
+must review in detail; and 3rd. A posterior deep layer, respecting
+which we shall only say sufficient to enable the reader to understand
+the shape of the wrist formed by the corresponding tendons.
+
+A. _ANTERIOR MUSCLES OF THE FOREARM._ I. _Anterior superficial
+muscles._--All these muscles arise by a common tendon from the
+_internal condyle_ of the humerus; their common origin does not
+appreciably extend above the level of the condyle, so that at the inner
+side of the elbow, contrary to what takes place on the outer side,
+the muscles of the forearm do not ascend on the corresponding side of
+the upper arm. If from the inner condyle we draw four lines, of which
+the first goes towards the middle of the radius, the second towards
+the outer border of the wrist, the third towards the middle, and the
+fourth towards the inner border of the wrist; these four lines, of
+which the first is very oblique and the others gradually approach the
+vertical, will give us the direction of each of these four anterior
+superficial muscles of the forearm, which are, in the order of the
+lines, from without inwards, the _pronator radii teres_, the _flexor
+carpi radialis_, the _palmaris longus_, and the _flexor carpi ulnaris_.
+
+  [Illustration:
+
+   FIG. 77.--THE ANTERIOR MUSCLES OF THE LEFT FOREARM.--1,
+   the biceps brachialis;--2, its aponeurotic expansion;--3,
+   its tendon;--4, 4, brachialis anticus;--5, the internal
+   head of the triceps;--6, pronator radii teres;--7, flexor
+   carpi radialis;--8, 9, palmaris longus;--10, flexor carpi
+   ulnaris;--11, its attachment to the pisiform bone;--12, 13,
+   supinator longus;--14 and 15, the extensor carpi radialis,
+   longior, and brevior;--16, the abductor longus pollicis;--17,
+   its tendon;--18, tendon of extensor longus pollicis;--19, 20,
+   21, the superficial flexor of the fingers and its tendons;--22,
+   tendons of the deep flexors;--23, 23, the lumbricales;--24,
+   abductor brevis pollicis;--26, flexor longus pollicis.]
+
+The _pronator teres_ (6, Fig. 77) is fleshy throughout the entire
+extent in which it is visible on the model; arising from the internal
+condyle, it is directed obliquely downwards and outwards, and
+disappears beneath the external muscles of the forearm (supinator
+longus) to be inserted into the radius (around which it is slightly
+twisted) in the middle of its external surface (impression for the
+pronator teres, page 78). Contracting, the pronator teres turns the
+radius forward and inwards, producing pronation. This muscle forms the
+inner side, very oblique, of a triangular pit, known as the _hollow
+of the elbow_, of which the outer side is formed by the supinator
+longus (12, Fig. 77). In this hollow the tendon of the biceps dips down
+(3, Fig. 77) along with the brachialis anticus (4, 4, Fig. 77) to be
+inserted into the bones of the forearm. The upper part of the pronator
+teres is crossed by the aponeurotic expansion of the biceps (2, Fig.
+77), and we have already dwelt on the particulars of external form
+which result from this arrangement.
+
+The _flexor carpi radialis_ (7, Fig. 77) arises from the inner condyle
+by a fusiform fleshy belly which descends obliquely to the middle of
+the forearm. It is replaced by a narrow, strong tendon which gains
+the outer part of the wrist, and then disappears beneath the annular
+ligament of the carpus, and, lying in a groove on the anterior surface
+of the trapezium, is inserted into the bases of the metacarpal bones
+of the fore and middle fingers. This muscle flexes the hand on the
+forearm; when it contracts, its tendon becomes very prominent and
+raises the skin at the lower part of the front of the forearm; it forms
+the first tendinous prominence that we meet at this level in passing
+from the radial to the ulnar border, and lies just internal to the
+groove in which the radial artery pulsates.
+
+The _palmaris longus_ (8, 9, Fig. 77) is much smaller than the
+preceding muscle; arising from the internal condyle, it forms a short
+fusiform fleshy belly (8) to which a long slender tendon succeeds.
+Descending almost vertically to the middle of the wrist, the tendon
+ends by being inserted into the annular ligament of the carpus and the
+fascia of the palm (9, Fig. 77). The palmaris longus flexes the hand
+on the forearm, and its tendon forms in contraction of the muscle a
+well-marked prominence situated in the middle of the lower part of the
+front of the forearm on the inner side of the tendon of the flexor
+carpi radialis. In some subjects this muscle is absent, and it is
+frequently subject to variations of form.
+
+The _flexor carpi ulnaris_ (10, 11, Fig. 77) arises not only from the
+inner condyle, like the three preceding muscles, but also (18, Fig.
+78) from the posterior border of the ulna (including the olecranon)
+process; it descends vertically over the ulna, and is inserted by
+tendinous and fleshy fibres into the pisiform bone of the carpus (11,
+Fig. 77). As its fleshy fibres continue down to its insertion the form
+of the muscle is not marked by a prominence such as those produced by
+the tendons of the preceding muscles; this muscle, therefore, helps
+to give a rounded form to the whole extent of the inner border of the
+forearm. It flexes the hand, and at the same time draws it inwards
+towards the inner side of the wrist.
+
+II. _Anterior deep muscles._--These muscles constitute a fleshy mass
+lying beneath the preceding superficial muscles, and terminate near
+the wrist in numerous tendons, which pass to the fingers; the tendons
+of the muscles appear to a slight extent on the model in the grooves
+between the tendons of the superficial muscles (19, 19, Fig. 77). Lower
+down the tendons of these muscles lie in the anterior groove of the
+carpus, bound down by the corresponding annular ligament, and after
+traversing the hollow of the palm of the hand, they are inserted into
+the phalanges of the fingers, presenting characteristic features which
+we will rapidly point out in the enumeration of these muscles.
+
+These deep muscles comprise, 1st, the _flexor sublimis digitorum_
+(19, Fig. 77), which divides below into four tendons, one for each
+finger (except the thumb); 2nd, the _flexor profundus digitorum_,
+which also divides into four tendons, one for each finger (except the
+thumb). On the anterior surface of each finger, therefore, we see two
+tendons--one superficial (23, Fig. 77) and the other deep. The first
+(flexor sublimis) presents at the level of the first phalanx (20, Fig.
+77) a slit or button-hole, through which the second passes (flexor
+profundus); owing to this arrangement the tendon of the deep flexor is
+inserted into the base of the third phalanx (22, Fig. 77); while the
+superficial flexor is inserted into the base of the second phalanx (21,
+Fig. 77). There is, indeed, a flexor muscle for each of the phalanges;
+the first phalanges of the fingers having special flexors in addition,
+the small _lumbricales_ muscles of the palm of the hand, which arise
+from the sides of the tendons of the flexor profundus digitorum in the
+palm of the hand.
+
+3rd. The _flexor longus pollicis_ (26, Fig. 77) arises in the forearm
+from the radius, and its tendon is inserted into the base of the second
+or last phalanx of the thumb. It gives no evidence of its existence
+on the surface. 4th. The _pronator quadratus_ muscle, a quadrilateral
+fleshy muscle, is disposed in a different manner to the preceding
+muscles, which must be raised in order to see it. It is formed by
+transverse fibres placed in the lower fourth of the forearm, and it
+passes from the anterior surface of the ulna to that of the radius. Its
+contraction produces pronation, rotating the radius over the lower part
+of the shaft of the ulna.
+
+B. _POSTERIOR MUSCLES OF THE FOREARM._ I. _External muscles._--These
+form the fleshy mass which covers the lower third of the outer border
+of the arm (Fig. 75, page 225) and descends along the outer border
+of the radius in the forearm. The group comprises four muscles--the
+_supinator longus_ (_brachio-radialis_), two _radial extensors of the
+carpus_, and the _supinator radii brevis_.
+
+Of these four muscles, one only is visible on the model throughout its
+entire extent--viz., 1st, the _supinator longus_ or _brachio-radialis_
+(14, Fig. 75; 12, 13, Fig. 77), which arises from the outer
+supra-condyloid border of the humerus, between the brachialis anticus
+in front and the triceps behind. It is noteworthy that on this side the
+muscles of the forearm ascend on the arm almost up to the insertion
+of the deltoid. The supinator longus enlarges as it descends, so that
+it presents its greatest size at the level of the external condyle,
+the prominence of which it completely conceals. It forms the outer
+vertical boundary (page 234) of the triangular hollow at the bend of
+the elbow. Just below the middle of the forearm, the fleshy fibres
+are replaced by a long tendon which lies on the radius, and (13, Fig.
+77) is finally inserted into the base of the styloid process of that
+bone. Notwithstanding its name, this muscle is not essentially a
+supinator; it acts in this way only when the forearm is in a position
+of complete pronation, and its proper action in this respect is to
+bring the forearm into a position between supination and pronation.
+Its principal function, however, is the flexion of the forearm on the
+arm, and in this movement its form is clearly shown externally in the
+form of a prominent band, which rises from the arm, and forms, on the
+antero-external part of the elbow, a strong fleshy mass, filling up the
+hollow produced by the flexion of the forearm on the arm. The supinator
+longus is the most important of the muscles of the forearm with regard
+to the part it takes in the external form of this region.
+
+The two next muscles (14 and 15, Fig. 77) are partly hidden by the
+preceding; they are the _radial extensors of the carpus_ (2 and
+3), distinguished as the _extensor carpi radialis_, _longior_ and
+_brevior_ (15, Fig. 75). They arise from the lower part of the outer
+supra-condyloid ridge of the humerus and from the outer condyle, and
+form fleshy masses (3 and 5, Fig. 78), which increase the prominence
+of the supinator longus, and help to conceal the outer condyle. At
+about the same level as in the case of the supinator longus, a tendon
+succeeds the fleshy belly of each of these muscles, and inclines a
+little backward (Fig. 78); having been crossed by the _extensor ossis
+metacarpi pollicis_, by the _extensor brevis pollicis_ (7 and 8, Fig.
+78), and by the _extensor longus pollicis_; each reaches the dorsal
+surface of the wrist, and is inserted into the base of the metacarpal
+bone of the index finger (extensor carpi radialis longior), and into
+the base of the metacarpal bone of the middle finger (extensor carpi
+radialis brevior, 6, Fig. 78).
+
+4th. Surrounding the upper part of the radius is a small deep
+muscle, which does not show on the model, and which we mention here
+only to point out that its presence increases the prominence of the
+muscular mass on the outer side of the elbow; this is the _supinator
+radii brevis_, formed by fibres which, arising from the humerus,
+elbow-joint, and ulna, are rolled round the back and outer side of
+the radius, and which acts so as to turn the bone backwards and thus
+produce supination.
+
+II. _Posterior superficial muscles_ (Fig. 78).--This group comprises
+the _extensor cemmunis digitorum_, the _extensor minimi digiti_, the
+_extensor carpi ulnaris_, and the _anconeus_. These four muscles arise
+from the external condyle, to which they are attached by a common
+tendon; from this origin they are directed downwards, the first almost
+vertically, the last (_anconeus_) very obliquely backwards and inwards.
+
+  [Illustration:
+
+   FIG. 78.--THE POSTERIOR MUSCLES OF THE LEFT FOREARM.--1, the
+   tendon of triceps brachialis;--2, supinator longus;--3 and
+   4, extensor carpi radialis longior;--5 and 6, extensor carpi
+   radialis brevior;--7 and 8, extensor ossis metacarpi pollicis
+   and extensor brevis pollicis;--9, 9, the extensor longus
+   pollicis;--10, 10, the annular ligament of the wrist (dorsal
+   aspect);--11, 12, the extensor communis digitorum and its
+   tendons;--13, the tendon of the extensor indicis;--14, the
+   tendon of the extensor minimi digiti;--15, 16, extensor carpi
+   ulnaris;--17, anconeus;--18, the flexor carpi ulnaris;--19, the
+   posterior border of the ulna;--20, olecranon;--21, the inner
+   condyle.]
+
+1st. The _extensor communis digitorum_ (11, Fig. 78) forms a long
+fusiform fleshy belly. In the lower third of the posterior surface of
+the forearm, it gives place to a tendon which soon subdivides into four
+bands. These remain in contact until they have passed a groove situated
+in the centre of the inferior extremity of the radius, and separate on
+the dorsal surface of the wrist, diverging so as to be attached to each
+of the four fingers. On the back of the hand the tendons of the middle,
+ring, and little fingers are joined together by two oblique tendinous
+slips directed obliquely downwards and outwards, from the fourth to the
+third, and from the third to the second tendon respectively. On the
+dorsal surface of the first phalanx of each finger (12, Fig. 78) the
+extensor tendon forms a membranous expansion, and thereafter divides
+into three slips, a central one inserted into the base of the second
+phalanx, and two lateral slips which unite again to be inserted into
+the base of the third phalanx. The tendons cover the backs of the
+knuckles and of the joints of the fingers.
+
+2nd. The _extensor minimi digiti_ is a small bundle of fleshy fibres
+lying adjacent to the preceding muscle, but distinctly detached from
+it. It gives rise to a separate tendon, which passes through a special
+groove beneath the posterior annular ligament between the lower ends
+of the radius and ulna. From the wrist it is directed towards the
+posterior surface of the little finger (14, Fig. 78), where it unites
+with the tendinous fasciculi from the common extensor tendon for the
+little finger, and joins in the formation of the membranous expansion
+on the dorsum of the first phalanx.
+
+3rd. The _extensor carpi ulnaris_ (15, Fig. 78) is a fusiform muscle
+arising from the external condyle and the posterior surface of the
+ulna. It is replaced by a tendon in the lower fourth of the forearm
+(15, Fig. 78). This tendon passes beneath the posterior annular
+ligament in a groove on the posterior surface of the ulna (10, Fig.
+78), and at the inner part of the dorsal surface of the carpus it
+terminates almost immediately by being inserted into the base of the
+metacarpal bone of the little finger (16, Fig. 78).
+
+These three muscles are extensors of the fingers and hand. If we
+examine a living model which has the arm folded on the trunk, the
+dorsal surface of the forearm being turned forwards, and which quickly
+moves the fingers and hand, we see clearly the movements of the fingers
+marked by muscular movements in the upper two-thirds of the posterior
+surface of the forearm. We can, by following their prominences in
+contraction, clearly recognise the fusiform bellies of these muscles.
+
+4th. The _anconeus_ occupies the upper part of the posterior
+surface of the forearm. As its name indicates (ἀγκὼν, olecranon,
+elbow), it is a muscle of the region of the elbow; it forms (17, Fig.
+78) a triangular fleshy mass, of which the apex is attached to the
+external condyle, and the base is inserted into the external surface
+of the olecranon, and corresponding part of the ulna (19, Fig. 78). As
+the ulna does not possess appreciably the movement of rotation, but
+shares only in flexion and extension of the elbow-joint, the anconeus
+situated behind the joint has no other action than that of extending
+the forearm on the arm. When this movement is forcibly produced, we
+see the anconeus clearly marked by a triangular prominence, of which
+the upper border, the shortest, is united with the prominence of the
+triceps; and we have already mentioned the anatomical fact that the
+inferior portion of the triceps is directly continuous in the forearm
+with the anconeus muscle.
+
+
+
+
+                             CHAPTER XXI.
+
+            MUSCLES OF THE FOREARM AND HAND (_continued_).
+
+   3rd. The posterior deep muscles of the forearm; their tendons
+   at the level of the wrist (_anatomical snuff-box_).--Muscles of
+   the hand;--1st. Muscles of the thumb, or _thenar eminence_. 2nd.
+   Muscles of the little finger, or _hypothenar eminence_. 3. Short
+   muscles of the palm (_lumbricales_ and _interossei_).
+
+
+III. _The deep posterior muscles_ of the forearm, with regard to
+external form, are important only in the arrangement of their tendons
+in the wrist and hand; for this reason we describe them in this chapter
+along with the muscular structures of the hand and fingers.
+
+As in the other regions, we find in the deep part of the back of the
+forearm, four muscles. Proceeding from without inwards they are--the
+_extensor ossis metacarpi pollicis_, the _extensor brevis pollicis_,
+the _extensor longus pollicis_, and the _extensor indicis_. The fleshy
+bellies of these muscles are almost completely hidden beneath the
+posterior superficial muscles; but their tendons, at least those of the
+first three, emerge beneath the external border of the common extensor
+of the fingers, and their form is shown (7 and 8, Fig. 78) by details
+of great importance on the outer side of the dorsal aspect of the
+wrist.
+
+The two first (7 and 8, Fig. 78), the _extensor ossis metacarpi
+pollicis_ (7) and the _extensor brevis pollicis_ (8), must be described
+together, as their fleshy parts and tendons are placed together and
+are almost united throughout the greater extent of their course. These
+two muscles emerge in the lower third of the forearm, at the outer
+border of the common extensor of the fingers; and they form at this
+point, at the junction of the posterior surface with the outer border
+of the forearm, an oblong eminence, which is soon succeeded by a double
+tendon. Crossing the tendons of the radial extensors of the wrist, this
+double tendon is directed towards the outer surface of the lower end
+of the radius, where it passes through a groove (10) converted into
+a canal by the posterior annular ligament of the wrist. At the outer
+border of the wrist these two tendons form a prominence, well marked
+beneath the skin, when the thumb is separated from the other fingers.
+Finally, at the base of the metacarpal bone of the thumb these tendons
+separate, one, that of the _extensor ossis metacarpi pollicis_, being
+inserted into the base of the metacarpal bone, while the other, that of
+the _extensor brevis pollicis_, passes over the first metacarpal bone
+to be inserted into the base of the first phalanx of the thumb (8, at
+the level of the thumb, Fig. 78).
+
+The _extensor longus pollicis_ (9, Fig. 78) emerges, like the preceding
+tendons, on the outer side of the common extensor, but lower down, on
+the back of the wrist; its tendon only becomes superficial at this
+point, and it is directed obliquely downwards through a prominent
+deep groove on the posterior surface of the lower end of the radius,
+where it is covered by the posterior annular ligament. On the back
+of the wrist the tendon is directed obliquely outwards, crossing the
+tendons of the radial extensors of the wrist, to reach the base of the
+metacarpal bone of the thumb, where it lies parallel to the tendon of
+the extensor brevis pollicis. Descending lower than this tendon it is
+finally inserted into the second or terminal phalanx of the thumb (9,
+Fig. 78).
+
+The tendons of the extensor ossis metacarpi and extensor brevis
+pollicis on the one hand, and the extensor longus pollicis on the
+other, form on the outer part of the back of the wrist a triangular
+figure, of which the apex corresponds to the upper end of the thumb,
+and the base to the lower end of the radius. When we separate the thumb
+strongly from the index finger--that is to say, when we contract the
+three small muscles which we have been studying--the corresponding
+tendons mark the borders of this triangle in the form of prominent
+cords, between which is a deep concavity; to this depression is given
+the name of the _anatomical snuff-box_ (4, Fig. 78).
+
+The _extensor indicis_ is not visible on the model; it is deeply
+situated beneath the common extensor of the fingers, and terminates
+in a tendon (13, Fig. 78) which unites with the tendinous fibres from
+the common extensor to the index finger. It is to this muscle that
+the index finger owes its power of extension independent of the other
+fingers, and of performing the functions which have given it the name
+of the index or indicating finger. It is to be noted that in separate
+extension of the index finger (with flexion of the others) the tendon
+of the extensor communis digitorum in the back of the hand gets curved
+outwards, by being pulled into line with the extended index finger by
+the traction of the tendon of the extensor indicis (Macewen).
+
+  [Illustration: FIG. 79.
+
+   MUSCLES OF THE HAND (palmar surface).--2, abductor pollicis
+   (cut);--3, opponens pollicis;--4, flexor brevis pollicis;--5,
+   adductor obliquus pollicis;--6, adductor transversus
+   pollicis;--7, deep flexor tendons and lumbrical muscles;--8,
+   flexor tendons on finger;--9, flexor longus pollicis;--10,
+   abductor minimi digiti;--11, flexor brevis minimi digiti;--12,
+   pisiform bone.]
+
+_Muscles of the hand._--The numerous muscles belonging to the hand
+form an interesting study in relation to the mechanism of the multiple
+and delicate movements of the fingers, but as the various details of
+their complex arrangement do not show very plainly on the surface we
+may confine our study of them to an enumeration of their principal
+features.
+
+The dorsal region of the hand (Fig. 78) does not possess any fleshy
+muscles, but only presents the tendons belonging to the muscles of
+the forearm. The arrangement of the tendons after passing beneath the
+posterior annular ligament has already been described (pp. 245–6).
+Notice should be taken of an arch of veins lying superficial to the
+tendons. This venous arch receives the veins from the fingers, and is
+variable in its arrangement and outline.
+
+On the other hand, the anterior or palmar region of the hand possesses,
+beside the tendons of the muscles of the forearm, numerous small
+muscles, which are divided into three groups:--1st, an external group
+associated with the thumb, forming the fleshy prominence known as the
+_thenar eminence_; 2nd, an internal group, belonging to the little
+finger, forming the _hypothenar eminence_; 3rd, a middle and deeper
+group, formed by small muscles belonging to the fingers, and placed
+deep in the hand beneath the thick _palmar fascia_, which, occupying
+the hollow of the palm, fills up the space between the thenar and
+hypothenar eminences (Fig. 79).
+
+1st. The _thenar eminence_ (2–5, Fig. 79) is of a long ovoid form,
+with the large superior extremity corresponding to the carpus, and
+the smaller inferior extremity corresponding to the base of the
+first phalanx of the thumb. It is formed by six muscles, namely, the
+_abductor pollicis_ (24, Fig. 77; 2, Fig. 79), which proceeds from
+the trapezium and annular ligament to the outer side of the first
+phalanx of the thumb; the _opponens pollicis_ (3, Fig. 79), with a
+similar origin, inserted into the entire length of the outer border
+of the first metacarpal bone, so that its contraction draws the whole
+thumb (phalanges and metacarpal bone) towards the palm of the hand,
+and thus opposes it to the other fingers; the _flexor brevis pollicis_
+(superficial part) (4, Fig. 79), which proceeds from the annular
+ligament to the base of the first phalanx; the _adductor obliquus
+pollicis_ (5, Fig. 79), arising from the carpus and heads of the
+metacarpal bones, and inserted into the inner side of the first phalanx
+of the thumb; the _adductor transversus pollicis_ (6, Fig. 79), a
+muscle remarkable for its arrangement, for it arises from the middle of
+the palm of the hand, from the anterior surface of the third metacarpal
+bone, and forming a comparatively broad fleshy mass, extends outwards
+to be inserted along with the adductor obliquus into the inner side of
+the base of the first phalanx of the thumb; and finally a small muscle
+deeply placed in the space between the first and second metacarpal
+bones, and known as the _deep part of the flexor brevis pollicis_ (or
+the _interosseus primus volaris_).
+
+2nd. The _hypothenar eminence_ is long and elliptical in form, but
+smaller than the thenar eminence; it is covered in part by a small
+muscle which is not shown by any external prominence, but only by
+the folds which it marks in the skin during its contraction; this is
+the _palmaris brevis_, formed of transverse fibres, which, arising
+from the inner border of the palmar fascia, is inserted into the deep
+surface of the skin on the inner border of the hand. The contraction of
+its fibres draws the skin of the part upwards and forms an irregular
+vertical furrow, so that the prominence of the skin of the upper part
+of the hypothenar eminence becomes more clearly marked. The hypothenar
+eminence itself is formed by three small muscles vertically arranged
+over the fifth metacarpal bone:--1, the _abductor minimi digiti_ (28,
+Fig. 77; 10, Fig. 79), passing from the pisiform bone to the inner side
+of the first phalanx of the little finger; 2, the _flexor brevis minimi
+digiti_ (27, Fig. 77; 11, Fig. 79), passing from the prominence of the
+unciform bone to the same phalanx; and lastly, 3, the _opponens minimi
+digiti_, arising from the unciform bone and inserted into the entire
+length of the fifth metacarpal bone, so that its contraction slightly
+draws outwards the whole of the little finger, and opposes it to a
+certain degree to the thumb.
+
+3rd. The muscles of the middle region of the palm of the hand are in
+two series. One set is arranged between the tendons of the _flexor
+profundus digitorum_ muscle (see anterior deep muscles of the forearm,
+page 237) as small fusiform muscles, which have been compared to the
+form of a worm--hence their name of _lumbricales_ (7, Fig. 79). The
+others are arranged in the spaces between the metacarpal bones, and are
+known as the _interosseous_ muscles.
+
+The _lumbricales_ muscles, as Figure 77 shows (23, 23), are four in
+number--one for each of the four fingers. Their upper ends are attached
+to the deep flexor tendons; and from this origin they descend to
+reach the outer or radial border of the first phalanx of each finger.
+Sweeping round the knuckle on its outer side, each tendon is inserted
+into the metacarpo-phalangeal capsule, the outer side of the base of
+the first phalanx, and into the expansion of the extensor tendon on the
+dorsum of the first phalanx of each finger. In consequence of this mode
+of insertion each muscle is a flexor of the metacarpo-phalangeal joint,
+and in addition, because of its connection with the extensor tendon, it
+is at the same time an extensor of the inter-phalangeal joints.
+
+The _interosseous muscles_ are seven in number, divided into two
+series, dorsal and palmar. The _dorsal_ muscles, four in number, are
+found one in each interosseous space between the metacarpal bones. The
+three _palmar_ interosseous muscles occupy the three inner spaces.
+They arise from the sides of the metacarpal bones (the dorsal muscles
+by double origins, the palmar muscles by single heads from the inner
+three metacarpal bones); and they are inserted in the same way as the
+lumbrical muscles into the fingers, so as to act as flexors of the
+metacarpo-phalangeal, and extensors of the inter-phalangeal joints. The
+several muscles pass in relation to the sides of the knuckles in a way
+that need not be detailed here, so as to occupy positions which enable
+them to act so as to separate or draw together the fingers. The dorsal
+interossei muscles serve to separate the fingers from each other, while
+the palmar serve to bring them together; or, to be more precise, the
+dorsal muscles abduct the fingers from the middle line of the middle
+finger, while the palmar muscles adduct the fingers on which they act
+(third, fourth, and fifth) towards the axis of the middle finger.
+
+
+
+
+                             CHAPTER XXII.
+
+                   MUSCLES OF THE PELVIS AND THIGH.
+
+   _The Buttock._--_Gluteus maximus_, its thickness and form; its
+   relations to the great trochanter.--_Gluteus medius._--The
+   subjacent muscles (_gluteus minimus_, _pyriformis_,
+   etc.).--Muscles of the thigh; 1st, External region _tensor
+   fasciæ latæ_ (_vaginæ femoris_), its importance with regard
+   to external form; aponeurosis of _fascia lata_; 2nd, Anterior
+   region, _sartorius_, peculiarities of this muscle during
+   contraction; _quadriceps extensor_ (_rectus_, _vastus internus_,
+   _vastus externus_, _crureus_); 3rd, Internal region, the
+   _adductors_; 4th, Posterior region, _hamstring_ muscles
+   (_biceps_, _semi-tendinosus_, and _semi-membranosus_).
+
+
+_Muscles of the Pelvis._--The muscles of the pelvis visible on the
+model are all situated on the posterior surface of that part of the
+skeleton, and form the buttock, or _gluteal region_. In front the
+anterior wall of the abdomen, descending to Poupart’s ligament and the
+pubis (Fig. 70, page 197), conceals the muscles which proceed from the
+interior of the pelvis towards the thigh--muscles of which a short
+sketch will be given along with those of the front of the thigh.
+
+Of the muscles of the gluteal region two only are superficial and well
+marked on the model--viz., the _gluteus maximus_ and _gluteus medius_.
+
+The _gluteus maximus muscle_ (Fig. 72, page 201) is the largest and
+thickest of all the muscles of the body. It is composed of large fleshy
+fibres directed obliquely from the sacro-iliac region towards the upper
+part of the femur. Its fibres arise from the posterior extremity of the
+crest of the ilium (4, Fig. 34, page 107), by an aponeurosis from the
+back of the sacrum, from the sacrum itself, and from the sacro-sciatic
+ligament. The coarse fleshy fibres are directed downwards and outwards
+through the gluteal region (Fig. 67). At the level of the great
+trochanter these fibres are for the most part inserted into a broad,
+thick, tendinous lamina, which is continuous with the aponeurosis of
+the thigh or _fascia lata_. The lower and deeper part of the muscle is
+inserted directly into the gluteal ridge of the femur (page 133). The
+gluteus maximus muscle presents four borders: (1) an _internal border_,
+corresponding to its origin, and convex inwards, and (2) an _external
+border_, also slightly convex at its insertion. This border corresponds
+to the line along which the fleshy fibres terminate; it forms a
+prominence, which curves posteriorly round the great trochanter. When
+we have enumerated the muscles lying beneath the gluteus maximus, it
+will be more easy to understand how the muscular structure of the
+gluteal region as a whole is so prominent that the great trochanter
+actually forms on the model the centre of a depressed area, bounded
+behind and above by the prominence of the gluteal muscles, and in
+front by the tensor muscle of the fascia lata (see _Muscles of the
+thigh_). (3) The _inferior border_ of the gluteus maximus is thick,
+and forms an oblique elevation, beneath which the posterior muscles of
+the thigh emerge; it is this which helps to form the lower limit of
+the prominence of the buttock. In the erect position the lower limit
+of the gluteal region is indicated by a transverse fold (_the fold of
+the nates_). This line runs diagonally across the lower border of the
+gluteus maximus, and is produced not by the edge, but by the weight
+of the relaxed muscle, and the fat which covers it. (4) The _superior
+border_ is thin (Fig. 74, page 217), and is continuous with the fascia
+lata, which covers the gluteus medius, so that its prominence is little
+marked on the model, being more or less lost in the area corresponding
+to the position of the gluteus medius muscle.
+
+The _gluteus maximus_ is an extensor of the thigh on the pelvis. In the
+upright position it supports the pelvis behind and prevents it from
+inclining forwards. It is by its action that the trunk is raised so as
+to be in the same line as the upright lower limb. The gluteus maximus
+is therefore the muscle of the upright position, and we observe the
+large size which it presents in the human subject compared with its
+small proportions in animals which do not adopt the biped attitude.
+
+The _gluteus medius muscle_ is situated both above and beneath that
+of the gluteus maximus--that is to say, the postero-inferior part
+is covered by the preceding muscle, but its antero-superior part is
+superficially placed. This latter part (Fig. 74, between 22 and 23)
+is, however, covered by the thick fascia lata of the thigh, which
+binds down the muscle to the dorsum ilii. Arising from the anterior
+three-fourths of the crest of the ilium, and from the dorsum ilii as
+well as from the fascia over it, the fibres of the gluteus medius
+descend, converging towards the great trochanter, into the external
+surface of which they are inserted by a thick aponeurotic tendon. The
+fleshy fibres cease a little above the great trochanter so as to form
+a prominence along a curved line with its concavity downwards, which
+forms the superior boundary of the depression corresponding to the
+region of the great trochanter, referred to above. The gluteus medius,
+by its posterior fibres, acts like the gluteus maximus; by its anterior
+fibres it draws the thigh outwards, acting as an abductor.
+
+  [Illustration: FIG. 80.
+
+   THE DEEP GLUTEAL MUSCLES.--1, Dorsum ilii;--2, sacrum;--3,
+   posterior sacro-iliac ligament;--4, tuberosity of ischium;--5,
+   great, 6, lesser sacro-sciatic ligament;--7, great
+   trochanter;--8, gluteus minimus;--9, pyriformis;--10, 11, 12,
+   gemelli and obturator internus 13, quadratus femoris;--14,
+   adductor magnus;--15, vastus externus;--16, biceps and
+   semi-tendinosus--17, gracilis;--18, semi-membranosus.]
+
+The gluteus maximus and gluteus medius muscles conceal a series of deep
+muscles filling up the large space which we observe on the skeleton
+between the great trochanter and the pelvic wall. These muscles, which
+we only need to enumerate in order to understand the importance of the
+prominence of the buttock, are, taking them in order, as follows--the
+_gluteus minimus_, which lies exactly beneath the gluteus medius, and
+proceeds from the dorsum ilii to the superior and anterior border
+of the great trochanter; the _pyriformis_, which arises within the
+pelvis from the anterior surface of the sacrum, escapes from the pelvis
+through the great sciatic notch, and is directed obliquely towards
+the great trochanter, into the upper border of which its tendon is
+inserted; the _obturator internus_, which proceeds also from the
+interior of the pelvis, is reflected over the lesser sciatic notch and
+is inserted into the internal surface of the great trochanter along
+with two accessory muscles, the _gemelli_; and finally, the _quadratus
+femoris_, formed by short horizontal fibres, which extends from the
+outer part of the tuberosity of the ischium to the posterior surface of
+the femur between the two trochanters.
+
+_Muscles of the thigh._--The muscles of the thigh are arranged around
+the femur, and frequently in a direction so oblique that they appear
+in one portion, for example, on the front, and in another portion
+on the inner side of the thigh. We can, however, class them in four
+series--external, comprising the _tensor vaginæ femoris_ (_fasciæ
+latæ_); anterior, comprising the _sartorius_ and _quadriceps extensor_;
+internal, comprising the _adductors_; and posterior, comprising the
+_biceps_, the _semi-membranosus_, and the _semi-tendinosus_.
+
+  [Illustration: FIG. 81.
+
+   THE MUSCLES OF THE ANTERIOR SURFACE OF THE RIGHT THIGH.--1, the
+   iliacus;--2, the psoas;--3, the tensor vaginæ femoris;--4, its
+   tendon (fascia lata);--5, the sartorius;--6, the rectus (long
+   head of quadriceps;--7, vastus externus (the external head);--8,
+   vastus internus (the internal head);--9, the gracilis;--10, the
+   adductor longus;--11, the pectineus.]
+
+I. _Outer side of the thigh._ The _tensor vaginæ femoris muscle_
+(3, Fig. 81).--This muscle lies in the plane of the gluteus maximus
+(23, Fig. 74, page 217), and forms a distinct prominence in front of
+the great trochanter. It arises from the anterior superior spine of
+the ilium, and is directed downwards and slightly backwards on the
+outer side of the thigh, to terminate a short way below the level
+of the great trochanter by being inserted into the broad and thick
+aponeurosis--the _fascia lata_--which covers this region (4, Fig. 81).
+This aponeurosis is specially thickened by the addition of vertical
+fibres, which form a tendon of insertion known as the _ilio-tibial_
+band. This band descends to the outer side of the knee as a distinct
+prominent tendon, which is inserted finally into the outer tuberosity
+of the tibia (see page 135). This muscle rotates outwards the thigh
+and the whole lower limb, and contributes also to the flexion of the
+thigh on the pelvis; therefore, when the thigh is extended and not
+turned inwards, the tensor muscle forms beneath the iliac spine a long
+muscular elevation, but when it is in action its form becomes short and
+broad, and forms a characteristic globular mass. This contrast in the
+form of the tensor muscle in repose and in action has been beautifully
+shown on the Gladiator, in which there is contraction of the tensor of
+the right thigh and relaxation of that of the left.
+
+The ilio-tibial band and the aponeurosis of the fascia lata cover,
+on the outer side of the thigh, the large fleshy mass of the _vastus
+externus_ (a part of the quadriceps extensor muscle), which belongs
+to the anterior region of the thigh. This muscle, thus covered in,
+is shown throughout its entire extent on the surface. Though covered
+by the fascia lata, it forms a marked convexity on the outer side of
+the thigh, as a gentle curve in women, and a strongly bowed line in
+well-developed, muscular men.
+
+II. _Front of the Thigh._ The _sartorius muscle_ (5, Figs. 81, and 23,
+Fig. 70, page 197).--This is the longest muscle in the human body. It
+forms a narrow fleshy band, which arises from the anterior superior
+iliac spine, and is directed obliquely downwards and inwards. Crossing
+the front of the thigh obliquely, it descends round the inner side of
+the knee over the inner condyle of the femur (Fig. 86), describing a
+curve with the concavity forward. It finally terminates at the upper
+part of the inner surface of the shaft of the tibia in a flat tendon
+(19 and 20, Fig. 86) which sweeps forward to be inserted into that bone
+just below the inner tuberosity in front of and along with the gracilis
+and semi-tendinosus muscles.
+
+The sartorius flexes and abducts the thigh on the pelvis, and flexes
+the leg on the thigh; so that it gives to the lower limb a position
+similar to that of a tailor when seated, hence the name of this muscle
+(_sartor_, a tailor). With regard to surface form, this muscle is
+indicated externally in a peculiar manner. When it contracts, only its
+superior extremity presents a superficial prominence; throughout the
+rest of its extent, the presence of the muscle, lying in the depressed
+groove between the quadriceps extensor in front and the adductor
+muscles on the inner side, is indicated during contraction by a large
+shallow furrow, particularly noticeable on the inner side of the thigh,
+at the junction of the upper two-thirds with the lower third.
+
+_Quadriceps extensor_ (6, 7, 8, Fig. 81).--The quadriceps extensor
+muscle belongs to the outer and inner regions of the thigh as well
+as to the front of the limb, but the element of the muscle of most
+importance in relation to external form--the _rectus femoris_--is
+situated anteriorly. The muscle, as its name implies, is composed of
+four portions: one, the _rectus_, in the middle; the _vastus internus_
+and the _vastus externus_, on each side; and the _crureus_, the deepest
+part, concealed by the other portions of the muscle.
+
+The _rectus femoris_ (21, Fig. 70, and 6, Fig. 81) is long and fusiform
+in shape--that is to say, larger at its centre than at its extremities.
+Its superior extremity, the more slender of the two, arises by a double
+tendon from the anterior inferior iliac spine and the dorsum ilii, and
+appears on the front of the thigh between the tensor fasciæ femoris
+and the sartorius muscles. Lying in the angular space which separates
+these two muscles (Fig. 81), the rectus descends vertically on the
+front of the thigh, and about four inches above the patella forms a
+broad tendon (Figs. 81 and 84), the borders of which give insertion on
+either side to the vastus internus and vastus externus muscles, while
+its deep surface gives insertion to the crureus muscle, and its base
+broadens out to be inserted into the patella. From the lower end of
+the patella a broad ligament--_the ligament of the patella_--arises
+(page 134), which is inserted into the tubercle of the tibia; it
+follows, therefore, that by means of the tendon of the rectus femoris,
+the patella, and the ligament of the patella, the quadriceps extensor
+muscle is eventually inserted into the tibia (Fig. 45, page 137).
+
+The _vastus internus muscle_ (8, Fig. 81) is a very large fleshy mass,
+which covers the inner side of the femur. Arising from the inner lip of
+the linea aspera of the femur, from the edge of the bone (spiral line)
+above, and from the internal supra-condyloid ridge below, its muscular
+fibres are directed downwards and forwards, to be inserted into the
+deep surface and the inner border of the tendon of the rectus femoris,
+into the side of the patella, and into the capsule of the knee-joint.
+It conceals the crureus and partly blends with that muscle. The outline
+of the vastus internus is easily discernible on the surface, forming a
+somewhat triangular, convex, and rounded contour; bounded internally
+by the furrow of the sartorius, externally by a vertical line where
+it joins the tendon of the rectus femoris, and below by its lower
+border, it forms a well-marked rounded line sweeping outwards over the
+internal condyle of the femur to the side of the patella. These details
+are of great importance in regard to the contour of the region above
+the patella, and are in marked contrast, as we shall see, with the
+arrangement presented at the same level by the lower part of the vastus
+externus.
+
+The _vastus externus_ (7, Fig. 81) lies external to the rectus
+femoris, and conceals the crureus, with which its deep surface is
+partially blended. Its origin, which underlies the tensor fasciæ
+femoris and the ilio-tibial band, is from the upper half of the shaft
+of the femur, from the outer lip of the linea aspera. Its fibres sweep
+downwards and slightly forwards to be inserted into the tendon of the
+rectus, the patella, and the capsule of the knee-joint. The line along
+which it is inserted into the rectus tendon describes a curve of which
+the convexity looks towards the supero-external angle of the patella,
+from which it is separated by a considerable interval (Figs. 81 and
+85). Consequently on the surface the flat surface above the patella
+forms a sort of triangle, of which the borders are very different,
+the inner border being vertical, the outer one oblique, curved, and
+higher in position; the base of the triangle corresponds to the patella
+and the lateral parts of the capsule of the knee-joint; its truncated
+summit corresponds to the inferior extremity of the fleshy part of the
+rectus; and the borders of this flat surface, formed by the fleshy
+insertions of the vasti muscles, become very prominent when the leg is
+forcibly straightened on the thigh.
+
+The _crureus_ muscle, deeply placed, is the fourth element in the
+quadriceps muscle. It arises from the upper three-fourths of the shaft
+of the femur, externally and in front, and forms a thick, fleshy mass,
+responsible to a great extent for the general contour of the front
+and sides of the thigh, though it is not actually noticeable directly
+on the surface. It is almost wholly concealed by the three previous
+muscles. It is partially blended on each side with the vasti muscles;
+and it is inserted as well into the deep surface of the tendon of the
+rectus femoris. It is hardly necessary to point out, since it is clear
+from its anatomical arrangement, that the quadriceps muscle, passing by
+means of the patella and the patellar ligament to the tubercle of the
+tibia, is essentially the extensor muscle of the leg.
+
+It is to be noted that the two vasti muscles have a very different
+effect in the shaping of the contours of the thigh. The vastus externus
+has its greatest prominence well above the patella on the outer side:
+the most prominent part of the vastus internus is formed by its lowest
+fibres, as they sweep across over the inner condyle of the femur.
+
+III. _The inner side of the thigh._ The _adductor muscles_.--We
+understand by _the adductors_ the numerous muscles that occupy the
+inner part of the thigh, and which, passing down from the pubis and
+ischium along the entire length of the femur, fill up the triangular
+space which appears in the skeleton between the inner surface of the
+femur and the pubic part of the hip-bone. Some of the muscles of this
+series take the special name of adductors. We will study in succession
+three muscles clearly visible on the model--viz. the _pectineus_, the
+_adductor longus_, and the _gracilis_; afterwards we will mention
+briefly the muscles almost hidden by the preceding--namely, the
+_adductor brevis_ and the _adductor magnus_ muscles.
+
+  [Illustration: FIG. 82.
+
+   THE POPLITEAL REGION AND POSTERIOR SURFACE OF THE RIGHT LEG.--1,
+   internal gastrocnemius;--2, external gastrocnemius;--3,
+   space between gastrocnemii;--4, 5, tendo Achillis;--6, 7, 7,
+   plantaris muscle and its tendon;--8, tendons of deep muscles
+   (common flexor and posterior tibial);--9, peroneus longus;--10,
+   peroneus brevis;--11, soleus;--12, biceps femoris;--13,
+   semi-tendinosus;--14, semi-membranosus;--15, gracilis;--16,
+   sartorius.]
+
+The _pectineus muscle_ (22, Fig. 70, and 11, Fig. 81), the first and
+shortest of the muscles of this region, is a broad fleshy band which
+extends from the horizontal ramus of the pubis to the upper part of
+the shaft of the femur (to a rough line passing from the linea aspera
+to the lesser trochanter). The lower part of this muscle is hidden by
+the sartorius, and the upper part does not show itself clearly beneath
+the skin, being covered by the large vessels of the thigh, and also in
+most cases by a quantity of fat. The pectineus forms the middle part of
+the floor of a triangular space in the upper third of the thigh, with
+its apex below, known in surgical anatomy as _Scarpa’s triangle_, which
+is bounded externally by the sartorius muscle. The base of the triangle
+corresponds to the groin, and is formed by Poupart’s ligament. The
+outer part of the floor of the triangle is formed by a large muscle, of
+which the greater part is situated in the cavity of the abdomen. This
+is the _ilio-psoas_ muscle (1 and 2, Fig. 81), which arises from the
+lateral parts of the lumbar vertebræ (_psoas_) and from the iliac fossa
+(_iliacus_), passes beneath Poupart’s ligament (page 199), and after
+traversing Scarpa’s triangle is inserted into the lesser trochanter of
+the femur. This muscle is not visible superficially except just below
+and internal to the anterior superior iliac spine, where it forms a
+slight bulging beneath the skin.
+
+The inner part of the floor of Scarpa’s triangle is formed by the
+_adductor longus_, triangular in shape (10, Fig. 81); arising by a
+narrow tendon from the angle of the pubis, it is inserted, beneath the
+sartorius, into the middle portion of the linea aspera of the femur.
+
+The _gracilis_ is visible throughout its entire length on the inner
+surface of the thigh (9, Fig. 81). It forms a long slender fleshy
+band, broader above and narrower below. Arising from the symphysis and
+descending ramus of the pubis, it descends vertically; a little above
+the inner condyle of the femur it is replaced by a narrow tendon (15,
+Fig. 82), which sweeps round the condyle, behind the sartorius, and in
+front of the semi-tendinosus, to be inserted into the upper part of the
+inner surface of the shaft of the tibia behind the sartorius and above
+the semi-tendinosus.
+
+Covered by the preceding muscles and placed more deeply, are the
+adductors, brevis and magnus, which fill up the space between the
+gracilis and the femur. The _adductor brevis_ extends from the pubis to
+the upper part of the linea aspera; the _adductor magnus_ is a thick,
+fleshy, triangular muscle which arises from the tuberosity and ramus
+of the ischium, and is inserted into the entire length of the linea
+aspera of the femur, so that its superior fibres are horizontal and
+its inferior fibres almost vertical in direction; among these last the
+most internal, which arise from the ischial tuberosity, form below a
+distinct tendon, which projects above the inner side of the knee-joint
+and is inserted into a tubercle (the _adductor_ tubercle of the femur)
+placed above the inner condyle of the femur.
+
+  [Illustration: FIG. 83.
+
+   HAMSTRING MUSCLES. 1, gluteus medius;--2, gluteus maximus;--3,
+   vastus externus;--4, biceps (long head)--5, biceps (short
+   head)--6, semi-tendinosus;--7, semi-membranosus;--8,
+   gracilis;--9, adductor magnus;--10, sartorius;--11, popliteal
+   space;--12, gastrocnemius.]
+
+The action of all the muscles which we have just studied, except the
+pectineus, is to draw the thigh inwards towards the axis of the body;
+they also bring the knees close to each other, hence they are called
+the adductors of the thigh.
+
+IV. _The back of the thigh._ The _posterior_ muscles of the thigh
+(_hamstring muscles_).--These muscles, three in number, arise from
+the tuberosity of the ischium, and thus their origins are hidden
+beneath the gluteus maximus. They emerge below the lower border of
+that muscle and descend vertically; above the posterior surface of the
+knee (or ham) they divide into two masses, one, the external, formed
+by a single muscle, the _biceps femoris_, the other internal, formed
+by two muscles placed one on the other, the _semi-tendinosus_ and the
+_semi-membranosus_.
+
+The _biceps femoris_ (4, Fig. 83) is so called because, like the biceps
+in the arm, it is formed above by two heads, a _long_ head which arises
+from the tuberosity of the ischium, and a _short_ head, more deeply
+placed, which arises from the linea aspera of the femur. These two
+heads unite in a stout tendon (12, Fig. 82) which the muscular fibres
+accompany for the greater part of its length, and which is directed
+downwards on the outer side of the knee, to be inserted into the summit
+of the superior extremity of the head of the fibula. This muscle flexes
+the leg on the thigh, and when it accomplishes this action its tendon
+becomes very prominent, forming the outer boundary of the region of the
+ham or popliteal space.
+
+The _semi-tendinosus_ (13, Fig. 82; 6, Fig. 83), visible throughout
+its entire extent (except at its origin, which is hidden beneath the
+gluteus maximus), has been so called because in a great part of its
+length, almost equal to its lower half, it is represented only by
+its tendon. It arises above from the ischium, and descends parallel
+to the long head of the biceps, to the inner side of which it is
+situated; towards the junction of the middle with the lower third
+of the posterior surface of the thigh, its fleshy belly becomes
+narrower, and is replaced by a long, thin tendon (13, Fig. 82) which
+inclines inwards, and passes behind the internal condyle of the femur,
+describing a slight curve with its concavity forwards behind the
+tendons of the sartorius and gracilis. With them (pages 258 and 264)
+it is inserted into the upper part of the internal surface of the
+shaft of the tibia (24, Fig. 86). This muscle flexes the leg, and in
+this movement the prominence of its tendon starts out as the internal
+boundary of the region of the ham.
+
+The _semi-membranosus_ is broader than the semi-tendinosus (7, Fig.
+83). It is situated beneath it and projects beyond it on both sides.
+It is so called because its upper half is formed by a broad membranous
+tendon arising from the tuberosity of the ischium. The muscular fibres
+commence below the middle of the thigh and form a large fleshy belly,
+thick, broad, and short, which passes into a strong tendon (14,
+Fig. 82) inserted mainly into the posterior surface of the internal
+tuberosity of the tibia.
+
+The fleshy belly of this muscle projects beyond the tendon of the
+semi-tendinosus on each side, and reaches to the middle line of the
+posterior surface of the thigh and knee, forming a large muscular
+prominence. When the leg is flexed on the thigh, the tendons of
+the biceps and semi-tendinosus become prominent, bounding a deep
+pit (the ham or popliteal space) corresponding to the upper part
+of the posterior surface of the knee, and the fleshy part of the
+semi-membranosus remains hidden in the bottom of this pit; but
+when the leg is extended on the thigh there is no longer a hollow,
+but the posterior surface of the knee presents, on the contrary, a
+prominent form, produced in the upper part by the fleshy mass of the
+semi-membranosus, and in the lower part by the muscles of the calf, to
+be described in the next chapter.
+
+
+
+
+                            CHAPTER XXIII.
+
+                     MUSCLES OF THE LEG AND FOOT.
+
+   General arrangement of the muscles with regard to the
+   skeleton.--Anterior muscles of the leg (_tibialis anticus_ and
+   _extensors_).--External or _peroneal_ muscles; relations of the
+   peroneus longus with the sole of the foot; its influence on the
+   form of the foot.--Posterior muscles; _gastrocnemius_ (details
+   of its composition and form). _Soleus_ muscle, _plantaris_,
+   _tendo Achillis_.--Muscles of the foot; 1st, dorsum of foot
+   (_extensor brevis_ muscle); 2nd, muscles of the sole of the foot.
+
+
+_Muscles of the leg._--The arrangement of the skeleton of the leg
+(tibia and fibula) is such that we might expect _a priori_ to find
+four muscular masses, one on each of the surfaces of the skeleton,
+but as the internal surface of the tibia is subcutaneous (2, Fig.
+84), is not covered by any muscle, and is overlapped by the anterior
+and posterior fleshy masses, it forms a long flat surface, slightly
+hollowed, extending from the inner side of the knee to the internal
+malleolus. The leg, therefore, presents for our study only three groups
+of muscles, occupying respectively the anterior or antero-external, the
+external or peroneal, and the posterior regions of the limb.
+
+I. _Anterior muscles_ (Fig. 84).--Arranged in the space which separates
+the fibula from the tibia, the muscles on the front of the leg are
+three in number, called, from within outwards, the _tibialis anticus_,
+the _extensor proprius hallucis_, and the _extensor longus digitorum_.
+
+The _tibialis anticus_ (3, Fig. 84) arises from the external surface
+of the tibia, and from the deep fascia over it (page 146), and
+descends obliquely downwards and inwards in the form of a prismatic
+or fusiform fleshy mass, of which the lower end gradually narrows, to
+be replaced by a strong tendon in the lower third of the leg. This
+tendon, inclining more and more to the inner side (2, Fig. 86), passes
+obliquely over the anterior surface of the lower end of the tibia, in
+front of the internal malleolus. It glides beneath the anterior annular
+ligament of the ankle, and reaches the inner part of the dorsum of the
+foot (3, Fig. 86), where it is inserted into the internal cuneiform,
+and the base of the first metatarsal bone. It flexes the foot on the
+leg, and inverts it, since it draws the dorsal surface of the foot
+towards the anterior surface of the leg, while at the same time it
+turns the foot inwards, and slightly raises its inner border. This
+muscle, during contraction, shows externally all the details of its
+shape--in the leg a fleshy mass which slightly overlaps the anterior
+border of the tibia or shin, and in front of the ankle an oblique cord
+marking clearly the direction of the tendon.
+
+The _extensor proprius hallucis_ (5, Fig. 84) is concealed at its
+origin between the tibialis anticus and the extensor longus digitorum.
+Only its tendon appears superficially (2, Fig. 85) in the lower third
+of the front of the leg, on the outer side of the tendon of the
+tibialis anticus. It passes beneath the annular ligament of the ankle
+and along the inner part of the dorsal surface of the foot (4, Fig.
+86), to be inserted into the base of the terminal phalanx of the great
+toe. When the great toe is forcibly turned up during extension this
+tendon is clearly shown throughout its entire course. In a normal foot
+this tendon occupies a straight line from the middle of the ankle-joint
+to the great toe, and the inner border of the foot and great toe should
+be parallel to it. In other words, the great toe should be in a line
+with the inner border of the foot (Fig. 52, page 151).
+
+  [Illustration: FIG. 84.
+
+   MUSCLES OF THE ANTERIOR REGION OF THE LEG.--1, tendon of the
+   rectus femoris;--2, tibia;--3, the anterior tibial muscle;--4,
+   the long extensor of the toes;--5, the proper extensor of
+   the great toe;--6, the peroneus tertius;--7 and 8, the
+   peroneus longus and brevis;--9, the external head of the
+   gastrocnemius;--10, the internal head of the gastrocnemius;--11,
+   extensor brevis digitorum;--12, the superior annular ligament of
+   the dorsum of the foot.]
+
+The _extensor longus digitorum_ (4, Fig. 84) arises from the external
+tuberosity of the tibia, on the outer side of the tibialis anticus,
+and from the upper three-fourths of the anterior surface of the
+fibula. It descends vertically, and terminates in a tendon divided
+into slips, which remain associated together (3, Fig. 85) to pass
+beneath the anterior annular ligament. Immediately afterwards, these
+slips spread out like a fan (4, Fig. 85) in the form of four tendons,
+which pass over the dorsum of the foot to be inserted into the second
+and third phalanges of the four outer toes. Each tendon behaves like
+the corresponding extensor tendon in the hand. It forms a membranous
+expansion on the dorsum of the first phalanx, joined by the tendons of
+the extensor brevis digitorum, lumbricals, and interossei muscles, and
+completes the capsule of the meta-tarso-phalangeal joint. Thereafter
+each tendon splits into three parts--one central and two lateral. The
+central slip is inserted into the intermediate phalanx, and the two
+lateral slips, reunited, are attached to the base of the terminal
+phalanx. Associated with the extensor longus digitorum is the _peroneus
+tertius_, an essentially human muscle, which has a common origin with
+the long extensor. Its tendon accompanies those of the last-named
+muscle beneath the annular ligament, and is directed outwards on
+the dorsum of the foot, to be inserted into the base of the fifth
+metatarsal bone. With the tibialis anticus the long extensor of the
+toes and peroneus tertius flex the foot on the leg, while at the same
+time the common extensor extends the toes on the foot. In this action
+it shows the prominence of its fleshy belly especially at the middle
+of the leg, and the tendons on the back of the foot are raised up like
+diverging cords. The peroneus tertius raises the outer border of the
+foot in such movements as skating and dancing, and it is only then that
+its prominence shows beneath the skin. Usually it is but little marked.
+
+  [Illustration: FIG. 85.
+
+   MUSCLES OF THE LEG (external surface).--1, 1, the anterior
+   tibial muscle;--2, 2, the tendon of the extensor proprius
+   hallucis;--3, 3, the extensor longus digitorum with its
+   tendons (4, 5, and 6);--7, the peroneus longus and its tendon
+   (8);--9, peroneus brevis and its tendon (10);--11, the external
+   head of the gastrocnemius;--12, 12, the soleus;--13, tendo
+   Achillis;--14, extensor brevis digitorum;--15, abductor minimi
+   digiti;--16, the rectus femoris;--17, 18, vastus externus;--19,
+   tendon of the biceps femoris;--20, external lateral ligament of
+   the knee.]
+
+II. _External muscles_ (Fig. 85).--These are two in number, placed on
+the outer side of the fibula, and called the _peroneal muscles_. They
+are distinguished as the peroneus longus and peroneus brevis. They
+completely cover the outer surface of the fibula, the peroneus longus
+arising from the upper two-thirds, the peroneus brevis from the lower
+two-thirds of the bone. The peroneus longus is behind and above, the
+peroneus brevis in front and below. Their tendons descend together and
+pass beneath the external annular ligament; that of the peroneus brevis
+lying next the bone and grooving the back of the external malleolus.
+Winding round the malleolus as on a pulley, they are directed forwards
+on to the outer border of the foot. Then only the tendons separate from
+each other, to be inserted into the foot at two points diametrically
+opposite. One (that of the peroneus brevis) is directed horizontally
+forwards, on the outer surface of the foot (10, Fig. 85), to be
+inserted into the base or posterior extremity of the fifth metatarsal
+bone; while the other, that of the peroneus longus, is directed
+obliquely forwards and downwards so as to reach the sole of the foot,
+beneath which it passes, lying in the groove of the cuboid bone; it
+then runs obliquely across the sole of the foot, from the outer towards
+the inner border, deeply hidden by the plantar muscles and ligaments,
+and is finally inserted into the posterior extremity of the first
+metatarsal bone and the under surface of the internal cuneiform bone.
+
+These two muscles, but especially the peroneus brevis, extend and turn
+the foot outwards, while at the same time they raise its external
+border; so that their action is the reverse of that of the tibialis
+anticus. But the peroneus longus has another important function which
+explains why the muscle becomes prominent whenever a particular effort
+is demanded of the foot, as, for example, when it is carried forward in
+dancing, or in the act of imparting motion to an object. This muscle,
+owing to the arrangement of its tendon, which passes like the string
+of a bow across the hollow of the sole of the foot, acts by deepening
+this hollow; it therefore raises the plantar arch, marked on the dorsal
+surface by an increase of the curve of the foot.
+
+III. _Posterior muscles_ (Figs. 82, 87).--The back of the leg is thick
+and fleshy, and is formed by numerous and powerful muscles, divided
+into two groups: the superficial group, which we shall describe in
+detail, and the deep group, for which a few words will be sufficient.
+
+The superficial group is formed by the _gastrocnemius_, _plantaris_,
+and _soleus_ muscles.
+
+The _gastrocnemius_ muscle (γαδτήρ, belly; κυήμη, leg) is responsible
+for the surface form of the prominence of the calf. It consists of two
+large, fleshy masses known as the inner and outer heads, which arise
+respectively from the upper part of the inner and outer condyles of
+the femur on their outer aspect. Overlapped by the insertions of the
+hamstring muscles, the two heads of the gastrocnemius form the lower
+boundaries of the popliteal space. They converge at its lower angle to
+be inserted (separately) into a broad membranous tendon, which forms
+the beginning of the _tendo Achillis_ (6, Fig. 87). At their origins,
+each head possesses a tendon which covers its superficial surface. At
+the insertion the tendon passes upwards for a considerable distance
+on their deep surfaces. At its insertion into the tendo Achillis,
+each fleshy head presents a rounded lower border; and it is to be
+particularly noted that the inner head of the muscle usually descends
+to a level lower than that of the outer head.
+
+  [Illustration: FIG. 86.
+
+   MUSCLES OF THE LEG (internal surface).--1, tibialis anticus;--2
+   and 3, its tendon;--4, tendon of the extensor proprius
+   hallucis;--5 and 6, internal head of the gastrocnemius;--7,
+   soleus;--8, tendo Achillis;--9, its attachment to the os
+   calcis;--10, tendon of the plantaris muscle;--11 and 12,
+   tendon of the tibialis posticus;--13 and 14, tendon of
+   the flexor longus digitorum;--15, tendon of the flexor
+   longus hallucis;--16, 16, abductor hallucis;--17, vastus
+   internus;--18, 19, 20, sartorius;--21, 22, gracilis;--23,
+   semi-membranosus;--24, semi-tendinosus.]
+
+This muscle bends the knee and extends the foot on the leg. Through
+the tendo Achillis it acts on the calcaneum or bone of the heel so
+as to raise the heel and cause the living model, if erect, to rise
+on the toes. Now the constitution of the muscle is such that its
+external form is quite different when it is in repose and when it is
+in contraction. Each head of the muscle, as already stated, possesses
+at its origin a membranous tendon, which expands over the outer part
+of the surface, but the inner part of each belly is fleshy. In a state
+of repose the two halves of the muscle unite in the same rounded and
+prominent shape, so that we cannot distinguish the part covered by the
+aponeurotic expansion of tendon from the part formed by free muscular
+fibres. But when the living model rises on the balls of the toes, or in
+any other movement produced by a powerful contraction of the muscle,
+we see the free fleshy part of each head swell up more strongly than
+the part covered and tied down by the aponeurosis. At that moment,
+therefore, the whole convex form of the calf presents a slight ovoid
+surface on each side, and a long vertical prominence in the middle
+line. This prominence is produced by the mesial muscular parts of the
+two heads of the muscle, which approach each other during contraction,
+and unite their double mass in a single median prominence. Fig. 82, by
+the differences in shading, enables us to distinguish the aponeurotic
+from the muscular parts, and to observe the important details of shape
+into the study of which we have entered. The clear or aponeurotic
+parts correspond to the two flat surfaces already mentioned, and the
+shaded or fleshy parts correspond to the median prominence, with this
+difference, that in the calf in contraction, this median prominence is
+smoother than in Fig. 82, the two halves which compose it being merged
+into a single mass, except at the angular space above the point where
+they bound the popliteal space.
+
+We will now return to what we have already said (see page 267) relative
+to the posterior region of the knee, examined in the living model in
+extension of the leg. If the model rises on the balls of the toes it is
+no longer possible to speak of the popliteal space as _a hollow_
+at the back of the knee. Under these conditions, the prominences
+(already studied) of the biceps, semi-membranosus, and gastrocnemius
+almost join each other, and the plantaris muscle, of which we will
+speak immediately, helps to fill up the space; the region of the
+popliteal space forms in reality a prominence, and the posterior
+surface of the knee is marked in its central portion by a strong
+muscular projection of which it is not possible to understand the cause
+except by an attentive study of the muscles named.
+
+The _soleus_ muscle, so called because its form has been compared to
+that of a _sole_ (Latin--_solea_), is placed beneath the gastrocnemius,
+which overlaps it, more on the inner (7, Fig. 86) than on the outer
+border (12, Fig. 85) of the calf. In its action it is simple. It only
+acts on the ankle-joint, as a powerful extensor of the foot. Arising
+from the back of the fibula and from the tibia, its fibres are inserted
+below into the deep surface of the tendo Achillis to within two inches
+of the heel.
+
+The _tendo Achillis_ is a strong band of fibrous tissue occupying
+the lower part of the back of the leg. Membranous above, where it
+is continued upwards on the deep surface of the bellies of the
+gastrocnemius muscle, it becomes narrower and thicker below as it
+approaches the heel. Broadening out slightly at its lower end, it
+is inserted into the inferior half of the posterior surface of the
+calcaneum, forming the prominence of the heel. In a muscular leg the
+fibres of the soleus may be shown superficially, bulging beyond the
+tendo Achillis at its outer and inner borders, below the outline of the
+gastrocnemius, and more on the outer than on the inner side (5, Fig.
+82, page 263).
+
+The _plantaris_ is a small, insignificant muscle of which the fleshy
+origin (6, Fig. 82) is from the outer condyle of the femur, under
+cover of the outer head of the gastrocnemius muscle. Its small fleshy
+belly is succeeded by a long, thin tendon (7, Fig. 82), which descends
+obliquely between the gastrocnemius and the soleus to reach the inner
+border of the tendo Achillis, along which it descends (10, Fig. 86).
+Sometimes it is united with this tendon early in its course, and
+sometimes it reaches the calcaneum, or it may join the internal annular
+ligament at the ankle.
+
+The deep muscles of the back of the leg are not visible on the model
+except on the inner side above the ankle. Here, on the inner side
+of the tendo Achillis (8, Fig. 82), is placed a series of tendons,
+proceeding in the interval between the internal malleolus and the
+calcaneum to the foot. The muscles are the _tibialis posticus_, the
+_flexor longus digitorum_, and the _flexor longus hallucis_. The
+fleshy bellies of these muscles, deeply hidden beneath the superficial
+muscles, arise from the posterior surface of the tibia, from the
+fibula, and from the interosseous membrane. Their tendons descend
+obliquely over the back of the internal malleolus, where those of the
+tibialis posticus and the common flexor of the toes alone are visible
+(the tendon of the flexor proprius hallucis being almost entirely
+hidden beneath the tendo Achillis). From this they are reflected over
+the internal malleolus and pass into the sole of the foot, bound down
+on the inner side of the ankle by the dense band of the _internal
+annular ligament_. The tibialis posticus is almost immediately
+inserted by radiating bands into most of the tarsal and metatarsal
+bones (12, Fig. 86), and the other two tendons reach the toes, where
+they are inserted in the same manner as we have already described for
+the tendons of the flexor longus pollicis and the deep flexor of the
+fingers in the hand.
+
+  [Illustration: FIG. 87.
+
+   THE MUSCLES OF THE CALF.--1, biceps;--2, semi-tendinosus;--3,
+   popliteal space;--4, gastrocnemius;--5, 5, soleus;--6, tendo
+   Achillis;--7, os calcis;--8, peroneus longus;--9, tibialis
+   posticus and flexor longus digitorum.]
+
+_MUSCLES OF THE FOOT._--The muscles of the foot include not only the
+muscles of the plantar region, corresponding to the palm of the hand,
+but also the tendons on the dorsum of the foot, and a special extensor
+muscle, the _extensor brevis digitorum_.
+
+The tendons of muscles on the dorsum of the foot have already been
+described (p. 270). The _extensor brevis digitorum_ muscle (11,
+Fig. 84, and 14, Fig. 85) consists of a short, fleshy belly placed
+obliquely on the dorsum of the foot, and extending from behind inwards
+and forwards. It origin is rounded and attached to the upper surface
+of the calcaneum in the _cavity or canal of the tarsus_ (page 155),
+external to the astragalus. From this origin it is directed forwards
+and inwards; becoming broader, it passes beneath the tendons of the
+common extensor and immediately divides into four muscular slips,
+each of which has a tendon attached to it. These tendons pass under
+those of the common extensor, so as to form with them a figure with
+lozenge-shaped spaces, and proceed to the four inner toes to be
+inserted, in the case of the great toe, into the base of the first
+phalanx; uniting, in the case of the second, third, and fourth toes,
+with the expansions of the extensor tendons on the dorsum of the
+phalanges. This muscle aids in the extension of the toes, and by
+its obliquity counteracts the action of the long extensor. When it
+contracts, the portion of the muscle situated on the outer side of
+the tendons of the long extensor become very prominent, not being
+tied down by anything, and this prominence is still clearer because
+behind it is a depression, more or less evident, corresponding to the
+calcaneo-astragaloid cavity of the tarsus.
+
+We will not describe at length the muscles of the sole of the foot with
+regard to form. The foot derives most of its characteristics from its
+bony structure; the muscles of the sole round off by their presence
+the angles of the skeleton and fill up the cavities, but do not modify
+essentially the bony forms. On the other hand, these numerous muscles
+are in general but poorly developed, and they are to a large extent
+united into common masses, which makes it difficult, except for the
+skilled anatomist, to isolate and recognise distinctly each fleshy
+belly. It is therefore useless for an artist to enter into a detailed
+study of these muscles, which reproduce in their general arrangement
+the distribution of the muscles of the hand. We will content ourselves,
+then, by saying that the sole of the foot, like the palm of the hand,
+possesses three muscular masses--1st. An internal group (16, Fig.
+86), belonging to the great toe, formed by the _abductor hallucis_,
+which arises from the calcaneum, and by the _flexor brevis_, the
+_adductor transversus_, and _adductor obliquus hallucis_, which arise
+from the anterior bones of the tarsus and from the metatarsus; 2nd.
+An external group (15, Fig. 86), belonging to the little toe, formed
+by the _abductor_, which arises from the calcaneum, and the _flexor
+brevis_, from the cuboid; 3rd. Finally, a central mass, formed by the
+_flexor brevis digitorum_, the _long flexor tendons_, _lumbricals_, and
+_interossei_--which in a sense repeat what we have said regarding the
+muscles of the same name, more easily studied, in the hand.
+
+
+
+
+                             CHAPTER XXIV.
+
+                         MUSCLES OF THE NECK.
+
+   Lateral and anterior regions of the neck.--_Sterno-mastoid_
+   muscles. The anterior triangle; infra-hyoid and
+   supra-hyoid regions.--Organs contained in the neck
+   (vertebral column, œsophagus, and trachea).--Infra-hyoid
+   muscles--_omo-hyoid_, _sterno-hyoid_, _sterno-thyroid_, and
+   _thyro-hyoid_.--Supra-hyoid muscles--_digastric_, _stylo-hyoid_,
+   and _mylo-hyoid_.
+
+
+_Muscles of the neck._--We have already, in treating of the trapezius,
+studied the muscular structure and form of the posterior region of
+the neck, and the details have been described of the upper part of
+the side of the neck, and the oblique longitudinal groove between
+the anterior border of the trapezius and the posterior border of the
+sterno-cleido-mastoid (pages 208 and 210). It now remains to examine
+the inferior part of this groove and all the anterior region of the
+neck. This study should begin with that of the sterno-cleido-mastoid
+muscles, which have the most important influence on the form of this
+region, and which by their direction map out on the anterior surface of
+the neck a muscular interval or space in which it will be easy to study
+the deeply placed muscles.
+
+The _sterno-cleido-mastoid muscles_ are two in number, one on each side
+of the neck, extending from the upper limit of the thorax, obliquely
+upwards and backwards, to the base of the skull (19, Fig. 88). The
+muscle arises below by two heads--one internal or sternal, which
+arises by a strong tendon from the front of the first piece of the
+sternum (18, Fig. 70, page 197), the other external or clavicular,
+which arises in the form of a thin fleshy band from the inner third of
+the upper surface of the clavicle, above the origin of the clavicular
+portion of the great pectoral muscle (Fig. 68, page 194). These
+two heads are directed upwards and backwards, separated at first
+by a narrow triangular space, of which the base corresponds to the
+sterno-clavicular joint (Fig. 68); they then unite to form a single
+muscle, broad and thick, which ascends obliquely towards the skull,
+passing behind the angle of the lower jaw and the ear to be inserted
+into the surface of the mastoid process of the temporal bone and the
+superior curved line of the occipital bone (16, Fig. 73).
+
+This muscle, being inserted into the skull at a point which is situated
+behind the axis of the movements of flexion and extension of the head,
+acts by extending the head on the neck, but to this movement, usually
+little marked, it adds the power of flexing the neck on the trunk. When
+both these muscles contract at the same time, they produce extension of
+the head on the neck and flexion of the neck on the thorax; therefore
+we see both clearly marked beneath the skin in a person lying down
+who raises his head (by flexion of the neck). When one muscle only
+contracts, it turns the face to the opposite side; therefore in the
+living model whose face is turned to the right the face turns to this
+side by the contraction of the left sterno-cleido-mastoid muscle, of
+which the prominence is well shown beneath the skin as a broad band,
+passing from the sternum to the mastoid process of the temporal bone.
+There are various attitudes in which this prominence is particularly
+remarkable, as when we carry the head quickly to one side to answer a
+question or give an order; or in the act of listening intently, when
+we concentrate our attention to one side and extend the head a little,
+turning the region of the ear upwards and forwards, an attitude in
+which the sterno-mastoid becomes particularly prominent beneath the
+skin of the neck.
+
+From their insertions and direction we see that these two muscles
+are very close to each other below and wide apart above. Stretching
+diagonally across the side of the neck, each muscle forms the interval
+between two triangular spaces--the _posterior triangle_ behind,
+bounded by the sterno-mastoid, trapezius, and the clavicle (below);
+and the _anterior triangle_ in front, bounded by the sterno-mastoid,
+the middle line of the neck in front, and the lower jaw above. The
+anterior triangles of the two sides comprise together the space between
+the two sterno-cleido-mastoid muscles. This space is in the form of a
+triangle, with its apex below, corresponding to the episternal notch,
+and its base above, formed by the whole breadth of the lower jaw.
+This triangle is the anterior region of the neck, divided into two
+parts by the presence of the hyoid bone--a small bone without direct
+connection with the rest of the skeleton, and placed transversely above
+the prominence of the larynx (23, Fig. 88). The lower part forms a
+vertical plane, oblique downwards and backwards, and sinking behind
+the sternum; this is the infra-hyoid region, containing the infra-hyoid
+muscles. The upper part of the area forms a plane approaching more or
+less the horizontal, proceeding from the hyoid bone to the chin and the
+circumference of the lower jaw; this is the supra-hyoid region, or that
+of the chin, containing the supra-hyoid muscles.
+
+Before entering further into the description of these regions we
+must point out the presence of several organs which, placed in front
+of the vertebral column, project forwards in the space between the
+sterno-mastoid muscles. In the middle line of the neck, the region
+above the hyoid bone corresponds to the floor of the mouth, in which
+the tongue lies, having on each side large salivary glands partly
+concealed by the lower jaw; below the depression corresponding to the
+hyoid bone appear the cartilages of the larynx--the thyroid (pomum
+Adami), projecting forwards, and more marked in the male than in the
+female, and the cricoid cartilage, to which the windpipe or trachea is
+attached. Separating the tongue and larynx from the vertebral column
+is the cavity of the pharynx, which is continuous below the cricoid
+cartilage, with the gullet or œsophagus, situated behind the windpipe
+or trachea. The œsophagus is soft and fleshy, with a cavity effaced
+when empty. The _trachea_, which on account of its functions is always
+open, is formed of incomplete cartilaginous rings, which give it an
+almost cylindrical form and render it prominent below in the middle
+line of the neck. Crossing the upper part of the trachea is the median
+part of a gland known as the _thyroid body_, which in some cases
+(especially in the female) may form a slight rounded projection in the
+infra-hyoid region of the neck.
+
+  [Illustration: FIG. 88.
+
+   MUSCLES OF THE NECK AND FACE.--1, frontal;--2, occipital;--3,
+   aponeurosis of the occipito-frontalis;--4, temporal;--6,
+   orbicularis palpebrarum;--7, levator labii superioris et alæ
+   nasi;--8, dilator naris anterior and posterior;--9, compressor
+   naris;--9′, pyramidalis nasi;--10, zygomaticus minor;--11,
+   zygomaticus major;--12, masseter;--13, levator anguli oris;--14,
+   levator labii superioris;--15, orbicularis oris;--16,
+   buccinator;--16′, depressor anguli oris, or triangularis
+   oris;--17, depressor labii inferioris, or quadratus menti;--19,
+   sterno-cleido-mastoid;--20, trapezius;--21, digastric and
+   stylo-hyoid;--22, anterior belly of the digastric;--24,
+   omo-hyoid;--25, sterno-hyoid;--26, thyro-hyoid;--27,
+   mylo-hyoid;--28, 29, splenius.]
+
+The _infra-hyoid muscles_ ascend from the back of the sternum, inside
+the thorax, towards the lower border of the hyoid bone. They are four
+in number--two superficial (the omo-hyoid and sterno-hyoid) and two
+deep (the sterno-thyroid and thyro-hyoid).
+
+The _omo-hyoid_ (24, Fig. 88; 17, 18, Fig. 89) is a small muscle, long
+and slender, with a very remarkable course. It consists of two fleshy
+bellies with an intermediate tendon. It arises from the upper border
+of the scapula near the root of the coracoid process, and is directed
+at first obliquely forwards and inwards behind the clavicle; after
+crossing the posterior triangle it turns on itself, and is directed
+upwards beneath the sterno-mastoid and through the anterior triangle
+to be inserted into the lateral part of the lower border of the hyoid
+bone. This muscle, covered at first by the trapezius and then by the
+sterno-mastoid, is thus visible on the model in only two parts of
+its course--in front of the sterno-mastoid, where its anterior belly
+appears over the trachea, and again in the posterior triangle, where
+its posterior belly occupies the lower portion of the groove which
+separates the trapezius from the sterno-mastoid. Although deeply
+placed, this muscle becomes visible beneath the skin, for it is brought
+into sharp relief during certain actions. Evidently, from its slender
+form, we cannot expect it to be an important elevator of the scapula;
+but it serves to depress the hyoid bone. The most important function
+of the muscle is by its contraction, especially during spasmodic
+efforts in respiration, as in the strong inspiration in sighing or
+sobbing; in such cases it prevents the skin and loose aponeurotic
+tissue from being too strongly depressed in the supra-clavicular fossa
+by atmospheric pressure. Therefore, if the neck is thin and the fossa
+well marked, as in an aged female, during the movements of sobbing or
+abrupt respiration a cord corresponding to the posterior belly of the
+omo-hyoid muscle may be clearly seen in the supra-clavicular fossa.
+
+The _sterno-hyoid_ (25, Fig, 88; 14, Fig. 89) forms a long, thin,
+fleshy band, extending from the back of the sternum and clavicle
+upwards to the lower border of the hyoid bone. Both these muscles are
+contiguous to each other by their internal borders above, but below, at
+the deep median fossa corresponding to the episternal notch, they are
+separated by a narrow angular space, in which appear the trachea and
+the inner border of the sterno-thyroid muscle.
+
+The two deep muscles of this region (the sterno-thyroid and
+thyro-hyoid) are continuous with one another. They lie beneath the
+sterno-hyoid and omo-hyoid muscles, and cover the trachea and larynx
+in the front of the neck. The _sterno-thyroid_ muscle arises from
+the posterior part of the first piece of the sternum, and ascends
+vertically beneath the sterno-hyoid. It appears at the inner border
+of the sterno-hyoid at the lower part of the neck on each side of the
+middle line (Fig. 68); reaching the thyroid cartilage, it is inserted
+into an oblique line on its external surface. The thyro-hyoid muscle
+arising from this oblique line on the thyroid cartilage ascends to be
+inserted into the hyoid bone.
+
+  [Illustration: FIG. 89.
+
+   THE MUSCLES OF THE NECK.--1, digastric (posterior belly);--2,
+   digastric (anterior belly);--3, hyoid bone;--4, stylo-hyoid;--5,
+   mylo-hyoid;--6, genio-hyoid;--7, stylo-glossus;--8,
+   hyo-glossus;--9, internal pterygoid;--10, stylo-pharyngeus;--11,
+   sterno-cleido-mastoid;--12, sterno-cleido-mastoid (sternal
+   head);--13, sterno-cleido-mastoid (clavicular head);--14,
+   sterno-hyoid;--15, sterno-thyroid;--16, thyro-hyoid;--17,
+   omo-hyoid (anterior belly);--18, omo-hyoid (posterior
+   belly);--19, trapezius;--20, clavicle;--21, scalenus posticus.]
+
+The _supra-hyoid muscles_ proceed from the hyoid bone to the base of
+the skull and lower jaw, and by their contraction elevate this bone,
+as can be easily observed in those who bring into action the pharynx
+or larynx, as in the act of singing or swallowing. The first of these
+supra-hyoid muscles is the _digastric muscle_, composed of two fleshy
+bellies connected together by an intermediate tendon (1, 2, Fig. 89).
+The _posterior belly_ connects the hyoid bone with the under-surface
+of the mastoid process; the anterior belly connects the hyoid bone
+to the lower border of the lower jaw near the chin. Next come two
+other muscles one behind, lying alongside the posterior belly of the
+digastric, and called the _stylo-hyoid_ (4, Fig. 89), and another
+in front, called the _mylo-hyoid_ (5, Fig. 89); this muscle lies
+underneath the anterior belly, and extends between the hyoid bone
+and the deep surface of the body of the lower jaw. It thus forms a
+partition closing in the floor of the mouth on each side of the tongue.
+
+The _digastric_ muscle arises from the under-surface of the mastoid
+process of the temporal bone. From this origin its fusiform posterior
+belly descends obliquely downwards and forwards, and near the hyoid
+bone is replaced by a round tendon. This tendon is attached by a
+fibrous pulley to the hyoid bone, and, taking its fixed point here, it
+turns abruptly, so as to be directed obliquely upwards and forwards
+towards the chin; at the same time this tendon is soon replaced by
+the anterior belly, also fusiform, which is inserted on the posterior
+surface of the symphysis of the chin, into a small depression called
+the digastric fossa. We see that this muscle, with its two bellies, is
+admirably arranged to raise the hyoid bone, and consequently the whole
+of the larynx; for the anterior belly carries the hyoid bone upwards
+and forwards, the other upwards and backwards, and if the two contract
+at the same time they will raise the hyoid bone directly upwards.
+
+The _stylo-hyoid_ is a small muscular fasciculus which accompanies
+the posterior belly of the digastric (21, Fig. 88). Arising from the
+styloid process of the temporal bone, this muscle passes downwards and
+forwards beneath the posterior belly of the digastric, with which it
+is closely connected; at the level of the hyoid bone the tendon of the
+digastric pierces the stylo-hyoid, and the latter terminates by an
+aponeurotic slip which is inserted into the lateral part of the hyoid
+bone. On the model the stylo-hyoid and digastric are united in one
+cylindrical bundle (Fig. 88).
+
+The _mylo-hyoid_ muscle (27, Fig. 88) forms the floor of the cavity
+of the mouth. It constitutes a quadrilateral fleshy plane, attached
+by its upper border to the inner surface of the body of the lower jaw
+in a prominent oblique line; by its inferior border it is inserted
+into the hyoid bone. Above the hyoid bone the mylo-hyoid muscles are
+also inserted in the middle line into a fibrous raphe, so that the two
+muscles, that of the right and left side, form practically a single
+layer constituting the floor of the mouth. This muscle is covered
+on its deep surface by the mucous membrane of the mouth and by the
+fleshy fibres of muscles which are not visible externally, and which,
+arising from the small tubercles developed on the posterior surface of
+the symphysis of the chin (_genial tubercles_), are inserted either
+into the hyoid bone (_genio-hyoid_) (6, Fig. 89) or into the tongue
+(_genio-hyo-glossus_). The mylo-hyoid muscles, like the previous
+muscles, assist in raising the hyoid bone and larynx; it is to be
+noted, too, that the supra-hyoid muscles also act in depressing the
+lower jaw and opening the mouth.
+
+
+
+
+                             CHAPTER XXV.
+
+                         MUSCLES OF THE HEAD.
+
+   1st. Muscles of _mastication_; _masseter_, its form, its share
+   in the physiognomy (character of firmness, of violence);
+   _temporal muscle_. 2nd. Muscles of expression; nature and
+   special mechanism of the muscles of the _skin_; object
+   of their study (expression of actual passion, momentary
+   and not characteristic of the subject).--History of the
+   question.--Leonardo da Vinci, Le Brun, Camper, Charles Bell,
+   Lavater, Sue, Humbert de Superville.--Particular interest of
+   the drawings given by Humbert de Superville (“Unknown Signs of
+   Art”).--Duchenne of Boulogne and the experimental method applied
+   to the study of physiognomy.--Darwin (physiognomy from the
+   philosophical point of view, and evolution).
+
+
+The muscles of the head with few exceptions occupy the anterior region
+of the head and more particularly the _face_. They are divided into two
+very distinct classes--1st, the muscles which serve for _mastication_
+and move the lower jaw; and 2nd, the muscles which, under the influence
+of emotion, modify the traits of the countenance and serve for the
+expression of the emotions. We call these the _muscles of expression_.
+
+The muscles of mastication present the general arrangement that we have
+already met with in the various muscles of the trunk and limbs. They
+are attached to the bones, and they have fleshy bellies, more or less
+thick, which swell up in contraction, and are marked by prominences,
+just as the contraction of the biceps is shown by the prominence it
+produces on the anterior surface of the arm. The muscles of expression,
+on the contrary, present a different type. These are muscles of
+the _skin_, which move the skin and not the parts of the skeleton;
+therefore their fleshy parts are in general very slender, and their
+contraction is not marked by any local swelling corresponding to the
+fleshy body, but only by change in place and form of the folds and
+membranous structures of the face (eyelids, lips, etc.). We will first
+study the muscles of mastication.
+
+_Muscles of mastication._--The muscles which move the lower jaw are
+inserted into the ramus and angle of the bone. Those on the inner side
+of the jaw are the deeply placed _pterygoid_ muscles (so called because
+they arise from the pterygoid process of the sphenoid bone). We need
+not dwell on these muscles here, for they are deeply hidden in the
+zygomatic fossa of the head, and are not visible in any part on the
+surface. Those on the outer side are inserted either into the ramus
+and angle of the bone (masseter muscle) or into the coronoid process
+(temporal muscle).
+
+The _masseter muscle_ is a quadrilateral fleshy mass (12, Fig. 88)
+of which the upper attachment arises from the zygomatic arch (Fig. 56),
+and the lower attachment is inserted into the ramus and angle of the
+jaw. The anterior border of this muscle is thick, and in thin subjects
+forms a prominence, in front of which the cheeks are sunk so as to
+produce a more or less marked depression. In contraction the masseter
+raises the lower jaw and brings it into contact with the upper, against
+which it presses strongly. It would be superfluous to dwell here on
+the part this muscle plays in mastication. It is more important to
+remark that during violent emotions, or even when we accomplish a
+powerful effort, we involuntarily clench the jaws. Contracting the
+masseter, therefore, in anger, menace, and in the strong expression
+which we characterise commonly by saying that the subject grinds
+his teeth, we see the masseter shown in the form of a quadrilateral
+prominence on the side of the face. Therefore the accentuation of
+the form of the masseter contributes to give to the physiognomy an
+energetic expression, and generally that of brute force.
+
+The _temporal muscle_ (4, Fig. 88) occupies the entire extent of the
+temporal fossa of the skull (Fig. 56); it arises from the bones that
+form that fossa and from an aponeurosis which, arising from the borders
+of the fossa, is attached to the upper border of the zygomatic arch,
+so as to form a species of cover (_temporal fascia_) to the fossa
+in question. From these multiple points of origin the fleshy fibres
+converge below and form a strong tendon which embraces the coronoid
+process of the inferior maxillary bone (25, Fig. 56), into which it is
+inserted. This muscle raises the lower jaw, but as it is shut up, so
+to speak, in a close space (temporal fossa and aponeurotic cover) it
+does not show during its contraction a remarkable prominence in the
+temporal region; nevertheless, in a person performing the movements
+of mastication we see the skin of the temple, above the zygomatic
+arch, slightly raised in a series of rhythmical movements; these
+movements alone show externally the contractions of this muscle during
+mastication.
+
+_Muscles of expression._--From what we have already said respecting
+the peculiar arrangement of these muscles of the skin, it is easy to
+understand that their study must be undertaken in a totally different
+manner from that of the muscles of the skeleton. We do not seek so much
+to define the form of the fleshy masses as to trace the direction along
+which each muscle exercises traction on the skin. Given the bony or
+cutaneous attachments of the muscle, we must observe the direction in
+which it acts, and so define the form of the folds or wrinkles which it
+causes on the skin, and ascertain what facial expression is acquired
+by these changes. Before we enter into these details, it is necessary
+to glance rapidly at the history of this particular question of human
+physiognomy, and then to consider the method by which its study should
+be undertaken.
+
+First we must remark that we study here, with regard to the muscles of
+the face, _physiognomy in a state of action_--namely, the characters
+that affect the features at a given moment, under the influence
+of a passionate movement which causes (it may be) the involuntary
+contraction of one of the numerous muscles of the skin. Indeed,
+we may almost assert that the muscles of the face might be given
+names associated with mental states--_attention_, _pain_, _menace_,
+_laughter_, _sorrow_, _contempt_, _disgust_, &c. But we cannot pretend
+to study physiognomy in a state of repose, or to learn by the normal
+and permanent accentuation of certain of these traits the character of
+the subject and the passions that most frequently disturb him.
+
+Doubtless, these two studies have numerous points in common; it is
+easy to admit that, in a subject who is governed by one prevailing or
+overpowering emotion, such as suspicion, grief, or pain, the permanent
+or frequently repeated contraction of the muscles which correspond to
+these emotions can definitely mould the character of the face, so as to
+leave imprinted on it in a permanent form the sentiments that govern
+the mind.
+
+But this analysis of the character of a subject is a very delicate
+study, always very uncertain, and admitting of philosophical
+developments which would carry us far away from the domain of anatomy.
+On the other hand, the determination of characteristic expressions
+impressed upon the face by the contraction of this or that muscle has,
+from the researches of Duchenne (of Boulogne), become a study which
+presents all the precision and certainty that we can claim from facts
+strictly deduced from anatomy.
+
+Before the researches of Duchenne, the majority of books written on
+expression dealt almost entirely with _physiognomy_, or the means of
+recognising the character by the study of the habitual state of the
+traits of the countenance. We shall, in the first place, mention the
+works of Le Brun, Camper, Lavater, C. Bell, Humbert de Superville, and
+Sue, and then we shall refer to the investigations of Duchenne and
+Darwin.
+
+Long ago, in the drawings of Leonardo da Vinci, we find some valuable
+indications of the state of the face and neck in the expression of
+the emotions. This great master, for example, clearly perceived the
+part that the platysma muscle of the neck takes in the expression
+of violent passions, and portrayed the transverse folds which then
+mark it beneath the chin. Le Brun, however, was the first to arrange
+studies of this character into a doctrinal series. The publications in
+which his views on this subject have been preserved are numerous.[7]
+The artist will find there a number of interesting observations,
+curious comparisons, and ingenious explanations. Le Brun occupied
+himself principally with the resemblance of certain types of human
+physiognomies to the heads of animals; in short, he studied physiognomy
+in relation to character.
+
+Camper, whose works we have already quoted respecting the facial angle
+(page 181), was an anatomist and an artist. He analysed the action of
+the facial muscles, and it was he who first laid down this general
+rule--viz. that the contraction of each muscle of the face produced in
+the skin one or more folds, of which the direction is always at right
+angles to that of the muscle, a precept that we shall find to be true
+with regard to almost every muscle of the face, and especially for the
+frontalis, the great zygomatic, &c. Besides the exact observations that
+the artist will meet in the works of Camper, he will find in addition
+an interesting historical account of the question.
+
+An English anatomist, Sir Charles Bell, celebrated for his studies
+of the nervous system, also analysed the expressions of the face.[8]
+But though his work affords picturesque descriptions and admirable
+illustrations, it is more interesting to the anatomist than the artist.
+
+The title of the work of Lavater (_The Art of Knowing Man by his
+Countenance_)[9] indicates the object sought by the author. We find
+in this work good illustrations, and curious observations especially
+applicable to the study of physiognomy, but frequently without order,
+without method, and accompanied by dissertations on whimsical subjects,
+such as the chapters devoted to _imaginations_ and _envies_, to _warts_
+and _beards_, and to _lines of animality_, &c.
+
+In order to have an idea of the manner in which, at this epoch, authors
+attempted the study of physiognomy, making this delicate analysis a
+pure affair of sentiment, it is sufficient to mention the work of Sue
+(_Physionomie des Corps Vivants, considéré depuis l’Homme jusqu’à la
+Plante._ Paris, 1797.) In the middle of a long affected treatise on
+physiognomy and its relation to the passions, this, for example, is
+how he expresses himself concerning the mouth:--“A mouth delicate and
+pure is perhaps one of the best recommendations. The beauty of the
+portal proclaims the dignity of that which passes through. Here also
+is the voice, the interpreter of the heart and mind, the expression
+of truth, friendship, and the most tender sentiments.” With regard to
+the incessant comparison of human physiognomy with that of animals,
+the author stops at nothing in this singular course, and speaks
+dogmatically on the physiognomy of fishes, serpents, grasshoppers, and
+intestinal worms (!), as well as that of man. “Many fishes,” said he,
+“are wanting in that which gives a character of amenity, kindness, and
+tenderness.” “The intestinal worms have a very decided physiognomy ...
+the character of their physiognomy inspires in man sorrow and awe.”
+
+Amidst the works of a more serious, though still empirical character,
+we must mention in particular one which, although dealing with the
+countenance only in a secondary degree, yet presents several valuable
+observations on this subject. We have endeavoured to utilise these
+investigations in the diagrammatic representation of the action of the
+muscles of the face. We speak of the treatise of Humbert de Superville
+(_Des Signes Inconscients de l’Art_, 1827). The author gives three
+drawings of the human face, in which the lines represent the eyes, the
+lower boundary of the nose, and the lips. In one of these drawings
+(Fig. 90) the lines are all horizontal, in the second (Fig. 91) they
+are all inclined downwards and outwards (from the median line), and
+in the third (Fig. 92) they are all inclined upwards and outwards.
+The author remarks that the first figure (with the lines horizontal)
+produces an impression of calmness, greatness, and constancy; and
+he adds that in the same way in nature and architecture horizontal
+lines give rise to the idea of calmness, stability, and grandeur: the
+cedar, with its horizontal branches, is of all the trees the one that
+realises this impression in the highest degree. On the contrary, the
+second figure (with the lines directed obliquely downwards) gives
+an impression of sadness, pain, and grief; and the author does not
+fail to compare the direction of the features of such a countenance
+with the direction of the architectural lines in tombs and funeral
+monuments, and that of the branches of the trees which everywhere are
+planted in preference to others in cemeteries, and whose branches
+always hang obliquely. Lastly, the third figure (with the lines
+obliquely upwards) gives rise to the impression of gaiety, laughter,
+levity, inconstancy; and, to continue the preceding comparison,
+everyone must acknowledge that Chinese architecture, with its lines
+oblique and diverging upwards and outwards, can never--at least, in the
+eyes of a European--produce an impression of grandeur and majesty.
+
+  [Illustration:
+
+    FIG. 90.      FIG. 91.      FIG. 92.
+
+   THE THREE FIGURES OF HUMBERT DE SUPERVILLE--(Fig. 90, calmness;
+   Fig. 91, sadness; Fig. 92, gaiety).]
+
+These figures, and the remarks that de Superville makes afterwards,
+but which we have not emphasised here, are strikingly exact, when
+we consider the features in the state of movement or in a momentary
+expression of emotion. All the muscles which take part in the
+expression of pain, sadness, and contempt help to incline the features
+obliquely downwards and outwards, some by acting on the outline of the
+eyes, others on that of the mouth, &c. On the contrary, the muscles
+of laughter, raising its angles, draw the mouth obliquely upwards
+and outwards, and--for certain reasons that we will analyse further
+on--seems to give a similar direction to the outline of the eyes. In
+a word, features, starting from the state of repose, represented by
+the first figure of Humbert de Superville (Fig. 90), oscillate in two
+opposite directions, either ascending, to express the scale of gaiety
+and laughter (in which the features are oblique upwards and outwards,
+Fig. 92), or descending--sadness, pain, and tears (in which the
+features are oblique downwards and outwards, Fig. 91). The exactness
+of the drawings furnished by Humbert de Superville for the general
+expression of the physiognomy induces us to try, by similar drawings,
+to represent the action of each muscle separately. Knowing the action
+of a muscle, and knowing from the photographs of Duchenne the direction
+that it imparts to a certain feature of the face, either to the line of
+the eyebrows, the opening of the eyelids, the nostrils, or the lips,
+we have indicated by a simple stroke or line these changes, either
+in direction or in the form of one of those lines, and have obtained
+theoretical figures sufficiently expressive to characterise the emotion
+geometrically, so to speak, in the manifestation of which this or that
+muscle is affected. Such are the Figures 96, 98, 100, 102, 103, 104,
+106 (page 317 and following), by means of which we will attempt to
+explain the action of each muscle of expression. We may say that these
+drawings, without any pretension, are, so to speak, the primer of the
+language of physiognomy.
+
+We now arrive at the history of the work of Duchenne, to which we
+owe all that follows. While all his predecessors had been taken up
+with observation, Duchenne introduced the experimental method into
+the study of physiognomy. His process, simple in conception, was very
+delicate in application. His method was to cause the contraction of
+each muscle _singly_, and that the expression that resulted might be
+appreciated not only at the moment of the experiment, but again at any
+time, and submitted to the judgment of all, he photographed the subject
+at the moment when the muscle was contracted. This last operation was
+easily accomplished, but the excitation of a single muscle was a more
+delicate operation. Everyone knows that by electricity, in placing
+the two electric needles (the two poles of the current) on the course
+of a muscle, we can cause the contraction of the muscle beneath the
+skin. But no subject would lend himself to this experiment. At first
+he tried on the dead body of an executed criminal a short time after
+death; but the muscles of the face lose their excitability two hours
+after death, and then it is only by actual exposure of the muscle and
+direct stimulation that we can obtain contraction by the application of
+electricity. On the other hand, if we attempt it on any living subject,
+we can, it is true, cause a muscle to contract by applying electricity
+over its site; but the electric current, traversing the skin to reach
+the muscle, at the same time that it excites the motor nerves of the
+muscle, excites also the sensory nerves of the skin and produces acute
+pain. From this fact we see that we produce on the face of the subject,
+not a simple and characteristic expression, but a true grimace, or an
+irregular contraction of all the muscles under the influence of the
+pain.
+
+Duchenne had the good fortune to be able to experiment on a subject in
+whom a particular infirmity rendered impossible the last inconvenience
+we have noted. This was an old pensioner of the hospital who had
+_anæsthesia_ of the face (ἀνα, absence of; αἴσθησις, sensibility),
+in whom the skin of the countenance was insensible to the most painful
+excitation; electricity could be applied to the skin without producing
+any painful reaction, and yet excited the muscles beneath, which had
+perfectly preserved their contractility, and performed their functions
+as in a normal subject. He could, therefore, cause this or that muscle
+to contract alone, and could excite, for example, the action of the
+great zygomatic, giving to the face the expression of laughter,
+without the subject having any idea of what his physiognomy reflected;
+his face, by the action of the electricity, was laughing, while his
+thoughts might be indifferent or fixed on sad recollections; on the
+other hand, for example, by the contraction of the superciliary muscle,
+his countenance might express the most acute pain, while his thoughts
+might be quite indifferent or borne away by gay and pleasant ideas. In
+a word, Duchenne was able to realise, under the most precise conditions
+of experiment, an exact study of the uses of the muscles of expression.
+
+The work in which Duchenne has given the result of his labours is
+remarkable particularly for the magnificent atlas of photographs that
+accompany it, and which have been obtained by the above process. From
+these photographs have been reproduced as exactly as possible the
+several figures that accompany the descriptions which follow (Figs.
+95, 97, 99, 101, page 316 and following). We cannot enter here into
+a complete statement of the results obtained by Duchenne, but we
+will seek at least to show the serious and scientific value of these
+studies, and to inspire the student to refer to the original work.
+
+These studies have for the artist this important result--namely, to
+prove to him that frequently the contraction of a single muscle is
+sufficient to express an emotion, and that it is not necessary to
+change all the features in order to give to the face the stamp of pain,
+attention, menace, contempt, disgust, &c., each of these sentiments
+being expressed by a slight modification, either of the eye alone, or
+of the lip alone. Each expression has, so to speak, its own exact,
+precise, and separate mark, produced by a single local modification;
+but this local modification seems to be reflected throughout the
+physiognomy, and therefore, from unaided observation, artists had for
+a long time believed that, for example, attention and pain were shown
+by the combined action of a number of facial muscles. Now experiment
+proves that pain may be expressed solely by a muscle which raises and
+wrinkles the brows, and on a face (Fig. 99) where this muscle alone is
+contracted (_superciliary muscle_, page 320) the expression of pain is
+complete. We naturally believe that the mouth also takes part in it,
+but if we cover the upper part of the countenance, we perceive that the
+lower part of the face is in a state of complete repose.
+
+To bring to a close this history, which is not the least interesting
+part of the subject, we must say that the labours of Duchenne were not
+at first received with great favour in France. Physiologists as well
+as artists showed a certain distrust of a work which pretended to give
+precise rules and scientific laws to a subject about which it had been
+the custom to make fanciful and sentimental comparisons. Few persons
+understood the nature of the reason which forced Duchenne to choose as
+a subject for these experiments a poor man with a physiognomy almost
+imbecile in repose, and they did not consider that if this face was
+old, wrinkled, thin, and vulgar, there was the greater reason to be
+struck with the precision with which the electric excitation enabled
+the most opposite and characteristic expressions to be taken.
+
+As has been too often the fate of scientific discoveries, the work of
+Duchenne was neglected in France, and was not appreciated until it had
+been adopted by a foreign country. It was Darwin who made the results
+of the French physiologist the basis of his own interesting studies.
+
+It is not necessary to recall the extent and repute of the works of
+Darwin on _The Origin of Species_, on the _Evolution of Animals and
+Plants_, and on _The Descent of Man_. What this great naturalist has
+done for the general morphology of plants and animals he sought to
+do for the subject of physiognomy. Seeking in the logical chain of
+natural facts the cause of all biological phenomena, he endeavoured to
+discover by the attentive study of the movements of expression, and
+through their origin and development, a series of new arguments in
+favour of the theory of evolution. In a word, Darwin, by invoking the
+association of certain useful movements, and comparing the functions
+with the expressions with which they are associated, sought to explain
+why one muscle in particular rather than another is affected by the
+expression of this or that emotion. We cannot here enter further
+into the analysis of this philosophical work. It is sufficient to
+remark (having commended the perusal of it as most interesting to the
+artist[10]) that before we explain anything it is necessary that it
+should be firmly established. Therefore the explanation of the part
+that each muscle takes in the expression must be impossible until the
+fact of the action and the expression associated with the movement of
+the muscle has been scientifically demonstrated. The philosophical work
+of Darwin could not have been undertaken if it had not been preceded by
+the experimental work of Duchenne.
+
+Summarising Darwin’s argument, his thesis may be stated somewhat as
+follows: that every expression or bodily manifestation of emotion has
+a physical basis, and an origin in some _useful exercise_ of the
+particular muscles concerned; that such an action becomes habitual
+in the individual, and is transmitted from father to son, and from
+generation to generation; and that the actual physical cause is
+transferred to a mental condition, so that an action like knitting the
+brows--primitively for the purpose of actually clearer vision--becomes
+indicative of a mental state in which the emotion is expressed of a
+desire for a clearer mental vision, as when a man is engaged in any
+intellectual problem.
+
+Darwin further enunciated the important principle of _Antithesis_:
+which means the employment of exactly the opposite expression (it may
+be by the relaxation of muscles, or by the contraction of antagonistic
+muscles), to indicate an opposite or antagonistic attitude of mind.
+Thus joy is expressed by the contraction of a definite series of facial
+muscles; grief or dejection is expressed by the relaxation of these and
+the contraction of opposing muscles. The healthy, alert man holds his
+head erect; the depressed or miserable has a drooping gait.
+
+A third principle enunciated by Darwin as employed in producing the
+expression of emotion is _the direct action of the nervous system_, to
+a large extent independent of the will, and served mainly through the
+sympathetic nervous system, such as blushing, trembling, perspiration,
+&c.
+
+It is important, as Darwin points out, to bear in mind that emotion is
+expressed not only by facial expression, but by many other agencies as
+well; by the emission of sounds, by the voice in some cases, by the
+rattling of the tail quills in the case of the porcupine, &c.; by the
+inflation of the body, as in the hen who raises up all her feathers
+in maternal anger, or the dog whose hair stands on end; by gestures,
+rubbing, licking, caresses, kisses; or by the attitude and movements of
+the body, head, or limbs.
+
+In his book each emotion and its corresponding expression is carefully
+analysed, and the physical cause and the particular muscles engaged
+are pointed out. Thus Darwin says, “Weeping is the result of some such
+chain as follows: Children wanting food or suffering in any way, cry
+out loudly as a call to their parents for aid, like the young of most
+animals. Prolonged screaming leads to the gorging of the blood vessels
+of the eyes; and this causes first consciously and then habitually the
+contraction of the muscles round the eyes in order to protect them.”
+The mouth at the same time is opened widely to allow of a more vigorous
+scream. The overflow of tears is a consequence of the closure of the
+eyes.
+
+Again, in regard to the facial expression in laughter, Darwin suggests
+that as the primitive cause of laughter may have been a practical
+joke--or, as De Rochefoucauld put it, there is something pleasing in
+the misfortunes of one’s friends--the expression may be associated with
+the retraction of the angles of the mouth, and the exposure of the
+canine teeth, in preparation for self-defence if the victim of the joke
+should retaliate.
+
+The expression of disdain or disgust in the same way is associated with
+the contraction of muscles of the eye, nose, and mouth, primitively
+from purely physical causes, which have become connected with a mental
+attitude. The head is turned aside, and the eye is half closed to shut
+out an unpleasant sight; the nostril is raised at the sensation of a
+disagreeable smell, and the lips are curled in disgust at a nasty taste.
+
+There is not space in which to dwell further on these deeply
+interesting questions, for a study of which the reader is referred to
+Darwin’s masterly treatise on the subject.
+
+The figures which illustrate the work of Darwin are in a great measure
+only reproductions of the photographs published by Duchenne about ten
+years previously. However, as we have already mentioned, attention has
+been recalled in France to the works of Duchenne, a more favourable
+judgment has been passed, and justice has been rendered to him who
+had opened the way to the experimental study of physiognomy. In 1874
+the French began to devote, in the course of anatomy in the School of
+Fine Arts, several lectures to the account of what we must call the
+primer or grammar of the expression of physiognomy. Happy in seeing
+his works included in this classical course of instruction, Duchenne,
+whom death carried off a few years later, gave to the School of Fine
+Arts the complete series of large original photographs from which these
+publications are reduced, and this beautiful collection is to-day one
+of the most valuable in the French museum of anatomy (Muséum Hugnier).
+
+Although this account may appear long, it is nevertheless very
+incomplete, being given only with a particular object--that of
+comparing the works of Duchenne with those preceding him. Those of
+Duchenne will be made the basis of the studies which follow. We will
+finish by noting, as interesting and instructive, the works that treat
+in a more general manner of expression and physiognomy, such as those
+of Lemoine, Gratiolet, and Piderit.[11]
+
+
+
+
+                             CHAPTER XXVI.
+
+                         MUSCLES OF THE FACE.
+
+   Muscles of the upper part of the face: _Occipito-frontalis_
+   (attention); _orbicularis palpebrarum_ of the eyelids, superior
+   _orbital_ portion (reflection); _pyramidalis nasi_ (menace);
+   _superciliary_ (_corrugator supercilii_) (pain).--Muscles of
+   the middle region of the face: _Great zygomatic_ (laughter);
+   _lesser zygomatic_ and _levator labii superioris_ (tenderness,
+   sorrow); _levator labii superioris alæque nasi_ (weeping
+   bitterly), _compressor naris_ (lewdness).--Muscles of the
+   lower region of the face: _Orbicularis oris_; _buccinator_;
+   _depressor anguli oris_ (contempt); _depressor labii inferioris_
+   (disgust); _platysma_ muscle of the neck.--Classification into
+   muscles completely expressive and expressive by complement.--Of
+   associations possible and impossible with regard to mechanism
+   and with regard to the nature of the emotions.--Conclusion.
+
+
+The muscles of the face, which are attached to the skin, move and
+alter the shape of its folds and apertures. These different cutaneous
+parts are very complex, but at the same time known to persons who are
+the greatest strangers to anatomy. For them even it is unnecessary to
+describe here the eyebrows, the eyelids, the palpebral fissure, the ala
+or wing of the nose, and the lips. We will only point out, with regard
+to these parts, the significance of their various anatomical names, the
+employment of which will be useful in abridging the descriptions that
+follow.
+
+On the _eyebrow_ we distinguish a broad internal part (towards the
+median axis of the face) called the _head_ of the eyebrow, and an
+external part called the _tail_ of the eyebrow, which becomes thinner
+as it is removed from the middle line.
+
+On each palpebral fissure, at its inner end, is a small perforated
+papilla--the _lachrymal papilla_--the perforation in which is named
+the _punctum lachrymale_, carrying the tears from the surface of the
+eye into the nose by special ducts. Each of the two extremities of
+the palpebral fissure bears the name of the _canthus_, or _angle_. We
+distinguish, therefore, on the eyelids an _external canthus_ or _angle_
+characterised by its pointed form, and an _internal_ characterised by
+its rounded form, bounding a small oval space called the _lachrymal
+lake_, at the bottom of which a rose-coloured fleshy tubercle projects
+(the _caruncula lachrymalis_). External to this is a pale fold, the
+_plica semilunaris_, a rudiment of the third eyelid (found in birds).
+We also give the name of _commissure_ (or angle) to each extremity of
+the buccal aperture (_commissure of the lips_). The groove extending
+from the septum of the nose to the centre of the upper lip is known as
+the _philtrum_.
+
+Lastly, we must note a fold which normally exists in a more or less
+marked degree in every subject, and the changes of which take a great
+part in the expression produced by the various muscles of the cheeks.
+This is the _naso-labial fold_, so named because, arising from the
+region bounded by the cheek and the side of the nose, it is directed
+obliquely downwards and outwards, passes at a short distance from the
+posterior border of the wing of the nose, and terminates near the
+commissure of the lips. In the subject who served for the experiments
+of Duchenne (Fig. 99, page 320) this fold was strongly marked, as it
+generally is in all old people.
+
+The human head and face, the features, and the muscles which underlie
+the skin have, it is supposed, undergone progressive and retrogressive
+changes in the process of evolution. The cranium has expanded with the
+evolution of the brain, while the face has become smaller and feebler,
+and the teeth have shown distinct signs of degeneration and diminution,
+both in size and number.
+
+Of the soft parts of the face, the apertures of the eyes and mouth
+have increased in mobility and functional power and refinement of
+expression; while the nasal apertures and the ears illustrate a
+retrogression in evolution. The interior of the nasal cavity as well as
+the nostrils presents a simpler or more degenerate type in man than in
+the lower animals, in whom the sense of smell is so much more highly
+developed. The external ear is a good example of a _rudimentary organ_.
+Its parts have a definite form, and each wrinkle or corrugation has
+a separate name (see Fig. 93). It is composed of a mass of _elastic_
+cartilage (except in the tip or lobule) which penetrates into the
+passage of the ear in a tubular form. This cartilaginous _pinna_ is
+the shrivelled-up remains of the mobile funnel-shaped ear of the
+lower animals; and the _tip_ of the ear is represented by an angular
+projection (Darwin’s tubercle) placed on the edge of the rim of the ear
+(_helix_).
+
+The lobule is soft, and consists of a mass of fat enclosed in the skin.
+It is usually free from the neck, but in some cases (as, for example,
+in the right ear of the poet Byron) the lobule is attached to the skin
+of the neck, and is not in full relief. The muscles of the nose and
+ear are also degenerate, and the movements of the nostrils and of the
+ears are only rudimentary.
+
+In the same way the arrangement of the muscles underlying the skin of
+the neck and head presents examples of advance or retrogression when
+compared with the similar muscles of lower animals.
+
+  [Illustration: FIG. 93.
+
+   THE EXTERNAL EAR.--H. helix;--F.H. fossa of the helix;--A.H.
+   anti-helix;--F.A.H. fossa of the anti-helix; C. concha;--T.
+   tragus;--A.T. anti-tragus;--L. lobule;--D. Darwin’s tubercle.]
+
+In hairy animals the body is covered all over by a thin layer of muscle
+which underlies the skin, and is called the _panniculus carnosus_.
+
+In man the body has become almost denuded of hair, except on the head
+and face, and at the same time his capacity of facial expression is
+vastly greater than in one of the lower animals.
+
+The effect of these changes is seen in the condition of the panniculus
+carnosus. It has degenerated over the hairless trunk, and only remains
+normally as the _platysma myoides_ of the neck. But, on the other hand,
+the parts of the panniculus carnosus which have swept over the face
+and have surrounded the apertures of the eye and mouth in particular,
+have become differentiated into the complicated series of muscles of
+expression, rudimentary and feeble on the scalp and in relation to the
+pinna and the nasal opening, but highly organised in relation to the
+apertures of the eye and mouth.
+
+It is for the most part these highly differentiated muscles which have
+to be dealt with in this chapter in connection with the expression of
+the emotions.
+
+The muscles of expression (Fig. 94) are arranged in three series:
+one around the eyes and eyebrows, occupying the upper region of the
+face; the second about the nose; and the third around the aperture
+of the mouth, occupying the middle and especially the lower region
+of the face. The first series includes the _occipito-frontalis_, the
+_corrugator supercilii_, and the _orbicularis palpebrarum_; the second
+includes the _pyramidalis nasi_, _compressor naris_, and _dilator alæ
+nasi_; the third set is most numerous, comprising the _levator labii
+superioris alæque nasi_, _levator labii superioris_, _zygomaticus
+major_ and _minor_, the _levator anguli oris_, the _orbicularis oris_
+(to which we may add the _buccinator_), the _risorius_, _depressor
+anguli oris_, and _depressor labii inferioris_. Finally, in the neck
+and extending up to the lower jaw is the _platysma myoides_, which
+takes a considerable part in certain powerful expressions of the face.
+
+  [Illustration: FIG. 94.
+
+  (_From Cunningham’s “Text Book of Anatomy.”_)
+
+   THE MUSCLES OF THE FACE.--1, frontalis;--2, attrahens
+   aurem;--3, epicranial aponeurosis;--4, attolleus aurem;--5,
+   occipitalis;--6, retrahens aurem;--7, trapezius;--8,
+   parotid gland;--9, sterno-cleido-mastoid;--10, orbicularis
+   palpebrarum;--11, pyramidalis nasi;--12, compressor naris;--13,
+   levator labii supertoris alæque nasi;--14, levator labii
+   superioris;--15, levator anguli oris;--16, depressor alæ
+   nasi;--17, zygomaticus major;--18, Stenson’s duct;--19,
+   orbicularis oris,--20, risorius;--21, buccinator;--22,
+   depressor anguli oris;--23, depressor labii inferioris;--24,
+   masseter;--25, platysma myoides.]
+
+In the study of these muscles we will enter but little into anatomical
+details, but will content ourselves with pointing out the situation
+of the muscle, its fixed attachments to the bones of the face, its
+direction, and, lastly, the point on the skin where it takes its
+insertion. On the other hand, we must carefully inquire into its
+mechanism and the manner in which its contraction produces alterations
+in the skin of the face, and the nature and direction of the folds
+which it marks thereon. We must ask ourselves what expression results
+by the occurrence of these alterations in the face. And, lastly, we
+will endeavour to give a diagram of this expression after the mode of
+representation employed by Humbert de Superville (page 298).
+
+  [Illustration: FIG. 95.
+
+  CONTRACTION OF THE FRONTAL MUSCLES
+
+  (expressions of _attention_ and _astonishment_).]
+
+
+    A.--MUSCLES OF THE UPPER PART OF THE FACE (FOREHEAD, EYEBROWS,
+                      EYELIDS, AND ROOT OF NOSE.)
+
+1st. _Occipito-frontalis muscle_ (muscle of _attention_).--This
+muscle (1, Fig. 88, page 285) (Fig. 94) consists of an anterior and
+a posterior belly, connected by an intermediate membranous tendon
+covering the scalp. Its anterior belly extends as a fleshy sheet,
+quadrilateral in form, over each lateral half of the forehead. The
+muscles of each side are continuous with one another across the middle
+line. The anterior muscular portion is the _frontalis_. Its lower
+border is attached to the skin of the eyebrow, and blends with the
+orbicularis palpebrarum. From this origin its fibres ascend vertically
+and parallel to each other towards the region of the roots of the hair,
+and become continuous, at this level, with the membranous expansion of
+the _epicranial aponeurosis_. This aponeurosis, which covers the vault
+of the skull and is adherent to the skin of the scalp, is prolonged
+backwards to the occipital region, where it terminates in a bilateral
+fleshy layer, the _occipitalis_ muscle, attached to the superior curved
+line of the occipital bone.
+
+  [Illustration: FIG. 96.
+
+  Diagram of the _frontal muscles_ (_attention_).]
+
+In order to understand the mechanism of the occipito-frontalis muscle
+it is necessary to consider it as taking its fixed origin at the
+posterior part of the skull, through the medium of the epicranial
+aponeurosis and the occipitalis portion of the muscle; its insertion is
+its attachment to the deep surface of the skin of the eyebrow and the
+orbicularis palpebrarum. It has no bony attachment in the region of the
+forehead. The frontalis, therefore, in contracting, draws the skin of
+the eyebrow and the upper eyelid from below upwards, and consequently
+raises the eyebrow, and causes transverse folds to appear in the skin
+of the forehead.
+
+In examining (Fig. 95) a face in which this muscle is contracted we
+perceive that it expresses _attention_; if the contraction of the
+muscle is very great this expression of attention changes to that of
+_astonishment_. In entering into the detail of the changes that the
+face then presents we see that the eyebrow is raised and its superior
+convexity is very marked, that the eye is widely opened, clear, and
+brilliant, and that the forehead is furrowed on each lateral half by
+curved folds concentric with the curve of the eyebrows, continued more
+or less from one side to the other, and describing curves in the middle
+line with the concavity upwards. In a child or young woman, in whom
+the skin is supple and elastic, it does not give rise to the formation
+of folds, and the skin of the forehead remains quite smooth during
+the contraction of the frontal muscle, and then the elevation of the
+eyebrow, the exaggeration of its curve and the state of the eyes, open
+and bright, are sufficient to give the expression of attention.
+
+  [Illustration: FIG. 97.
+
+   THE UPPER PART OF THE ORBICULARIS PALPEBRARUM (_reflection_).]
+
+Figure 96 is the representation of _attention_, characterised here
+solely by the form of the eyebrows and the frontal folds.
+
+2nd. _The orbicularis palpebrarum_ (6, Fig. 88, and 10, Fig. 94).--The
+orbicular muscle of the eyes is a very extensive muscle which encircles
+the palpebral orifice. It is composed of numerous portions which
+can act more or less independently, and which have not all an equal
+importance in the expression of the face.
+
+_a._ One part of this orbicular muscle, called the _palpebral part_,
+is contained in the thickness of the eyelids, and produces by its
+contraction the closing of the eyes. If this contraction is moderate
+it produces only a certain drawing together of the eyelids and reduces
+the opening of the eyes to the form of a linear slit. This state of
+the palpebral opening does not constitute by itself an expression,
+properly speaking, but it may be complementary to various expressions;
+thus, associated with a slight contraction of the triangular muscle of
+the lips, which is the muscle of disgust and discontent (page 333), it
+gives to the countenance the expression of disdain and contempt.
+
+  [Illustration: FIG. 98.
+
+  Diagram representation of _reflection, meditation_.]
+
+_b._ A second part of the orbicular muscle is arranged in a circular
+manner on the outer side of the eyelids, and corresponds exactly to
+the contour of the orbital orifice of the skeleton (Fig. 58, page 174,
+and Fig. 88, page 285). This portion, which we may call the _orbital
+portion_, is divided into two parts: one, the _inferior fibres_, the
+contraction of which moves the lower eyelid slightly upwards and
+causes a furrow at its junction with the cheek, and without being
+expressive by itself, completes the expression of laughter by giving
+to it a character of frankness and truth; and the _superior fibres_,
+which merit more detailed study, for they produce by their action a
+characteristic expression of reflection, meditation, and contemplation.
+
+This _superior orbital_ portion of the muscle (muscle of _reflection_)
+is placed beneath the skin of the eyebrow, and its fibres, like it,
+describe an arc with the concavity downwards, of which the inner
+extremity is adherent to the internal border of the orbital opening.
+The mechanism, therefore, of this muscle is easily foreseen; for,
+like all curved muscles, more or less fixed at their extremities, it
+must in contraction straighten its curve. It accordingly acts in this
+way on the eyebrow, to the skin of which it is adherent, and effaces
+its curve, rendering it straight transversely; and it depresses,
+and consequently makes tense, the skin of the forehead, causing its
+wrinkles to disappear.
+
+  [Illustration: FIG. 99.
+
+  SUPERCILIARY MUSCLE (_sorrow_).]
+
+In examining a face in which this muscle is contracted we perceive
+that it expresses reflection. In Figure 97, owing to the excessive
+development of the eyebrow, which is greatly lowered, the hairs descend
+over the eyes, and the expression is rather that of painful reflection
+or of intense application of the mind pre-occupied with sadness; but
+we see in every case that this expression is obtained essentially by
+the lowering and straight direction of the eyebrow, which veils the
+eye and effaces all wrinkles on the forehead. This alteration in the
+features is precisely the reverse of that produced by the frontalis
+muscle, as is shown by the comparison of Figures 95 and 96, and in
+fact the two states of mind corresponding to the expression given by
+each of the muscles are precisely the reverse of each other. We cannot
+be at the same time attentive to an external object and meditating in
+reflection. Usually the succession of these states of mind and facial
+expression is as follows:--We are attentive to that on which we are
+looking, the eye open, brilliant, the eyebrow raised, and the forehead
+wrinkled (contraction of the frontal muscle); afterwards we reflect on
+what we have seen, and are, so to speak, abstracted from the external
+world--the eyebrow is lowered, the forehead smooth, and the eye veiled
+(by contraction of the superior fibres of the orbicularis palpebrarum),
+or the eyes may be closed (by contraction of the whole of the muscle).
+
+  [Illustration: FIG. 100.
+
+  Diagram representation of _sorrow_.]
+
+Figure 98 is the representation of _reflection_, characterised by
+the absence of the frontal folds, the depression of the eyebrows and
+the presence of two small vertical folds in the space between the
+eyebrows, to which the depression of the eyelid gives rise (Fig. 97).
+This representation of reflection (Fig. 98) does not acquire its full
+demonstrative significance until we compare it with that of attention
+(Fig. 96).
+
+3rd. _Pyramidalis nasi muscle_ (or _muscle of menace_).--This small
+muscle, situated in the space between the eyebrows on a level with
+the root of the nose (11, Fig. 94) (9, Fig. 88, page 285), is formed
+by short vertical fibres, which is attached by its lower end to a
+membranous expansion over the nasal bones (Fig. 58, page 174), and by
+its upper end to the deep surface of the skin of the space between the
+eyebrows.
+
+  [Illustration: FIG. 101.
+
+   GREAT ZYGOMATIC MUSCLE (expression of _gaiety_, of _laughter_).]
+
+The contraction of this muscle therefore produces the following
+result:--Taking its fixed insertion at the nasal bones, it draws
+downward the skin of the space between the eyebrows, forming short
+transverse folds, and depressing slightly the inner part of the eyebrow.
+
+In a face in which this muscle is contracted (see the atlas of
+Duchenne) the expression is that of harshness, menace, and aggression.
+Looking at the expression of countenance which Duchenne reproduced by
+this contraction, we can readily believe that if the subject had been
+represented in full, its attitude would have been one of menace; and
+the individual would be shaking his fist or brandishing a weapon.
+Moreover, anything which throws a shadow or a dark look between the
+eyebrows gives to the physiognomy a character of harshness, as when the
+contraction of the pyramidalis produces the transverse folds in this
+region. Therefore, in those persons in whom the eyebrows seem to meet,
+owing to an exaggerated development of hair in the space between, the
+physiognomy always presents at first sight the stamp of severity and
+harshness, which may not agree in the least with the true character of
+the subject. The expression of the pyramidalis is too delicate, and due
+to a change of the features too local and slight for us to express it
+by a drawing, as we have done in the case of the preceding muscles.
+
+4th. _Superciliary muscle_ (_corrugator supercilii_, or muscle of
+pain).--This short muscle is deeply hidden beneath the skin of the
+region of the head of the eyebrow. Its fixed attachment is to the
+frontal bone, above the superciliary arch; from this origin its fibres
+are directed outwards and slightly downwards to be inserted into the
+deep surface of the skin at the middle of the eyebrow.
+
+Its mechanism consists in drawing the eyebrow inwards and slightly
+upwards, and as it is attached to the middle of the eyebrow it draws
+it together at this point, namely, towards its inner part. The eyebrow
+is therefore, so to speak, abruptly hooked upwards and inwards, like
+a curtain that has been tucked up and attached to a fixed point. It
+therefore produces on the skin of the forehead folds concentric to
+this gathering together of the eyebrow and situated in the middle of
+the forehead, besides producing the vertical furrows, obvious in the
+figures, between the eyebrows.
+
+Figure 99 represents, after a photograph of Duchenne, the state of
+the physiognomy caused by the contraction of the superciliary muscle.
+This physiognomy has an expression characteristic of suffering, and
+any greater accentuation of the action of the muscle shows in a marked
+degree the expression of physical or mental agony.
+
+We see that the only parts changed in this expression (compare Fig.
+95, page 315) are the inner half of the eyebrow and the region between
+the eyebrows on the forehead; pain, therefore, is expressed by the
+raising of this part of the eyebrow and its gathering together abruptly
+in the middle of the forehead, and by the presence of the short folds
+immediately above this and the more extended folds occupying the middle
+region of the forehead.
+
+Figure 100 is a diagrammatic representation of pain, expressed only by
+changes in the neighbourhood of the inner part of the eyebrow (contrast
+with Fig. 102 following).
+
+
+             B.--MUSCLES OF THE MIDDLE REGION OF THE FACE.
+
+5th. The _great zygomatic muscle_ (_zygomaticus major_, muscle of
+_laughter_).--This muscle (17, Fig. 94, and 11, Fig. 88) has its fixed
+attachment on the cheek-bone; from this origin it is directed obliquely
+downwards and forwards, to be inserted into the deep surface of the
+skin near the angle of the mouth.
+
+6th. _Elevator of the angle of the month._--_The levator anguli
+oris_ is a muscle which largely aids the great zygomatic muscle in
+its action. It arises from the canine fossa of the upper jaw, and is
+directed downwards towards the angle of the mouth. It is inserted into
+the skin, and blends with the orbicularis oris (15, Fig. 94).
+
+  [Illustration: FIG. 102.
+
+  Diagram representation of _laughter_.]
+
+The mechanism of these muscles consists in drawing the angle of the
+mouth upwards and outwards, an action which results in some complex
+changes in the expression of the countenance. At first the orifice
+of the mouth is enlarged transversely, and its direction ceases to
+be straight, so that each lateral half is directed obliquely upwards
+and outwards. As the naso-labial line (Fig. 95) passes, at its lower
+end, near the commissure of the lips, this also is carried upwards,
+describing a slight curve concentric to the commissure of the lips,
+while the upper part of the line describes a curve with its convexity
+downwards. The skin of the cheek gathered up towards the cheek-bone
+becomes more prominent, and forms, below the outer angle of the eye,
+several radiating folds (commonly called crows’-feet), which throw a
+slight shadow beneath the external angle of the eye; this makes it
+appear as if the line of the eyelids is a little raised on the outer
+side (or oblique upwards).
+
+Figure 101, representing the contraction of the great zygomatic
+muscle, illustrates in a diagram the frank expression of gaiety and
+laughter, and we see that the alterations of expression take place
+only, as we have already said, in the line of the lips, the naso-labial
+line, and the external angle of the eyes.
+
+  [Illustration: FIG. 103.
+
+   Diagram representation of the _external common elevator_ (muscle
+   of _grief_).]
+
+Figure 102, giving the representation of laughter according to the
+preceding description of the great zygomatic muscle, is very similar
+to the corresponding figure of Humbert de Superville (Fig. 92, page
+299), only, in order to express the reality without having regard here
+to appearances, we have drawn the lines of the eyes horizontal; and,
+again, the naso-labial furrow has been represented with its form convex
+downwards and inwards for the upper two-thirds, and with the slight
+hook which its inferior extremity describes. This naso-labial furrow is
+of the utmost importance in the expressions produced by all the muscles
+belonging to the lips, as we shall see in the following description.
+
+7th. The _lesser zygomatic_ (_zygomaticus minor_) _and elevator of the
+upper lip_ (_levator labii superioris_, muscle of _grief_).--On the
+inner side of the great zygomatic muscle there exists frequently (10,
+Fig. 88, page 285), but not constantly, a small muscular fasciculus
+which arises from the anterior part of the cheek-bone and descends
+to be inserted into the thickness of the upper lip. This muscle,
+called the _lesser zygomatic_, does not take part in the expression
+of laughter; in fact, it changes the naso-labial furrow in the same
+manner as the following muscle (the external common elevator), and so
+expresses, as we shall see, emotion, sadness, and grief.
+
+8th. The _elevator_ of the upper lip (_levator labii superioris_)
+arises (14, Fig. 94, and 14, Fig. 88, page 285) from the inferior
+border of the bony margin of the orbit and descends to the upper lip.
+
+  [Illustration: FIG. 104.
+
+   Diagram representation of the _internal common elevator_
+   (muscle of _grief_ with tears).]
+
+Its contraction raises the upper lip itself, but not the labial
+commissure, so that each half of the line of the lips, raised within
+and remaining depressed at its outer extremity, becomes slightly
+oblique from above downwards and from within outwards (the reverse of
+the obliquity produced by the great zygomatic muscle); at the same time
+the centre of the naso-labial furrow is raised and the furrow becomes
+curved with its concavity downwards and inwards (the reverse of the
+curve produced by the great zygomatic).
+
+By means of these changes the countenance takes on the expression of
+discontent, emotion, and grief (see the atlas of Duchenne).
+
+We give here only one drawing (Fig. 103) in which are shown the two
+essential changes produced by this muscle (obliquity of the line of the
+lips and curve of the naso-labial furrow), which seems to us to show in
+a satisfactory manner the expression of grief in tears. We comprehend
+the value of this drawing better by comparing it with Figure 102.
+We see that the changes produced by the muscle of grief (lip and
+naso-labial furrow) are precisely the reverse of those produced by
+the muscle of laughter (_zygomaticus major_), just as the two
+corresponding emotions are the reverse of each other. We remark also
+how slight is the distance which separates these two muscles, and how
+delicate are the shades of anatomical arrangement which separate them,
+so delicate that authors do not agree as to whether the muscle found
+between them, the lesser zygomatic muscle, when it exists, should be
+considered as associated with the great zygomatic or, as we think,
+with the common elevator of the nose and upper lip. Beyond doubt their
+anatomical relations should remind us, in the nature of the emotions
+and their expression, how small a distance there is between laughter
+and tears.
+
+9th. The elevator of the nose and upper lip (_levator labii superioris
+alæque nasi_, muscle of sobbing, of weeping bitterly).--This muscle
+(13, Fig. 94, and 7, Fig. 88) arises above from the inner border of
+the orbit; it descends almost vertically to be inserted by some of its
+fibres into the wing of the nose, and by the majority into the upper
+lip, not far from its central portion.
+
+It therefore raises the middle part of the lip, the labial commissure
+remaining fixed, and gives accordingly to each half of the line of the
+lips a direction oblique downwards and outwards (like the preceding
+muscle, but in a more characteristic manner); at the same time it
+dilates the nostril by raising the wing of the nose; lastly, by the
+traction that it exercises vertically on the skin of the naso-labial
+furrow, it raises _en masse_ the inner and upper part of this
+furrow and renders it straight, causing it to form a species of groove
+wherein the tears flow when they pour abundantly from the inner angle
+of the eyelids. These changes (see the atlas of Duchenne) give to the
+countenance the expression of grief with abundant tears, or of weeping
+bitterly.
+
+The drawing of Figure 104 renders this expression to a certain degree,
+but it is difficult to realise it with the simple elements we use in
+these formulæ. We see that all the folds of the face converge towards
+the inner angle of the eye, or towards the point of attachment of this
+muscle.
+
+10th. _Transverse muscle of the nose_ (_compressor naris_, muscle
+of _lasciviousness_).--This muscle (12, Fig. 94, and 9, Fig. 88) is
+attached at its origin to the skin of the cheek on a level with the
+side of the nose, and is directed transversely forwards over the nose
+to join a thin aponeurosis which stretches over the bridge of the nose,
+and receives the insertions of these two muscles, and that of the
+pyramidalis nasi.
+
+This aponeurosis, which covers the bridge of the nose, forms a fixed
+point towards which these muscles draw the skin of the cheek and nose,
+so as to mark on the lateral surface of the nose a series of vertical
+folds (perpendicular to the direction of the muscle).
+
+Duchenne considered the change produced by these muscles to be
+characteristic of the expression of lasciviousness. Perhaps this muscle
+by itself is not sufficiently expressive, but when its contraction
+accompanies that of certain other muscles, we find very clearly in the
+physiognomy the element of lewdness pointed out by Duchenne. In his
+atlas this author gives the photograph of a countenance in which he
+had produced contraction of the frontalis, the great zygomatic, and
+the compressor naris; a countenance of which the expression may be
+directly interpreted as that of an old man in whom the _attention_
+(frontalis muscle) is _agreeably_ excited (great zygomatic) by
+a spectacle arousing _lewd_ ideas (compressor naris); the face
+produced by Duchenne would be, for example, a study in physiognomy for
+the head of the old man in the classic subject of Susanna in the bath.
+
+We have not attempted to represent by a drawing an unsatisfactory and
+perhaps doubtful idea of the expression of this muscle.
+
+
+              C.--MUSCLES OF THE LOWER PART OF THE FACE.
+
+11th. _Orbicularis muscle of the lips_ (_orbicularis oris_).--In the
+substance of the lips, as in the eyelids, a muscle is found, the fibres
+of which surround the orifice of the mouth--the orbicularis oris (19,
+Fig. 94, and 15, Fig. 88). This muscle principally possesses functions
+not primarily pertaining to expression, but to the various uses of
+the lips--prehension of food, mastication, speech, suction, etc.; the
+part it takes in physiognomy, although of importance, is secondary to
+these elemental functions. As in the orbicular muscle of the eyelids,
+we distinguish in it internal fibres corresponding to the free border
+of the lips and external fibres more peripherally placed. If the
+inner fibres only contract (internal orbicular) they close the mouth,
+and, diminishing the size of the orifice, cause the red surfaces of
+the lips to be brought closely together in their whole extent. If the
+outer fibres (external orbicular) contract only, they project the lips
+forwards and render their surfaces prominent and rounded, as in the
+expression of _pouting_ or in _kissing_.
+
+We need not dwell at length on the muscle which constitutes the fleshy
+layer of the cheeks and forms the lateral walls of the cavity of the
+mouth. This muscle, called the _buccinator_ (_buccinare_, to play the
+trumpet), is a thin sheet of muscle (21, Fig. 94) lining the hollow of
+the cheek in front of the line of the masseter. It is separated from
+that muscle posteriorly by a pad of fat (the remains of a suctorial
+pad), which in the infant is an important aid in suckling, and may
+be seen projecting into the side of the mouth. It takes a part in
+movements associated with the actions of the tongue and lips; it plays
+an important part in mastication by bringing beneath the crown of the
+teeth the food which passes outside the alveolar arches. It also aids
+in the articulation of sounds (speech) and in whistling and the playing
+of wind instruments (whence its name of _buccinator_), for it is the
+contraction of this muscle that expels from the mouth the air which
+inflates the cheeks. By its insertion into the angle of the mouth,
+where its fibres decussate with those of the orbicularis muscle, the
+buccinator is able to some extent to assist in the retraction of the
+mouth, as in grinning or snarling.
+
+12th. _The depressor of the angle of the mouth_ (_depressor anguli
+oris_, muscle of _contempt_).--This muscle belongs to the lower lip.
+It forms (22, Fig. 94, and 16, Fig. 88) a triangular layer, of which
+the base is attached to the lower jaw, external to the symphysis of the
+chin, and from this origin its fibres converge towards the angle of the
+mouth, where, by its apex, it is inserted into the deep surface of the
+skin.
+
+  [Illustration: FIG. 105.
+
+   TRIANGULAR MUSCLE OF THE LIPS (expression of _discontent_, of
+   _contempt_).]
+
+This muscle depresses the labial commissure, and therefore renders the
+line of the lips oblique in a direction downwards and outwards; again,
+it draws downwards the lower extremity of the naso-labial furrow so as
+to render this furrow almost straight, except at its lower end, which
+describes a slight curve embracing the labial commissure.
+
+The expression produced by a slight contraction of this muscle is
+that of _sadness_; marked contraction produces the expression of
+_contempt_. We have already seen (page 319) that a partial closing of
+the eyelids usually helps to complete the expression of contempt. Two
+other movements assist in this expression--a contraction of the common
+elevator of the nose and upper lip, raising the ala of the nose and
+curling the lip upwards; and a movement of the head to the opposite
+side. All these movements may have, as Darwin pointed out, a rational
+physical basis--the expression of the mouth implying a disagreeable
+taste, the uplifting of the nose an unpleasant smell, and the aversion
+of the head a disgusting sight.
+
+  [Illustration: FIG. 106.
+
+   Diagram representation of the expression of _discontent_, of
+   _contempt_.]
+
+Figure 105, copied from Duchenne, renders well, by the contraction
+only of the two triangular muscles of the lips, the expression of
+discontent and scorn. The depression of the angles of the mouth is
+characteristic, and the naso-labial furrow, very marked in the subject
+under experiment, is greatly changed in its direction and in the form
+of its inferior extremity, according to the mechanism that we have
+explained.
+
+Lastly, the drawing of Figure 106 gives, so to speak, a diagrammatic
+formula of contempt by means of the form of the inferior part of the
+naso-labial furrow, and the concentric folds which it produces below
+the angle of the mouth.
+
+13th. The _depressor of the lower lip_ (_quadratus menti: depressor
+labii inferioris_, muscle of _disgust_).--This muscle (23, Fig. 94, and
+17, Fig. 88), partly hidden by the depressor anguli oris, arises from
+the anterior part of the body of the lower jaw; from this origin the
+fibres ascend obliquely upwards and inwards to be inserted into the
+whole length of the lower lip.
+
+This muscle’s action is to depress the lower lip, turning it outwards
+more or less strongly, so as to produce the grimace characteristic of
+a person who, having introduced into the cavity of the mouth a morsel
+of food which he does not find to his taste, rejects it forcibly,
+forming a species of groove with the lower lip turned outwards; if the
+contraction is less energetic the physiognomy expresses disgust.
+
+We must refer to the atlas of Duchenne for the reproduction of this
+expression, always more or less rude, and have not attempted a drawing
+with a simple line as an indication of the labial fissure.
+
+14th. _Platysma muscle of the neck_ (_platysma myoides_).--In each
+lateral half of the anterior surface of the neck is a thin muscular
+sheet situated beneath the skin (25, Fig. 94, and 25, Fig. 74, page
+217). This platysma muscle is attached below to the upper part of the
+chest, from which origin its fibres are directed obliquely upwards and
+forwards towards the lower jaw, to be inserted into the edge of the
+jaw, and the skin of the chin, of the lower lip, and the commissure
+of the lips; the more superior fibres sweep forwards in a horizontal
+direction across the cheek towards the labial commissure, and
+constitute the _risorius muscle_ of Santorini (20, Fig. 94).
+
+The platysma, which is not of itself essentially a muscle of
+expression, adds its contraction to that of various muscles of the
+face, so as to give to the corresponding expression a character of
+terrible energy; the _risorius_ muscle does not therefore produce the
+expression of laughter (of gaiety), but only that of _grinning_, of
+forced laughter, threatening or sneering. The platysma in all these
+cases acts by depressing the lower jaw, slightly opening the mouth,
+and drawing the labial commissure downwards; it marks at the same time
+a series of transverse folds on the skin of the neck. These elements
+are capable of giving to the physiognomy a terrible character, which
+Leonardo da Vinci has well observed, in his chapter on the mode of
+representing a person in a state of violent anger, where he says, “it
+makes the sides of the mouth into a bow, the neck thick and swollen,
+and marked with wrinkles in front.”
+
+If the characteristic changes produced by the contraction of the
+platysma of the neck occur along with the contraction of the frontalis
+muscle, the countenance, as shown in Duchenne’s series of photographs,
+takes on an expression of attention and astonishment such as might be
+produced by a terrible spectacle. Associated with the contraction of
+the _superciliary_ muscle, the expression becomes that of acute pain,
+as, for example, in a wretch under torture, or a victim torn by a beast
+of prey. If the contraction of the _pyramidalis nasi_ is accompanied by
+that of the platysma we have the expression of a savage and barbarous
+threat.
+
+_General considerations._--_Associations and combinations._--From the
+enumeration we have made of the facial muscles from the forehead to
+the neck, we must perceive that among these muscles there are some
+which are by themselves completely expressive (_e.g._, the frontal,
+superciliary, and great zygomatic), and others which are expressive
+only in a complementary sense, or intended only to complete or change
+an expression produced by another muscle (such are the palpebral
+portion of the orbicularis of the eyelids, and the platysma of
+the neck), and lastly, others which are almost non-expressive, but
+yet associated with the true muscles of the expression (_e.g._
+the buccinator). But we have not space here to dwell on these
+classifications.
+
+A more important question is that of the association of the action of
+various muscles, and especially of the muscles which are completely
+expressive by themselves. The expression peculiar to each of these
+muscles is, so to speak, one of the syllables or words of the language
+of physiognomy, but, like every other language, physiognomy associates
+these syllables and words to arrive at its expressions. Now experience
+shows that usually the associations and combinations are composed of
+few elements. Usually two suffice; three muscles are sometimes in play
+simultaneously, hardly ever four.
+
+Again, if we endeavour to realise these combinations theoretically by
+supposing the contractions of two muscles associated at random, we
+soon perceive that among the combinations some are easy and ordinary,
+and this is on account of the nature of emotions which we suppose
+associated, and the mechanism of the corresponding muscles, while
+others are impossible for the same reason.
+
+The following is an example of easy combination related at the same
+time to the emotions and also to the muscular mechanism--viz., the
+combination of the contraction of the frontalis and of the great
+zygomatic muscles, as expressive of attention and laughter. On the one
+hand, attention (frontalis) might be excited by a spectacle which
+provokes laughter (zygomatic); on the other hand, the frontal muscle
+and the great zygomatic being situated the one in the forehead and
+the other in the cheek, acting, one on the eyebrow, the other on the
+lips, the mechanism of one is independent of that of the other; this,
+however, from an anatomical point of view, does not prevent the two
+contracting simultaneously, exactly as the biceps might contract in
+order to flex the forearm, at the same time that the common extensor of
+the fingers extends the digital phalanges.
+
+On the other hand, as impossible combinations discordant both to
+sentiment and muscular mechanism, we may, for example, consider the
+simultaneous contraction of the frontalis and the superior orbital
+portion of the orbicularis muscles of the eyelids. The first muscle
+expresses attention, the second reflection, or two opposite states of
+the mind, which cannot at the same time be open to external phenomena,
+and meditating on internal analyses. Again, the first muscle raises,
+the second depresses the eyebrow, which cannot be at the same time
+drawn in two opposite directions; just as, to take an example from the
+muscles of the limbs, the forearm cannot be at the same time flexed by
+the action of the biceps and extended by that of the triceps.
+
+By submitting them to the same analysis we see that nothing is easier
+or more concordant to their mechanism and to the emotions than the
+simultaneous contraction of the frontalis and the depressor anguli
+oris (attention and contempt), of the superciliary and the depressor
+labii inferioris (pain and disgust), the pyramidalis and the common
+elevator of the nose and upper lip (menace and sorrow), etc. On the
+contrary, for the same double series of reasons we find impossible and
+discordant associations, such as those of the great zygomatic and the
+depressor labii inferioris (gaiety and disgust), the pyramidalis and
+the superciliary (menace and pain), and of the common elevator of the
+nose and upper lip and the great zygomatic (sorrow and laughter).
+
+There are, however, combinations which at first sight appear discordant
+to the nature of the passions, but which are found, notwithstanding,
+not to have any obstacle to their realisation in the mechanism of the
+countenance. We take, for example, the superciliary and the great
+zygomatic: one expresses pain, the other laughter--two expressions of
+an opposite nature; however, as these muscles correspond, one belonging
+to the head of the eyebrow, the other to the labial commissure, they
+can act without one counteracting the other, and we may well understand
+their simultaneous contraction. Now on reflection we find that this
+association, anatomically possible, is often realised, notwithstanding
+the apparent incompatibility of the corresponding passions. In the
+midst of violent physical pain, which causes the involuntary and
+irresistible contraction of the superciliary, a serene and powerful
+will finds still the energy to smile. In order to find the realisation
+in a work of art it is sufficient to study the expression of the
+countenance of Seneca in the painting by Giordano. A similar example
+is offered by that of a young woman who has become a mother, and who,
+though still quivering with the pain of childbirth (_superciliary_
+muscle), is divided betwixt the physical pain and the mental joy of
+seeing the infant to whom she has given birth and at whom she smiles
+(_great zygomatic_ muscle).
+
+These latter examples show that the anatomical conditions take the lead
+up to a certain point of those conditions which result from the nature
+of the emotions, and that a combination of expressions is possible only
+when it can be realised by the action of the facial muscles.
+
+We will finish here these short studies of the anatomy of the face,
+happy if we have been successful in showing the artist that in the
+movements of the face there is neither fancy, caprice, nor inspiration,
+but that all is subject to exact and precise rules which are the
+orthography of the language of physiognomy, and that the possible
+combinations are both large and varied, so that the artist can preserve
+his liberty of action while conforming to these rules, as the poet
+observes those of grammar without being on that account embarrassed in
+the scope of his genius.
+
+
+
+
+                                 INDEX
+
+
+            A
+
+    Abdomen, Form of, 199
+
+    Abdomen, Muscles of, 198
+
+    Abduction and Adduction, 118, 121
+
+    Abductor Pollicis, 248
+
+    Acetabulum, 106
+
+    Achilles, Tendon of, 277
+
+    Acromio-clavicular Articulation, 57
+
+    Acromion Process, 57
+
+    Adductor Muscles of Hand, 248
+
+    Adductor Muscles of Thigh, 262
+
+    Agony, Expression of, 324
+
+    Alar Ligaments, 144
+
+    Alveoli, Dental, 178
+
+    Anatomical Neck of humerus, 60
+
+    Anatomical Snuff-box, 246
+
+    Anatomy, Definition and History of, 7
+
+    Anconeus Muscle, 240, 242
+
+    Anger, Expression of, 335
+
+    Angular Processes, 168
+
+    Ankle-joint, 148
+
+    Annular Ligament, Anterior of Wrist, 88
+
+    Anterior Triangle of Neck, 283
+
+    Antinöus, Measurement of, 187
+
+    Antithesis of Expression, 306
+
+    Apollo, Measurement of, 187
+
+    Arm, 67, 77
+
+    Arm, Muscles of, 224
+
+    Arm-pit, Hollow of, 215
+
+    Arthrology, 19
+
+    Articular Processes, 30
+
+    Association of Expressions, 336
+
+    Astragalo-calcaneo-scaphoid Joint, 157
+
+    Astragalo-scaphoid Articulation, 157
+
+    Astragalus Bone, 148, 152, 155
+
+    Athletes, Ancient, 11
+
+    Atlas, Vertebra, 32
+
+    Atmospheric Pressure, Influence of, 123
+
+    Attention, Expression of, 316
+
+    Auditory Canal, 169
+
+    Auditory Meatus, 169
+
+    Axilla, 215
+
+    Axis, Vertebra, 32
+
+
+            B
+
+    Back, Muscles of, 205
+
+    Bell, Sir Charles, 296
+
+    Bertini, Ligament of, 119
+
+    Biceps Brachialis, 224
+
+    Biceps Femoris, 266
+
+    Biceps Muscle, 222, 224
+
+    Bicipital Groove, 61, 67
+
+    Bicipital Tubercle, 78
+
+    Bigelow, Ligament of, 119
+
+    Blanc, Charles, 99
+
+    Bone, Structure of, 25
+
+    Brachial Index, 100
+
+    Brachialis Anticus Muscle, 228
+
+    Brachio-radialis Muscle, 238
+
+    Brachycephalic of Skull, 172
+
+    Breast, 196
+
+    Buccinator Muscle, 331
+
+    Buttock, 121
+
+
+            C
+
+    Calcaneum, 152
+
+    Camper on Facial Angle, 181, 296
+
+    Canalis Tarsi, 155
+
+    Canine Fossa, 176
+
+    Canine Teeth, 175
+
+    Canons, 99, 189
+
+    Capitellum, 68
+
+    Carpo-metacarpal Articulation, 92
+
+    Carpus, 87
+
+    Carpus, Muscles of, 239
+
+    Cartilages, 26
+
+    Caruncula Lachrymalis, 311
+
+    Caucasian Race, Facial Angle of, 184
+
+    Cephalic Index, 171
+
+    Cephalic Vein, 219
+
+    Cervical Vertebræ, 32
+
+    Cheek, Prominence of, 176
+
+    Chest, 41, 51
+
+    Chin, 177
+
+    Chondro-costal Articulation, 52
+
+    Chondro-sternal Articulation, 52
+
+    Clavicle, 55, 65
+
+    Coccyx, 104
+
+    Combination of Expressions, 336
+
+    Commissure of Eyelids, 319
+
+    Commissure of Lips, 311
+
+    Complexus Muscle, 211
+
+    Condyle of Jaw, 178
+
+    Condyles of Femur, 133
+
+    Condyles of Humerus, 69
+
+    Condyles, Occipital, 165
+
+    Conoid Ligament, 59
+
+    Contempt, Muscle of, 332
+
+    Coraco-brachialis Muscle, 215, 222, 227
+
+    Coracoid Process, 58
+
+    Coronal Suture, 167, 170
+
+    Coronoid Fossa, 69
+
+    Coronoid Process, 70, 178
+
+    Costal Cartilages, 51
+
+    Cotyloid Ligaments, 118
+
+    Coxo-femoral Articulation, 108
+
+    Cranium, 164
+
+    Cricoid Cartilage, 284
+
+    Crucial Ligaments, 136, 141
+
+    Crureus Muscle, 261
+
+    Cubitus, 69
+
+    Cuboid Bone, 152, 158
+
+    Cucullary Muscle, 208
+
+    Cuneiform Bones, 88, 152, 156, 157
+
+    Curves of Vertebral Column, 36
+
+
+             D
+
+    Darwin on Expression of Emotions, 304
+
+    Deltoid Impression, 68
+
+    Deltoid Muscle, 216
+
+    Diaphyses, 24
+
+    Digastric Muscle, 288, 289
+
+    Discontent, Expression of, 333
+
+    Discs, Intervertebral, 34
+
+    Discs, Vertebral, 28
+
+    Disgust, Expression of, 333
+
+    Dissections, 9, 12
+
+    Dog, Facial Angle of, 184
+
+    Dolichocephalic of Skull, 172
+
+    Dorsum Ilii, 106
+
+    Duchenne of Boulogne, 301, 308
+
+
+             E
+
+    Ear, 312
+
+    Egyptian Art, 2
+
+    Egyptian Canon, 99
+
+    Elbow, Articulation of, 71
+
+    Elbow, Hollow of, 234
+
+    Elevators of Lips, Muscles, 326
+
+    Ensiform Cartilage, 42
+
+    Epicranial Aponeurosis, 317
+
+    Epigastrium, 53
+
+    Epiphyses, 24
+
+    Erector Spinæ, 214
+
+    Expression, Antithesis of, 306
+
+    Expression, Muscles of, 294
+
+    Expressions, Combination of, 336
+
+    Extensor Brevis Digitorum, 279
+
+    Extensors of Fingers, Muscles, 239
+
+    Extensors of Toes, Muscles, 269
+
+    Eye, 312
+
+    Eye, Muscles of, 318
+
+    Eyebrow, 310
+
+    Eyelids, 319
+
+
+            F
+
+    Face, Muscles of, 291, 310
+
+    Face, Skeleton of, 173
+
+    Facial Angle, 181
+
+    Fascia Lata, 256
+
+    Female Figure, Formulæ of, 125
+
+    Femur, 116, 131
+
+    Femur, Neck of, 117
+
+    Fibula, 135, 147
+
+    Fingers, 93
+
+    Flexor Carpi Radialis, 235
+
+    Flexors of Fingers, Muscles, 237
+
+    Flexors of Toes, Muscles, 278
+
+    Foot, 151, 155, 160
+
+    Foot as a Canon, 185
+
+    Foot, Muscles of, 278
+
+    Foramen Magnum, 165
+
+    Forearm, 77
+
+    Forearm, Muscles of, 232, 244
+
+    Forehead, Muscles of, 316
+
+    Formulæ of Male and Female Figures, 125
+
+    Frederick of Germany, Edict of, 12
+
+    Frontal Bone, 166
+
+    Frontal Muscle, 316
+
+    Frontal Sinuses, 168
+
+
+             G
+
+    Galen, 9
+
+    Gastrocnemius Muscle, 273
+
+    Gemelli Muscles, 256
+
+    Gerdy on Canons, 185
+
+    Gladiator, Measurement of, 187
+
+    Glenoid Cavity, 59, 180
+
+    Gluteal Muscles, 252
+
+    Gracilis, 264
+
+    Grecian Art, 3
+
+    Grief, Muscle of, 326
+
+    Grinning, Expression of, 334
+
+    Groin, Fold of, 112
+
+    Groove, Bicipital, 61, 67
+
+    Gullet, 284
+
+    Gymnasium and Anatomy, 11
+
+
+            H
+
+    Hamstring Muscles, 265
+
+    Hand, 87
+
+    Hand, Muscles of, 232, 247
+
+    Head as a Canon, 185
+
+    Head, Bones of, 164
+
+    Head, Movements of, 33
+
+    Head, Muscles of, 291
+
+    Hip-bones, 105
+
+    Hip-joint, 118
+
+    Hips, Measurements and Proportions of, 124
+
+    Humerus, 60, 67
+
+    Hypothenar Eminence, 248, 249
+
+
+            I
+
+    Iliac Fossa, 108
+
+    Ilio-costalis Muscle, 214
+
+    Ilio-femoral Articulation, 118
+
+    Ilio-femoral Ligament, 119
+
+    Ilio-lumbar Ligament, 111
+
+    Ilio-pectineal Line, 107
+
+    Ilio-tibial Band, 144, 257
+
+    Ilio-trochanteric Band, 121
+
+    Ilium, 105
+
+    Incisive Fossa, 176
+
+    Incisor Teeth, 179, 180
+
+    Index, Brachial, 100
+
+    Index, Cephalic, 171
+
+    Index Finger, 91, 246
+
+    Infra-hyoid Muscles, 285
+
+    Infra-orbital Foramen, 174
+
+    Infra-spinatus Muscle, 212, 219
+
+    Inter-carpal Joint, 89
+
+    Inter-condyloid Notch, 133
+
+    Interosseous Ligament, 156
+
+    Interosseous Membrane, 147
+
+    Interosseous Muscles, 250
+
+    Interosseous Space, 80, 147
+
+    Inter-phalangeal Articulation, 94
+
+    Ischium, 105
+
+
+            J
+
+    Jaw, Articulation of, the, 180
+
+    Jaw, Muscles of, 292
+
+
+            K
+
+    Kissing, Expression of, 331
+
+    Knee, Articulation of, 131
+
+    Knee, Form of, 144
+
+    Knee, Ligaments of, 139
+
+
+            L
+
+    Lachrymal Lake, 311
+
+    Lambdoid, Suture, 170
+
+    Laocoon, Measurement of, 187
+
+    Larynx, 284
+
+    Lasciviousness, Muscle of, 329
+
+    Latissimus Dorsi Muscle, 209
+
+    Laughter, Expression of, 326
+
+    Lavater on Physiognomy, 297
+
+    Le Brun on Studies of, Expression, 296
+
+    Leg, 135, 146
+
+    Leg, Muscles of, 268
+
+    Ligamenta Subflava, 35
+
+    Ligamentum Nuchæ, 36
+
+    Ligamentum Teres, 116, 122
+
+    Linea Alba, 198
+
+    Linea Aspera, 133
+
+    Linea Semilunaris, 199
+
+    Lineæ Transversæ, 203
+
+    Lips, 311
+
+    Lips, Muscles of, 326, 330
+
+    Longissimus Dorsi Muscle, 214
+
+    Lumbricales Muscles, 237, 250
+
+    Luzzi, Mondino di, 12
+
+
+            M
+
+    Malar Bone, 176
+
+    Male Figure, Formulæ of, 125
+
+    Malleoli, 149
+
+    Mandible, 177
+
+    Manubrium of Sternum, 45
+
+    Masseter Muscle, 292
+
+    Masticating Muscles, 291
+
+    Mastoid Process, 169
+
+    Maxillary Bone, Inferior, 177
+
+    Maxillary Bone, Superior, 176
+
+    Menace, Expression of, 322
+
+    Mental Foramen, 178
+
+    Mental Process, 177
+
+    Mesaticephalic of Skull, 172
+
+    Metacarpo-phalangeal Articulation, 93
+
+    Metacarpus, 90
+
+    Metatarsus, 159
+
+    Michael Angelo, 14
+
+    Middle Finger, 91
+
+    Middle Finger as a Canon, 185
+
+    Modern Art, 5
+
+    Molar Teeth, 179
+
+    Mongols, Facial Angle of, 184
+
+    Monkeys, Facial Angle of, 184
+
+    Mouth, 312
+
+    Mouth, Muscles of, 325
+
+    Muscles in General, 189
+
+    Muscles, Movement of, 189
+
+    Muscles, Nomenclature of, 191
+
+    Mylo-hyoid Muscle, 288, 290
+
+
+            N
+
+    Nasal Bones, 168
+
+    Nasal Eminences, 168
+
+    Nasal Fossa, 175
+
+    Naso-labial Fold, 311
+
+    Naso-lachrymal Groove, 174
+
+    Navicular Bone, 152, 156, 158
+
+    Neck, Movements of, 282
+
+    Neck, Muscles of, 281, 334
+
+    Neck, Region of, 208
+
+    Negro, Facial Angle of, 183, 184
+
+    Neural Arch, 29
+
+    Neural Canal, 29
+
+    Nipple of, Breast, 196
+
+    Nomenclature, 22
+
+    Nose, Muscles of, 328
+
+    Nostrils, 312
+
+
+            O
+
+    Oblique Muscles of the Abdomen, 198
+
+    Obturator Foramen, 106
+
+    Obturator Membrane, 111
+
+    Obturator Muscle, 256
+
+    Occipital Bone, 164
+
+    Occipital Condyles, 165
+
+    Occipital Muscle, 316
+
+    Odontoid Process, 32
+
+    Œsophagus, 284
+
+    Olecranon, 70
+
+    Olecranon Fossa, 69
+
+    Olecranon Process, 71
+
+    Omo-hyoid Muscle, 286
+
+    Opponens Muscles, 248
+
+    Opposition, Movements of, 92
+
+    Optic Foramen, 175
+
+    Orbicular Muscle of Eyelids, 318
+
+    Orbicular Muscle of Lips, 330
+
+    Orbicularis Palpebrarum, 318
+
+    Orbital Processes, 176
+
+    Orbits, 173
+
+    Os Calcis, 152
+
+    Os Magnum, 88
+
+    Ossa Innominata, 105
+
+    Osteology, 19
+
+
+            P
+
+    Pain, Expression of, 335
+
+    Palmar Fascia, 248
+
+    Palmaris Brevis, 249
+
+    Palmaris Longus, 235
+
+    Palpebral Muscle, 318
+
+    Panniculus Carnosus, 313
+
+    Parietal Bones, 166
+
+    Patella, 134
+
+    Patella, Ligament of, 142, 260
+
+    Patellar Surface, 133
+
+    Pectineus Muscle, 262
+
+    Pectoral Muscles, 193
+
+    Pelvis, 103
+
+    Pelvis, Muscles of, 252
+
+    Perineum, 112
+
+    Peroneal Muscles, 158, 160, 271
+
+    Petrous Portion, 168
+
+    Phalanges of Fingers, 93
+
+    Phalanges of Toes, 160
+
+    Pharynx, 284
+
+    Philtrum, 311
+
+    Physiology, 9
+
+    Pinna, 312
+
+    Pisiform Bone, 88
+
+    Plantar Ligaments, 156
+
+    Plantaris Muscle, 277
+
+    Platysma Muscles, 211
+
+    Platysma of Neck, 334
+
+    Plica Semilunaris, 311
+
+    Pomum Adami, 284
+
+    Popliteal Space, 142
+
+    Posterior Triangle, 210
+
+    Poupart’s Ligament, 111
+
+    Pouting, Expression of, 331
+
+    Processes of Vertebræ, 30
+
+    Pronation, 82
+
+    Pronator Quadratus, 237
+
+    Pronator Radii Teres, Impression for, 78
+
+    Pronator Teres, 233
+
+    Proportion of Arm, 97
+
+    Proportion of Clavicle, 46
+
+    Proportion of Foot, 163
+
+    Proportion of Hips, 124
+
+    Proportion of Leg, 162
+
+    Proportion of Lower Limb, 161
+
+    Proportion of Pelvis, 114
+
+    Proportion of Sternum, 46
+
+    Proportion of Upper Limb, 96
+
+    Proportion of Vertebral Column, 38
+
+    Psoas Muscle, 263
+
+    Pterygoid Muscle, 292
+
+    Pubis, 105
+
+    Pyramidalis Abdominis Muscle, 204
+
+    Pyramidalis Muscle of Face, 322
+
+    Pyriformis Muscle, 256
+
+
+            Q
+
+    Quadratus Femoris, 256
+
+    Quadratus Menti, 333
+
+    Quadriceps Extensor Muscle, 259
+
+    Quadrumana, 148
+
+
+            R
+
+    Radial Head, 68
+
+    Radial Muscles, 239
+
+    Radio-carpal Articulation, 78
+
+    Radio-carpal Joint, 89
+
+    Radio-ulnar Articulation, 82
+
+    Radius, 70, 77
+
+    Ramus of Lower Jaw, 178
+
+    Rectus Abdominis, 202
+
+    Rectus Femoris, 259
+
+    Reflection, Expression of, 320
+
+    Renaissance Art, 4
+
+    Rhomboid Muscles, 212
+
+    Ribs, 46
+
+    Risorius Muscle of Santorini, 334
+
+    Roman Art, 4
+
+
+            S
+
+    Sacro-sciatic Ligaments, 105, 111
+
+    Sacrum, 103
+
+    Sadness, Expression of, 332
+
+    Sagittal Suture, 170
+
+    Salvage and Malgaigne’s Formula, 125
+
+    Sappey, Professor, on Canons, 188
+
+    Sartorius Muscle, 258
+
+    Scaphoid Bone, 88, 152, 156, 158
+
+    Scapula, 56
+
+    Scapulo-humeral Articulation, 60, 61
+
+    Scarpa’s Triangle, 263
+
+    Sciatic Notch, 109
+
+    Scorn, Expression of, 333
+
+    Semi-lunar Bone, 88
+
+    Semi-lunar Fascia, 225
+
+    Semi-lunar Ligaments, 137
+
+    Semi-membranosus Muscle, 267
+
+    Semi-tendinosus Muscle, 266
+
+    Serratus Magnus Muscle, 215, 220
+
+    Sexes, Formulæ of, 125
+
+    Shin Bone, 135
+
+    Shoulder, 55
+
+    Shoulder Blade, 56
+
+    Shoulder Joint, 61
+
+    Shoulder, Muscles of, 215
+
+    Sigmoid Cavities, 70
+
+    Sigmoid Notch, 178
+
+    Skeleton, Subdivisions of, 27
+
+    Skin, Muscles of, 292
+
+    Skull, 164
+
+    Sobbing, Muscle of, 328
+
+    Sole of Foot, 151, 160, 278
+
+    Soleus Muscle, 276
+
+    Sorrow, Expression of, 332
+
+    Sphenoid Bone, 170
+
+    Sphenoidal Fissure, 175
+
+    Spinal Crest, 37
+
+    Spinous Processes, 30
+
+    Spiral Groove, 68
+
+    Splenius Muscle, 211
+
+    Spring Ligament, 157
+
+    Sterno-cleido-mastoid Muscle, 281
+
+    Sterno-hyoid Muscle, 287
+
+    Sterno-thyroid Muscle, 287
+
+    Sternum, 41
+
+    Stomach, Pit of, 53
+
+    Stylo-hyoid Muscle, 287, 289
+
+    Styloid Process, 79, 136, 169
+
+    Subscapularis Muscle, 220
+
+    Sue on Physiognomy, 297
+
+    Superciliary Muscle, 323
+
+    Superville, Humbert de, 298
+
+    Supination, 80
+
+    Supinator Muscles, 238
+
+    Supinator Radii Brevis, 239
+
+    Supra-condyloid Ridge, 69
+
+    Supra-hyoid Muscles, 287
+
+    Supra-orbital Arches, 168
+
+    Supra-spinatus Muscle, 215, 219
+
+    Sustentaculum Tali, 155
+
+    Sutures of Skull, 170
+
+    Symphyses, Sacro-iliac, 110
+
+    Symphysis of Pubis, 110
+
+
+            T
+
+    Talus Bone, 152
+
+    Tarsus, 151, 155, 279
+
+    Teeth, 179
+
+    Temporal Bones, 168
+
+    Temporal Fossa, 170
+
+    Temporal Muscle, 293
+
+    Temporal Ridge, 166
+
+    Temporo-maxillary Articulation, 180
+
+    Tendo Achillis, 277
+
+    Tendons in General, 190
+
+    Tensor of Fascia Lata, 256
+
+    Teres Muscles, 212
+
+    Thenar Eminence, 248
+
+    Thigh, 116
+
+    Thigh, Muscles of, 256
+
+    Thorax, 41, 51
+
+    Threatening Expression, 335
+
+    Thyro-hyoid Muscle, 287
+
+    Thyroid Body, 285
+
+    Thyroid Cartilage, 284
+
+    Thyroid Foramen, 106
+
+    Thumb, 91
+
+    Tibia, 135, 146
+
+    Tibia, Tubercle of, 144
+
+    Tibialis Anticus, 268
+
+    Tibialis Posticus, 278
+
+    Tibio-astragaloid Articulation, 153
+
+    Tibio-fibular Articulation, 148
+
+    Titian and Andreas Vesalius, 14
+
+    Toes, 151
+
+    Toes, Muscles of, 269
+
+    Tongue, 284
+
+    Trachea, 284
+
+    Transversalis Muscles, 202
+
+    Trapezium, 88
+
+    Trapezius Muscle, 205
+
+    Trapezoid Bone, 88
+
+    Trapezoid Ligament, 59
+
+    Triangular Fibro-cartilage of Wrist, 79
+
+    Triangular Ligament of Hip-Bone, 111
+
+    Triceps Muscle, 223, 229
+
+    Trochanters, 116, 129
+
+    Trochlea, 68, 71
+
+    Trunk, Muscles of, 192
+
+
+            U
+
+    Ulna, 69, 77
+
+    Unciform Bone, 88
+
+
+            V
+
+    Vasti Muscles, 260
+
+    Vertebra, 29
+
+    Vertebra Prominens, 33
+
+    Vertebral Column, 27
+
+    Vertebral Furrow, 37
+
+    Vesalius, Andreas, 14
+
+    Vinci, Leonardo da, 13, 295
+
+
+            W
+
+    Weeping, Muscle of, 328
+
+    Windpipe, 284
+
+    Wrist, 87
+
+    Wrist Joint, 89
+
+    Wrist, Muscles of, 239
+
+
+            X
+
+    Xiphoid Cartilage, 42
+
+
+            Y
+
+    =Y=-shaped Ligament of Bigelow, 119
+
+
+            Z
+
+    Zona Circularis, 119
+
+    Zygomatic Arch, 169, 176
+
+    Zygomatic Muscles, 324
+
+    Zygomatic Process, 169, 176
+
+
+  PRINTED BY CASSELL AND COMPANY, LIMITED, LA BELLE SAUVAGE, LONDON,
+                              E.C.4 15719
+
+
+FOOTNOTES:
+
+[1] P. N. Gerdy: “Anatomy of the Forms of the Human Body for Painting,
+Sculpture, and Surgery.” Paris, 1829.
+
+[2] It is not always thus abroad. Thus in Germany there is the work
+of E. Harless (“Lehrbuch der Plastischen Anatomie für Akademische
+Anstalten.” Stuttgart, 1876: 2nd edit.).
+
+[3] We must look for other reasons than ignorance or indifference to
+explain the fixed scapulæ in pre-Phidian sculpture, or the exaggerated
+forms given to the extensor brevis of the foot and other muscles. This
+qualification is necessary to this general statement.--ED.
+
+[4] See Ludwig Choulant. _Gesichte und Bibliographie des Anatomischen
+Abbildungen._ Leipzig: 1852. (A very curious work wherein is found
+much information respecting the connection of anatomy with the plastic
+arts.)
+
+[5] Seroux d’Agincourt. _History of Art by its Monuments._ Paris:
+1811. Vol. i., p. 177.
+
+[6] Pierre Camper. “Dissertations sur les différences rúlles que
+présentent les traits du visage chez les hommes de différents pays et
+de différent âges.” (Œuvres posthumes. Paris, 1786.)
+
+[7] See especially; _Conférences sur l’expression des differents
+charactères des passions_, Paris, 1667. (These essays have been
+reprinted in the edition of Lavater, by Moreau. Vol. ix., 1820.)
+
+[8] _The Anatomy and Physiology of Expression_ (3rd edition, 1884,
+published after the death of Sir Charles Bell, and containing his last
+corrections.)
+
+[9] The edition to consult is that issued in 1820, in ten volumes, by
+Moreau.
+
+[10] Charles Darwin. _The Expression of the Emotions in Man and in
+Animals._
+
+[11] Albert Lemoine: _De la Physionomie et de la Parole_. Paris,
+1865. Pierre Gratiolet: _De la Physionomie et des Mouvements
+d’Expression_. Paris, 1865. Piderit: _Wissenschaftliches System
+der Mimik und Physiognomik_. 1867.
+
+
+Transcriber’s Notes:
+
+1. Obvious printers’, punctuation and spelling errors have been
+corrected silently.
+
+2. Some hyphenated and non-hyphenated versions of the same words have
+been retained as in the original.
+
+3. Italics are shown as _xxx_.
+
+
+
+
+
+*** END OF THE PROJECT GUTENBERG EBOOK 77743 ***
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+      Duval’s Artistic Anatomy | Project Gutenberg
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+</head>
+<body>
+<div style='text-align:center'>*** START OF THE PROJECT GUTENBERG EBOOK 77743 ***</div>
+
+
+<h1>DUVAL’S ARTISTIC<br>
+ANATOMY.</h1>
+
+
+
+<p class="center">Completely Revised
+with additional Original Illustrations.</p>
+
+<p class="center">Edited and Amplified by<br>
+A. MELVILLE PATERSON, M.D.</p>
+
+<p class="center xs">LATE DERBY PROFESSOR OF ANATOMY IN THE UNIVERSITY OF LIVERPOOL</p>
+
+  <div class="figcenter">
+  <img
+    class="p4" 
+    src="images/i_003.jpg"
+    alt="">
+  </div>
+
+<p class="center p4">FUNK &amp; WAGNALLS COMPANY<br>
+New York and London</p>
+
+<div class="chapter">
+<p class="center xs p4">First published <i>September</i> 1884</p></div>
+
+<p class="center xs"><i>Reprinted</i> 1885, 1888, 1890, 1891, 1892, 1894, 1896, 1898, 1899, 1901, 1903, 1904</p>
+
+<p class="center xs">Revised and Enlarged Edition 1905. <i>Reprinted</i> 1907, 1911, 1914, 1916, 1919</p>
+
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_v">[v]</span></p>
+
+<h2 class="p2">PREFACE TO THE REVISED EDITION</h2>
+</div>
+
+
+<p>Few words of preface are needed here. The preface of the original
+edition still holds good, and sufficiently defines the aims and scope
+of the book. The first object aimed at is to facilitate the study of
+artistic anatomy by the demonstration of the meaning of the appearances
+presented by the various parts of the body. Incidentally it is hoped
+that through close study the powers of observation will be quickened.
+By a simple narration of the structure of the body and its mechanism,
+particularly in relation to surface forms, it is hoped that the student
+of art may correctly and intelligently appreciate the why and wherefore
+of the parts which he is called upon to paint or model.</p>
+
+<p>One would reiterate and emphasise the necessity of two additional
+aids to this end. In his studies the student should have and use the
+opportunity of seeing and handling the separate bones and also an
+articulated skeleton; and where possible, he should have access to a
+fully equipped anatomical museum. He should further take advantage
+of all means of studying on the living model—on himself, on other<span class="pagenum" id="Page_vi">[vi]</span>
+models—and in casts, the movements, attitudes, and gestures of the
+body, and the resulting surface forms. By these two studies it becomes
+possible to correlate properly the superficial appearances with the
+deeper structures, such as bones, joints, and muscles, which are mainly
+responsible for the characteristic features presented in the living
+state.</p>
+
+<p>I have to express my indebtedness to my friend Dr. Thurstan Holland
+for the radiograph (Fig. <a href="#i_080">25</a>, p. 80) specially prepared by him for this
+work; and to the publisher of Cunningham’s Text Book of Anatomy for
+permission to use the figure (p. 315) of the muscles of expression.</p>
+
+<p class="r2">A. M. P.</p>
+
+<p><i>Liverpool</i>, <i>July, 1905.</i></p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_vii">[vii]</span></p>
+
+<h2 class="p2">AUTHOR’S PREFACE</h2>
+</div>
+
+
+<p>This little work is an epitome of a course of lectures which for about
+ten years I had the honour of delivering at the École des Beaux-Arts.
+If during that time I have arrived at a right understanding of the
+teachings of anatomy, I owe it to the great interest taken in the
+subject by my listeners of all ages; and my first duty is to thank
+them for their free interchange of ideas with me, thus enabling me
+to understand their requirements and the mode of satisfying them.
+But if the mode of exposition I have adopted is to be rendered clear
+to a constantly renewed audience, I must, in publishing this work,
+first explain to the reader how the lectures are to be used, and the
+principles which guided me in their production.</p>
+
+<p>This summary of anatomy is intended for those artists who, having
+commenced their special studies, have drawn the human form either from
+the antique or from the living model—who, in a word, have already what
+may be termed a general idea of forms, attitudes, and movements. It
+is intended to furnish them with a scientific notion of those forms,<span class="pagenum" id="Page_viii">[viii]</span>
+attitudes, and movements. Thus it is far less a description of the
+forms of a particular region than the anatomical explanation of those
+forms, and of their modifications in a state of repose or movement,
+that we have in view. That is why, instead of proceeding from the
+surface to the deeper organs and to the skeleton, we take the latter as
+the starting-point of our studies. In this way alone can we determine
+the laws which govern the movements of the adjacent segments of the
+limbs upon each other, and the movements of the limbs with regard to
+the trunk, as also the reciprocal action of these segments towards each
+other and in relation to the whole body.</p>
+
+<p>When to these fundamental notions is added a knowledge of the muscular
+masses which move these bones, the artist will at once be enabled to
+analyse through the skin, as through a transparent veil, the action of
+the parts which produce the various forms with their infinite variety
+of character and movement.</p>
+
+<p>This method of teaching, which may be said to proceed by synthesis,
+differs from that followed by the generality of works on this
+subject—books which treat by analysis. We make special allusion to the
+treatise of Gerdy,<a id="FNanchor_1" href="#Footnote_1" class="fnanchor">[1]</a> which is about the most careful work on plastic
+anatomy yet published, but which<span class="pagenum" id="Page_ix">[ix]</span> errs in a somewhat too lengthy
+description of external form, whilst sufficient space is not devoted
+to explaining the anatomical reasons of those forms. On the other
+hand, the remaining anatomical works in the hands of the students in
+our art schools generally comprise a volume of text and an illustrated
+atlas.<a id="FNanchor_2" href="#Footnote_2" class="fnanchor">[2]</a> Under these conditions, may I be allowed to remark, somewhat
+severely, it may be, that our young artists study the atlas by copying
+and re-copying the plates, but do not read the text? Thus it will be
+understood why, in this work, a different method has been pursued;
+and the fact of the plates being intermixed with the text, and in
+such a way that they cannot well be understood without the aid of the
+accompanying pages, will in all probability result in the student
+thoroughly and carefully perusing the text.</p>
+
+<p>Passing on to the manner of using the present work, we must acknowledge
+that reading anatomical details is at first dry; it will always be
+so, unless proceeded with in a simple and systematic manner. In the
+oral courses, the lecturer, handling the objects, and aided by his
+improvised drawings on the blackboard, can make the most complex parts
+interesting; and by adroit repetitions and varied illustrations, fix
+the attention and render the subject<span class="pagenum" id="Page_x">[x]</span> comprehensible, whereas it is
+quite different in a written description. In this case it is the reader
+who must animate the text for himself by examining and manipulating the
+parts needful for the elucidation of the descriptions. For this purpose
+a skeleton and a good plaster cast will suffice. On the cast, with the
+aid of the plates which accompany the text, it will be easy to follow
+the course of the muscles; and in this way alone will the study of them
+become profitable, the student being enabled to examine the model on
+different sides. By handling the bones, by placing the articulating
+surfaces in contact, the dry descriptions of the mechanism of the
+joints will take a tangible form, and will henceforth remain impressed
+on the memory. For example, notwithstanding our diagrams of the
+movements of pronation and supination, it is only by handling the bones
+of the forearm that the student will be enabled to fully appreciate the
+marvellous mechanism by which the rotation of the radius round the ulna
+is effected, allowing the hand to present alternately its palmar and
+dorsal surface; and the same is the case in regard to the skeleton of
+the foot and head, and the movements of the lower jaw, &amp;c.</p>
+
+<p>The artist will find in this book some pages devoted to the <i>facial
+angle</i>, to the forms of the head, <i>brachycephalic</i> and
+<i>dolichocephalic</i> heads, and<span class="pagenum" id="Page_xi">[xi]</span> to some other questions of
+anthropology, and will doubtless thank us for having considered here
+ideas which are daily becoming familiar to the general public.</p>
+
+<p>Our only regret concerning these anthropological studies is that the
+limits of this volume did not permit us to go deeper into the teachings
+of the anthropological laboratory, the direction of which was confided
+to me after the loss of our illustrious master, Broca.</p>
+
+<p>I take this opportunity of expressing my gratitude to my excellent
+master, Professor Sappey, who allowed me to borrow from his
+magnificent treatise on anatomy the figures on osteology and myology
+which constitute the chief merit of this work; and to my friend and
+colleague, E. Cuyer, whose skilful pencil reproduced the figures from
+the photographic atlas of Duchenne, as well as the two illustrations of
+the Gladiator, and the sundry diagrammatic drawings which complete the
+theoretical explanations of the text.</p>
+
+<p class="r2">M. DUVAL.</p>
+
+
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<h2>CONTENTS</h2>
+</div>
+
+<table class="smaller" style="max-width: 50em">
+  <tr>
+    <th class="chap">CHAPTER</th>
+    <th></th>
+    <th class="pag">PAGE</th>
+  </tr>
+
+  <tr>
+   <td class="chn">I.</td>
+   <td class="cht smcap">Introduction to the Revised Edition</td>
+   <td class="pag"><a href="#Page_1">1</a></td>
+  </tr>
+
+  <tr>
+   <td class="chn">II.</td>
+   <td class="cht smcap">Introduction.—Plastic Anatomy: Its History,
+Importance, and Objects—Order of these Studies—Division of Subject</td>
+   <td class="pag"><a href="#Page_7">7</a></td>
+  </tr>
+
+  <tr>
+    <th class="header" colspan="3"><img src="images/part1cont.jpg" alt=""
+style="height:1em;  padding:0 0em 0 0em;">—THE SKELETON, ARTICULATIONS,
+PROPORTIONS.
+</th>
+  </tr>
+
+  <tr>
+   <td class="chn">III.</td>
+   <td class="cht smcap">Osteology and Arthrology in General—Nomenclature—Vertebral
+Column</td>
+   <td class="pag"><a href="#Page_19">19</a></td>
+  </tr>
+
+  <tr>
+   <td class="chn">IV.</td>
+   <td class="cht smcap">Skeleton of the Trunk (Thorax)—Sternum—Ribs—Thorax as a Whole</td>
+   <td class="pag"><a href="#Page_41">41</a></td>
+  </tr>
+
+  <tr>
+   <td class="chn">V.</td>
+   <td class="cht smcap">Skeleton of Shoulder—Clavicle—Scapula—Head of Humerus—Shoulder Joint</td>
+   <td class="pag"><a href="#Page_55">55</a></td>
+  </tr>
+
+  <tr>
+   <td class="chn">VI.</td>
+   <td class="cht smcap">Humerus and Elbow Joint</td>
+   <td class="pag"><a href="#Page_67">67</a></td>
+  </tr>
+
+  <tr>
+   <td class="chn">VII.</td>
+   <td class="cht smcap">Skeleton of Fore-Arm—Radius and Ulna—Movements
+of Pronation and Supination</td>
+   <td class="pag"><a href="#Page_77">77</a></td>
+  </tr>
+
+  <tr>
+   <td class="chn">VIII.</td>
+   <td class="cht smcap">Skeleton of the Hand—Wrist (Carpus)—Hand
+and Fingers (Metacarpal Bones and Phalanges)—Proportions of the Upper Limb—Egyptian
+Canon—Brachial Index</td>
+   <td class="pag"><a href="#Page_87">87</a></td>
+  </tr>
+
+  <tr>
+   <td class="chn">IX.</td>
+   <td class="cht smcap">Skeleton of the Hips—Pelvis (Iliac Bones and
+Sacrum)—The Pelvis according to Sex</td>
+   <td class="pag"><a href="#Page_103">103</a></td>
+  </tr>
+
+  <tr>
+   <td class="chn">X.</td>
+   <td class="cht smcap">The Femur and the Articulations of the Hips—Proportions
+of the Hips and Shoulders</td>
+   <td class="pag"><a href="#Page_116">116</a></td>
+  </tr>
+
+  <tr>
+   <td class="chn">XI.</td>
+   <td class="cht smcap">The Femur and the Articulation of the Knee
+Joint; the Shape of the Region of the Knee</td>
+   <td class="pag"><a href="#Page_131">131</a></td>
+  </tr>
+
+  <tr>
+   <td class="chn">XII.</td>
+   <td class="cht smcap">Skeleton of the Leg: Tibia and Fibula, the
+Malleoli or Ankles—General View of the Skeleton of the Foot; Tibio-Tarsal Articulation</td>
+   <td class="pag"><a href="#Page_146">146</a></td>
+  </tr>
+
+  <tr>
+   <td class="chn">XIII.</td>
+   <td class="cht smcap">Skeleton of the Foot; Tarsus; Metatarsus; Toes and
+Fingers—Proportions of the Lower Limb—The Foot as a Common Measure</td>
+   <td class="pag"><a href="#Page_155">155</a></td>
+  </tr>
+
+  <tr>
+   <td class="chn">XIV.</td>
+   <td class="cht smcap">Skeleton of the Head: Skull (Occipital, Parietal,
+Frontal, Temporal Bones); Shapes of the Skull (Dolicocephalic and Brachycephalic
+Heads)</td>
+   <td class="pag"><a href="#Page_164">164</a></td>
+  </tr>
+
+  <tr>
+   <td class="chn">XV.</td>
+   <td class="cht smcap">Skeleton of the Face: The Orbital Cavities; Lower Jaw;
+Teeth; Facial Angle of Camper</td>
+   <td class="pag"><a href="#Page_173">173</a></td>
+  </tr>
+
+  <tr>
+    <th class="header" colspan="3"><img src="images/part2cont.jpg" alt=""
+style="height:1em;  padding:0 0em 0 0em;">—MYOLOGY.
+</th>
+  </tr>
+
+  <tr>
+   <td class="chn">XVI.</td>
+   <td class="cht smcap"> Of the Muscles in General—Muscles of the
+Trunk: Anterior Region (Pectoralis Major; the Oblique and Recti Muscles of the
+Abdomen)</td>
+   <td class="pag"><a href="#Page_189">189</a></td>
+  </tr>
+
+  <tr>
+   <td class="chn">XVII.</td>
+   <td class="cht smcap">Muscles of the Back: Trapezius, Latissimus Dorsi, and Teres Major Muscles</td>
+   <td class="pag"><a href="#Page_205">205</a></td>
+  </tr>
+
+  <tr>
+   <td class="chn">XVIII.</td>
+   <td class="cht smcap">Muscles of the Shoulder: Deltoid: Serratus
+Magnus; The Hollow and Shape of the Arm-pit</td>
+   <td class="pag"><a href="#Page_215">215</a></td>
+  </tr>
+
+  <tr>
+   <td class="chn">XIX.</td>
+   <td class="cht smcap">Muscles of the Arm: Biceps; Coraco-Brachialis:
+Brachialis Anticus; Triceps; Shape of the Arm</td>
+   <td class="pag"><a href="#Page_224">224</a></td>
+  </tr>
+
+  <tr>
+   <td class="chn">XX.</td>
+   <td class="cht smcap">Muscles of the Fore-Arm and Hand: The
+Anterior, External, and Posterior Superficial Muscles</td>
+   <td class="pag"><a href="#Page_232">232</a></td>
+  </tr>
+
+  <tr>
+   <td class="chn">XXI.</td>
+   <td class="cht"><span class="smcap">Muscles of the Fore-Arm and Hand</span> (<i>continued</i>):
+<span class="smcap">The Deep Posterior Muscles of the Fore-Arm
+(Anatomical Snuff-Box); Muscles of the Hand</span></td>
+   <td class="pag"><a href="#Page_244">244</a></td>
+  </tr>
+
+  <tr>
+   <td class="chn">XXII.</td>
+   <td class="cht smcap">Muscles of the Pelvis; the Gluteal Muscles;
+Fascia Lata; Muscles of the Thigh; Sartorius, Quadriceps, Adductors, &amp;c.</td>
+   <td class="pag"><a href="#Page_252">252</a></td>
+  </tr>
+
+  <tr>
+   <td class="chn">XXIII.</td>
+   <td class="cht smcap">Muscles of the Leg; Tendo Achillis; Muscles of the Foot</td>
+   <td class="pag"><a href="#Page_268">268</a></td>
+  </tr>
+
+  <tr>
+   <td class="chn">XXIV.</td>
+   <td class="cht smcap">Muscles of the Neck: Sterno-Cleido-Mastoid,
+Infra-Hyoid, and Supra-Hyoid Muscles</td>
+   <td class="pag"><a href="#Page_281">281</a></td>
+  </tr>
+
+  <tr>
+   <td class="chn">XXV.</td>
+   <td class="cht smcap"> Muscles of the Head; Muscles of Mastication;
+Muscles of Expression: History (Leonardo da Vinci; Humbert de Superville; Duchenne
+of Boulogne, and Darwin)</td>
+   <td class="pag"><a href="#Page_291">291</a></td>
+  </tr>
+
+  <tr>
+   <td class="chn">XXVI.</td>
+   <td class="cht smcap">Muscles of Expression; Possible and Impossible
+Combinations of Certain Contractions of the Muscles of the Face</td>
+   <td class="pag"><a href="#Page_310">310</a></td>
+  </tr>
+</table>
+
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p class="p4 center xl">DUVAL’S<br>
+ARTISTIC ANATOMY</p>
+</div>
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_1">[1]</span></p>
+
+<p class="p2 center xl smcap">Artistic Anatomy</p>
+</div>
+
+<h2>CHAPTER I.<br>
+<span class="subhed">INTRODUCTION TO THE REVISED EDITION.</span></h2>
+
+<p>In offering instruction in anatomy to artists, one feels compelled
+at the outset to attempt an answer to the question: Of what use is
+anatomy, scientifically considered, in the training of the artist?</p>
+
+<p>The artist requires to know his technique, just as an architect or an
+engineer needs to start with a knowledge of his materials.</p>
+
+<p>Looking backward, we see that science and art have ever progressed side
+by side. The history of Egypt, of Greece, of the Renaissance, shows
+glorious traditions of art, along with a full development of learning
+and philosophy. The advancement of science and of art has always
+occurred simultaneously, and there never has been a time when they have
+been divorced from one another.</p>
+
+<p>This is <i>par excellence</i> the age of technical education. There
+is no questioning the importance of science, or the aid the arts
+have received from it. We see it in architecture, in the influence
+of terra-cotta and steel frames; and in art, in the introduction of
+aniline colours.</p>
+
+<p>Painting and sculpture are the earliest of the arts, and have produced
+some of the most cherished<span class="pagenum" id="Page_2">[2]</span> monuments of history; and originally the
+chief object portrayed was the human form, in action or repose.</p>
+
+<p>Let us for a moment consider to what extent art has been indebted to
+anatomy in the production of the masterpieces of the past.</p>
+
+<p>1. <span class="smcap">Egypt.</span>—Egypt presents the first great School of Art, as of
+letters and philosophy, and from Egypt knowledge and culture flowed to
+Greece and Italy.</p>
+
+<p>The vestiges of Egyptian art extant to-day comprise for the most part
+statues—some of them portraits—coins, sculpture (in low relief),
+and flat, painted outlines. As a rule, the representations of the
+human form pretend to no exact representation of detail of form
+or expression, and for the most part are executed in a formal and
+stereotyped fashion.</p>
+
+<p>The amount of anatomical knowledge demanded by the art of Egypt could
+obviously be acquired by direct observation of the nude or semi-nude
+figures of the living. The history of Egypt, profoundly interesting
+from all points of view, is of special interest to the anatomist, and
+centres round the mode of treatment of the dead.</p>
+
+<p>Ascribed usually to a belief in the immortality of the soul, the
+ceremonial treatment of the body after death was elaborate, and
+essentially religious. The body was regarded as sacred, and the
+process of embalming was a religious rite, entrusted to a band of
+the priesthood—Charhebs or Paraschistes—and no greater detail of
+anatomical examination was permitted than was deemed necessary for
+the proper<span class="pagenum" id="Page_3">[3]</span> preservation of the body. This band of the priesthood was
+moreover shunned and outcast, and yet with all these disadvantages some
+knowledge of anatomical structure must have been obtained.</p>
+
+<p>It was only later, when Greek influence became felt, that a study
+of anatomy arose in the Medical School of Alexandria. Egypt was the
+nursing mother of medical teaching, and Alexandria was the first
+great medical school. Erasistratus (<span class="allsmcap">B.C.</span> 285) was the first
+great anatomist, and he utilised condemned criminals for dissection.
+Herophilus, a Jew, is said to have dissected 600 bodies.</p>
+
+<p>2. <span class="smcap">Greece and Rome.</span>—The historical importance of Egyptian art
+and the Alexandrine School of Anatomy lies in the influence which they
+exerted upon the culture of Greece and Italy.</p>
+
+<p>Science and art were introduced directly into Greece and Italy
+from Egypt. Anatomical knowledge in Greece begins with Hippocrates
+(<span class="allsmcap">B.C.</span> 400), who studied in Egypt under Democritus of Abdara.
+Galen, later (<span class="allsmcap">A.D.</span> 131), the great Roman physician, was a
+Greek by birth, and was taught his anatomy by Heraclianus at Alexandria.</p>
+
+<p>Art in those days had ideals. Its aims were the perpetuation of the
+godlike, the heroic, the representation of perfect beauty and manly
+strength. Every reproduction was required to be, if possible, more
+beautiful than the original—virtually, as Lessing says, a law against
+caricature. “By no people,” says Winckelmann, “was beauty so highly
+esteemed as by the Greeks.”</p>
+
+<p>Moreover, the Greek artist was surrounded by a crowd of witnesses,
+in the masterpieces of<span class="pagenum" id="Page_4">[4]</span> sculpture, and in the living active forms
+of perfect manhood and womanhood. In the games there were ample
+opportunities for the study of the nude; and every evanescent, subtle
+movement could be noticed of the lithe and supple frame of the athlete.</p>
+
+<p>Marked attention was given to physical culture; clothing was light,
+movements free, so that the environment was perfect for the purposes of
+the sculptor or figure-painter. Prizes were given for beauty, and the
+artists were the judges.</p>
+
+<p>The work of the artistic anatomist of those days was superficial in a
+double sense. Cremation was the usual mode of burial, the anatomist
+dissected apes, and beyond an occasional opportunity of handling human
+bones, little exact anatomical knowledge was available. But from the
+artist’s point of view all the anatomy they needed was before their
+eyes. The best models procurable were before them; and an art that in
+some respects is perfect owes nothing to the science of anatomy.</p>
+
+<p>3. <span class="smcap">The Art of the Renaissance.</span>—Egyptian art shows knowledge
+of form; Greco-Roman art, knowledge of form and proportion; the art of
+the Renaissance reaches a higher platform, in its portrayal of movement
+and the expression of emotion.</p>
+
+<p>Three factors combined to give the impetus to art at the time of the
+revival of learning. In 1315 Mondino di Luzzi made the first public
+demonstration of the anatomy of the human body. In 1400–1420 the
+process of wood-engraving, and subsequently the art of printing, were
+invented. Linked with these two facts, and with the general advance<span class="pagenum" id="Page_5">[5]</span>
+of learning, science, and art, was the great religious revival of
+that period. The religious sentiment gave the keynote to the artistic
+pre-eminence of the old masters. Their themes were great, and the
+result was a grandeur and a power that no merely decorative or
+realistic school can ever attain.</p>
+
+<p>In the 15th and 16th centuries, artists and anatomists are constantly
+found in association as fellow-workers and as personal friends. The
+great work of Andreas Vesalius on Anatomy was illustrated in an
+exact and artistic manner by Jan van Calcker, Titian’s favourite
+pupil. Leonardo da Vinci and Della Torre; Michael Angelo and Colombo;
+Benvenuto Cellini and Da Carpi; and other names might be cited to show
+the close relations of the artists and anatomists of those days.</p>
+
+<p>There is little doubt that the old masters seized every opportunity of
+becoming acquainted with anatomical structure. Vasari used to advise
+his pupils to study “the antique, the nude, and dissections from
+nature.” Michael Angelo was in the habit of first sketching his figures
+in the nude condition, and afterwards clothing them with the necessary
+drapery. Leonardo da Vinci has left few complete pictures; but there
+are numerous sketches in existence (notably at Milan) in which he has
+drawn with precision, dissections—<i>e.g.</i>, of the knee joint, with
+bones, ligaments, and muscles in proper position. Ruskin says of him:
+“We have in this great master a proof of the manner in which genius
+submits to labour in order to attain perfection.”</p>
+
+<p>4. <span class="smcap">Modern Art.</span>—For many reasons modern art is more dependent
+than ever upon anatomical<span class="pagenum" id="Page_6">[6]</span> knowledge. Not to dwell upon the ennobling
+power of religious feeling—notably absent from modern art—the artist
+of the present day suffers from the plutocratic conditions of modern
+life, the inartistic fashions of modern dress, and the difficulty of
+obtaining accurate and well-formed human models; and is compelled to
+depend more and more upon a scientific knowledge of anatomy.</p>
+
+<p>Among the old masters there is often an excessive exhibition of
+anatomical structure, and this is liable to occur even more in some of
+the work of modern artists. A little knowledge is a dangerous thing;
+and it is of supreme importance that the anatomical knowledge used
+by the painter or sculptor should be properly applied, so that form,
+proportion, contour, and expression may all have equal value.</p>
+
+<p>It is too common, unfortunately, for present-day models to be
+disproportionate in form and deficient in muscular development, and the
+mistakes of nature are too often reproduced, in the form of defects or
+exaggerations, in modern sculpture and pictures. The student should
+seize every opportunity of studying the well-developed living nude form
+in action in order to obtain an adequate idea of the pattern which he
+desires to copy.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_7">[7]</span></p>
+
+<h2>CHAPTER II.<br>
+<span class="subhed">INTRODUCTION.</span></h2></div>
+
+<div class="blockquot">
+
+<p class="hangingindent">Anatomy in general; the anatomy of the external forms of man;
+physiology of the same.—Origin of the knowledge of the Greek
+artists of the anatomy of external forms; the influence of
+gymnastics upon Greek art.—The Renaissance and anatomical
+study: Mondino di Luzzi (1316).—The anatomical studies of
+Leonardo da Vinci, Michael Angelo, and Raphael.—Titian
+and Andreas Vesalius.—The anatomical course of the School
+of Painting (1648).—What the artist requires in the study
+of anatomy: proportions, forms (or contours), attitudes,
+movements.—The order of these studies; divisions of the subject.</p>
+</div>
+
+
+<p>Anatomy, as the derivation of the word indicates (from <i>ἀνὰ</i>,
+across, and <i>τομὴ</i>, section), is the study of the parts composing
+the body—muscles, bones, tendons, ligaments, various viscera,
+&amp;c.—parts which we separate one from the other by dissection, in order
+to examine their shapes and their relations and connections.</p>
+
+<p>This study may be accomplished in various ways: (1) from a
+philosophical and comparative point of view, by seeking the analogies
+and differences that the organs present in animals of different
+species—which is called <i>Comparative Anatomy</i>; (2) from a
+practical point of view, by seeking out the arrangement of organs, the
+knowledge of which is indispensable to the physician and surgeon—this
+is called <i>Surgical</i> or <i>Topographical Anatomy</i>; (3) by
+examining the nature and arrangement of the organs which determine the
+external forms of the body—this is <i>Plastic Anatomy</i>, called also
+the<span class="pagenum" id="Page_8">[8]</span> <i>Anatomy of External Forms</i>, the <i>Anatomy of Artists</i>.
+It is the anatomy of external forms that we shall study here; but
+the artist ought to know not only the form of the body in repose, or
+in the dead subject, but also the principal changes of form in the
+body when in a state of activity, of movement, and of function, and
+should understand the causes which determine these changes. Plastic
+anatomy ought to be supplemented by a certain amount of knowledge of
+the functions of the organs, <i>e.g.</i>, muscles and articulations;
+so that under the title of anatomy of the external forms of man we
+shall study at the same time the anatomy and the physiology of the
+organs which determine these forms. We should be contending for what
+has been long since conceded, were we to endeavour to show to what an
+extent the studies of anatomy and physiology are indispensable to the
+artist, who seeks to represent the human form under many and various
+types of action. Nevertheless, it may be useful to explain how the
+<i>chefs-d’œuvre</i> of ancient art have been produced with admirable
+anatomical exactness by men who certainly had not gone through any
+anatomical studies, and to show what special conditions aided them to
+acquire, by constant practice, the knowledge that we are obliged to
+seek day by day in the study of anatomy.</p>
+
+<p>The Greek sculptors have reproduced the human form with marvellous
+anatomical exactness; in fact, the works of Phidias (the <i>Theseus</i>
+and the <i>Ilissus</i>), those of Myron (the <i>Discobolus</i>),
+those of Lysippus and of Praxiteles (the <i>Sleeping Fawn</i>), those
+of Agasias (the <i>Fighting Gladiator</i>), and other masterpieces<span class="pagenum" id="Page_9">[9]</span>
+given as models in all the schools of art, are such that it is
+impossible to find fault with them, or to discover in them the least
+inexactitude, either from an anatomical or a physiological point of
+view;<a id="FNanchor_3" href="#Footnote_3" class="fnanchor">[3]</a> in fact, not only are the muscles, for example, prominent
+exactly in their places, but, more than that, these prominences are
+differently accentuated in corresponding muscles on the different
+sides, according to the nature of the movement; one side will present
+the muscles swelled up in a state of contraction, or the muscles may
+be in repose—that is, relaxed and relatively flattened. At the time
+when these works of art were produced, the study of anatomy, or even
+the dissection of the human body, had not yet been attempted; the
+respect in which the dead body was held was such that the physicians
+themselves, who should have been able to justify their motives for this
+study, had never as yet dissected a human body. In order to supply this
+want of direct knowledge Hippocrates had dissected animals, and had
+arrived at certain conclusions by the analogy that exists between the
+organs of quadrupeds and those in man. Galen himself dissected monkeys
+only, seeking to confine his examination to animals whose anatomical
+construction might be considered as most closely resembling that of
+man. Galen never possessed a human skeleton, for in a passage in his
+anatomical works he states the pleasure that he<span class="pagenum" id="Page_10">[10]</span> found in studying
+at last some human bones that had been deposited in a marshy place
+by a river which had overflowed its banks. We seem, then, to have a
+singular contradiction between these two facts, as we know on the one
+hand that the Greek artists have shown in their works a most rigorous
+anatomical exactitude, whilst on the other hand neither they nor their
+contemporary physicians and surgeons had made a study of the anatomy of
+man by the practice of dissection.</p>
+
+<p>But this contradiction disappears altogether when we examine the
+conditions which permitted those artists to have constantly before
+their eyes the nude human body, living and in motion, and so set them
+to work to analyse the forms, and thus to acquire, by the observation
+of the mechanism of active muscular changes, a knowledge almost as
+precise as that which is now obtained by the accurate study of anatomy
+and physiology. It is sufficient, in fact, to recall to mind the
+extreme care the ancients gave to the development of strength, and of
+physical beauty, by gymnastic exercises. In Homer we see the heroes
+exercising themselves in racing, in quoit-throwing, and in wrestling;
+later we come to the exercise of the athletes who trained themselves to
+carry off the palm in the Olympic games; and it is evident, in spite
+of the ideas that we hold now respecting wrestlers and acrobats, that
+the profession of an athlete was considered a glorious one, as being
+one which not only produced a condition of physical beauty and high
+character, but constituted in itself a true nobility. Thus the life
+of the gymnast came to exercise a decisive influence<span class="pagenum" id="Page_11">[11]</span> on Greek art.
+The prize of the conqueror in the Olympic games was a palm, a crown
+of leaves, an artistic vase; but the chief glory of all was that the
+statue of the victor was sculptured by the most celebrated artist of
+the time. Thus Phidias produced the handsome form of Pantarces, and
+these athletic statues form almost the only archives of the Olympiads,
+upon which Emeric David was able to reconstruct his Greek Chronology.
+From these works, which became ideals of strength and beauty, the
+artist had long been able to study his model, which he saw naked
+every day, not only before his exercises, whilst rubbing himself over
+with oil, but during the race, or the leaping match, which showed the
+muscles of the inferior extremities, or during the throwing of the
+quoit, which made the contractions of the muscular masses of the arm
+and the shoulder prominent; and during the wrestling matches, which
+from the infinite varieties of effort, successively brought all the
+muscular powers into play. Was it then surprising that the images
+of the gods, destitute of movement and of life, which had so long
+satisfied the religious sentiment of the people, were succeeded by
+artistic representations of man in action in statues such as could
+embody the idea of strength and beauty, studies of the living statues
+of the gymnasium? Further, we shall see the decline of art proceed side
+by side with the abandonment of the exercises of the gymnasium. Much
+later, in the Middle Ages, art awoke and embodied ideas in figures
+without strength and life indeed, but which nevertheless express in a
+marvellous manner the mysterious aspirations of the<span class="pagenum" id="Page_12">[12]</span> period; but these
+have not anything in common with the realistic representation of the
+human form, well developed and active, as seen in Greek art. At the
+time of the Renaissance, artists not having any longer a living source
+of study in athletic sports, recognised the necessity of seeking for
+more precise knowledge in the <i>anatomical</i> study of the human
+body, in addition to the inspiration drawn from the study of the
+antique, and thus we see that the revival of the plastic arts occurred
+simultaneously with the introduction of the practice of dissection.
+This was not brought about without some difficulty.</p>
+
+  <div class="figcenter" id="i_013" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_013.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 1.</p>
+     <p class="p0 sm">Reproduction of a drawing of an anatomical study by Leonardo da
+Vinci. (Choulant’s work, page 8.) This design represents the
+minute dissection of the muscles of the lateral region of the
+neck and trunk.]</p>
+  </div>
+
+<p>In the year 1230, Frederic II., Emperor of Germany, and King of the Two
+Sicilies, passed a law prohibiting the practice of medicine without
+the practitioners having first studied the anatomy of the human body.
+In spite of two papal excommunications hurled against the author of
+this edict, dissections were henceforth regularly pursued in Italy;
+and one century later—in the year 1316—Mondino di Luzzi was able to
+write the first treatise on human anatomy, containing descriptions
+made from studies of the dead body. This treatise was printed in 1478.
+Artists rivalled physicians in the ardour with which they pursued
+their anatomical studies; and it may be said that all the painters
+and sculptors in the fifteenth century gave most careful attention to
+dissection, or at least studied demonstrations made upon the dead body,
+for all have left, amongst their drawings, studies that leave no doubt
+on this head. Among the great masters it may be noted that Leonardo
+da Vinci (14521519)<span class="pagenum" id="Page_13">[13]</span> left thirteen portfolios of various drawings and
+studies, among which are numerous anatomical studies of remarkable
+fidelity. The greater number of these were taken from Milan by the
+French in 1796, and afterwards they were in part restored to Italy;
+some of them, however, went to enrich the British Museum in London,
+and were published by<span class="pagenum" id="Page_14">[14]</span> Chamberlain.<a id="FNanchor_4" href="#Footnote_4" class="fnanchor">[4]</a> In Fig. <a href="#i_013">1</a> is reproduced one
+of these anatomical drawings. It shows with what care—perhaps with
+over-scrupulous care—the illustrious master endeavoured to separate
+by dissection the various fasciculi of pectoral muscle, deltoid, and
+sterno-cleido-mastoid. It may be noted also that in his <i>Treatise
+on Painting</i>, Leonardo da Vinci devotes numerous chapters to the
+description of the muscles of the body, the joints of the limbs and
+of the “cords and small tendons which meet together when the muscles
+contract to produce its action,” &amp;c.; and finally, in this same
+<i>Treatise on Painting</i>, he makes allusion at different times to
+a <i>Treatise on Anatomy</i>, which he intended to publish, and for
+which he had gathered together numerous notes. These are fortunately
+preserved in the Royal Library at Windsor.</p>
+
+<p>Michael Angelo also (1475–1564) made at Florence many laborious studies
+of dissection, and left among his drawings beautiful illustrations
+of anatomy, of which several have been published in Choulant’s work,
+and by Seroux d’Agincourt.<a id="FNanchor_5" href="#Footnote_5" class="fnanchor">[5]</a> Finally, we have numerous drawings by
+Raphael himself, as proof of his anatomical researches, among which we
+ought to mention, as particularly remarkable, a study of the skeleton
+intended to give him the exact indication of the direction of the limbs
+and the position of the joints for a figure of the swooning<span class="pagenum" id="Page_15">[15]</span> Virgin
+in his painting of the Entombment (Choulant, p. 15). We cannot end
+this short enumeration without quoting further the names of Titian
+and Andreas Vesalius, in order to show into what intimate relations
+artists and anatomists were brought by their common studies. Titian,
+in fact, is considered the real author of the admirable figures which
+illustrate the work—“De Humani Corporis Fabrica”—of the immortal
+anatomist, Andreas Vesalius, justly styled the restorer of anatomy. It
+is necessary, however, to add that though some of the drawings are by
+Titian, the greater number were executed by his pupil, Jan van Calcker,
+as is pointed out in the preface to the edition of the work published
+at Basle in 1543.</p>
+
+<p>The renaissance of the plastic arts and that of anatomy were therefore
+simultaneous, and closely bound up one with the other; ever since
+that time it has been generally recognised that it is necessary to
+get by anatomical study that knowledge of form which the Greeks
+found themselves able to embody in consequence of the opportunities
+they had of studying the human figure in the incessant exercises of
+the gymnasium. Again, in 1648, when Louis XIV. founded at Paris the
+<i>Académie de Peinture et de Sculpture</i>, which later on took
+the title of the <i>École des Beaux-Arts</i>, two sections of study
+were instituted side by side with the studios properly so called,
+for imparting to the pupils instruction considered as fundamental,
+and indispensable to the practice of art. These were the sections of
+perspective and anatomy.</p>
+
+<p>It is not our place to plead, otherwise than by<span class="pagenum" id="Page_16">[16]</span> the preceding
+historical considerations, the cause of anatomy in its relation to
+painting and sculpture; but we ought at least to examine what method
+is likely to prove the most useful for its study. If each anatomical
+detail does not correspond to an artistic need we are liable in
+following any treatise written with other than an artistic aim to be
+entangled in superfluous names and useless descriptions; while at the
+same time we might neglect details which are to the artist of great
+importance, although considered of secondary value by authors who have
+written especially for students in medicine.</p>
+
+<p>We ought, then, to ask ourselves, in the first place, what are the
+ideas that the artist should seek for in his study of anatomy? To this
+question all will reply that the ideas of proportion, of form, of
+attitudes and movements are those in which anatomy is relied upon to
+furnish precise rules; and as the expression of the emotions, either in
+painting or sculpture, cannot be reproduced except by various changes
+in the general attitude of the body, and in the special mechanism of
+the physiognomy moved by the muscles, we must conclude that our study
+should deal not only with proportions, form, attitudes and movements,
+but also with the expression of the emotions and passions. This, then,
+is the object to be attained. Suppose we try to accomplish it by
+examining in a first series of studies all that belongs to proportions;
+afterwards, in a second series, all that has relation to form; in a
+third, attitudes, &amp;c. Such an order of proceeding, logical though
+it be, will have the disadvantage<span class="pagenum" id="Page_17">[17]</span> of causing numerous repetitions,
+and the more serious inconvenience of artificially separating parts
+which in the structure of the body are intimately connected. Thus,
+form is determined sometimes by osseous prominences, sometimes by
+the soft parts, which may be muscular or tendinous. Attitudes are
+determined by the muscles; but these are subject to laws which result
+from the position and action of the joints; so with movements in the
+expression of which it is necessary to consider, at the same time, what
+the conformation of the osseous levers (the direction of the bones
+and their articulation) allows, as well as that which the muscles
+accomplish, also the direction of the muscles and the differences of
+shape produced by their swelling and tension in action, as well as
+when the antagonistic muscles are relaxed. Proportions themselves
+cannot be defined without an exact knowledge of the skeleton, for it
+is the bones alone which furnish us with the landmarks from which to
+take measurements. A knowledge of the bones and of their articular
+mechanism is indispensable to us, that we may guard ourselves against
+being deceived in certain apparent changes of length in the limbs when
+certain movements take place.</p>
+
+<p>We see, then, that all the ideas previously enumerated as to
+proportion, form, attitude, movement, depend on the study of the
+skeleton and muscles. It will thus be easiest and most advantageous
+to proceed in the following manner:—We will first of all study the
+skeleton, which will teach us the direction of the axis of each part
+of the limbs, the<span class="pagenum" id="Page_18">[18]</span> relative lengths and proportions of these portions,
+and the osseous parts which remain uncovered by the muscles, and show
+beneath the skin the shape and the mechanism of the articulations in
+their relation to movements and attitudes. We shall then study the
+muscles, and endeavour to know their shapes, at the same time that,
+we complete the knowledge we shall have acquired of attitudes and
+movements. In the third place, we will attempt the analysis of the
+expression of the passions and emotions; and the study of the muscles
+of the face, of which the mechanism in the movements of the physiognomy
+is so special that it would be inconvenient to attempt to treat it with
+that of the muscles of the trunk and limbs.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_19">[19]</span></p>
+
+  <div class="figcenter">
+  <img
+    class="p1" 
+    src="images/first_part.jpg"
+    alt="">
+  </div>
+</div>
+
+<hr class="r25">
+
+<p class="center sm">THE SKELETON, ARTICULATIONS, PROPORTIONS.</p>
+
+
+<hr class="r25">
+
+<h2>CHAPTER III.<br>
+<span class="subhed">OSTEOLOGY AND ARTHROLOGY IN GENERAL—NOMENCLATURE—VERTEBRAL COLUMN.</span></h2>
+
+<div class="blockquot">
+
+<p class="hangingindent"><i>Osteology</i> and <i>Arthrology</i>.—Anatomical
+nomenclature: median line; lateral parts; the meaning
+of terms.—Of the bones in general: long bones (shafts
+and extremities); flat bones (surfaces, borders); short
+bones.—Prominences (processes, spines); cavities
+and depressions of bone (fossæ, grooves).—Bone and
+cartilage.—The axial skeleton: the vertebral column.—The
+vertebræ (bodies, transverse processes, spinous processes,
+&amp;c.).—Cervical, Dorsal, Lumbar vertebræ.—Articulations of the
+vertebræ.—Movements of the spine.—Movements of the head (atlas
+and axis).—The curves of the vertebral column.—Relation of the
+vertebral column to the surface.—Proportions of the parts of
+the spine.</p>
+</div>
+
+
+<p>It is not necessary to emphasise further the importance of a study
+of the skeleton. By its means we obtain a knowledge of form and
+proportions; by a study of the several articulations we become
+acquainted with the complex mechanism by which the whole is knit
+together, and by which the movements of the various parts of the
+body occur. Further, the relations of the skeleton to the surface
+forms of different parts of the body are of fundamental importance.
+The science of <i>Osteology</i> is the study of bones (ὀστέον, bone;
+λόγος, description); <i>Arthrology</i> is the study of joints (ἅρθρον,
+a joint):<span class="pagenum" id="Page_22">[22]</span> <i>Myology</i> is the study of muscles (μυς; λογος). The
+bones are the levers of movement: the articulations represent the fixed
+points or fulcra of these levers; while the powers which produce motion
+are represented by the muscles.</p>
+
+  <div class="figcenter" id="i_020">
+     <img
+    class="p2"   
+    src="images/i_020.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 2.</p>
+     <p class="p0 sm center smcap">Front View of the Skeleton.</p>
+  </div>
+
+  <div class="figcenter" id="i_021">
+     <img
+    class="p2"   
+    src="images/i_021.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 3.</p>
+     <p class="p0 sm center smcap">Side View of the Skeleton.</p>
+  </div>
+
+<p>Before describing in detail the different parts of the skeleton, it
+is necessary to consider the method of nomenclature, so that by the
+employment of proper terms the subsequent descriptions may be more
+intelligible.</p>
+
+<p><span class="smcap">Nomenclature.</span>—In the description of the bones, as of
+other organs, we have to consider the relation of the portion under
+consideration to the rest of the body. The figure is always regarded as
+occupying the erect position, with the face, the palms of the hands,
+and the toes directed forward. Thus each bone, as well as the other
+organs or parts, will be found under one or other of two different
+conditions: either it is <i>median</i> in position, and a vertical
+plane passing through the longitudinal axis of the body divides it
+into two similar segments; or else it is <i>lateral</i> in position,
+and situated outside this median plane. As a type of the first class,
+we will take the <i>sternum</i>, or breast-bone (see Fig. <a href="#i_042">11</a>, p. 42).
+This is a central single bone; it has no fellow, and is composed of
+two symmetrical portions, one part on the right and one part on the
+left. As a type of the second class, we will take the <i>humerus</i>
+(Fig. <a href="#i_060">18</a>, p. 60), which is a bone situated at the side and one of a
+pair, inasmuch as there are two, one on the right and one on the left
+of the median plane. From these two examples it is easy to understand
+that for the description of each <i>single<span class="pagenum" id="Page_23">[23]</span> and symmetrical</i> bone
+it will be necessary to speak of anterior parts or surfaces directed
+towards the front of the body, of posterior parts (directed backwards),
+of lateral portions (right and left), and finally, of parts superior
+and inferior, looking upwards and downwards (in the case of the sternum
+a <i>superior</i> and <i>inferior extremity</i>): on the other hand,
+in the description of a paired and <i>non-symmetrical</i> bone, we
+shall also have to speak as heretofore of parts superior and inferior,
+anterior and posterior; but instead of two similar symmetrical
+portions, one on each side of an imaginary line, it has two dissimilar
+halves, of which the one looking towards the median plane—towards the
+axis of the body—is called the <i>internal</i> part, and the other,
+looking to the outer side (as away from the axis), is called the
+<i>external</i> part. It is necessary, for brevity and accuracy, to
+clearly comprehend the meaning of these terms in descriptive anatomy
+(anterior and posterior, internal and external, superior and inferior)
+which serve to show the relation of the parts to the skeleton as a
+whole.</p>
+
+<p>After this first division of bones into single and median, and into
+double and lateral, if we glance at the skeleton (Figs. <a href="#i_020">2</a>, <a href="#i_021">3</a>), it seems
+at first sight that the various bones present an infinite variety of
+shape, and defy classification or nomenclature; careful attention,
+however, will show us that they may be all included in one of the
+following three classes—viz., long bones, flat or broad bones, and
+short bones.</p>
+
+  <div class="figcenter" id="i_024" style="max-width: 517px">
+     <img
+    class="p2"   
+    src="images/i_024.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 4.</p>
+     <p class="p0 sm center"><span class="smcap">The Complete Skeleton</span> (in the attitude of “The Fighting
+Gladiator” of Agasias).</p>
+  </div>
+
+<p>The long bones, which usually act as the axes of the limbs
+(<i>e.g.</i>, the <i>humerus</i>, <i>femur</i>, <i>tibia</i>, &amp;c.),<span class="pagenum" id="Page_24">[24]</span>
+are composed of a central portion, cylindrical or prismatic in shape,
+called the <i>body</i>, <i>shaft</i>, or <i>diaphysis</i> (διαφύω,
+to be between), and of two extremities or <i>epiphyses</i> (ἐπιφύω,
+to be at the end), usually marked by protuberances and articular
+surfaces. The flat bones (<i>e.g.</i>, the <i>shoulder-blade</i> and
+the <i>hip bone</i>) are formed of osseous plates, on which are various
+<i>surfaces</i>, <i>borders</i>, and <i>angles</i>.<span class="pagenum" id="Page_25">[25]</span> Finally, the small
+bones, which are found in the vertebral column and in the extremities
+of the limbs, the hand and foot (<i>carpus</i> and <i>tarsus</i>),
+present a diversity of form in which cylindrical, cubical, and
+wedge-like shapes can be made out.</p>
+
+<p>Whether the bone be long, flat, or short, it presents prominences and
+depressions. The projecting portions of bone are called by various
+names—<i>tuberosities</i>, <i>protuberances</i>, <i>processes</i>,
+<i>apophyses</i>, <i>crests</i>, <i>spines</i>, <i>tubercles</i>. To
+some of these names is added an adjective, which shows, more or less
+exactly, the form of the process or projection. Thus we speak of a
+<i>spinous process</i>, <i>mastoid process</i> (μαστὸς, a nipple;
+εἶδος, form), <i>styloid process</i>, &amp;c. The depressions upon the
+bones are called by various names—<i>fossa</i>, <i>groove</i>,
+<i>foramen</i>, <i>sinus</i>, <i>canal</i>, <i>notch</i>,
+<i>cavity</i>, &amp;c. To these also are added names which indicate their
+shape, as the <i>digital fossa</i>, from its resemblance to the imprint
+of a finger; the <i>glenoid cavity</i> (γλήνη, cavity), the <i>cotyloid
+cavity</i> (χοτύλη, a basin); but more frequently still, the added
+adjective bears allusion to a connection of the cavity with certain
+organs, as the <i>bicipital groove</i>, that which contains the tendon
+of the biceps, or the <i>canine fossa</i>, in relation to the root of
+the canine tooth.</p>
+
+<p><i>Structure of Bone.</i>—Bone is characterised by its density,
+toughness and elasticity. If a long bone, such as the femur, is sawn in
+two lengthwise, its extremities are found to be composed of a delicate
+network of <i>cancellous</i>, or spongy bone, in the interstices of
+which marrow and blood are contained during life; the shaft of the
+bone is composed,<span class="pagenum" id="Page_26">[26]</span> for the most part, of a cylindrical tube of dense,
+ivory-like compact bone, which encloses the hollow medullary canal of
+the bone, also filled with marrow during life. The dense bone of the
+shaft is continuous with a thin sheet of hard bone, which covers over
+the spongy bone of the extremities.</p>
+
+<p>In the case of the flat and short bones, the structure is like that of
+the extremities of the long bones. The mass of the bone is composed of
+cancellous tissue, with a surrounding thinner envelope of compact bone.</p>
+
+<p>If a bone is burnt, it loses one-third in weight, becomes brittle,
+and loses its organic constituents, retaining its inorganic
+materials—chiefly calcium phosphate and calcium carbonate. If it
+is subjected to prolonged soaking in an acid such as hydrochloric
+acid, its inorganic salts are removed, it becomes soft and pliable,
+it loses two-thirds of its weight and retains only its organic
+materials—connective tissues. These in boiling produce glue.</p>
+
+<p>In certain situations bone is found in conjunction with a substance
+which differs from it in its elasticity, its want of rigidity (it is
+soft enough to be divided by the scalpel), and in its translucent
+colour. This substance is known by the name of cartilage. Thus the
+curved bones termed ribs are prolonged at their anterior extremities
+by a portion called the <i>costal cartilage</i>, which presents the
+same form as the ribs properly so called. The bones forming the freely
+movable joints (like the shoulder, hip and knee joints) are capped by
+thin layers of hyaline <i>articular cartilage</i>, which forms a pliant
+elastic cushion in relation to the articulation.</p>
+
+<p><span class="pagenum" id="Page_27">[27]</span></p>
+
+<p>Most of the bones, at the commencement of their formation, are
+constructed solely of cartilage, which is gradually transformed into
+bone as the animal grows by the deposition in it of lime salts; and
+this transformation of primitive cartilage into bone may be more or
+less complete according to the species or age of the animal. With
+advancing age the bones tend to become more and more calcified. Thus
+we find that in the skeletons of old people the costal and other
+cartilages may be more or less ossified.</p>
+
+<p><i>The Subdivisions of the Skeleton.</i>—The human skeleton is
+characterised by peculiarities due to the assumption of the erect
+position, the high development of the brain, and the possession of
+extraordinary manual dexterity. All these factors leave their impress
+on the bones of the skeleton, as may be seen by comparing the human
+skeleton with that of such a quadruped as the dog.</p>
+
+<p>The skeleton is subdivided into <i>axial</i> and <i>appendicular</i>
+parts. The axial skeleton includes the vertebral column, ribs and
+sternum, and the bones of the cranium and face. The <i>appendicular</i>
+skeleton comprises the bones of the limbs. In the following pages, for
+convenience of description, an account will be given of the vertebral
+column, sternum, and ribs first; of the limbs second; reserving to the
+last the account of the skeleton of the cranium and face.</p>
+
+<p><i>The Vertebral Column.</i>—The vertebral column (Figs. <a href="#i_028">5</a>, <a href="#i_033">8</a>) is
+composed of a number of bones named <i>vertebræ</i>, superimposed on
+one another, and partially separated from one another by a series of
+<i>intervertebral<span class="pagenum" id="Page_28">[28]</span> discs</i>. The column is subdivided into groups of
+vertebræ, by reason of its connections with other parts of the axial
+skeleton, or with the skeleton of the limbs.</p>
+
+  <div class="figcenter" id="i_028" style="max-width: 350px">
+     <img
+    class="p2"   
+    src="images/i_028.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 5.</p>
+     <p class="p0 sm"><span class="smcap">The Vertebral Column</span> (antero-lateral aspect).—1,
+the first cervical vertebra (atlas);—9, 9, its occipital
+articulating surfaces;—2, the second cervical vertebra, or
+axis;—13, its body;—4, seventh cervical;—5, 5, transverse
+processes of the ten first thoracic vertebræ;—8, 8, transverse
+processes of the lumbar vertebræ;—10, 11, 12, articular
+processes;—19, 19, bodies of the lumbar vertebræ;—20, the
+sacrum;—21, the coccyx.</p>
+  </div>
+
+<p>The <i>head</i> is poised on the upper end of the column, and causes
+the peculiarities, to be described later, in the first two vertebræ
+(<i>atlas</i> and <i>axis</i>). The attachment of the ribs to the sides
+of the vertebral column causes the separation of three regions: (1)
+<i>cervical</i>, belonging to the neck, and comprising seven vertebræ;
+(2) <i>thoracic</i> (or dorsal), belonging to the <i>thorax</i>,
+or chest, and comprising twelve vertebræ; and (3) <i>lumbar</i>,
+belonging to the loin, and comprising five vertebræ. The attachment
+of the hip bones to the sides of the succeeding vertebræ leads to the
+fusion of the next five vertebræ together, under the name of the <i>os
+sacrum</i>, which will be described along with the <i>hip bone</i> and
+<i>pelvis</i>. Finally, below the sacrum are four small, rudimentary
+vertebræ, known as the <i>coccyx</i>, forming the attenuated remains of
+a caudal appendage.</p>
+
+<p><span class="pagenum" id="Page_29">[29]</span></p>
+
+<p>There are thus, altogether, normally thirty-three vertebræ: seven
+cervical, twelve thoracic, five lumbar (constituting together
+twenty-four movable vertebræ); five sacral, and four coccygeal vertebræ
+(constituting nine fixed vertebræ, which help to form the pelvic basin).</p>
+
+  <div class="figcenter" id="i_029" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_029.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 6.</p>
+     <p class="p0 sm hangingindent"><span class="smcap">Outline of a Vertebra</span> (upper surface).—<i>0</i>,
+vertebral foramen;—1, spinous process;—2, body of
+vertebra;—3, 3, transverse process with articulating facets (4,
+4) for the tuberosity of the rib (see p. 30);—5, 5, superior
+articular processes;—6, 6, the parts which connect the body
+with the base of the transverse and articular processes;—7, 7,
+vertebral laminæ.</p>
+  </div>
+
+<p>The vertebral column is intended not only to form an axis for the
+rest of the skeleton, but also to serve as an attachment, direct or
+indirect, for all the other bony structures; it also forms a bony
+canal, within which the spinal marrow is contained. It is for this
+reason that each of the pieces which compose it, called a vertebra,
+is a sort of bony ring (Fig. <a href="#i_029">6</a>). The anterior portion of the ring is
+very thick, representing the segment of a cylinder, and is called the
+body of the vertebra (2, Fig. <a href="#i_029">6</a>); and the vertebral column, considered
+as the median column of support, is essentially constituted by the
+superposition of these vertebral bodies upon one another, separated
+by the intervertebral discs. Behind each vertebral body is an arch,
+the <i>neural arch</i>, which encloses the neural ring. The spinal
+or <i>neural canal</i> is formed by the combination and connection
+together of the neural rings. Each neural arch is comparatively
+slender, but it gives origin to certain projections or processes,
+three in<span class="pagenum" id="Page_30">[30]</span> number, on each side, of which one directed transversely
+outwards is called the <i>transverse process</i> (3, Fig. <a href="#i_029">6</a>). In the
+thoracic region these give partial attachment to the ribs. The other
+two—directed more or less vertically, one above, the other below—are
+called the <i>articular processes</i>, superior and inferior. These
+serve for uniting together the arches of adjoining vertebræ (5,
+5, Fig. <a href="#i_029">6</a>). Finally, the posterior portion of the neural arch is
+prolonged backwards as a protuberance, more or less pointed, called the
+<i>spinous process</i> (1, Fig. <a href="#i_029">6</a>).</p>
+
+<p>Such are the most important parts which we find in each vertebra, but
+they present particular characters according to the region to which
+each vertebra belongs. The description of the sacrum and the coccyx,
+which are formed of vertebræ welded together, and articulating with the
+hip bones, will be given with that of the pelvis.</p>
+
+<p>The more important features of the movable vertebræ which contribute
+to give to the whole column its general form are: (1) the size,
+particularly of the bodies, of the vertebræ; and (2) the characters of
+the transverse processes. The bodies of the vertebræ are smallest in
+the upper thoracic region, and increase in size upwards and downwards
+from the fourth thoracic vertebra. The bodies are largest and most
+prominent in the loin; in the neck the vertebræ are broad in the
+transverse diameter, but their antero-posterior diameters are less.
+The vertebral column is weakest in the upper thoracic and upper lumbar
+regions, and most mobile in the neck and thorax. Rotary power in the
+loin<span class="pagenum" id="Page_32">[32]</span> is practically prevented by the shape of the lumbar articular
+processes, which interlock the vertebral arches in this region.</p>
+
+  <div class="figcenter" id="i_031" style="max-width: 340px">
+     <img
+    class="p2"   
+    src="images/i_031.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 7.</p>
+     <p class="p0 sm center"><span class="smcap">The Movable Vertebræ.</span>—A, atlas (upper surface); B C, axis; D
+E, cervical vertebra; F G, thoracic vertebra; H I, lumbar vertebra.</p>
+  </div>
+
+<p>The <i>spinous processes</i> of the vertebræ, which project more
+or less obviously in the middle line beneath the skin in different
+regions, in the cervical region are short and bifid; in the thoracic
+region they are long, sloped downwards, and “bayonet-shaped”; in
+the lumbar region they are directed straight backwards, and are
+“hatchet-shaped.”</p>
+
+<p>Besides these general characters in each region there are certain
+vertebræ which demand special mention owing to the peculiarities of
+their shape. These are the first two and the last cervical.</p>
+
+<p>The <i>first cervical</i> vertebra (Fig. <a href="#i_031">7</a>, <span class="allsmcap">A</span>), called the
+<i>Atlas</i>, because as directly supporting the head, it has been
+compared to the giant Atlas, supposed by the ancients to support the
+heavens, is a bony ring with only transverse processes, and on the
+upper and lower aspects of its lateral portion, two pairs of articular
+surfaces; the superior articular surfaces are hollow oval surfaces
+which articulate with the convex condyles of the occipital bone; and by
+the <i>occipito-atlantoid</i> joints provide for flexion and extension
+of the head on the spinal column. The inferior articular surfaces are
+flat and directed downwards to articulate with the axis and form the
+<i>atlanto-axial</i> joint, which is responsible for the movement from
+side to side of the head upon the trunk. The <i>axis</i>, or second
+vertebra (Fig. <a href="#i_031">7</a>, <span class="allsmcap">B C</span>), is so called from the presence on the
+upper surface of its body of a tooth-like process, the odontoid process
+(ὀδοὺς, tooth; ἔιδος, form), which projects upwards in an osseofibrous<span class="pagenum" id="Page_33">[33]</span>
+ring formed by a transverse ligament in the anterior part of the ring
+of the atlas. Ligaments extend from this process to the occipital bone,
+and it forms a pivot round which the head <i>and</i> the atlas move in
+the lateral movements of the head upon the spinal column.</p>
+
+<p>In nodding the head the movement occurs primarily at the
+occipito-atlantoid joint; in shaking the head, the chief movement
+is between the atlas and axis. These functions, of no moment in the
+production of surface forms, are of too great an importance in respect
+of the articulations of the head and trunk to be omitted here.</p>
+
+  <div class="figcenter" id="i_033" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_033.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 8.</p>
+     <p class="p0 sm"><span class="smcap">Vertebral Column</span> (lateral view).—1 to 7, bodies of
+cervical vertebræ;—8 to 19, bodies of thoracic vertebræ;—20 to
+24, bodies of lumbar vertebræ;—A, A, spinous processes;—B, B,
+articular surfaces of transverse processes for the tuberosities
+of the ribs;—C, auricular surface of sacrum.</p>
+  </div>
+
+<p>The <i>seventh</i> cervical vertebra, or <i>vertebra prominens</i>, is
+so called because of the extraordinary length of its spinous process,
+which, except in very stout people, forms a projection easily visible
+beneath the skin; and this projection is also<span class="pagenum" id="Page_34">[34]</span> more conspicuous as
+it corresponds to that part of the neck where the trapezius muscle,
+represented only by a fibrous layer—not fleshy—forms a flat surface
+at the back of the neck. In the centre of this surface the projection
+of the seventh cervical spine appears on the level of a transverse line
+passing through the superior border of the shoulder (see Fig. <a href="#i_021">3</a>). It
+may be observed that when the model bends the head forward the spinous
+process of the seventh cervical becomes very prominent. It should also
+be noted that in the majority of cases the spinous processes of the
+<i>sixth cervical</i> and <i>first thoracic</i> vertebræ also give
+rise to superficial projections above and below that produced by the
+<i>vertebra prominens</i>.</p>
+
+<p>We have been disconnecting the vertebræ in order to account for
+the construction of the vertebral column; we must next see how the
+different vertebræ are placed one upon the other—how they articulate
+in such a manner as to form a column, not rigid, but elastic and
+curved. The vertebræ are placed one on each other so that the inferior
+articular processes of one fit exactly on to the superior articular
+processes of the next beneath, and thus throughout the series we see
+(Fig. <a href="#i_033">8</a>) that the bodies of the vertebræ are not in contact one with
+the other, the space which separates them being filled in the living
+subject by elastic fibrous discs. These <i>intervertebral discs</i> are
+very thick in the lumbar region, and become thinner in proportion as we
+ascend to the superior dorsal and cervical regions. They are thicker
+in the cervical and lumbar regions than in the thorax; and taken<span class="pagenum" id="Page_35">[35]</span>
+together they form one-seventh of the length of the spinal column.
+Being compressible and elastic, these fibrous discs give to the column,
+formed by the placing one on another of the bodies of the vertebræ, a
+certain degree of flexibility, whereas a column formed of bone alone
+would have been quite rigid.</p>
+
+<p>In addition to the intervertebral discs, a series of ligaments
+which join together the posterior portions of the neural arches
+(<i>laminæ</i>) is of great importance. Composed of yellow elastic
+tissue to a large extent, they are known as the <i>ligamenta
+subflava</i>. They consist of two short bands placed on each side of
+the root of the spinous process, uniting the inferior border of the
+lamina of one vertebra with the superior border of the lamina situated
+next below it.</p>
+
+<p>The <i>yellow</i> or <i>elastic</i> tissue which composes these
+ligaments is similar to a piece of india-rubber; it is elastic—that is
+to say, it is able to stretch, and to return again by its own reaction
+to its original size when the cause which extended it has ceased to
+act: so that each movement of flexion of the column in front results
+in moving the vertebræ on one another, at the same time stretching
+these elastic ligaments. When the anterior muscles of the trunk which
+accomplish this flexion cease to contract, it is not necessary, in
+order to straighten the column, that the posterior muscles of the
+back should come into play; the elasticity of the ligamenta subflava
+suffices for this, as they return to their original dimensions and draw
+together the vertebral laminæ. We may say, then, that there is at the
+posterior<span class="pagenum" id="Page_36">[36]</span> portion of the column within each vertebra a pair of small
+springs which keeps the column erect, so that the erect attitude of the
+trunk is maintained simply by the presence of the elastic ligaments;
+although more is required when a man supports upon his back any extra
+weight or burden.</p>
+
+<p><i>The Ligamentum Nuchæ</i> (paxwax) is a large and powerful
+ligament composed of yellow elastic tissue. It is highly developed
+in quadrupeds, and is attached between the spinous processes of the
+cervical vertebræ and the occipital crest, a vertical ridge on the back
+of the skull. In man it is a rudimentary structure (as the head is
+poised on top of the vertebral column) and forms a membranous partition
+separating and giving partial attachment to the muscles of either side
+at the back of the neck.</p>
+
+<p><i>Curves of the Vertebral Column.</i>—The vertebral column is subject
+to a slight lateral curvature, generally towards the right side. Its
+chief curves, however, are antero-posterior, and are four in number
+(Fig. <a href="#i_033">8</a>): two, the thoracic and sacral curves, concave forwards, are
+primitive embryonic curves; two, cervical and lumbar, convex forwards,
+are secondary in their origin. The convexity forwards of the cervical
+region is to be connected with the raising upwards of the head on the
+trunk; the convex lumbar curve is due to the straightening of the lower
+limb, which in the course of development is brought into line with the
+vertebral axis.</p>
+
+<p>These curves (except the pelvic or sacral curve) are to be associated
+with a difference in the thickness in front and behind of the vertebral
+bodies,<span class="pagenum" id="Page_37">[37]</span> and of the intervertebral discs in the different regions of
+the spine.</p>
+
+<p>In most animals the vertebral column has but two curves, one the
+cervical curve, which is convex inferiorly, the other the dorso-lumbar,
+which is concave inferiorly.</p>
+
+<p>We have now to examine the influence that the vertebral column has in
+moulding the external form of the body, and to see if the length of the
+column can be made use of for a system of proportion.</p>
+
+<p>It is evident, in the first place, that the posterior portions of
+the vertebræ only can affect the outline of the body, the anterior
+portions, the bodies of the vertebræ, being deeply hidden in the cavity
+of the thorax and abdomen. Therefore, in the skeleton the posterior
+surface of the vertebral column (Fig. <a href="#i_038">9</a>) presents itself under the
+aspect of a median crest, formed by a series of spinous processes,
+the <i>spinal crest</i>, on each side of which is a groove bounded
+laterally by the series of transverse processes (the <i>vertebral
+furrow</i>). In the living subject these grooves are filled up by
+powerful and thick muscles, which project in such a manner that in the
+erect position the back presents a furrow in the median line bounded
+on each side by these muscles, at the bottom of which furrow the
+bony structure of the vertebral column is shown only by a series of
+projections placed one beneath the other, like the beads of a necklace,
+each one being formed by the summit or free extremity of a spinous
+process. These projections are well seen in the thoracic region, in
+which the curvature of the column is convex backwards, and they show
+themselves still<span class="pagenum" id="Page_38">[38]</span> more clearly when the subject bends forward, and
+thereby increases this curvature. They are not visible in the cervical
+region, where the ligamentum nuchæ projects to the surface, and a bed
+of powerful muscles covers them; but we have seen that the seventh
+cervical, or <i>vertebra prominens</i>—along with the sixth also in
+many cases—is remarkable for the projection which its spinous process
+makes. Finally, in the lumbar region these projections are but little
+marked, the spinous processes here being short and terminated not by
+points, but by straight borders (Fig. <a href="#i_033">8</a>).</p>
+
+  <div class="figcenter" id="i_038" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_038.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 9.</p>
+     <p class="p0 sm"><span class="smcap">Vertebral Column</span> (posterior view).—1, 1, cervical
+transverse processes;—2, 2, thoracic transverse processes;—3,
+3, lumbar transverse processes;—7, 8, 9, 10, spinous
+processes;—11, 11, articular surfaces for occipital bone of
+skull;—12, odontoid process of the axis;—13, 14, sacrum and
+coccyx.</p>
+  </div>
+
+<p>The measurements of the vertebral column are useful, on the one hand,
+as absolute measurements of length and height, and, on the other hand,
+in giving the ratio of its length to the stature of the subject.
+The height of the vertebral column in the average adult man is from
+twenty-three to twenty-four inches, being five for the cervical region,
+eleven for the thoracic, and seven inches for the lumbar region. But as
+the length of the vertebral column does not serve as a common<span class="pagenum" id="Page_39">[39]</span> measure
+for the total height of the body or for its different parts, it cannot
+be used as the basis of a system of proportion. A German zoologist,
+Carus, has advanced the idea that the length of the column forms one
+third of the height; but this proposition is not exact. On the other
+hand, it is not easy to measure the column from the atlas as far as the
+last lumbar vertebra,<span class="pagenum" id="Page_40">[40]</span> without taking account of the sacrum and coccyx.
+It will be more frequently found that the length of the trunk, from the
+superior limit of the thorax to the inferior limit of the pelvis, gives
+a measurement more easy to take, and more useful for comparing the
+general proportions of the body.</p>
+
+  <div class="figcenter" id="i_039" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_039.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 10.</p>
+     <p class="p0 sm smcap center">Outline of the Back and Shoulders.</p>
+  </div>
+
+<p>It is enough to say here that the proportion of the vertebral column
+to the height varies according to age and sex, and according as the
+stature of the individual is very great or very little; the vertebral
+column is, in fact, in comparison with the height, longer in the infant
+and in the female than in the adult male; it is also much longer in
+proportion to the height in subjects of short stature than in tall
+people. The cause of difference of stature between men and women,
+infants and adults, long people and short, is principally due to the
+length of the lower extremities—a question which will be dealt with in
+a subsequent chapter.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_41">[41]</span></p>
+
+<h2>CHAPTER IV.<br>
+<span class="subhed">THE THORAX.</span></h2></div>
+
+<div class="blockquot">
+
+<p class="hangingindent">The Sternum: its three portions—manubrium, gladiolus,
+xiphoid appendage; position and direction of the sternum; its
+dimensions, absolute and relative.—The ribs; the true ribs,
+the false and floating ribs; the obliquity and curvature of the
+ribs.—Of the thorax in general; its posterior aspect, anterior
+aspect, and base.</p>
+</div>
+
+
+<p>We have already seen that that portion of the vertebral column which
+is formed by the seven cervical vertebræ is free, and forms of itself
+the bony structure of the <i>neck</i>. It is the same in the lumbar
+region, where the five vertebræ alone form the bony structure of the
+abdomen. The twelve thoracic vertebræ, however, corresponding to the
+upper two-thirds of the trunk, are in connection with the ribs and
+sternum, and constitute with these bones the osseous frame-work of the
+<i>thorax</i>.</p>
+
+<p><span class="smcap">The Sternum.</span>—In the front part of the thorax is the sternum,
+a bone in the middle line, single and symmetrical (Fig. <a href="#i_042">11</a>). This bone
+is, in quadrupeds, formed of a considerable number of separate bones
+jointed together in a linear series. In the human subject it consists
+of three separate parts, one superior, one in the middle, and one
+inferior, known respectively as the pre-sternum, meso-sternum, and
+meta-sternum. The whole bone has been compared in shape to a short
+Roman sword, of which the pre-sternum represents the handle,<span class="pagenum" id="Page_42">[42]</span> or
+<i>manubrium</i>; the meso-sternum, the longest piece, is the body, or
+<i>gladiolus</i>; and the meta-sternum, the pointed extremity of the
+sword, and usually tipped with cartilage, is the <i>ensiform</i> or
+<i>xiphoid</i> cartilage. Thus constituted, the sternum presents for
+our consideration an anterior surface, a posterior surface, two lateral
+borders, an upper and a lower extremity.</p>
+
+  <div class="figcenter" id="i_042" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_042.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 11.</p>
+     <p class="p0 sm"><span class="smcap">Thorax</span> (anterior view).—1, pre-sternum, or manubrium
+of sternum;—2, meso-sternum, or body;—3, meta-sternum, or
+xiphoid appendage;—4, body of first thoracic vertebra;—5,
+twelfth thoracic vertebra;—6 and 7, first and second ribs;—8,
+8, the true or sternal ribs;—9, 10, the floating ribs;—11,
+costal cartilages.</p>
+  </div>
+
+<p>The anterior surface is smooth, but the union of the manubrium with the
+body of the sternum is marked by a prominent transverse ridge (sternal
+angle), due to the difference in direction of the<span class="pagenum" id="Page_43">[43]</span> two pieces at their
+junction. This projecting angle is very remarkable in some subjects,
+and gives a clearly marked convex shape to the superior portion of the
+anterior surface of the thorax. The posterior surface of the bone,
+which it is not necessary for artists to study, is generally flat, and
+presents a returning angle corresponding to the projecting angle of the
+anterior surface.</p>
+
+<p>The superior extremity of the sternum, forming the broader portion of
+the bone, is marked by three notches, or depressions: two lateral,
+one on each side, articulating with the inner end of the clavicle,
+and one in the middle called the suprasternal, or episternal, notch.
+This notch, which is easily discerned on the living model, forms the
+inferior border of the deep depression situated at the lower part of
+the front of the neck. Its depth is still further increased by the
+inner ends of the clavicles and by the sterno-cleido-mastoid muscles on
+either side.</p>
+
+<p>The inferior extremity of the sternum is formed by the meta-sternum, or
+xiphoid appendage, which remains very frequently in the cartilaginous
+state, in the form of a plate, thin and tapering. In shape and
+direction it is very variable, being sometimes pointed, rounded, or
+bifurcated. It may be situated in a plane corresponding to that of the
+body of the sternum, or it may be placed obliquely or project forwards
+or backwards. In a case where it projects in front it may cause a
+slight elevation of the skin of the region of the pit of the stomach,
+or epigastrium; but it is a detail of form so irregular that it is not
+worth reproducing, except in the<span class="pagenum" id="Page_44">[44]</span> representation of violent muscular
+exertion or extreme attenuation.</p>
+
+<p>The lateral borders of the sternum are not vertical, but concave. The
+sternum is narrowest at the manubrio-sternal junction, the manubrium
+increasing in size towards its upper end, and the gladiolus, or body
+of the bone, enlarging towards its inferior part. Each lateral border
+is marked by seven small notches, or depressions, for the reception of
+the anterior extremity of each of the cartilages of the first seven
+ribs. The highest of these depressions is situated on the border of
+the manubrium just below the clavicular articular surface; the second
+depression is situated opposite the manubrio-sternal junction, partly
+on the pre-sternum, partly on the meso-sternum; those following are
+situated on the edge of the body of the bone, or meso-sternum, and
+the spaces between the depressions become smaller as they approach
+its lower extremity, so that the last depressions for the sixth and
+seventh costal cartilages are almost fused into one. The seventh costal
+cartilage is usually attached opposite the sterno-xiphoid junction, and
+is thus connected with both meso-sternum and meta-sternum.</p>
+
+<p>It is necessary also to determine the exact position and direction
+of the sternum in relation to the other parts of the thorax, in the
+complete skeleton. The direction of the sternum is not vertical, but
+very oblique; it forms an angle of fifteen to twenty degrees, with a
+vertical line passing through the inferior extremity (Fig. <a href="#i_045">12</a>), and
+an angle of severity to seventy-five<span class="pagenum" id="Page_45">[45]</span> degrees, with a horizontal line
+passing through the same extremity (Fig. <a href="#i_045">12</a>). The manubrium is more
+oblique than the body of the sternum, and the body of the sternum than
+the xiphoid cartilage. Such is the direction of the sternum in the
+male; in the female it is less oblique, and approaches the vertical—a
+disposition which artists are prone to exaggerate by giving a more
+rounded form to the superior portion of the thorax in the female.</p>
+
+  <div class="figcenter" id="i_045" style="max-width: 335px">
+     <img
+    class="p2"   
+    src="images/i_045.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 12.</p>
+     <p class="p0 sm center smcap">Relations of the Sternum to the Vertebral Column.</p>
+  </div>
+
+<p>To compare the relations of the sternum with the rest of the thorax, it
+is necessary further to determine the level of the parts corresponding
+to the two extremities in relation to the vertebral column. The upper
+end of the sternum does not correspond to the first thoracic vertebra,
+but rather to the disc which separates the second and third, so that
+the horizontal plane passing through the superior extremity of the
+sternum strikes the second thoracic vertebra at its lower part (Fig.
+<a href="#i_045">12</a>). The horizontal plane passing through the lower end of<span class="pagenum" id="Page_46">[46]</span> the sternum
+strikes the tenth thoracic vertebra; so that, viewing the thorax in
+profile, the sternum is seen to project between the second and eleventh
+vertebræ. The exact level of the bone varies with the movements of the
+chest wall in respiration.</p>
+
+<p>The average length of the sternum in the adult man is eight inches.
+The pre-sternum, or manubrium, is usually about half as long as the
+meso-sternum, or body of the bone.</p>
+
+<p>The most important measurement, however, is the length of the sternum
+<i>without the xiphoid appendage</i>. A measurement equivalent to
+the length of the sternum is found in various parts of the skeleton,
+which for the most part are adjacent to the sternum, and the sternal
+length may be taken as a common measure for constructing a correctly
+proportioned torso.</p>
+
+<p>As a fact, this measure of the length of the manubrium and body of the
+sternum is equal to (1) the clavicle, to (2) the vertebral border of
+the shoulder-blade, and to (3) the distance which separates the two
+shoulder-blades in the figure when the arms are hanging by the side;
+further, the length of the sternum is equal to (4) the length of the
+hand without the third phalanx of the middle finger.</p>
+
+<p><span class="smcap">The Ribs.</span>—The thoracic part of the vertebral column and the
+sternum being known, it is easy to understand the arrangement of the
+parts which complete the thorax. These parts are the ribs and costal
+cartilages, arranged somewhat like the hoops of a cask, proceeding
+from the vertebral column to the sides of the sternum; the ribs
+articulate posteriorly with the vertebral column, and are connected<span class="pagenum" id="Page_47">[47]</span>
+anteriorly to the sternum or to one another by the costal cartilages.
+The ribs are twelve in number on each side. They are known as first,
+second, and third ribs, etc., counting from above downwards; the
+first seven are the <i>true ribs</i>, or <i>sternal</i> ribs, which
+have their costal cartilages directly joined to the sternum; the next
+three (eighth, ninth, and tenth) ribs are the <i>vertebro-costal</i>
+ribs, as the costal cartilage of each articulates with the cartilage
+of the preceding rib; the last two, the eleventh and twelfth, are
+the <i>false</i>, <i>floating</i> or <i>vertebral</i> ribs: they are
+remarkable for their shortness; they are provided at their extremities
+with only rudimentary cartilages, which are pointed, and project by
+free extremities among the muscles of the walls of the abdomen.</p>
+
+<p>In a general sense the ribs are long bones, presenting an external
+surface and an internal surface, a superior border and an inferior
+border. They are not horizontal, but oblique, from above downwards and
+from behind forwards: so that the anterior extremity of a rib is always
+placed on a lower level than its posterior extremity.</p>
+
+<p>A typical rib possesses three curves. It is bent from behind forwards
+in a downward direction; it is bent like the hoop of a cask in order
+to surround the thorax, and presents, therefore, a curve similar to
+that of a scroll, of which the convexity is turned outwards and the
+concavity inwards; and, again, it is twisted upon itself as if the
+anterior extremity had been forcibly carried inwards by a movement
+of rotation upon its own axis. This curvature of torsion makes the
+surface, which is really external<span class="pagenum" id="Page_48">[48]</span> in the central portion of the rib,
+become a superior surface in the anterior portion. In order to have a
+good idea of the torsion of the ribs it is necessary to take a single
+rib and place it on a horizontal surface, such as a table; it will be
+then seen that, instead of its being in contact through its entire
+extent with the flat surface, it touches it only at two points, as if
+it formed a half-hoop of a cask to which a slight spiral twist had been
+given.</p>
+
+<p>The ribs vary much in length, in order to correspond to the ovoid shape
+of the thorax; their length increases from the first to the eighth,
+which is the longest, and corresponds to the largest part of the
+thorax; and it gradually diminishes from the eighth to the twelfth.</p>
+
+<p>A typical rib (Fig. <a href="#i_049">13</a>) consists of the following portions, an
+indication of which is useful for the study of the shape of the thorax.
+The posterior extremity is slightly raised, and constitutes the head
+of the rib. It is shaped like a wedge, and articulates with the bodies
+of two vertebræ as a rule, and it is received, precisely like a wedge,
+into the space which separates the bodies of these vertebræ; so that it
+is in contact by the summit of the wedge with the intervertebral disc,
+and by the surfaces of the wedge with the vertebra which is situated
+above and that which is situated below the disc. Beyond the head, the
+rib presents a portion thin and compressed from before backwards,
+called the <i>neck</i> of the rib, which is placed in front of the
+transverse process of the vertebra corresponding to it.</p>
+
+<p>At the external extremity of the neck is a slight enlargement called
+the <i>tubercle</i>, which corresponds<span class="pagenum" id="Page_49">[49]</span> to the level of the external
+extremity of the transverse process of the vertebra, and which
+articulates with the corresponding transverse process (Fig. <a href="#i_031">7</a>, <span class="allsmcap">F
+G</span>). By means of the connections of the head with the bodies of the
+vertebræ, and of the tubercle of the rib with the transverse process of
+the thoracic vertebra which corresponds to it, the posterior end of the
+rib moves on these joints as on a fulcrum, in the act of respiration;
+the chest cavity being enlarged by the uplifting of the shaft of the
+rib and by the eversion of the rib simultaneously.</p>
+
+  <div class="figcenter" id="i_049">
+     <img
+    class="p2"   
+    src="images/i_049.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 13.—A Typical Rib.</p>
+  </div>
+
+<p>Passing on from the tubercle, the <i>shaft</i> of the rib is formed of
+a bar of bone, which at first is directed outwards and backwards (Fig.
+<a href="#i_049">13</a>); then, after travelling some distance, it bends abruptly, so as to
+be directed forward, describing the characteristic curve of the rib. We
+give to this bend the name of the <i>angle</i> of the rib. The series
+of the angles of the ribs shows, upon the posterior aspect of the
+thorax, a line plainly visible, curved, with its convexity outwards,
+and having its summit at the level of the eighth rib, which is the
+longest, and upon which a relatively<span class="pagenum" id="Page_50">[50]</span> greater distance separates the
+angle from the tubercle.</p>
+
+  <div class="figcenter" id="i_050" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_050.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 14.</p>
+     <p class="p0 sm"><span class="smcap">Thorax</span> (posterior view).—1, 1, spinous processes of
+the thoracic vertebræ;—2, 2, vertebral laminæ;—3, 3, series
+of transverse processes;—4, 4, the parts of the ribs included
+between the tuberosities and the angles of the ribs;—5, 5,
+angles of the ribs, becoming more distant from the vertebral
+column as the rib becomes more inferior.</p>
+  </div>
+
+<p>Such are the characters of ribs in general. For the peculiar characters
+of the several ribs, after we have spoken of the last two ribs, it
+will suffice to note the shortness of the upper ribs, and principally
+of the first, which is flattened from above downward. In other words,
+it is curved along the borders, and not along the surfaces, and it
+does not present any twist. The last two ribs, besides being the
+shortest as a rule (excepting the first rib), are peculiar in their
+straightness and in the rudimentary nature of<span class="pagenum" id="Page_51">[51]</span> the angles; they further
+have no articulation with the transverse processes of the corresponding
+vertebræ.</p>
+
+<p>The <i>costal cartilages</i> are attached to the extremities of the
+ribs in front: these cartilages, in proceeding to join the sternum,
+follow a course more or less oblique, so that the cartilage of the
+first rib is oblique from above downwards, and from without inwards;
+and those following present the same obliquity (Fig. <a href="#i_042">11</a>), which
+becomes more accentuated in the cartilages lower down. The spaces
+which separate these cartilages are wide above, especially between the
+cartilages of the three first ribs, and become narrower towards the
+lower part of the chest.</p>
+
+<p><i>The Thorax as a Whole.</i>—The thorax, the constituent parts of
+which we have just examined, forms a kind of truncated cone, with its
+base below and its apex above; but, from an artist’s point of view as
+to form, it is not necessary to take this into account, as the shape of
+the summit of the thorax is completely changed by the addition of the
+osseous girdle constituted by the clavicle and shoulder-blade.</p>
+
+<p>We limit ourselves, then, to a rapid view of the posterior surface, the
+anterior surface, and the base of the thorax.</p>
+
+<p>The posterior surface (Fig. <a href="#i_050">14</a>) presents upon the skeleton, in the
+median line, the series of spinous processes, and on each side, first a
+row of transverse processes and then the angles of the ribs. As already
+explained (p. 37), respecting these several details, the summits of the
+spinous processes, although just<span class="pagenum" id="Page_52">[52]</span> under the skin, are scarcely visible,
+especially in a very muscular subject.</p>
+
+<p>On the anterior surface of the thorax (Figs. <a href="#i_042">11</a>, <a href="#i_053">15</a>), in a muscular
+subject, the osseous details do not show on the external figure, with
+the exception of the <i>episternal</i> or <i>suprasternal notch</i>
+(p. 43), and the inner ends of the clavicles, which are more or less
+visible. The great pectoral muscles form on each side a large fleshy
+surface, and the median line of separation of these muscles is marked
+by a narrow depression corresponding to the central portion of the
+sternum, the only region where this bone becomes subcutaneous; but
+in less muscular subjects, in the aged and in thin children, all the
+details of the thoracic frame-work show beneath the skin, and clearly
+reveal the forms of the costal cartilages with their obliquities, the
+thin intervals of separation (<i>intercostal spaces</i>) becoming
+narrower as we get lower down. Moreover, especially in infants, the
+articulation of the cartilages with the sternum, and the articulation
+of the cartilages with the anterior extremities of the ribs, are shown
+by a double row of nodules, as the points of junction of the osseous
+and cartilaginous portions are slightly elevated. We find therefore
+a series of <i>chondro-sternal</i> nodules (χόνδρος, cartilage)
+marking the borders of the sternum, and, on the outer side, a series
+of <i>chondro-costal</i> nodules, marking the line of junction of the
+ribs with the cartilages. This chondro-costal line descends obliquely
+from within outwards; so that, above, it is very near the sternum,
+owing to the shortness of the cartilage of the first rib, and, below,
+it is withdrawn from the sternum owing to the<span class="pagenum" id="Page_53">[53]</span> greater length of the
+cartilages of the ninth and tenth ribs.</p>
+
+  <div class="figcenter" id="i_053" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_053.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 15.</p>
+     <p class="p0 sm center smcap">Front View of the Chest and Abdomen.</p>
+  </div>
+
+<p>The <i>base</i>, or <i>inferior circumference</i>, of the thorax is
+continuous, without distinct limits upon the living subject, with the
+abdominal wall behind and laterally; but in front this circumference
+presents a depression in the form of an inverted <img src="images/thick_v.jpg" alt=""
+style="height:1em;  padding:0 0em 0 0em;">
+with the mouth looking downwards (Fig. <a href="#i_042">11</a>); this depression, limited on
+both sides by the cartilages of the lower six ribs, and corresponding
+at its apex to the junction of the body of the sternum with its
+costo-xiphoid appendage, shows in the living subject a depression of
+the same form, called the pit of the stomach, or <i>epigastrium</i>
+(ἐπὶ, upon; γαστήρ, stomach). Upon the dead body, or upon a model in a
+state of repose, the outlines of the pit may be compared to a pointed
+arch; but<span class="pagenum" id="Page_54">[54]</span> when the model makes a violent effort, as in taking a deep
+inspiration, the elevation of the ribs spreads the cartilages of the
+false ribs from the median line, and the pointed arch in question
+shortens and tends to take a rounded form. On the other hand, in
+very muscular subjects, the great anterior muscles of the abdomen
+are sufficiently thick at their superior parts, where they cover
+the cartilages of the false ribs, to add their shape to that of the
+cartilages, and to give to the epigastric region a more rounded form.
+It is this form of a rounded arch that the Greek sculptors have adopted
+almost exclusively, and this choice we find justified to some extent
+in the fact that they had for their models very muscular athletes,
+whom they studied during the wrestling-matches of the gymnasium, when
+efforts which dilated the thorax most powerfully were to be observed.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_55">[55]</span></p>
+
+<h2>CHAPTER V.<br>
+<span class="subhed">THE SHOULDER.</span></h2></div>
+
+<div class="blockquot">
+
+<p class="hangingindent">The bones of the shoulder.—The clavicle: its shaft and
+extremities, sternal and acromial: its proportions.—The
+shoulder-blade: its situation and relations.—The spine
+of the scapula: acromion: coracoid process: glenoid
+cavity.—Proportions of the scapula: the distance which
+separates the right from the left scapula.—The upper portion
+of the humerus: the anatomical neck, the surgical neck:
+the articular head: the tuberosities.—The shoulder-joint:
+its movements: the increase of mobility assured by the
+acromio-clavicular and sterno-clavicular articulations the
+to-and-fro motion of the scapula: the importance of this
+mechanism with regard to external form.</p>
+</div>
+
+
+<p>The shoulder is formed of three bones, of which one is situated in the
+front, the <i>collar-bone</i>, or <i>clavicle</i>; a second is behind,
+the <i>shoulder-blade</i>, or <i>scapula</i>; and a third is placed
+externally, the upper part of the <i>arm-bone</i>, or <i>humerus</i>.</p>
+
+<p>The <i>clavicle</i> (<i>clavicula</i>, diminutive of <i>clavis</i>,
+a key) is a long bone, placed horizontally at the junction of neck
+and chest. It connects the breast-bone with the shoulder-blade; and
+the two clavicles are separated in the middle line by the upper end
+of the manubrium, or pre-sternum (episternal or suprasternal notch).
+Its form is that of an italic ∫—that is to say, it describes in a
+horizontal plane two curves, the internal portion being convex in
+front, and the outer part convex behind (Fig. <a href="#i_056">16</a>). It consists of a
+shaft and two extremities: the <i>shaft</i>, flattened from above down,
+presents a smooth <i>superior surface</i>, which in the model shows
+very clearly beneath the skin, and a rough <i>inferior surface</i><span class="pagenum" id="Page_56">[56]</span>
+for the attachment of a muscle (subclavius), and for the attachment of
+ligaments connecting it with the first rib internally, and with the
+coracoid process of the scapula externally (see below); it possesses
+a <i>posterior</i> and an <i>anterior border</i>, thick and curved:
+an <i>internal, sternal extremity</i>, thick and triangular, which
+articulates with the corresponding lateral facet on the manubrium of
+the sternum: and an <i>outer, acromial extremity</i>, flattened and
+presenting an oval articular surface for articulation with the acromion
+process of the scapula. The clavicle thus serves to connect the scapula
+to the trunk, and by the articulations of its two extremities it
+increases, as we shall see, the mobility of the shoulder-joint. We find
+that the clavicle, which is almost horizontal when the arms are hanging
+in an attitude of repose beside the trunk, becomes oblique in direction
+when the arms are moved upward and forward, or upward and backward.
+The length of the clavicle, as we have already said (p. 46), should be
+equal to that of the sternum without the xiphoid appendix.</p>
+
+  <div class="figcenter" id="i_056" style="max-width: 457px">
+     <img
+    class="p2"   
+    src="images/i_056.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 16.</p>
+     <p class="p0 sm"><span class="smcap">Right Clavicle: Upper Surface.</span>—1, body of
+clavicle;—2, 3, inner or sternal extremity;—4, 5, outer or
+acromial extremity.</p>
+  </div>
+
+<p>The <i>shoulder-blade</i>, or <i>scapula</i>, is a flat, triangular
+bone, and consists of a bony plate very thin at certain points, and
+thickened only along its borders. It is placed on the lateral and
+posterior aspect of the thorax, and corresponds at its upper border
+to the second rib: its lower end reaches to the seventh or eighth
+rib. It is attached by a joint called the<span class="pagenum" id="Page_57">[57]</span> <i>acromio-clavicular
+articulation</i>, which can be felt beneath the skin, to the external
+extremity of the clavicle. As this joint is the only ligamentous
+connection of the scapula with the trunk, the bone is capable of great
+freedom of movement.</p>
+
+  <div class="figcenter" id="i_057" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_057.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 17.</p>
+     <p class="p0 sm"><span class="smcap">Shoulder-blade: Posterior Surface.</span>—1, supra-spinous
+fossa;—2, infra-spinous fossa;—3, superior border with
+supra-scapular notch (4);—5, external or axillary border
+with impression for attachment (8) of the long head of the
+triceps;—6, glenoid cavity;—7, inferior angle;—9, internal or
+vertebral border;—10 and 11, spine of shoulder-blade extending
+into acromion process (12);—14, coracoid process.</p>
+  </div>
+
+<p>The shoulder-blade is described as possessing two surfaces, three
+borders, three processes, and three angles. The <i>posterior
+surface</i>, free and visible throughout its entire extent upon the
+mounted skeleton, is divided into two unequal portions—the upper one,
+the smaller (<i>supra-spinous fossa</i>) and the lower one, the larger
+(<i>infra-spinous fossa</i>)—by a bony crest, called the <i>spine of
+the scapula</i> (10, 11, Fig. <a href="#i_057">17</a>), which traverses the bone obliquely
+from within upwards and outwards. It becomes more and more prominent
+externally, and is afterwards prolonged into a free process, broad
+and flat, which forms the most elevated and external part of the
+skeleton of the shoulder (12, Fig. <a href="#i_057">17</a>), and is known by the name of
+the <i>acromion process</i> (ἃχρος, summit;<span class="pagenum" id="Page_58">[58]</span> ὦμος, the shoulder). It
+is on the internal or anterior border of this acromion process that
+the small oval facet is found, by which the scapula articulates with
+the outer extremity of the clavicle by the <i>acromio-clavicular</i>
+articulation. The fossa above the spine of the scapula is the
+<i>supra-spinous fossa</i> (1, Fig. <a href="#i_057">17</a>), and the larger space below
+the spine is called the <i>infra-spinous fossa</i> (2, Fig. <a href="#i_057">17</a>). The
+<i>anterior surface</i> of the scapula has received the name of the
+<i>subscapular fossa</i>. It is directed forwards and inwards, and is
+separated from the ribs and armpit by large muscles. It is but little
+visible in the articulated skeleton.</p>
+
+<p>Of the three borders of the scapula, one is <i>superior</i> and
+horizontal; it is the shortest of the three. The second is internal and
+vertical, parallel to the series of spinous processes of the vertebræ;
+to this is given the name of the <i>vertebral border</i>. The third,
+or outer border, is oblique, and is directed downwards and backwards;
+it corresponds to the region of the armpit, and has received the name
+of the <i>axillary border</i>. It is particularly to be noticed that
+the vertebral border is thin; the axillary border, on the contrary,
+is thick, and presents towards its superior limit a rough space, just
+below the glenoid fossa, for the attachment of the long head of the
+triceps muscle (8, Fig. <a href="#i_057">17</a>). The superior border is remarkable for the
+presence at its outer extremity of a stout process which projects at
+first upwards, and is afterwards bent outwards upon itself like a bent
+finger. It has been likened to the beak of a crow, and has received
+the name of the <i>coracoid process</i> (κὸραξ, a crow; εἷδος, form).
+The coracoid process<span class="pagenum" id="Page_59">[59]</span> (14, Fig. <a href="#i_057">17</a>) is placed in front and on the
+inner side of the acromion, and the two together form an arch over
+the shoulder-joint, called the <i>coraco-acromial arch</i>, which is
+completed by a fibrous band proceeding from one process to the other,
+and called the <i>coraco-acromial ligament</i>. The position of the
+coracoid process should be particularly noted in relation to the
+clavicle. It underlies the outer part of the clavicle, from which two
+important ligaments (<i>conoid and trapezoid ligaments</i>) descend to
+be attached to its upper surface. These ligaments serve the purpose
+of slinging the scapula up to the under surface of the clavicle. Of
+the three angles of the scapula, one only—the superior external
+angle, which is situated beneath the coraco-acromial arch—deserves
+a particular description; it is very thick, and becomes enlarged to
+form an articular surface (6, Fig. 057), which is directed outwards and
+forwards, and articulates with the head of the humerus. This surface
+is pear-shaped and is slightly hollowed out, and bears the name of the
+<i>glenoid cavity</i>. It is much less extensive than the articular
+head of the humerus, along with which it forms the shoulder-joint.</p>
+
+<p>In regard to the relative proportions of the scapula, it may be noted
+that the length of the vertebral border is equal to the length of the
+clavicle, and equal also to the distance which separates the scapulæ
+behind, when the vertebral borders are vertical, which is the case when
+the arms are hanging beside the body in a position of relaxation.</p>
+
+<p>The movements of the shoulder-blade, and their effects on external
+form, will be studied in relation<span class="pagenum" id="Page_60">[60]</span> to the articulation of the scapula
+with the humerus, the <i>scapulo-humeral</i> articulation, or
+shoulder-joint. We must now pass on to describe the upper portion of
+the bone of the arm.</p>
+
+  <div class="figcenter" id="i_060" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_060.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 18.</p>
+     <p class="p0 sm"><span class="smcap">Left Humerus</span> (anterior surface): 1, body of the
+bone;—2, articular head;—3, anatomical neck;—4, great
+tuberosity;—5, lesser tuberosity;—6, bicipital groove;—7,
+deltoid impression;—11, capitellum;—12, trochlea;—13,
+external supra-condyloid ridge;—14, condyles;—16, internal
+supra-condyloid ridge;—17, coronoid fossa.</p>
+  </div>
+
+<p>The arm bone, or <i>humerus</i>, is one of the long bones, and is
+composed of a shaft, prismatic or nearly cylindrical in form, and
+of two enlarged extremities, one inferior, which takes part in the
+articulation of the elbow; the other superior, which takes part in the
+articulation of the shoulder. We will only concern ourselves for the
+present with the superior extremity.</p>
+
+<p><i>The superior extremity</i> of the humerus is large and spherical.
+It is continuous with the body of the bone by a cylindrical neck,
+called the <i>surgical neck</i> of the humerus. This extremity is
+traversed by a circular groove, oblique from above downwards, and
+from without inwards, called the <i>anatomical neck</i> (3, Fig.
+<a href="#i_060">18</a>). This is well marked, and divides the sphere into two parts; the
+one, situated above, and internal to the anatomical neck, is very
+regularly rounded, smooth, covered over by a layer of cartilage, and
+is called the <i>head</i> of the humerus (2, Fig. <a href="#i_060">18</a>); it is normally
+in contact<span class="pagenum" id="Page_61">[61]</span> with the glenoid cavity of the shoulder-blade, in which
+it glides in the movements of the arm; the other part of the head,
+situated below, and external to the anatomical neck, is rough, and
+divided into two tuberosities by a vertical groove, which is prolonged
+as far as the upper part of the body of the bone, and which, from its
+serving to accommodate the long tendon of the biceps, has received
+the name of the <i>bicipital groove</i> (6, Fig. <a href="#i_060">18</a>). The tuberosity
+situated on the outer side of the bicipital groove is large, and is
+called the <i>great tuberosity</i> (4, Fig. <a href="#i_060">18</a>); it presents three
+small surfaces which receive the insertions of the deep muscles of
+the shoulder—supraspinatus, infraspinatus, and teres minor muscles.
+The tuberosity situated on the front of the bone, and internal to the
+bicipital groove, is smaller. It is called the <i>small tuberosity</i>
+of the humerus (5, Fig. <a href="#i_060">18</a>), and gives attachment to one muscle only,
+the subscapularis.</p>
+
+<p><span class="smcap">The Shoulder-joint.</span>—The articulation of the shoulder,
+or <i>scapulo-humeral</i> articulation, may serve as a type of
+articulations in general. It is necessary in each articulation to
+consider how the shapes of the bony surfaces in contact correspond
+to each other. From this we should be able to deduce the nature of
+the movements permitted by the articulation. It is also necessary to
+consider the disposition of the ligaments; that is to say, of the
+fibrous bands which proceed from one bone to the other, and from these
+we can deduce the limits of the movements of which the joint may be
+capable.</p>
+
+<p><span class="pagenum" id="Page_62">[62]</span></p>
+
+<p>The scapulo-humeral articulation is a ball-and-socket joint, formed by
+the glenoid cavity of the shoulder-blade and the head of the humerus.</p>
+
+  <div class="figcenter" id="i_062" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_062.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 19.</p>
+     <p class="p0 sm"><span class="smcap">Ligaments of Shoulder, with Scapula, Clavicle, and
+Humerus.</span>—1, Acromio-clavicular ligament;—2,
+coraco-clavicular ligament;—3, coraco-acromial ligament;—4,
+supra-scapular ligament;—5, capsule of shoulder-joint;—6,
+coraco-humeral ligament;—7, tendon of biceps (long head).</p>
+  </div>
+
+<p>Such an arrangement of surfaces in contact with one another permits the
+head to glide in all directions within the cavity, and consequently the
+upper limb can be moved in all directions: forwards; backwards; inwards
+(adduction); outwards (abduction); upwards and downwards. The head of
+the humerus can also be rotated on the glenoid cavity, either inwards
+or outwards.</p>
+
+<p>The ligamentous covering of the joint is formed by a fibrous capsule,
+which is attached on one side to the margin of the glenoid cavity, and
+on the other side to the anatomical neck of the humerus (5, Fig. <a href="#i_062">19</a>).</p>
+
+<p>This ligamentous capsule is sufficiently loose to allow the head of the
+humerus great freedom of movement within the glenoid cavity, without
+any part of the capsule being put on the stretch, and thus stopping its
+movement. Thus the movement of the arm forwards is very extensive, as
+are those<span class="pagenum" id="Page_63">[63]</span> backwards and directly inwards, this last being checked only
+by the meeting of the arm with the lateral surface of the trunk. But
+the movement of abduction, or of elevation outwards, becomes difficult
+when the arm approaches the horizontal; here an arrangement comes into
+play which is of great importance, the study of which shows us that the
+upper limb, besides the mobility which belongs to the shoulder-joint
+proper (scapulo-humeral articulation), derives an increase of mobility
+from the articulations of the shoulder-blade with the clavicle, and of
+the clavicle with the sternum.</p>
+
+<p>When we apply a humerus to the glenoid fossa of the scapula in such
+a manner as to draw the arm outwards, we observe that at the moment
+when the humerus attains the horizontal position, the tuberosities
+touch the coraco-acromial arch which surmounts the glenoid cavity, and
+which is completed by the coraco-acromial ligament (3, Fig. <a href="#i_062">19</a>); in
+the complete subject, in the living man, when the arm is elevated in
+carrying it outwards, the same effect of meeting and, so to speak, of
+contact between the tuberosities of the humerus and the acromial arch
+is produced, with this result—that the arm, once horizontal, is with
+difficulty raised higher by the simple play of the scapulo-humeral
+articulation—that is to say, by the gliding of the head of the humerus
+in the glenoid cavity. But now a new source of mobility is employed, a
+new articulation is brought into play—that of the acromio-clavicular
+joint. The entire scapula moves round the extremity of the clavicle;
+its inferior angle is carried forward; its external angle—that<span class="pagenum" id="Page_64">[64]</span> is
+to say, the glenoid cavity with the coraco-acromial arch—is carried
+upwards, and the movement of elevation of the arm is then continued by
+the play of the shoulder-blade.</p>
+
+  <div class="figcenter" id="i_064" style="max-width: 317px">
+     <img
+    class="p2"   
+    src="images/i_064.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 20.</p>
+     <p class="p0 sm center smcap">Outline of Shoulder with the Arm Raised.</p>
+  </div>
+
+<p>As the result is an important change of shape in the shoulder, we ought
+to particularly examine the shoulder in the region of the back, upon
+a model in which the arm is raised above the horizontal position. The
+point of the shoulder is raised, and as this elevation is accompanied
+by a movement of the shoulder-blade, the vertebral border of this bone
+does not remain parallel to the spinal column, but while it approaches
+closer to it at its upper end, it is drawn further away at its lower
+end, and is obliquely directed from above downwards and outwards (Fig.
+<a href="#i_064">20</a>). The inferior angle becomes prominent in the lower part of the
+armpit, as we may observe in a subject with the arms folded, and shows
+in a striking manner on a dead crucified body. If the elevation of the
+arm approaches the vertical, the vertebral border of the shoulder-blade
+has a tendency to become horizontal, and we observe this change<span class="pagenum" id="Page_65">[65]</span> of
+movement in the model when the bone is seen along the posterior surface
+of the shoulder and the back, and we should scarcely recognise at first
+the appearances presented as those we are accustomed to study when it
+occupies its ordinary situation in the skeleton.</p>
+
+<p>But when the arm is elevated vertically, so that it comes in contact
+with the side of the head, movement takes place not only at the
+scapulo-humeral and at the acromio-clavicular joints, but also at
+the articulation of the internal extremity of the clavicle with the
+sternum. In that case, in fact, the whole of the shoulder is raised
+upwards (by the superior fibres of the trapezius muscle), and the
+clavicle represents the arm of the lever by which this movement
+is accomplished, while the sterno-clavicular articulation is the
+hinge. Thus we see the clavicle is changed in its direction, from
+the horizontal, to become oblique upwards and outwards—that is, its
+external extremity is raised and carried a little backwards.</p>
+
+<p>The clavicle plays a very important part in the movements of the
+upper limb. This explains why it is found specially developed
+in those animals whose fore-limbs possess the most specialised
+movements—flight, digging, burrowing, striking, or hugging—such as
+man, the monkey, the bat, the tiger, the mole, etc.; while in those
+quadrupedal animals which, like the horse, use their fore-limbs for
+progression only, and in which movements occur only in a plane parallel
+to that of the body, there is not a trace of clavicle. The part which
+the clavicle takes in the movements of the arm explains also why the
+bone presents a variable size in different<span class="pagenum" id="Page_66">[66]</span> individuals. It is stronger
+in the male than in the female; stronger in the working man than in
+the student; stronger, finally, on the right side than the left, from
+the habit of using the right arm for the most part in those actions
+which demand strength and skill. In the left-handed, it is the left
+clavicle that is stronger than the right. In a word, this bone is,
+like all the other parts of the skeleton, stronger in proportion as
+it takes part in active and frequently repeated movements. Thus the
+breadth of the shoulders is one of the characteristics of athletes; and
+it is to the strength of the bony structure formed by the clavicle and
+shoulder-blade, sustained by the first ribs, that the superior portion
+of the thorax owes its characteristic aspect.</p>
+
+<p>Owing to the presence of the shoulder girdle (scapula and clavicle)
+the thoracic cage does not present much of the form of a cone at its
+upper end, or summit; indeed, this region becomes broader in a lateral
+direction as the clavicle is more developed. It will be enough to
+contrast the region of the thorax in man with that of such animals as
+the dog or the horse, which, owing to the absence of a clavicle, have
+a thorax transversely flattened in the region of the shoulders, and
+consequently the shoulder-blades more closely applied upon the sides of
+the thoracic cage.</p>
+
+<p>This is the proper place to discuss the dimensions and proportions of
+the shoulder; but, as this study consists entirely of a comparison of
+the transverse diameters of the shoulders with the transverse diameters
+of the hips, it is better to defer it till after the description of the
+pelvis.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_67">[67]</span></p>
+
+<h2>CHAPTER VI.<br>
+<span class="subhed">THE HUMERUS AND ELBOW-JOINT.</span></h2></div>
+
+<div class="blockquot">
+
+<p class="hangingindent">The bony structure of the arm and elbow.—The shaft of the
+humerus.—The axis of the arm and forearm.—Spiral groove of the
+humerus; the inferior extremity of the humerus; the trochlea
+and capitellum; the external and internal supra-condyloid
+ridges.—The superior extremities of the two bones of the
+forearm; the ulna (sigmoid cavities, olecranon process, coronoid
+process); radius (head, neck).—The articulation of the elbow;
+transverse hinge joint.—Movements of flexion and extension;
+lateral movements.—The external form of the elbow; prominence
+of the internal condyle and olecranon process.</p>
+</div>
+
+
+<p>The <i>shaft of the humerus</i> is prismatic in its upper and middle
+parts, and flattened from front to back at its lower extremity.
+Covered over by thick muscles, its outward shape has for us but little
+interest; it is necessary only to note with regard to its direction
+that, when the arm is hanging down, the humerus is not altogether
+vertical, but is tilted slightly downwards and inwards. We shall see
+that the axis of the bones of the forearm is oblique in the opposite
+direction; for this reason the arm and forearm form at the elbow a very
+obtuse angle, looking outwards (Figs. <a href="#i_074">24</a>, <a href="#i_081a">26</a>).</p>
+
+<p>Among the details to be noted upon the shaft of the humerus, the
+<i>bicipital groove</i> is worthy of remark. This vertical groove,
+which separates the great from the small tuberosity on the front of
+the humerus at its upper end (Fig. <a href="#i_060">18</a>), is prolonged along the shaft
+of the bone, and presents an internal lip slightly prominent, and
+an external or anterior lip which is much more marked, which gives<span class="pagenum" id="Page_68">[68]</span>
+insertion to the broad tendon of the great pectoral muscle. At the
+line of junction of the superior with the middle third of the bone,
+this lip forms the anterior margin of a rough surface shaped like
+the letter <img src="images/thick_v.jpg" alt=""
+style="height:1em;  padding:0 0em 0 0em;">
+ (7, Fig. <a href="#i_060">18</a>), of which the angle
+looks downwards, and which, giving insertion to the deltoid muscle,
+has received the name of the <i>deltoid impression</i>. On the back of
+the humerus is another groove, broad and shallow, called the <i>spiral
+groove</i> of the humerus, which passes downwards and outwards along
+the shaft of the bone behind and below the deltoid impression.</p>
+
+<p>The inferior extremity of the humerus deserves to be studied in detail,
+as its shape gives the key to the movements of the elbow-joint, and
+explains at the same time several features of the region to be seen
+in the living model. This extremity is flattened from front to back,
+and is enlarged into a broad surface which is partly articular, partly
+non-articular. In the middle are two important articular prominences,
+smooth and covered with cartilage. Of these the internal portion is
+called the <i>trochlea</i> (<i>trochlea</i>, pulley). It possesses
+a groove and two unequal marginal ridges. The internal ridge is
+more prominent and descends lower than the external one. The other
+projection (11, Fig. <a href="#i_060">18</a>), which is situated on the outer side of the
+trochlea, is rounded in shape, and receives the name of the <i>radial
+head</i>, or <i>capitellum</i>. It is only obvious when the humerus is
+looked at from the front or from below: in other words, it does not
+appear (like the trochlear surface) on the posterior aspect of the
+lower end of the bone. This surface articulates<span class="pagenum" id="Page_69">[69]</span> with the upper end
+of the radius. There are three depressions, or fossæ, to be seen in
+relation to the articular surfaces of the lower end of the humerus. On
+the front of the bone, just above the trochlea and capitellum, are two,
+which receive the bones of the forearm during flexion of the limb: the
+<i>coronoid fossa</i> (for the coronoid process of the ulna), above the
+trochlear surface, and the <i>radial depression</i> for the head of the
+radius, much shallower, and placed above the capitellum. On the back,
+above the trochlear surface, is the <i>olecranon fossa</i>, into which
+the olecranon process is received during extension of the forearm.</p>
+
+<p>The lateral portions of the inferior extremity of the humerus are
+formed by rough, non-articular projections which give attachment to
+muscles and ligaments, and are known respectively as the <i>external
+condyle</i> and the <i>internal condyle</i> of the humerus (14, 14,
+Fig. <a href="#i_060">18</a>). Above each condyle is a well-marked bony ridge, which is
+called the <i>supra-condyloid ridge</i> (external or internal) (13, 13,
+Fig. <a href="#i_060">18</a>).</p>
+
+<p>The lower end of the humerus articulates with the upper extremities
+of the bones of the forearm; and we will next proceed to study the
+formation of these extremities in order to understand the movements of
+the elbow-joint and the form of the region.</p>
+
+<p>The forearm is formed of two bones (Fig. <a href="#i_070">21</a>), which, when the upper
+limb is hanging beside the body, the palmar surface of the hand being
+turned forwards, are placed parallel to each other—one on the outer,
+one on the inner side. The inner bone (1, Fig. <a href="#i_070">21</a>) is called the
+<i>ulna</i>, or <i>cubitus</i>,<span class="pagenum" id="Page_70">[70]</span> and it is that which by its upper
+extremity (<i>olecranon</i>) forms the bony prominence of the elbow;
+the outer bone (10, Fig. <a href="#i_070">21</a>) is called the <i>radius</i> (from the
+Latin <i>radius</i>, a spoke of a wheel), and it is by this bone
+chiefly that the bones of the wrist and hand are carried. For the
+present we will describe only the upper extremities of these two bones
+(Figs. <a href="#i_070">21</a> and <a href="#i_071">22</a>).</p>
+
+  <div class="figcenter" id="i_070" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_070.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 21.</p>
+     <p class="p0 sm"><span class="smcap">The Bones of the Forearm</span> (anterior surface): 1, shaft
+of ulna;—2, great sigmoid cavity;—3, lesser sigmoid cavity
+with head of radius;—4, olecranon;—5, coronoid process;—7,
+interosseous space;—8, inferior extremity of ulna with
+styloid process (9);—10, shaft of radius;—11, its head;—12,
+neck;—13, tubercle for biceps;—14, impression for pronator
+teres muscle;—15, inferior extremity of radius with styloid
+process (16).</p>
+  </div>
+
+<p>The superior extremity of the ulna presents two processes and
+two articular cavities. The cavities are the <i>greater</i> and
+<i>lesser</i> sigmoid cavities; the processes are the coronoid and
+olecranon processes. The bone articulates with the pulley or trochlea
+of the humerus by means of the <i>great sigmoid cavity</i>, and
+with the margin of the head of the radius by the <i>lesser sigmoid
+cavity</i>. The greater sigmoid cavity (2, Fig. <a href="#i_070">21</a>) presents in its
+centre a ridge prominent from before backwards, which corresponds to
+the groove in the trochlea of the humerus. Below and in front, the
+great sigmoid cavity is formed (5, Fig. <a href="#i_070">21</a>) by a bony prominence called
+the <i>coronoid process</i> (compared to the beak of a crow: κορώνη,
+a crow; εἶδος, form), which is lodged in the coronoid fossa of<span class="pagenum" id="Page_71">[71]</span> the
+humerus in flexion of the forearm (17, Fig. <a href="#i_060">18</a>). Above and behind,
+the great sigmoid cavity is formed by the <i>olecranon process</i>
+(ὠλενη, the elbow; κάρηνον, the head), a large square projection (4,
+Fig. <a href="#i_070">21</a>), which constitutes the prominent point of the elbow, and which
+accentuates in a high degree the form of the forearm during flexion.
+During extension of the forearm the olecranon process is lodged partly
+in the <i>olecranon fossa</i> of the humerus (4, Fig. <a href="#i_073">23</a>). The lesser
+sigmoid cavity of the ulna is a small concave surface placed on the
+outer side of the coronoid process for articulation with the margin of
+the head of the radius.</p>
+
+  <div class="figcenter" id="i_071" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_071.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 22.</p>
+     <p class="p0 sm"><span class="smcap">Figure of the Elbow Joint, right side</span> (anterior
+view):—1, inferior portion of shaft of humerus;—2, ulna;—3,
+radius;—4, external condyle;—5, internal condyle;—6,
+capitellum;—7 and 8, trochlea;—9, coronoid fossa;—10,
+coronoid process;—11, head of radius.</p>
+  </div>
+
+<p>The superior extremity of the radius forms a small discoidal head
+(11, Fig. <a href="#i_070">21</a>) attached by a narrow neck to the body of the bone; this
+head is flattened at the top and hollowed out to articulate with the
+<i>capitellum</i> of the humerus (Fig. <a href="#i_071">22</a>). The margin of the head of
+the radius revolves in the lesser sigmoid cavity of the ulna.</p>
+
+<p>We see, then, that the articular surfaces of the elbow are formed on
+the humerus (6, 7, 8, Fig. <a href="#i_071">22</a>) by a transverse series of projections
+(the trochlea and capitellum), and on the bones of the forearm by a
+series of depressions moulded on these projections, so that the whole
+describes a movement<span class="pagenum" id="Page_72">[72]</span> similar to that between two cog-wheels (Fig.
+<a href="#i_071">22</a>), a species of transverse hinge. Thus it is easy to understand,
+<i>à priori</i>, how this disposition of the parts does not permit of
+any lateral displacement of the bones, or transverse movement; the
+movements forward and backward are, in fact, the only kind possible
+in the elbow-joint. The forward movement—that is to say, that by
+which the anterior surface of the forearm is brought near the anterior
+surface of the arm—constitutes <i>flexion</i> of the forearm. The
+movement in the opposite direction constitutes <i>extension</i>.</p>
+
+<p>The disposition of the ligaments—that is, of the fibrous bands or
+articular capsule which fasten the bones together—modifies very
+slightly the mechanism we have just deduced from the shape of the
+articular surfaces; in fact, this capsule is formed on the inner and
+outer surfaces by ligamentous fibres, very dense and short, called the
+lateral ligaments, which prevent all lateral movement. On the other
+hand, the anterior and posterior portions of the capsule are loose,
+so as not to offer any opposition to the movements of flexion and
+extension. The only limit to these movements is that resulting from
+the bony projections of the ulna coming in contact with the humerus.
+Thus, the movement of flexion can be prolonged until the coronoid
+process arrives at the coronoid fossa and touches the bottom of that
+cavity; then the fleshy masses of the forearm come into contact with
+the anterior surface of the arm, especially if the model is muscular,
+and flexion is no longer possible. The movement of extension, on the
+contrary, has a limit which it is important to<span class="pagenum" id="Page_73">[73]</span> state precisely,
+resulting from the beak of the olecranon touching the bottom of the
+olecranon fossa (Fig. <a href="#i_073">23</a>); this is produced when the forearm has
+attained, in the movement of extension, that situation which brings its
+own axis into direct line with that of the arm. The extension of the
+elbow cannot therefore exceed the degree which brings the humerus and
+forearm into the same plane; that is to say, the forearm can never make
+with the arm an angle facing backwards.</p>
+
+  <div class="figcenter" id="i_073" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_073.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 23.</p>
+     <p class="p0 sm"><span class="smcap">Antero-posterior section of the Elbow</span> (through the
+ulna):—1, humerus;—2, ulna;—3, coronoid fossa;—4, olecranoid
+fossa;—5, olecranon;—6, coronoid process;—7, section of
+trochlea.</p>
+  </div>
+
+<p>By comparing the particulars of the mechanism of the elbow with that
+which we have previously seen of the mechanism of the scapulo-humeral
+articulation, it will be easy to understand how we may, from the
+study of the articular surfaces and ligaments, learn the laws of the
+mechanism of joints. For example, the head of the humerus received into
+a single concavity may allow to the arm every kind of movement; in the
+same way the arrangement of a hinge-joint, with a series of projections
+and depressions, fitted one to the other in a transverse line, renders
+possible in the elbow-joint only the movements of flexion and extension.</p>
+
+<p>In regard to external form, we learn the following facts from a
+knowledge of the bones which form the elbow-joint.</p>
+
+<p>1. With respect to the angle which the forearm<span class="pagenum" id="Page_74">[74]</span> makes with the arm, if
+we examine it either upon the skeleton or upon the living subject, the
+upper limb hanging beside the body, with the palm of the hand turned
+forward, it is seen that the humerus (page 67) is slightly oblique
+from above downwards and inwards, while the two bones of the forearm
+are directed obliquely in the opposite direction—that is, from above
+downwards and outwards. In other words, the bones of the arm and
+forearm form at their point of junction—that is, at the level of the
+elbow—an <i>angle</i> the base of which looks outwards and the apex
+inwards. This angle only appears in extension of the limb, and is due
+to the twisted and tilted form of the trochlear surface of the humerus.</p>
+
+  <div class="figcenter" id="i_074" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_074.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 24.</p>
+     <p class="p0 sm center"><span class="smcap">Outline of Upper Limb</span> (front view)</p>
+  </div>
+
+<p>2. Concerning the bony prominences which are seen beneath the skin
+at the elbow (Fig. <a href="#i_074">24</a>), after studying these osseous structures, we
+should be able to<span class="pagenum" id="Page_75">[75]</span> recognise upon the living model those details of
+the figure which correspond to the four bony points—namely, the
+coronoid process in front, the olecranon behind, the external condyle
+on the outer side, and the internal condyle on the inner side. The
+coronoid process, covered by muscles, is so buried in the surrounding
+structure that it does not show externally. It is much the same also
+with the external condyle, as this projection, not very prominent
+in the skeleton, disappears completely in the living subject, since
+this external condyle is situated at the bottom of the angle facing
+outwards which the forearm makes with the arm, and the mouth of this
+angle is filled up by the external muscles of the forearm (especially
+the brachio-radialis, or supinator longus), which take their origin
+from the external border of the humerus. The external condyle and the
+external supra-condyloid ridge can be felt beneath the skin; and the
+former occupies a depression at the back of the elbow on its outer side
+in extension of the forearm.</p>
+
+<p>On the other hand, the internal condyle, supra-condyloid ridge, and
+the olecranon process always show clearly beneath the skin, and the
+olecranon forms that projection, commonly called the <i>point of the
+elbow</i>, which is so prominent behind during flexion of the forearm,
+and which follows the movements of the forearm, seeming to rise
+towards the arm during the extension of the forearm, and to descend
+during flexion. The internal condyle projects as the apex of the angle
+formed by the axis of the forearm with that of the arm (Fig. <a href="#i_081a">26</a>, page
+81); this is a fixed point placed a little above<span class="pagenum" id="Page_76">[76]</span> the line of the
+elbow-joint, which is useful in measurements.</p>
+
+<p>There is one detail which we must not forget at this stage; in
+comparing the length of the forearm with that of the arm the olecranon
+must be excluded, as it projects above the lower end of the humerus; on
+the other hand, the internal condyle should rather be chosen as a fixed
+point from which measurements may be taken.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_77">[77]</span></p>
+
+<h2>CHAPTER VII.<br>
+<span class="subhed">SKELETON OF THE FOREARM: PRONATION AND SUPINATION.</span></h2></div>
+
+<div class="blockquot">
+
+<p class="hangingindent">The bones of the forearm; ulna and radius.—The lower
+extremities of these bones; their styloid processes;
+triangular fibro-cartilage of the wrist.—<i>Pronation</i> and
+<i>supination</i>: change of form and direction of the forearm:
+and position of the hand.—Prominences of the wrist (styloid
+processes); the angle which the axis of the hand makes with that
+of the forearm.</p>
+</div>
+
+
+<p>We have already examined the upper ends of the bones of the forearm
+(radius and ulna) in relation to the elbow-joint. We have still to
+examine their shafts and lower extremities; and in this chapter we will
+continue their description, and study the movements of the two bones,
+and the relation which they bear to the wrist-joint and the hand. In a
+state of rest the two bones lie parallel, the radius externally, and
+the ulna internally, separated except at their extremities by a wide
+interosseous space.</p>
+
+<p>A superficial glance at the bony structure of the forearm (Fig. <a href="#i_070">21</a>,
+p. 70) suffices to show that the two bones which compose it offer in
+many respects a striking contrast to each other. They differ first
+of all in the relative position which they hold in the forearm. The
+inner bone is the ulna, which extends upwards beyond the radius by
+reason of the length of the olecranon process. On the other hand, in
+the neighbourhood of the wrist, the radius extends beyond the ulna
+and descends below it. We should also note at the outset that the
+radius, descending below the ulna, is found to be the only bone of
+the<span class="pagenum" id="Page_78">[78]</span> forearm which articulates directly with the hand and forms the
+wrist-joint, or <i>radio-carpal</i> articulation. The lower end of the
+ulna is separated by a wide space from the carpus (<i>cuneiform</i>
+bone), which is filled up in the living subject by the <i>triangular
+fibro-cartilage</i> of the wrist-joint. As regards size also these
+bones present a contrast; the ulna is thick and bulky in its upper
+part, but becomes thinner as it descends, and its inferior extremity is
+slender (Fig. <a href="#i_070">21</a>); the radius, on the other hand, is relatively small
+at its upper end, and increases in size below, so that its inferior
+extremity, articulating with the hand, forms a large bony surface.</p>
+
+<p>We need not enter into minute details regarding the shape of the shafts
+of the two bones.</p>
+
+<p>They are regularly prismatic in form. At the upper end of the shaft of
+the radius, immediately below the neck, is a tuberosity (13, Fig. <a href="#i_070">21</a>),
+directed forwards and inwards, which gives insertion to the tendon of
+the biceps (<i>bicipital tubercle</i>). From this tuberosity an oblique
+line passes downwards and outwards, and terminates upon the middle part
+of the external surface of the bone in a rough space (14, Fig. <a href="#i_070">21</a>)
+called the <i>impression for the pronator radii teres</i>, because it
+gives insertion to the muscle of that name.</p>
+
+<p>With regard to the shaft of the ulna, we need only notice that its
+posterior border is subcutaneous in its whole extent, and can be felt
+beneath the skin from the elbow to the wrist.</p>
+
+<p>The lower end of the radius is enlarged and massive. On its inner side
+it articulates with the ulna. Externally it is prolonged downwards as
+the<span class="pagenum" id="Page_79">[79]</span> <i>styloid process</i>, which forms a well-marked prominence at
+the outer side of the wrist. The inferior surface is hollowed into a
+smooth triangular surface for articulation with two of the bones of the
+wrist (<i>scaphoid</i> and <i>semi-lunar</i>).</p>
+
+<p>The inferior extremity of the ulna is much smaller. It presents a
+rounded head (8, Fig. <a href="#i_070">21</a>), which articulates externally with the
+radius, and below with the <i>triangular fibro-cartilage of the
+wrist</i>, which intervenes between the ulna and the carpus, and
+fills the gap between that bone and the cuneiform bone. The ulna is
+prolonged on its inner side and behind into a <i>styloid process</i>
+which forms the internal prominence of the wrist. We have already said
+that the inferior extremity of the ulna does not descend as low as the
+corresponding portion of the radius; the triangular fibro-cartilage,
+which lies below the ulna, proceeds from the external border of the
+inferior extremity of the radius to the base of the styloid process of
+the ulna; the bones of the wrist articulate with the radius and with
+this triangular fibro-cartilage, so that the ulna does not take part
+directly in the articulation of the forearm with the hand (Fig. <a href="#i_088">28</a>,
+page 88). The relation of the ulna to the wrist-bones is well shown in
+a radiograph of the hand, in which the space between the bones at the
+inner side of the wrist is clearly seen (Fig. <a href="#i_080">25</a>). This arrangement is
+of prime importance, as will be seen later, in the movements of the
+wrist. On account of this space between the ulna and the carpus, the
+movement of <i>adduction</i> (drawing inwards of the hand) is much
+freer and more extensive than <i>abduction</i>.</p>
+
+<p><span class="pagenum" id="Page_80">[80]</span></p>
+
+  <div class="figcenter" id="i_080" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_080.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 25.</p>
+     <p class="p0 sm"><span class="smcap">The Hand and Wrist</span>: From a radiograph taken specially for this
+work by Dr. Thurstan Holland, Liverpool.</p>
+  </div>
+
+  <div class="figcenter" id="i_081a" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_081a.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 26.</p>
+     <p class="p0 sm"><span class="smcap">Right Forearm in Supination</span> (the radius and radial half
+of the hand are shaded by oblique lines): the radius is parallel
+to the ulna.</p>
+  </div>
+
+  <div class="figcenter" id="i_081b" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_081b.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 27.</p>
+     <p class="p0 sm"><span class="smcap">The Right Forearm in Pronation</span>: the radius (shaded)
+crosses the ulna, and the radial half of hand (shaded) is placed
+on the inner side.</p>
+  </div>
+
+<p>Up to the present we have considered the two bones of the arm as placed
+parallel side by side, and separated by a comparatively broad interval,
+called the <i>interosseous space</i> (7, Fig. <a href="#i_070">21</a>). In fact, they are so
+placed, when the arm is hanging beside the body, in a state of rest,
+with the palm of the hand directed forwards (Fig. <a href="#i_081a">26</a>), or placed on a
+flat surface, palm upwards; the hand is then lying on its back, and
+this position we call <i>supination</i> (<i>supinus</i>, lying on the
+back). But the hand may be changed in position,<span class="pagenum" id="Page_81">[81]</span> turned round so that
+its posterior surface is directed forward (Fig. <a href="#i_081b">27</a>), or, if the forearm
+be placed on a flat surface, the back of the hand is turned upwards. In
+this new position, when the hand lies on its<span class="pagenum" id="Page_82">[82]</span> palmar aspect, we speak
+of it as being in the position of <i>pronation</i> (<i>pronus</i>,
+lying on the belly).</p>
+
+<p>This change from supination to pronation is accomplished by a change
+in the relations of the bones of the forearm to one another. They
+cease to be parallel when the hand is prone, and cross each other;
+but the two bones do not move similarly in this action; one of them,
+the ulna, practically remains fixed; the other, the radius, changes
+its position so as to cross it. On examining the points of contact
+between the radius and ulna—namely, the superior and inferior
+articulations of these two bones—we see that the <i>superior
+radio-ulnar articulation</i> is formed by the circumference of the
+head of the radius received within the cavity (<i>lesser sigmoid
+cavity</i>), situated on the outer surface of the coronoid process of
+the ulna; whilst the <i>inferior radio-ulnar articulation</i> is formed
+by a sigmoid cavity situated on the internal surface of the inferior
+extremity of the radius, which articulates with the circumference of
+the head of the ulna.</p>
+
+<p>The axis of movement may be represented by a line drawn through the
+centres of the upper end of the radius and the lower end of the ulna.
+In the superior radio-ulnar articulation, the head of the radius
+revolves on its own axis and turns in the sigmoid cavity of the ulna;
+the superior extremity of the radius itself does not change its
+position; in the inferior radio-ulnar articulation, on the contrary,
+the radius moves round the head of the ulna, as a wheel round its axle.</p>
+
+<p>These considerations of articular mechanism may be best understood
+by examining a portion<span class="pagenum" id="Page_83">[83]</span> of the skeleton containing the bones of the
+forearm, which, as is usual in articulated preparations, are connected
+together by metallic bands that permit the normal movements. In
+causing the hand to pass from supination to pronation, we see that
+it is necessary to bring the shaft of the radius across that of the
+ulna in such a manner that while the upper end of the radius still
+remains on the outer side, its lower end is entirely altered in
+position, and is carried to the inner side of the ulna (Figs. <a href="#i_081a">26</a> and
+<a href="#i_081b">27</a>). In accomplishing this movement, we perceive that the hand, which
+articulates only with the radius, must follow the movement of this
+bone, so that the thumb or radial border of the hand must change from
+the outer to the inner side; the palm of the hand, which in supination
+is directed forwards, is turned backwards in pronation, and it is this
+movement of the radius on the ulna which constitutes the passage from
+supination (Fig. <a href="#i_081a">26</a>) to pronation (Fig. <a href="#i_081b">27</a>).</p>
+
+<p>The general form of the forearm, irrespective of the details which
+we shall explain later, regarding the configuration of the muscles,
+depends directly on the position of these bones, and is changed
+according as they are parallel or crossed. When the hand is supinated
+(Fig. <a href="#i_081a">26</a>), the radius being then placed parallel to the ulna and
+separated from it by a large interosseous space, the form of the
+forearm is that of the segment of a limb presenting two borders—an
+external, or radial, and an internal, or ulnar—and two surfaces, one
+anterior, the other posterior. The forearm, in a word, is slightly
+flattened from front to back, because the<span class="pagenum" id="Page_84">[84]</span> bones are parallel to each
+other. But when, from the position of supination, the hand passes to
+that of pronation, the two bones cross each other and come in contact,
+and the interosseous space practically disappears (Fig. <a href="#i_081b">27</a>). The radius
+and ulna, taken together, form a single mass, which may be compared
+to that which two rods assume, placed at first parallel at a certain
+distance from each other, and which afterwards cross and come into
+direct contact. Thus in pronation the shape of the forearm becomes
+completely changed, especially in its lower two-thirds. Instead of a
+segment of a limb with two surfaces and two borders, it represents a
+segment rounded and almost cylindrical in its middle part; in complete
+supination, only the inferior part (wrist) and the superior part (bend
+of the elbow) preserve the form flattened from front to back.</p>
+
+<p>Artists are usually not sufficiently imbued with these important facts;
+they are inclined to believe that if a figure has been represented with
+the forearm in a position of supination, and that for some reason this
+attitude has been changed to that of pronation, it is enough to change
+the hand and wrist alone, without altering the model of the forearm in
+any other detail. On the other hand, the form of the forearm throughout
+its entire extent and particularly in the middle part, undergoes a
+change when the hand passes from supination to pronation, and the
+reverse; and this fact will be still more evident when, in studying
+the muscles of the region, we see that their direction is completely
+altered, and this also helps to modify the shape of the limb.</p>
+
+<p><span class="pagenum" id="Page_85">[85]</span></p>
+
+<p>In the movements of pronation and supination, the forearm changes
+not only in form, but also in direction. We have previously seen
+that when the radius and ulna are placed parallel one with the other
+(supination), the axis of the forearm makes with that of the arm an
+angle opening outwards. We may again express this fact by saying that
+if in this case we prolong the axis of the humerus downwards (see the
+dotted line in Fig. <a href="#i_081a">26</a>), this axis falls internal to the head (inferior
+extremity) of the ulna, and consequently lies well to the inner side of
+the radius and interosseous space. But in pronation, the result is that
+when the radius crosses the ulna at its centre, and is placed internal
+to it at its lower end, the two crossed bones of the forearm, taken
+together, make a continuous line with the humerus, the angle at the
+inner side of the elbow disappears, and the axis of the arm and that of
+the forearm are almost in the same straight line (Fig. <a href="#i_081b">27</a>).</p>
+
+<p>In order to make the best use of the various details of the bony
+structures which we have been studying in their application to outward
+form we will, before commencing the study of the hand, mark once more
+the prominences which occur at the lower ends of the radius and ulna at
+the level of the wrist. Of these two projections, which are to the hand
+what the ankle-bones, or malleoli, are to the feet, one is external,
+formed by the styloid process of the radius (16, Fig. <a href="#i_070">21</a>), the other is
+internal, and is formed by the head of the ulna and its styloid process
+(9, Fig. <a href="#i_070">21</a>).</p>
+
+<p>The styloid process of the radius is situated<span class="pagenum" id="Page_86">[86]</span> much lower than the
+styloid process of the ulna.</p>
+
+<p>This position of the bones we may easily verify upon ourselves, without
+a skeleton, by clasping with the thumb and index-finger of one hand
+the wrist of the other; we then perceive that the radius descends much
+lower than the ulna (Fig. <a href="#i_070">21</a>). Hence the articular line of the forearm
+with the hand is obliquely directed from above downwards and outwards
+(the hand being supinated). So that the hand is articulated with the
+forearm at an angle, due to the downward prolongation of the lower
+end of the radius: a position which, along with the presence of the
+articular fibro-cartilage of the wrist, is responsible for the more
+extensive capacity for adduction than abduction of the hand at the
+wrist-joint.</p>
+
+<p>In the extended and supine position of the limb the junction of the arm
+and the forearm forms an angle opening outwards; that of the forearm
+and hand forms an angle opening inwards.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_87">[87]</span></p>
+
+<h2>CHAPTER VIII.<br>
+<span class="subhed">THE HAND.—PROPORTIONS OF THE UPPER LIMB</span></h2></div>
+
+<div class="blockquot">
+
+<p class="hangingindent">The bony structure of the hand.—The wrist, or carpus; eight
+bones in two rows, superior and inferior.—The radio-carpal
+articulation, or wrist-joint.—Carpal joints.—The form of the
+wrist during flexion.—The palm of the hand, or metacarpus;
+metacarpal bones; their relative lengths (form of the
+fist).—Carpo-metacarpal articulations; the articulation of
+the thumb.—The fingers, or phalanges.—Articulations of the
+phalanges; their movements.—Proportions of the upper limb: the
+arms extended (the square figure of the ancients); the hand as
+a common measure; the middle finger and the Egyptian Canon of
+Charles Blanc.—Brachial index.</p>
+</div>
+
+
+<p>The hand is composed of three parts: the wrist, the palm, and
+the fingers. The bony structure of the wrist is formed by the
+<i>carpus</i>, that of the palm by the <i>metacarpus</i> (μετὰ, below;
+καρπὸς, the wrist); the fingers are formed by small bones called
+<i>phalanges</i> (Fig. <a href="#i_080">25</a>, page 80).</p>
+
+<p>As the carpus is almost completely hidden by soft parts, fibrous and
+tendinous, we shall first proceed to enumerate the bones which compose
+it, and show their articulations.</p>
+
+<p>Notwithstanding its small compass, the carpus is made up of not
+less than eight bones, which are placed in two transverse rows, one
+<i>superior</i>, or <i>brachial</i> (next the forearm), the other
+<i>inferior</i>, or <i>metacarpal</i> (next the metacarpus).</p>
+
+<p>The bones of the two rows are arranged as follows, enumerating them
+in order from without inwards—that is, from the radial to the ulnar
+border of the wrist:—The four bones of the first row are:<span class="pagenum" id="Page_88">[88]</span> the
+<i>scaphoid</i> (S, Fig. <a href="#i_088">28</a>), named from the cavity on the inferior
+surface being compared to a boat (<i>σκάφη</i>, a boat; <i>εἶδος</i>,
+form); the <i>semi-lunar</i> (L, Fig. <a href="#i_088">28</a>); the <i>cuneiform</i> (C,
+Fig. <a href="#i_088">28</a>) (whose names indicate their shape); and the <i>pisiform</i>
+(P, Fig. <a href="#i_088">28</a>), which, small and rounded, is placed on the anterior
+surface of the cuneiform bone, and articulates with it alone (Fig.
+<a href="#i_090">29</a>). The four bones of the second row, still naming them from without
+inwards, are (Fig. <a href="#i_088">28</a>): <i>trapezium</i>, <i>trapezoid</i>, <i>os
+magnum</i>, and <i>unciform</i> bones (<i>uncus</i>, a hook).</p>
+
+  <div class="figcenter" id="i_088" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_088.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 28.</p>
+     <p class="p0 sm"><span class="smcap">The Bony Structure of the Wrist</span> (dorsal surface):
+<span class="allsmcap">R</span>, radius;—<span class="allsmcap">U</span>, ulna;—<span class="allsmcap">F</span>, triangular
+fibro-cartilage;—<span class="allsmcap">S</span>, scaphoid;—<span class="allsmcap">L</span>,
+semi-lunar;—<span class="allsmcap">C</span>, cuneiform;—<span class="allsmcap">P</span>,
+pisiform;—<span class="allsmcap">T</span>, trapezium;—<span class="allsmcap">T</span>,
+trapezoid;—<span class="allsmcap">M</span>, os magnum;—<span class="allsmcap">U</span>, unciform.—Below
+the carpus: 1, 2, 3, 4, 5, the five metacarpal bones counting
+from that of thumb (1).</p>
+  </div>
+
+<p>An examination of the bony structure of the carpus as a whole shows
+that the anterior or palmar surface presents the form of a vertical
+groove, limited on the inner side by the forward projections of the
+pisiform and unciform bones, and on the outer side by the projections
+of the scaphoid and trapezium. This groove is formed into a canal by
+means of a broad fibrous band (the <i>anterior annular ligament</i> of
+the wrist), which passes like a bridge across the wrist between the
+prominences just named. Beneath this bridge, and in the canal thus
+formed, pass the tendons of the flexor muscles of the fingers, the
+fleshy bellies of which occupy the forearm, while their<span class="pagenum" id="Page_89">[89]</span> tendinous
+insertions are attached to the phalanges. This explains the fact that
+these tendons, seen at the lower part of the forearm, are not visible
+superficially during their passage into the palm of the hand.</p>
+
+<p><i>The Wrist-Joint.</i>—The <i>radio-carpal</i> joint is formed by
+the convex upper surface of the carpus, constituted by the scaphoid,
+semi-lunar, and cuneiform bones, articulating with the lower end of
+the radius and the fibro-cartilage of the wrist (which lies below
+the ulna). This articulation permits movements of the hand in four
+directions: forwards and backwards (flexion and extension); outwards
+and inwards (abduction and adduction).</p>
+
+<p><i>Inter-carpal Joint.</i>—The several carpal bones glide upon one
+another: and there is only a limited movement possible of flexion and
+extension between the three named bones of the first row (scaphoid,
+semi-lunar, and cuneiform) and the four bones of the second row; but
+lateral movements are very limited and practically absent.</p>
+
+<p>It is thus obvious that the movements of flexion and extension of the
+hand at the wrist-joint are extensive, and amount almost to a right
+angle, both before and behind, the mobility of the radio-carpal and
+inter-carpal articulations aiding each other in these movements; on
+the contrary, the lateral movements of the wrist are more limited, as
+they are confined to the radio-carpal articulation, and are restricted
+on the outer side (abduction) by the downward projection of the lower
+end of the radius. Adduction is a much more powerful movement, rendered
+freer by the presence of the triangular<span class="pagenum" id="Page_90">[90]</span> fibro-cartilage of the wrist,
+and the separation of the ulna and the cuneiform bones. It should also
+be noted that in flexion of the hand, when it forms a right angle with
+the forearm, the posterior surface of the wrist does not present an
+abrupt curve, but rather a rounded form; the convexity being made up
+of two series of articulations, the radio-carpal and the inter-carpal
+articulations.</p>
+
+  <div class="figcenter" id="i_090" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_090.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 29.</p>
+     <p class="p0 sm"><span class="smcap">Bony Structure of Hand</span> (anterior or palm surface).—1,
+2, 3, and 4, the four bones of superior row of carpus:—5, 7,
+8, and 9, the four bones of inferior row;—10, 10, the five
+metacarpal bones;—11, 11, the first phalanges;—12, 12, the
+second phalanges;—13, 13, the third phalanges;—14 and 15, the
+two phalanges of the thumb.</p>
+  </div>
+
+<p>The <i>metacarpus</i> (Fig. <a href="#i_090">29</a>), or skeleton of the palm of the
+hand, is composed of five slender, long bones—the five metacarpal
+bones—separated from each other by <i>interosseous</i> spaces. Each
+metacarpal bone, like the other long bones, is composed of a shaft and
+two extremities. The shaft is more or less prismatic and triangular;
+the upper or carpal extremity is cuboid, or wedge-shaped; the lower or
+digital end is rounded to articulate with the first bone of the finger.
+The five bones are distinguished by the names, first, second, third,
+fourth, and fifth metacarpal, counting from the thumb to the little
+finger; or, again, by the name of the finger to which they correspond
+(as the metacarpal bone of the thumb, index finger, etc.).<span class="pagenum" id="Page_91">[91]</span> The
+first metacarpal bone, or that of the thumb, is the shortest, and is
+remarkable for characteristics to which reference will be made later;
+the second, or metacarpal bone of the index finger, and the third, or
+that of the middle finger, are the longest. The third is generally
+longer than the second, so that a line passing through the heads of
+the series of metacarpal bones describes a curve with its convexity
+downwards, of which the most prominent part corresponds to the head
+of the third metacarpal bone. When the hand is firmly closed, and the
+fingers bent in the palm, it is the head of the third metacarpal bone
+which forms the most prominent part of the fist.</p>
+
+<p>The metacarpal bones articulate with the carpus by their upper
+extremities, or bases. In these articulations a very different
+arrangement is found for the first metacarpal bone when compared with
+that of the other four.</p>
+
+<p>The articulation of the metacarpal bone of the thumb is formed by a
+saddle-shaped facet on the trapezium, concave from side to side, and
+convex from before backwards, and a corresponding facet at the base
+of the first metacarpal bone. It results, then, that as the rider
+can move himself on his saddle forwards and backwards, and to either
+side, so the metacarpal bone of the thumb is equally movable in all
+directions, and can accomplish the movement of circumduction, by
+which the extremity of the thumb describes a circle. This mobility
+permits the thumb to be separated from the other fingers, or to be
+drawn across the hand, or to touch the tips of the other fingers.<span class="pagenum" id="Page_92">[92]</span>
+This last is called the <i>movement of opposition</i> of the thumb,
+and it is owing to this property that the thumb possesses of opposing
+itself to the fingers that the hand of man forms such a wonderful
+organ for prehension and for performing the most delicate and refined
+movements. The articulation of the trapezium and metacarpal bone, which
+is the source of these movements, thus deserves particular mention.
+The articular surfaces of the two bones are attached to each other by
+an articular capsule sufficiently loose to allow all the movements of
+which the first metacarpal bone is capable.</p>
+
+<p>On the other hand, the articulations of the metacarpal bones of the
+four other fingers do not present any such mobility. In fact, whilst
+the base of the first metacarpal bone is free, without being connected
+with that of the second, the bases of the other metacarpal bones are
+in contact with each other by their lateral surfaces, and are united
+by dorsal, palmar, and interosseous ligaments. Again, the transverse
+line of union between the second row of the carpus and the base of
+these metacarpal bones (carpo-metacarpal line) is irregular, the carpus
+and metacarpus being dovetailed into each other, especially at the
+level of the second and third metacarpals, by reason of the projection
+upwards of the second metacarpal bone, and the projection downwards of
+the os magnum (Fig. <a href="#i_090">29</a>). The carpus and the four last metacarpal bones
+therefore form a series of joints, of which the parts are only slightly
+movable one on the other, giving a certain elasticity to the whole.
+The<span class="pagenum" id="Page_93">[93]</span> effects of pressure or sudden shock are avoided by the presence of
+numerous parts united in such a manner as to glide one on the other, at
+the same time not presenting any independent mobility.</p>
+
+<p>The fingers are formed of a series of slender bones placed end to end,
+and termed <i>phalanges</i>. Each finger has three phalanges, except
+the thumb, which has only two. We distinguish the rows of phalanges by
+the names of the first, second, or third, counting from the base to the
+free extremity of the fingers; and we give the name of <i>ungual</i>
+phalanx to the last because it supports the nail. These phalanges,
+like the other long bones, are made up of a shaft and two extremities.
+The shaft is semi-cylindrical in shape, rounded behind and flattened
+in front, where the flexor tendons of the fingers are lodged. The
+extremities present characters which will be pointed out when the
+articulations of the fingers are studied.</p>
+
+<p>The articulations of each finger are: the metacarpo-phalangeal
+articulation, the articulation of the first with the second, and the
+articulation of the second with the third phalanges (inter-phalangeal
+articulations).</p>
+
+<p>Each <i>metacarpo-phalangeal articulation</i> is formed by the globular
+head of the metacarpal bone being received into a glenoid cavity in the
+base of the first phalanx. Such an adaptation of articular surfaces
+will permit every kind of movement, and it is easy to understand
+that each finger can be bent on the metacarpus, straightened, and
+also inclined to either side (abduction and adduction—the act of
+separating and bringing together the fingers); but<span class="pagenum" id="Page_94">[94]</span> the articular
+capsule or fibrous band which surrounds each metacarpo-phalangeal
+joint fixes an exact limit to these movements. Flexion is a much
+more powerful movement than extension, because the capsules of the
+joints are deficient behind, their places being taken by a membranous
+expansion of the extensor tendons which passes over the backs of the
+joints. Thus extension cannot usually be prolonged further than that
+position in which the axis of the fingers forms a straight line with
+that of the metacarpal bones, for just then the anterior portion of the
+capsule is put on the stretch, and as this part is fibrous, thick, and
+resisting, it prevents any increase of extension. When the anterior
+ligament is thinner and more relaxed, as sometimes in the female hand,
+the fingers can be straightened beyond the straight line, and form
+an obtuse angle with the metacarpus. On the other hand, this capsule
+is strengthened on either side by a lateral ligament, which, being
+inserted at the posterior part of the head of the metacarpal bone, is
+put on the stretch when the act of flexion is produced, and when this
+act of flexion arrives at a right angle, the lateral ligaments do not
+permit it to be carried any farther. It is easy to prove this upon
+ourselves, as we cannot flex the first phalanx on the metacarpus beyond
+this point, and we cannot, in any case, bring the anterior surface of
+the first phalanx of a finger in contact with the palm of the hand, but
+only the second and third phalanges.</p>
+
+<p><i>Inter-phalangeal Articulations.</i>—The articulations of the
+phalanges—that is, those of the first with the second, and those of
+the second with the third—are constructed on a different plan from
+the<span class="pagenum" id="Page_95">[95]</span> metacarpo-phalangeal articulations. Instead of a head received
+into a glenoid cavity, we find here, at the inferior extremity of
+the first and second phalanges, a surface formed like a pulley, or
+trochlea, with two lateral lips separated by a groove or hollow
+(Fig. <a href="#i_090">29</a>); and, on the other hand, on the superior extremity of the
+second and third we find two cavities corresponding to the lips of
+the pulley, separated by a median projection which corresponds to the
+groove. Therefore, given a single phalanx, it will be easy to say
+whether it is a first, second, or third phalanx, as the first phalanx
+has at its upper end a single articular cavity, while the second and
+third have two placed side by side; and again, the third, or ungual,
+phalanx may be distinguished at the first glance from the second by the
+shape of its free extremity, which is expanded in front into a rough
+surface shaped like an arrow-head for the support, not of the nail,
+but of the pulp of the finger. The inter-phalangeal joints reproduce
+on a smaller scale the pulley, or trochlea, and joint of the elbow,
+and present an analogous mechanism permitting only the movements of
+flexion and extension. In fact, as each of us may prove upon his
+own hand, while the fingers may be moved from side to side at their
+metacarpo-phalangeal articulations, the several phalanges can only be
+flexed and extended at the inter-phalangeal joints; in other words,
+while the finger enjoys great freedom of movement at its base, it only
+possesses that of flexion and extension in its component parts. Here
+again, and for the same reason, flexion is the more powerful movement.
+The movement of extension of the phalanges is<span class="pagenum" id="Page_96">[96]</span> limited, because the
+anterior portion of the articular capsule put on the stretch by the
+movement is stout and strong, but we find a great variety in different
+subjects, and with some, such mobility that the terminal phalanges can
+be bent backwards. Flexion is limited only by the contact of the soft
+parts on the anterior surface of a phalanx.</p>
+
+<p><i>The Proportions of the Upper Limb.</i>—Having examined the skeleton
+of the upper limb in relation to form and movement, it is necessary
+next to study its proportions—namely, to inquire, on the one hand,
+what comparison the length of the limb bears to the height, and, on the
+other, to compare the length of the different segments of the limb with
+each other.</p>
+
+<p>The comparison between the upper limbs and the height may be expressed
+in two ways: first, by examining the two arms outstretched in the
+horizontal position; the distance which then separates the extremity
+of one hand from that of the other is termed the <i>span of the upper
+limbs</i>, and this transverse measure includes not only the length of
+the arms, but also the breadth of the shoulders; secondly, by examining
+the upper limb hanging vertically beside the body, and noting to what
+level on the lower limb the extremity of the hand (nail of the middle
+finger) reaches.</p>
+
+<p>The relation of the span of the upper limbs to the height has been
+expressed long since by the formula known as the <i>square figure of
+the ancients</i> (Fig. <a href="#i_097">30</a>). If we draw two horizontal lines, one at the
+soles of the feet (<i>c</i>, <i>d</i>), the other at the summit of the
+head (<i>a</i>, <i>b</i>), and two vertical lines at right<span class="pagenum" id="Page_97">[97]</span> angles to
+the extremities of the two arms horizontally outstretched, these four
+lines form by their junction a perfect square; in other words, the man
+having the arms horizontal is enclosed within a square. This shows that
+the span of the arms is equal to the height.</p>
+
+  <div class="figcenter" id="i_097">
+     <img
+    class="p2"   
+    src="images/i_097.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 30.</p>
+     <p class="p0 sm center">Figure in a square, ancient method.</p>
+  </div>
+
+<p>This statement is correct for a man of the Caucasian race of the middle
+height, but it is not so for the yellow and black races, in whom the
+span of the arm is greater than the height. If from man we pass on to
+the anthropoid apes (chimpanzee, gorilla, &amp;c.), we find that the span
+of the arms in these becomes more and more extended as compared with
+the height. Thus, in the gorilla, the height being 5 ft. 7¼ in., the
+span becomes 8 ft. 9¼ in.; and in the chimpanzee, to a height of 5 ft.
+5¼ in. the corresponding span is 6 ft. 6 in.</p>
+
+<p>Again, when we examine the upper limbs hanging freely beside the body,
+we find that in the European of average height the extremity of the
+middle finger corresponds in general to the middle of the thigh; in
+subjects of short stature this extremity of the hand descends a little
+lower than the middle, and, on the other hand, in very tall men it
+ends at a higher level. In the yellow and<span class="pagenum" id="Page_98">[98]</span> black races the extremity
+of the hand descends much lower than the middle of the thigh; and in
+the anthropoid apes we find that, in the chimpanzee, the extremity of
+the hand descends below the knee; in the gorilla it corresponds to
+the middle of the leg; and, finally, in the orang-outang, and in the
+gibbon, it reaches almost to the ankle.</p>
+
+<p>If we seek among the various portions of the upper limb a part which
+would answer as a common measure between them, we cannot find anything
+satisfactory in this respect. The length of the hand, which would
+naturally seem to be indicated as a measure, is not contained an even
+number of times in the length of the bones of the shoulder, arm, or
+forearm. If, however, we take from the hand the length of the third
+phalanx of the middle finger, we have a measure equal to that of the
+vertebral border of the shoulder-blade, or of the clavicle. Under those
+conditions we may say that the length of the humerus is equal to twice
+that of the hand, and that of the forearm equal to one and a half the
+length of the hand; but these proportions are so variable that they
+cannot be insisted on. We should attach more importance to the rule
+that takes the hand as a common measure of the entire body in regard
+to height, taking the height as being equal to ten hands. This is a
+proportion which often answers in reality, but which presents too many
+exceptions to be laid down as a law.</p>
+
+<p>We may here state the fact once for all, that there is not an
+<i>absolute rule</i> for the anatomist, or system of proportions
+applicable to every class<span class="pagenum" id="Page_99">[99]</span> of subject, to those of small as well as
+those of large stature. If, on the contrary, an ideal proportion is
+adopted, in which a human figure has been altered, so as to correspond
+to the abstract conception of beauty, we say that this question of
+proportion belongs no longer to the domain of anatomy or observation,
+but that here we rather touch æsthetic doctrines; it is for this reason
+that we have limited ourselves, when putting forward various ideas of
+proportion, to indicating, within such limits as direct observation
+permits, whether a part of a limb might serve as a common measure for
+this limb or for the total length of the body.</p>
+
+  <div class="figcenter" id="i_099">
+     <img
+    class="p2"   
+    src="images/i_099.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 31.</p>
+     <p class="p0 sm center">The Egyptian Canon.</p>
+  </div>
+
+<p>The <i>Egyptian canon</i> as demonstrated by Charles Blanc, which has
+a certain historical interest, is that the <i>length of the middle
+finger</i>, taken as a common measure, should be contained nineteen
+times in the length of the body. In fact, the “Selection of Funeral
+Monuments” by Lepsius (Leipzig, 1852) contains the drawing of a very
+curious Egyptian figure, divided by transverse lines into nineteen
+parts (not including the head-dress). Now as several passages in
+different ancient authors seem to indicate that the Egyptian sculptors
+have taken the finger as the unit of the system, Charles Blanc very
+ingeniously remarks this fact, that in the figure in question, one<span class="pagenum" id="Page_100">[100]</span> of
+the horizontal lines, the eighth beginning at the soles of the feet,
+passes exactly at the base of the middle finger in the right hand
+(closed holding a key), while the seventh touches the extremity of the
+middle finger of the extended left hand. It seems to him, then, very
+probable that the distribution of these horizontal lines indicates a
+system of measuring the figure, and that the space between the seventh
+and the eighth line measures the length of the middle finger, which
+thus becomes the standard of this system of proportion. According
+to the Egyptian rule, the length of the middle finger will be found
+nineteen times in that of the height (Fig. <a href="#i_099">31</a>); it may be that this
+rule was adopted by the Greek artists, and Charles Blanc does not
+hesitate to think that Polycletus, who has composed a <i>Treatise
+on Proportions</i>, with a model in marble known by the name of
+<i>Doryphorus</i>, used no other system but the Egyptian; there has
+been always found in a number of antique figures this same proportion
+of nineteen times the middle finger to the height of the body, and in
+the Achilles, for example, the total height does not exceed by more
+than ¹⁄₂₀th of an inch the length of the middle finger multiplied by
+nineteen.</p>
+
+<p><i>Brachial Index.</i>—An interesting proportion to note is
+that between the arm and forearm, especially as it has been
+with anthropologists the subject of important researches, and
+will familiarise us with the term <i>index</i>, which we must
+frequently make use of, especially when comparing the transverse and
+antero-posterior diameters of the cranium. We give, in anthropology,
+the name <i>index</i> to the number which expresses the proportion
+of one dimension to some<span class="pagenum" id="Page_101">[101]</span> other, this last being represented by 100.
+Supposing, in fact, that we compare one length, <span class="allsmcap">A</span>, equal to
+one metre, with another length, <span class="allsmcap">B</span>, equal to two metres, in
+this case, the first length being half that of the second, we speak of
+the index found as 50 (because 50 is the half of 100, and we suppose
+the second length to be equal to 100). Now the forearm is shorter than
+the arm; it represents about three-fourths of it; if, then, we take the
+number 100 to represent the length of the humerus, the number 75, which
+is three-fourths of 100, would represent the length of the forearm; and
+then in denoting by the <i>brachial index</i> the proportion of the
+length (always shorter) of the forearm with that of the arm (always
+longer) we simply say that the brachial index is represented by 75.</p>
+
+<p>This method of notation, which reduces any numerical proportion to the
+decimal system, is very valuable, as it permits us to follow without
+difficulty the degree in which a proportion varies according to the
+race or species.</p>
+
+<p>Thus we come to speak of the brachial index (proportion of the forearm
+to the arm) as 75. We have chosen this particular number in order to
+make the example easy; in reality, in adult European subjects this
+index is only 74—that is to say, that the forearm is to the arm as 74
+is to 100. If we measure the same parts in the adult negro, and reduce
+to the decimal proportion the numbers obtained, we find the brachial
+index here is 79—or that the forearm is to the arm as 79 to 100. In
+the negro, then, the forearm is longer compared with the arm, as 79
+is a greater part of 100 than 74.<span class="pagenum" id="Page_102">[102]</span> Finally, if we pass on from the
+human species to the anthropoid apes, we see that the brachial index
+comes to be 80, and even 100—that is to say, that the length of the
+forearm becomes equal to that of the arm; and we know, therefore, that
+the great length of the upper limbs in the anthropoids (page 86) is
+principally owing to the greater length of the forearm. But the most
+interesting fact is that in the human race the brachial index is not
+the same at different ages—thus, in the European infant at birth this
+index is 80; before the end of the first year it is only 77, and by
+degrees during childhood it descends until it arrives at 74 in the
+adult. This clearly shows that the humerus, during the growth of the
+body, lengthens in proportion more than the bones of the forearm;
+so that they, which were at first to the humerus as 80 is to 100,
+come gradually to be as 77 to 100, and finally as 75 or 74 to 100.
+If we were to glance at comparative osteology we should see that, in
+such animals as the lion or the horse, the forearm becomes longer in
+proportion to the humerus, so as to equal, and afterwards to surpass,
+the length of that bone.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_103">[103]</span></p>
+
+<h2>CHAPTER IX.<br>
+<span class="subhed">THE PELVIS.</span></h2></div>
+
+<div class="blockquot">
+
+<p class="hangingindent">The bony structure of the hips.—The pelvis; <i>sacrum</i> (five
+vertebræ welded together); <i>coccyx</i> (the caudal appendage
+in man and the monkeys resembling man); the <i>innominate
+bones</i> (ilium, pubis, ischium); the cotyloid cavity; the
+acetabulum and its notch.—The articulations of the pelvis,
+sacro-iliac and pubic; sacro-iliac ligaments; ilio-pubic,
+or Poupart’s ligament (fold of the groin); ligaments of the
+hip-bones.—The pelvis as a whole.—Comparison of the pelvis in
+the male and female.</p>
+</div>
+
+
+<p>The pelvis is formed by the union of the two hip-bones, one on either
+side, with the vertebral column, so as to form the pelvic cavity or
+basin, which is bounded behind by the lower portion of the vertebral
+column, sacrum and coccyx, laterally by the hip-bones, and in front by
+the <i>symphysis pubis</i>, the antero-inferior articulation of the
+two hip-bones together. It completes the trunk and abdomen in their
+lower parts, and serves to articulate with the thigh-bones (femora)
+externally. There is a great contrast between the shoulder girdle and
+the pelvic girdle. The former is freely movable, and has only a slight
+attachment by the sterno-clavicular joint to the axial skeleton: the
+latter is immobile, and is firmly adherent to the vertebral column
+(sacrum) by means of the sacro-iliac joint and powerful accessory
+ligaments.</p>
+
+<p>The <i>os sacrum</i> (Figs. <a href="#i_028">5</a>, <a href="#i_033">8</a>, <a href="#i_104">32</a>, <a href="#i_108">35</a>, <a href="#i_114">38</a>), so called because it was
+the part of the trunk offered in sacrifice by the ancients to their
+gods, is formed of five vertebræ (sacral vertebræ) fused<span class="pagenum" id="Page_104">[104]</span> together
+by osseous union, the separate portions of which are easily seen on
+careful examination. Taken as a whole it forms a pyramid, the base
+of which (2, Fig. <a href="#i_108">35</a>) is turned upwards and forwards, corresponding
+to the body of the first sacral vertebra. This sacral pyramid, being
+directed obliquely from above downwards and backwards (Figs. <a href="#i_033">8</a>, <a href="#i_038">9</a>),
+presents a surface called antero-inferior, or rather inferior, on
+which we recognise five united vertebral bodies (Fig. <a href="#i_028">5</a>, page 28); a
+postero-superior surface—better called superior—on which we recognise
+the rudimentary spinous processes (Fig. <a href="#i_038">9</a>, page 38) and the laminæ of
+these same five vertebræ, these portions being all united together;
+and, finally, the lateral surfaces, expanded above to form the
+<i>auricular surface</i> for articulation with a similar surface on the
+hip-bone. This surface extends over the sides of the first three sacral
+vertebræ; and behind it are rough excavations for the attachment of the
+powerful posterior sacro-iliac ligaments.</p>
+
+  <div class="figcenter" id="i_104">
+     <img
+    class="p2"   
+    src="images/i_104.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 32.</p>
+     <p class="p0 sm center smcap">Section of the Pelvis.</p>
+  </div>
+
+<p>The <i>coccyx</i> (21, Fig. <a href="#i_028">5</a>), placed below the sacrum, is a
+rudimentary caudal appendage, but instead of<span class="pagenum" id="Page_105">[105]</span> being, as in the greater
+number of mammals, free and movable, it is found in man curved towards
+the interior of the pelvis, whose inferior outlet it contributes
+to close. Its borders give attachment to powerful <i>sacro-sciatic
+ligaments</i>, which help to fill up the space between the vertebral
+column and the hip-bone on each side.</p>
+
+  <div class="figcenter" id="i_105" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_105.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 33.</p>
+     <p class="p0 sm"><span class="smcap">The Hip-Bone of an Infant</span>: its three primitive
+pieces:—1, ilium;—2, its superior border;—5, 6, ischium, its
+acetabular part (in 7);—8, pubis, its acetabular part (11).</p>
+  </div>
+
+<p>The coccyx is formed of a series of four vertebræ, welded one with the
+other, and so diminished in size that each of them is reduced to a
+small osseous nodule, representing a rudimentary vertebral body.</p>
+
+<p>The <i>hip-bones</i> (<i>ossa innominata</i>) are two in number, one on
+each side, articulating behind with the sacrum, and uniting with each
+other in front (Figs. <a href="#i_108">35</a>, <a href="#i_114">38</a>) to form the symphysis pubis. In order to
+understand the arrangement of the parts of which a hip-bone consists
+it is necessary to notice that this bone is made up originally, in
+an infant, of three distinct parts, which are afterwards joined
+together as age advances; of these parts, the superior is called the
+<i>ilium</i>; the two others are inferior; that placed in front is
+called the <i>pubis</i>, and that behind, the <i>ischium</i> (Fig. <a href="#i_105">33</a>).
+The junction of the three parts is effected at the central portion of
+the bone, at the bottom of the great<span class="pagenum" id="Page_106">[106]</span> articular cavity of the hip-joint
+(acetabulum). The names of almost every part of the hip-bone are
+derived from its three constituent portions—namely, the <i>ilium</i>,
+<i>pubis</i>, and <i>ischium</i>.</p>
+
+  <div class="figcenter" id="i_107" style="max-width: 305px">
+     <img
+    class="p2"   
+    src="images/i_107.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 34.</p>
+     <p class="p0 sm"><span class="smcap">Right Hip-Bone</span> (external surface).—1, 1, iliac
+crest;—2, anterior superior iliac spine;—3, posterior
+superior iliac spine;—4, superior curved line;—5, inferior
+curved line;—7, anterior inferior iliac spine;—11, ischial
+spine;—12, great sciatic notch;—13, acetabulum; and 14, its
+pit (fovea);—16, its great notch, directed downwards;—17,
+spine of pubis;—18, horizontal ramus of pubis;—19, body and
+descending ramus of pubis;—20, 20, tuberosity of ischium;—22,
+obturator foramen.</p>
+  </div>
+
+  <div class="figcenter" id="i_108" style="max-width: 434px">
+     <img
+    class="p2"   
+    src="images/i_108.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 35.</p>
+     <p class="p0 sm"><span class="smcap">Pelvis of the Male.</span>—1, 1, iliac crests;—2,
+sacrum;—3, symphysis pubis;—5, 5, acetabula;—6, 6, rami of
+pubes and ischia;—7, 7, obturator foramina;—10, 10, iliac
+fossa.</p>
+  </div>
+
+<p>Examining first the external surface of the bone, we notice that its
+upper part is expanded into a large area called the <i>dorsum ilii</i>
+(5, Fig. <a href="#i_107">34</a>), which is crossed by three curved lines limiting the
+attachments of the gluteal muscles (4 and 5, Fig. <a href="#i_107">34</a>). Below this
+area the bone is narrowed and presents a circular cavity (13 and
+14, Fig. <a href="#i_107">34</a>), broad and deep, which has received the name of the
+<i>acetabulum</i> (a vinegar-cup); its use is to form the articular
+socket of the hip-joint for the reception of the head of the femur.
+The margin of this cavity is prominent throughout its entire extent,
+except below, where it is deficient, and gives rise to the <i>notch</i>
+of the acetabulum; this notch is a valuable starting-point to settle
+the natural position either of the iliac bone or of the entire pelvis
+(Fig. <a href="#i_107">34</a>). If, in fact, this bone of the pelvis is supposed to belong
+to a figure in the upright position, the acetabular notch should be
+directed downwards, as shown in Fig. <a href="#i_107">34</a>. Below the acetabulum the
+innominate bone is pierced by a large hole, called the <i>obturator</i>
+or <i>thyroid foramen</i> (22, Fig. <a href="#i_107">34</a>), bounded by the following
+parts: behind, by the <i>ischium</i> (20, Fig. <a href="#i_107">34</a>); in front and
+above, by the <i>horizontal ramus of the pubis</i> (18); below, by a
+bony plate formed by a prolongation of the pubis (19) proceeding to
+join a corresponding prolongation of the ischium. These united bars
+of bone are called the <i>descending ramus of the pubis</i> and the
+<i>ascending ramus of the ischium</i>, and they unite to form with<span class="pagenum" id="Page_107">[107]</span>
+those of the opposite side the <i>pubic arch</i> of the completed
+pelvis. The internal surface of the innominate bone is divided into
+upper and lower parts by a diagonal line—the <i>ilio-pectineal
+line</i>—which separates the iliac portion of the bone from the part
+formed by the ischium and pubis, and also serves to separate in the
+complete pelvis the upper abdominal part (<i>false pelvis</i>) from
+the cavity of the true pelvis below. Above this line is the internal
+expanded surface of<span class="pagenum" id="Page_108">[108]</span> the ilium known as the <i>iliac fossa</i> (10,
+Fig. <a href="#i_108">35</a>). At its posterior end is the <i>auricular surface</i> of
+the ilium, for articulation with the sacrum. Below it are, first, a
+flat surface corresponding to the floor of the acetabulum, and, lower
+still, the obturator foramen, bounded as we have already described.
+The borders of the hip-bone are distinguished (Fig. <a href="#i_107">34</a>) as superior,
+anterior, posterior, and inferior. The <i>superior border</i>, called
+the <i>crest of the ilium</i> (1, Fig. <a href="#i_107">34</a>), is thick and curved like
+an italic ∫; it is this which marks on the living model the outline of
+the hip—namely, the limit between the lateral part of the abdomen and
+the lateral part of the pelvis. It ends in front in the <i>anterior
+superior spine</i> (2, Fig. <a href="#i_107">34</a>), and behind in the <i>posterior
+superior spine</i> of the ilium. The anterior border begins at the
+anterior superior iliac spine, and presents in succession, from above
+downwards, a notch, then a prominence called the <i>anterior inferior
+spine of the ilium</i> (7, Fig. <a href="#i_107">34</a>), below which is a groove giving
+passage to the psoas muscle (see later) bounded on its inner side by
+the <i>ilio-pectineal<span class="pagenum" id="Page_109">[109]</span> eminence</i>; finally, this border is continuous
+with the <i>horizontal ramus of the pubis</i>, and ends internally
+in the <i>spine</i> and <i>crest of the pubis</i> (17, Fig. <a href="#i_107">34</a>).
+The posterior border of the bone is similarly marked by projections
+and notches. It is limited above by the <i>posterior superior spine
+of the ilium</i> (3, Fig. <a href="#i_107">34</a>), and below by the <i>tuberosity of
+the ischium</i>; and between these are two smaller projections—the
+<i>posterior inferior spine of the ilium</i> above, and the <i>spine
+of the ischium</i> below. The ischial spine serves to divide the
+border into two unequal notches, of which the superior, the larger,
+is called the <i>great sciatic notch</i> (12, Fig. <a href="#i_107">34</a>), and the
+inferior, the smaller, the <i>lesser</i> sciatic notch. Finally,
+the <i>inferior border</i> is formed by the rami of the pubis and
+ischium. We will finish the description of this bone by describing
+its four angles: the antero-superior (2, Fig. <a href="#i_107">34</a>) is formed by the
+anterior superior iliac spine; the antero-inferior (17, Fig. <a href="#i_107">34</a>) by
+the body of the pubis, which here presents a rough oval surface of
+considerable extent which articulates with the pubis of the opposite
+side to form the <i>symphysis pubis</i>; the postero-inferior angle
+(20, Fig. <a href="#i_107">34</a>) is formed by the tuberosity of the ischium; and finally,
+the supero-posterior, thick and flattened, presents on its outer side
+the posterior iliac spines, and on its inner side the large rough
+<i>auricular surface</i>, for articulation with the sacrum.</p>
+
+<p>In order to construct the pelvis, the two hip-bones are joined together
+(at the <i>symphysis pubis</i>), and also join the sacrum (sacro-iliac
+synarthrosis) by articulations which have nothing in common with those
+which we have already studied in the<span class="pagenum" id="Page_110">[110]</span> limbs—for example, the shoulder
+or elbow. In those articulations of the limbs the bones were in contact
+by smooth surfaces, which glided one upon the other without anything
+interposed between them; such articulations are characterised by
+their mobility. On the other hand, the sacrum is united on each side
+to the hip-bones, and the hip-bones themselves articulate in front
+with each other by rough surfaces, between which are placed plates,
+more or less thick, of fibro-cartilage (similar to the intervertebral
+discs), which, in consequence, do not allow them to glide one on the
+other, but closely join them together. These articulations, which bear
+the name of <i>synarthroses</i>, or <i>symphyses</i> (<i>σύν</i>,
+together; <i>φύομαι</i>, to weld), are remarkable not for mobility, but
+for rigidity. They are characterised by the possession, between the
+articulating bones, of plates of fibro-cartilage, which act as tough
+but elastic buffers. Behind, the two <i>sacro-iliac synarthroses</i>
+support the sacrum, which is firmly wedged in between the two bones of
+the hip, and is slung between them, while the strong ligaments placed
+above the joint permit the sacrum to support the weight transmitted
+to it by the vertebral column. In front and below, the <i>symphysis
+pubis</i> (3, Fig. <a href="#i_108">35</a>), besides having fibro-cartilage placed between
+the bones and adherent to them, is also strengthened by fibrous bands
+passing superficially from one bone to the other.</p>
+
+<p>These articulations weld the component parts of the pelvis (the sacrum,
+with the two hip-bones) into a complete basin; but, at the same time,
+owing to the elasticity of these joints, the pelvis<span class="pagenum" id="Page_111">[111]</span> can resist without
+injury the shocks which are transmitted to it by the vertebral column
+and the lower limbs. The sacro-iliac and pubic fibro-cartilages break
+and check the shock which is produced—when, for example, we jump from
+a height and alight on the soles of the feet.</p>
+
+<p>Besides the sacro-iliac joint and the articulation of the symphysis
+pubis, the pelvis also possesses other ligaments accessory or
+special to the hip-bone. The accessory ligaments are those which
+strengthen the sacro-iliac joint. Above the articulation are the
+<i>ilio-lumbar</i> ligament, passing from the transverse process of
+the last lumbar vertebra to the iliac crest at its posterior end, and
+the <i>sacro-vertebral</i> ligament, passing from the same transverse
+process to the lateral mass of the sacrum. Below the joint are the
+two <i>sacro-sciatic ligaments</i>, which, arising together from the
+side of the sacrum and coccyx in the form of a broad fibrous band,
+proceed outwards, and, diverging, are attached, one—the <i>great
+sacro-sciatic ligament</i>—to the tuberosity of the ischium, the
+other—the <i>lesser sacro-sciatic ligament</i>—to the spine of
+the ischium. These ligaments convert the sacro-sciatic notches into
+foramina, through which important muscles pass; and, but for this
+fact, these ligaments would not need mention here, as they do not
+appear superficially, being covered by the mass of the gluteal muscles.
+The <i>special ligaments</i> of the hip-bone are the <i>triangular
+ligament</i>, which is a membrane partly filling up the pubic arch;
+the <i>obturator membrane</i>, which almost completely fills the
+obturator foramen; and <i>Poupart’s ligament</i> (really derived<span class="pagenum" id="Page_112">[112]</span> from
+the aponeurosis of the external oblique muscle of the abdomen, which
+stretches between the anterior superior spine of the ilium and the
+spine of the pubis). It is immediately subcutaneous, and corresponds
+to the fold of the groin. The subcutaneous fascia is attached to the
+entire length of the ligament, and so creates a depression extending
+from the spine of the ilium to the pubis. This fold of the groin marks
+the limit between the skin of the abdomen and that of the thigh. As the
+deep fascial envelope of the thigh is attached to Poupart’s ligament
+in its whole length, it pulls on the ligament so as to make it convex
+downwards in the extended position of the lower limb.</p>
+
+<p>The whole pelvis is expanded above and narrower below, and the lower
+part of it is, for the most part, concealed from view in the living
+model. The lower limbs are attached on each side in such a manner that
+they approach each other at the lower part of the pelvis, so as to
+leave between them only a narrow interval—the <i>perineum</i>, which
+corresponds to the genital organs and the parts between the folds of
+the buttocks. But the upper outline of the pelvis is clearly marked
+throughout the whole of its extent: on each side the iliac crests,
+on the superior borders of the hip-bones, form a slightly undulating
+line, the middle portion of which is most elevated, while its anterior
+extremity inclines abruptly downwards to terminate at the anterior
+superior spine of the crest of the ilium, clearly seen in the model
+when the skin is not loaded with fat; in front, the pelvis presents an
+extensive curved outline with its concavity upwards, the central parts
+corresponding to<span class="pagenum" id="Page_113">[113]</span> the symphysis pubis, and the lateral parts formed by
+Poupart’s ligament on each side. This anterior outline of the pelvis
+forms the lower limit of the abdominal wall. This helps to give the
+anterior abdominal wall the form of a shield rounded at both upper
+and lower ends, a form which the ancients seem to have exaggerated
+in adopting for the epigastric pit a configuration rounded instead
+of oval, which is the shape it presents in the skeleton. We have
+previously (page 54) shown how, in numerous cases, the form adopted by
+the ancient sculptors is sufficiently justifiable.</p>
+
+  <div class="figcenter" id="i_113" style="max-width: 431px">
+     <img
+    class="p2"   
+    src="images/i_113.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 36.&emsp;&emsp;&emsp;&emsp;Fig. 37.</p>
+     <p class="p0 sm">Diagrams showing that the pelvis of the male (A) represents
+a long segment (<i>a, b, c, d</i>) of a short cone (<i>a, b,
+x</i>), while the pelvis of the female (B) represents a short
+segment (<i>a, b, c, d</i>) of a long cone (<i>a, b, x</i>).</p>
+  </div>
+
+<p>After having studied the pelvis with regard to its mechanism and its
+influence on external form, we ought now to examine it with regard
+to its proportions—namely, its transverse dimensions; but as the
+prominence of the hips is formed not only by the superior border of
+the iliac bones, but also by the great trochanters of the femur, this
+examination cannot<span class="pagenum" id="Page_114">[114]</span> be completed without reference to the relation of
+the bones of the thigh to the pelvis. For the moment, therefore, we
+must confine ourselves to the study of the proportions of the pelvis in
+the male and in the female skeleton.</p>
+
+  <div class="figcenter" id="i_114">
+     <img
+    class="p2"   
+    src="images/i_114.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 38.</p>
+     <p class="p0 sm center">Pelvis of the female.</p>
+  </div>
+
+<p>Generally speaking, the pelvis of the female is broader and shorter
+than that of the male; in the male (Fig. <a href="#i_108">35</a>) the superior transverse
+diameter, which is a line that passes through the most prominent
+portion of the crest of the ilium of one side to the corresponding part
+of the other, measures from 10 to 12 inches (on the average 11 inches);
+whilst in the female this line measures from 10¼ to 13¾ inches (on the
+average 12 inches). On the contrary, the height of the pelvis in man
+is about 8 inches, whilst it is not more than 7¼ inches in the female.
+Again, comparing (Figs. <a href="#i_108">35</a> and <a href="#i_114">38</a>) a male with a female pelvis, we see
+that the first is narrow, the second comparatively broad between the
+ischial tuberosities.</p>
+
+<p>If we suppose a line drawn at a tangent to the sides of the pelvis, we
+see that these lines must be prolonged downwards for a considerable
+distance in order to meet in the female pelvis, but that in the male
+pelvis they join at a shorter distance from the<span class="pagenum" id="Page_115">[115]</span> pelvic outlet. In
+order to reduce these facts to a simple formula we may say, therefore,
+that the <i>pelvis of a male represents a long segment of a short
+cone</i>, while <i>that of the female represents a short segment of a
+long cone</i>. The student is referred to Figs. <a href="#i_113">36</a> and <a href="#i_113">37</a>, which show
+this arrangement by means of a simple diagram.</p>
+
+<p>The particular details of shape which distinguish the pelvis in the
+two sexes are the following:—<i>The thickness of the walls</i>: in
+the male the bones of the pelvis are stronger, the iliac crests are
+thicker, more curved, and less expanded, and the different prominences
+for the insertions of muscles are better marked. The <i>pubic arch</i>,
+limited above by the symphysis, and on each side by the descending
+rami of the pubis, is very broad, and has everted edges in the female,
+in whom it assumes the form of an elliptical arch, while in the male
+(compare Fig. <a href="#i_108">35</a> and Fig. <a href="#i_114">38</a> at 3, 6, 6) this same arch is narrow and
+raised, and takes the form of a pointed arch. For the same reason
+the <i>tuberosities of the ischium</i> are wider apart in the female
+than in the male. The <i>spine of the ischium</i> in the female is
+turned backwards, and appears less obviously in the pelvic cavity. The
+<i>obturator foramina</i> are wide and triangular in the female, while
+they are narrow and oval in the pelvis of the male. The <i>sacrum</i>
+is relatively shorter and broader in the female than in the male.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_116">[116]</span></p>
+
+<h2>CHAPTER X.<br>
+<span class="subhed">THE THIGH, FEMUR, AND HIP-JOINT.</span></h2></div>
+
+<div class="blockquot">
+
+<p class="hangingindent">The femur: its superior extremity: <i>neck</i>, <i>head</i>,
+and <i>trochanters</i>.—Hip-joint, or <i>coxo-femoral
+articulation</i>; movements of the joint; limits of these
+movements; limits of extension (ilio-femoral ligament);
+adduction (ligamentum teres); the influence of atmospheric
+pressure (experiments of the brothers Weber).—The transverse
+dimensions of the hips and shoulder in the male and female; the
+various formulæ (ovoid of the ancients, ovoid and elliptical
+of Salvage); the correct formula; the inter-humeral and
+inter-trochanteric diameters; the inter-acromial and inter-iliac
+diameters.—The external form of the region of the hips and
+great trochanter in particular; the osseous prominences brought
+into relief on the surface as flat and depressed surfaces.</p>
+</div>
+
+<p>The femur (Figs. <a href="#i_117">39</a> and <a href="#i_132">43</a>), or bone of the thigh, is one of the long
+bones. It is the largest bone in the skeleton, and consists, like all
+the long bones, of a shaft and two extremities (Fig. <a href="#i_117">39</a>). In this
+chapter we have to consider its upper end, and its articulation with
+the hip-bone.</p>
+
+  <div class="figcenter" id="i_117" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_117.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 39.</p>
+     <p class="p0 sm"><span class="smcap">Vertical Section Of Femur.</span>—1, 1, 2, 2, the body of
+the bone with the medullary canal hollowed out;—3, the great
+trochanter, whence the neck is given off, terminating in the
+head;—4, inferior extremity of the bone.</p>
+  </div>
+
+<p>The upper extremity of the femur is composed of a <i>head</i>, a
+<i>neck</i>, and of two tuberosities (the <i>great</i> and <i>small
+trochanters</i>) placed at the junction of the neck with the body of
+the bone. The head of the femur (5, Fig. <a href="#i_132">43</a>) is regularly rounded, and
+forms three-fourths of a sphere. Its spherical surface, turned inwards,
+upwards, and forwards, is smooth and covered with cartilage, except at
+a pit (6, Fig. <a href="#i_132">43</a>) seen a little below and behind its centre, which
+gives attachment to the <i>ligamentum teres</i>—a strong fibrous band
+which connects the femur to the acetabulum.</p>
+
+<p><span class="pagenum" id="Page_117">[117]</span></p>
+
+<p>The neck of the femur (7, Fig. <a href="#i_132">43</a>), connecting the head with the
+shaft, is directed downwards and outwards in the form of a cylinder,
+flattened a little from front to back, to become attached to the
+upper extremity of the shaft of the femur at an obtuse angle, looking
+downwards and inwards (Fig. <a href="#i_117">39</a>). This angle which the axis of the neck
+makes with that of the body varies in different individuals. In the
+adult male it is about 135 degrees; in the female it is less open—that
+is, it approaches nearer to a right angle. This helps to increase the
+transverse diameter of the hips in the female. Again, in both sexes
+this angle approaches gradually to a right angle with the advance of
+age—a change that assists in shortening the total height in the aged.
+At the junction of the neck of the femur with the body of the bone are
+the two tuberosities, or trochanters—one situated above and to the
+outer side, called the <i>great trochanter</i> (3, Fig. <a href="#i_117">39</a>; and 8, Fig.
+<a href="#i_132">43</a>); the other situated below and to the inner side, at the junction
+of the neck and the shaft, called the <i>lesser trochanter</i> (10,
+Fig. <a href="#i_132">43</a>). The great trochanter is of large size, is quadrilateral in<span class="pagenum" id="Page_118">[118]</span>
+shape, and projects beyond the upper border of the neck. It presents
+on its surfaces and borders numerous impressions, for the insertion of
+the muscles of the buttock. The lesser trochanter, on the contrary, is
+smaller in size, mammillated or conical in shape, and gives attachment
+to the psoas and iliacus muscles only.</p>
+
+<p><i>The Hip-joint.</i>—The <i>ilio-femoral</i> or <i>coxo-femoral</i>
+articulation is formed by the reception of the head of the femur into
+the cavity of the acetabulum, in which it exactly fits. The edge of
+the cavity is surrounded by the <i>cotyloid</i> and <i>transverse
+ligaments</i>, which clasp the head of the femur and serve to deepen
+the cavity and narrow its orifice. The articulation is a ball and
+socket joint (enarthrosis). As we should expect from the form of the
+articular surfaces, every possible description of movement can take
+place: the head of the femur can glide in all directions in the cavity
+in which it is received, producing the movement of <i>abduction</i>
+(the inferior limb being carried outwards, away from the middle line),
+<i>adduction</i> (towards the middle line), <i>flexion</i> (forwards,
+the anterior surface of the thigh being brought towards that of the
+abdomen), <i>extension</i> (backwards), and rotation, of the femur,
+outwards and inwards. But these movements are variously influenced by
+the disposition of the ligaments of the joint. Some are limited, others
+are very extensive.</p>
+
+<p>The ligamentous apparatus of the hip-joint consists of a thick capsule
+of fibrous tissue, which arises from the margin of the cotyloid cavity
+and encloses the head and neck of the femur. The<span class="pagenum" id="Page_119">[119]</span> disposition of this
+capsule is very different in front and behind.</p>
+
+<p>The capsule is composed of superficial longitudinal fibres stretching
+from acetabulum to femur, and thickened, except posteriorly, to form
+strong ligaments; and deeper, circular fibres, which <i>alone</i>
+constitute the back part of the capsule—consequently the capsule
+is thinner and weaker at the back, where the circular fibres appear
+superficially—constituting the <i>zona circularis</i>, or <i>ligament
+of Bertini</i>. The posterior portion of the capsule consequently
+cannot at any time become tense. The movement of flexion, indeed, may
+be continued as far as possible without causing tension of the back of
+the capsule of the joint. It is for this reason we speak of flexion of
+the thigh as unlimited, and, in fact, it may be continued until the
+anterior surface of the thigh comes in contact with the abdomen.</p>
+
+<p>The other movements of the thigh at the hip-joint are limited by the
+several longitudinal ligamentous bands of the capsule. In front, the
+capsule of the joint is put on the stretch when the thigh is carried
+backwards during extension, and the movement is checked when it
+arrives at a certain point. This is due to the <i>ilio-femoral</i>, or
+<i>Y-shaped ligament of Bigelow</i>, which extends from the acetabular
+margin to the front of the neck of the femur, dividing as it descends
+into two bands. It is the most important ligament of the hip-joint.
+Owing to the strength of this ligament, the movement of extension
+can be limited and checked at any given moment. Now if we try the
+experiment on ourselves, having flexed the thigh on the abdomen and
+then gradually<span class="pagenum" id="Page_120">[120]</span> extend it, we shall perceive that the movement is
+arrested at the moment when the axis of the thigh is in a continuous
+line with that of the body (or if the subject is upright, when the
+thigh is vertical). If we repeat this experiment on the dissected
+subject, with the joint prepared, we see that the ilio-femoral ligament
+is relaxed when the thigh is flexed on the pelvis, and becomes tense
+in proportion as the bone is extended, and that this tension arrives
+at its maximum when the femur is found in a line with the trunk, and
+the ilio-femoral ligament presents an insurmountable obstacle to any
+further extension.</p>
+
+<p>It is true that a man in the upright position can move his thigh
+backward; but it is necessary to observe, if, for example, it is the
+right thigh which is carried backward, it is not in the right hip-joint
+that the movement takes place, but in the left; in other words, the
+trunk is flexed upon the left femur. We may therefore state that when
+the thigh is so extended as to be in the same continuous plane with the
+trunk, the thigh and trunk form one and the same piece, and the two
+parts are incapable of further extension; and, consequently, when one
+thigh is carried behind the vertical line, the trunk must be rotated to
+an equal extent on the opposite side.</p>
+
+<p>The ilio-femoral band plays also an important part in the maintenance
+of the erect attitude. Being stretched in extension of the thigh, the
+head and neck of the femur rest against it, and so the erect position
+can be maintained without excessive muscular exertion. The ilio-femoral
+ligament also, aided by the <i>pubo-femoral</i> band of the capsule,<span class="pagenum" id="Page_121">[121]</span>
+presents an obstacle to <i>abduction</i>, or the movement of the thigh
+outwards, in the upright position, when the ligament is tense. When the
+thigh is slightly flexed on the pelvis, and the ligament is relaxed
+abduction of the thigh becomes comparatively easy (Fig. <a href="#i_121">40</a>).</p>
+
+  <div class="figcenter" id="i_121">
+     <img
+    class="p2"   
+    src="images/i_121.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 40.</p>
+     <p class="p0 sm smcap center">Outline of Buttock and Thigh.</p>
+  </div>
+
+<p>The movement of <i>adduction</i>, or bringing of the thighs together,
+is limited by the <i>ilio-trochanteric</i><span class="pagenum" id="Page_122">[122]</span> band of the capsule, and
+by the <i>ligamentum teres</i>—a special ligament, not part of the
+capsule, contained within the joint. This movement becomes very easy if
+the joint is slightly bent. If we try the experiment on an articulation
+in which the ilio-femoral ligament is cut, we perceive that in the
+position of extension the movement of adduction is just as difficult
+as if the ligament were intact. This is due to the presence of the
+<i>ligamentum teres</i>. This ligament is attached by one extremity
+to the rough depression below and behind the head of the femur, and
+by the other extremity, which is bifurcated, to the margins of the
+acetabular notch. We have already seen that in the pelvis of a man in
+the upright position this notch looks directly downwards (page 106);
+the ligament in this position is also vertical, and is put on the
+stretch, as the two ligaments, so to speak, help to suspend the pelvis
+on the heads of the femora. Now, in the upright position, the femur
+being vertical, the movement of adduction could be produced only by a
+gliding movement of the head of the femur in the acetabular cavity;
+but this gliding movement cannot take place, as the head of the femur
+is kept in position by the tense, round, or suspensory ligament. If,
+on the contrary, the femur is slightly flexed, the round ligament will
+be found relaxed; this permits the gliding of the head in the cavity,
+and at the same time permits of adduction, a movement which may now
+be accomplished with ease. An experiment which proves these facts
+without giving an anatomical demonstration of them (obtainable only
+from<span class="pagenum" id="Page_123">[123]</span> a prepared subject) is very easy to accomplish upon oneself. If
+one stands perfectly upright, rigid, with the body thrown backwards as
+far as possible, it will be seen that it is almost impossible to bring
+the two thighs and knees close together. Adduction is almost entirely
+lost in this position, so that we should be unable to bring the knees
+together and crush a fragile body, such as an egg, placed between them.
+But if, on the other hand, we flex the thighs a little, or the trunk is
+bent on the thighs, adduction becomes extremely easy, and now we can
+knock the knees together without any difficulty.</p>
+
+<p>The hip-joint is remarkable for the fact that upon it we can most
+conveniently demonstrate a law which applies also to all the other
+articulations, but of which we have reserved the explanation until
+now—namely, the law relative to <i>the influence of atmospheric
+pressure in maintaining articular surfaces in contact</i>. Up to the
+present, in studying the articulations, we have spoken of the form of
+the articular surfaces, and from their outline we have been able to
+deduce the nature of the movements permitted in the joint; we have
+spoken of the ligaments which surround the joint, and from their
+arrangement we have been able to infer the limits imposed upon these
+movements. But we have not spoken of the conditions which enable one
+articular surface to glide upon another without separating, and which
+maintain the surfaces in intimate and permanent apposition. It might be
+thought that this function devolves on the ligaments, but this would
+be an error;<span class="pagenum" id="Page_124">[124]</span> it is <i>atmospheric pressure</i> which keeps up this
+contact.</p>
+
+<p>The head of the femur is fitted very exactly into the hollow of the
+acetabulum. In the first place, the head of the femur is in close
+contact with the cavity, the non-articular portion of which is filled
+up by adipose tissue. In the second place, the cotyloid ligament
+closely encircles the base of the head of the femur, and may be
+compared to the edges of a cupping-glass. Now, as a vacuum exists
+between the two articular surfaces, and the air cannot penetrate
+between them, they adhere very closely to each other, merely allowing
+one to glide on the other; but if by any means air is allowed to obtain
+access to the interior of the joint the bones naturally fall apart. The
+experiments which explain those facts were first demonstrated by the
+brothers Weber.</p>
+
+<p>We have felt it important to dwell here, once for all, on the important
+part which atmospheric pressure plays in the mechanism of joints.
+Analogous experiments show that this pressure plays comparatively
+the same part in other articulations in maintaining their articular
+surfaces in contact.</p>
+
+<p><span class="smcap">Measurements and Proportions of the Hips.</span>—To return to the
+study of the region of the hips, we must now examine the <i>transverse
+dimensions</i> of this region, and the <i>external forms</i> which
+result from the presence of bony prominences, especially the great
+trochanter of the femur.</p>
+
+<p>The <i>transverse distance</i> which separates the one great trochanter
+of the femur from the other should be compared with the distance
+between the heads<span class="pagenum" id="Page_125">[125]</span> of the humeri; in other words, we must compare the
+<i>diameter of the hips</i> with that of the <i>shoulders</i>.</p>
+
+<p>What strikes us most in this comparison, at the first glance at a
+series of skeletons, is the great projection which the hips form in
+the female. In order to express this difference, various formulæ have
+been proposed. In one such formula the trunk is regarded as a figure
+more or less regularly oval, of which one extremity corresponds to the
+shoulders, the other to the hips, and in the two sexes the diameter
+is greater at one end than at the other. The ancients expressed the
+formula in the following manner:—In the male and in the female the
+trunk represents an ovoid—that is to say, an oval similar to that of a
+figure of an egg having a greater and a smaller extremity. In the male
+this figure has its greater end above, while in the female the lower is
+the larger end. According to this formula, in the female the diameter
+of the hips exceeds that of the shoulders, while in the male it is the
+diameter of the shoulders which exceeds that of the hips. The formula,
+as regards the female at any rate, is evidently exaggerated. In fact,
+Salvage and Malgaigne proposed the following formula:—Allowing that
+the trunk of the male is an ovoid, with the greater extremity superior,
+the trunk of the female forms an ellipse—that is to say, a figure in
+which both extremities are of the same dimensions; so that while in the
+male the diameter of the shoulders exceeds that of the hips, in the
+female the diameter of the hips is just equal to it.</p>
+
+<p>Now this last formula also exaggerates the real proportions of the
+hips in the female. The correct formula is as follows:—In the
+male, as well as in<span class="pagenum" id="Page_126">[126]</span> the female, the trunk represents an ovoid with
+the greater diameter above; but while in the male the difference
+between the greater extremity and the smaller is very considerable,
+in the female this difference is very slight. We can see by actual
+measurements that in the female the diameter of the hips, though
+always less, differs very little from that of the shoulders. In the
+male, the distance from the head of one humerus to the corresponding
+part on the opposite side (<i>inter-humeral diameter</i>) is on the
+average 15¼ inches, and the measure taken from one great trochanter
+to the other (<i>inter-trochanteric diameter</i>) is 12¼ inches;
+a difference between the two diameters of about one-fifth. In the
+female, the inter-humeral diameter is on the average 13¾ inches; the
+inter-trochanteric diameter is 12½ inches; therefore there is between
+the two diameters a difference of about one-twelfth. These figures also
+serve to demonstrate that the diameter of the shoulders is greater in
+the male than in the female (15 to 14), and that inversely the diameter
+of the hips is greater in the female than in the male (12½ to 12¼); so
+that, accordingly, if a man and a woman of average stature are supposed
+to throw their shadow on the same portion of a screen, the shadow of
+the shoulders of the male would cover a much larger surface than the
+shadow of the shoulders of the female; and, on the contrary, the shadow
+of the hips of the woman would exceed the shadow of the hips of the
+man, but only to a very small extent.</p>
+
+<p>In the foregoing paragraphs we have dealt with<span class="pagenum" id="Page_127">[127]</span> the transverse
+hip-measurements as inter-trochanteric. There is, however, another
+method of measurement, which justifies to a certain extent the formulæ
+adopted by the authors previously mentioned; it consists in comparing
+on the skeleton in both sexes the diameter of the pelvis without the
+femora with the diameter of the shoulders without the humeri. In this
+instance the shoulders are represented by the <i>inter-acromial</i>,
+and the hips by the <i>inter-iliac diameter</i> (from one iliac crest
+to the other). Under these circumstances the exact measurements show
+that in the male the inter-acromial diameter is 12¾ inches, and
+the inter-iliac 11 inches; therefore, as in the other formula, the
+trunk, deprived of its members, still represents an ovoid, with its
+greater extremity superior. On the other hand, in the female, the
+inter-acromial diameter is 11½ inches, and the inter-iliac measurement
+is 12 inches; so that here the trunk, deprived of its members,
+represents an ellipse or an ovoid, with its greater extremity below,
+although the upper extremity differs very little in size from the
+lower. The fault of this method of measurement is that it does not
+explain things as they are. The artist does not contemplate the torso
+as otherwise than complete—that is to say, provided with the upper
+and lower limbs—and it is absolutely necessary to take into account
+the part which the head of the humerus and the great trochanter of the
+femur take in the formation of the contours of the shoulder and hips.
+We have thought it desirable, however, to demonstrate this mode of
+measurement, because of the clear illustration which it gives of the
+greater<span class="pagenum" id="Page_128">[128]</span> diameter of the female pelvis as compared with that of the
+male.</p>
+
+<p>If we arrange in a table the figures given above for the inter-humeral,
+inter-trochanteric, inter-acromial, and inter-iliac diameters in the
+male and in the female, or if, better still, we represent those figures
+by lines intended to express, on the profile of a man and that of a
+woman, the proportionate value of the diameters of the region of the
+shoulders compared with the diameters of the pelvis and the hips, we
+obtain two figures which express in a striking manner all that has been
+pointed out (Figs. <a href="#i_128a">41</a> and <a href="#i_128b">42</a>).</p>
+
+  <div class="figcenter" id="i_128a" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_128a.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 41.</p>
+     <p class="p0 sm center">Diagram comparing the diameters of the hips with the diameters
+of the shoulders in the male.</p>
+  </div>
+
+  <div class="figcenter" id="i_128b" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_128b.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 42.</p>
+     <p class="p0 sm">Diagram comparing the diameters of the hips with the diameters
+of the shoulders in the female.</p>
+  </div>
+
+<p>We see, in fact, that in the male subject (Fig. <a href="#i_128a">41</a>) the vertical
+lines (<i>y</i> and <i>y</i>) passing through the<span class="pagenum" id="Page_129">[129]</span> extremities of
+the inter-trochanteric (<i>d d</i>) and the inter-iliac (<i>c c</i>)
+diameters, both fall within the extremity of the inter-humeral (<i>b
+b</i>), and also the inter-acromial diameter (<i>a a</i>); on the
+contrary, in the female (Fig. <a href="#i_128b">42</a>) we find that these same vertical
+lines both fall within the extremities of the inter-humeral (<i>b
+b</i>), but on the outer side of the inter-acromial (<i>a a</i>)
+diameter.</p>
+
+<p><i>The Great Trochanter.</i>—A word is necessary concerning the
+influence of the great trochanter of the femur on the external form of
+the hip. Looking at the skeleton the great trochanter is seen to stand
+out so clearly and forms a projection so considerable that we should
+expect to see on the model a prominence corresponding to its shape.
+This, however, is not so. The gluteal muscles which proceed from the
+pelvis to be attached to the great trochanter are numerous and thick,
+and the fleshy bellies of the more superficial form a projection
+which is raised above the trochanter; while over the process they are
+replaced by tendons, more or less flattened, so that the trochanter
+is marked on the surface by a depression bounded by the muscles—the
+tensor vaginæ femoris in front, the glutei muscles above and behind.
+Below, the concave space corresponding to the great trochanter is
+continuous with the broad, flat surface which occupies the outer aspect
+of the thigh.</p>
+
+<p>There are many analogous cases where osseous projections are frequently
+marked on the external figure by a depression, and the reason is
+always the same as that just explained, that these osseous projections
+give insertion to muscles, the fleshy bellies of which give place to
+tendinous expansions at a little<span class="pagenum" id="Page_130">[130]</span> distance from them, and form by their
+thickness a raised surface round the prominence; in a general way,
+then, we may say that, with a few exceptions (such as the malleoli of
+the ankle-joints), wherever an osseous surface is covered over only
+by the skin, the muscles which surround this surface arise above its
+level, and in consequence the bone is marked by a depression, more or
+less pronounced as the subject is more or less muscular. Similarly, the
+middle portion of the sternum is marked superficially by a depression
+limited on each side by the swelling of the great pectoral muscles, and
+the internal surface of the tibia forms a long and broad groove when
+the anterior and posterior muscles of the leg are well developed.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_131">[131]</span></p>
+
+<h2>CHAPTER XI.<br>
+<span class="subhed">THE THIGH AND KNEE.</span></h2></div>
+
+<div class="blockquot">
+
+<p class="hangingindent">The bony structure of the thigh and knee.—Shaft of femur:
+its curvature; oblique direction; linea aspera.—Lower
+extremity of femur: condyles; inter-condyloid notch; patellar
+surface.—<i>Patella</i>: ligament of the patella.—Upper
+parts of the bones of the leg.—<i>Head of the Tibia</i>:
+tuberosities and tubercle.—Head of <i>fibula</i>.—Articulation
+of the knee; relation of the bones in flexion and
+extension.—Ligamentous apparatus; capsule; its laxity and
+extent in front, whence the facility and extent of movement in
+flexion; its strength and shortness behind, whence the limit of
+movement in extension.—Lateral ligaments of the knee: their
+special mechanism.—Lateral movements of the knee: crucial
+ligaments.—Form of the region of the knee: surface below the
+patella; projection of patella; ligament of patella.—Osseous
+projections on the external surface and the insertion of
+tendons.—Simplicity of the form of inner surface of the knee.</p>
+</div>
+
+
+<p>Having studied the upper extremity of the femur with regard to the
+articulation, proportions, and contour of the region of the hips, we
+shall continue the study of this bone by examining its <i>shaft</i>
+and <i>inferior extremity</i>, and this latter part brings us to the
+<i>articulation of the knee</i>.</p>
+
+<p>The shaft of the femur is not straight, but is distinctly curved, with
+its convexity forward and outwards. On the living model this convexity
+may be recognised in the form of the anterior surface of the thigh,
+which is distinctly convex in front and on the outer side, the muscles
+which cover the femur in front being disposed in such a manner as to
+increase this appearance still more, as their fleshy masses are grouped
+together in the<span class="pagenum" id="Page_132">[132]</span> middle line of the anterior region of the thigh.
+The outward projection is most marked in cases of excessive muscular
+development, and is consequently more obvious in the male than in the
+female, and is best shown in the limbs of athletes. Again, the femur,
+in the model when standing upright, is not directed vertically, but
+rather obliquely from above downwards and inwards (Fig. <a href="#i_132">43</a>), so that
+the superior extremities of the femur are placed at some distance,
+comparatively speaking, from each other, while the lower extremities
+come very near each other at the level of the knees. In the female
+this obliquity is more clearly marked than in the male, for the upper
+extremities of the two bones are in the former placed more widely
+apart, as we have already seen when demonstrating the relative diameter
+of the hips (inter-trochanteric diameter) in the female.</p>
+
+  <div class="figcenter" id="i_132" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_132.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 43.</p>
+     <p class="p0 sm"><span class="smcap">Left Femur</span> (posterior view).—1, 1, linea aspera;—2,
+2, its external superior bifurcation;—3, its internal superior
+bifurcation;—4, 4, its inferior bifurcations;—5, head of
+femur;—6, depression in the head giving insertion to ligamentum
+teres;—7, neck of femur;—8, great trochanter;—9, internal
+surface of great trochanter;—10, small trochanter;—11,
+external condyle;—12, internal condyle;—13, inter-condyloid
+notch;—14, 15, tuberosities surmounting each of these condyles.</p>
+  </div>
+
+<p><span class="pagenum" id="Page_133">[133]</span></p>
+
+<p>The shaft of the femur presents three surfaces—one anterior, one
+postero-external, and one postero-internal; and three borders, two
+lateral and one posterior. The two lateral borders are very rounded,
+not sharp; the posterior border, on the contrary, is very prominent,
+and forms a rough line, called the <i>linea aspera</i> (1, Fig. <a href="#i_132">43</a>),
+which gives insertion to a number of muscles. This linea aspera divides
+above into two <i>bifurcations</i> slightly diverging, of which the
+outer one (2, 2, Fig. <a href="#i_132">43</a>) proceeds towards the great trochanter
+(<i>gluteal ridge</i>), and the inner one passes towards the lesser
+trochanter. Below, the linea aspera bifurcates in the same manner, one
+of its branches going to the inner, the other to the outer condyle of
+the femur (4, 4, Fig. <a href="#i_132">43</a>).</p>
+
+<p>The <i>inferior extremity</i> of the femur is widely expanded, both in
+the transverse and in the antero-posterior diameter. When we examine
+the posterior aspect of this extremity (Fig. <a href="#i_132">43</a>) we see that it is
+formed by two large prominences directed backwards, which are termed
+the <i>external and internal condyles</i>. These project laterally, and
+the inner condyle is much more prominent than the outer. The inferior
+and posterior surfaces of these condyles are smooth and covered with
+articular cartilage; between them is a deep hollow behind called
+the <i>inter-condyloid notch</i> (13, Fig. <a href="#i_132">43</a>). When we examine the
+anterior surface of the lower end of the femur we see that the condyles
+are united, and their smooth and continuous articular surface, covered
+with cartilage, serves to articulate with the knee-cap. This is the
+<i>patellar</i> surface. This surface presents a<span class="pagenum" id="Page_134">[134]</span> depression in the
+middle line and two lateral lips, of which the external, continuous
+with the external condyle, is more prominent and rises higher than the
+internal, which is continuous with the internal condyle. These details
+are very important, for, as we shall see, the lips of the patellar
+surface show prominently beneath the skin when the knee is strongly
+flexed, and we can notice their differences in prominence and height.</p>
+
+<p>In forming the articulation of the knee, the lower end of the femur is
+in direct contact with the patella and the upper end of the tibia, and
+is connected (by ligaments) with the upper end of the fibula. We will
+now consider the patella and the upper extremities of the two bones of
+the leg.</p>
+
+<p>The <i>patella</i>, which has been compared to a disc (whence its
+name), is more nearly triangular in shape, presenting an anterior
+surface longitudinally striated and slightly convex, and a posterior
+surface moulded on the patellar surface of the femur, and forming an
+oval articular surface with a median ridge and two lateral hollows.
+The borders of the patella are three: two lateral oblique borders for
+the attachment of muscles and ligaments; and a base directed upwards,
+into which the tendon of the quadriceps extensor (and particularly
+the rectus femoris) is inserted. The apex of the bone is directed
+downwards, and attaches a strong ligament which is inserted into
+the tubercle of the tibia, and is termed the <i>ligament of the
+patella</i>. Properly speaking, this ligament is a continuation of the
+tendon of the rectus femoris muscle. The patella should be considered
+as a <i>sesamoid</i> bone, an<span class="pagenum" id="Page_135">[135]</span> osseous nodule developed in the
+substance of this tendon.</p>
+
+  <div class="figcenter" id="i_135" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_135.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 44.</p>
+     <p class="p0 sm"><span class="smcap">The two Bones of Left Leg</span> (anterior view).—1, shaft
+of tibia;—2, 3, its internal and external tuberosities;—4,
+spine of tibia;—5, tubercle of tibia;—6, shin;—7, lower end
+of tibia, with internal malleolus (8);—9, shaft of fibula;—10,
+its upper end;—11, its lower end or external malleolus.</p>
+  </div>
+
+<p>The leg, like the forearm, is composed of two bones. One, the larger of
+the two, is placed on the inner side (1, Fig. <a href="#i_135">44</a>)—the <i>tibia</i>,
+or <i>shin-bone</i>; the other, much shorter, is situated on the outer
+side, and a little behind—the <i>fibula</i> (9, Fig. <a href="#i_135">44</a>). As in the
+case of the two bones of the forearm, the bones of the leg end at
+different levels above and below. Above, the tibia rises higher than
+the fibula, and alone takes a direct part in the articulation of the
+knee; below, the fibula extends lower than the tibia—so that the outer
+ankle (<i>external malleolus</i>) descends lower than the inner one. We
+will now for a moment examine the upper extremities of the two bones.</p>
+
+<p>The upper extremity of the tibia is expanded from side to side, to form
+the <i>tuberosities</i> (internal and external), surmounted by two
+<i>articular surfaces</i>, external and internal (2, 3, Fig. <a href="#i_135">44</a>), for
+articulation with the corresponding femoral condyles. The non-articular
+interval between these two surfaces presents in its centre a projection
+like a bifurcated cone which<span class="pagenum" id="Page_136">[136]</span> is known as the <i>spine</i> of the
+tibia. In front of the spine and behind it are rough triangular
+surfaces for the attachment of the <i>crucial ligaments</i>.</p>
+
+<p>The circumference of the upper end of the tibia forms a broad rough
+margin for attachment of the capsule of the knee-joint. In front, it
+is prolonged downwards into a large triangular surface which ends in a
+rounded eminence, called the <i>tubercle</i> of the tibia, which gives
+insertion to the ligament of the patella previously mentioned. On the
+outer side and back of the external tuberosity is a rounded facet,
+smooth and covered with cartilage, and directed mainly downwards for
+articulation with the head of the fibula (10, Fig. <a href="#i_135">44</a>). Lastly, on the
+back of the bone is the <i>notch</i> of the tibia, separating the two
+tuberosities from one another.</p>
+
+<p>The upper end of the fibula forms (10, Fig. <a href="#i_135">44</a>) an irregular rounded
+knob. It is situated external to and rather behind the upper end of
+the tibia, and articulates, as already seen, by its upper surface with
+the outer tuberosity of the tibia. External to the articular surface
+is a smooth area for the attachment of the biceps tendon, and the
+long external lateral ligament of the knee. Behind this area is the
+<i>styloid process</i>, which gives attachment to the short external
+lateral ligament of the knee. The head of the fibula can be plainly
+felt through the skin, below and behind the head of the tibia.</p>
+
+<p>Such are the bony structures which take a direct (femur, tibia,
+patella) and indirect part (fibula) in the conformation of the
+knee-joint. In the living model, in the erect posture, the condyles of
+the femur rest by their inferior surfaces on the upper surface of the<span class="pagenum" id="Page_137">[137]</span>
+tibia, and the apposition of the articular surfaces is rendered more
+exact by the presence between the articular surfaces of the femur and
+tibia of two <i>semi-lunar fibro-cartilages</i>, which increase the
+depth of the tibial surfaces (5, 5, Fig. <a href="#i_139a">46</a>), so that the corresponding
+condyle of the femur is received into a true articular cavity. At the
+same time, the patella is closely applied to the confluent anterior
+surface of the lower end of the femur. When, on the other hand, the
+model is kneeling, or, more generally, when the leg is flexed (carried
+backwards), the patella, which is firmly fixed to the tibia by its
+ligament, glides downwards on the femur, and comes in contact with the
+lower part of its anterior surface at the same time that the posterior
+parts of the condyles in turn roll over the upper surfaces of the tibia.</p>
+
+  <div class="figcenter" id="i_137" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_137.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 45.</p>
+     <p class="p0 sm"><span class="smcap">The Articular Parts of the Knee</span> (antero-posterior
+section).—1, femur;—2, tibia;—3, fibula;—4, patella;—5,
+rectus tendon;—6, ligament of patella;—7, one of the crucial
+inter-articular ligaments;—8, 8, one of the muscles of the
+calf;—<i>a</i>, <i>a</i>, anterior part, and <i>b</i>,
+posterior part of the articular capsule;—<i>C</i>, adipose mass
+beneath patella.</p>
+  </div>
+
+<p>After this rapid sketch of the bones which enter into the formation
+of the knee-joint, we have now to study in detail its ligamentous
+apparatus. The ligamentous apparatus of the knee is essentially
+composed of a fibrous <i>capsule</i>, attached to the borders of the
+articular surfaces of the femur, patella, and tibia. It is strengthened
+on all sides by the<span class="pagenum" id="Page_138">[138]</span> tendons of muscles attached to these bones in the
+neighbourhood of the knee. Without entering into unnecessary detail, we
+must consider the arrangement of this capsule, and its disposition on
+its anterior, posterior, and lateral aspects, and then consider how it
+affects the movements of the knee-joint, rendering some movements easy
+and extensive, while it limits others or makes them almost impossible.</p>
+
+<p>In front (<i>a a</i>, Fig. <a href="#i_137">45</a>) the capsule is loose and expanded and
+is mainly formed by the insertion of the quadriceps extensor muscle
+into the patella, with its continuation to the tubercle of the tibia
+as the ligament of the patella. This arrangement accounts for the ease
+and extent of the movement of flexion. In this movement, the tibia
+being carried backwards, and drawing with it the patella in the relaxed
+condition of the quadriceps extensor muscle, the capsule of the joint
+is put on the stretch. It would curtail the movement of flexion if it
+were short and compact; but the capsule at this point is so expanded
+and loose that no increase of movement on the part of the leg can cause
+any tension. Thus flexion of the knee may be prolonged until the calf
+of the leg comes in contact with the posterior surface of the thigh.</p>
+
+<p>Behind, the capsule of the joint is short and thick, and consists of
+a strong <i>posterior</i> ligament. When the leg is flexed on the
+thigh, this ligament is relaxed; but as the leg passes from flexion
+to extension it becomes tense, and when extension has arrived at that
+point which brings the leg in direct continuation with the thigh, no
+further movement is possible in<span class="pagenum" id="Page_139">[139]</span> a forward direction, and the limb is
+therefore fixed in this position.</p>
+
+<p>There are, moreover, other important ligaments which act, and still
+more forcibly, in the same manner; namely, the internal and external
+lateral ligaments of the joint, which must now be considered.</p>
+
+  <div class="figcenter" id="i_139a" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_139a.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 46.</p>
+     <p class="p0 sm"><span class="smcap">The Knee</span> state of the lateral ligaments (<i>a</i>,
+<i>b</i>) during flexion.—1, femur;—2, condyle of femur;—3,
+tibia;—4, fibula;—5, 5, section of semi-lunar fibro-cartilage.</p>
+  </div>
+
+  <div class="figcenter" id="i_139b" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_139b.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 47.</p>
+     <p class="p0 sm"><span class="smcap">The Knee</span>: lateral ligaments tense during extension of
+the leg on the thigh (the distance, <i>a b</i>, is greater here
+than in preceding figure); for the lettering, see preceding
+figure.</p>
+  </div>
+
+<p>The <i>internal lateral ligament</i> is a broad band of fibres, which
+passes from the inner tuberosity of the femur over the inner tuberosity
+of the tibia to be attached to the upper part of the <i>shaft</i> of
+the tibia on the inner side. It helps to form the contour of the inner
+side of the knee.</p>
+
+<p>The <i>long external lateral ligament</i> is a rounded cord, very
+strong and quite distinct from the capsule. Its inferior extremity is
+not inserted into the tibia, but into the head of the fibula between
+the insertions of the biceps muscle (Figs. <a href="#i_139a">46</a>, <a href="#i_139b">47</a>, <i>a</i>, <i>b</i>).
+The most<span class="pagenum" id="Page_140">[140]</span> remarkable characteristic of these ligaments is that their
+upper ends, attached to the lateral surfaces of the condyles of the
+femur, are not inserted at the centre of the curve of the condyles,
+but at a point situated more posteriorly (<i>a</i>, <i>b</i>, Figs. <a href="#i_139a">46</a>
+and <a href="#i_139b">47</a>). During flexion these ligaments are therefore relaxed, but as
+extension is produced, as the tibia is carried forward on the curved
+surface of the condyles of the femur, these ligaments gradually become
+tense, their points of insertion becoming further and further apart,
+owing to the eccentric insertion of their superior extremities. When
+the leg reaches that position of extension in which it is in line with
+the femur, the tension of the lateral ligaments is such as to arrest
+its movement and completely fix the leg in relation to the thigh. This
+may be seen by comparing Figs. <a href="#i_139a">46</a> and <a href="#i_139b">47</a>. We see, then, that owing to
+the position of the anterior, posterior, and lateral ligaments of the
+knee-joint, the movement of flexion in this joint is very extensive,
+while that of extension is limited, as it cannot be prolonged further
+than the position which brings the leg into direct continuity with the
+thigh.</p>
+
+<p>These ligaments are also responsible for the amount of <i>lateral
+movement</i> and <i>rotation</i> possible in the knee-joint. This
+articulation being formed by two condyles, it is very evident that
+lateral flexion cannot be produced, for then it would be necessary for
+one of the condyles to become detached from the corresponding articular
+surface of the tibia. Lateral movement is thus impossible, but a
+slight gliding movement under certain conditions takes place between
+the condyle of the<span class="pagenum" id="Page_141">[141]</span> femur and the tibia, a movement produced by a
+<i>rotatory</i> movement, of which the other condyle forms the centre.
+These slight movements of rotation, which contribute to the motion
+by which we direct the point of the foot outwards or inwards, are
+impossible during complete extension, when the tibia is fixed on the
+femur by the tension of the lateral ligaments and the posterior part of
+the capsule, and all the parts have already arrived at their maximum
+of tension. But when flexion occurs, and especially when the leg is at
+a right angle to the thigh, as in the seated subject, slight movements
+of rotation of the leg become possible; they are of small extent, it
+is true, especially inwards; since it is easier for the knee to take
+part in the movement which turns the foot outwards, than that which
+turns it inwards. This difference between rotation inwards and outwards
+is due to the presence within the joint of two ligaments called the
+<i>crucial ligaments</i>, of which we will only mention that they arise
+from the upper end of the tibia, between the two articular surfaces
+(page 136), and, crossing one another, are attached above to the sides
+of the inter-condyloid notch of the femur on the corresponding surface
+of each condyle. This crossing of the two ligaments is increased by
+the rotation of the tibia inwards, as this movement tends to twist
+them one on the other, and fix the tibia, so as to prevent rotation of
+the leg inwards. On the other hand, rotation outwards unwinds these
+ligaments and renders them more relaxed; so that this movement could
+be very extensive if the lateral<span class="pagenum" id="Page_142">[142]</span> ligaments did not prevent too great
+displacement between the condyle of the femur and the corresponding
+surface of the tibia.</p>
+
+<p>There are still in relation to the knee-joint several anatomical
+particulars which must now be examined in relation to <i>the external
+form</i> of the living model.</p>
+
+<p>The posterior surface of the knee is covered by numerous muscles and
+tendons which form the boundaries of the ham or <i>popliteal space</i>;
+the study of this region will therefore be undertaken along with the
+description of the muscles of the leg and thigh. On the outer and inner
+surfaces, and on the front of the knee-joint, however, many details of
+outward form are caused solely by the osseous and ligamentous parts, to
+which we must now draw particular attention.</p>
+
+  <div class="figcenter" id="i_143" style="max-width: 322px">
+     <img
+    class="p2"   
+    src="images/i_143.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 48.</p>
+     <p class="p0 sm"><span class="smcap">Outlines of the Lower Limb.</span>—<span class="allsmcap">A</span>, From behind;
+<span class="allsmcap">B</span>, from the front; <span class="allsmcap">C</span>, from the outer side.</p>
+  </div>
+
+<p>The anterior surface of the knee alters in shape in the two positions
+of extension or slight flexion, and in forcible flexion. In forcible
+flexion we notice particularly the form of the articular lower end of
+the femur (see page 134). In extension we find on the anterior surface
+of the knee, in succession from above downwards, a <i>flat triangular
+space above the patella</i>, corresponding to the tendon of the rectus
+femoris muscle; next, the <i>prominence of the patella</i>, showing
+clearly beneath the skin its triangular shape, with the base above
+and apex below; the two superior angles of the patella are frequently
+very distinct in the form of two small rounded projections. Below,
+<i>the ligament of the patella</i> forms a longitudinal eminence in the
+middle line, reaching to the tubercle of the<span class="pagenum" id="Page_143">[143]</span> tibia, which is seen (in
+semi-flexion) as a large projection. But, again, we frequently perceive
+on each side of the ligament of the patella a slight, soft eminence,
+easily depressed, which corresponds<span class="pagenum" id="Page_144">[144]</span> to parts not yet mentioned. These
+are the thin lateral portions of the capsule (<i>lateral ligaments
+of the patella</i>), which extend from the sides of the patella and
+patellar ligament to the tibial tuberosities. These portions of the
+capsule (<i>c</i>, Fig. <a href="#i_137">45</a>) are thin, and cover a <i>large mass of
+adipose tissue</i>, which is prolonged into the interior of the joint
+(as the <i>alar ligaments</i>), and which forms packing for the
+articulation on either side of the ligament of the patella (6, Fig.
+<a href="#i_137">45</a>). When the quadriceps extensor muscle draws forcibly on the patella
+and its ligament, these compress this adipose mass to a much greater
+degree, so as to form a bulging on each side, and then the bilateral
+prominence in question is much more clearly marked.</p>
+
+<p>On the external lateral surface of the knee we note the osseous
+prominences of the <i>tubercle of the tibia</i> (seen here in profile)
+and its <i>external tuberosity</i>; behind and below, <i>the head of
+the fibula</i>; and above, the <i>external condyle of the femur</i>.
+To certain of these prominences are attached the tendons coming from
+the thigh, marked on the external surface of the knee by three strong
+vertical bands; viz.:—in front, the tendon of the patella (seen here
+in profile); behind, the tendon of the biceps femoris, proceeding to
+be inserted into the head of the fibula; and between them the part
+of the aponeurosis of the deep fascia of the thigh, which becomes
+narrow and thickened, and forms a true tendon—<i>the ilio-tibial
+band</i>—attached to the outer tuberosity of the tibia.</p>
+
+<p>The form of the internal aspect of the knee is simple. Here the
+internal condyle of the femur and the corresponding tuberosity of
+the tibia form<span class="pagenum" id="Page_145">[145]</span> together a large regular hemispherical surface. The
+internal lateral ligament forms a broad band (page 139), which sweeps
+over the inner tuberosity of the tibia, accompanied by the tendons
+of the sartorius, gracilis, and semi-tendinosus muscles, to become
+inserted into the upper portion of the shaft of the tibia. The ligament
+and tendons soften the outlines of the bones, and give a rounded
+contour to the inner side of the knee.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_146">[146]</span></p>
+
+<h2>CHAPTER XII.<br>
+<span class="subhed">THE LEG, ANKLE-JOINT, FOOT.</span></h2></div>
+
+<div class="blockquot">
+
+<p class="hangingindent">The bony structure of the leg.—<i>Tibia</i> and <i>fibula</i>:
+tibio-fibular articulation; absence of mobility in the fibula
+(differences between the leg and forearm: between the foot and
+hand, also in the quadrumanous monkeys). Inferior extremities of
+these bones: <i>tibio-fibular articulation</i>; the malleoli:
+comparison of the internal and external malleoli with regard
+to length, situation, and form.—The skeleton of the foot:
+<i>tarsus</i>, <i>metatarsus</i>, and <i>toes</i>.—Importance
+of the bony structure of the tarsus and its influence on the
+form of the foot: construction and arrangement of tarsus,
+posterior half: anterior half.—Articulation of the leg with the
+foot; movements of the foot.</p>
+</div>
+
+
+<p>The two bones of the leg are placed, as we have previously seen (page
+135), parallel to each other, the <i>tibia</i> on the inner side, the
+<i>fibula</i> on the outer side and somewhat behind (Fig. <a href="#i_147">49</a>). The
+<i>tibia</i> can be felt beneath the skin in its whole length. Its
+<i>shaft</i> is triangular in section, and therefore presents three
+surfaces and three margins (1, Fig. <a href="#i_147">49</a>): an internal surface covered
+only by the skin and appearing superficially as a long flat surface,
+broader above where it looks a little forward, and inclining directly
+inwards at its inferior part, where it becomes continuous with the
+prominence of the inner ankle or internal malleolus (Fig. <a href="#i_150a">50</a>, page
+150). The external surface is slightly concave in order to lodge the
+antero-external muscles of the leg, of which the principal is the
+tibialis anticus; below, this surface inclines forwards, following the
+course of the tibialis muscle, which, from the antero-external region
+of<span class="pagenum" id="Page_147">[147]</span> the leg, is directed towards the inner border of the foot (Fig.
+<a href="#i_150a">50</a>, page 150). The posterior surface of the tibia is entirely covered
+by the strong and numerous muscles of the posterior region of the leg.
+Finally, of the three margins of the shaft of the tibia the anterior is
+particularly prominent, and is known by the name of the <i>crest of the
+tibia</i> or <i>shin</i> (6, Fig. <a href="#i_147">49</a>).</p>
+
+<p>The <i>fibula</i> appears superficially, as already seen, in the
+region of the knee, at its upper end. Its lower end is also obviously
+subcutaneous at the outer ankle, where it forms the <i>external
+malleolus</i> (9, Fig. <a href="#i_147">49</a>). The shaft of the bone is long and
+slender, and is prismatic in form. It is curved from above downwards
+and forwards, and downwards and inwards. It serves the purpose of a
+strengthening bar for the tibia, at the same time that it increases the
+area for the attachment of the muscles of the leg. The shaft of the
+fibula is surrounded on all sides by these muscles.</p>
+
+  <div class="figcenter" id="i_147" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_147.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 49.</p>
+     <p class="p0 sm center"><span class="smcap">Bones of the Leg</span> (front view).</p>
+  </div>
+
+<p>The two bones are separated throughout their entire length by an
+interval called the <i>interosseous space</i> (Fig. <a href="#i_147">49</a>), broader above
+than below, and filled up by a fibrous membrane (<i>interosseous
+membrane</i>), which, passing from one bone to the other, still further
+increases the area for attachment of the muscles of the leg. Above,
+the<span class="pagenum" id="Page_148">[148]</span> fibula articulates with the postero-external surface of the
+superior extremity of the tibia, and this superior <i>tibio-fibular
+articulation</i> possesses a very slight gliding movement, exercised
+chiefly through the action of the biceps muscle in external rotation
+at the knee-joint. Below, the fibula is attached to the corresponding
+part of the tibia by a strong <i>interosseous ligament</i>, forming
+a symphysis, or <i>synarthrodial joint</i>. This <i>inferior
+tibio-fibular</i> articulation has hardly any mobility: it only gives a
+certain amount of elasticity to the ankle-joint, into which the foot is
+received. We see, therefore, that there is, with regard to mobility, a
+great difference between the bones of the leg and those of the forearm;
+in the forearm the radius is moveable on the ulna, and can turn in such
+a manner as to cross the latter, and produce the movements of pronation
+and supination of the hand. Between the fibula and the tibia there is
+no movement of the kind; the foot is not capable of any movement which
+may be compared to that which takes place in the hand during pronation
+and supination. We may say that it is the same with monkeys, in the
+class called quadrumana; they have not the power of pronation and
+supination of the foot, which, from this point of view, and also in
+every other respect, is properly speaking a foot and not a posterior
+hand, as their ancient name of <i>quadrumana</i> would lead us to
+suppose.</p>
+
+<p><i>Ankle-joint.</i>—By their junction the inferior extremities of
+the tibia and fibula constitute an articular cavity, which forms the
+ankle-joint, by their articulation with a bone of the tarsus—the
+<i>astragalus</i>.<span class="pagenum" id="Page_149">[149]</span> This <i>tibio-fibular</i> cavity possesses three
+sides, of which two, the superior and internal, are formed by the
+tibia, and one only, the external, by the fibula; the two lateral
+walls correspond to the two osseous parts which form the prominences
+of the ankles and which are known by the name of <i>malleoli</i>
+(<i>malleus</i>, a hammer). They are distinguished as the <i>internal
+or tibial</i> and <i>external or fibular malleoli</i> (Fig. <a href="#i_147">49</a>,
+page 147). As the internal ankle or malleolus (8) is of a form and
+situation very different to that of the external (11), it is important
+to note here the configuration of the bones by which the subcutaneous
+prominences are explained.</p>
+
+<p>The malleoli differ in their <i>level</i>, in their <i>situation</i>,
+and finally in their <i>form</i> (Figs. <a href="#i_150a">50</a>, <a href="#i_150b">51</a>). First, we see at a
+glance that the external or fibular malleolus (11) descends much lower
+than the internal malleolus (8). Second, with regard to the transverse
+plane of the two malleoli, just as the shaft of the fibula is situated
+behind and to the outer side of the tibia, so the same position is
+maintained by the inferior extremities of the two bones, and the
+external malleolus is on a plane posterior to the internal malleolus.
+A transverse line which passes through the centre of the internal
+malleolus, passes outwards in front of the anterior border of the
+external malleolus; and, on the other hand, a transverse line, passing
+through the centre of the external malleolus, passes inwards behind
+the posterior border of the internal malleolus. Thirdly, with regard
+to the differences of form, these are the direct result of the shape
+of the osseous parts. The malleolar portion of the tibia, or internal
+malleolus,<span class="pagenum" id="Page_150">[150]</span> is square, presenting a horizontal inferior border, and
+two vertical borders—one anterior, the other posterior. On the
+contrary, the malleolar portion of the fibula, or external malleolus,
+is triangular in shape, or rather like the head of a serpent; it
+terminates below in a pointed extremity, formed by the convergence of
+the two oblique borders—one anterior, the other posterior—of which
+the anterior is the more sloping.</p>
+
+  <div class="figcenter" id="i_150a">
+     <img
+    class="p2"   
+    src="images/i_150a.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 50.</p>
+     <p class="p0 sm center"><span class="smcap">Outline of Ankle and Foot</span> (inner side).</p>
+  </div>
+
+  <div class="figcenter" id="i_150b">
+     <img
+    class="p2"   
+    src="images/i_150b.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 51.</p>
+     <p class="p0 sm center"><span class="smcap">Outline of Ankle and Foot</span> (outer side).</p>
+  </div>
+
+<p><span class="pagenum" id="Page_151">[151]</span></p>
+
+<p>Before entering into a study of the articulation of the leg with the
+foot, or <i>ankle-joint</i>, we must glance at the bony structure of
+the foot as a whole, so as to understand properly the significance of
+the position of one of the bones (<i>astragalus</i>) in relation to
+this joint.</p>
+
+  <div class="figcenter" id="i_151">
+     <img
+    class="p2"   
+    src="images/i_151.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 52.</p>
+     <p class="p0 sm center"><span class="smcap">Outlines of the Foot</span> (A, Dorsum; B, Sole).</p>
+  </div>
+
+<p>Just as the hand is composed of three sets of bones—the carpus,
+metacarpus, and fingers—so also the foot is composed of a similar
+series—the <i>tarsus</i>, <i>metatarsus</i>, and <i>toes</i>;
+but while in the hand, where the function is principally that of
+prehension, the fingers are long and the carpus very short, in the
+foot, which serves as a base of support, the toes are comparatively
+short, while the tarsus, which corresponds to the carpus, is of
+considerable size; it forms, in fact, one-half of the length of the
+foot. In order to understand the form of the foot and its mechanism it
+is necessary to make a particular study of the bones which compose the
+tarsus.</p>
+
+<p>As the carpus in the hand is formed by two rows of bones, so also the
+tarsus is composed of two groups. In the hand the carpal bones are
+grouped in<span class="pagenum" id="Page_152">[152]</span> two more or less transverse rows. In the foot, on the other
+hand, the rows of tarsal bones are longitudinally arranged; and the
+inner row overlaps the outer row in relation to the back part of the
+tarsus. There are two bones in the outer row: the <i>calcaneum</i>
+or <i>os calcis</i> behind, which forms the prominence of the heel
+and rests on the ground below: and the <i>cuboid</i>, articulating
+with it in front and carrying anteriorly the two outer metatarsal
+bones and the two outer toes. The inner row consists of five bones:
+(1) the <i>astragalus</i> or <i>talus</i> behind, which articulates
+with the bones of the leg and helps to form the ankle-joint above,
+which rests below on the upper surface of the calcaneum, and which
+articulates in front with the <i>navicular</i> bone; (2) the navicular
+or scaphoid bone; and in front of this the three <i>cuneiform</i> bones
+(<i>internal</i>, <i>middle</i>, and <i>external</i>), which lie above
+and internal to the cuboid bone, and carry the three inner metatarsal
+bones and the three inner toes.</p>
+
+  <div class="figcenter" id="i_153" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_153.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 53.</p>
+     <p class="p0 sm"><span class="smcap">The Bones of the Foot</span>, seen from the dorsal
+surface.—1, astragalus (with its head and neck, 2);—3,
+calcaneum;—4, scaphoid;—5, internal cuneiform;—6, middle
+cuneiform;—7, external cuneiform;—8, cuboid;—9, the
+metatarsus;—10, 11, the two phalanges of the great toe;—12,
+13, 14, the first, second, and third phalanges of the other
+toes.</p>
+  </div>
+
+<p>After this brief sketch of the tarsus, and before entering into the
+details of the configuration of its parts and the whole taken together,
+having seen the particular place occupied by the <i>astragalus</i>, we
+must study its articulation with the tibia and fibula. The part of the
+astragalus which is received into the cavity between the malleoli, is
+formed by the posterior three-fourths (1, Fig. <a href="#i_153">53</a>) of the superior part
+of the bone, separated from the anterior fourth by a narrow portion
+called the neck (2, Fig. <a href="#i_153">53</a>). This articular part is in the form of a
+pulley, with the antero-posterior groove hardly perceptible, but the
+lips are prolonged over the sides of the bone,<span class="pagenum" id="Page_153">[153]</span> and come in contact
+with the corresponding parts of the internal and external malleoli. It
+is readily seen (Fig. <a href="#i_153">53</a>) that the articular surface of the astragalus
+is considerably wider in front than behind. The same is seen in
+the shape of the lower end of the tibia. The <i>tibio-astragaloid
+articulation</i> permits movement chiefly in the anterio-posterior
+plane, namely, movement forward (flexion of the foot) and backwards
+(extension). During flexion of the foot on the ankle the astragalus
+is received in the malleolar cavity as in a vice, and the result is
+that no lateral movement is possible. When, however, the foot is
+extended, and the toes are pointed, the narrower part of the articular
+surface of the astragalus comes into relation with the wider portion
+of the inter-malleolar articular surface, and the result is that in
+this position a certain amount of lateral movement of the foot at the
+ankle-joint is permitted, aided, it is true, by gliding movements
+taking place among the tarsal bones themselves. Of the movements of
+flexion and extension, that of extension is the most free, as it may
+be continued until the axis of the foot<span class="pagenum" id="Page_154">[154]</span> becomes continuous with that
+of the leg, and here it is arrested by the meeting of the posterior
+border of the joint with the projections on the posterior border of the
+astragalus; but the movement of flexion by which the dorsal surface
+of the foot is brought near the anterior surface of the leg is more
+limited, for it is impossible to cause the foot to make with the leg an
+angle less than forty-five degrees, opening upwards and forwards. This
+is accounted for by the shape of the articular surfaces. In proportion
+as flexion is produced, the larger part of the articular surface of
+the astragalus is wedged into the malleolar cavity; thus the movement
+of flexion is arrested, and the foot is fixed. We cannot carry flexion
+further without bursting asunder the tibio-fibular joint, just as we
+should split a piece of wood by driving violently into it a wedge
+larger than the cavity to be filled.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_155">[155]</span></p>
+
+<h2>CHAPTER XIII.<br>
+<span class="subhed">THE FOOT.</span></h2></div>
+
+<div class="blockquot">
+
+<p class="hangingindent">Bony structure of the foot.—Union of bones of tarsus;
+astragalus and calcaneum (canalis tarsi, or tunnel of the
+tarsus); astragalar articulations, inferior calcaneo-scaphoid
+ligament; special functions of astragalus in the mechanism of
+the foot.—The other articulations of the tarsus, and their
+movements. <i>Metatarsus</i> and <i>Metatarsal</i> bones;
+importance of fifth metatarsal with regard to form.—The
+<i>toes</i> and their <i>phalanges</i>.—Skeleton of the foot as
+a whole; form of the foot.—Plantar arch.—<i>Proportions of the
+lower limb</i>; the foot as a common measure of the lower limb
+and the height.</p>
+</div>
+
+
+<p>We will now examine briefly the bones of the <i>tarsus</i>, especially
+with regard to the details which mark their articulations. The inferior
+surface of the <i>astragalus</i> presents two articular facets,
+separated by a deep, oblique groove. These two facets correspond with
+two similarly situated on the upper surface of the calcaneum. The
+astragalus thus rests upon the calcaneum, but it is supported on the
+inner side by a projection of the calcaneum, known by the name of the
+<i>sustentaculum tali</i>; and the anterior facet for the astragalus
+is to be looked for on the upper surface of this projection (Fig. <a href="#i_153">53</a>,
+page 153). The two facets of the calcaneum are also separated by a
+deep groove. It follows, therefore, that when the astragalus is in its
+place, the groove of the astragalus and the calcaneum meet and form a
+kind of tunnel, which is called the <i>cavity of the tarsus</i>, or
+<i>canalis tarsi</i>. This cavity is filled up during life by a strong<span class="pagenum" id="Page_156">[156]</span>
+ligamentous band, which attaches the astragalus to the calcaneum, and
+is called the <i>interosseous ligament</i>. Placed between the two
+calcaneo-astragaloid articulations, one in front of it and the other
+behind, the ligament forms a sort of pivot, around which the movements
+between the astragalus and the calcaneum take place. It is round these
+joints as a centre that the movements take place by which the foot as
+a whole is turned inwards or outwards, and so that its outer and inner
+borders are elevated.</p>
+
+<p>We have next to consider the articulations of the calcaneum and
+astragalus with the other bones of the tarsus. The articulation of
+the anterior extremity of the calcaneum with the posterior surface of
+the cuboid presents an interlocked arrangement which is surrounded
+by strong ligaments, especially on its lower plantar surface (the
+<i>inferior calcaneo-cuboid ligaments</i>, or <i>long and short plantar
+ligaments</i>), so that between the calcaneum and the cuboid only a
+slight gliding movement takes place, and to all intents and purposes
+these two bones form one elastic piece. The plantar ligaments from
+their strength have an important influence on the maintenance of
+the arch of the foot. The cuboid bone articulates in front with the
+metatarsal bones of the fourth and fifth toes, so helping to complete
+the outer part of the contour of the foot. On the inner side of the
+foot the bones completing the tarsus in front of the astragalus are the
+<i>navicular</i> (or <i>scaphoid</i>), and the three <i>cuneiform</i>
+bones, <i>internal</i>, <i>middle</i>, and <i>external</i>, which
+in turn are related to the<span class="pagenum" id="Page_157">[157]</span> inner three metatarsal bones. The
+<i>astragalo-scaphoid articulation</i> deserves the closest attention.
+The head of the astragalus, so called from its prominent rounded shape,
+articulates with the navicular bone, which is prolonged internally
+into a prominent <i>tubercle</i>. Between the sustentaculum tali
+and this tubercle a very powerful ligament passes, on which a part
+of the astragalus rests. The ligament is called the <i>inferior
+calcaneo-scaphoid</i> ligament, or <i>spring</i> ligament, and by
+its means an articulation is completed between the three bones—the
+<i>astragalo-calcaneo-scaphoid</i> joint. The whole weight of the body
+may be supported by the inferior calcaneo-scaphoid ligament, which thus
+serves an important purpose in supporting the arch of the foot. This
+is the ligament which gives way in flat-foot. By these articulations
+the foot possesses the power of lateral movement, by which the toes
+are carried inwards or outwards, and the outer border of the foot is
+elevated and the inner border is depressed, or the reverse. On the
+other hand, the movements of flexion and extension take place chiefly
+at the ankle-joint, the articulation, previously explained, of the
+astragalus with the tibia and fibula.</p>
+
+  <div class="figcenter" id="i_158" style="max-width: 400px">
+     <img
+    class="p2"   
+    src="images/i_158.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 54.</p>
+     <p class="p0 sm"><span class="smcap">Right Foot</span> (internal border).—1, 2, 3,
+4, calcaneum;—5, 6, 7, astragalus;—8, posterior
+calcaneo-astragaloid articulation;—9, head and neck of
+the astragalus;—10, 11, navicular or scaphoid;—12,
+astragalo-scaphoid articulation;—13, 14, internal
+cuneiform;—15, articulation of the internal cuneiform with
+the scaphoid;—16, the articulation of the internal cuneiform
+with the metatarsal bone of the great toe;—17, the middle
+cuneiform;—18, its articulation with the scaphoid;—19, the
+first metatarsal bone;—20, the second metatarsal bone;—21, the
+articulation of the second metatarsal bone with the cuneiform
+bones;—22, sesamoid bone;—23, 24, the phalanges of the great
+toe; 25, 25, phalanges of the other toes.</p>
+  </div>
+
+<p>The navicular or <i>scaphoid</i> bone articulates in front with the
+three <i>cuneiform</i> bones, and the cuneiform bones articulate with
+each other by facets which are flat, but present rough surfaces towards
+their inferior or plantar portions intended for interosseous ligaments.
+Similar articulations exist externally between the scaphoid and
+external cuneiform, and the cuboid bone. It is sufficient to<span class="pagenum" id="Page_158">[158]</span> say that
+in all these articulations a slight gliding movement takes place, just
+sufficient to give a certain elasticity to the plantar arch, which they
+contribute to form. We may point out the peculiarities that are to be
+noted in each of these bones: the <i>scaphoid</i> or <i>navicular</i>
+bone is concave behind, convex in front, and is prolonged into a
+prominent tubercle, which can be felt at the middle of the inner
+border of the foot; the <i>cuboid</i> is quadrilateral or pyramidal
+in form, and has an oblique groove (14, Fig. <a href="#i_159">55</a>) on its inferior or
+plantar surface, which contains the tendon of the <i>long peroneal</i>
+muscle (see below); finally, the three <i>cuneiform</i> bones are
+distinguished, counting from within outwards, as the <i>internal</i>,
+<i>middle</i>, and <i>external</i> cuneiform (Fig. <a href="#i_153">53</a>, page 153); the
+middle cuneiform (6) is smaller than the others, and does not extend so
+far forward, so that in relation to it the line of the tarso-metatarsal
+joints forms a notch<span class="pagenum" id="Page_159">[159]</span> opening into the tarsus, into which the posterior
+extremity of the second metatarsal bone is received.</p>
+
+<p>In front of the tarsus is found the <i>metatarsus</i>, corresponding to
+the metacarpus of the hand, while the toes correspond to the fingers.
+We have only a few words to say about those portions of the skeleton
+which resemble the corresponding parts of the hand.</p>
+
+  <div class="figcenter" id="i_159" style="max-width: 400px">
+     <img
+    class="p2"   
+    src="images/i_159.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 55.</p>
+     <p class="p0 sm"><span class="smcap">Right Foot</span> (external border).—1 to 6, the
+calcaneum;—7, the tibial surface of the astragalus;—8, the
+lateral facet of the astragalus for the external malleolus;—9,
+the tunnel of the tarsus (canalis tarsi);—10, the posterior
+calcaneo-astragaloid articulations;—11, head and neck of the
+astragalus;—12, the scaphoid;—13, cuboid;—14, commencement of
+the groove on the inferior surface of the cuboid (for the tendon
+of the long peroneus muscle);—16, external cuneiform;—17,
+middle cuneiform;—18, the five metatarsal bones with their
+posterior extremities (19);—20, 21, 22, 23, fourth, third,
+second, and first metatarsal bones;—24 to 25, phalanges of the
+toes.</p>
+  </div>
+
+<p>The metatarsal bones, five in number, are long bones, each composed
+of a prismatic shaft and two extremities, one posterior or tarsal,
+more or less wedge-shaped; the other anterior or digital, forming a
+rounded, globular head which articulates with the base of a phalanx.
+The metatarsal bones are placed parallel side by side, but that of the
+great toe is not markedly shorter than its fellows like the metacarpal
+bone of the thumb, and the great toe does not possess anything like the
+same amount of mobility as the thumb. It is further directed straight
+forward so as to complete the straight line of the inner border<span class="pagenum" id="Page_160">[160]</span> of
+the foot. With regard to particular details, it is necessary to note
+in the first metatarsal (19, Fig. <a href="#i_158">54</a>) its large size, in the second
+(22, Fig. <a href="#i_159">55</a>), its greater length, for it passes behind the others (in
+entering into the notch which corresponds to the middle cuneiform), and
+it also exceeds them in length, so that the second toe is as a rule a
+little longer than the rest. In the fifth we must note the form of its
+tarsal extremity, prolonged behind into a process (19, Fig. <a href="#i_159">55</a>) which
+appears as a prominence at the middle of the outer border of the foot,
+and gives insertion to the <i>short peroneal</i> muscle. Lastly, it may
+be observed that all the metatarsal bones except the first are sloped
+inwards and forwards, to point as it were towards the great toe.</p>
+
+<p>The phalanges of the toes (Figs. <a href="#i_158">54</a> and <a href="#i_159">55</a>) resemble in number and
+arrangement the corresponding bones of the hand, only they are much
+shorter, especially those of the little toe, the two last of which are
+reduced to small osseous nodules, so that the fifth toe is always much
+shorter than the rest. The names of the phalanges are the same as in
+the hand (page 93).</p>
+
+<p><i>The Foot as a whole.</i>—The skeleton of the foot forms
+an <i>arch</i> which presents two curves or concavities, one
+antero-posterior, the other transverse. The <i>sole</i> of the foot
+forms a hollow which extends from the posterior extremity of the
+calcaneum to the anterior extremity of the metatarsal bones; but this
+plantar hollow is much more elevated on the inner side (Fig. <a href="#i_158">54</a>) than
+on the outer side (Fig. <a href="#i_159">55</a>). It is necessary, in other words, in order
+to understand the general form of the foot, to consider<span class="pagenum" id="Page_161">[161]</span> that its
+<i>dorsal surface</i> looks upwards <i>and outwards</i>, and the sole
+<i>downwards and inwards</i>. The <i>outer border</i> is thin, and
+comes almost in contact with the ground, its <i>inner border</i> is
+thick and is raised from the ground.</p>
+
+<p>The skeleton of a well-articulated foot placed upon a horizontal
+surface comes in contact with the flat surface only by the posterior
+extremity (<i>tuberosity</i>) of the calcaneum (heel), and by the heads
+of the metatarsal bones (the balls of the toes, Fig. <a href="#i_151">52</a>, page 151).
+When the foot is covered with its soft parts these points of contact
+are scarcely changed; for, except at the heel and the balls of the
+toes, we see that the greater part of the outer border of the foot
+touches the ground but lightly, unless the subject is carrying a heavy
+load, which, pressing upon the plantar arch, brings its elasticity into
+play and slightly flattens it. We shall mention later on the special
+structures (ligaments and tendons) which act as cords which bend the
+bow and maintain the plantar arch.</p>
+
+<p><i>Proportions of the Lower Limb.</i>—As we have already inquired into
+the ratio of proportions of the hand and upper limb, we shall now see
+if the foot can furnish any measurements relative to the <i>proportions
+of the body</i>. We find that we can make the foot, no more than the
+hand, a common measure for the body in general and for the inferior
+limb in particular. We must confine ourselves to such measurements as
+will apply to the average subject. Thus it is easy to perceive upon
+the skeleton that the distance from the upper margin of the head of
+the femur to the inferior border of the internal<span class="pagenum" id="Page_162">[162]</span> condyle is equal
+to twice the length of the foot; but this has no practical value—it
+cannot be used on the living body, as it is difficult to recognise the
+level of the upper part of the head of the femur. If, instead of the
+head of this bone, we take the superior border of the great trochanter
+(a part easily felt beneath the skin), we find that the length from the
+superior border of the great trochanter to the inferior border of the
+external condyle scarcely ever measures the length of two feet, as the
+great trochanter is upon a considerably lower level than the head of
+the femur.</p>
+
+<p>The leg, including the thickness of the foot, is not as much as twice
+the length of the foot—that is, the distance from the lower border of
+the internal condyle of the femur to the ground (or the sole of the
+foot); but it is interesting to observe that in general the length of
+the leg, plus the thickness of the foot, is equal to the distance from
+the great trochanter to the lower border of the external condyle; in
+other words, the centre point of the lower limb (starting from the
+great trochanter) corresponds exactly to the line of the knee.</p>
+
+<p>When we compare the length of the foot with the leg, beginning from
+below upwards, we find a regular proportion, and one of practical
+interest—viz. that the line from the ground to the middle of the
+patella usually measures twice the length of the foot.</p>
+
+<p>As a common measure of the height of the body, the foot does not give
+us a result that can be expressed by an even number. From the numerous
+researches of Leger on this question, the length of<span class="pagenum" id="Page_163">[163]</span> the foot is
+generally contained 6⅓ times in the total height. However, this number
+presents an interesting fact when we express this proportion by taking
+the third part of the foot for a unit; 6⅓ feet forming nineteen thirds
+of the foot, we see that the height of the body contains nineteen
+thirds of the foot. It is interesting to observe that the number 19 is
+precisely that which expresses the proportion that the middle finger
+bears to the height in the Egyptian canon, according to Charles Blanc.</p>
+
+<p>With regard to the foot itself, we need only say that the
+tarso-metatarsal line offers, on the skeleton, a simple means of
+dividing the foot. This line is oblique from within outwards and
+backwards; its inner extremity at the base of the first metatarsal bone
+divides the foot into an anterior and posterior half, while its outer
+extremity, at the base of the fifth metatarsal bone, divides it into a
+posterior one-third and anterior two-thirds.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_164">[164]</span></p>
+
+<h2>CHAPTER XIV.<br>
+<span class="subhed">THE SKULL.</span></h2></div>
+
+<div class="blockquot">
+
+<p class="hangingindent">The bony structure of the <i>head</i>; division into
+<i>cranium</i> and <i>face</i>. Study of the vault, or
+skull-cap. <i>Occipital</i> bone.—<i>Parietal</i> bone
+(parietal eminence and temporal ridge).—<i>Frontal</i> bone
+(frontal eminences, superciliary ridges: nasal eminences:
+supra-orbital arches).—<i>Temporal</i> bone: mastoid process;
+zygomatic process.—Sutures of the skull: sagittal suture;
+lambdoid suture; sphenoidal sutures.—General form of skull:
+long heads; round heads.—Cephalic indices; dolichocephalic,
+brachycephalic, and mesaticephalic skulls.</p>
+</div>
+
+
+<p>The <i>skeleton of the head</i> is formed of two parts intimately
+united to each other: one above and behind, formed for the most part of
+flat bones, simple in form, and called the <i>cranium</i>, containing
+the brain: the other below and in front, consisting of numerous
+bones, complex in shape, and constituting the bony structure of the
+<i>face</i>. The facial bones form the boundaries of the cavities which
+lodge the principal organs of sense and the apparatus of mastication.</p>
+
+<p>The <i>cranium</i>.—The cranium forms an egg-shaped box with its
+long axis directed from before backwards. It may be examined from
+its <i>base</i>, which we need not study here, or from above or from
+the side. The bones which enter into its construction are eight
+in number, viz. the <i>sphenoid</i> in the base and side wall,
+the <i>occipital</i> behind, the <i>frontal</i> in front, the two
+<i>parietal</i> above, and the two <i>temporal</i> bones on the sides.</p>
+
+  <div class="figcenter" id="i_165" style="max-width: 400px">
+     <img
+    class="p2"   
+    src="images/i_165.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 56.</p>
+     <p class="p0 sm"><span class="smcap">The Skull</span> (lateral surface).—1, frontal bone;—2,
+parietal;—3, occipital;—4, temporal;—5, the great wing of
+the sphenoid;—6, coronal suture;—7, lambdoidal suture;—8,
+9, parieto-temporal suture;—10, spheno-parietal suture—11,
+spheno-temporal suture;—12, fronto-sphenoidal suture;—13,
+curved line limiting the temporal fossa;—14, 15, 16, malar
+bone;—18, the superior maxillary bone, with the infra-orbital
+foramen (19);—20, 21, 22, the bones of the nose;—23, the
+lachrymal groove;—24, the nasal eminence;—25, the inferior
+maxillary bone;—26, the mental foramen;—27, the angle of the
+jaw.</p>
+  </div>
+
+<p>The <i>occipital</i> bone (3, Fig. <a href="#i_165">56</a>) forms the whole posterior part
+of the base and vault of the skull.<span class="pagenum" id="Page_165">[165]</span> The bone possesses two distinct
+parts, inferior and superior. The <i>inferior</i> part is more or less
+horizontal, and is pierced by a large foramen (<i>foramen magnum</i>)
+through which the cavity of the cranium communicates with that of
+the vertebral canal. In front of this foramen is the <i>basilar
+process</i> of the occipital bone; upon each side are the <i>occipital
+condyles</i>, by which the skull articulates with the vertebral
+column—namely, with the lateral masses of the atlas (pp. 31, 32).
+The <i>superior</i> part (3, Fig. <a href="#i_165">56</a>), called the <i>squamous</i> or
+<i>shell-shaped portion</i> of the bone, is more or less triangular
+in form, with the<span class="pagenum" id="Page_166">[166]</span> apex directed upwards. Its borders are hollowed
+out into numerous irregular denticulations, which work in with
+similar denticulations on the posterior borders of the parietal bones
+(7, Fig. <a href="#i_165">56</a>); and assist in forming the <i>lambdoidal suture</i>.
+The external or posterior surface is crossed about its middle by
+a <i>semicircular</i> crest (<i>the superior curved lines</i>) of
+which the centre forms a prominence called the <i>external occipital
+protuberance</i>. This prominence is placed below the most projecting
+point of the back of the skull. The superior curved lines separate the
+outer or posterior surface of the occipital bone into an upper smooth
+part, belonging to the vault, which is covered by the scalp, and a
+lower rough surface, to which the muscles of the neck are attached.</p>
+
+<p>The <i>parietal</i> bones (2 and 13, Fig. <a href="#i_165">56</a>) are placed on each side
+of the vault of the skull in front of the occipital bone. Quadrilateral
+in shape, each bone presents four denticulated borders, of which the
+superior articulates with the parietal of the opposite side, the
+posterior with the occipital (7, Fig. <a href="#i_165">56</a>), the anterior with the
+frontal (6), and the inferior, which is concave (8, Fig. <a href="#i_165">56</a>), with
+the temporal and (slightly) with the sphenoid bone. The parietal bone
+presents two points for notice on its external surface—1, near its
+centre a projection called the <i>parietal eminence</i>, better marked
+in young subjects than in the adult, which represents the place where
+the ossification of the bone commences; 2, below this prominence a
+curved line, the <i>temporal ridge</i>, slightly rough (13, Fig. <a href="#i_165">56</a>),
+which limits the temporal fossa and gives attachment to the temporal
+fascia.</p>
+
+  <div class="figcenter" id="i_167" style="max-width: 400px">
+     <img
+    class="p2"   
+    src="images/i_167.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 57.</p>
+     <p class="p0 sm"><span class="smcap">Frontal Bone</span> (anterior surface).—1, the frontal
+eminences;—2, 2, superciliary ridges;—3, nasal eminences;—4,
+4, supra-orbital notches;—5, 5, 6, 6, internal and external
+angular processes;—7, 7, nasal notches;—8, nasal spine;—9,
+9, orbital plates;—11, the superior border;—12, the lateral
+borders.</p>
+  </div>
+
+<p>The <i>frontal bone</i>, a single bone (1, Fig. <a href="#i_165">56</a>), like<span class="pagenum" id="Page_167">[167]</span> the
+occipital, presents, like it, a vertical and a horizontal part. The
+latter belongs to the base of the skull and to the face (9, 9, Fig.
+<a href="#i_167">57</a>), and forms the roof of the cavity of the orbit (see below). The
+vertical part forms the anterior and superior wall of the cranium. It
+has a rounded superior border (11, Fig. <a href="#i_167">57</a>) which articulates by its
+denticulated edge with the parietal bones and forms the <i>coronal
+suture</i> (6, Fig. <a href="#i_165">56</a>). The anterior superficial surface forms the
+forehead, and upon it we have to notice the following points:—1,
+the <i>frontal eminences</i> (1, 1, Fig. <a href="#i_167">57</a>), better marked in young
+subjects and in females than in the adult male; 2,<span class="pagenum" id="Page_168">[168]</span> below these,
+the <i>superciliary ridges</i> (2, 2, Fig, <a href="#i_167">57</a>), which are directed
+obliquely downwards and inwards, to end in two prominent bosses called
+the <i>nasal eminences</i>. These prominences are best marked in the
+adult, and owe their prominence to the fact that the thickness of the
+bone is hollowed out in this situation into two cavities called the
+<i>frontal sinuses</i>, which become more developed as the subject
+advances in age; 3, at the lower border of this part of the bone are
+the <i>supra-orbital arches</i> (4, 4, Fig. <a href="#i_167">57</a>), at the margin of the
+orbit. Curved, with the concavity downwards, each of these arches forms
+on the outer side an <i>external angular process</i> (6, 6, Fig. <a href="#i_167">57</a>),
+which articulates with the malar, or cheek-bone (15, Fig. <a href="#i_165">56</a>), and on
+the inner side an <i>internal angular process</i> (5, 5, Fig. <a href="#i_167">57</a>) which
+articulates with the nasal process of the upper jaw. Between the two
+internal angular processes is a median rough space called the <i>nasal
+notch</i> (7, Fig. <a href="#i_167">57</a>), into which are received the <i>nasal</i> bones
+(22, Fig. <a href="#i_165">56</a>). Each supra-orbital arch presents, at the junction of
+its middle and inner thirds, a small notch called the <i>supra-orbital
+notch</i> (Fig. <a href="#i_167">57</a>).</p>
+
+<p>The <i>temporal bones</i>, one on each side of the skull (4, 11, and
+31, Fig. <a href="#i_165">56</a>), are very complex in shape, but we shall study here only
+one portion. Each temporal bone is composed of two parts, one belonging
+to the base, and another belonging to the lateral wall of the skull;
+the part belonging to the base forming a pyramidal mass of very dense
+bone, called the <i>petrous portion</i>, which contains the delicate
+organs of the internal ear; while the part belonging to the lateral
+wall of the skull (4, Fig. <a href="#i_165">56</a>) rises up<span class="pagenum" id="Page_169">[169]</span> as an irregular osseous disc
+from the base of the petrous portion of the bone. An orifice, the
+<i>external auditory meatus</i> which leads into the petrous bone,
+is found about its centre (31, Fig. <a href="#i_165">56</a>). Taking this orifice of the
+auditory canal as a centre, we find on the external surface of the
+temporal bone—1, behind the auditory canal the <i>mastoid portion</i>
+of the bone (33, Fig. <a href="#i_165">56</a>), which articulates with the parietal and
+occipital bones, and is prolonged downwards as a conical process
+in the shape of a nipple (μαστός, a nipple) called the <i>mastoid
+process</i>; 2, above the auditory canal, the <i>squamous portion of
+the temporal bone</i> (4, Fig. <a href="#i_165">56</a>), a shell-like bone with a rounded
+border articulating with the inferior border of the parietal bone
+(8, Fig. <a href="#i_165">56</a>). In front is a process (20, Fig. <a href="#i_174">58</a>) which is directed
+horizontally towards the face and joins the malar bone (16, Fig.
+<a href="#i_165">56</a>). This process, connecting the cranium with the face, is called
+the <i>zygomatic process</i> (ζυγός, a yoke), and it forms with the
+corresponding part of the malar bone the <i>zygomatic arch</i>. The
+zygomatic process rises from the temporal bone by two roots (Fig.
+<a href="#i_167">57</a>), of which one sweeps backwards above the orifice of the external
+auditory canal and helps to form the temporal ridge; the other extends
+as a rounded ridge transversely inwards towards the base of the skull,
+and as the <i>eminentia articularis</i>, forms the anterior limit of
+the <i>glenoid cavity</i>, into which the condyle of the lower jaw is
+received. Finally, below the auditory canal, the temporal bone gives
+origin to the <i>styloid process</i> (32, Fig. <a href="#i_165">56</a>), long and slender,
+which gives attachment to certain ligaments and muscles of the neck.</p>
+
+<p><span class="pagenum" id="Page_170">[170]</span></p>
+
+<p>The <i>sphenoid bone</i> is one of the most important in the
+construction of the cranium, although as it chiefly occupies the middle
+of the base of the skull, it is not very obvious on the surface. It
+is the <i>great wing</i> of the sphenoid bone which assists in the
+formation of the <i>temporal fossa</i>.</p>
+
+<p>The bones of the cranium articulate with one another by denticulated
+borders, to which the name of <i>sutures</i> is given. As the artist
+needs to study the skull not only with regard to its superficial form,
+but also as an <i>object</i> which figures frequently as an accessory
+in still-life compositions, and as a true representation of these
+sutures contributes to give to the skull its exact physiognomy, we
+must not leave the subject without carefully pointing them out. It is
+necessary for our purpose to examine the skull on its upper and its
+lateral surfaces.</p>
+
+<p>The upper surface of the skull presents a suture in the middle
+line, antero-posterior and inter-parietal, called the <i>sagittal
+suture</i>. Behind, on a level with the superior angle of the
+occipital bone (7, Fig. <a href="#i_165">56</a>), this median suture becomes continuous
+with the occipito-parietal suture to which the name of the <i>lambdoid
+suture</i> is given-because it resembles the form of a Greek lambda
+(<b>Λ</b>). In front, the sagittal suture is met by the parieto-frontal
+suture (6, Fig. <a href="#i_165">56</a>), which forms a curved line, to which has been given
+the name of the <i>coronal suture</i>.</p>
+
+<p>On examining the skull on one of its lateral surfaces, we see that
+the sutures form in this situation a more complex design, because of
+the articulations of the bones entering into the formation of the
+<i>temporal fossa</i> (5, 10, 11, 12, Fig. <a href="#i_165">56</a>). This fossa is<span class="pagenum" id="Page_171">[171]</span> formed
+by the parietal, squamous portion of the temporal, frontal, and great
+wing of the sphenoid bones. It is limited: below by the zygomatic arch
+(malar and temporal), and above by the curved line of the temporal
+ridge, which marks the temporal, parietal, and frontal bones. The
+suture formed within the fossa, at a point called the <i>pterion</i>,
+is roughly <img src="images/thick_h.jpg" alt=""
+style="height:1em;  padding:0 0em 0 0em;"> or
+<img src="images/thick_k.jpg" alt=""
+style="height:1em;  padding:0 0em 0 0em;">-shaped, and is occasioned by the
+contiguous articulations of the parietal, sphenoid, frontal, and
+squamous portion of the temporal bones.</p>
+
+<p>We have said that the general form of the skull is egg-shaped, with its
+greater extremity behind. It is, however, a common observation that
+the skull may differ remarkably from what may be termed the normal
+shape. It may be excessively high, or low; excessively prolonged
+backwards or forwards, or the reverse. One of the best-marked and
+constant variations is in the ratio of width to length, from which
+the <i>cephalic index</i> is derived. This may be an individual
+peculiarity: for instance, of two brothers, one may be round-headed,
+the other long-headed. Or it may be a racial character: for example,
+the black races are long-headed, the yellow races are round-headed, and
+the white races have a cephalic index which may be one or the other, or
+intermediate between the two extremes.</p>
+
+<p>The cephalic index (index of breadth of the skull) is an important term
+in physical anthropology.</p>
+
+<p>As we have previously explained, respecting the proportions of the
+arm and forearm (<i>brachial index</i>, page 100), we understand by
+the name of index the<span class="pagenum" id="Page_172">[172]</span> number which indicates the proportion between
+a short and a greater length, the latter being considered as equal
+to 100—that is to say, the figures obtained by direct measurement
+being reduced to a decimal proportion. We find that in certain skulls
+the transverse diameter is relatively very short, seeing that it is
+represented by an index of 75 or less; and such skulls are known as
+<i>dolichocephalic</i> (δολιχός, lengthened; κεφαλή, head). Others
+present a transverse diameter which approaches the antero-posterior,
+since it is represented by an index of 80 or more, the antero-posterior
+measurement being 100. This cephalic index of 80 or more is called
+<i>brachycephalic</i> (βραχύς, short). Between these two types are the
+heads of intermediate form called <i>mesaticephalic</i>, of which the
+cephalic index is from 75 to 80. The importance of dolichocephalic,
+mesaticephalic, and brachycephalic types of skull in relation to racial
+characters has no doubt been exaggerated; but the fact remains that
+certain races are dolichocephalic, and that certain other races are
+brachycephalic. A greater difficulty arises in regard to mesaticephalic
+skulls, which are, after all, in a sense only “averages,” and which,
+occurring as they do so commonly in the Indo-European race, suggest
+that either they are due to individual peculiarity or to the mingling
+of racial characters—in either case weakening the value of skull
+measurements in the investigation of races.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_173">[173]</span></p>
+
+<h2>CHAPTER XV.<br>
+<span class="subhed">THE FACE.</span></h2></div>
+
+<div class="blockquot">
+
+<p class="hangingindent">The bony structure of the face.—<i>Orbital cavities</i>:
+margins; cavities.—<i>Nasal fossæ</i>: anterior
+orifice.—Prominence of the <i>cheek</i>; malar bone and its
+processes.—<i>Upper jaw.</i>—<i>Lower jaw</i>; body; ramus;
+sigmoid notch, coronoid process, and condyle: variations
+with age.—The <i>teeth</i>: parts; names (incisors,
+canines, premolars, molars), number; relative dimensions of
+incisors.—Articulation of the lower jaw.—The face and skull as
+a whole with regard to form.—<i>Facial angle of Camper</i>; its
+measure; its proper value according to race; its exaggeration
+in the antique.—Proportions: the head as a common measure:
+law of eight heads; variations according to the height of the
+individual; point which corresponds to the middle of the body.</p>
+</div>
+
+
+<p><i>The Face.</i>—Instead of describing the bones of the face
+separately we will group them together around the cavities which they
+circumscribe and the prominences which they form. We will therefore
+study successively the <i>cavity of the orbit</i>, the orifice of the
+<i>nasal fossæ</i>, the prominence of the <i>cheek-bone</i>, and,
+lastly, the region of the <i>mouth</i>, along with which we will
+describe the <i>teeth</i>, the <i>lower jaw</i>, and its articulation
+with the base of the skull.</p>
+
+<p><i>The orbits.</i>—The orbits are two cavities situated symmetrically
+one on each side of the upper portion of the face below the forehead.
+Each of these cavities is formed like a pyramid with four sides, of
+which the apex penetrates backwards towards the cranial cavity, and
+of which the base, turned forwards, forms the orbital opening. This
+opening, or <i>orbital margin</i>, is of quadrilateral form with
+rounded angles (Fig. <a href="#i_174">58</a>), limited by an internal border (7) and an
+external border, both almost vertical, by a superior<span class="pagenum" id="Page_174">[174]</span> border (3) and an
+inferior border, both oblique, from above downwards and outwards.</p>
+
+  <div class="figcenter" id="i_174" style="max-width: 369px">
+     <img
+    class="p2"   
+    src="images/i_174.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 58.</p>
+     <p class="p0 sm"><span class="smcap">The Bony Structure of the Face.</span>—1, the frontal
+bone;—2, the nasal eminence;—3, supra-orbital notch;—4,
+the optic foramen;—5, the sphenoidal fissure;—6, the
+spheno-maxillary fissure;—7, the lachrymal groove;—8, the
+partition and opening of the nasal fossæ;—9, the infra-orbital
+foramen;—10, the malar bone;—11, the symphysis of the
+jaw;—12, the mental foramen;—13, the ramus of the lower
+jaw;—14, the parietal bone;—15, the coronal suture;—16,
+the temporal bone;—17, the temporo-parietal suture;—18, the
+great wing of the sphenoid;—19, the origin of the temporal
+ridge;—20, the zygomatic arch;—21, the mastoid process.</p>
+  </div>
+
+<p>The superior border is formed by the supra-orbital arch of the
+frontal bone (3, Fig. <a href="#i_174">58</a>) previously described, which presents the
+supra-orbital notch; the inferior border is formed by the <i>superior
+maxillary</i> and <i>malar</i> bones; a little below its centre is
+a hole, called the <i>infra-orbital</i> foramen (9, Fig. <a href="#i_174">58</a>), which
+is placed in the upper jaw almost in the same vertical line as the
+supra-orbital notch above the orbit (page 168). The internal border
+is formed by the junction of the internal angular process of the
+frontal bone with the ascending (nasal) process of the superior maxilla
+(Figs. <a href="#i_165">56</a> and <a href="#i_174">58</a>). Behind the inferior part of this border is a deep
+groove, called the <i>naso-lachrymal groove</i> (7, Fig. <a href="#i_174">58</a>), for
+the accommodation of the lachrymal sac (for the tears), which is the
+commencement of a canal (<i>naso-lachrymal canal</i>)<span class="pagenum" id="Page_175">[175]</span> connecting the
+orbit with the corresponding nasal fossa, and serving to transmit the
+nasal duct. Finally, the external border is formed by the junction of
+the external angular process of the frontal with the superior process
+of the <i>malar bone</i>, or bone of the cheek (10, Fig. <a href="#i_174">58</a>; 14 and 15,
+Fig. <a href="#i_165">56</a>).</p>
+
+<p>The cavity of the orbit has for its walls the osseous plates belonging
+to the frontal (superior wall) and the several bones of the face we
+have previously mentioned when describing the orbital opening. We
+need not enter here into the description of these surfaces and of the
+several special bones which compose them. We shall only say that the
+internal wall is directed from before backwards, while the external
+wall is oblique, from behind forwards and from without inwards. We
+note, lastly, at the deepest part (towards the apex) of the cavity,
+three apertures, by which the orbit communicates with deeper cavities;
+first, a circular orifice called the <i>optic foramen</i> (4, Fig.
+<a href="#i_174">58</a>); then, on the outer side of these, two fissures directed outwards,
+one obliquely upwards (<i>sphenoidal fissure</i>, 5, Fig. <a href="#i_174">58</a>), and the
+other obliquely downwards (<i>spheno-maxillary fissure</i>, 6, Fig.
+<a href="#i_174">58</a>). The two first communicate with the cranial cavity; the last-named
+fissure leads into the spheno-maxillary fossa.</p>
+
+<p>The <i>orifice of the nasal fossæ</i> (8, Fig. <a href="#i_174">58</a>) is situated in
+the middle of the face below the level of the orbits. It is somewhat
+heart-shaped (with the base downwards); it is bounded below by the two
+superior maxillary bones which unite in the middle line and form the
+<i>anterior nasal spine</i>, upon the sides by the same bones, and
+above by the two small<span class="pagenum" id="Page_176">[176]</span> <i>nasal</i> bones (Fig. <a href="#i_165">56</a>, page 165) wedged
+in on each side of the middle line between the nasal processes of the
+maxillary bones, and articulating above with the nasal notch of the
+frontal bone.</p>
+
+<p>Below, and to the outer side of each orbit, is the prominence of the
+cheek formed by the <i>malar bone</i> (10, Fig. <a href="#i_174">58</a>). This bone is
+formed like a star with four rays. The <i>superior</i> or <i>orbital
+process</i> (15, Fig. <a href="#i_165">56</a>) joins the external angular process of
+the frontal bone; the <i>anterior process</i> (17, Fig. <a href="#i_165">56</a>) forms
+with the superior maxillary the inferior boundary of the orbit; the
+<i>posterior</i> or <i>zygomatic process</i> (16, Fig. <a href="#i_165">56</a>) is directed
+backwards to form by its union with the zygomatic process of the
+temporal bone, the <i>zygomatic arch</i>; the <i>inferior</i> angle is
+reduced to a prominent margin which joins with the body of the bone
+to form the <i>prominence of the cheek</i>. This prominence is due to
+the projection of a <i>malar process</i> of the upper jaw on which the
+malar bone is fitted.</p>
+
+<p>There remain now only two bones to examine on the skeleton of the
+face—namely, the two bones which bound the cavity of the mouth and
+support the teeth: these are the superior and inferior maxillary or
+jawbones. The <i>superior maxillary bone</i> (18, Fig. <a href="#i_165">56</a>) has been in
+a great measure described already in relation to the orbital and nasal
+openings. The following points remain to be noticed: 1. The external
+surface is divided by a ridge descending from the malar process, into
+two surfaces—one outer, belonging to the zygomatic fossa, and the
+other anterior, appearing on the face. The facial surface is again
+subdivided into two smaller fossæ—the <i>canine fossa</i>, in which
+occurs the infra-orbital foramen, and the <i>incisive fossa</i>, above<span class="pagenum" id="Page_177">[177]</span>
+the incisor teeth—by a ridge (the <i>canine ridge</i>) which is
+formed by the prominent fang of the canine tooth. 2. The inferior or
+<i>alveolar</i> border presents a series of cavities for the lodgment
+of the roots of the upper teeth. The presence of these cavities is
+marked on the surface of the alveolar border by a series of prominences
+separated by depressions corresponding to the partitions between the
+alveoli.</p>
+
+  <div class="figcenter" id="i_177" style="max-width: 350px">
+     <img
+    class="p2"   
+    src="images/i_177.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 59.</p>
+     <p class="p0 sm"><span class="smcap">The Inferior Maxillary Bone</span> (side view).—1, the
+body of the inferior maxillary bone and its external oblique
+line;—2, the ramus;—3, the symphysis of the chin;—4, the
+mental foramen;—8, the angle of the jaw;—10, coronoid
+process;—11, the condyle;—12, sigmoid notch;—I, incisor
+teeth;—<i>c</i>, canine tooth;—<i>b</i>, bicuspid;—<i>m</i>,
+molar teeth.</p>
+  </div>
+
+<p>The <i>inferior maxillary bone</i> or <i>mandible</i> (Fig. <a href="#i_177">59</a>)
+requires more detailed consideration than the other bones of the face,
+as it takes so direct a share in the surface form that we may say that
+all the details of its shape are marked in the configuration of the
+chin and lower parts of the cheeks. It is originally composed of two
+distinct halves, one right and one left, which are joined together in
+early life in the middle line of the chin to form the symphysis of
+the chin, or <i>mental process</i> (11, Fig. <a href="#i_174">58</a>). It is sufficient to
+describe one of these halves as we see it in a side view of the skull
+(Fig. <a href="#i_165">56</a>).</p>
+
+<p>We see that each half is formed of two strong osseous plates joined
+together at an angle more or less approaching a right angle, of which
+the prominence directed downwards and backwards is called<span class="pagenum" id="Page_178">[178]</span> the <i>angle
+of the jaw</i>. The horizontal portion of the bone is called the
+<i>body</i>; the vertical portion is the <i>ramus</i>.</p>
+
+<p>The <i>ramus</i> consists of a flat external surface, which is
+continued below into the body of the bone (2, Fig. <a href="#i_177">59</a>). Its posterior
+border is thick, and is continued downwards to the angle of the jaw.
+The anterior border, which is thinner, is grooved, and terminates
+by joining below the upper alveolar border of the body of the bone.
+The borders of the groove join the oblique lines on the surfaces of
+the body of the bone. The superior border is divided by a deep notch
+(<i>sigmoid notch</i>, 12, Fig. <a href="#i_177">59</a>) into two very prominent parts.
+The posterior prominence is thick, and forms the neck, surmounted by
+the articular head, or <i>condyle</i>, of the jaw (11, Fig. <a href="#i_177">59</a>), for
+articulation with the temporal bone; the anterior prominence is in
+the form of a triangular plate, and bears the name of the <i>coronoid
+process</i> (10, Fig. <a href="#i_177">59</a>); it gives insertion to the temporal and
+masseter muscles.</p>
+
+<p>The <i>body</i> of the lower jaw extends from the angle to the
+<i>symphysis</i> of the chin (3, Fig. <a href="#i_177">59</a>); it has an external surface
+marked by an oblique line, above which is an orifice (12, Fig. <a href="#i_174">58</a>;
+and 4, Fig. <a href="#i_177">59</a>) called the <i>mental foramen</i>, placed in the
+same vertical line as the supra-orbital notch and the infra-orbital
+foramen. It is situated about the level of the second premolar tooth.
+The inferior border of the bone is thick and rounded; its superior
+<i>alveolar</i> border presents sockets for the teeth, and externally a
+series of prominences and depressions corresponding to the alveoli and
+the intervals between them.</p>
+
+<p>The character of the lower jaw changes with<span class="pagenum" id="Page_179">[179]</span> age; in the infant,
+the angle is very obtuse and but slightly prominent: in the adult
+it becomes almost a right angle: in the aged the form of the jaw is
+changed by the loss of the teeth and by the absorption of the alveolar
+border, causing a diminution of height in the body of the bone. In
+order, therefore, to bring the two jaws in contact with one another,
+the lower jaw requires to move strongly forwards and upwards, whence
+occurs a characteristic prominence of the chin in the aged, which seems
+to project upwards and forwards to meet the prominence of the nose.</p>
+
+<p>The teeth of the adult are altogether thirty-two in number—eight in
+each lateral half of each jaw. Each tooth is composed of a part fixed
+in the alveolar cavity called the <i>root</i>, and a free part called
+the <i>crown</i>. The form of the crown permits the division of the
+teeth into four distinct classes, which in each half of the jaw are
+arranged in the following manner, beginning from the median line:—Two
+<i>incisors</i> (I, Fig. <a href="#i_177">59</a>), one <i>canine</i> (<i>c</i>, Fig. <a href="#i_177">59</a>),
+two <i>premolars</i>, or <i>bicuspids</i> (<i>b</i>, Fig. <a href="#i_177">59</a>), and
+three <i>molars</i> (<i>m</i>, Fig. <a href="#i_177">59</a>)—total, eight. Situated at the
+most external and posterior portion of the dental arch, the premolar
+and molar teeth are hidden by the cheeks, and we need only mention
+that they are characterised by a crown formed of numerous tubercles
+(two for the premolars, four or five for the molar teeth). On the
+other hand, the canine and incisor teeth are easily seen when the lips
+are separated. The <i>canine</i> teeth are characterised by a conical
+crown with a sharp extremity, which is very large and prominent in the<span class="pagenum" id="Page_180">[180]</span>
+carnivora—<i>e.g.</i>, in the dog (whence the name of canines). The
+<i>incisors</i> present a crown flattened from before backwards, and
+rectangular in form (square). Their relative size is so constant that
+it should be stated here. The two largest are the median incisors of
+the upper jaw; next in order come the lateral incisors of the upper
+jaw, then the lower lateral, and finally the lower median incisors,
+which are the smallest. The lower incisors, besides being smaller, are
+characterised by their chisel-like cutting edge, which is bevelled at
+the expense of the outer surface.</p>
+
+<p>The articulation of the lower jaw with the skull, or
+<i>temporo-maxillary articulation</i>, is formed by the articulation
+of the condyle of the jaw (11, Fig. <a href="#i_177">59</a>; and 29, Fig. <a href="#i_165">56</a>) with the
+glenoid cavity of the temporal bone—a cavity placed in front of the
+external auditory meatus, and behind the <i>articular eminence</i>—the
+transverse root of the zygomatic process (page 169). This <i>glenoid
+cavity</i>, together with the articular eminence, is lined with
+cartilage, and is separated from the condyle of the jaw by an
+inter-articular fibro-cartilage. These structures are enclosed in a
+fibrous capsule which surrounds the articulation, and is strengthened
+on the outer side by a stout external lateral ligament, attached
+obliquely from a tubercle at the root of the zygoma downwards and
+backwards to the outer side of the condyle of the jaw. Therefore,
+when the jaw is depressed by a movement of rotation of the mandibular
+condyle upon its axis, this external lateral ligament is made tense,
+and draws the condyle forward, causing it to leave the glenoid cavity
+and<span class="pagenum" id="Page_181">[181]</span> come in contact with the articular eminence. Thus, when the mouth
+is widely opened (the lower jaw being greatly depressed) there is
+a displacement of the condyle of the jaw forwards, which is easily
+seen in thin subjects, and which should be noted here with its own
+particular mechanism.</p>
+
+<p>The face, as a whole, presents a special interest when we compare its
+configuration with that of the cranium, in various individuals and
+races. In general, the more prominent the skeleton of the face the less
+the cranium (the forehead) is developed. This was the idea of Camper, a
+Dutch anatomist and artist, about the middle of the eighteenth century.</p>
+
+  <div class="figcenter" id="i_181" style="max-width: 350px">
+     <img
+    class="p2"   
+    src="images/i_181.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 60.</p>
+     <p class="p0 sm"><span class="smcap">The Measurement of the Facial Angle</span> (goniometer
+applied to a skull).—1, the inferior horizontal plane of the
+goniometer;—2, movable piece with a pin introduced into the
+auditory meatus;—4, graduated circle;—5, the oblique plane
+attached below by a hinge to the horizontal;—6, the rack for
+placing the bar (7) on the prominent part of the forehead.</p>
+  </div>
+
+  <div class="figcenter" id="i_182" style="max-width: 350px">
+     <img
+    class="p2"   
+    src="images/i_182.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 61.</p>
+     <p class="p0 sm"><span class="smcap">The Facial Angle of a Skull of the Caucasian Race</span>
+(after Camper).—<i>a b</i> and <i>c d</i>, the lines which mark
+this angle (see the text);—1, the auditory meatus;—2, anterior
+nasal spine;—3, the most prominent part of the forehead.</p>
+  </div>
+
+<p>Camper proposed to measure the relative proportions of the cranium and
+face by the angle which the plane of the profile of the face makes with
+that of the base of the skull. This facial angle has since<span class="pagenum" id="Page_182">[182]</span> been the
+subject of much study on the part of anatomists and anthropologists,
+who have modified and perfected the process of measurement. It will be
+sufficient here to show what Camper’s idea was, and that, apart from
+anatomical considerations, he designed to furnish artists with a means
+of giving character to the different physiognomies of men and animals.
+This angle is determined by two planes (upon a head seen in profile, by
+two lines): one plane, which we may call horizontal, proceeds from the
+external auditory meatus to the anterior nasal spine, and corresponds
+to the inferior border of the orifice of the nasal fossa (1, Fig. <a href="#i_181">60</a>;
+and <i>a</i>, <i>b</i>, Fig. <a href="#i_182">61</a>); the other, directed obliquely upwards
+and backwards, is at a tangent below to the prominence of the incisor
+teeth, and above to the most prominent part of the forehead (<i>c</i>,
+<i>d</i>, Fig. <a href="#i_182">61</a>). Fig. <a href="#i_181">60</a> gives an idea of the apparatus with which
+we measure the facial angle at the present day. It represents the
+facial goniometer<span class="pagenum" id="Page_183">[183]</span> of Jacquart. The mode of measurement here differs
+from that employed by Camper, in that the inferior or horizontal plane
+passes forward not by the nasal spine, but by the prominence of the
+incisor teeth.</p>
+
+<p>Figures <a href="#i_182">61</a> and <a href="#i_183">62</a>, which are reproduced from those of Camper, show on
+the one hand that while the facial angle is never equal to a right
+angle, it approaches to it in the best types of the white race.</p>
+
+  <div class="figcenter" id="i_183" style="max-width: 350px">
+     <img
+    class="p2"   
+    src="images/i_183.jpg"
+     alt="">
+     <p class="p0 sm center smcap">62.</p>
+     <p class="p0 sm center"><span class="smcap">The Facial Angle of a Negro</span> (after Camper). The figures are
+the same as in the preceding.</p>
+  </div>
+
+<p>The ancients sought by an exaggeration to idealise the profile of the
+human face, and by increasing the fulness of the forehead they have
+given to heads of gods and heroes a facial angle as large as ninety
+degrees (Fig. <a href="#i_184">63</a>). These figures show, also, the decrease of the facial
+angle in proportion as we pass from the white to the yellow and black
+races:—“The angle which the facial line or characteristic line of the
+visage makes,” said Camper, “varies from seventy to eighty degrees in
+the human species. All who raise it higher disobey the rules of art
+(from imitation of the antique); all who bring it lower fall into the<span class="pagenum" id="Page_184">[184]</span>
+likeness of the monkeys. If I cause the facial line to fall in front
+I have an antique head; if I incline it backwards I have the head of
+a negro; if I cause it to incline still further I have the head of a
+monkey; inclined still more, I have that of a dog; and, lastly, that of
+a goose.”<a id="FNanchor_6" href="#Footnote_6" class="fnanchor">[6]</a> The figures which explain these ideas are as follows:—The
+facial angle of Camper averages 80 degrees in the Caucasian race; 75
+degrees in the yellow, or Mongol; 60 to 70 degrees in the Negro; 31
+degrees in the great monkeys (gorilla); lastly, 25 degrees in the head
+of a Newfoundland dog.</p>
+
+  <div class="figcenter" id="i_184" style="max-width: 320px">
+     <img
+    class="p2"   
+    src="images/i_184.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 63.</p>
+     <p class="p0 sm center"><span class="smcap">The Facial Angle of an Antique Head</span> (Apollo
+Belvedere)—(Camper).</p>
+  </div>
+
+<p>In our study of the various segments of the limbs we have seen that
+some of them have been chosen, in different systems of measurement, to
+serve as a common measure for these limbs, and for the entire body.
+Thus we have spoken of the canons which respectively take as a unit
+the <i>hand</i> (contained about ten times in the height of the body),
+the<span class="pagenum" id="Page_185">[185]</span> <i>foot</i> (contained a little more than six times in the total
+height), the <i>middle finger</i> (contained nineteen times), &amp;c., &amp;c.
+It is true, also, that the head—<i>i.e.</i>, the vertical distance
+from its summit to the base of the chin—may be taken also as a common
+measure. This was done long ago. Vitruvius, speaking of the proportions
+of the human body, states that the height of the head should be the
+eighth part of the whole body. Leonardo da Vinci, Albert Dürer, and J.
+Cousin have followed the rule of the Latin author; and the law which
+makes the head the eighth of the total height has for a long time
+past become classic in all the schools. The choice of the head as a
+unit seems sufficiently justified by the two facts that, on the one
+hand, in every representation of the human body the head is always
+visible, and forms a part distinct from the rest of the body, and that,
+admitting that it makes the eighth part of the height, this number is
+particularly convenient, not being too great; and, on the other hand,
+it is divisible by two. In this respect it offers, for example, a great
+advantage over that of nineteen, which represents the proportion of the
+middle finger to the height.</p>
+
+  <div class="figcenter" id="i_185" style="max-width: 320px">
+     <img
+    class="p2"   
+    src="images/i_185.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 64.</p>
+     <p class="p0 sm center smcap">The Facial Angle of a Monkey.</p>
+     <p class="p0 sm center">(Camper.)</p>
+  </div>
+
+<p>Gerdy, who has adopted the law of eight heads, divides the height of
+the body in the following way: the first division comprises the head
+itself; the second extends from the chin to the level of the nipples;
+the third from the nipples to the umbilicus;<span class="pagenum" id="Page_186">[186]</span> the fourth from the
+umbilicus to the symphysis pubis; the fifth from the pubis to the
+middle of the thigh; the sixth from the thigh to the knee; the seventh
+from the knee to the middle of the leg; and, lastly, the eighth, from
+the middle of the leg to the sole of the foot (Fig. <a href="#i_186">65</a>).</p>
+
+  <div class="figcenter" id="i_186" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_186.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 65.</p>
+     <p class="p0 sm center"><span class="smcap">Outline of the Human Body</span> (and proportions).</p>
+  </div>
+
+<p>The face itself can further be subdivided into subordinate parts. The
+classical method of subdivision is to say that the head is the length
+of four noses: one from the top of the head to the top of the forehead
+(hair), one each for the forehead and nose, and one for the part below
+the nose. This is generally, however, incorrect. It is better to divide
+the face into two portions across the equators of the eyeballs; and
+subdivide the lower half into two, for the greater part of the nose
+above, and the lips, mouth, and chin below.</p>
+
+<p>Now, if we submit to experiment the system of the law of eight heads,
+we see that it is accurate only in subjects of great height—for those
+who attain seventy-four inches and over; below seventy-two inches the
+subjects do not measure more than seven and a half, or only seven
+times the height of their head. In fact, the height of the head is a
+quantity which varies very little according to the subject; it is on
+the average, as an absolute measurement, from 8⅔ to 9 inches, and the
+variations which this value may present do not range below 8¼ inches
+or above 9 inches. A subject<span class="pagenum" id="Page_187">[187]</span> who measures eight heads is very tall (9
+× 8 = 72, equal, or superior, to 72 inches); and a subject who only
+measures seven heads is of short stature (8⅔ × 7 = 61, equal, or more
+frequently exceeding, 61 inches).</p>
+
+<p>This difference in the number of heads that the body measures in
+relation to absolute height seems more interesting than the narrow
+theory which would assign strictly the length of eight heads to each
+human figure. This absolute system does not agree with that which
+observation proves correct. Besides, it would be an error to suppose
+that the ancient sculptors would be slaves to such a system of
+proportions, since we find in their works precisely the same variations
+that we do in nature. The <i>Gladiator</i>, it is true, measures eight
+heads; but at the first glance at this <i>chef d’œuvre</i> we have the
+impression of a subject of great stature—of a man tall and spare.
+The <i>Apollo</i> and the <i>Laocoon</i> measure only 7⅔, and the
+<i>Antinous</i> only 7½ heads.</p>
+
+<p>The variations in height are almost solely caused by the greater or
+lesser length of the lower limbs. Whether the subject be tall or short,
+the trunk (with the head and neck) varies comparatively little; but the
+thighs and legs make the differences of length. Regarding the diversity
+that we meet with in this question, we see that Gerdy himself has not
+been exact in indicating the points where the lengths of the head begin
+and terminate which divide the lower limb, the middle of the thigh, and
+the lower part of the knee; those points are badly defined, especially
+as he does not indicate precisely the superior extremity of the thigh.
+But the looseness and contradiction<span class="pagenum" id="Page_188">[188]</span> becomes still more evident when
+we come to seek, according to the various authors, the intersection
+between the fourth and fifth head; that is to say, the middle of the
+body. Without speaking of the singular inconsistency of Vitruvius, who
+places the middle of the body at the level of the navel, we will note
+only this fact, that for the passage from the fourth head to the fifth
+some take the pubis, others some other point.</p>
+
+<p>The centre of height falls lower as the stature of the subject
+is increased. In subjects of small stature the centre of height
+corresponds to the symphysis of the pubis; for those of middle height
+and over, it falls about half an inch below the pubis. But it may be
+situated at a still lower level, and the artists of antiquity have
+frequently placed it much lower. In fact, as Professor Sappey says, the
+taller the stature, the more the centre of the body tends to fall below
+the symphysis, and the figures of heroes and gods are of tall stature.</p>
+
+<p>We will say, then, in conclusion: 1, that the head, compared with the
+height, is shorter as the height increases; 2, that to produce a human
+figure, the absolute dimensions of which would give the impression of
+a subject of short stature, it would be necessary to give it about 7½
+heads, and to cause the centre of the body to fall on the symphysis
+pubis; while to produce a figure to give the impression of tall stature
+it would be necessary to give it 8 heads, and to place the centre of
+the body more or less below the symphysis pubis.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_189">[189]</span></p>
+
+  <div class="figcenter">
+  <img
+    class="p2" 
+    src="images/second_part.jpg"
+    alt="">
+  </div>
+</div>
+
+<hr class="r25">
+
+
+<p class="center sm">MUSCLES AND MOVEMENTS.</p>
+
+
+<hr class="r25">
+
+<h2>CHAPTER XVI.<br>
+<span class="subhed">PECTORAL AND ABDOMINAL MUSCLES.</span></h2>
+
+<div class="blockquot">
+
+<p class="hangingindent">Of <i>muscles</i> in general.—<i>Muscular contraction</i>:
+changes of form; movements produced. Composition of muscles;
+fleshy belly and tendon; aponeurosis. Nomenclature of muscles,
+their classification into long, broad, and short muscles;
+their arrangement: superficial and deep. Muscles of the trunk,
+anterior region.—<i>Great pectoral muscle</i>, its relation
+to the armpit, its action.—<i>The lesser pectoral.</i>—The
+<i>breast</i> and <i>nipple</i>.—The <i>external oblique muscle
+of the abdomen</i>, its fleshy part, its abdominal aponeurosis;
+<i>linea alba</i>.—Groove and space bounded by the prominence
+of the <i>external oblique</i> and <i>rectus</i>.—<i>Internal
+oblique</i> and <i>transversalis</i> muscles.—<i>Rectus
+abdominis</i> muscle, its aponeurotic sheath, its aponeurotic
+intersections.—<i>Linea semilunaris</i>; <i>lineæ
+transversæ</i>.</p>
+</div>
+
+
+<p>The form of the body is produced largely by the muscles. Each muscle
+is formed of a peculiar tissue called <i>muscular tissue</i> or
+<i>muscular fibre</i>, which has the property of changing its form
+and of <i>contracting</i> under the influence of nervous action, in
+most cases controlled by the will. For example, in contracting the
+biceps muscle on the front of the arm, we see that this muscle, which
+in a state of repose is fusiform and long, becomes in action (in
+contraction) short, thick, and rounded; and as it is attached below
+to one of the bones of the forearm, it draws the anterior surface of<span class="pagenum" id="Page_190">[190]</span>
+the forearm towards the anterior surface of the upper arm and produces
+flexion of the elbow-joint. This simple experiment, which is easy to
+repeat at any moment, gives a clear idea of the part which muscles play
+in the animal economy, and of the part that they take in producing the
+external form; for it shows that they are the <i>active agents</i> of
+movements in which the bones are the <i>passive levers</i>, and, at the
+same time, that a muscle in action presents a very different shape from
+that which it has in a state of repose, a change which may be stated
+in a more general manner by saying that in action a muscle becomes
+shorter, thicker, and more prominent.</p>
+
+  <div class="figcenter" id="i_190" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_190.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 66.</p>
+     <p class="p0 sm center"><span class="smcap">Diagram of a Contracted Muscle</span> (Biceps).</p>
+  </div>
+
+<p>In general, besides their <i>fleshy mass</i>, the only part which
+contracts and changes its form, the muscles have extremities more or
+less slender called <i>tendons</i>, formed of a white fibrous tissue,
+which are, as it were, actual cords by which the muscle is attached to
+the bones; during the contraction of muscle these tendons do not change
+in form, but, as with all tight cords when in a state of tension, they
+start up, and become more visible and clearly marked beneath the skin
+(Fig. <a href="#i_190">66</a>).</p>
+
+<p>Each muscle is enveloped by a fibrous membrane<span class="pagenum" id="Page_191">[191]</span> called its
+<i>aponeurosis</i>, which frequently takes the place of a tendon, if
+the muscle is broad and thin, so that in these cases the attachment
+of the muscle, instead of being rounded in the form of a cord, is
+flattened in the form of a membrane, and the term aponeurosis is at
+times applied to these membranous tendons. Membranous tendons in the
+contraction of a muscle give rise to depressions on the surface of the
+body in the regions where they occur superficially.</p>
+
+<p>The muscles are variously named according to various ideas; sometimes
+from the region they occupy (<i>pectoral</i>, <i>gluteal</i>,
+<i>anterior brachial muscles</i>, <i>&amp;c.</i>) or from the direction of
+their fibres (<i>oblique of the abdomen</i>), or from their dimensions
+(<i>gluteus maximus, gluteus medius, and peroneus longus, &amp;c.</i>), or
+again from their form (<i>trapezius, rhomboid, serratus</i>), or from
+their structure (<i>semi-membranosus, semi-tendinosus</i>). Another
+mode of nomenclature, which Chaussier attempted to make general, forms
+the name of a muscle by the association of the names of the bones to
+which it is attached; in this way we get the <i>sterno-cleido-mastoid
+muscle</i>, and most of the muscles of the neck. This nomenclature,
+however, cannot be easily applied to all muscles, for it would make
+some names of an inconvenient length, owing to the complexity of the
+bony attachments.</p>
+
+<p>Before we terminate this rapid sketch it may be useful, with regard
+to plastic anatomy, to point out how the various muscles are classed,
+according to their form and situation. 1st. With regard to their
+form we distinguish the muscles as <i>long</i>, <i>broad</i>, and
+<i>short</i>; the <i>long muscles</i>, consisting in general of a<span class="pagenum" id="Page_192">[192]</span>
+fleshy belly fusiform in shape, and with cord-like tendons, are
+principally distributed among the great segments of the limbs (arm,
+forearm, thigh, leg); the <i>broad muscles</i>, with their fibres
+arranged in broad and thin layers, and with tendons membranous and
+aponeurotic, are almost exclusively found in the trunk (pectorals,
+trapezius, latissimus dorsi, &amp;c.); lastly, the <i>short muscles</i>,
+frequently without tendons, and inserted directly into the bone, are
+found principally at the extremities of the limbs (hand and foot) and
+in the face.</p>
+
+<p>2nd. With regard to their situation we distinguish the muscles as
+<i>superficial</i> and <i>deep</i>. The <i>superficial muscles</i>
+(Fig. <a href="#i_193">67</a>) are those which are entirely visible when the subject is
+stripped of its skin, and of which, accordingly, the fleshy bellies and
+tendons are marked in their principal details on the external form.
+These superficial muscles should be carefully studied here with regard
+to their insertions, forms, and actions. The <i>deep muscles</i>,
+situated beneath the preceding, form fleshy masses, which are shown
+externally by the manner in which they fill up the external depressions
+of the skeleton, and raise up the superficial muscles. It is enough for
+the artist to know the general indications of these muscular masses,
+without studying the insertions and forms of each of the muscles
+composing any given mass.</p>
+
+
+<h3 class="p1">MUSCLES OF THE TRUNK.</h3>
+
+<p>Under this title we will now study the anterior muscles of the trunk
+(<i>pectoral and abdominal</i>), and the muscles of the back and the
+posterior surface of the neck (<i>trapezius</i> and <i>latissimus
+dorsi</i>). The study<span class="pagenum" id="Page_193">[193]</span> of the muscle which covers the lateral wall of
+the chest (<i>serratus magnus</i>) will be taken after that of the
+muscles of the shoulder and armpit.</p>
+
+  <div class="figcenter" id="i_193" style="max-width: 400px">
+     <img
+    class="p2"   
+    src="images/i_193.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 67.</p>
+     <p class="p0 sm"><span class="smcap">General View of the Superficial Muscle</span> (the
+<i>Gladiator</i> of Agasias with the skin removed. Compare with
+Figure <a href="#i_024">4</a>, page 24).</p>
+  </div>
+
+<p><i>Great pectoral muscle.</i>—The great pectoral muscle (<i>pectoralis
+major</i>) forms a large fleshy mass (1, Fig. <a href="#i_194">68</a>) which covers the
+anterior surface of the thorax, on each side of the middle line of the<span class="pagenum" id="Page_194">[194]</span>
+sternum, and extends outwards as far as the upper part of the arm. This
+muscle is attached (1st) to the inner half of the anterior border of
+the clavicle (2, Fig. <a href="#i_194">68</a>); (2nd), to the whole extent of the anterior
+surface of the sternum (3, Fig. <a href="#i_194">68</a>); and (3rd), to the aponeurosis
+of the external oblique muscle of the abdomen. It arises, also, more
+deeply from the cartilages of the true ribs (except<span class="pagenum" id="Page_195">[195]</span> the first) (9,
+9, 9, Fig. <a href="#i_194">68</a>). From these thoracic origins the muscular fibres are
+directed towards the arm; the upper fibres pass obliquely from above
+downwards and outwards; the middle fibres pass transversely outwards,
+and the inferior, obliquely from below upwards. Towards the insertion
+of the muscle these different parts cross over each other in a twisted
+form, so that the upper (clavicular) fibres are placed in front of
+the inferior (sternal) fibres (7, Fig. <a href="#i_194">68</a>), which correspond to the
+anterior margin of the armpit. The muscle is inserted into the outer
+lip of the bicipital groove of the humerus, the clavicular fibres,
+known as the <i>portio attollens</i>, being inserted lower down the arm
+than the external fibres (<i>portio deprimens</i>). The former fibres
+raise the arm upwards, the latter draw it downwards in relation to the
+trunk.</p>
+
+  <div class="figcenter" id="i_194" style="max-width: 400px">
+     <img
+    class="p2"   
+    src="images/i_194.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 68.</p>
+     <p class="p0 sm"><span class="smcap">The Muscles of the Anterior Surface of the Thorax</span>
+(to the right the superficial muscles; to the left the deep
+muscles).—1, the great pectoral muscle;—2, its clavicular
+fibres;—3, its costo-sternal fibres;—4, 5, 6, its origin
+from the aponeurosis of the abdomen;—7, its external portion
+formed by the superposition of the preceding fibres (9, bundles
+of fibres arising from the cartilages of the ribs; 10, the
+pectoralis minor);—11, the subclavius;—12, the deltoid;—14,
+the digitations of the serratus magnus;—15, the digitations of
+the external oblique of the abdomen;—16, anterior border of
+the latissimus dorsi, and (17) tendon of the same;—18, teres
+major muscle;—19, the subscapularis;—20, the long head of the
+triceps brachialis; 21, the humeral extremity of the deltoid;
+22, 22, the sterno-cleido-mastoid;—23, the sterno-hyoid;—24,
+the trapezius muscle.</p>
+  </div>
+
+<p>When the arm is hanging beside the trunk the great pectoral muscle
+presents a four-sided square, in which we can distinguish four borders:
+one supero-external (in contact with the anterior border of the
+deltoid, 12, Fig. <a href="#i_194">68</a>), another superior, in the line of the clavicle;
+the third, internal or sternal, curved with its convexity inwards; and
+the fourth, infero-external or axillary (forming the anterior boundary
+of the armpit). But when the arm is horizontal, and especially when it
+is raised above the horizontal (Fig. <a href="#i_197">70</a>), the figure of the muscle is
+represented by a triangle with the base inwards, as the clavicular and
+supero-external borders then come into line with one another.</p>
+
+<p>The action of the great pectoral muscle is essentially to draw the
+arm to the trunk; its<span class="pagenum" id="Page_196">[196]</span> shape becomes prominent when we carry the arms
+forward and bring them near each other, as in the attitude of prayer.
+It also becomes well marked in climbing, for then the muscle takes its
+fixed point at the humerus and draws the trunk towards it. Acting in
+a similar manner upon the thorax, with the humerus as a fixed point,
+this muscle elevates the ribs, and consequently expands the thorax in
+respiration. Thus we see that the muscle contracts when the inspiratory
+muscular powers are brought into play as in movements like struggling,
+anguish, or agony.</p>
+
+  <div class="figcenter" id="i_196" style="max-width: 250px">
+     <img
+    class="p2"   
+    src="images/i_196.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 69.</p>
+     <p class="p0 sm center smcap">Outline of the Female Breast.</p>
+  </div>
+
+<p><i>The breast and nipple.</i>—On the surface of the great pectoral
+muscle is placed the breast in the female. In the male only the nipple
+and surrounding <i>areola</i> are found, usually occupying a position
+at the level of the space between the fourth and fifth ribs on each
+side. The form of the breast varies in the female with age. In a
+young woman it is normally round and firm, with its lower aspect more
+rounded than its upper surface, which is slightly flatter (in the erect
+position) (Fig. <a href="#i_196">69</a>).</p>
+
+  <div class="figcenter" id="i_197" style="max-width: 363px">
+     <img
+    class="p2"   
+    src="images/i_197.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 70.</p>
+     <p class="p0 sm"><span class="smcap">The Muscles of the Anterior Wall of the Trunk.</span>—1,
+2, 3, the great pectoral;—4, 4, the external oblique of the
+abdomen;—5, 5, the serratus magnus;—6, 6, the anterior border
+of the latissimus dorsi;—7, 8, the inferior portion of the
+sternum;—9, the aponeurosis of the external oblique;—10,
+linea alba;—11, umbilicus;—12, 12, 12, the tendinous
+intersections of the rectus abdominis;—13, the inguinal
+ring;—14, the pyramidalis of the abdomen;—15, the external
+border of the rectus abdominis;—16, the sterno-hyoid;—17,
+the omo-hyoid;—18, sterno-cleido-mastoid;—19, the
+trapezius;—20, the deltoid;—21, the biceps brachialis;—22,
+the pectineus;—23, the sartorius;—24, the rectus femoris;—25,
+the tensor of the <i>fascia lata</i>;—26, the adductors.</p>
+  </div>
+
+<p>The great pectoral muscle conceals under its middle third a smaller
+muscle, the <i>lesser pectoral</i> (10, Fig. <a href="#i_197">68</a>), which, arising from
+the third, fourth, and<span class="pagenum" id="Page_198">[198]</span> fifth ribs, is directed upwards and outwards,
+to be attached to the coracoid process of the scapula. This muscle
+serves to move the scapula by drawing its upper part downwards and
+forwards. Its outer border becomes obvious when the arm is raised above
+the head, along the axillary border of the great pectoral muscle.</p>
+
+<p><i>The external oblique muscle of the abdomen.</i>—The external
+oblique muscle of the abdomen (Figs. <a href="#i_194">68</a> and <a href="#i_197">70</a>) forms a large sheet
+half fleshy, half aponeurotic, which covers the lateral and anterior
+surfaces of the abdomen. The fleshy portion, which forms the outer half
+of the muscle, is attached to the external surfaces of the lower eight
+ribs, from which it arises by angular slips or digitations, interlacing
+with those of the serratus magnus and latissimus dorsi muscles (15,
+Fig. <a href="#i_194">68</a>, and Fig. <a href="#i_217">74</a>). From these costal origins the fibres are carried
+forwards and downwards; the posterior fibres pass vertically downwards
+to be attached to the iliac crest (Fig. <a href="#i_217">74</a>); the others are directed
+obliquely downwards and forwards, to give origin to a broad membranous
+tendon (9, Fig. <a href="#i_197">70</a>) called the <i>aponeurosis of the external oblique
+muscle</i>. The fibres of this aponeurosis, continuing in the original
+direction of the muscular fibres, pass in front of the rectus muscle
+of the abdomen (12 and 15, Fig. <a href="#i_197">70</a>), where, joining the subjacent
+aponeuroses of the internal oblique and transversalis muscles, and
+interlacing with the aponeurotic fibres of the opposite side, it forms
+a long median raphé, called the <i>linea alba of the abdomen</i>,
+proceeding<span class="pagenum" id="Page_199">[199]</span> from the xiphoid cartilage to the symphysis pubis (10, Fig.
+<a href="#i_197">70</a>).</p>
+
+<p>It is important, with regard to external form, to define the direction
+of the line at which the aponeurotic fibres of the external oblique
+succeed to the fleshy fibres (Fig. <a href="#i_197">70</a>). This line descends at first
+vertically from its origin at the inferior angle of the great pectoral
+muscle, but its lower part inclines abruptly outwards (4, Fig. <a href="#i_197">70</a>),
+towards the anterior superior iliac spine, describing a curve with
+its convexity downwards and inwards. This line marks the prominence
+of the anterior or internal border of the muscular fibres; and as,
+on the other hand, the rectus abdominis muscle forms, by its outer
+border, another curved line (<i>linea semilunaris</i>), which is at
+first vertical but inclines inwards below (15, Fig. <a href="#i_197">70</a>), it follows
+that this part of the anterior surface of the abdomen is traversed by
+a narrow vertical groove which opens out below into a large triangular
+space. This triangular space, bounded above and on the outer side by
+the external oblique muscle, and on the inner side by the semi-lunar
+line of the rectus, is limited below by the fold of the groin, or
+<i>Poupart’s ligament</i>, the line at which the aponeurosis of the
+external oblique becomes attached to the fascia lata of the thigh (page
+111). In the male this part of the aponeurosis of the external oblique
+is perforated just above the inner end of Poupart’s ligament (13, Fig.
+<a href="#i_197">70</a>) by the spermatic cord, which passes obliquely downwards and inwards
+in the inner part of the groin.</p>
+
+  <div class="figcenter" id="i_200" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_200.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 71.</p>
+     <p class="p0 sm"><span class="smcap">The Muscles of the Abdomen</span> (the superficial on the
+right side, the deep on the left).—1, the external oblique;—2,
+2, the serratus magnus;—3, 3, the aponeurosis of the external
+oblique;—4, the umbilicus;—5, 6, the linea alba;—7, the
+crural arch or Poupart’s ligament;—8, the inguinal ring;—9,
+pectoralis major;—10, latissimus dorsi;—11, 11, the rectus
+abdominis;—13, the anterior portion of its sheath;—14, the
+pyramidalis;—15, 15, the internal oblique of the abdomen;—16,
+the inferior portion of the aponeurosis of the external oblique
+turned downwards;—18, the upper part of the thigh covered by
+its aponeurotic envelope;—19, a section of the external oblique
+of the abdomen.</p>
+  </div>
+
+<p>The external oblique muscle draws the ribs downwards<span class="pagenum" id="Page_200">[200]</span> and forwards. If
+the two muscles of that name (that of the right and that of the left
+side) contract at the same time they bend the body forward; but when
+one muscle only—<i>e.g.</i>, that of the right side—contracts it
+imparts to the trunk a movement of rotation to the left or opposite
+side.<span class="pagenum" id="Page_201">[201]</span> Generally speaking, whenever we make any great effort the
+oblique muscles of the abdomen contract, and their prominences,
+especially the costal digitations<span class="pagenum" id="Page_202">[202]</span> and the anterior borders of the
+muscles, become clearly marked.</p>
+
+  <div class="figcenter" id="i_201" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_201.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 72.</p>
+     <p class="p0 sm"><span class="smcap">The Muscles of the Back.</span>—1, trapezius;—2, its
+vertebral origin;—3, acromion process;—4, Latissimus
+dorsi;—5, deltoid;—6, infraspinatus;—7, obliquus
+externus;—8, gluteus medius;—9, gluteus maximus;—10,
+levator anguli scapulæ;—11, rhomboid minor;—12, rhomboid
+major;—13, splenius;—14, transversalis cervicis;—15,
+vertebral aponeurosis;—16, serratus posticus inferior;—17,
+supraspinatus;—18, infraspinatus;—19, teres minor;—20,
+teres major;—21, triceps;—22, serratus magnus;—23, obliquus
+internus.</p>
+  </div>
+
+<p>The external oblique muscle covers two other muscular layers, which
+are, passing from without inwards, the <i>internal oblique</i> (15,
+Fig. <a href="#i_200">71</a>) and <i>transversalis</i> muscles. The internal oblique muscle
+is formed by fibres which arise from the fascia of the loin, the crest
+of the ilium, and Poupart’s ligament. They radiate forwards and for the
+most part upwards (Fig. <a href="#i_200">71</a>) to become attached, the superior fibres to
+the lower six ribs, while the middle and inferior fibres are continued
+in front as an aponeurosis, or broad flat tendon. The aponeurosis soon
+becomes united, partly, with that of the external oblique and that
+of the transversalis beneath. This aponeurosis splits to enclose the
+rectus abdominis muscle and constitute the <i>sheath of the rectus</i>.
+The <i>transversalis</i> muscle is formed by fibres directed
+horizontally, and it terminates in front in an aponeurosis which passes
+for the most part behind the <i>rectus abdominis</i>, to blend with the
+aponeurosis of the internal oblique muscle and assist in the formation
+of the sheath of the rectus abdominis.</p>
+
+<p>The <i>rectus abdominis</i> (11, 11, Fig. <a href="#i_200">71</a>).—This muscle forms a
+long, broad, fleshy band on each side of the <i>linea alba</i>, which
+occupies the middle line of the abdomen. Extending from the epigastric
+pit to the pubis, it is attached above at its base, which is its widest
+part, to the cartilages of the filth, sixth, and seventh ribs, and to
+the ensiform cartilage, and below, at its apex, or narrowest part,
+by a double tendon to the crest and spine of the pubis. The muscle
+presents, with regard to form,<span class="pagenum" id="Page_203">[203]</span> several remarkable peculiarities. 1st.
+It is enclosed in a fibrous sheath, formed in front by the aponeuroses
+of the external and internal oblique muscles (16, Fig. <a href="#i_200">71</a>), and behind
+by the aponeuroses of the internal oblique and transversalis; so that
+in the subject stripped of its skin its shape is half concealed by the
+aponeurotic lamina which passes in front of it (Fig. <a href="#i_197">70</a> and the right
+half of Fig. <a href="#i_200">71</a>). 2nd. It is not formed of fleshy fibres proceeding
+without interruption from the costal cartilages to the pubis, but it
+is crossed by aponeurotic intersections (Figs. <a href="#i_197">70</a>, <a href="#i_200">71</a>), the <i>lineæ
+transversæ</i>, at the level of which the fleshy fibres are replaced
+by short tendinous fibres. These aponeurotic intersections are
+usually three in number, the most inferior being placed at the level
+of the umbilicus (4, Fig. <a href="#i_200">71</a>), the other two higher up—one at the
+level of the ninth rib, the other at the level of the seventh. These
+intersections adhere to the anterior wall of the sheath of the muscle,
+and as the muscle is thinner at their level each line is marked on
+the surface by a transverse groove. 3rd. The portion of the muscle
+below the level of the umbilicus does not present any aponeurotic
+intersection, but it rapidly diminishes in breadth from the umbilicus
+to the pubis, so that the outer border of the muscle slopes from above
+downwards and inwards. To this arrangement is due the fact, upon which
+we have already dwelt (page 199), that the narrow groove bounded by the
+external oblique and the rectus muscles spreads out below the umbilicus
+into a broad, triangular surface, which is bounded below by the fold of
+the groin.</p>
+
+<p><span class="pagenum" id="Page_204">[204]</span></p>
+
+<p>The rectus muscle flexes the trunk; that is, it depresses the thorax
+and brings it nearer the pubis—a movement which it accomplishes by the
+flexion of the vertebral column.</p>
+
+<p>The lower part of the rectus muscle is covered by the
+<i>pyramidalis</i> muscle (14, Fig. <a href="#i_200">71</a>), of which the contour does
+not show beneath the skin in the supra-pubic region, as the skin here
+is always padded by a cushion of fat. This pyramidalis muscle, which
+is only pointed out here in order that it may be remembered, forms on
+each side of the middle line a small fleshy triangle, of which the base
+is attached to the pubis, and the apex forms a short tendon which is
+inserted into the linea alba, the median fibrous raphé resulting from
+the interlacing of the aponeuroses of the oblique and transversalis
+muscles of the abdominal wall.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_205">[205]</span></p>
+
+<h2>CHAPTER XVII.<br>
+<span class="subhed">MUSCLES OF THE BACK.</span></h2></div>
+
+<div class="blockquot">
+
+<p class="hangingindent"><i>Trapezius</i>, attachments and surface form.—<i>Latissimus
+dorsi.</i>—<i>Deep muscles</i> visible in relation to the
+trapezius and latissimus dorsi—1, lateral region of neck
+(<i>splenius</i> and <i>complexus</i> muscles); 2, region of
+the scapula (<i>rhomboid</i>, <i>infraspinatus</i>, <i>teres
+major</i> and <i>teres minor</i> muscles).—Deep muscles which
+are wholly concealed: <i>erector spinæ</i>, etc.</p>
+</div>
+
+
+<p>The most superficial muscles of the back are the trapezius and the
+latissimus dorsi. They form two broad muscular sheets which cover over
+the whole of the back and the posterior part of the neck, and extend
+also to the shoulder and arm.</p>
+
+<p><i>Trapezius muscle.</i>—The <i>trapezius</i> muscle has the following
+attachments. Its origin is from the middle line of the back, from the
+inner third of the superior curved line of the occipital bone (13,
+Fig. <a href="#i_207">73</a>), the fibrous band of the <i>ligamentum nuchæ</i> between the
+occipital protuberance and the spinous process of the seventh cervical
+vertebra, and from the spinous processes of the seventh cervical and
+of all the thoracic vertebræ. From these origins the muscular fibres
+are carried outward and converge towards the shoulder, the intermediate
+fibres passing transversely, the superior obliquely downwards (9, Fig.
+<a href="#i_217">74</a>), and the inferior fibres obliquely upwards. The muscle is inserted
+into the shoulder girdle, to the superior border of the spine of the
+scapula (Fig. <a href="#i_207">73</a>), the inner edge of the acromion process, and the
+outer third of the<span class="pagenum" id="Page_206">[206]</span> posterior border of the clavicle (19, Fig. <a href="#i_197">70</a>;
+7–13, Fig. <a href="#i_207">73</a>).</p>
+
+<p>With regard to external form the trapezius muscle presents this
+remarkable fact, that in certain regions the muscular fibres are
+replaced by aponeurotic fibres or tendons, so that in these regions the
+muscle is thinner and in contraction shows slightly depressed surfaces.
+These regions are three in number: 1. At the lower part of the neck
+and the upper part of the back (10, Fig. <a href="#i_207">73</a>), opposite the level of
+the seventh cervical spine, the fibres of origin of the muscle are
+aponeurotic, and form with those of the opposite side a lozenge-shaped
+or elliptical surface with its long diameter vertical, in the centre of
+which the spinous processes of the sixth and seventh cervical and first
+thoracic vertebræ form more or less well-marked projections. 2. At the
+lower part of the back, at the level of the last thoracic vertebræ,
+the fibres of origin of the trapezius are also aponeurotic, in a small
+triangular space; and in the living model, when the trapezius is
+strongly contracted, its lower angle seems hollowed out, because at
+that level the muscular fibres are wanting, and in consequence do not
+swell up when the muscle is in action. 3. At the level of the root of
+the spine of the scapula, the inferior fibres of the trapezius form
+at their insertion a small triangular aponeurosis which glides on the
+bone, and gives rise to a distinct depression at that spot during the
+contraction of the muscle.</p>
+
+  <div class="figcenter" id="i_207" style="max-width: 327px">
+     <img
+    class="p2"   
+    src="images/i_207.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 73.</p>
+     <p class="p0 sm"><span class="smcap">The Superficial Muscles of the Back.</span>—1, The
+lumbo-sacral aponeurosis;—2, the latissimus dorsi;—3, its
+iliac fasciculus;—4, the space which separates it from the
+external oblique;—5, the upper portion of the latissimus
+dorsi;—6, 6, the teres major muscle;—7, the lower portion
+of the trapezius, with its aponeurotic portion (8) on a level
+with the spine of the scapula;—9, the central portion of
+the trapezius, with its aponeurosis (10);—11, 12, 13, the
+upper portion of the trapezius;—15, the occipito-frontalis
+muscle;—16, the sterno-cleido-mastoid;—17, the splenius
+capitis;—18, the deltoid;—19, the infraspinatus;—20, the
+teres minor;—21, 21, the external head, and 22, 22, internal
+head of the triceps brachialis;—23, the posterior portion
+of the external oblique of the abdomen;—24, 24, the gluteus
+maximus.</p>
+  </div>
+
+<p><i>Action of the trapezius.</i>—When the shoulder is strongly drawn
+backwards the whole of the<span class="pagenum" id="Page_208">[208]</span> trapezius contracts, and in this case it
+is the middle portion, of which the fibres are directed horizontally,
+which shows most prominently beneath the skin. More frequently,
+however, different parts of the muscle contract separately; thus the
+superior fibres act, either by taking the shoulder as a fixed point,
+and bending the head to the corresponding side (as when the face
+is slightly turned to the opposite side), or by taking their fixed
+point at the occipital and the cervical origin, and thus raising and
+supporting the scapula, as when a burden is carried on the shoulder.
+Under those circumstances the cervical border of the trapezius, that
+which proceeds from the occipital bone to the clavicle (Fig. <a href="#i_217">74</a>),
+becomes prominent in a line nearly parallel to that of the outer border
+of the sterno-cleido-mastoid (26, Fig. <a href="#i_217">74</a>); and between these two
+prominent lines appears a groove (the <i>posterior triangle</i> of the
+neck), to which we will return in dealing with the deep muscles of this
+region. Lastly, if the inferior fibres of the trapezius contract alone,
+they draw the shoulder downwards, and thus we see them become prominent
+whenever the model causes a dragging with his upper limbs from above
+downward, <i>e.g.</i>, in the case of a bell-ringer who pulls violently
+and with all his weight on a rope.</p>
+
+<p>The two trapezius muscles (right and left) form together (Fig. <a href="#i_207">73</a>) a
+rhomboidal figure with its apex below, which resembles the contour of
+a monk’s hood. Hence the trapezius has been called by anatomists and
+artists the <i>cucullary muscle</i> (<i>cucullus</i>, a hood).</p>
+
+<p><span class="pagenum" id="Page_209">[209]</span></p>
+
+<p><i>Latissimus dorsi muscle</i> (1, 2, 3, 5, Fig. <a href="#i_207">73</a>).—This forms a
+large, somewhat triangular muscular sheet extending from the region
+of the loins to the upper part of the arm. It arises by means of a
+broad triangular aponeurosis (<i>vertebral aponeurosis</i>, 1, Fig.
+<a href="#i_207">73</a>) from the spinous processes of the lower six thoracic vertebræ,
+from the spinous processes of the lumbar and sacral vertebræ and the
+posterior third of the crest of the ilium (3, Fig. <a href="#i_207">73</a>); the muscular
+fibres converge from this origin towards the armpit, and the muscle
+obtains additional origins at its borders. At the outer border of the
+muscle, three or four fleshy bands join it which arise from the outer
+surfaces of the last three or four ribs by slips which interdigitate
+with the fibres of the external oblique muscle of the abdomen (4, 4,
+Fig. <a href="#i_217">74</a>). At its upper border, as it crosses the inferior angle of the
+scapula, the muscle receives a narrow slip of origin from this part of
+the shoulder-blade. From these origins the muscular fibres are directed
+upwards and outwards, and converge so as to form a fleshy layer (5,
+Fig. <a href="#i_207">73</a>) which, passing over the inferior angle of the scapula and
+along its axillary border, winds round the <i>teres major muscle</i>
+(see later), and over the posterior wall of the armpit to reach the
+upper part of the shaft of the humerus, in which it is inserted by a
+broad tendon, attached to the floor of the bicipital groove of the
+humerus (page 61).</p>
+
+<p>This muscle acts first of all like the lower part of the trapezius,
+but with more energy. It, further, not only depresses the scapula, but
+also acts on the humerus. It is the contraction of the latissimus<span class="pagenum" id="Page_210">[210]</span>
+dorsi which enables us to bring the arm with force to the side,
+carrying the upper limb slightly backwards, so that if the contraction
+is carried very far the arms become crossed behind the back. Indeed,
+the latissimus dorsi may be called the swimmer’s or golfer’s muscle.
+It draws the humerus backwards behind the trunk, and at the same time
+rotates the arm-bone and the whole limb inwards. The prominence formed
+by the outer border of the latissimus dorsi during contraction (Fig.
+<a href="#i_217">74</a>) is principally shown when the muscle accomplishes a powerful
+effort, such as dragging, or pulling from above downwards, as in
+pulling on a rope hanging vertically, or in hanging by the arms from a
+horizontal bar. If in this situation—in the exercise of the trapeze,
+for example—the model raises himself, and brings the trunk near the
+bar, the latissimi dorsi muscles become very prominent, for then they
+take their fixed points at the arms, and act on the trunk by carrying
+it upwards and forwards.</p>
+
+<p>Among the numerous deep muscles of the back there are not any which are
+visible on the surface throughout their entire extent, but there are
+many which appear in part in the spaces which limit the borders of the
+trapezius, latissimus dorsi, and superficial muscles of the shoulder
+and neck. These spaces are three in number, one at the side of the
+neck, one at the level of the lower half of the scapula, and a third
+over the iliac crest.</p>
+
+<p>The <i>posterior triangle</i> is the name given to the space on the
+lateral surface of the neck, bounded (Figs. <a href="#i_207">73</a> and <a href="#i_217">74</a>) behind by the
+supero-anterior border of the trapezius, and in front by the posterior<span class="pagenum" id="Page_211">[211]</span>
+border of the sterno-cleido-mastoid. This space forms a long and
+superficial groove, extending from the occipital region to the middle
+of the clavicle. It has a lower part (25, Fig. <a href="#i_217">74</a>), covered over by the
+<i>platysma myoides</i> muscle of the neck (to which we will return
+later), and a superior part, in which parts of one or two powerful
+muscles of the neck are found. 1st. The muscular fibres which we see
+(17, Fig. <a href="#i_207">73</a>) directed obliquely from below upwards and outwards
+towards the mastoid process belong to the <i>splenius capitis</i>
+muscle, which arises from the spinous processes of the last cervical
+and upper four or five thoracic vertebræ, and ascends obliquely
+outwards to be attached to the mastoid process of the temporal bone
+beneath the sterno-cleido-mastoid (16, Fig. <a href="#i_207">73</a>). 2nd. A small fleshy
+triangle, which may appear above the splenius, at the apex of the
+posterior triangle, corresponds to a part of a powerful muscle of the
+neck, called the <i>complexus</i>, which may or may not be completely
+concealed by the trapezius muscle. It is always responsible for the
+surface form of the neck, and, along with the other deep muscles,
+appears as a prominent ridge on each side of the groove formed by the
+edge of the ligamentum nuchæ.</p>
+
+<p>The space situated in the back at the level of the lower part of the
+scapula is triangular in form (Figs. <a href="#i_207">73</a> and <a href="#i_217">74</a>). When the arm is
+hanging beside the trunk the borders of the space are seen to be as
+follows: Externally, the vertebral border of the scapula; above and
+internally, the lower edge of the trapezius; and below, the upper<span class="pagenum" id="Page_212">[212]</span> edge
+of the latissimus dorsi. In the floor of the space the greater rhomboid
+muscle is seen; while external to the triangle are the prominences
+of the muscles covering the lower part of the dorsal surface of the
+scapula, <i>the infraspinatus</i>, <i>teres minor</i>, and <i>teres
+major</i> muscles.</p>
+
+<p>The <i>greater rhomboid muscle</i> (rhomboideus major) arises from
+the spinous processes of the seventh cervical and upper four or five
+thoracic vertebræ; its fibres are directed obliquely downwards and
+outwards, to be inserted into the vertebral border of the scapula. It
+is only the lower fibres which become superficial, behind the vertebral
+border of the scapula.</p>
+
+<p>The <i>infraspinatus muscle</i> (19, Fig. <a href="#i_207">73</a>) rises from the
+infra-spinous fossa of the scapula. From this origin its fibres ascend
+and, converging beneath the deltoid (Fig. <a href="#i_217">74</a>), are inserted by a short
+tendon into the great tuberosity of the humerus.</p>
+
+<p>The <i>teres minor muscle</i> (20, Fig. <a href="#i_207">73</a>) rises from the upper part
+of the thick border of the infra-spinous fossa on the axillary border
+of the scapula, and ascends along the edge of the infraspinatus and
+beneath the deltoid, to be inserted into the lowest of three facets on
+the great tuberosity of the humerus.</p>
+
+<p>The <i>teres major</i> (6, Fig. <a href="#i_207">73</a>, and 8, Fig. <a href="#i_217">74</a>) arises from the
+lower part of the broad axillary border of the infra-spinous fossa;
+it extends upwards and outwards like the preceding muscles, but it
+soon leaves the teres minor (5, Fig. <a href="#i_225">75</a>). Instead of remaining at the
+posterior part of the shoulder it passes beneath the deltoid, and
+accompanies<span class="pagenum" id="Page_213">[213]</span> the latissimus dorsi muscle (Figs. <a href="#i_057">17</a>, <a href="#i_060">18</a>; Fig. <a href="#i_194">68</a>) to the
+front of the long head of the triceps, and is finally inserted into the
+inner lip of the bicipital groove of the humerus. The long head of the
+triceps is found, therefore, passing between the teres minor, behind,
+and the upper part of the teres major, in front (Fig. <a href="#i_207">73</a>, between 20
+and 6).</p>
+
+<p>These muscles become more visible and prominent when the arm is raised
+and arrives at the horizontal position (see the right side of Fig.
+<a href="#i_207">73</a>). The space between the edge of the trapezius and the border of the
+scapular spine above, and the latissimus dorsi below, becomes much
+lengthened from within outwards, and the deltoid leaves uncovered
+a greater extent of the infraspinatus, teres major and teres minor
+muscles; at the same time the scapula, by the elevation of the arm
+(page 64), being moved so that its inferior angle is drawn away from
+the vertebral column, a greater part of the rhomboid muscle becomes
+apparent between the outer border of the trapezius and the upper border
+of the latissimus dorsi.</p>
+
+<p>Although the other deep muscles of the back are not visible on the
+subject stripped of its skin, we must not leave the region without
+giving a few of the names of the powerful fleshy masses which occupy
+the lumbar region, on each side of the spinous processes, and form two
+powerful muscular columns, causing a prominence beneath the aponeurosis
+of the latissimus dorsi (Fig. <a href="#i_207">73</a>). This mass is formed by muscles in
+the loin which are closely blended together<span class="pagenum" id="Page_214">[214]</span> below, and constitute the
+<i>erector spinæ</i>. At the lower level of the thorax it separates
+into an external muscle called the <i>ilio-costalis</i>, which is
+attached by a series of tendons to the angles of the ribs, and an
+internal muscle called the <i>longissimus dorsi</i>, which, by a series
+of tendons, is attached to the ribs and to the transverse processes of
+the thoracic vertebræ. These muscles are continued through the upper
+part of the back and the neck by means of smaller slips which need not
+be particularised. The action of the erector spinæ and its several
+parts is to straighten the trunk, and maintain it when a burden is
+borne on the shoulders or back. It is for this reason that their common
+mass in the lower part of the back is so developed in men who usually
+carry heavy loads on the shoulders, and forms that powerful muscular
+mass of the loins, of which the prominence is visible beneath the skin
+and the aponeurosis of the latissimus dorsi (1, Fig. <a href="#i_207">73</a>). In the neck,
+as already stated, the <i>complexus</i> is the most important of the
+deep muscles in giving rise to the form and contour of this region.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_215">[215]</span></p>
+
+<h2>CHAPTER XVIII.<br>
+<span class="subhed">MUSCLES OF THE SHOULDER AND ARMPIT.</span></h2></div>
+
+<div class="blockquot">
+
+<p class="hangingindent">The <i>deltoid</i>: its <i>form</i>, <i>thickness</i>,
+<i>actions</i>.—Muscular form of the shoulder as a
+whole.—The deeper muscles (<i>supraspinatus</i> and
+<i>subscapularis</i>).—<i>Serratus magnus</i> muscle: its
+relation to the armpit, its costal digitations; its action
+in movements of the arm.—Forms of the region of the armpit;
+prominence of the <i>coraco-brachialis</i> muscle; relations of
+the <i>biceps</i> and <i>triceps</i> to the armpit.</p>
+</div>
+
+
+<p>The upper and outer part of the prominence of the shoulder is formed
+by a single powerful muscle, called the <i>deltoid</i>. Beneath this
+are several deep muscles which fill up the fossæ of the scapula
+(<i>supraspinatus</i>, <i>infraspinatus</i>, and <i>subscapularis</i>).
+But when the arm is raised and maintained in the horizontal position,
+the surface below the root of the arm dips into a cavity or pit,
+corresponding to the external prominence of the shoulder; this cavity,
+called the <i>armpit</i>, or <i>axilla</i>, has for a roof the skeleton
+of the shoulder covered by the deltoid, and for its walls—in front,
+the pectoral muscles, which adjoin the anterior border of the deltoid,
+and behind, the subscapularis and the latissimus dorsi, separated
+from the posterior border of the deltoid by the teres major muscle.
+On the inner side is a muscle applied to the wall of the thorax,
+the <i>serratus magnus</i>, and on the outer side is the humerus,
+covered by the <i>biceps</i> and <i>coraco-brachialis</i> muscles. Of
+the muscles which we have<span class="pagenum" id="Page_216">[216]</span> named, some have already been studied in
+relation to the muscular structure of the trunk (great pectoral and
+latissimus dorsi); of the others, we will study the <i>deltoid</i> and
+<i>serratus magnus</i>, in relation to the region of the shoulder and
+axilla.</p>
+
+<p><i>Deltoid muscle.</i>—This muscle is so called because it resembles
+the Greek letter delta, and is triangular in form; it is short, broad,
+thick, and shaped like half a cone to clasp the shoulder-joint. It
+arises above from the outer third of the anterior border of the
+clavicle (12, Fig. <a href="#i_194">68</a>), from the acromio-clavicular articulation, from
+the convex border of the acromion, and from the entire extent of the
+posterior border of the spine of the scapula (18, Fig. <a href="#i_207">73</a>). From this
+origin its fibres are directed downwards, the middle fibres vertically,
+the anterior or clavicular fibres downwards and backwards, and the
+posterior fibres obliquely forwards, to be inserted into the external
+surface of the humerus on a rough <img src="images/thick_v.jpg" alt=""
+style="height:1em;  padding:0 0em 0 0em;">-shaped groove, called the deltoid impression (page 68).</p>
+
+  <div class="figcenter" id="i_217" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_217.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 74.</p>
+     <p class="p0 sm"><span class="smcap">The Superficial Muscles of the Shoulder and the Lateral
+Portion of the Trunk.</span>—1, the latissimus dorsi;—2, the
+lumbo-sacral aponeurosis;—3, 4, 4, the iliac and costal
+origins of the latissimus dorsi;—5, 6, 7, the upper portion
+of the latissimus dorsi;—8, the teres major;—9, 10, 11, the
+trapezius;—12, the infraspinatus;—13, the teres minor;—14,
+15, 16, the external oblique of the abdomen;—17, 18, the
+anterior and interior border of the same muscle;—19, its
+inferior internal angle rounded (see page 199);—20, 20,
+serratus magnus;—21, the pectoralis major;—22, the gluteus
+maximus;—23, the tensor of the <i>fascia lata</i>;—24,
+the deltoid;—25, the platysma myoides;—26, the
+sterno-cleido-mastoid.</p>
+  </div>
+
+<p>This muscle is very thick, and is intersected by a vertical series of
+strong fibrous bands or septa, which may be seen as depressions beneath
+the skin in the contracted muscle. The action of the deltoid is to
+elevate the arm, separating it from the trunk and supporting it in the
+horizontal position; but while the middle fibres raise the arm directly
+outwards, the anterior fibres elevate it and carry it forwards, and the
+posterior fibres carry it backwards. It is necessary to remark that
+this muscle is never at right angles to the lever which it moves, but
+it always acts obliquely<span class="pagenum" id="Page_218">[218]</span> on the humerus. Hence, although very thick,
+the deltoid cannot act with great power; therefore the horizontal
+position of the arm produced by the action of the muscle is one which
+requires great effort and quickly produces fatigue. In order to
+understand the unfavourable arrangement of the deltoid with relation to
+its humeral lever, it is sufficient to compare it with that which the
+biceps presents relative to the forearm, and to see that the biceps,
+which acts obliquely on the radius, becomes perpendicular to that bone
+in proportion as flexion is carried on in the arm; and when the elbow
+forms a right angle, the biceps muscle is found in the most favourable
+condition to act with all possible force. In other words, the greatest
+<i>momentum</i> of a muscle occurs when it is perpendicular to its
+lever; the deltoid muscle, therefore, does not possess much momentum.</p>
+
+<p>In pointing out the relations which the three borders of the deltoid
+present, we summarise the various details of the muscular contour of
+the shoulder:—1st. The <i>superior border</i> of the deltoid, by its
+origin from the anterior border of the clavicle and the posterior
+border of the spine of the scapula, repeats the insertions of the
+trapezius, which is attached to the opposite lip and border of the
+same bones (Fig. <a href="#i_217">74</a>). The clavicle, acromion, and spine of the scapula
+form a species of bony intersection between the trapezius and deltoid,
+and when the muscles are contracted produce a deep groove between the
+insertion of the trapezius and the origin of the deltoid. In animals
+which have no clavicle, and in which the spine of the scapula is not
+well developed, the fibres<span class="pagenum" id="Page_219">[219]</span> of the deltoid and trapezius are directly
+continuous. We observe an arrangement of this nature in the horse.
+2nd. The <i>anterior border</i> of the deltoid is separated from
+the corresponding border of the great pectoral muscle by a linear
+interval, very narrow below, but a little broader above, where it
+forms a small triangle, of which the base corresponds to the middle of
+the clavicle (Fig. <a href="#i_197">70</a>). This interval, which becomes visible during
+the contraction of the two muscles when we endeavour to raise the arm
+upwards and forwards while it is held behind, as in the act of drawing
+a load, gives passage to a vein called the <i>cephalic</i>, and under
+such circumstances this vein becomes prominent and swollen. 3rd. The
+<i>posterior border</i> of the deltoid forms one of the sides of the
+triangular space which we have studied in the region of the back, at
+the level of the infra-spinous fossa (Figs. <a href="#i_207">73</a> and <a href="#i_217">74</a>); and, under its
+posterior border, pass successively on the one hand the infraspinatus
+and teres minor muscles, which pass directly beneath the deltoid, and
+on the other the teres major and latissimus dorsi muscles, which pass
+more deeply, separated from the deltoid by the long head of the triceps
+muscle (Fig. <a href="#i_225">75</a>).</p>
+
+<p>Two muscles of the shoulder remain to be mentioned which are not
+visible on the model, but must at least be named in order to explain
+how the fossæ of the shoulder-blade are filled up. These are:—1st.
+The <i>supraspinatus</i> muscle (11, Fig. <a href="#i_225">75</a>), which occupies the
+supra-spinous fossa of the scapula, passes beneath the coraco-acromial
+arch, and is inserted into the uppermost facet of the great tuberosity
+of the humerus. 2nd. The <i>infraspinatus</i> muscle occupies<span class="pagenum" id="Page_220">[220]</span> the
+infra-spinous fossa, and is partially concealed by the latissimus
+dorsi, trapezius, and deltoid. It is also bound down on the back of
+the scapula by a strong membrane derived from the deep fascia. It is
+inserted below the supraspinatus into the back of the great tuberosity
+of the humerus. 3rd. The <i>subscapularis</i> muscle (19, Fig. <a href="#i_194">68</a>)
+occupies the subscapular fossa, and is inserted into the lesser
+tuberosity of the humerus.</p>
+
+<p>The <i>serratus magnus muscle</i> (14, Fig. <a href="#i_194">68</a>; 5, Fig. <a href="#i_197">70</a>; 2, Fig. <a href="#i_200">71</a>;
+20, Fig. <a href="#i_207">73</a>).—This muscle, applied to the lateral part of the thorax,
+is hidden throughout a great part of its extent by the scapula and the
+muscles of the chest and shoulder; but it becomes superficial at its
+lower part, in a series of prominent digitations and muscular bands,
+which form very characteristic features in the contour of the lateral
+region of the thorax. At the same time, as the muscle constitutes the
+inner wall of the armpit, we must describe it here in detail.</p>
+
+<p>The serratus magnus arises by nine fleshy slips from the outer surfaces
+of the upper eight ribs (an additional slip arising between the first
+and second ribs). From this origin the muscle, which forms a broad
+sheet, sweeps backwards round the ribs, to be inserted into the whole
+length of the vertebral border of the scapula. The five or six upper
+digitations of the muscle are hidden by the great pectoral muscle (21,
+Fig. <a href="#i_207">73</a>), and only its three or four lowest digitations are visible on
+the side of the thorax between the borders of the great pectoral muscle
+in front and the latissimus dorsi behind; they interdigitate with the
+upper slips of origin of the external oblique<span class="pagenum" id="Page_221">[221]</span> muscle of the abdomen
+(20 and 16, Fig. <a href="#i_207">73</a>). The alternations of origin of the serratus magnus
+and external oblique are seen when the muscle is contracted, as when
+the arm is thrust forward. When the arm is hanging loosely, or slightly
+raised, we see only three digitations of the serratus magnus; but when
+the arm is strongly elevated the great pectoral frequently leaves
+another uncovered.</p>
+
+<p>The action of this muscle is to fix the scapula, drawing this bone
+downwards and forwards, while the rhomboid, on the other hand, draws
+it upwards and backwards. Fixation of the scapula being necessary to
+afford a fixed point for the contraction of the muscles of the arm
+(particularly the biceps), it is easy to perceive that whenever the
+upper limb accomplishes a powerful effort, the lower digitations of
+the serratus magnus become clearly visible in the living model, as in
+a sword-thrust, wrestling, lifting from the ground a heavy body, or in
+pushing back an adversary, &amp;c.</p>
+
+<p>The serratus magnus muscle forms the inner wall of the armpit or
+axilla, a cavity of which the anterior wall is represented by the
+pectoral muscles, and the posterior wall by the subscapularis, teres
+major, and latissimus dorsi. The cavity forms a triangular pyramid; its
+summit, directed upwards, corresponds in the skeleton to the interval
+between the first rib, the clavicle, and the upper border of the
+scapula. In a dissected subject this cavity is open inferiorly, but
+in the living model it is closed by the skin which forms the base of
+the pyramid, and which, in passing from the outer border of the great
+pectoral muscle to the border of the latissimus dorsi,<span class="pagenum" id="Page_222">[222]</span> is hollowed out
+so as to ascend in the space, into which it is drawn by its attachment
+to the strong, deep fascia of the axilla.</p>
+
+<p>To complete the description of the axilla we must say a few words
+concerning its boundaries, and the folds which correspond to the
+lines of junction of its walls. There is nothing more to add with
+regard to its anterior limit (formed by the great pectoral muscle) or
+its posterior limit (formed by the latissimus dorsi and teres major
+muscles clothing the axillary border of the scapula), but a word must
+be said of the external limit of the space which corresponds to the
+root of the arm. This is a comparatively thick surface, and corresponds
+to the upper part of the shaft of the humerus. The bone is covered
+by two muscles which descend from the scapula towards the anterior
+surface of the arm,—the <i>biceps</i> and <i>coraco-brachialis</i>,
+which we will notice briefly. We will say, first of all, that the form
+of the coraco-brachialis is clearly visible beneath the skin of the
+armpit when the arm is strongly raised, as for example in a subject
+crucified, when it raises the depressed skin in the armpit. The skin is
+covered with hair more or less abundant, according to the individual,
+and it is a classic habit to omit this part of the hairy system in
+every representation of an elevated limb; but the artist should be
+convinced by the study of anatomy that he should never conform to the
+habit of tracing on the skin of the hollow of the armpit a fanciful
+contour, since this skin is smooth and regularly depressed, and only
+on its external part presents the fusiform muscular prominence of the
+coraco-brachialis, on the inner side<span class="pagenum" id="Page_223">[223]</span> of the anterior surface of the
+arm. The <i>biceps</i> muscle escapes from under cover of the great
+pectoral muscle, and lies external to the coraco-brachialis more on the
+front of the limb.</p>
+
+<p>The <i>triceps</i> muscle of the arm, which, by its long head,
+takes origin from the scapula, does not pass, like the biceps and
+coraco-brachialis, through the armpit, but appears behind it on the
+back of the arm, since, as we have already said, it passes between
+the teres minor posteriorly and the teres major and latissimus dorsi
+anteriorly (Figs. <a href="#i_207">73</a> and <a href="#i_225">75</a>).</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_224">[224]</span></p>
+
+<h2>CHAPTER XIX.<br>
+<span class="subhed">MUSCLES OF THE ARM.</span></h2></div>
+
+<div class="blockquot">
+
+<p class="hangingindent">1st. Anterior muscles: <i>Biceps</i>, its two heads; its
+fusiform body; its bifurcation below (aponeurotic expansion
+and tendon); its action (supinator and flexor of forearm);
+influence of its aponeurotic expansion on the contour of the
+forearm.—<i>Coraco-brachialis</i>, <i>brachialis anticus</i>.
+2nd. Posterior muscle: <i>Triceps brachialis</i>, its three
+portions, flat surface formed by its inferior tendon; general
+contour of the posterior surface of the arm; action of triceps.
+External form of the arm; external and internal intermuscular
+grooves.</p>
+</div>
+
+
+<p>The muscles of the arm form two distinct fleshy masses, a mass in front
+formed by the <i>biceps</i>, which occupies the entire length of the
+arm; by the <i>coraco-brachialis</i>, which occupies only the upper
+part; and lastly, by the <i>brachialis anticus</i>, which occupies
+the lower part; and a mass behind, formed by one muscle only, the
+<i>triceps</i>.</p>
+
+<p>The <i>biceps</i> (12, Fig. <a href="#i_225">75</a>, and 21, Fig. <a href="#i_197">70</a>) is so called because
+it possesses two heads of origin, which are known by the names of
+the <i>long</i> and <i>short heads</i>. The <i>long head</i> of the
+muscle presents the form of a long tendon, which arises from the upper
+limit of the glenoid cavity of the scapula, and descends through the
+shoulder-joint and the bicipital groove of the humerus to the arm.
+The <i>short head</i> of the biceps has a less complex course, and
+arises from the summit of the coracoid process, in common with the
+coraco-brachialis.</p>
+
+  <div class="figcenter" id="i_225" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_225.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 75.</p>
+     <p class="p0 sm"><span class="smcap">The Muscles of the Shoulder and Arm</span> (seen from
+the external side).—1, the triceps brachialis;—2, its
+long head;—3, its external head;—4, its attachment to the
+olecranon;—5, the teres major;—5′, the teres minor;—6,
+the infraspinatus;—7, 8, 9, 10, the deltoid;—11, the
+supraspinatus;—12, the biceps brachialis;—13, the brachialis
+anticus;—14, the supinator longus;—15, extensor carpi radialis
+longior.</p>
+  </div>
+
+<p>These two tendons (long and short head) descend in the outer wall of
+the axilla, covered by the great<span class="pagenum" id="Page_225">[225]</span> pectoral muscle (Fig. <a href="#i_197">70</a>, page 197);
+a little above the lower border of this muscle the fleshy fibres appear
+and form two cylindrical bellies which descend and become united, at
+the level of the middle of the anterior surface of the arm, in one
+large mass, very marked in muscular subjects (12, Fig. <a href="#i_225">75</a>). A short
+distance above the elbow-joint, a flat tendon of insertion succeeds
+to the fleshy muscle; it is at first broad, but soon divides into two
+parts, one aponeurotic, called the <i>semi-lunar fascia</i> of the
+biceps; the other, a rounded tendon forming the chief insertion of the
+muscle. The aponeurotic expansion (2, Fig. <a href="#i_234">77</a>) of the bicipital fascia
+is directed downwards and inwards over the common mass of the flexor
+muscles of the forearm, and soon<span class="pagenum" id="Page_226">[226]</span> becomes blended with the aponeurosis
+of the forearm; the tendon proper (3, Fig. <a href="#i_217">74</a>) dips down in the hollow
+of the elbow between the internal and external muscles of the forearm,
+and is fixed to the bicipital tubercle of the radius (page 78, and Fig.
+<a href="#i_070">21</a>), upon which it turns to be inserted into the posterior part of the
+tubercle.</p>
+
+<p>The biceps muscle is essentially the flexor of the forearm on the arm.
+This action is evident, and known to all, and it is useless to dwell
+on it, except to recall the fact that the biceps, in acting on the
+forearm, is inserted perpendicularly on the lever which it moves, so
+that it is in the most favourable position for the exercise of all its
+power. But the contraction of the biceps produces along with flexion
+of the elbow two other movements to which it is important to direct
+attention. 1st. If the forearm is in pronation the tendon of the
+biceps is obviously twisted round the upper part of the radius, since
+it is inserted into the posterior part of the bicipital tubercle; the
+first effect produced, therefore, by its contraction is a rotation
+of the radius outwards, and a movement of supination; the biceps is,
+therefore, a supinator, and one of the most powerful. 2nd. Besides
+flexion at the elbow-joint and this movement of supination, the biceps
+muscle raises and draws inwards the humerus by its action on the
+shoulder-joint. The three separate movements are found in association
+with one another in such a movement as the act of raising the hand to
+the mouth.</p>
+
+<p>During the contraction of the biceps, its aponeurotic expansion is
+tightened, and binds down the mass of the flexor muscles of the forearm
+over which<span class="pagenum" id="Page_227">[227]</span> it passes; hence it marks on the inner surface of the
+fleshy part of this portion of the limb, two fingers’ breadth below the
+internal condyloid ridge, a distinct furrow, during the contraction of
+the muscle.</p>
+
+<p>The changes of form in the arm which accompany the contraction of the
+biceps are well known, and it is sufficient to recall the fact that
+the fleshy belly of this fusiform muscle is lengthened in the state of
+repose, becoming short and globular during contraction. Nothing is more
+striking, nor gives a better idea of the change of form in a muscle
+during contraction, than to examine the biceps in a model, who brings
+it gradually into action by flexing the forearm on the arm (Fig. <a href="#i_228">76</a>).
+We then see on the anterior surface of the arm a kind of fleshy ball
+becoming more and more clearly marked, which hardens and swells up at
+the same time, so that it seems to mount up towards the upper part of
+the arm, to the inferior border of the great pectoral muscle.</p>
+
+<p>The <i>coraco-brachialis</i> muscle forms a narrow fusiform fleshy
+mass, which occupies the upper part of the inner surface of the arm. It
+arises from the coracoid process of the scapula (alongside the short
+head of the biceps), and is inserted into the middle of the internal
+border of the humerus. When the arm is hanging loosely the lower half
+only of this muscle is visible on the subject, and its prominence is
+blended with that of the biceps, while its upper half is hidden within
+the axillary space, beneath the great pectoral muscle. It becomes
+visible beneath the skin of the armpit, however, when the arms are
+raised, as in the position on the cross, and we have<span class="pagenum" id="Page_228">[228]</span> already dwelt
+upon the contour which the fusiform muscular belly of this muscle
+presents in the outer wall of the axilla. When the coraco-brachialis
+contracts, its form becomes more prominent, like that of every muscle
+in contraction; but it is not more visible on this account, for as it
+draws the arm to the thorax against which it is applied, it conceals by
+this movement the region in which its prominence is marked.</p>
+
+  <div class="figcenter" id="i_228" style="max-width: 400px">
+     <img
+    class="p2"   
+    src="images/i_228.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 76.</p>
+     <p class="p0 sm center">A, the arm extended; B, the elbow flexed and the biceps contracted.</p>
+  </div>
+
+<p>The <i>brachialis anticus</i> muscle (13, Fig. <a href="#i_225">75</a>, and 4, 4, Fig.
+<a href="#i_234">77</a>).—Situated beneath the lower half of the biceps, which it overlaps
+on each side, this muscle is deeply placed, and covers the lower
+two-thirds of the anterior surface of the humerus, to which it is
+attached. The fleshy fibres descend almost to the level of the elbow,
+where they are replaced by a flat<span class="pagenum" id="Page_229">[229]</span> tendon, inserted into the front of
+the coronoid process of the ulna. As the ulna does not exhibit any
+of the lateral movements comprised in supination and pronation, the
+brachialis anticus is simply a flexor of the forearm, and when this
+movement is forcibly accomplished, it may be seen to swell up on each
+side of the lower part of the biceps.</p>
+
+<p><i>Triceps muscle.</i>—This muscle (21, 22, Fig. <a href="#i_207">73</a>; 1, 2, 3, Fig.
+<a href="#i_225">75</a>), which forms alone the entire muscular structure of the posterior
+surface of the arm, has been called the <i>triceps</i> because it
+arises by three heads, separated above, united below; one central
+or median, called the <i>long head</i>, and two lateral parts,
+distinguished as the <i>external</i> and <i>internal heads</i>. The
+<i>long head</i> (2, Fig. <a href="#i_225">75</a>), forming a thick and fusiform fleshy
+belly, arises by a stout tendon from the upper part of the axillary
+border of the scapula immediately below the glenoid cavity, and passes
+between the teres major and teres minor muscles to the back of the arm
+(page 223). At the level of the junction of the middle with the lower
+third of the arm, the fleshy belly terminates in a broad, flat tendon
+(1, Figs. <a href="#i_228">75</a> and <a href="#i_240">78</a>) which forms the main insertion of the muscle, and
+receives the insertions of the two other portions of the muscle. The
+<i>external head</i> (3, Fig. <a href="#i_225">75</a>) arises from the upper part of the
+posterior surface of the humerus (above and to the outer side of the
+spiral groove), and is directed obliquely downwards and inwards to be
+attached to the external border of the main tendon almost as low down
+as the elbow. Lastly, the <i>internal head</i> (22, Fig. <a href="#i_207">73</a>)<span class="pagenum" id="Page_230">[230]</span> arises
+from the lower part of the posterior surface of the humerus (below
+and to the inner side of the spiral groove), and is attached to the
+internal border and deep surface of the inferior common tendon. This
+tendon is inserted (4, Fig. <a href="#i_225">75</a>) into the upper surface of the olecranon
+process of the ulna, and on either side of this it blends with the deep
+fascia of the forearm.</p>
+
+<p>The form of the posterior surface of the arm is greatly influenced
+by the presence of the inferior common tendon of the triceps, which,
+narrow and pointed towards its upper end, forms a large flat surface
+at the lower part of the arm. This flat surface is overlapped on each
+side by the prominence of the fleshy parts of the inner and outer
+heads. Above, in the upper two-thirds of the posterior surface of the
+arm, two fleshy bellies may be seen side by side, an outer one formed
+by the outer head, an inner one formed by the long head of the muscle.
+The inner head, more deeply placed, is only obvious in the lower third
+of the arm. These various details—viz., the tendinous flat surface
+above the olecranon, the muscular prominences which bound it on each
+side, and the two fleshy bellies which ascend above it—become visible
+in a marked degree when the subject forcibly extends the forearm on the
+arm, as in struggling against any resistance which causes the position
+of flexion to be maintained. It is hardly necessary to say that the
+triceps is essentially the extensor muscle of the forearm on the arm.</p>
+
+<p>It is not only for the purpose of a regular<span class="pagenum" id="Page_231">[231]</span> enumeration, but also
+with regard to the anatomical interpretation of their external forms,
+that we have classed the muscles of the arm as anterior and posterior.
+On each side of the arm at both inner and outer borders, a groove
+runs which separates the anterior from the posterior muscles. In
+each of these grooves is a fibrous partition called the internal and
+external intermuscular septum, which extends from the surface to the
+corresponding supra-condyloid ridge of the humerus, and serves to
+increase the area of muscular attachment. In muscular contraction,
+therefore, each septum or aponeurosis is slightly drawn towards
+the humerus, and on the surface two grooves are clearly seen, each
+corresponding to an interval, internally or externally, between the
+anterior and posterior muscles.</p>
+
+<p>The internal groove commences at the inferior extremity of the
+coraco-brachialis, and descends almost to the inner condyle. Above it
+is faintly marked, because the numerous nerves and vessels surrounded
+by cellular tissue fill up the intermuscular space at this level;
+below it spreads out, and tends to be confounded with the form of the
+internal part of the brachialis anticus.</p>
+
+<p>The external groove (Fig. <a href="#i_225">75</a>) is short. It begins at the level of the
+lower extremity of the deltoid, and does not descend to the external
+condyle, because the highest muscles of the extensor group belonging
+to the forearm arise from the lower part of the outer border of the
+humerus, so that the groove is filled up by these muscles as they curve
+forwards towards the bend of the elbow.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_232">[232]</span></p>
+
+<h2>CHAPTER XX.<br>
+<span class="subhed">MUSCLES OF THE FOREARM AND HAND.</span></h2></div>
+
+<div class="blockquot">
+
+<p class="hangingindent">Division into groups:—A. Anterior muscles of the forearm.
+The <i>superficial muscles</i>, or <i>those arising from the
+inner condyle</i>: pronator radii teres, flexor carpi radialis,
+palmaris longus, and flexor carpi ulnaris. 2nd. The <i>deep
+muscles</i> (flexors of the fingers and pronator quadratus). B.
+Posterior muscles of the forearm. 1st. <i>External muscles</i>:
+supinator longus (importance with regard to the forms of the
+external region of elbow); the extensor carpi radialis, longior,
+and brevior; the supinator radii brevis. 2nd. The <i>posterior
+superficial muscles</i>: the extensor communis digitorum,
+extensor minimi digiti, extensor carpi ulnaris, and anconeus.</p>
+</div>
+
+
+<p><i>Muscles of the Forearm.</i>—The two bones of the forearm are
+covered by a series of muscles with fleshy bellies, generally fusiform,
+terminating inferiorly in tendons which are frequently very long, and
+become prominent in the region of the wrist. Some of these muscles move
+the forearm on the arm, or the radius on the ulna, but the action of
+the greater number is to move the hand on the forearm and the different
+segments of the fingers on each other. These muscles are divided into
+five series, each composed of four muscles, making the total number of
+muscles in the arm twenty altogether. We shall dwell chiefly upon the
+superficial muscles, a short mention being sufficient for the deeper
+ones. We distinguish first of all two groups, anterior and posterior:
+one on the front, the other on the back of the forearm. The anterior
+group is divisible into: 1st. An anterior superficial layer, of which<span class="pagenum" id="Page_233">[233]</span>
+each muscle will be studied; 2nd. An anterior deep layer, to which we
+will briefly refer. The posterior group may be subdivided into three:
+1st. An external layer; 2nd. A superficial posterior layer, which we
+must review in detail; and 3rd. A posterior deep layer, respecting
+which we shall only say sufficient to enable the reader to understand
+the shape of the wrist formed by the corresponding tendons.</p>
+
+<p>A. <i>ANTERIOR MUSCLES OF THE FOREARM.</i> I. <i>Anterior superficial
+muscles.</i>—All these muscles arise by a common tendon from the
+<i>internal condyle</i> of the humerus; their common origin does not
+appreciably extend above the level of the condyle, so that at the inner
+side of the elbow, contrary to what takes place on the outer side, the
+muscles of the forearm do not ascend on the corresponding side of the
+upper arm. If from the inner condyle we draw four lines, of which the
+first goes towards the middle of the radius, the second towards the
+outer border of the wrist, the third towards the middle, and the fourth
+towards the inner border of the wrist; these four lines, of which the
+first is very oblique and the others gradually approach the vertical,
+will give us the direction of each of these four anterior superficial
+muscles of the forearm, which are, in the order of the lines, from
+without inwards, the <i>pronator radii teres</i>, the <i>flexor carpi
+radialis</i>, the <i>palmaris longus</i>, and the <i>flexor carpi
+ulnaris</i>.</p>
+
+  <div class="figcenter" id="i_234" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_234.jpg"
+     alt="">
+     <p class="p0 sm"><span class="smcap">Fig. 77.</span>—<span class="smcap">The Anterior Muscles of the Left
+Forearm.</span>—1, the biceps brachialis;—2, its aponeurotic
+expansion;—3, its tendon;—4, 4, brachialis anticus;—5, the
+internal head of the triceps;—6, pronator radii teres;—7,
+flexor carpi radialis;—8, 9, palmaris longus;—10, flexor
+carpi ulnaris;—11, its attachment to the pisiform bone;—12,
+13, supinator longus;—14 and 15, the extensor carpi radialis,
+longior, and brevior;—16, the abductor longus pollicis;—17,
+its tendon;—18, tendon of extensor longus pollicis;—19, 20,
+21, the superficial flexor of the fingers and its tendons;—22,
+tendons of the deep flexors;—23, 23, the lumbricales;—24,
+abductor brevis pollicis;—26, flexor longus pollicis.</p>
+  </div>
+
+<p>The <i>pronator teres</i> (6, Fig. <a href="#i_234">77</a>) is fleshy throughout the
+entire extent in which it is visible on the model; arising from the
+internal condyle, it is directed obliquely downwards and outwards,
+and<span class="pagenum" id="Page_234">[234]</span> disappears beneath the external muscles of the forearm (supinator
+longus) to be inserted into the radius (around which it is slightly
+twisted) in the middle of its external surface (impression for the
+pronator teres, page 78). Contracting, the pronator teres turns the
+radius forward and inwards, producing pronation. This muscle forms the
+inner side, very oblique, of a triangular pit, known as the <i>hollow
+of the elbow</i>, of which the outer side is formed by the supinator
+longus (12, Fig. <a href="#i_234">77</a>). In this hollow the tendon of the biceps dips down
+(3, Fig. <a href="#i_234">77</a>) along with the brachialis anticus (4, 4, Fig. <a href="#i_234">77</a>) to be
+inserted into the bones of the forearm. The upper part of the pronator
+teres is crossed<span class="pagenum" id="Page_235">[235]</span> by the aponeurotic expansion of the biceps (2, Fig.
+<a href="#i_234">77</a>), and we have already dwelt on the particulars of external form
+which result from this arrangement.</p>
+
+<p>The <i>flexor carpi radialis</i> (7, Fig. <a href="#i_234">77</a>) arises from the inner
+condyle by a fusiform fleshy belly which descends obliquely to the
+middle of the forearm. It is replaced by a narrow, strong tendon which
+gains the outer part of the wrist, and then disappears beneath the
+annular ligament of the carpus, and, lying in a groove on the anterior
+surface of the trapezium, is inserted into the bases of the metacarpal
+bones of the fore and middle fingers. This muscle flexes the hand on
+the forearm; when it contracts, its tendon becomes very prominent and
+raises the skin at the lower part of the front of the forearm; it forms
+the first tendinous prominence that we meet at this level in passing
+from the radial to the ulnar border, and lies just internal to the
+groove in which the radial artery pulsates.</p>
+
+<p>The <i>palmaris longus</i> (8, 9, Fig. <a href="#i_234">77</a>) is much smaller than the
+preceding muscle; arising from the internal condyle, it forms a short
+fusiform fleshy belly (8) to which a long slender tendon succeeds.
+Descending almost vertically to the middle of the wrist, the tendon
+ends by being inserted into the annular ligament of the carpus and the
+fascia of the palm (9, Fig. <a href="#i_234">77</a>). The palmaris longus flexes the hand
+on the forearm, and its tendon forms in contraction of the muscle a
+well-marked prominence situated in the middle of the lower part of the
+front of the forearm on the inner side of the tendon of the flexor
+carpi radialis. In some subjects this muscle is<span class="pagenum" id="Page_236">[236]</span> absent, and it is
+frequently subject to variations of form.</p>
+
+<p>The <i>flexor carpi ulnaris</i> (10, 11, Fig. <a href="#i_234">77</a>) arises not only from
+the inner condyle, like the three preceding muscles, but also (18, Fig.
+<a href="#i_240">78</a>) from the posterior border of the ulna (including the olecranon)
+process; it descends vertically over the ulna, and is inserted by
+tendinous and fleshy fibres into the pisiform bone of the carpus (11,
+Fig. <a href="#i_234">77</a>). As its fleshy fibres continue down to its insertion the form
+of the muscle is not marked by a prominence such as those produced by
+the tendons of the preceding muscles; this muscle, therefore, helps
+to give a rounded form to the whole extent of the inner border of the
+forearm. It flexes the hand, and at the same time draws it inwards
+towards the inner side of the wrist.</p>
+
+<p>II. <i>Anterior deep muscles.</i>—These muscles constitute a fleshy
+mass lying beneath the preceding superficial muscles, and terminate
+near the wrist in numerous tendons, which pass to the fingers; the
+tendons of the muscles appear to a slight extent on the model in the
+grooves between the tendons of the superficial muscles (19, 19, Fig.
+<a href="#i_234">77</a>). Lower down the tendons of these muscles lie in the anterior groove
+of the carpus, bound down by the corresponding annular ligament, and
+after traversing the hollow of the palm of the hand, they are inserted
+into the phalanges of the fingers, presenting characteristic features
+which we will rapidly point out in the enumeration of these muscles.</p>
+
+<p>These deep muscles comprise, 1st, the <i>flexor sublimis digitorum</i>
+(19, Fig. <a href="#i_234">77</a>), which divides<span class="pagenum" id="Page_237">[237]</span> below into four tendons, one for each
+finger (except the thumb); 2nd, the <i>flexor profundus digitorum</i>,
+which also divides into four tendons, one for each finger (except the
+thumb). On the anterior surface of each finger, therefore, we see two
+tendons—one superficial (23, Fig. <a href="#i_234">77</a>) and the other deep. The first
+(flexor sublimis) presents at the level of the first phalanx (20, Fig.
+<a href="#i_234">77</a>) a slit or button-hole, through which the second passes (flexor
+profundus); owing to this arrangement the tendon of the deep flexor is
+inserted into the base of the third phalanx (22, Fig. <a href="#i_234">77</a>).
+superficial flexor is inserted into the base of the second phalanx (21,
+There is, indeed, a flexor muscle for each of the phalanges;
+the first phalanges of the fingers having special flexors in addition,
+the small <i>lumbricales</i> muscles of the palm of the hand, which
+arise from the sides of the tendons of the flexor profundus digitorum
+in the palm of the hand.</p>
+
+<p>3rd. The <i>flexor longus pollicis</i> (26, Fig. <a href="#i_234">77</a>) arises in the
+forearm from the radius, and its tendon is inserted into the base of
+the second or last phalanx of the thumb. It gives no evidence of its
+existence on the surface. 4th. The <i>pronator quadratus</i> muscle,
+a quadrilateral fleshy muscle, is disposed in a different manner to
+the preceding muscles, which must be raised in order to see it. It is
+formed by transverse fibres placed in the lower fourth of the forearm,
+and it passes from the anterior surface of the ulna to that of the
+radius. Its contraction produces pronation, rotating the radius over
+the lower part of the shaft of the ulna.</p>
+
+<p>B. <i>POSTERIOR MUSCLES OF THE<span class="pagenum" id="Page_238">[238]</span> FOREARM.</i> I. <i>External
+muscles.</i>—These form the fleshy mass which covers the lower third
+of the outer border of the arm (Fig. <a href="#i_225">75</a>, page 225) and descends along
+the outer border of the radius in the forearm. The group comprises
+four muscles—the <i>supinator longus</i> (<i>brachio-radialis</i>),
+two <i>radial extensors of the carpus</i>, and the <i>supinator radii
+brevis</i>.</p>
+
+<p>Of these four muscles, one only is visible on the model throughout
+its entire extent—viz., 1st, the <i>supinator longus</i> or
+<i>brachio-radialis</i> (14, Fig. <a href="#i_225">75</a>; 12, 13, Fig. <a href="#i_234">77</a>), which arises
+from the outer supra-condyloid border of the humerus, between the
+brachialis anticus in front and the triceps behind. It is noteworthy
+that on this side the muscles of the forearm ascend on the arm almost
+up to the insertion of the deltoid. The supinator longus enlarges as
+it descends, so that it presents its greatest size at the level of the
+external condyle, the prominence of which it completely conceals. It
+forms the outer vertical boundary (page 234) of the triangular hollow
+at the bend of the elbow. Just below the middle of the forearm, the
+fleshy fibres are replaced by a long tendon which lies on the radius,
+and (13, Fig. <a href="#i_234">77</a>) is finally inserted into the base of the styloid
+process of that bone. Notwithstanding its name, this muscle is not
+essentially a supinator; it acts in this way only when the forearm is
+in a position of complete pronation, and its proper action in this
+respect is to bring the forearm into a position between supination
+and pronation. Its principal function, however, is the flexion of the
+forearm on the arm, and in this movement its form is clearly shown
+externally in the form of a prominent band, which rises from the arm,
+and forms,<span class="pagenum" id="Page_239">[239]</span> on the antero-external part of the elbow, a strong fleshy
+mass, filling up the hollow produced by the flexion of the forearm on
+the arm. The supinator longus is the most important of the muscles of
+the forearm with regard to the part it takes in the external form of
+this region.</p>
+
+<p>The two next muscles (14 and 15, Fig. <a href="#i_234">77</a>) are partly hidden by the
+preceding; they are the <i>radial extensors of the carpus</i> (2 and
+3), distinguished as the <i>extensor carpi radialis</i>, <i>longior</i>
+and <i>brevior</i> (15, Fig. <a href="#i_225">75</a>). They arise from the lower part of
+the outer supra-condyloid ridge of the humerus and from the outer
+condyle, and form fleshy masses (3 and 5, Fig. <a href="#i_240">78</a>), which increase
+the prominence of the supinator longus, and help to conceal the outer
+condyle. At about the same level as in the case of the supinator
+longus, a tendon succeeds the fleshy belly of each of these muscles,
+and inclines a little backward (Fig. <a href="#i_240">78</a>); having been crossed by
+the <i>extensor ossis metacarpi pollicis</i>, by the <i>extensor
+brevis pollicis</i> (7 and 8, Fig. <a href="#i_240">78</a>), and by the <i>extensor longus
+pollicis</i>; each reaches the dorsal surface of the wrist, and is
+inserted into the base of the metacarpal bone of the index finger
+(extensor carpi radialis longior), and into the base of the metacarpal
+bone of the middle finger (extensor carpi radialis brevior, 6, Fig. <a href="#i_240">78</a>).</p>
+
+<p>4th. Surrounding the upper part of the radius is a small deep muscle,
+which does not show on the model, and which we mention here only to
+point out that its presence increases the prominence of the muscular
+mass on the outer side of the elbow; this is the <i>supinator radii
+brevis</i>, formed by<span class="pagenum" id="Page_240">[240]</span> fibres which, arising from the humerus,
+elbow-joint, and ulna, are rolled round the back and outer side of
+the radius, and which acts so as to turn the bone backwards and thus
+produce supination.</p>
+
+<p>II. <i>Posterior superficial muscles</i> (Fig. <a href="#i_240">78</a>).—This group
+comprises the <i>extensor cemmunis digitorum</i>, the <i>extensor
+minimi digiti</i>, the <i>extensor carpi ulnaris</i>, and the
+<i>anconeus</i>. These four muscles arise from the external condyle,
+to which they are attached by a common tendon; from this origin
+they are directed downwards, the first almost vertically, the last
+(<i>anconeus</i>) very obliquely backwards and inwards.</p>
+
+  <div class="figcenter" id="i_240" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_240.jpg"
+     alt="">
+     <p class="p0 sm"><span class="smcap">Fig. 78.</span>—<span class="smcap">The Posterior Muscles of the Left
+Forearm.</span>—1, the tendon of triceps brachialis;—2,
+supinator longus;—3 and 4, extensor carpi radialis longior;—5
+and 6, extensor carpi radialis brevior;—7 and 8, extensor
+ossis metacarpi pollicis and extensor brevis pollicis;—9, 9,
+the extensor longus pollicis;—10, 10, the annular ligament
+of the wrist (dorsal aspect);—11, 12, the extensor communis
+digitorum and its tendons;—13, the tendon of the extensor
+indicis;—14, the tendon of the extensor minimi digiti;—15,
+16, extensor carpi ulnaris;—17, anconeus;—18, the flexor
+carpi ulnaris;—19, the posterior border of the ulna;—20,
+olecranon;—21, the inner condyle.</p>
+  </div>
+
+<p>1st. The <i>extensor communis digitorum</i> (11, Fig. <a href="#i_240">78</a>)<span class="pagenum" id="Page_241">[241]</span> forms a long
+fusiform fleshy belly. In the lower third of the posterior surface of
+the forearm, it gives place to a tendon which soon subdivides into four
+bands. These remain in contact until they have passed a groove situated
+in the centre of the inferior extremity of the radius, and separate on
+the dorsal surface of the wrist, diverging so as to be attached to each
+of the four fingers. On the back of the hand the tendons of the middle,
+ring, and little fingers are joined together by two oblique tendinous
+slips directed obliquely downwards and outwards, from the fourth to the
+third, and from the third to the second tendon respectively. On the
+dorsal surface of the first phalanx of each finger (12, Fig. <a href="#i_240">78</a>) the
+extensor tendon forms a membranous expansion, and thereafter divides
+into three slips, a central one inserted into the base of the second
+phalanx, and two lateral slips which unite again to be inserted into
+the base of the third phalanx. The tendons cover the backs of the
+knuckles and of the joints of the fingers.</p>
+
+<p>2nd. The <i>extensor minimi digiti</i> is a small bundle of fleshy
+fibres lying adjacent to the preceding muscle, but distinctly detached
+from it. It gives rise to a separate tendon, which passes through a
+special groove beneath the posterior annular ligament between the lower
+ends of the radius and ulna. From the wrist it is directed towards the
+posterior surface of the little finger (14, Fig. <a href="#i_240">78</a>), where it unites
+with the tendinous fasciculi from the common extensor tendon for the
+little finger, and joins in the formation of<span class="pagenum" id="Page_242">[242]</span> the membranous expansion
+on the dorsum of the first phalanx.</p>
+
+<p>3rd. The <i>extensor carpi ulnaris</i> (15, Fig. <a href="#i_240">78</a>) is a fusiform
+muscle arising from the external condyle and the posterior surface
+of the ulna. It is replaced by a tendon in the lower fourth of the
+forearm (15, Fig. <a href="#i_240">78</a>). This tendon passes beneath the posterior annular
+ligament in a groove on the posterior surface of the ulna (10, Fig.
+<a href="#i_240">78</a>), and at the inner part of the dorsal surface of the carpus it
+terminates almost immediately by being inserted into the base of the
+metacarpal bone of the little finger (16, Fig. <a href="#i_240">78</a>).</p>
+
+<p>These three muscles are extensors of the fingers and hand. If we
+examine a living model which has the arm folded on the trunk, the
+dorsal surface of the forearm being turned forwards, and which quickly
+moves the fingers and hand, we see clearly the movements of the fingers
+marked by muscular movements in the upper two-thirds of the posterior
+surface of the forearm. We can, by following their prominences in
+contraction, clearly recognise the fusiform bellies of these muscles.</p>
+
+<p>4th. The <i>anconeus</i> occupies the upper part of the posterior
+surface of the forearm. As its name indicates (ἀγκὼν, olecranon,
+elbow), it is a muscle of the region of the elbow; it forms (17, Fig.
+<a href="#i_240">78</a>) a triangular fleshy mass, of which the apex is attached to the
+external condyle, and the base is inserted into the external surface
+of the olecranon, and corresponding part of the ulna (19, Fig. <a href="#i_240">78</a>). As
+the ulna does not possess appreciably the movement of rotation, but
+shares only in flexion and<span class="pagenum" id="Page_243">[243]</span> extension of the elbow-joint, the anconeus
+situated behind the joint has no other action than that of extending
+the forearm on the arm. When this movement is forcibly produced, we
+see the anconeus clearly marked by a triangular prominence, of which
+the upper border, the shortest, is united with the prominence of the
+triceps; and we have already mentioned the anatomical fact that the
+inferior portion of the triceps is directly continuous in the forearm
+with the anconeus muscle.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_244">[244]</span></p>
+
+<h2>CHAPTER XXI.<br>
+<span class="subhed">MUSCLES OF THE FOREARM AND HAND<br>(<i>continued</i>).</span></h2></div>
+
+<div class="blockquot">
+
+<p class="hangingindent">3rd. The posterior deep muscles of the forearm; their tendons at
+the level of the wrist (<i>anatomical snuff-box</i>).—Muscles
+of the hand;—1st. Muscles of the thumb, or <i>thenar
+eminence</i>. 2nd. Muscles of the little finger, or
+<i>hypothenar eminence</i>. 3. Short muscles of the palm
+(<i>lumbricales</i> and <i>interossei</i>).</p>
+</div>
+
+
+<p>III. <i>The deep posterior muscles</i> of the forearm, with regard to
+external form, are important only in the arrangement of their tendons
+in the wrist and hand; for this reason we describe them in this chapter
+along with the muscular structures of the hand and fingers.</p>
+
+<p>As in the other regions, we find in the deep part of the back of the
+forearm, four muscles. Proceeding from without inwards they are—the
+<i>extensor ossis metacarpi pollicis</i>, the <i>extensor brevis
+pollicis</i>, the <i>extensor longus pollicis</i>, and the <i>extensor
+indicis</i>. The fleshy bellies of these muscles are almost completely
+hidden beneath the posterior superficial muscles; but their tendons, at
+least those of the first three, emerge beneath the external border of
+the common extensor of the fingers, and their form is shown (7 and 8,
+Fig. <a href="#i_240">78</a>) by details of great importance on the outer side of the dorsal
+aspect of the wrist.</p>
+
+<p><span class="pagenum" id="Page_245">[245]</span></p>
+
+<p>The two first (7 and 8, Fig. <a href="#i_240">78</a>), the <i>extensor ossis metacarpi
+pollicis</i> (7) and the <i>extensor brevis pollicis</i> (8), must
+be described together, as their fleshy parts and tendons are placed
+together and are almost united throughout the greater extent of their
+course. These two muscles emerge in the lower third of the forearm, at
+the outer border of the common extensor of the fingers; and they form
+at this point, at the junction of the posterior surface with the outer
+border of the forearm, an oblong eminence, which is soon succeeded
+by a double tendon. Crossing the tendons of the radial extensors of
+the wrist, this double tendon is directed towards the outer surface
+of the lower end of the radius, where it passes through a groove (10)
+converted into a canal by the posterior annular ligament of the wrist.
+At the outer border of the wrist these two tendons form a prominence,
+well marked beneath the skin, when the thumb is separated from the
+other fingers. Finally, at the base of the metacarpal bone of the thumb
+these tendons separate, one, that of the <i>extensor ossis metacarpi
+pollicis</i>, being inserted into the base of the metacarpal bone,
+while the other, that of the <i>extensor brevis pollicis</i>, passes
+over the first metacarpal bone to be inserted into the base of the
+first phalanx of the thumb (8, at the level of the thumb, Fig. <a href="#i_240">78</a>).</p>
+
+<p>The <i>extensor longus pollicis</i> (9, Fig. <a href="#i_240">78</a>) emerges, like the
+preceding tendons, on the outer side of the common extensor, but lower
+down, on the back of the wrist; its tendon only becomes superficial at
+this point, and it is directed obliquely downwards through a prominent
+deep groove on the posterior surface of<span class="pagenum" id="Page_246">[246]</span> the lower end of the radius,
+where it is covered by the posterior annular ligament. On the back
+of the wrist the tendon is directed obliquely outwards, crossing the
+tendons of the radial extensors of the wrist, to reach the base of the
+metacarpal bone of the thumb, where it lies parallel to the tendon of
+the extensor brevis pollicis. Descending lower than this tendon it is
+finally inserted into the second or terminal phalanx of the thumb (9,
+Fig. <a href="#i_240">78</a>).</p>
+
+<p>The tendons of the extensor ossis metacarpi and extensor brevis
+pollicis on the one hand, and the extensor longus pollicis on the
+other, form on the outer part of the back of the wrist a triangular
+figure, of which the apex corresponds to the upper end of the thumb,
+and the base to the lower end of the radius. When we separate the thumb
+strongly from the index finger—that is to say, when we contract the
+three small muscles which we have been studying—the corresponding
+tendons mark the borders of this triangle in the form of prominent
+cords, between which is a deep concavity; to this depression is given
+the name of the <i>anatomical snuff-box</i> (4, Fig. <a href="#i_240">78</a>).</p>
+
+<p>The <i>extensor indicis</i> is not visible on the model; it is deeply
+situated beneath the common extensor of the fingers, and terminates
+in a tendon (13, Fig. <a href="#i_240">78</a>) which unites with the tendinous fibres from
+the common extensor to the index finger. It is to this muscle that
+the index finger owes its power of extension independent of the other
+fingers, and of performing the functions which have given it the name
+of the index or indicating finger. It is to be noted that in separate
+extension of the index finger (with flexion of the others) the tendon
+of the extensor<span class="pagenum" id="Page_247">[247]</span> communis digitorum in the back of the hand gets curved
+outwards, by being pulled into line with the extended index finger by
+the traction of the tendon of the extensor indicis (Macewen).</p>
+
+  <div class="figcenter" id="i_247" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_247.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 79.</p>
+     <p class="p0 sm"><span class="smcap">Muscles of the Hand</span> (palmar surface).—2, abductor
+pollicis (cut);—3, opponens pollicis;—4, flexor brevis
+pollicis;—5, adductor obliquus pollicis;—6, adductor
+transversus pollicis;—7, deep flexor tendons and lumbrical
+muscles;—8, flexor tendons on finger;—9, flexor longus
+pollicis;—10, abductor minimi digiti;—11, flexor brevis minimi
+digiti;—12, pisiform bone.</p>
+  </div>
+
+<p><i>Muscles of the hand.</i>—The numerous muscles belonging to the hand
+form an interesting study in relation to the mechanism of the multiple
+and delicate movements of the fingers, but as the various details of
+their complex arrangement do not show very plainly on the surface we
+may confine our study of them to an enumeration of their principal
+features.</p>
+
+<p>The dorsal region of the hand (Fig. <a href="#i_240">78</a>) does not possess any fleshy
+muscles, but only presents the tendons belonging to the muscles of
+the forearm. The arrangement of the tendons after passing beneath the
+posterior annular ligament has already been described (pp. 245–6).
+Notice should be taken of an arch of veins lying superficial to the
+tendons. This venous arch receives the veins from the fingers, and is
+variable in its arrangement and outline.</p>
+
+<p><span class="pagenum" id="Page_248">[248]</span></p>
+
+<p>On the other hand, the anterior or palmar region of the hand possesses,
+beside the tendons of the muscles of the forearm, numerous small
+muscles, which are divided into three groups:—1st, an external group
+associated with the thumb, forming the fleshy prominence known as
+the <i>thenar eminence</i>; 2nd, an internal group, belonging to the
+little finger, forming the <i>hypothenar eminence</i>; 3rd, a middle
+and deeper group, formed by small muscles belonging to the fingers, and
+placed deep in the hand beneath the thick <i>palmar fascia</i>, which,
+occupying the hollow of the palm, fills up the space between the thenar
+and hypothenar eminences (Fig. <a href="#i_247">79</a>).</p>
+
+<p>1st. The <i>thenar eminence</i> (2–5, Fig. <a href="#i_247">79</a>) is of a long ovoid
+form, with the large superior extremity corresponding to the carpus,
+and the smaller inferior extremity corresponding to the base of the
+first phalanx of the thumb. It is formed by six muscles, namely, the
+<i>abductor pollicis</i> (24, Fig. <a href="#i_234">77</a>; 2, Fig. <a href="#i_247">79</a>), which proceeds
+from the trapezium and annular ligament to the outer side of the first
+phalanx of the thumb; the <i>opponens pollicis</i> (3, Fig. <a href="#i_247">79</a>), with
+a similar origin, inserted into the entire length of the outer border
+of the first metacarpal bone, so that its contraction draws the whole
+thumb (phalanges and metacarpal bone) towards the palm of the hand, and
+thus opposes it to the other fingers; the <i>flexor brevis pollicis</i>
+(superficial part) (4, Fig. <a href="#i_247">79</a>), which proceeds from the annular
+ligament to the base of the first phalanx; the <i>adductor obliquus
+pollicis</i> (5, Fig. <a href="#i_247">79</a>), arising from the carpus and heads of the
+metacarpal bones, and inserted into the inner side of the first phalanx
+of the thumb; the <i>adductor transversus<span class="pagenum" id="Page_249">[249]</span> pollicis</i> (6, Fig. <a href="#i_247">79</a>), a
+muscle remarkable for its arrangement, for it arises from the middle of
+the palm of the hand, from the anterior surface of the third metacarpal
+bone, and forming a comparatively broad fleshy mass, extends outwards
+to be inserted along with the adductor obliquus into the inner side of
+the base of the first phalanx of the thumb; and finally a small muscle
+deeply placed in the space between the first and second metacarpal
+bones, and known as the <i>deep part of the flexor brevis pollicis</i>
+(or the <i>interosseus primus volaris</i>).</p>
+
+<p>2nd. The <i>hypothenar eminence</i> is long and elliptical in form,
+but smaller than the thenar eminence; it is covered in part by a small
+muscle which is not shown by any external prominence, but only by the
+folds which it marks in the skin during its contraction; this is the
+<i>palmaris brevis</i>, formed of transverse fibres, which, arising
+from the inner border of the palmar fascia, is inserted into the deep
+surface of the skin on the inner border of the hand. The contraction of
+its fibres draws the skin of the part upwards and forms an irregular
+vertical furrow, so that the prominence of the skin of the upper part
+of the hypothenar eminence becomes more clearly marked. The hypothenar
+eminence itself is formed by three small muscles vertically arranged
+over the fifth metacarpal bone:—1, the <i>abductor minimi digiti</i>
+(28, Fig. <a href="#i_234">77</a>; 10, Fig. <a href="#i_247">79</a>), passing from the pisiform bone to the
+inner side of the first phalanx of the little finger; 2, the <i>flexor
+brevis minimi digiti</i> (27, Fig. <a href="#i_234">77</a>; 11, Fig. <a href="#i_247">79</a>), passing from the
+prominence of the unciform bone to the same phalanx; and lastly, 3,
+the <i>opponens minimi digiti</i>, arising from the unciform<span class="pagenum" id="Page_250">[250]</span> bone and
+inserted into the entire length of the fifth metacarpal bone, so that
+its contraction slightly draws outwards the whole of the little finger,
+and opposes it to a certain degree to the thumb.</p>
+
+<p>3rd. The muscles of the middle region of the palm of the hand are in
+two series. One set is arranged between the tendons of the <i>flexor
+profundus digitorum</i> muscle (see anterior deep muscles of the
+forearm, page 237) as small fusiform muscles, which have been compared
+to the form of a worm—hence their name of <i>lumbricales</i> (7, Fig.
+<a href="#i_247">79</a>). The others are arranged in the spaces between the metacarpal
+bones, and are known as the <i>interosseous</i> muscles.</p>
+
+<p>The <i>lumbricales</i> muscles, as Figure <a href="#i_234">77</a> shows (23, 23), are
+four in number—one for each of the four fingers. Their upper ends
+are attached to the deep flexor tendons; and from this origin they
+descend to reach the outer or radial border of the first phalanx
+of each finger. Sweeping round the knuckle on its outer side, each
+tendon is inserted into the metacarpo-phalangeal capsule, the outer
+side of the base of the first phalanx, and into the expansion of the
+extensor tendon on the dorsum of the first phalanx of each finger. In
+consequence of this mode of insertion each muscle is a flexor of the
+metacarpo-phalangeal joint, and in addition, because of its connection
+with the extensor tendon, it is at the same time an extensor of the
+inter-phalangeal joints.</p>
+
+<p>The <i>interosseous muscles</i> are seven in number, divided into two
+series, dorsal and palmar. The <i>dorsal</i> muscles, four in number,
+are found one in each interosseous space between the metacarpal bones.
+The three <i>palmar</i> interosseous muscles<span class="pagenum" id="Page_251">[251]</span> occupy the three inner
+spaces. They arise from the sides of the metacarpal bones (the dorsal
+muscles by double origins, the palmar muscles by single heads from the
+inner three metacarpal bones); and they are inserted in the same way as
+the lumbrical muscles into the fingers, so as to act as flexors of the
+metacarpo-phalangeal, and extensors of the inter-phalangeal joints. The
+several muscles pass in relation to the sides of the knuckles in a way
+that need not be detailed here, so as to occupy positions which enable
+them to act so as to separate or draw together the fingers. The dorsal
+interossei muscles serve to separate the fingers from each other, while
+the palmar serve to bring them together; or, to be more precise, the
+dorsal muscles abduct the fingers from the middle line of the middle
+finger, while the palmar muscles adduct the fingers on which they act
+(third, fourth, and fifth) towards the axis of the middle finger.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_252">[252]</span></p>
+
+<h2>CHAPTER XXII.<br>
+<span class="subhed">MUSCLES OF THE PELVIS AND THIGH.</span></h2></div>
+
+<div class="blockquot">
+
+<p class="hangingindent"><i>The Buttock.</i>—<i>Gluteus maximus</i>, its thickness
+and form; its relations to the great trochanter.—<i>Gluteus
+medius.</i>—The subjacent muscles (<i>gluteus minimus</i>,
+<i>pyriformis</i>, etc.).—Muscles of the thigh; 1st, External
+region <i>tensor fasciæ latæ</i> (<i>vaginæ femoris</i>),
+its importance with regard to external form; aponeurosis of
+<i>fascia lata</i>; 2nd, Anterior region, <i>sartorius</i>,
+peculiarities of this muscle during contraction; <i>quadriceps
+extensor</i> (<i>rectus</i>, <i>vastus internus</i>, <i>vastus
+externus</i>, <i>crureus</i>); 3rd, Internal region, the
+<i>adductors</i>; 4th, Posterior region, <i>hamstring</i>
+muscles (<i>biceps</i>, <i>semi-tendinosus</i>, and
+<i>semi-membranosus</i>).</p>
+</div>
+
+
+<p><i>Muscles of the Pelvis.</i>—The muscles of the pelvis visible on
+the model are all situated on the posterior surface of that part of
+the skeleton, and form the buttock, or <i>gluteal region</i>. In front
+the anterior wall of the abdomen, descending to Poupart’s ligament and
+the pubis (Fig. <a href="#i_197">70</a>, page 197), conceals the muscles which proceed from
+the interior of the pelvis towards the thigh—muscles of which a short
+sketch will be given along with those of the front of the thigh.</p>
+
+<p>Of the muscles of the gluteal region two only are superficial and well
+marked on the model—viz., the <i>gluteus maximus</i> and <i>gluteus
+medius</i>.</p>
+
+<p>The <i>gluteus maximus muscle</i> (Fig. <a href="#i_201">72</a>, page 201) is the largest
+and thickest of all the muscles of the body. It is composed of large
+fleshy fibres directed obliquely from the sacro-iliac region towards
+the upper part of the femur. Its fibres arise from the posterior
+extremity of the crest of<span class="pagenum" id="Page_253">[253]</span> the ilium (4, Fig. <a href="#i_107">34</a>, page 107), by an
+aponeurosis from the back of the sacrum, from the sacrum itself, and
+from the sacro-sciatic ligament. The coarse fleshy fibres are directed
+downwards and outwards through the gluteal region (Fig. <a href="#i_193">67</a>). At the
+level of the great trochanter these fibres are for the most part
+inserted into a broad, thick, tendinous lamina, which is continuous
+with the aponeurosis of the thigh or <i>fascia lata</i>. The lower
+and deeper part of the muscle is inserted directly into the gluteal
+ridge of the femur (page 133). The gluteus maximus muscle presents
+four borders: (1) an <i>internal border</i>, corresponding to its
+origin, and convex inwards, and (2) an <i>external border</i>, also
+slightly convex at its insertion. This border corresponds to the line
+along which the fleshy fibres terminate; it forms a prominence, which
+curves posteriorly round the great trochanter. When we have enumerated
+the muscles lying beneath the gluteus maximus, it will be more easy
+to understand how the muscular structure of the gluteal region as a
+whole is so prominent that the great trochanter actually forms on the
+model the centre of a depressed area, bounded behind and above by the
+prominence of the gluteal muscles, and in front by the tensor muscle of
+the fascia lata (see <i>Muscles of the thigh</i>). (3) The <i>inferior
+border</i> of the gluteus maximus is thick, and forms an oblique
+elevation, beneath which the posterior muscles of the thigh emerge; it
+is this which helps to form the lower limit of the prominence of the
+buttock. In the erect position the lower limit of the gluteal region is
+indicated<span class="pagenum" id="Page_254">[254]</span> by a transverse fold (<i>the fold of the nates</i>). This
+line runs diagonally across the lower border of the gluteus maximus,
+and is produced not by the edge, but by the weight of the relaxed
+muscle, and the fat which covers it. (4) The <i>superior border</i> is
+thin (Fig. <a href="#i_217">74</a>, page 217), and is continuous with the fascia lata, which
+covers the gluteus medius, so that its prominence is little marked on
+the model, being more or less lost in the area corresponding to the
+position of the gluteus medius muscle.</p>
+
+<p>The <i>gluteus maximus</i> is an extensor of the thigh on the pelvis.
+In the upright position it supports the pelvis behind and prevents it
+from inclining forwards. It is by its action that the trunk is raised
+so as to be in the same line as the upright lower limb. The gluteus
+maximus is therefore the muscle of the upright position, and we observe
+the large size which it presents in the human subject compared with its
+small proportions in animals which do not adopt the biped attitude.</p>
+
+<p>The <i>gluteus medius muscle</i> is situated both above and beneath
+that of the gluteus maximus—that is to say, the postero-inferior part
+is covered by the preceding muscle, but its antero-superior part is
+superficially placed. This latter part (Fig. <a href="#i_217">74</a>, between 22 and 23)
+is, however, covered by the thick fascia lata of the thigh, which
+binds down the muscle to the dorsum ilii. Arising from the anterior
+three-fourths of the crest of the ilium, and from the dorsum ilii as
+well as from the fascia over it, the fibres of the gluteus medius
+descend, converging towards the great trochanter, into the external
+surface of<span class="pagenum" id="Page_255">[255]</span> which they are inserted by a thick aponeurotic tendon. The
+fleshy fibres cease a little above the great trochanter so as to form
+a prominence along a curved line with its concavity downwards, which
+forms the superior boundary of the depression corresponding to the
+region of the great trochanter, referred to above. The gluteus medius,
+by its posterior fibres, acts like the gluteus maximus; by its anterior
+fibres it draws the thigh outwards, acting as an abductor.</p>
+
+  <div class="figcenter" id="i_255" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_255.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 80.</p>
+     <p class="p0 sm"><span class="smcap">The Deep Gluteal Muscles.</span>—1, Dorsum ilii;—2,
+sacrum;—3, posterior sacro-iliac ligament;—4, tuberosity of
+ischium;—5, great, 6, lesser sacro-sciatic ligament;—7, great
+trochanter;—8, gluteus minimus;—9, pyriformis;—10, 11, 12,
+gemelli and obturator internus 13, quadratus femoris;—14,
+adductor magnus;—15, vastus externus;—16, biceps and
+semi-tendinosus—17, gracilis;—18, semi-membranosus.</p>
+  </div>
+
+<p>The gluteus maximus and gluteus medius muscles conceal a series of deep
+muscles filling up the large space which we observe on the skeleton
+between the great trochanter and the pelvic wall. These muscles, which
+we only need to enumerate in order to understand the importance of the
+prominence of the buttock, are, taking them in order, as follows—the
+<i>gluteus minimus</i>, which lies exactly beneath the gluteus medius,
+and proceeds from the dorsum ilii to the superior and anterior border
+of the great trochanter;<span class="pagenum" id="Page_256">[256]</span> the <i>pyriformis</i>, which arises within
+the pelvis from the anterior surface of the sacrum, escapes from the
+pelvis through the great sciatic notch, and is directed obliquely
+towards the great trochanter, into the upper border of which its tendon
+is inserted; the <i>obturator internus</i>, which proceeds also from
+the interior of the pelvis, is reflected over the lesser sciatic notch
+and is inserted into the internal surface of the great trochanter
+along with two accessory muscles, the <i>gemelli</i>; and finally, the
+<i>quadratus femoris</i>, formed by short horizontal fibres, which
+extends from the outer part of the tuberosity of the ischium to the
+posterior surface of the femur between the two trochanters.</p>
+
+<p><i>Muscles of the thigh.</i>—The muscles of the thigh are arranged
+around the femur, and frequently in a direction so oblique that
+they appear in one portion, for example, on the front, and in
+another portion on the inner side of the thigh. We can, however,
+class them in four series—external, comprising the <i>tensor
+vaginæ femoris</i> (<i>fasciæ latæ</i>); anterior, comprising the
+<i>sartorius</i> and <i>quadriceps extensor</i>; internal, comprising
+the <i>adductors</i>; and posterior, comprising the <i>biceps</i>, the
+<i>semi-membranosus</i>, and the <i>semi-tendinosus</i>.</p>
+
+  <div class="figcenter" id="i_257" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_257.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 81.</p>
+     <p class="p0 sm"><span class="smcap">The Muscles of the Anterior Surface of the Right
+Thigh.</span>—1, the iliacus;—2, the psoas;—3, the tensor
+vaginæ femoris;—4, its tendon (fascia lata);—5, the
+sartorius;—6, the rectus (long head of quadriceps;—7, vastus
+externus (the external head);—8, vastus internus (the internal
+head);—9, the gracilis;—10, the adductor longus;—11, the
+pectineus.</p>
+  </div>
+
+<p>I. <i>Outer side of the thigh.</i> The <i>tensor vaginæ femoris
+muscle</i> (3, Fig. <a href="#i_257">81</a>).—This muscle lies in the plane of the gluteus
+maximus (23, Fig. <a href="#i_217">74</a>, page 217), and forms a distinct prominence in
+front of the great trochanter. It arises from the anterior superior
+spine of the ilium, and is directed downwards and slightly backwards
+on the outer side of the thigh, to terminate a short way below the
+level of the great trochanter by being inserted into the broad and
+thick aponeurosis—the<span class="pagenum" id="Page_257">[257]</span> <i>fascia lata</i>—which covers this region
+(4, Fig. <a href="#i_257">81</a>). This aponeurosis is specially thickened by the addition
+of vertical fibres, which form a tendon of insertion known as the
+<i>ilio-tibial</i> band. This band descends to the outer side of the
+knee as a distinct prominent tendon, which is inserted finally into
+the outer tuberosity of the tibia (see page 135). This muscle rotates
+outwards the thigh and the whole lower limb, and contributes also to
+the flexion of the thigh on the pelvis; therefore, when the thigh is
+extended and not turned inwards, the tensor muscle forms beneath the
+iliac spine a long muscular elevation, but when it is in action its
+form becomes short and broad, and forms a characteristic globular
+mass. This contrast in the form of the tensor muscle in repose and in
+action has been beautifully shown on<span class="pagenum" id="Page_258">[258]</span> the Gladiator, in which there is
+contraction of the tensor of the right thigh and relaxation of that of
+the left.</p>
+
+<p>The ilio-tibial band and the aponeurosis of the fascia lata cover, on
+the outer side of the thigh, the large fleshy mass of the <i>vastus
+externus</i> (a part of the quadriceps extensor muscle), which belongs
+to the anterior region of the thigh. This muscle, thus covered in,
+is shown throughout its entire extent on the surface. Though covered
+by the fascia lata, it forms a marked convexity on the outer side of
+the thigh, as a gentle curve in women, and a strongly bowed line in
+well-developed, muscular men.</p>
+
+<p>II. <i>Front of the Thigh.</i> The <i>sartorius muscle</i> (5, Figs.
+<a href="#i_257">81</a>, and 23, Fig. <a href="#i_197">70</a>, page 197).—This is the longest muscle in the
+human body. It forms a narrow fleshy band, which arises from the
+anterior superior iliac spine, and is directed obliquely downwards
+and inwards. Crossing the front of the thigh obliquely, it descends
+round the inner side of the knee over the inner condyle of the femur
+(Fig. <a href="#i_275">86</a>), describing a curve with the concavity forward. It finally
+terminates at the upper part of the inner surface of the shaft of the
+tibia in a flat tendon (19 and 20, Fig. <a href="#i_275">86</a>) which sweeps forward to be
+inserted into that bone just below the inner tuberosity in front of and
+along with the gracilis and semi-tendinosus muscles.</p>
+
+<p>The sartorius flexes and abducts the thigh on the pelvis, and flexes
+the leg on the thigh; so that it gives to the lower limb a position
+similar to that of a tailor when seated, hence the name of this muscle
+(<i>sartor</i>, a tailor). With regard to surface form, this muscle is
+indicated externally in a peculiar manner. When<span class="pagenum" id="Page_259">[259]</span> it contracts, only its
+superior extremity presents a superficial prominence; throughout the
+rest of its extent, the presence of the muscle, lying in the depressed
+groove between the quadriceps extensor in front and the adductor
+muscles on the inner side, is indicated during contraction by a large
+shallow furrow, particularly noticeable on the inner side of the thigh,
+at the junction of the upper two-thirds with the lower third.</p>
+
+<p><i>Quadriceps extensor</i> (6, 7, 8, Fig. <a href="#i_257">81</a>).—The quadriceps extensor
+muscle belongs to the outer and inner regions of the thigh as well
+as to the front of the limb, but the element of the muscle of most
+importance in relation to external form—the <i>rectus femoris</i>—is
+situated anteriorly. The muscle, as its name implies, is composed of
+four portions: one, the <i>rectus</i>, in the middle; the <i>vastus
+internus</i> and the <i>vastus externus</i>, on each side; and the
+<i>crureus</i>, the deepest part, concealed by the other portions of
+the muscle.</p>
+
+<p>The <i>rectus femoris</i> (21, Fig. <a href="#i_197">70</a>, and 6, Fig. <a href="#i_257">81</a>) is long and
+fusiform in shape—that is to say, larger at its centre than at its
+extremities. Its superior extremity, the more slender of the two,
+arises by a double tendon from the anterior inferior iliac spine
+and the dorsum ilii, and appears on the front of the thigh between
+the tensor fasciæ femoris and the sartorius muscles. Lying in the
+angular space which separates these two muscles (Fig. <a href="#i_257">81</a>), the rectus
+descends vertically on the front of the thigh, and about four inches
+above the patella forms a broad tendon (Figs. <a href="#i_257">81</a> and <a href="#i_270">84</a>), the borders
+of which give insertion on either side to the vastus internus and
+vastus externus muscles, while its deep surface gives<span class="pagenum" id="Page_260">[260]</span> insertion to
+the crureus muscle, and its base broadens out to be inserted into the
+patella. From the lower end of the patella a broad ligament—<i>the
+ligament of the patella</i>—arises (page 134), which is inserted into
+the tubercle of the tibia; it follows, therefore, that by means of the
+tendon of the rectus femoris, the patella, and the ligament of the
+patella, the quadriceps extensor muscle is eventually inserted into the
+tibia (Fig. <a href="#i_137">45</a>, page 137).</p>
+
+<p>The <i>vastus internus muscle</i> (8, Fig. <a href="#i_257">81</a>) is a very large fleshy
+mass, which covers the inner side of the femur. Arising from the
+inner lip of the linea aspera of the femur, from the edge of the bone
+(spiral line) above, and from the internal supra-condyloid ridge
+below, its muscular fibres are directed downwards and forwards, to be
+inserted into the deep surface and the inner border of the tendon of
+the rectus femoris, into the side of the patella, and into the capsule
+of the knee-joint. It conceals the crureus and partly blends with
+that muscle. The outline of the vastus internus is easily discernible
+on the surface, forming a somewhat triangular, convex, and rounded
+contour; bounded internally by the furrow of the sartorius, externally
+by a vertical line where it joins the tendon of the rectus femoris,
+and below by its lower border, it forms a well-marked rounded line
+sweeping outwards over the internal condyle of the femur to the side
+of the patella. These details are of great importance in regard to the
+contour of the region above the patella, and are in marked contrast, as
+we shall see, with the arrangement presented at the same level by the
+lower part of the vastus externus.</p>
+
+<p>The <i>vastus externus</i> (7, Fig. <a href="#i_257">81</a>) lies external to<span class="pagenum" id="Page_261">[261]</span> the rectus
+femoris, and conceals the crureus, with which its deep surface is
+partially blended. Its origin, which underlies the tensor fasciæ
+femoris and the ilio-tibial band, is from the upper half of the shaft
+of the femur, from the outer lip of the linea aspera. Its fibres sweep
+downwards and slightly forwards to be inserted into the tendon of the
+rectus, the patella, and the capsule of the knee-joint. The line along
+which it is inserted into the rectus tendon describes a curve of which
+the convexity looks towards the supero-external angle of the patella,
+from which it is separated by a considerable interval (Figs. <a href="#i_257">81</a> and
+<a href="#i_272">85</a>). Consequently on the surface the flat surface above the patella
+forms a sort of triangle, of which the borders are very different,
+the inner border being vertical, the outer one oblique, curved, and
+higher in position; the base of the triangle corresponds to the patella
+and the lateral parts of the capsule of the knee-joint; its truncated
+summit corresponds to the inferior extremity of the fleshy part of the
+rectus; and the borders of this flat surface, formed by the fleshy
+insertions of the vasti muscles, become very prominent when the leg is
+forcibly straightened on the thigh.</p>
+
+<p>The <i>crureus</i> muscle, deeply placed, is the fourth element in the
+quadriceps muscle. It arises from the upper three-fourths of the shaft
+of the femur, externally and in front, and forms a thick, fleshy mass,
+responsible to a great extent for the general contour of the front
+and sides of the thigh, though it is not actually noticeable directly
+on the surface. It is almost wholly concealed by the three previous
+muscles. It is partially blended on each side<span class="pagenum" id="Page_262">[262]</span> with the vasti muscles;
+and it is inserted as well into the deep surface of the tendon of the
+rectus femoris. It is hardly necessary to point out, since it is clear
+from its anatomical arrangement, that the quadriceps muscle, passing by
+means of the patella and the patellar ligament to the tubercle of the
+tibia, is essentially the extensor muscle of the leg.</p>
+
+<p>It is to be noted that the two vasti muscles have a very different
+effect in the shaping of the contours of the thigh. The vastus externus
+has its greatest prominence well above the patella on the outer side:
+the most prominent part of the vastus internus is formed by its lowest
+fibres, as they sweep across over the inner condyle of the femur.</p>
+
+<p>III. <i>The inner side of the thigh.</i> The <i>adductor
+muscles</i>.—We understand by <i>the adductors</i> the numerous
+muscles that occupy the inner part of the thigh, and which, passing
+down from the pubis and ischium along the entire length of the femur,
+fill up the triangular space which appears in the skeleton between
+the inner surface of the femur and the pubic part of the hip-bone.
+Some of the muscles of this series take the special name of adductors.
+We will study in succession three muscles clearly visible on the
+model—viz. the <i>pectineus</i>, the <i>adductor longus</i>, and the
+<i>gracilis</i>; afterwards we will mention briefly the muscles almost
+hidden by the preceding—namely, the <i>adductor brevis</i> and the
+<i>adductor magnus</i> muscles.</p>
+
+  <div class="figcenter" id="i_263" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_263.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 82.</p>
+     <p class="p0 sm"><span class="smcap">The Popliteal Region and Posterior Surface of the
+Right Leg.</span>—1, internal gastrocnemius;—2, external
+gastrocnemius;—3, space between gastrocnemii;—4, 5, tendo
+Achillis;—6, 7, 7, plantaris muscle and its tendon;—8, tendons
+of deep muscles (common flexor and posterior tibial);—9,
+peroneus longus;—10, peroneus brevis;—11, soleus;—12, biceps
+femoris;—13, semi-tendinosus;—14, semi-membranosus;—15,
+gracilis;—16, sartorius.</p>
+  </div>
+
+<p>The <i>pectineus muscle</i> (22, Fig. <a href="#i_197">70</a>, and 11, Fig. <a href="#i_257">81</a>), the first
+and shortest of the muscles of this region, is a broad fleshy band
+which extends from the horizontal ramus of the pubis to the upper<span class="pagenum" id="Page_263">[263]</span>
+part of the shaft of the femur (to a rough line passing from the
+linea aspera to the lesser trochanter). The lower part of this muscle
+is hidden by the sartorius, and the upper part does not show itself
+clearly beneath the skin, being covered by the large vessels of the
+thigh, and also in most cases by a quantity of fat. The pectineus
+forms the middle part of the floor of a triangular space in the
+upper third of the thigh, with its apex below, known in surgical
+anatomy as <i>Scarpa’s triangle</i>, which is bounded externally
+by the sartorius muscle. The base of the triangle corresponds to
+the groin, and is formed by Poupart’s ligament. The outer part of
+the floor of the triangle is formed by a large muscle, of which the
+greater part is situated in the cavity of the abdomen. This is the
+<i>ilio-psoas</i> muscle (1 and 2, Fig. <a href="#i_257">81</a>), which arises from the
+lateral parts of the lumbar vertebræ (<i>psoas</i>) and from the iliac
+fossa (<i>iliacus</i>), passes<span class="pagenum" id="Page_264">[264]</span> beneath Poupart’s ligament (page 199),
+and after traversing Scarpa’s triangle is inserted into the lesser
+trochanter of the femur. This muscle is not visible superficially
+except just below and internal to the anterior superior iliac spine,
+where it forms a slight bulging beneath the skin.</p>
+
+<p>The inner part of the floor of Scarpa’s triangle is formed by the
+<i>adductor longus</i>, triangular in shape (10, Fig. <a href="#i_257">81</a>); arising by a
+narrow tendon from the angle of the pubis, it is inserted, beneath the
+sartorius, into the middle portion of the linea aspera of the femur.</p>
+
+<p>The <i>gracilis</i> is visible throughout its entire length on the
+inner surface of the thigh (9, Fig. <a href="#i_257">81</a>). It forms a long slender fleshy
+band, broader above and narrower below. Arising from the symphysis and
+descending ramus of the pubis, it descends vertically; a little above
+the inner condyle of the femur it is replaced by a narrow tendon (15,
+Fig. <a href="#i_263">82</a>), which sweeps round the condyle, behind the sartorius, and in
+front of the semi-tendinosus, to be inserted into the upper part of the
+inner surface of the shaft of the tibia behind the sartorius and above
+the semi-tendinosus.</p>
+
+<p>Covered by the preceding muscles and placed more deeply, are the
+adductors, brevis and magnus, which fill up the space between the
+gracilis and the femur. The <i>adductor brevis</i> extends from the
+pubis to the upper part of the linea aspera; the <i>adductor magnus</i>
+is a thick, fleshy, triangular muscle which arises from the tuberosity
+and ramus of the ischium, and is inserted into the entire length
+of the linea aspera of the femur, so that its superior fibres are<span class="pagenum" id="Page_265">[265]</span>
+horizontal and its inferior fibres almost vertical in direction; among
+these last the most internal, which arise from the ischial tuberosity,
+form below a distinct tendon, which projects above the inner side of
+the knee-joint and is inserted into a tubercle (the <i>adductor</i>
+tubercle of the femur) placed above the inner condyle of the femur.</p>
+
+  <div class="figcenter" id="i_265" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_265.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 83.</p>
+     <p class="p0 sm"><span class="smcap">Hamstring Muscles.</span> 1, gluteus medius;—2, gluteus
+maximus;—3, vastus externus;—4, biceps (long head)—5, biceps
+(short head)—6, semi-tendinosus;—7, semi-membranosus;—8,
+gracilis;—9, adductor magnus;—10, sartorius;—11, popliteal
+space;—12, gastrocnemius.</p>
+  </div>
+
+<p>The action of all the muscles which we have just studied, except the
+pectineus, is to draw the thigh inwards towards the axis of the body;
+they also bring the knees close to each other, hence they are called
+the adductors of the thigh.</p>
+
+<p>IV. <i>The back of the thigh.</i> The <i>posterior</i> muscles of the
+thigh (<i>hamstring muscles</i>).—These muscles, three in number,
+arise from the tuberosity of the ischium, and thus their origins
+are hidden beneath the gluteus maximus. They emerge below the lower
+border of that muscle and descend vertically; above the posterior
+surface of the knee (or ham) they divide into two masses, one, the
+external, formed by a single muscle, the <i>biceps femoris</i>, the
+other internal, formed by two muscles placed one on the other, the
+<i>semi-tendinosus</i> and the <i>semi-membranosus</i>.</p>
+
+<p><span class="pagenum" id="Page_266">[266]</span></p>
+
+<p>The <i>biceps femoris</i> (4, Fig. <a href="#i_265">83</a>) is so called because, like the
+biceps in the arm, it is formed above by two heads, a <i>long</i> head
+which arises from the tuberosity of the ischium, and a <i>short</i>
+head, more deeply placed, which arises from the linea aspera of the
+femur. These two heads unite in a stout tendon (12, Fig. <a href="#i_263">82</a>) which the
+muscular fibres accompany for the greater part of its length, and which
+is directed downwards on the outer side of the knee, to be inserted
+into the summit of the superior extremity of the head of the fibula.
+This muscle flexes the leg on the thigh, and when it accomplishes this
+action its tendon becomes very prominent, forming the outer boundary of
+the region of the ham or popliteal space.</p>
+
+<p>The <i>semi-tendinosus</i> (13, Fig. <a href="#i_263">82</a>; 6, Fig. <a href="#i_265">83</a>), visible
+throughout its entire extent (except at its origin, which is hidden
+beneath the gluteus maximus), has been so called because in a great
+part of its length, almost equal to its lower half, it is represented
+only by its tendon. It arises above from the ischium, and descends
+parallel to the long head of the biceps, to the inner side of which
+it is situated; towards the junction of the middle with the lower
+third of the posterior surface of the thigh, its fleshy belly becomes
+narrower, and is replaced by a long, thin tendon (13, Fig. <a href="#i_263">82</a>) which
+inclines inwards, and passes behind the internal condyle of the femur,
+describing a slight curve with its concavity forwards behind the
+tendons of the sartorius and gracilis. With them (pages 258 and 264)
+it is inserted into the upper part of the internal surface of the
+shaft of the tibia (24, Fig. <a href="#i_275">86</a>). This muscle flexes the leg, and in
+this<span class="pagenum" id="Page_267">[267]</span> movement the prominence of its tendon starts out as the internal
+boundary of the region of the ham.</p>
+
+<p>The <i>semi-membranosus</i> is broader than the semi-tendinosus (7,
+Fig. <a href="#i_265">83</a>). It is situated beneath it and projects beyond it on both
+sides. It is so called because its upper half is formed by a broad
+membranous tendon arising from the tuberosity of the ischium. The
+muscular fibres commence below the middle of the thigh and form a large
+fleshy belly, thick, broad, and short, which passes into a strong
+tendon (14, Fig. <a href="#i_263">82</a>) inserted mainly into the posterior surface of the
+internal tuberosity of the tibia.</p>
+
+<p>The fleshy belly of this muscle projects beyond the tendon of the
+semi-tendinosus on each side, and reaches to the middle line of the
+posterior surface of the thigh and knee, forming a large muscular
+prominence. When the leg is flexed on the thigh, the tendons of
+the biceps and semi-tendinosus become prominent, bounding a deep
+pit (the ham or popliteal space) corresponding to the upper part
+of the posterior surface of the knee, and the fleshy part of the
+semi-membranosus remains hidden in the bottom of this pit; but
+when the leg is extended on the thigh there is no longer a hollow,
+but the posterior surface of the knee presents, on the contrary, a
+prominent form, produced in the upper part by the fleshy mass of the
+semi-membranosus, and in the lower part by the muscles of the calf, to
+be described in the next chapter.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_268">[268]</span></p>
+
+<h2>CHAPTER XXIII.<br>
+<span class="subhed">MUSCLES OF THE LEG AND FOOT.</span></h2></div>
+
+<div class="blockquot">
+
+<p class="hangingindent">General arrangement of the muscles with regard to the
+skeleton.—Anterior muscles of the leg (<i>tibialis anticus</i>
+and <i>extensors</i>).—External or <i>peroneal</i> muscles;
+relations of the peroneus longus with the sole of the
+foot; its influence on the form of the foot.—Posterior
+muscles; <i>gastrocnemius</i> (details of its composition
+and form). <i>Soleus</i> muscle, <i>plantaris</i>, <i>tendo
+Achillis</i>.—Muscles of the foot; 1st, dorsum of foot
+(<i>extensor brevis</i> muscle); 2nd, muscles of the sole of the
+foot.</p>
+</div>
+
+
+<p><i>Muscles of the leg.</i>—The arrangement of the skeleton of the leg
+(tibia and fibula) is such that we might expect <i>a priori</i> to find
+four muscular masses, one on each of the surfaces of the skeleton,
+but as the internal surface of the tibia is subcutaneous (2, Fig.
+<a href="#i_270">84</a>), is not covered by any muscle, and is overlapped by the anterior
+and posterior fleshy masses, it forms a long flat surface, slightly
+hollowed, extending from the inner side of the knee to the internal
+malleolus. The leg, therefore, presents for our study only three groups
+of muscles, occupying respectively the anterior or antero-external, the
+external or peroneal, and the posterior regions of the limb.</p>
+
+<p>I. <i>Anterior muscles</i> (Fig. <a href="#i_270">84</a>).—Arranged in the space which
+separates the fibula from the tibia, the muscles on the front of the
+leg are three in number, called, from within outwards, the <i>tibialis
+anticus</i>, the <i>extensor proprius hallucis</i>, and the <i>extensor
+longus digitorum</i>.</p>
+
+<p><span class="pagenum" id="Page_269">[269]</span></p>
+
+<p>The <i>tibialis anticus</i> (3, Fig. <a href="#i_270">84</a>) arises from the external
+surface of the tibia, and from the deep fascia over it (page 146), and
+descends obliquely downwards and inwards in the form of a prismatic
+or fusiform fleshy mass, of which the lower end gradually narrows, to
+be replaced by a strong tendon in the lower third of the leg. This
+tendon, inclining more and more to the inner side (2, Fig. <a href="#i_275">86</a>), passes
+obliquely over the anterior surface of the lower end of the tibia, in
+front of the internal malleolus. It glides beneath the anterior annular
+ligament of the ankle, and reaches the inner part of the dorsum of the
+foot (3, Fig. <a href="#i_275">86</a>), where it is inserted into the internal cuneiform,
+and the base of the first metatarsal bone. It flexes the foot on the
+leg, and inverts it, since it draws the dorsal surface of the foot
+towards the anterior surface of the leg, while at the same time it
+turns the foot inwards, and slightly raises its inner border. This
+muscle, during contraction, shows externally all the details of its
+shape—in the leg a fleshy mass which slightly overlaps the anterior
+border of the tibia or shin, and in front of the ankle an oblique cord
+marking clearly the direction of the tendon.</p>
+
+<p>The <i>extensor proprius hallucis</i> (5, Fig. <a href="#i_270">84</a>) is concealed at its
+origin between the tibialis anticus and the extensor longus digitorum.
+Only its tendon appears superficially (2, Fig. <a href="#i_272">85</a>) in the lower third
+of the front of the leg, on the outer side of the tendon of the
+tibialis anticus. It passes beneath the annular ligament of the ankle
+and along the inner part of the dorsal surface of the foot (4, Fig.
+<a href="#i_275">86</a>), to be inserted into the base of the terminal phalanx of the great
+toe. When the great toe is forcibly turned up during extension<span class="pagenum" id="Page_270">[270]</span> this
+tendon is clearly shown throughout its entire course. In a normal foot
+this tendon occupies a straight line from the middle of the ankle-joint
+to the great toe, and the inner border of the foot and great toe should
+be parallel to it. In other words, the great toe should be in a line
+with the inner border of the foot (Fig. <a href="#i_151">52</a>, page 151).</p>
+
+  <div class="figcenter" id="i_270" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_270.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 84.</p>
+     <p class="p0 sm"><span class="smcap">Muscles of the Anterior Region of the Leg.</span>—1, tendon
+of the rectus femoris;—2, tibia;—3, the anterior tibial
+muscle;—4, the long extensor of the toes;—5, the proper
+extensor of the great toe;—6, the peroneus tertius;—7 and 8,
+the peroneus longus and brevis;—9, the external head of the
+gastrocnemius;—10, the internal head of the gastrocnemius;—11,
+extensor brevis digitorum;—12, the superior annular ligament of
+the dorsum of the foot.</p>
+  </div>
+
+<p>The <i>extensor longus digitorum</i> (4, Fig. <a href="#i_270">84</a>) arises from the
+external tuberosity of the tibia, on the outer side of the tibialis
+anticus, and from the upper three-fourths of the anterior surface
+of the fibula. It descends vertically, and terminates in a tendon
+divided into slips, which remain associated together (3, Fig. <a href="#i_272">85</a>) to
+pass beneath the anterior annular ligament. Immediately afterwards,
+these slips spread out like a fan (4, Fig. <a href="#i_272">85</a>) in the form of four
+tendons, which pass over the dorsum of the foot to be inserted into
+the second and third phalanges of the four outer toes. Each tendon
+behaves like the corresponding extensor tendon in<span class="pagenum" id="Page_271">[271]</span> the hand. It forms a
+membranous expansion on the dorsum of the first phalanx, joined by the
+tendons of the extensor brevis digitorum, lumbricals, and interossei
+muscles, and completes the capsule of the meta-tarso-phalangeal joint.
+Thereafter each tendon splits into three parts—one central and two
+lateral. The central slip is inserted into the intermediate phalanx,
+and the two lateral slips, reunited, are attached to the base of the
+terminal phalanx. Associated with the extensor longus digitorum is
+the <i>peroneus tertius</i>, an essentially human muscle, which has a
+common origin with the long extensor. Its tendon accompanies those of
+the last-named muscle beneath the annular ligament, and is directed
+outwards on the dorsum of the foot, to be inserted into the base of the
+fifth metatarsal bone. With the tibialis anticus the long extensor of
+the toes and peroneus tertius flex the foot on the leg, while at the
+same time the common extensor extends the toes on the foot. In this
+action it shows the prominence of its fleshy belly especially at the
+middle of the leg, and the tendons on the back of the foot are raised
+up like diverging cords. The peroneus tertius raises the outer border
+of the foot in such movements as skating and dancing, and it is only
+then that its prominence shows beneath the skin. Usually it is but
+little marked.</p>
+
+  <div class="figcenter" id="i_272" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_272.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 85.</p>
+     <p class="p0 sm"><span class="smcap">Muscles of the Leg</span> (external surface).—1, 1, the
+anterior tibial muscle;—2, 2, the tendon of the extensor
+proprius hallucis;—3, 3, the extensor longus digitorum with its
+tendons (4, 5, and 6);—7, the peroneus longus and its tendon
+(8);—9, peroneus brevis and its tendon (10);—11, the external
+head of the gastrocnemius;—12, 12, the soleus;—13, tendo
+Achillis;—14, extensor brevis digitorum;—15, abductor minimi
+digiti;—16, the rectus femoris;—17, 18, vastus externus;—19,
+tendon of the biceps femoris;—20, external lateral ligament of
+the knee.</p>
+  </div>
+
+<p>II. <i>External muscles</i> (Fig. <a href="#i_272">85</a>).—These are two in number,
+placed on the outer side of the fibula, and called the <i>peroneal
+muscles</i>. They are distinguished as the peroneus longus and peroneus
+brevis. They completely cover the outer surface of the fibula, the
+peroneus longus arising from the upper<span class="pagenum" id="Page_272">[272]</span> two-thirds, the peroneus brevis
+from the lower two-thirds of the bone. The peroneus longus is behind
+and above, the peroneus brevis in front and below. Their tendons
+descend together and pass beneath the external annular ligament; that
+of the peroneus brevis lying next the bone and grooving the back of the
+external malleolus. Winding round the malleolus as on a pulley, they
+are directed forwards on to the outer border of the foot. Then only the
+tendons separate from each other, to be inserted into the foot at two
+points diametrically opposite. One (that of the peroneus brevis) is
+directed horizontally forwards, on the outer surface of the foot (10,
+Fig. <a href="#i_272">85</a>), to be inserted into the base or posterior extremity of the
+fifth metatarsal bone; while the other, that of the peroneus longus, is
+directed obliquely forwards and downwards<span class="pagenum" id="Page_273">[273]</span> so as to reach the sole of
+the foot, beneath which it passes, lying in the groove of the cuboid
+bone; it then runs obliquely across the sole of the foot, from the
+outer towards the inner border, deeply hidden by the plantar muscles
+and ligaments, and is finally inserted into the posterior extremity
+of the first metatarsal bone and the under surface of the internal
+cuneiform bone.</p>
+
+<p>These two muscles, but especially the peroneus brevis, extend and turn
+the foot outwards, while at the same time they raise its external
+border; so that their action is the reverse of that of the tibialis
+anticus. But the peroneus longus has another important function which
+explains why the muscle becomes prominent whenever a particular effort
+is demanded of the foot, as, for example, when it is carried forward in
+dancing, or in the act of imparting motion to an object. This muscle,
+owing to the arrangement of its tendon, which passes like the string
+of a bow across the hollow of the sole of the foot, acts by deepening
+this hollow; it therefore raises the plantar arch, marked on the dorsal
+surface by an increase of the curve of the foot.</p>
+
+<p>III. <i>Posterior muscles</i> (Figs. <a href="#i_263">82</a>, <a href="#i_278">87</a>).—The back of the leg
+is thick and fleshy, and is formed by numerous and powerful muscles,
+divided into two groups: the superficial group, which we shall describe
+in detail, and the deep group, for which a few words will be sufficient.</p>
+
+<p>The superficial group is formed by the <i>gastrocnemius</i>,
+<i>plantaris</i>, and <i>soleus</i> muscles.</p>
+
+<p>The <i>gastrocnemius</i> muscle (γαδτήρ, belly; κυήμη, leg) is
+responsible for the surface form of the<span class="pagenum" id="Page_274">[274]</span> prominence of the calf. It
+consists of two large, fleshy masses known as the inner and outer
+heads, which arise respectively from the upper part of the inner and
+outer condyles of the femur on their outer aspect. Overlapped by the
+insertions of the hamstring muscles, the two heads of the gastrocnemius
+form the lower boundaries of the popliteal space. They converge at
+its lower angle to be inserted (separately) into a broad membranous
+tendon, which forms the beginning of the <i>tendo Achillis</i> (6, Fig.
+<a href="#i_278">87</a>). At their origins, each head possesses a tendon which covers its
+superficial surface. At the insertion the tendon passes upwards for a
+considerable distance on their deep surfaces. At its insertion into
+the tendo Achillis, each fleshy head presents a rounded lower border;
+and it is to be particularly noted that the inner head of the muscle
+usually descends to a level lower than that of the outer head.</p>
+
+  <div class="figcenter" id="i_275" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_275.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 86.</p>
+     <p class="p0 sm"><span class="smcap">Muscles of the Leg</span> (internal surface).—1,
+tibialis anticus;—2 and 3, its tendon;—4, tendon of the
+extensor proprius hallucis;—5 and 6, internal head of the
+gastrocnemius;—7, soleus;—8, tendo Achillis;—9, its
+attachment to the os calcis;—10, tendon of the plantaris
+muscle;—11 and 12, tendon of the tibialis posticus;—13 and
+14, tendon of the flexor longus digitorum;—15, tendon of the
+flexor longus hallucis;—16, 16, abductor hallucis;—17, vastus
+internus;—18, 19, 20, sartorius;—21, 22, gracilis;—23,
+semi-membranosus;—24, semi-tendinosus.</p>
+  </div>
+
+<p>This muscle bends the knee and extends the foot on the leg. Through
+the tendo Achillis it acts on the calcaneum or bone of the heel so
+as to raise the heel and cause the living model, if erect, to rise
+on the toes. Now the constitution of the muscle is such that its
+external form is quite different when it is in repose and when it is
+in contraction. Each head of the muscle, as already stated, possesses
+at its origin a membranous tendon, which expands over the outer part
+of the surface, but the inner part of each belly is fleshy. In a state
+of repose the two halves of the muscle unite in the same rounded and
+prominent shape, so that we cannot distinguish the part covered by the
+aponeurotic expansion of tendon<span class="pagenum" id="Page_275">[275]</span> from the part formed by free muscular
+fibres. But when the living model rises on the balls of the toes, or in
+any other movement produced by a powerful contraction of the muscle,
+we see the free fleshy part of each head swell up more strongly than
+the part covered and tied down by the aponeurosis. At that moment,
+therefore, the whole convex form of the calf presents a slight ovoid
+surface on each side, and a long vertical prominence in the middle
+line. This prominence is produced by the mesial muscular parts of the
+two heads of the muscle, which approach each other during contraction,
+and unite their double mass in a single median prominence. Fig. <a href="#i_263">82</a>, by
+the differences in shading, enables us to distinguish the aponeurotic
+from the muscular parts, and to observe the important details of shape
+into the study of which we have entered.<span class="pagenum" id="Page_276">[276]</span> The clear or aponeurotic
+parts correspond to the two flat surfaces already mentioned, and the
+shaded or fleshy parts correspond to the median prominence, with this
+difference, that in the calf in contraction, this median prominence is
+smoother than in Fig. <a href="#i_263">82</a>, the two halves which compose it being merged
+into a single mass, except at the angular space above the point where
+they bound the popliteal space.</p>
+
+<p>We will now return to what we have already said (see page 267) relative
+to the posterior region of the knee, examined in the living model in
+extension of the leg. If the model rises on the balls of the toes it is
+no longer possible to speak of the popliteal space as <i>a hollow</i>
+at the back of the knee. Under these conditions, the prominences
+(already studied) of the biceps, semi-membranosus, and gastrocnemius
+almost join each other, and the plantaris muscle, of which we will
+speak immediately, helps to fill up the space; the region of the
+popliteal space forms in reality a prominence, and the posterior
+surface of the knee is marked in its central portion by a strong
+muscular projection of which it is not possible to understand the cause
+except by an attentive study of the muscles named.</p>
+
+<p>The <i>soleus</i> muscle, so called because its form has been compared
+to that of a <i>sole</i> (Latin—<i>solea</i>), is placed beneath the
+gastrocnemius, which overlaps it, more on the inner (7, Fig. <a href="#i_275">86</a>) than
+on the outer border (12, Fig. <a href="#i_272">85</a>) of the calf. In its action it is
+simple. It only acts on the ankle-joint, as a powerful extensor of
+the foot. Arising from the back of the fibula and from the tibia, its
+fibres are inserted below into the deep surface<span class="pagenum" id="Page_277">[277]</span> of the tendo Achillis
+to within two inches of the heel.</p>
+
+<p>The <i>tendo Achillis</i> is a strong band of fibrous tissue occupying
+the lower part of the back of the leg. Membranous above, where it
+is continued upwards on the deep surface of the bellies of the
+gastrocnemius muscle, it becomes narrower and thicker below as it
+approaches the heel. Broadening out slightly at its lower end, it
+is inserted into the inferior half of the posterior surface of the
+calcaneum, forming the prominence of the heel. In a muscular leg the
+fibres of the soleus may be shown superficially, bulging beyond the
+tendo Achillis at its outer and inner borders, below the outline of the
+gastrocnemius, and more on the outer than on the inner side (5, Fig.
+<a href="#i_263">82</a>, page 263).</p>
+
+<p>The <i>plantaris</i> is a small, insignificant muscle of which the
+fleshy origin (6, Fig. <a href="#i_263">82</a>) is from the outer condyle of the femur,
+under cover of the outer head of the gastrocnemius muscle. Its small
+fleshy belly is succeeded by a long, thin tendon (7, Fig. <a href="#i_263">82</a>), which
+descends obliquely between the gastrocnemius and the soleus to reach
+the inner border of the tendo Achillis, along which it descends (10,
+Fig. <a href="#i_275">86</a>). Sometimes it is united with this tendon early in its course,
+and sometimes it reaches the calcaneum, or it may join the internal
+annular ligament at the ankle.</p>
+
+<p>The deep muscles of the back of the leg are not visible on the model
+except on the inner side above the ankle. Here, on the inner side
+of the tendo Achillis (8, Fig. <a href="#i_263">82</a>), is placed a series of tendons,
+proceeding in the interval between the<span class="pagenum" id="Page_278">[278]</span> internal malleolus and the
+calcaneum to the foot. The muscles are the <i>tibialis posticus</i>,
+the <i>flexor longus digitorum</i>, and the <i>flexor longus
+hallucis</i>. The fleshy bellies of these muscles, deeply hidden
+beneath the superficial muscles, arise from the posterior surface of
+the tibia, from the fibula, and from the interosseous membrane. Their
+tendons descend obliquely over the back of the internal malleolus,
+where those of the tibialis posticus and the common flexor of the toes
+alone are visible (the tendon of the flexor proprius hallucis being
+almost entirely hidden beneath the tendo Achillis). From this they are
+reflected over the internal malleolus and pass into the sole of the
+foot, bound down on the inner side of the ankle by the dense band of
+the <i>internal annular ligament</i>. The tibialis posticus is almost
+immediately inserted by radiating bands into most of the tarsal and
+metatarsal bones (12, Fig. <a href="#i_275">86</a>), and the other two tendons reach the
+toes, where they are inserted in the same manner as we have already
+described for the tendons of the flexor longus pollicis and the deep
+flexor of the fingers in the hand.</p>
+
+  <div class="figcenter" id="i_278" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_278.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 87.</p>
+     <p class="p0 sm"><span class="smcap">The Muscles of the Calf.</span>—1, biceps;—2,
+semi-tendinosus;—3, popliteal space;—4, gastrocnemius;—5,
+5, soleus;—6, tendo Achillis;—7, os calcis;—8, peroneus
+longus;—9, tibialis posticus and flexor longus digitorum.</p>
+  </div>
+
+<p><i><span class="smcap">Muscles of the foot.</span></i>—The muscles of the foot<span class="pagenum" id="Page_279">[279]</span> include
+not only the muscles of the plantar region, corresponding to the palm
+of the hand, but also the tendons on the dorsum of the foot, and a
+special extensor muscle, the <i>extensor brevis digitorum</i>.</p>
+
+<p>The tendons of muscles on the dorsum of the foot have already been
+described (p. 270). The <i>extensor brevis digitorum</i> muscle (11,
+Fig. <a href="#i_270">84</a>, and 14, Fig. <a href="#i_272">85</a>) consists of a short, fleshy belly placed
+obliquely on the dorsum of the foot, and extending from behind inwards
+and forwards. It origin is rounded and attached to the upper surface
+of the calcaneum in the <i>cavity or canal of the tarsus</i> (page
+155), external to the astragalus. From this origin it is directed
+forwards and inwards; becoming broader, it passes beneath the tendons
+of the common extensor and immediately divides into four muscular
+slips, each of which has a tendon attached to it. These tendons pass
+under those of the common extensor, so as to form with them a figure
+with lozenge-shaped spaces, and proceed to the four inner toes to be
+inserted, in the case of the great toe, into the base of the first
+phalanx; uniting, in the case of the second, third, and fourth toes,
+with the expansions of the extensor tendons on the dorsum of the
+phalanges. This muscle aids in the extension of the toes, and by
+its obliquity counteracts the action of the long extensor. When it
+contracts, the portion of the muscle situated on the outer side of
+the tendons of the long extensor become very prominent, not being
+tied down by anything, and this prominence is still clearer because
+behind it is a depression, more or less evident, corresponding to the
+calcaneo-astragaloid cavity of the tarsus.</p>
+
+<p><span class="pagenum" id="Page_280">[280]</span></p>
+
+<p>We will not describe at length the muscles of the sole of the foot
+with regard to form. The foot derives most of its characteristics
+from its bony structure; the muscles of the sole round off by their
+presence the angles of the skeleton and fill up the cavities, but
+do not modify essentially the bony forms. On the other hand, these
+numerous muscles are in general but poorly developed, and they are to
+a large extent united into common masses, which makes it difficult,
+except for the skilled anatomist, to isolate and recognise distinctly
+each fleshy belly. It is therefore useless for an artist to enter
+into a detailed study of these muscles, which reproduce in their
+general arrangement the distribution of the muscles of the hand. We
+will content ourselves, then, by saying that the sole of the foot,
+like the palm of the hand, possesses three muscular masses—1st. An
+internal group (16, Fig. <a href="#i_275">86</a>), belonging to the great toe, formed by
+the <i>abductor hallucis</i>, which arises from the calcaneum, and
+by the <i>flexor brevis</i>, the <i>adductor transversus</i>, and
+<i>adductor obliquus hallucis</i>, which arise from the anterior bones
+of the tarsus and from the metatarsus; 2nd. An external group (15,
+Fig. <a href="#i_275">86</a>), belonging to the little toe, formed by the <i>abductor</i>,
+which arises from the calcaneum, and the <i>flexor brevis</i>, from the
+cuboid; 3rd. Finally, a central mass, formed by the <i>flexor brevis
+digitorum</i>, the <i>long flexor tendons</i>, <i>lumbricals</i>, and
+<i>interossei</i>—which in a sense repeat what we have said regarding
+the muscles of the same name, more easily studied, in the hand.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_281">[281]</span></p>
+
+<h2>CHAPTER XXIV.<br>
+<span class="subhed">MUSCLES OF THE NECK.</span></h2></div>
+
+<div class="blockquot">
+
+<p class="hangingindent">Lateral and anterior regions of the neck.—<i>Sterno-mastoid</i>
+muscles. The anterior triangle; infra-hyoid and supra-hyoid
+regions.—Organs contained in the neck (vertebral column,
+œsophagus, and trachea).—Infra-hyoid muscles—<i>omo-hyoid</i>,
+<i>sterno-hyoid</i>, <i>sterno-thyroid</i>, and
+<i>thyro-hyoid</i>.—Supra-hyoid muscles—<i>digastric</i>,
+<i>stylo-hyoid</i>, and <i>mylo-hyoid</i>.</p>
+</div>
+
+
+<p><i>Muscles of the neck.</i>—We have already, in treating of the
+trapezius, studied the muscular structure and form of the posterior
+region of the neck, and the details have been described of the upper
+part of the side of the neck, and the oblique longitudinal groove
+between the anterior border of the trapezius and the posterior
+border of the sterno-cleido-mastoid (pages 208 and 210). It now
+remains to examine the inferior part of this groove and all the
+anterior region of the neck. This study should begin with that of the
+sterno-cleido-mastoid muscles, which have the most important influence
+on the form of this region, and which by their direction map out on the
+anterior surface of the neck a muscular interval or space in which it
+will be easy to study the deeply placed muscles.</p>
+
+<p>The <i>sterno-cleido-mastoid muscles</i> are two in number, one on
+each side of the neck, extending from the upper limit of the thorax,
+obliquely upwards and backwards, to the base of the skull (19, Fig.
+<a href="#i_275">88</a>). The muscle arises below by two heads—one internal<span class="pagenum" id="Page_282">[282]</span> or sternal,
+which arises by a strong tendon from the front of the first piece of
+the sternum (18, Fig. <a href="#i_197">70</a>, page 197), the other external or clavicular,
+which arises in the form of a thin fleshy band from the inner third of
+the upper surface of the clavicle, above the origin of the clavicular
+portion of the great pectoral muscle (Fig. <a href="#i_194">68</a>, page 194). These
+two heads are directed upwards and backwards, separated at first
+by a narrow triangular space, of which the base corresponds to the
+sterno-clavicular joint (Fig. <a href="#i_194">68</a>); they then unite to form a single
+muscle, broad and thick, which ascends obliquely towards the skull,
+passing behind the angle of the lower jaw and the ear to be inserted
+into the surface of the mastoid process of the temporal bone and the
+superior curved line of the occipital bone (16, Fig. <a href="#i_207">73</a>).</p>
+
+<p>This muscle, being inserted into the skull at a point which is situated
+behind the axis of the movements of flexion and extension of the head,
+acts by extending the head on the neck, but to this movement, usually
+little marked, it adds the power of flexing the neck on the trunk. When
+both these muscles contract at the same time, they produce extension of
+the head on the neck and flexion of the neck on the thorax; therefore
+we see both clearly marked beneath the skin in a person lying down
+who raises his head (by flexion of the neck). When one muscle only
+contracts, it turns the face to the opposite side; therefore in the
+living model whose face is turned to the right the face turns to this
+side by the contraction of the left sterno-cleido-mastoid muscle, of
+which the prominence is well shown beneath the<span class="pagenum" id="Page_283">[283]</span> skin as a broad band,
+passing from the sternum to the mastoid process of the temporal bone.
+There are various attitudes in which this prominence is particularly
+remarkable, as when we carry the head quickly to one side to answer a
+question or give an order; or in the act of listening intently, when
+we concentrate our attention to one side and extend the head a little,
+turning the region of the ear upwards and forwards, an attitude in
+which the sterno-mastoid becomes particularly prominent beneath the
+skin of the neck.</p>
+
+<p>From their insertions and direction we see that these two muscles
+are very close to each other below and wide apart above. Stretching
+diagonally across the side of the neck, each muscle forms the interval
+between two triangular spaces—the <i>posterior triangle</i> behind,
+bounded by the sterno-mastoid, trapezius, and the clavicle (below); and
+the <i>anterior triangle</i> in front, bounded by the sterno-mastoid,
+the middle line of the neck in front, and the lower jaw above. The
+anterior triangles of the two sides comprise together the space between
+the two sterno-cleido-mastoid muscles. This space is in the form of a
+triangle, with its apex below, corresponding to the episternal notch,
+and its base above, formed by the whole breadth of the lower jaw.
+This triangle is the anterior region of the neck, divided into two
+parts by the presence of the hyoid bone—a small bone without direct
+connection with the rest of the skeleton, and placed transversely above
+the prominence of the larynx (23, Fig. <a href="#i_285">88</a>). The lower part forms a
+vertical plane, oblique downwards and backwards,<span class="pagenum" id="Page_284">[284]</span> and sinking behind
+the sternum; this is the infra-hyoid region, containing the infra-hyoid
+muscles. The upper part of the area forms a plane approaching more or
+less the horizontal, proceeding from the hyoid bone to the chin and the
+circumference of the lower jaw; this is the supra-hyoid region, or that
+of the chin, containing the supra-hyoid muscles.</p>
+
+<p>Before entering further into the description of these regions we
+must point out the presence of several organs which, placed in front
+of the vertebral column, project forwards in the space between the
+sterno-mastoid muscles. In the middle line of the neck, the region
+above the hyoid bone corresponds to the floor of the mouth, in which
+the tongue lies, having on each side large salivary glands partly
+concealed by the lower jaw; below the depression corresponding to the
+hyoid bone appear the cartilages of the larynx—the thyroid (pomum
+Adami), projecting forwards, and more marked in the male than in the
+female, and the cricoid cartilage, to which the windpipe or trachea is
+attached. Separating the tongue and larynx from the vertebral column
+is the cavity of the pharynx, which is continuous below the cricoid
+cartilage, with the gullet or œsophagus, situated behind the windpipe
+or trachea. The œsophagus is soft and fleshy, with a cavity effaced
+when empty. The <i>trachea</i>, which on account of its functions is
+always open, is formed of incomplete cartilaginous rings, which give it
+an almost cylindrical form and render it prominent below in the middle
+line of the neck. Crossing the upper part of the trachea is the median
+part of a gland known as<span class="pagenum" id="Page_285">[285]</span> the <i>thyroid body</i>, which in some cases
+(especially in the female) may form a slight rounded projection in the
+infra-hyoid region of the neck.</p>
+
+  <div class="figcenter" id="i_285" style="max-width: 321px">
+     <img
+    class="p2"   
+    src="images/i_285.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 88.</p>
+     <p class="p0 sm"><span class="smcap">Muscles of the Neck and Face.</span>—1, frontal;—2,
+occipital;—3, aponeurosis of the occipito-frontalis;—4,
+temporal;—6, orbicularis palpebrarum;—7, levator labii
+superioris et alæ nasi;—8, dilator naris anterior and
+posterior;—9, compressor naris;—9′, pyramidalis nasi;—10,
+zygomaticus minor;—11, zygomaticus major;—12, masseter;—13,
+levator anguli oris;—14, levator labii superioris;—15,
+orbicularis oris;—16, buccinator;—16′, depressor anguli
+oris, or triangularis oris;—17, depressor labii inferioris,
+or quadratus menti;—19, sterno-cleido-mastoid;—20,
+trapezius;—21, digastric and stylo-hyoid;—22, anterior belly
+of the digastric;—24, omo-hyoid;—25, sterno-hyoid;—26,
+thyro-hyoid;—27, mylo-hyoid;—28, 29, splenius.</p>
+  </div>
+
+<p>The <i>infra-hyoid muscles</i> ascend from the back of the sternum,
+inside the thorax, towards the lower<span class="pagenum" id="Page_286">[286]</span> border of the hyoid bone. They
+are four in number—two superficial (the omo-hyoid and sterno-hyoid)
+and two deep (the sterno-thyroid and thyro-hyoid).</p>
+
+<p>The <i>omo-hyoid</i> (24, Fig. <a href="#i_285">88</a>; 17, 18, Fig. <a href="#i_288">89</a>) is a small muscle,
+long and slender, with a very remarkable course. It consists of two
+fleshy bellies with an intermediate tendon. It arises from the upper
+border of the scapula near the root of the coracoid process, and is
+directed at first obliquely forwards and inwards behind the clavicle;
+after crossing the posterior triangle it turns on itself, and is
+directed upwards beneath the sterno-mastoid and through the anterior
+triangle to be inserted into the lateral part of the lower border of
+the hyoid bone. This muscle, covered at first by the trapezius and
+then by the sterno-mastoid, is thus visible on the model in only two
+parts of its course—in front of the sterno-mastoid, where its anterior
+belly appears over the trachea, and again in the posterior triangle,
+where its posterior belly occupies the lower portion of the groove
+which separates the trapezius from the sterno-mastoid. Although deeply
+placed, this muscle becomes visible beneath the skin, for it is brought
+into sharp relief during certain actions. Evidently, from its slender
+form, we cannot expect it to be an important elevator of the scapula;
+but it serves to depress the hyoid bone. The most important function
+of the muscle is by its contraction, especially during spasmodic
+efforts in respiration, as in the strong inspiration in sighing or
+sobbing; in such cases it prevents the skin and loose aponeurotic
+tissue from being too strongly depressed in the supra-clavicular<span class="pagenum" id="Page_287">[287]</span> fossa
+by atmospheric pressure. Therefore, if the neck is thin and the fossa
+well marked, as in an aged female, during the movements of sobbing or
+abrupt respiration a cord corresponding to the posterior belly of the
+omo-hyoid muscle may be clearly seen in the supra-clavicular fossa.</p>
+
+<p>The <i>sterno-hyoid</i> (25, Fig, <a href="#i_285">88</a>; 14, Fig. <a href="#i_288">89</a>) forms a long, thin,
+fleshy band, extending from the back of the sternum and clavicle
+upwards to the lower border of the hyoid bone. Both these muscles are
+contiguous to each other by their internal borders above, but below, at
+the deep median fossa corresponding to the episternal notch, they are
+separated by a narrow angular space, in which appear the trachea and
+the inner border of the sterno-thyroid muscle.</p>
+
+<p>The two deep muscles of this region (the sterno-thyroid and
+thyro-hyoid) are continuous with one another. They lie beneath the
+sterno-hyoid and omo-hyoid muscles, and cover the trachea and larynx
+in the front of the neck. The <i>sterno-thyroid</i> muscle arises from
+the posterior part of the first piece of the sternum, and ascends
+vertically beneath the sterno-hyoid. It appears at the inner border
+of the sterno-hyoid at the lower part of the neck on each side of the
+middle line (Fig. <a href="#i_194">68</a>); reaching the thyroid cartilage, it is inserted
+into an oblique line on its external surface. The thyro-hyoid muscle
+arising from this oblique line on the thyroid cartilage ascends to be
+inserted into the hyoid bone.</p>
+
+  <div class="figcenter" id="i_288" style="max-width: 366px">
+     <img
+    class="p2"   
+    src="images/i_288.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 89.</p>
+     <p class="p0 sm"><span class="smcap">The Muscles of the Neck.</span>—1, digastric (posterior
+belly);—2, digastric (anterior belly);—3, hyoid bone;—4,
+stylo-hyoid;—5, mylo-hyoid;—6, genio-hyoid;—7,
+stylo-glossus;—8, hyo-glossus;—9, internal pterygoid;—10,
+stylo-pharyngeus;—11, sterno-cleido-mastoid;—12,
+sterno-cleido-mastoid (sternal head);—13, sterno-cleido-mastoid
+(clavicular head);—14, sterno-hyoid;—15, sterno-thyroid;—16,
+thyro-hyoid;—17, omo-hyoid (anterior belly);—18, omo-hyoid
+(posterior belly);—19, trapezius;—20, clavicle;—21, scalenus
+posticus.</p>
+  </div>
+
+<p>The <i>supra-hyoid muscles</i> proceed from the hyoid bone to the base
+of the skull and lower jaw, and by their contraction elevate this bone,
+as can be easily<span class="pagenum" id="Page_288">[288]</span> observed in those who bring into action the pharynx
+or larynx, as in the act of singing or swallowing. The first of these
+supra-hyoid muscles is the <i>digastric muscle</i>, composed of two
+fleshy bellies connected together by an intermediate tendon (1, 2,
+Fig. <a href="#i_288">89</a>). The <i>posterior belly</i> connects the hyoid bone with the
+under-surface of the mastoid process; the anterior belly connects the
+hyoid bone to the lower border of the lower jaw near the chin. Next
+come two other muscles one behind, lying alongside the posterior belly
+of the digastric, and called the <i>stylo-hyoid</i> (4, Fig. <a href="#i_288">89</a>), and
+another in front, called the <i>mylo-hyoid</i><span class="pagenum" id="Page_289">[289]</span> (5, Fig. <a href="#i_288">89</a>); this
+muscle lies underneath the anterior belly, and extends between the
+hyoid bone and the deep surface of the body of the lower jaw. It thus
+forms a partition closing in the floor of the mouth on each side of the
+tongue.</p>
+
+<p>The <i>digastric</i> muscle arises from the under-surface of the
+mastoid process of the temporal bone. From this origin its fusiform
+posterior belly descends obliquely downwards and forwards, and near the
+hyoid bone is replaced by a round tendon. This tendon is attached by
+a fibrous pulley to the hyoid bone, and, taking its fixed point here,
+it turns abruptly, so as to be directed obliquely upwards and forwards
+towards the chin; at the same time this tendon is soon replaced by
+the anterior belly, also fusiform, which is inserted on the posterior
+surface of the symphysis of the chin, into a small depression called
+the digastric fossa. We see that this muscle, with its two bellies, is
+admirably arranged to raise the hyoid bone, and consequently the whole
+of the larynx; for the anterior belly carries the hyoid bone upwards
+and forwards, the other upwards and backwards, and if the two contract
+at the same time they will raise the hyoid bone directly upwards.</p>
+
+<p>The <i>stylo-hyoid</i> is a small muscular fasciculus which accompanies
+the posterior belly of the digastric (21, Fig. <a href="#i_285">88</a>). Arising from the
+styloid process of the temporal bone, this muscle passes downwards and
+forwards beneath the posterior belly of the digastric, with which it
+is closely connected; at the level of the hyoid bone the tendon of the
+digastric pierces the stylo-hyoid,<span class="pagenum" id="Page_290">[290]</span> and the latter terminates by an
+aponeurotic slip which is inserted into the lateral part of the hyoid
+bone. On the model the stylo-hyoid and digastric are united in one
+cylindrical bundle (Fig. <a href="#i_285">88</a>).</p>
+
+<p>The <i>mylo-hyoid</i> muscle (27, Fig. <a href="#i_285">88</a>) forms the floor of the
+cavity of the mouth. It constitutes a quadrilateral fleshy plane,
+attached by its upper border to the inner surface of the body of the
+lower jaw in a prominent oblique line; by its inferior border it is
+inserted into the hyoid bone. Above the hyoid bone the mylo-hyoid
+muscles are also inserted in the middle line into a fibrous raphe, so
+that the two muscles, that of the right and left side, form practically
+a single layer constituting the floor of the mouth. This muscle is
+covered on its deep surface by the mucous membrane of the mouth and
+by the fleshy fibres of muscles which are not visible externally, and
+which, arising from the small tubercles developed on the posterior
+surface of the symphysis of the chin (<i>genial tubercles</i>), are
+inserted either into the hyoid bone (<i>genio-hyoid</i>) (6, Fig. <a href="#i_288">89</a>)
+or into the tongue (<i>genio-hyo-glossus</i>). The mylo-hyoid muscles,
+like the previous muscles, assist in raising the hyoid bone and larynx;
+it is to be noted, too, that the supra-hyoid muscles also act in
+depressing the lower jaw and opening the mouth.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_291">[291]</span></p>
+
+<h2>CHAPTER XXV.<br>
+<span class="subhed">MUSCLES OF THE HEAD.</span></h2></div>
+
+<div class="blockquot">
+
+<p class="hangingindent">1st. Muscles of <i>mastication</i>; <i>masseter</i>, its
+form, its share in the physiognomy (character of firmness, of
+violence); <i>temporal muscle</i>. 2nd. Muscles of expression;
+nature and special mechanism of the muscles of the <i>skin</i>;
+object of their study (expression of actual passion, momentary
+and not characteristic of the subject).—History of the
+question.—Leonardo da Vinci, Le Brun, Camper, Charles Bell,
+Lavater, Sue, Humbert de Superville.—Particular interest of
+the drawings given by Humbert de Superville (“Unknown Signs of
+Art”).—Duchenne of Boulogne and the experimental method applied
+to the study of physiognomy.—Darwin (physiognomy from the
+philosophical point of view, and evolution).</p>
+</div>
+
+
+<p>The muscles of the head with few exceptions occupy the anterior region
+of the head and more particularly the <i>face</i>. They are divided
+into two very distinct classes—1st, the muscles which serve for
+<i>mastication</i> and move the lower jaw; and 2nd, the muscles which,
+under the influence of emotion, modify the traits of the countenance
+and serve for the expression of the emotions. We call these the
+<i>muscles of expression</i>.</p>
+
+<p>The muscles of mastication present the general arrangement that we have
+already met with in the various muscles of the trunk and limbs. They
+are attached to the bones, and they have fleshy bellies, more or less
+thick, which swell up in contraction, and are marked by prominences,
+just as the contraction of the biceps is shown by the prominence<span class="pagenum" id="Page_292">[292]</span> it
+produces on the anterior surface of the arm. The muscles of expression,
+on the contrary, present a different type. These are muscles of the
+<i>skin</i>, which move the skin and not the parts of the skeleton;
+therefore their fleshy parts are in general very slender, and their
+contraction is not marked by any local swelling corresponding to the
+fleshy body, but only by change in place and form of the folds and
+membranous structures of the face (eyelids, lips, etc.). We will first
+study the muscles of mastication.</p>
+
+<p><i>Muscles of mastication.</i>—The muscles which move the lower jaw
+are inserted into the ramus and angle of the bone. Those on the inner
+side of the jaw are the deeply placed <i>pterygoid</i> muscles (so
+called because they arise from the pterygoid process of the sphenoid
+bone). We need not dwell on these muscles here, for they are deeply
+hidden in the zygomatic fossa of the head, and are not visible in any
+part on the surface. Those on the outer side are inserted either into
+the ramus and angle of the bone (masseter muscle) or into the coronoid
+process (temporal muscle).</p>
+
+<p>The <i>masseter muscle</i> is a quadrilateral fleshy mass (12, Fig. <a href="#i_285">88</a>)
+of which the upper attachment arises from the zygomatic arch (Fig. <a href="#i_165">56</a>),
+and the lower attachment is inserted into the ramus and angle of the
+jaw. The anterior border of this muscle is thick, and in thin subjects
+forms a prominence, in front of which the cheeks are sunk so as to
+produce a more or less marked depression. In contraction the masseter
+raises the lower jaw and brings it into contact with the upper, against
+which it presses strongly. It<span class="pagenum" id="Page_293">[293]</span> would be superfluous to dwell here on
+the part this muscle plays in mastication. It is more important to
+remark that during violent emotions, or even when we accomplish a
+powerful effort, we involuntarily clench the jaws. Contracting the
+masseter, therefore, in anger, menace, and in the strong expression
+which we characterise commonly by saying that the subject grinds
+his teeth, we see the masseter shown in the form of a quadrilateral
+prominence on the side of the face. Therefore the accentuation of
+the form of the masseter contributes to give to the physiognomy an
+energetic expression, and generally that of brute force.</p>
+
+<p>The <i>temporal muscle</i> (4, Fig. <a href="#i_285">88</a>) occupies the entire extent of
+the temporal fossa of the skull (Fig. <a href="#i_165">56</a>); it arises from the bones
+that form that fossa and from an aponeurosis which, arising from the
+borders of the fossa, is attached to the upper border of the zygomatic
+arch, so as to form a species of cover (<i>temporal fascia</i>) to the
+fossa in question. From these multiple points of origin the fleshy
+fibres converge below and form a strong tendon which embraces the
+coronoid process of the inferior maxillary bone (25, Fig. <a href="#i_165">56</a>), into
+which it is inserted. This muscle raises the lower jaw, but as it is
+shut up, so to speak, in a close space (temporal fossa and aponeurotic
+cover) it does not show during its contraction a remarkable prominence
+in the temporal region; nevertheless, in a person performing the
+movements of mastication we see the skin of the temple, above the
+zygomatic arch, slightly raised in a series of rhythmical movements;
+these movements alone show externally the contractions of this muscle
+during mastication.</p>
+
+<p><span class="pagenum" id="Page_294">[294]</span></p>
+
+<p><i>Muscles of expression.</i>—From what we have already said
+respecting the peculiar arrangement of these muscles of the skin, it
+is easy to understand that their study must be undertaken in a totally
+different manner from that of the muscles of the skeleton. We do not
+seek so much to define the form of the fleshy masses as to trace the
+direction along which each muscle exercises traction on the skin.
+Given the bony or cutaneous attachments of the muscle, we must observe
+the direction in which it acts, and so define the form of the folds
+or wrinkles which it causes on the skin, and ascertain what facial
+expression is acquired by these changes. Before we enter into these
+details, it is necessary to glance rapidly at the history of this
+particular question of human physiognomy, and then to consider the
+method by which its study should be undertaken.</p>
+
+<p>First we must remark that we study here, with regard to the muscles
+of the face, <i>physiognomy in a state of action</i>—namely, the
+characters that affect the features at a given moment, under the
+influence of a passionate movement which causes (it may be) the
+involuntary contraction of one of the numerous muscles of the skin.
+Indeed, we may almost assert that the muscles of the face might
+be given names associated with mental states—<i>attention</i>,
+<i>pain</i>, <i>menace</i>, <i>laughter</i>, <i>sorrow</i>,
+<i>contempt</i>, <i>disgust</i>, &amp;c. But we cannot pretend to study
+physiognomy in a state of repose, or to learn by the normal and
+permanent accentuation of certain of these traits the character of the
+subject and the passions that most frequently disturb him.</p>
+
+<p>Doubtless, these two studies have numerous points<span class="pagenum" id="Page_295">[295]</span> in common; it is
+easy to admit that, in a subject who is governed by one prevailing or
+overpowering emotion, such as suspicion, grief, or pain, the permanent
+or frequently repeated contraction of the muscles which correspond to
+these emotions can definitely mould the character of the face, so as to
+leave imprinted on it in a permanent form the sentiments that govern
+the mind.</p>
+
+<p>But this analysis of the character of a subject is a very delicate
+study, always very uncertain, and admitting of philosophical
+developments which would carry us far away from the domain of anatomy.
+On the other hand, the determination of characteristic expressions
+impressed upon the face by the contraction of this or that muscle has,
+from the researches of Duchenne (of Boulogne), become a study which
+presents all the precision and certainty that we can claim from facts
+strictly deduced from anatomy.</p>
+
+<p>Before the researches of Duchenne, the majority of books written on
+expression dealt almost entirely with <i>physiognomy</i>, or the means
+of recognising the character by the study of the habitual state of the
+traits of the countenance. We shall, in the first place, mention the
+works of Le Brun, Camper, Lavater, C. Bell, Humbert de Superville, and
+Sue, and then we shall refer to the investigations of Duchenne and
+Darwin.</p>
+
+<p>Long ago, in the drawings of Leonardo da Vinci, we find some valuable
+indications of the state of the face and neck in the expression of
+the emotions. This great master, for example, clearly perceived the
+part that the platysma muscle of the neck takes in the expression
+of violent passions, and portrayed<span class="pagenum" id="Page_296">[296]</span> the transverse folds which then
+mark it beneath the chin. Le Brun, however, was the first to arrange
+studies of this character into a doctrinal series. The publications in
+which his views on this subject have been preserved are numerous.<a id="FNanchor_7" href="#Footnote_7" class="fnanchor">[7]</a>
+The artist will find there a number of interesting observations,
+curious comparisons, and ingenious explanations. Le Brun occupied
+himself principally with the resemblance of certain types of human
+physiognomies to the heads of animals; in short, he studied physiognomy
+in relation to character.</p>
+
+<p>Camper, whose works we have already quoted respecting the facial angle
+(page 181), was an anatomist and an artist. He analysed the action of
+the facial muscles, and it was he who first laid down this general
+rule—viz. that the contraction of each muscle of the face produced in
+the skin one or more folds, of which the direction is always at right
+angles to that of the muscle, a precept that we shall find to be true
+with regard to almost every muscle of the face, and especially for the
+frontalis, the great zygomatic, &amp;c. Besides the exact observations that
+the artist will meet in the works of Camper, he will find in addition
+an interesting historical account of the question.</p>
+
+<p>An English anatomist, Sir Charles Bell, celebrated for his studies
+of the nervous system, also analysed the expressions of the face.<a id="FNanchor_8" href="#Footnote_8" class="fnanchor">[8]</a>
+But though his work<span class="pagenum" id="Page_297">[297]</span> affords picturesque descriptions and admirable
+illustrations, it is more interesting to the anatomist than the artist.</p>
+
+<p>The title of the work of Lavater (<i>The Art of Knowing Man by his
+Countenance</i>)<a id="FNanchor_9" href="#Footnote_9" class="fnanchor">[9]</a> indicates the object sought by the author. We find
+in this work good illustrations, and curious observations especially
+applicable to the study of physiognomy, but frequently without order,
+without method, and accompanied by dissertations on whimsical subjects,
+such as the chapters devoted to <i>imaginations</i> and <i>envies</i>,
+to <i>warts</i> and <i>beards</i>, and to <i>lines of animality</i>, &amp;c.</p>
+
+<p>In order to have an idea of the manner in which, at this epoch, authors
+attempted the study of physiognomy, making this delicate analysis a
+pure affair of sentiment, it is sufficient to mention the work of Sue
+(<i>Physionomie des Corps Vivants, considéré depuis l’Homme jusqu’à la
+Plante.</i> Paris, 1797.) In the middle of a long affected treatise
+on physiognomy and its relation to the passions, this, for example,
+is how he expresses himself concerning the mouth:—“A mouth delicate
+and pure is perhaps one of the best recommendations. The beauty of the
+portal proclaims the dignity of that which passes through. Here also
+is the voice, the interpreter of the heart and mind, the expression
+of truth, friendship, and the most tender sentiments.” With regard to
+the incessant comparison of human physiognomy with that of animals,
+the author stops at nothing in this singular course, and speaks
+dogmatically on the physiognomy of fishes, serpents, grasshoppers, and<span class="pagenum" id="Page_298">[298]</span>
+intestinal worms (!), as well as that of man. “Many fishes,” said he,
+“are wanting in that which gives a character of amenity, kindness, and
+tenderness.” “The intestinal worms have a very decided physiognomy ...
+the character of their physiognomy inspires in man sorrow and awe.”</p>
+
+<p>Amidst the works of a more serious, though still empirical character,
+we must mention in particular one which, although dealing with the
+countenance only in a secondary degree, yet presents several valuable
+observations on this subject. We have endeavoured to utilise these
+investigations in the diagrammatic representation of the action of the
+muscles of the face. We speak of the treatise of Humbert de Superville
+(<i>Des Signes Inconscients de l’Art</i>, 1827). The author gives three
+drawings of the human face, in which the lines represent the eyes, the
+lower boundary of the nose, and the lips. In one of these drawings
+(Fig. <a href="#i_299">90</a>) the lines are all horizontal, in the second (Fig. <a href="#i_299">91</a>) they
+are all inclined downwards and outwards (from the median line), and
+in the third (Fig. <a href="#i_299">92</a>) they are all inclined upwards and outwards.
+The author remarks that the first figure (with the lines horizontal)
+produces an impression of calmness, greatness, and constancy; and
+he adds that in the same way in nature and architecture horizontal
+lines give rise to the idea of calmness, stability, and grandeur: the
+cedar, with its horizontal branches, is of all the trees the one that
+realises this impression in the highest degree. On the contrary, the
+second figure (with the lines directed obliquely downwards) gives
+an impression of sadness, pain, and grief; and the author does not
+fail to<span class="pagenum" id="Page_299">[299]</span> compare the direction of the features of such a countenance
+with the direction of the architectural lines in tombs and funeral
+monuments, and that of the branches of the trees which everywhere are
+planted in preference to others in cemeteries, and whose branches
+always hang obliquely. Lastly, the third figure (with the lines
+obliquely upwards) gives rise to the impression of gaiety, laughter,
+levity, inconstancy; and, to continue the preceding comparison,
+everyone must acknowledge that Chinese architecture, with its lines
+oblique and diverging upwards and outwards, can never—at least, in the
+eyes of a European—produce an impression of grandeur and majesty.</p>
+
+  <div class="figcenter" id="i_299" style="max-width: 400px">
+     <img
+    class="p2"   
+    src="images/i_299.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 90.&emsp;&emsp;&emsp;Fig. 91.&emsp;&emsp;&emsp;Fig. 92.</p>
+     <p class="p0 sm center"><span class="smcap">The Three Figures of Humbert de Superville</span>—(Fig. <a href="#i_299">90</a>,
+calmness; Fig. <a href="#i_299">91</a>, sadness; Fig. <a href="#i_299">92</a>, gaiety).</p>
+  </div>
+
+<p>These figures, and the remarks that de Superville makes afterwards,
+but which we have not emphasised here, are strikingly exact, when
+we consider the features in the state of movement or in a momentary
+expression of emotion. All the muscles which take part in the
+expression of pain, sadness, and contempt help to incline the features
+obliquely downwards and outwards, some by acting on the<span class="pagenum" id="Page_300">[300]</span> outline of the
+eyes, others on that of the mouth, &amp;c. On the contrary, the muscles
+of laughter, raising its angles, draw the mouth obliquely upwards
+and outwards, and—for certain reasons that we will analyse further
+on—seems to give a similar direction to the outline of the eyes. In
+a word, features, starting from the state of repose, represented by
+the first figure of Humbert de Superville (Fig. <a href="#i_299">90</a>), oscillate in two
+opposite directions, either ascending, to express the scale of gaiety
+and laughter (in which the features are oblique upwards and outwards,
+Fig. <a href="#i_299">92</a>), or descending—sadness, pain, and tears (in which the
+features are oblique downwards and outwards, Fig. <a href="#i_299">91</a>). The exactness
+of the drawings furnished by Humbert de Superville for the general
+expression of the physiognomy induces us to try, by similar drawings,
+to represent the action of each muscle separately. Knowing the action
+of a muscle, and knowing from the photographs of Duchenne the direction
+that it imparts to a certain feature of the face, either to the line of
+the eyebrows, the opening of the eyelids, the nostrils, or the lips,
+we have indicated by a simple stroke or line these changes, either
+in direction or in the form of one of those lines, and have obtained
+theoretical figures sufficiently expressive to characterise the emotion
+geometrically, so to speak, in the manifestation of which this or that
+muscle is affected. Such are the Figures <a href="#i_317">96</a>, <a href="#i_319">98</a>, <a href="#i_321">100</a>, <a href="#i_325">102</a>, <a href="#i_326">103</a>, <a href="#i_327">104</a>,
+<a href="#i_333">106</a> (page 317 and following), by means of which we will attempt to
+explain the action of each muscle of expression. We may say that these
+drawings, without any pretension,<span class="pagenum" id="Page_301">[301]</span> are, so to speak, the primer of the
+language of physiognomy.</p>
+
+<p>We now arrive at the history of the work of Duchenne, to which we owe
+all that follows. While all his predecessors had been taken up with
+observation, Duchenne introduced the experimental method into the study
+of physiognomy. His process, simple in conception, was very delicate
+in application. His method was to cause the contraction of each
+muscle <i>singly</i>, and that the expression that resulted might be
+appreciated not only at the moment of the experiment, but again at any
+time, and submitted to the judgment of all, he photographed the subject
+at the moment when the muscle was contracted. This last operation was
+easily accomplished, but the excitation of a single muscle was a more
+delicate operation. Everyone knows that by electricity, in placing
+the two electric needles (the two poles of the current) on the course
+of a muscle, we can cause the contraction of the muscle beneath the
+skin. But no subject would lend himself to this experiment. At first
+he tried on the dead body of an executed criminal a short time after
+death; but the muscles of the face lose their excitability two hours
+after death, and then it is only by actual exposure of the muscle and
+direct stimulation that we can obtain contraction by the application of
+electricity. On the other hand, if we attempt it on any living subject,
+we can, it is true, cause a muscle to contract by applying electricity
+over its site; but the electric current, traversing the skin to reach
+the muscle, at the same time that it excites the<span class="pagenum" id="Page_302">[302]</span> motor nerves of the
+muscle, excites also the sensory nerves of the skin and produces acute
+pain. From this fact we see that we produce on the face of the subject,
+not a simple and characteristic expression, but a true grimace, or an
+irregular contraction of all the muscles under the influence of the
+pain.</p>
+
+<p>Duchenne had the good fortune to be able to experiment on a subject in
+whom a particular infirmity rendered impossible the last inconvenience
+we have noted. This was an old pensioner of the hospital who had
+<i>anæsthesia</i> of the face (ἀνα, absence of; αἴσθησις, sensibility),
+in whom the skin of the countenance was insensible to the most painful
+excitation; electricity could be applied to the skin without producing
+any painful reaction, and yet excited the muscles beneath, which had
+perfectly preserved their contractility, and performed their functions
+as in a normal subject. He could, therefore, cause this or that muscle
+to contract alone, and could excite, for example, the action of the
+great zygomatic, giving to the face the expression of laughter,
+without the subject having any idea of what his physiognomy reflected;
+his face, by the action of the electricity, was laughing, while his
+thoughts might be indifferent or fixed on sad recollections; on the
+other hand, for example, by the contraction of the superciliary muscle,
+his countenance might express the most acute pain, while his thoughts
+might be quite indifferent or borne away by gay and pleasant ideas. In
+a word, Duchenne was able to realise, under the most precise conditions
+of experiment, an exact study of the uses of the muscles of expression.</p>
+
+<p><span class="pagenum" id="Page_303">[303]</span></p>
+
+<p>The work in which Duchenne has given the result of his labours is
+remarkable particularly for the magnificent atlas of photographs that
+accompany it, and which have been obtained by the above process. From
+these photographs have been reproduced as exactly as possible the
+several figures that accompany the descriptions which follow (Figs.
+<a href="#i_316">95</a>, <a href="#i_318">97</a>, <a href="#i_320">99</a>, <a href="#i_322">101</a>, page 316 and following). We cannot enter here into
+a complete statement of the results obtained by Duchenne, but we
+will seek at least to show the serious and scientific value of these
+studies, and to inspire the student to refer to the original work.</p>
+
+<p>These studies have for the artist this important result—namely, to
+prove to him that frequently the contraction of a single muscle is
+sufficient to express an emotion, and that it is not necessary to
+change all the features in order to give to the face the stamp of pain,
+attention, menace, contempt, disgust, &amp;c., each of these sentiments
+being expressed by a slight modification, either of the eye alone, or
+of the lip alone. Each expression has, so to speak, its own exact,
+precise, and separate mark, produced by a single local modification;
+but this local modification seems to be reflected throughout the
+physiognomy, and therefore, from unaided observation, artists had for
+a long time believed that, for example, attention and pain were shown
+by the combined action of a number of facial muscles. Now experiment
+proves that pain may be expressed solely by a muscle which raises and
+wrinkles the brows, and on a face (Fig. <a href="#i_320">99</a>) where this muscle alone is
+contracted (<i>superciliary muscle</i>, page 320) the expression of
+pain is complete. We<span class="pagenum" id="Page_304">[304]</span> naturally believe that the mouth also takes part
+in it, but if we cover the upper part of the countenance, we perceive
+that the lower part of the face is in a state of complete repose.</p>
+
+<p>To bring to a close this history, which is not the least interesting
+part of the subject, we must say that the labours of Duchenne were not
+at first received with great favour in France. Physiologists as well
+as artists showed a certain distrust of a work which pretended to give
+precise rules and scientific laws to a subject about which it had been
+the custom to make fanciful and sentimental comparisons. Few persons
+understood the nature of the reason which forced Duchenne to choose as
+a subject for these experiments a poor man with a physiognomy almost
+imbecile in repose, and they did not consider that if this face was
+old, wrinkled, thin, and vulgar, there was the greater reason to be
+struck with the precision with which the electric excitation enabled
+the most opposite and characteristic expressions to be taken.</p>
+
+<p>As has been too often the fate of scientific discoveries, the work of
+Duchenne was neglected in France, and was not appreciated until it had
+been adopted by a foreign country. It was Darwin who made the results
+of the French physiologist the basis of his own interesting studies.</p>
+
+<p>It is not necessary to recall the extent and repute of the works of
+Darwin on <i>The Origin of Species</i>, on the <i>Evolution of Animals
+and Plants</i>, and on <i>The Descent of Man</i>. What this great
+naturalist has done for the general morphology of plants and animals
+he sought to do for the subject of physiognomy. Seeking<span class="pagenum" id="Page_305">[305]</span> in the
+logical chain of natural facts the cause of all biological phenomena,
+he endeavoured to discover by the attentive study of the movements of
+expression, and through their origin and development, a series of new
+arguments in favour of the theory of evolution. In a word, Darwin, by
+invoking the association of certain useful movements, and comparing the
+functions with the expressions with which they are associated, sought
+to explain why one muscle in particular rather than another is affected
+by the expression of this or that emotion. We cannot here enter further
+into the analysis of this philosophical work. It is sufficient to
+remark (having commended the perusal of it as most interesting to the
+artist<a id="FNanchor_10" href="#Footnote_10" class="fnanchor">[10]</a>) that before we explain anything it is necessary that it
+should be firmly established. Therefore the explanation of the part
+that each muscle takes in the expression must be impossible until the
+fact of the action and the expression associated with the movement of
+the muscle has been scientifically demonstrated. The philosophical work
+of Darwin could not have been undertaken if it had not been preceded by
+the experimental work of Duchenne.</p>
+
+<p>Summarising Darwin’s argument, his thesis may be stated somewhat as
+follows: that every expression or bodily manifestation of emotion has
+a physical basis, and an origin in some <i>useful exercise</i> of the
+particular muscles concerned; that such an action becomes habitual
+in the individual, and is transmitted from father to son, and from
+generation to generation;<span class="pagenum" id="Page_306">[306]</span> and that the actual physical cause is
+transferred to a mental condition, so that an action like knitting the
+brows—primitively for the purpose of actually clearer vision—becomes
+indicative of a mental state in which the emotion is expressed of a
+desire for a clearer mental vision, as when a man is engaged in any
+intellectual problem.</p>
+
+<p>Darwin further enunciated the important principle of <i>Antithesis</i>:
+which means the employment of exactly the opposite expression (it may
+be by the relaxation of muscles, or by the contraction of antagonistic
+muscles), to indicate an opposite or antagonistic attitude of mind.
+Thus joy is expressed by the contraction of a definite series of facial
+muscles; grief or dejection is expressed by the relaxation of these and
+the contraction of opposing muscles. The healthy, alert man holds his
+head erect; the depressed or miserable has a drooping gait.</p>
+
+<p>A third principle enunciated by Darwin as employed in producing
+the expression of emotion is <i>the direct action of the nervous
+system</i>, to a large extent independent of the will, and served
+mainly through the sympathetic nervous system, such as blushing,
+trembling, perspiration, &amp;c.</p>
+
+<p>It is important, as Darwin points out, to bear in mind that emotion is
+expressed not only by facial expression, but by many other agencies as
+well; by the emission of sounds, by the voice in some cases, by the
+rattling of the tail quills in the case of the porcupine, &amp;c.; by the
+inflation of the body, as in the hen who raises up all her feathers
+in maternal anger, or the dog whose hair stands on<span class="pagenum" id="Page_307">[307]</span> end; by gestures,
+rubbing, licking, caresses, kisses; or by the attitude and movements of
+the body, head, or limbs.</p>
+
+<p>In his book each emotion and its corresponding expression is carefully
+analysed, and the physical cause and the particular muscles engaged
+are pointed out. Thus Darwin says, “Weeping is the result of some such
+chain as follows: Children wanting food or suffering in any way, cry
+out loudly as a call to their parents for aid, like the young of most
+animals. Prolonged screaming leads to the gorging of the blood vessels
+of the eyes; and this causes first consciously and then habitually the
+contraction of the muscles round the eyes in order to protect them.”
+The mouth at the same time is opened widely to allow of a more vigorous
+scream. The overflow of tears is a consequence of the closure of the
+eyes.</p>
+
+<p>Again, in regard to the facial expression in laughter, Darwin suggests
+that as the primitive cause of laughter may have been a practical
+joke—or, as De Rochefoucauld put it, there is something pleasing in
+the misfortunes of one’s friends—the expression may be associated with
+the retraction of the angles of the mouth, and the exposure of the
+canine teeth, in preparation for self-defence if the victim of the joke
+should retaliate.</p>
+
+<p>The expression of disdain or disgust in the same way is associated with
+the contraction of muscles of the eye, nose, and mouth, primitively
+from purely physical causes, which have become connected with a mental
+attitude. The head is turned aside, and the eye is half closed to shut
+out an<span class="pagenum" id="Page_308">[308]</span> unpleasant sight; the nostril is raised at the sensation of a
+disagreeable smell, and the lips are curled in disgust at a nasty taste.</p>
+
+<p>There is not space in which to dwell further on these deeply
+interesting questions, for a study of which the reader is referred to
+Darwin’s masterly treatise on the subject.</p>
+
+<p>The figures which illustrate the work of Darwin are in a great measure
+only reproductions of the photographs published by Duchenne about ten
+years previously. However, as we have already mentioned, attention has
+been recalled in France to the works of Duchenne, a more favourable
+judgment has been passed, and justice has been rendered to him who
+had opened the way to the experimental study of physiognomy. In 1874
+the French began to devote, in the course of anatomy in the School of
+Fine Arts, several lectures to the account of what we must call the
+primer or grammar of the expression of physiognomy. Happy in seeing
+his works included in this classical course of instruction, Duchenne,
+whom death carried off a few years later, gave to the School of Fine
+Arts the complete series of large original photographs from which these
+publications are reduced, and this beautiful collection is to-day one
+of the most valuable in the French museum of anatomy (Muséum Hugnier).</p>
+
+<p>Although this account may appear long, it is nevertheless very
+incomplete, being given only with a particular object—that of
+comparing the works of Duchenne with those preceding him. Those of
+Duchenne will be made the basis of the studies which follow. We will
+finish by noting, as interesting<span class="pagenum" id="Page_309">[309]</span> and instructive, the works that treat
+in a more general manner of expression and physiognomy, such as those
+of Lemoine, Gratiolet, and Piderit.<a id="FNanchor_11" href="#Footnote_11" class="fnanchor">[11]</a></p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_310">[310]</span></p>
+
+<h2>CHAPTER XXVI.<br>
+<span class="subhed">MUSCLES OF THE FACE.</span></h2></div>
+
+<div class="blockquot">
+
+<p class="hangingindent">Muscles of the upper part of the face: <i>Occipito-frontalis</i>
+(attention); <i>orbicularis palpebrarum</i> of the eyelids,
+superior <i>orbital</i> portion (reflection); <i>pyramidalis
+nasi</i> (menace); <i>superciliary</i> (<i>corrugator
+supercilii</i>) (pain).—Muscles of the middle region of the
+face: <i>Great zygomatic</i> (laughter); <i>lesser zygomatic</i>
+and <i>levator labii superioris</i> (tenderness, sorrow);
+<i>levator labii superioris alæque nasi</i> (weeping bitterly),
+<i>compressor naris</i> (lewdness).—Muscles of the lower
+region of the face: <i>Orbicularis oris</i>; <i>buccinator</i>;
+<i>depressor anguli oris</i> (contempt); <i>depressor labii
+inferioris</i> (disgust); <i>platysma</i> muscle of the
+neck.—Classification into muscles completely expressive
+and expressive by complement.—Of associations possible and
+impossible with regard to mechanism and with regard to the
+nature of the emotions.—Conclusion.</p>
+</div>
+
+
+<p>The muscles of the face, which are attached to the skin, move and
+alter the shape of its folds and apertures. These different cutaneous
+parts are very complex, but at the same time known to persons who are
+the greatest strangers to anatomy. For them even it is unnecessary to
+describe here the eyebrows, the eyelids, the palpebral fissure, the ala
+or wing of the nose, and the lips. We will only point out, with regard
+to these parts, the significance of their various anatomical names, the
+employment of which will be useful in abridging the descriptions that
+follow.</p>
+
+<p>On the <i>eyebrow</i> we distinguish a broad internal part (towards the
+median axis of the face) called the <i>head</i> of the eyebrow, and
+an external part called the <i>tail</i> of the eyebrow, which becomes
+thinner as it is removed from the middle line.</p>
+
+<p><span class="pagenum" id="Page_311">[311]</span></p>
+
+<p>On each palpebral fissure, at its inner end, is a small perforated
+papilla—the <i>lachrymal papilla</i>—the perforation in which
+is named the <i>punctum lachrymale</i>, carrying the tears from
+the surface of the eye into the nose by special ducts. Each of the
+two extremities of the palpebral fissure bears the name of the
+<i>canthus</i>, or <i>angle</i>. We distinguish, therefore, on the
+eyelids an <i>external canthus</i> or <i>angle</i> characterised by
+its pointed form, and an <i>internal</i> characterised by its rounded
+form, bounding a small oval space called the <i>lachrymal lake</i>,
+at the bottom of which a rose-coloured fleshy tubercle projects (the
+<i>caruncula lachrymalis</i>). External to this is a pale fold, the
+<i>plica semilunaris</i>, a rudiment of the third eyelid (found in
+birds). We also give the name of <i>commissure</i> (or angle) to each
+extremity of the buccal aperture (<i>commissure of the lips</i>). The
+groove extending from the septum of the nose to the centre of the upper
+lip is known as the <i>philtrum</i>.</p>
+
+<p>Lastly, we must note a fold which normally exists in a more or less
+marked degree in every subject, and the changes of which take a great
+part in the expression produced by the various muscles of the cheeks.
+This is the <i>naso-labial fold</i>, so named because, arising from the
+region bounded by the cheek and the side of the nose, it is directed
+obliquely downwards and outwards, passes at a short distance from the
+posterior border of the wing of the nose, and terminates near the
+commissure of the lips. In the subject who served for the experiments
+of Duchenne (Fig. <a href="#i_320">99</a>, page 320) this fold was strongly marked, as it
+generally is in all old people.</p>
+
+<p>The human head and face, the features, and<span class="pagenum" id="Page_312">[312]</span> the muscles which underlie
+the skin have, it is supposed, undergone progressive and retrogressive
+changes in the process of evolution. The cranium has expanded with the
+evolution of the brain, while the face has become smaller and feebler,
+and the teeth have shown distinct signs of degeneration and diminution,
+both in size and number.</p>
+
+<p>Of the soft parts of the face, the apertures of the eyes and mouth
+have increased in mobility and functional power and refinement of
+expression; while the nasal apertures and the ears illustrate a
+retrogression in evolution. The interior of the nasal cavity as well as
+the nostrils presents a simpler or more degenerate type in man than in
+the lower animals, in whom the sense of smell is so much more highly
+developed. The external ear is a good example of a <i>rudimentary
+organ</i>. Its parts have a definite form, and each wrinkle or
+corrugation has a separate name (see Fig. <a href="#i_313">93</a>). It is composed of
+a mass of <i>elastic</i> cartilage (except in the tip or lobule)
+which penetrates into the passage of the ear in a tubular form. This
+cartilaginous <i>pinna</i> is the shrivelled-up remains of the mobile
+funnel-shaped ear of the lower animals; and the <i>tip</i> of the ear
+is represented by an angular projection (Darwin’s tubercle) placed on
+the edge of the rim of the ear (<i>helix</i>).</p>
+
+<p>The lobule is soft, and consists of a mass of fat enclosed in the skin.
+It is usually free from the neck, but in some cases (as, for example,
+in the right ear of the poet Byron) the lobule is attached to the skin
+of the neck, and is not in full relief.<span class="pagenum" id="Page_313">[313]</span> The muscles of the nose and
+ear are also degenerate, and the movements of the nostrils and of the
+ears are only rudimentary.</p>
+
+<p>In the same way the arrangement of the muscles underlying the skin of
+the neck and head presents examples of advance or retrogression when
+compared with the similar muscles of lower animals.</p>
+
+  <div class="figcenter" id="i_313" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_313.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 93.</p>
+     <p class="p0 sm"><span class="smcap">The External Ear.</span>—<span class="allsmcap">H.</span> helix;—<span class="allsmcap">F.H.</span>
+fossa of the helix;—<span class="allsmcap">A.H.</span> anti-helix;—<span class="allsmcap">F.A.H.</span>
+fossa of the anti-helix; <span class="allsmcap">C.</span> concha;—<span class="allsmcap">T.</span>
+tragus;—<span class="allsmcap">A.T.</span> anti-tragus;—<span class="allsmcap">L.</span>
+lobule;—<span class="allsmcap">D.</span> Darwin’s tubercle.</p>
+  </div>
+
+<p>In hairy animals the body is covered all over by a thin layer of muscle
+which underlies the skin, and is called the <i>panniculus carnosus</i>.</p>
+
+<p>In man the body has become almost denuded of hair, except on the head
+and face, and at the same time his capacity of facial expression is
+vastly greater than in one of the lower animals.</p>
+
+<p>The effect of these changes is seen in the condition of the panniculus
+carnosus. It has degenerated over the hairless trunk, and only remains
+normally as the <i>platysma myoides</i> of the neck. But, on the
+other hand, the parts of the panniculus carnosus which have swept
+over the face and have surrounded the apertures of the eye and mouth
+in particular, have become differentiated into the complicated series
+of muscles of expression, rudimentary and<span class="pagenum" id="Page_314">[314]</span> feeble on the scalp and in
+relation to the pinna and the nasal opening, but highly organised in
+relation to the apertures of the eye and mouth.</p>
+
+<p>It is for the most part these highly differentiated muscles which have
+to be dealt with in this chapter in connection with the expression of
+the emotions.</p>
+
+<p>The muscles of expression (Fig. <a href="#i_315">94</a>) are arranged in three series: one
+around the eyes and eyebrows, occupying the upper region of the face;
+the second about the nose; and the third around the aperture of the
+mouth, occupying the middle and especially the lower region of the
+face. The first series includes the <i>occipito-frontalis</i>, the
+<i>corrugator supercilii</i>, and the <i>orbicularis palpebrarum</i>;
+the second includes the <i>pyramidalis nasi</i>, <i>compressor
+naris</i>, and <i>dilator alæ nasi</i>; the third set is most numerous,
+comprising the <i>levator labii superioris alæque nasi</i>, <i>levator
+labii superioris</i>, <i>zygomaticus major</i> and <i>minor</i>, the
+<i>levator anguli oris</i>, the <i>orbicularis oris</i> (to which we
+may add the <i>buccinator</i>), the <i>risorius</i>, <i>depressor
+anguli oris</i>, and <i>depressor labii inferioris</i>. Finally, in the
+neck and extending up to the lower jaw is the <i>platysma myoides</i>,
+which takes a considerable part in certain powerful expressions of the
+face.</p>
+
+  <div class="figcenter" id="i_315" style="max-width: 371px">
+     <img
+    class="p2"   
+    src="images/i_315.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 94.</p>
+     <p class="p0 sm center">(<i>From Cunningham’s “Text Book of Anatomy.”</i>)</p>
+     <p class="p0 sm"><span class="smcap">The Muscles of the Face.</span>—1, frontalis;—2, attrahens
+aurem;—3, epicranial aponeurosis;—4, attolleus aurem;—5,
+occipitalis;—6, retrahens aurem;—7, trapezius;—8,
+parotid gland;—9, sterno-cleido-mastoid;—10, orbicularis
+palpebrarum;—11, pyramidalis nasi;—12, compressor naris;—13,
+levator labii supertoris alæque nasi;—14, levator labii
+superioris;—15, levator anguli oris;—16, depressor alæ
+nasi;—17, zygomaticus major;—18, Stenson’s duct;—19,
+orbicularis oris,—20, risorius;—21, buccinator;—22,
+depressor anguli oris;—23, depressor labii inferioris;—24,
+masseter;—25, platysma myoides.</p>
+  </div>
+
+<p>In the study of these muscles we will enter but little into anatomical
+details, but will content ourselves with pointing out the situation
+of the muscle, its fixed attachments to the bones of the face, its
+direction, and, lastly, the point on the skin where it takes its
+insertion. On the other hand, we must carefully inquire into its
+mechanism and the manner in which its contraction produces alterations
+in the<span class="pagenum" id="Page_315">[315]</span> skin of the face, and the nature and direction of the folds
+which it marks thereon. We must ask ourselves<span class="pagenum" id="Page_316">[316]</span> what expression results
+by the occurrence of these alterations in the face. And, lastly, we
+will endeavour to give a diagram of this expression after the mode of
+representation employed by Humbert de Superville (page 298).</p>
+
+  <div class="figcenter" id="i_316" style="max-width: 300px">
+     <img
+    class="p2"   
+    src="images/i_316.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 95.</p>
+     <p class="p0 sm center smcap">Contraction of the Frontal Muscles</p>
+     <p class="p0 sm center">(expressions of <i>attention</i> and <i>astonishment</i>).</p>
+  </div>
+
+<p class="center p1 smcap lg">A.—Muscles of the upper part of the face (forehead, eyebrows,
+eyelids, and root of nose.)</p>
+
+<p>1st. <i>Occipito-frontalis muscle</i> (muscle of
+<i>attention</i>).—This muscle (1, Fig. <a href="#i_285">88</a>, page 285) (Fig. <a href="#i_315">94</a>)
+consists of an anterior and a posterior belly, connected by an
+intermediate membranous tendon covering the scalp. Its anterior belly
+extends as a fleshy sheet, quadrilateral in form, over each lateral
+half of the forehead. The muscles of each side are continuous with
+one another across the middle line. The anterior muscular portion
+is the <i>frontalis</i>. Its lower border is attached to the skin
+of the eyebrow, and blends with the orbicularis palpebrarum. From
+this origin its fibres ascend vertically and parallel to each other
+towards the region of the roots of the hair, and<span class="pagenum" id="Page_317">[317]</span> become continuous,
+at this level, with the membranous expansion of the <i>epicranial
+aponeurosis</i>. This aponeurosis, which covers the vault of the skull
+and is adherent to the skin of the scalp, is prolonged backwards to the
+occipital region, where it terminates in a bilateral fleshy layer, the
+<i>occipitalis</i> muscle, attached to the superior curved line of the
+occipital bone.</p>
+
+  <div class="figcenter" id="i_317" style="max-width: 250px">
+     <img
+    class="p2"   
+    src="images/i_317.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 96.</p>
+     <p class="p0 sm center">Diagram of the <i>frontal muscles</i> (<i>attention</i>).</p>
+  </div>
+
+<p>In order to understand the mechanism of the occipito-frontalis muscle
+it is necessary to consider it as taking its fixed origin at the
+posterior part of the skull, through the medium of the epicranial
+aponeurosis and the occipitalis portion of the muscle; its insertion is
+its attachment to the deep surface of the skin of the eyebrow and the
+orbicularis palpebrarum. It has no bony attachment in the region of the
+forehead. The frontalis, therefore, in contracting, draws the skin of
+the eyebrow and the upper eyelid from below upwards, and consequently
+raises the eyebrow, and causes transverse folds to appear in the skin
+of the forehead.</p>
+
+<p>In examining (Fig. <a href="#i_316">95</a>) a face in which this muscle is contracted we
+perceive that it expresses <i>attention</i>; if the contraction of
+the muscle is very great this expression of attention changes to that
+of <i>astonishment</i>. In entering into the detail of the changes
+that the face then presents we see that the eyebrow is raised and its
+superior convexity is very marked, that the eye is widely opened,
+clear, and brilliant, and<span class="pagenum" id="Page_318">[318]</span> that the forehead is furrowed on each
+lateral half by curved folds concentric with the curve of the eyebrows,
+continued more or less from one side to the other, and describing
+curves in the middle line with the concavity upwards. In a child or
+young woman, in whom the skin is supple and elastic, it does not give
+rise to the formation of folds, and the skin of the forehead remains
+quite smooth during the contraction of the frontal muscle, and then the
+elevation of the eyebrow, the exaggeration of its curve and the state
+of the eyes, open and bright, are sufficient to give the expression of
+attention.</p>
+
+  <div class="figcenter" id="i_318" style="max-width: 250px">
+     <img
+    class="p2"   
+    src="images/i_318.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 97.</p>
+     <p class="p0 sm center"><span class="smcap">The Upper Part of the Orbicularis Palpebrarum</span>
+(<i>reflection</i>).</p>
+  </div>
+
+<p>Figure <a href="#i_317">96</a> is the representation of <i>attention</i>, characterised here
+solely by the form of the eyebrows and the frontal folds.</p>
+
+<p>2nd. <i>The orbicularis palpebrarum</i> (6, Fig. <a href="#i_285">88</a>, and 10, Fig.
+<a href="#i_315">94</a>).—The orbicular muscle of the eyes is a very extensive muscle which
+encircles the palpebral orifice. It is composed of numerous portions
+which can act more or less independently, and which have not all an
+equal importance in the expression of the face.</p>
+
+<p><i>a.</i> One part of this orbicular muscle, called the <i>palpebral
+part</i>, is contained in the thickness of the<span class="pagenum" id="Page_319">[319]</span> eyelids, and produces
+by its contraction the closing of the eyes. If this contraction is
+moderate it produces only a certain drawing together of the eyelids
+and reduces the opening of the eyes to the form of a linear slit.
+This state of the palpebral opening does not constitute by itself
+an expression, properly speaking, but it may be complementary to
+various expressions; thus, associated with a slight contraction of
+the triangular muscle of the lips, which is the muscle of disgust and
+discontent (page 333), it gives to the countenance the expression of
+disdain and contempt.</p>
+
+  <div class="figcenter" id="i_319" style="max-width: 250px">
+     <img
+    class="p2"   
+    src="images/i_319.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 98.</p>
+     <p class="p0 sm center">Diagram representation of <i>reflection, meditation</i>.</p>
+  </div>
+
+<p><i>b.</i> A second part of the orbicular muscle is arranged in a
+circular manner on the outer side of the eyelids, and corresponds
+exactly to the contour of the orbital orifice of the skeleton (Fig. <a href="#i_174">58</a>,
+page 174, and Fig. <a href="#i_285">88</a>, page 285). This portion, which we may call the
+<i>orbital portion</i>, is divided into two parts: one, the <i>inferior
+fibres</i>, the contraction of which moves the lower eyelid slightly
+upwards and causes a furrow at its junction with the cheek, and without
+being expressive by itself, completes the expression of laughter by
+giving to it a character of frankness and truth; and the <i>superior
+fibres</i>, which merit more detailed study, for they produce by their
+action a characteristic expression of reflection, meditation, and
+contemplation.</p>
+
+<p><span class="pagenum" id="Page_320">[320]</span></p>
+
+<p>This <i>superior orbital</i> portion of the muscle (muscle of
+<i>reflection</i>) is placed beneath the skin of the eyebrow, and its
+fibres, like it, describe an arc with the concavity downwards, of which
+the inner extremity is adherent to the internal border of the orbital
+opening. The mechanism, therefore, of this muscle is easily foreseen;
+for, like all curved muscles, more or less fixed at their extremities,
+it must in contraction straighten its curve. It accordingly acts
+in this way on the eyebrow, to the skin of which it is adherent,
+and effaces its curve, rendering it straight transversely; and it
+depresses, and consequently makes tense, the skin of the forehead,
+causing its wrinkles to disappear.</p>
+
+  <div class="figcenter" id="i_320" style="max-width: 250px">
+     <img
+    class="p2"   
+    src="images/i_320.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 99.</p>
+     <p class="p0 sm center"><span class="smcap">Superciliary Muscle</span> (<i>sorrow</i>).</p>
+  </div>
+
+<p>In examining a face in which this muscle is contracted we perceive
+that it expresses reflection. In Figure <a href="#i_318">97</a>, owing to the excessive
+development of the eyebrow, which is greatly lowered, the hairs descend
+over the eyes, and the expression is rather that of painful reflection
+or of intense application of the mind pre-occupied with sadness; but
+we see in every case that this expression is obtained essentially by
+the lowering and straight direction of the eyebrow,<span class="pagenum" id="Page_321">[321]</span> which veils the
+eye and effaces all wrinkles on the forehead. This alteration in the
+features is precisely the reverse of that produced by the frontalis
+muscle, as is shown by the comparison of Figures <a href="#i_316">95</a> and <a href="#i_317">96</a>, and in
+fact the two states of mind corresponding to the expression given by
+each of the muscles are precisely the reverse of each other. We cannot
+be at the same time attentive to an external object and meditating in
+reflection. Usually the succession of these states of mind and facial
+expression is as follows:—We are attentive to that on which we are
+looking, the eye open, brilliant, the eyebrow raised, and the forehead
+wrinkled (contraction of the frontal muscle); afterwards we reflect on
+what we have seen, and are, so to speak, abstracted from the external
+world—the eyebrow is lowered, the forehead smooth, and the eye veiled
+(by contraction of the superior fibres of the orbicularis palpebrarum),
+or the eyes may be closed (by contraction of the whole of the muscle).</p>
+
+  <div class="figcenter" id="i_321" style="max-width: 250px">
+     <img
+    class="p2"   
+    src="images/i_321.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 100.</p>
+     <p class="p0 sm center">Diagram representation of <i>sorrow</i>.</p>
+  </div>
+
+<p>Figure <a href="#i_319">98</a> is the representation of <i>reflection</i>, characterised
+by the absence of the frontal folds, the depression of the eyebrows
+and the presence of two small vertical folds in the space between the
+eyebrows, to which the depression of the eyelid gives rise (Fig. <a href="#i_318">97</a>).
+This representation of reflection (Fig. <a href="#i_319">98</a>) does not acquire its full
+demonstrative significance until we compare it with that of attention
+(Fig. 96).</p>
+
+<p><span class="pagenum" id="Page_322">[322]</span></p>
+
+<p>3rd. <i>Pyramidalis nasi muscle</i> (or <i>muscle of menace</i>).—This
+small muscle, situated in the space between the eyebrows on a level
+with the root of the nose (11, Fig. <a href="#i_315">94</a>) (9, Fig. <a href="#i_285">88</a>, page 285), is
+formed by short vertical fibres, which is attached by its lower end to
+a membranous expansion over the nasal bones (Fig. <a href="#i_174">58</a>, page 174), and by
+its upper end to the deep surface of the skin of the space between the
+eyebrows.</p>
+
+  <div class="figcenter" id="i_322" style="max-width: 250px">
+     <img
+    class="p2"   
+    src="images/i_322.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 101.</p>
+     <p class="p0 sm center"><span class="smcap">Great Zygomatic Muscle</span> (expression of <i>gaiety</i>, of
+<i>laughter</i>).</p>
+  </div>
+
+<p>The contraction of this muscle therefore produces the following
+result:—Taking its fixed insertion at the nasal bones, it draws
+downward the skin of the space between the eyebrows, forming short
+transverse folds, and depressing slightly the inner part of the eyebrow.</p>
+
+<p>In a face in which this muscle is contracted (see the atlas of
+Duchenne) the expression is that of harshness, menace, and aggression.
+Looking at the expression of countenance which Duchenne reproduced by
+this contraction, we can readily believe that if the subject had been
+represented in full, its attitude would have been one of menace; and
+the individual would be shaking his fist or brandishing<span class="pagenum" id="Page_323">[323]</span> a weapon.
+Moreover, anything which throws a shadow or a dark look between the
+eyebrows gives to the physiognomy a character of harshness, as when the
+contraction of the pyramidalis produces the transverse folds in this
+region. Therefore, in those persons in whom the eyebrows seem to meet,
+owing to an exaggerated development of hair in the space between, the
+physiognomy always presents at first sight the stamp of severity and
+harshness, which may not agree in the least with the true character of
+the subject. The expression of the pyramidalis is too delicate, and due
+to a change of the features too local and slight for us to express it
+by a drawing, as we have done in the case of the preceding muscles.</p>
+
+<p>4th. <i>Superciliary muscle</i> (<i>corrugator supercilii</i>, or
+muscle of pain).—This short muscle is deeply hidden beneath the skin
+of the region of the head of the eyebrow. Its fixed attachment is to
+the frontal bone, above the superciliary arch; from this origin its
+fibres are directed outwards and slightly downwards to be inserted into
+the deep surface of the skin at the middle of the eyebrow.</p>
+
+<p>Its mechanism consists in drawing the eyebrow inwards and slightly
+upwards, and as it is attached to the middle of the eyebrow it draws
+it together at this point, namely, towards its inner part. The eyebrow
+is therefore, so to speak, abruptly hooked upwards and inwards, like
+a curtain that has been tucked up and attached to a fixed point. It
+therefore produces on the skin of the forehead folds concentric to
+this gathering together of the eyebrow and situated in the middle of
+the forehead, besides<span class="pagenum" id="Page_324">[324]</span> producing the vertical furrows, obvious in the
+figures, between the eyebrows.</p>
+
+<p>Figure <a href="#i_320">99</a> represents, after a photograph of Duchenne, the state of
+the physiognomy caused by the contraction of the superciliary muscle.
+This physiognomy has an expression characteristic of suffering, and
+any greater accentuation of the action of the muscle shows in a marked
+degree the expression of physical or mental agony.</p>
+
+<p>We see that the only parts changed in this expression (compare Fig.
+<a href="#i_316">95</a>, page 315) are the inner half of the eyebrow and the region between
+the eyebrows on the forehead; pain, therefore, is expressed by the
+raising of this part of the eyebrow and its gathering together abruptly
+in the middle of the forehead, and by the presence of the short folds
+immediately above this and the more extended folds occupying the middle
+region of the forehead.</p>
+
+<p>Figure <a href="#i_321">100</a> is a diagrammatic representation of pain, expressed only by
+changes in the neighbourhood of the inner part of the eyebrow (contrast
+with Fig. <a href="#i_325">102</a> following).</p>
+
+
+<p class="center p1 smcap lg">B.—Muscles of the middle region of the face.</p>
+
+<p>5th. The <i>great zygomatic muscle</i> (<i>zygomaticus major</i>,
+muscle of <i>laughter</i>).—This muscle (17, Fig. <a href="#i_315">94</a>, and 11, Fig.
+<a href="#i_285">88</a>) has its fixed attachment on the cheek-bone; from this origin it is
+directed obliquely downwards and forwards, to be inserted into the deep
+surface of the skin near the angle of the mouth.</p>
+
+<p><span class="pagenum" id="Page_325">[325]</span></p>
+
+<p>6th. <i>Elevator of the angle of the month.</i>—<i>The levator anguli
+oris</i> is a muscle which largely aids the great zygomatic muscle in
+its action. It arises from the canine fossa of the upper jaw, and is
+directed downwards towards the angle of the mouth. It is inserted into
+the skin, and blends with the orbicularis oris (15, Fig. <a href="#i_315">94</a>).</p>
+
+  <div class="figcenter" id="i_325" style="max-width: 250px">
+     <img
+    class="p2"   
+    src="images/i_325.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 102.</p>
+     <p class="p0 sm center">Diagram representation of <i>laughter</i>.</p>
+  </div>
+
+<p>The mechanism of these muscles consists in drawing the angle of the
+mouth upwards and outwards, an action which results in some complex
+changes in the expression of the countenance. At first the orifice
+of the mouth is enlarged transversely, and its direction ceases to
+be straight, so that each lateral half is directed obliquely upwards
+and outwards. As the naso-labial line (Fig. <a href="#i_316">95</a>) passes, at its lower
+end, near the commissure of the lips, this also is carried upwards,
+describing a slight curve concentric to the commissure of the lips,
+while the upper part of the line describes a curve with its convexity
+downwards. The skin of the cheek gathered up towards the cheek-bone
+becomes more prominent, and forms, below the outer angle of the eye,
+several radiating folds (commonly called crows’-feet), which throw a
+slight shadow beneath the external angle of the eye; this makes it
+appear as if the line of the eyelids is a little raised on the outer
+side (or oblique upwards).</p>
+
+<p>Figure <a href="#i_322">101</a>, representing the contraction of the great<span class="pagenum" id="Page_326">[326]</span> zygomatic
+muscle, illustrates in a diagram the frank expression of gaiety and
+laughter, and we see that the alterations of expression take place
+only, as we have already said, in the line of the lips, the naso-labial
+line, and the external angle of the eyes.</p>
+
+  <div class="figcenter" id="i_326" style="max-width: 250px">
+     <img
+    class="p2"   
+    src="images/i_326.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 103.</p>
+     <p class="p0 sm center">Diagram representation of the <i>external common elevator</i> (muscle
+of <i>grief</i>).</p>
+  </div>
+
+<p>Figure <a href="#i_325">102</a>, giving the representation of laughter according to the
+preceding description of the great zygomatic muscle, is very similar
+to the corresponding figure of Humbert de Superville (Fig. <a href="#i_299">92</a>, page
+299), only, in order to express the reality without having regard here
+to appearances, we have drawn the lines of the eyes horizontal; and,
+again, the naso-labial furrow has been represented with its form convex
+downwards and inwards for the upper two-thirds, and with the slight
+hook which its inferior extremity describes. This naso-labial furrow is
+of the utmost importance in the expressions produced by all the muscles
+belonging to the lips, as we shall see in the following description.</p>
+
+<p>7th. The <i>lesser zygomatic</i> (<i>zygomaticus minor</i>) <i>and
+elevator of the upper lip</i> (<i>levator labii superioris</i>, muscle
+of <i>grief</i>).—On the inner side of the great zygomatic muscle
+there exists frequently (10, Fig. <a href="#i_285">88</a>, page 285), but not constantly,
+a small muscular fasciculus which arises from the anterior part of
+the cheek-bone and descends to be inserted into the thickness of the
+upper lip. This muscle, called the <i>lesser zygomatic</i>, does not
+take part in the expression<span class="pagenum" id="Page_327">[327]</span> of laughter; in fact, it changes the
+naso-labial furrow in the same manner as the following muscle (the
+external common elevator), and so expresses, as we shall see, emotion,
+sadness, and grief.</p>
+
+<p>8th. The <i>elevator</i> of the upper lip (<i>levator labii
+superioris</i>) arises (14, Fig. <a href="#i_315">94</a>, and 14, Fig. <a href="#i_285">88</a>, page 285) from
+the inferior border of the bony margin of the orbit and descends to the
+upper lip.</p>
+
+  <div class="figcenter" id="i_327" style="max-width: 250px">
+     <img
+    class="p2"   
+    src="images/i_327.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 104.</p>
+     <p class="p0 sm center">Diagram representation of the <i>internal common elevator</i> (muscle
+of <i>grief</i> with tears).</p>
+  </div>
+
+<p>Its contraction raises the upper lip itself, but not the labial
+commissure, so that each half of the line of the lips, raised within
+and remaining depressed at its outer extremity, becomes slightly
+oblique from above downwards and from within outwards (the reverse of
+the obliquity produced by the great zygomatic muscle); at the same time
+the centre of the naso-labial furrow is raised and the furrow becomes
+curved with its concavity downwards and inwards (the reverse of the
+curve produced by the great zygomatic).</p>
+
+<p>By means of these changes the countenance takes on the expression of
+discontent, emotion, and grief (see the atlas of Duchenne).</p>
+
+<p>We give here only one drawing (Fig. <a href="#i_326">103</a>) in which are shown the two
+essential changes produced by this muscle (obliquity of the line of the
+lips and curve of the naso-labial furrow), which seems to us to show in
+a satisfactory manner the expression of grief in tears. We comprehend
+the<span class="pagenum" id="Page_328">[328]</span> value of this drawing better by comparing it with Figure <a href="#i_325">102</a>.
+We see that the changes produced by the muscle of grief (lip and
+naso-labial furrow) are precisely the reverse of those produced by
+the muscle of laughter (<i>zygomaticus major</i>), just as the two
+corresponding emotions are the reverse of each other. We remark also
+how slight is the distance which separates these two muscles, and how
+delicate are the shades of anatomical arrangement which separate them,
+so delicate that authors do not agree as to whether the muscle found
+between them, the lesser zygomatic muscle, when it exists, should be
+considered as associated with the great zygomatic or, as we think,
+with the common elevator of the nose and upper lip. Beyond doubt their
+anatomical relations should remind us, in the nature of the emotions
+and their expression, how small a distance there is between laughter
+and tears.</p>
+
+<p>9th. The elevator of the nose and upper lip (<i>levator labii
+superioris alæque nasi</i>, muscle of sobbing, of weeping
+bitterly).—This muscle (13, Fig. <a href="#i_315">94</a>, and 7, Fig. <a href="#i_285">88</a>) arises above from
+the inner border of the orbit; it descends almost vertically to be
+inserted by some of its fibres into the wing of the nose, and by the
+majority into the upper lip, not far from its central portion.</p>
+
+<p>It therefore raises the middle part of the lip, the labial commissure
+remaining fixed, and gives accordingly to each half of the line of the
+lips a direction oblique downwards and outwards (like the preceding
+muscle, but in a more characteristic manner); at the same time it
+dilates the nostril<span class="pagenum" id="Page_329">[329]</span> by raising the wing of the nose; lastly, by the
+traction that it exercises vertically on the skin of the naso-labial
+furrow, it raises <i>en masse</i> the inner and upper part of this
+furrow and renders it straight, causing it to form a species of groove
+wherein the tears flow when they pour abundantly from the inner angle
+of the eyelids. These changes (see the atlas of Duchenne) give to the
+countenance the expression of grief with abundant tears, or of weeping
+bitterly.</p>
+
+<p>The drawing of Figure <a href="#i_327">104</a> renders this expression to a certain degree,
+but it is difficult to realise it with the simple elements we use in
+these formulæ. We see that all the folds of the face converge towards
+the inner angle of the eye, or towards the point of attachment of this
+muscle.</p>
+
+<p>10th. <i>Transverse muscle of the nose</i> (<i>compressor naris</i>,
+muscle of <i>lasciviousness</i>).—This muscle (12, Fig. <a href="#i_315">94</a>, and 9,
+Fig. <a href="#i_285">88</a>) is attached at its origin to the skin of the cheek on a level
+with the side of the nose, and is directed transversely forwards over
+the nose to join a thin aponeurosis which stretches over the bridge of
+the nose, and receives the insertions of these two muscles, and that of
+the pyramidalis nasi.</p>
+
+<p>This aponeurosis, which covers the bridge of the nose, forms a fixed
+point towards which these muscles draw the skin of the cheek and nose,
+so as to mark on the lateral surface of the nose a series of vertical
+folds (perpendicular to the direction of the muscle).</p>
+
+<p>Duchenne considered the change produced by these muscles to be
+characteristic of the expression of lasciviousness. Perhaps this muscle
+by itself is not<span class="pagenum" id="Page_330">[330]</span> sufficiently expressive, but when its contraction
+accompanies that of certain other muscles, we find very clearly in the
+physiognomy the element of lewdness pointed out by Duchenne. In his
+atlas this author gives the photograph of a countenance in which he
+had produced contraction of the frontalis, the great zygomatic, and
+the compressor naris; a countenance of which the expression may be
+directly interpreted as that of an old man in whom the <i>attention</i>
+(frontalis muscle) is <i>agreeably</i> excited (great zygomatic) by
+a spectacle arousing <i>lewd</i> ideas (compressor naris); the face
+produced by Duchenne would be, for example, a study in physiognomy for
+the head of the old man in the classic subject of Susanna in the bath.</p>
+
+<p>We have not attempted to represent by a drawing an unsatisfactory and
+perhaps doubtful idea of the expression of this muscle.</p>
+
+
+<p class="center p1 lg smcap">C.—Muscles of the lower part of the face.</p>
+
+<p>11th. <i>Orbicularis muscle of the lips</i> (<i>orbicularis
+oris</i>).—In the substance of the lips, as in the eyelids, a
+muscle is found, the fibres of which surround the orifice of the
+mouth—the orbicularis oris (19, Fig. <a href="#i_315">94</a>, and 15, Fig. <a href="#i_285">88</a>). This
+muscle principally possesses functions not primarily pertaining to
+expression, but to the various uses of the lips—prehension of food,
+mastication, speech, suction, etc.; the part it takes in physiognomy,
+although of importance, is secondary to these elemental functions.
+As in the orbicular muscle of the eyelids, we distinguish in it
+internal fibres corresponding to the free border of the lips and
+external<span class="pagenum" id="Page_331">[331]</span> fibres more peripherally placed. If the inner fibres only
+contract (internal orbicular) they close the mouth, and, diminishing
+the size of the orifice, cause the red surfaces of the lips to be
+brought closely together in their whole extent. If the outer fibres
+(external orbicular) contract only, they project the lips forwards and
+render their surfaces prominent and rounded, as in the expression of
+<i>pouting</i> or in <i>kissing</i>.</p>
+
+<p>We need not dwell at length on the muscle which constitutes the fleshy
+layer of the cheeks and forms the lateral walls of the cavity of the
+mouth. This muscle, called the <i>buccinator</i> (<i>buccinare</i>,
+to play the trumpet), is a thin sheet of muscle (21, Fig. <a href="#i_315">94</a>) lining
+the hollow of the cheek in front of the line of the masseter. It is
+separated from that muscle posteriorly by a pad of fat (the remains of
+a suctorial pad), which in the infant is an important aid in suckling,
+and may be seen projecting into the side of the mouth. It takes a part
+in movements associated with the actions of the tongue and lips; it
+plays an important part in mastication by bringing beneath the crown of
+the teeth the food which passes outside the alveolar arches. It also
+aids in the articulation of sounds (speech) and in whistling and the
+playing of wind instruments (whence its name of <i>buccinator</i>), for
+it is the contraction of this muscle that expels from the mouth the
+air which inflates the cheeks. By its insertion into the angle of the
+mouth, where its fibres decussate with those of the orbicularis muscle,
+the buccinator is able to some extent to assist in the retraction of
+the mouth, as in grinning or snarling.</p>
+
+<p>12th. <i>The depressor of the angle of the mouth</i><span class="pagenum" id="Page_332">[332]</span> (<i>depressor
+anguli oris</i>, muscle of <i>contempt</i>).—This muscle belongs to
+the lower lip. It forms (22, Fig. <a href="#i_315">94</a>, and 16, Fig. <a href="#i_285">88</a>) a triangular
+layer, of which the base is attached to the lower jaw, external to the
+symphysis of the chin, and from this origin its fibres converge towards
+the angle of the mouth, where, by its apex, it is inserted into the
+deep surface of the skin.</p>
+
+  <div class="figcenter" id="i_332" style="max-width: 250px">
+     <img
+    class="p2"   
+    src="images/i_332.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 105.</p>
+     <p class="p0 sm center"><span class="smcap">Triangular Muscle of the Lips</span> (expression of
+<i>discontent</i>, of <i>contempt</i>).</p>
+  </div>
+
+<p>This muscle depresses the labial commissure, and therefore renders the
+line of the lips oblique in a direction downwards and outwards; again,
+it draws downwards the lower extremity of the naso-labial furrow so as
+to render this furrow almost straight, except at its lower end, which
+describes a slight curve embracing the labial commissure.</p>
+
+<p>The expression produced by a slight contraction of this muscle is
+that of <i>sadness</i>; marked contraction produces the expression of
+<i>contempt</i>. We have already seen (page 319) that a partial closing
+of the eyelids usually helps to complete the expression of contempt.
+Two other movements assist in this expression—a contraction of the
+common elevator of the nose and upper lip, raising the ala of the nose<span class="pagenum" id="Page_333">[333]</span>
+and curling the lip upwards; and a movement of the head to the opposite
+side. All these movements may have, as Darwin pointed out, a rational
+physical basis—the expression of the mouth implying a disagreeable
+taste, the uplifting of the nose an unpleasant smell, and the aversion
+of the head a disgusting sight.</p>
+
+  <div class="figcenter" id="i_333" style="max-width: 250px">
+     <img
+    class="p2"   
+    src="images/i_333.jpg"
+     alt="">
+     <p class="p0 sm center smcap">Fig. 106.</p>
+     <p class="p0 sm center">Diagram representation of the expression of <i>discontent</i>, of
+<i>contempt</i>.</p>
+  </div>
+
+<p>Figure <a href="#i_332">105</a>, copied from Duchenne, renders well, by the contraction
+only of the two triangular muscles of the lips, the expression of
+discontent and scorn. The depression of the angles of the mouth is
+characteristic, and the naso-labial furrow, very marked in the subject
+under experiment, is greatly changed in its direction and in the form
+of its inferior extremity, according to the mechanism that we have
+explained.</p>
+
+<p>Lastly, the drawing of Figure <a href="#i_333">106</a> gives, so to speak, a diagrammatic
+formula of contempt by means of the form of the inferior part of the
+naso-labial furrow, and the concentric folds which it produces below
+the angle of the mouth.</p>
+
+<p>13th. The <i>depressor of the lower lip</i> (<i>quadratus menti:
+depressor labii inferioris</i>, muscle of <i>disgust</i>).—This muscle
+(23, Fig. <a href="#i_315">94</a>, and 17, Fig. <a href="#i_285">88</a>), partly hidden by the depressor anguli
+oris, arises from the anterior part of the body of the lower jaw; from
+this origin the fibres ascend obliquely upwards and inwards to be
+inserted into the whole length of the lower lip.</p>
+
+<p><span class="pagenum" id="Page_334">[334]</span></p>
+
+<p>This muscle’s action is to depress the lower lip, turning it outwards
+more or less strongly, so as to produce the grimace characteristic of
+a person who, having introduced into the cavity of the mouth a morsel
+of food which he does not find to his taste, rejects it forcibly,
+forming a species of groove with the lower lip turned outwards; if the
+contraction is less energetic the physiognomy expresses disgust.</p>
+
+<p>We must refer to the atlas of Duchenne for the reproduction of this
+expression, always more or less rude, and have not attempted a drawing
+with a simple line as an indication of the labial fissure.</p>
+
+<p>14th. <i>Platysma muscle of the neck</i> (<i>platysma myoides</i>).—In
+each lateral half of the anterior surface of the neck is a thin
+muscular sheet situated beneath the skin (25, Fig. <a href="#i_315">94</a>, and 25, Fig.
+<a href="#i_217">74</a>, page 217). This platysma muscle is attached below to the upper
+part of the chest, from which origin its fibres are directed obliquely
+upwards and forwards towards the lower jaw, to be inserted into the
+edge of the jaw, and the skin of the chin, of the lower lip, and the
+commissure of the lips; the more superior fibres sweep forwards in a
+horizontal direction across the cheek towards the labial commissure,
+and constitute the <i>risorius muscle</i> of Santorini (20, Fig. <a href="#i_315">94</a>).</p>
+
+<p>The platysma, which is not of itself essentially a muscle of
+expression, adds its contraction to that of various muscles of the
+face, so as to give to the corresponding expression a character
+of terrible energy; the <i>risorius</i> muscle does not therefore
+produce the expression of laughter (of gaiety), but only that of
+<i>grinning</i>, of forced laughter, threatening or sneering. The
+platysma in all these cases acts by depressing the<span class="pagenum" id="Page_335">[335]</span> lower jaw, slightly
+opening the mouth, and drawing the labial commissure downwards; it
+marks at the same time a series of transverse folds on the skin of
+the neck. These elements are capable of giving to the physiognomy a
+terrible character, which Leonardo da Vinci has well observed, in his
+chapter on the mode of representing a person in a state of violent
+anger, where he says, “it makes the sides of the mouth into a bow, the
+neck thick and swollen, and marked with wrinkles in front.”</p>
+
+<p>If the characteristic changes produced by the contraction of the
+platysma of the neck occur along with the contraction of the frontalis
+muscle, the countenance, as shown in Duchenne’s series of photographs,
+takes on an expression of attention and astonishment such as might be
+produced by a terrible spectacle. Associated with the contraction of
+the <i>superciliary</i> muscle, the expression becomes that of acute
+pain, as, for example, in a wretch under torture, or a victim torn by
+a beast of prey. If the contraction of the <i>pyramidalis nasi</i> is
+accompanied by that of the platysma we have the expression of a savage
+and barbarous threat.</p>
+
+<p><i>General considerations.</i>—<i>Associations and
+combinations.</i>—From the enumeration we have made of the facial
+muscles from the forehead to the neck, we must perceive that among
+these muscles there are some which are by themselves completely
+expressive (<i>e.g.</i>, the frontal, superciliary, and great
+zygomatic), and others which are expressive only in a complementary
+sense, or intended only to complete or change an expression produced by
+another muscle (such are the palpebral portion<span class="pagenum" id="Page_336">[336]</span> of the orbicularis of
+the eyelids, and the platysma of the neck), and lastly, others which
+are almost non-expressive, but yet associated with the true muscles of
+the expression (<i>e.g.</i> the buccinator). But we have not space here
+to dwell on these classifications.</p>
+
+<p>A more important question is that of the association of the action of
+various muscles, and especially of the muscles which are completely
+expressive by themselves. The expression peculiar to each of these
+muscles is, so to speak, one of the syllables or words of the language
+of physiognomy, but, like every other language, physiognomy associates
+these syllables and words to arrive at its expressions. Now experience
+shows that usually the associations and combinations are composed of
+few elements. Usually two suffice; three muscles are sometimes in play
+simultaneously, hardly ever four.</p>
+
+<p>Again, if we endeavour to realise these combinations theoretically by
+supposing the contractions of two muscles associated at random, we
+soon perceive that among the combinations some are easy and ordinary,
+and this is on account of the nature of emotions which we suppose
+associated, and the mechanism of the corresponding muscles, while
+others are impossible for the same reason.</p>
+
+<p>The following is an example of easy combination related at the same
+time to the emotions and also to the muscular mechanism—viz., the
+combination of the contraction of the frontalis and of the great
+zygomatic muscles, as expressive of attention and laughter. On the one
+hand, attention<span class="pagenum" id="Page_337">[337]</span> (frontalis) might be excited by a spectacle which
+provokes laughter (zygomatic); on the other hand, the frontal muscle
+and the great zygomatic being situated the one in the forehead and
+the other in the cheek, acting, one on the eyebrow, the other on the
+lips, the mechanism of one is independent of that of the other; this,
+however, from an anatomical point of view, does not prevent the two
+contracting simultaneously, exactly as the biceps might contract in
+order to flex the forearm, at the same time that the common extensor of
+the fingers extends the digital phalanges.</p>
+
+<p>On the other hand, as impossible combinations discordant both to
+sentiment and muscular mechanism, we may, for example, consider the
+simultaneous contraction of the frontalis and the superior orbital
+portion of the orbicularis muscles of the eyelids. The first muscle
+expresses attention, the second reflection, or two opposite states of
+the mind, which cannot at the same time be open to external phenomena,
+and meditating on internal analyses. Again, the first muscle raises,
+the second depresses the eyebrow, which cannot be at the same time
+drawn in two opposite directions; just as, to take an example from the
+muscles of the limbs, the forearm cannot be at the same time flexed by
+the action of the biceps and extended by that of the triceps.</p>
+
+<p>By submitting them to the same analysis we see that nothing is easier
+or more concordant to their mechanism and to the emotions than the
+simultaneous contraction of the frontalis and the depressor anguli
+oris (attention and contempt), of the superciliary<span class="pagenum" id="Page_338">[338]</span> and the depressor
+labii inferioris (pain and disgust), the pyramidalis and the common
+elevator of the nose and upper lip (menace and sorrow), etc. On the
+contrary, for the same double series of reasons we find impossible and
+discordant associations, such as those of the great zygomatic and the
+depressor labii inferioris (gaiety and disgust), the pyramidalis and
+the superciliary (menace and pain), and of the common elevator of the
+nose and upper lip and the great zygomatic (sorrow and laughter).</p>
+
+<p>There are, however, combinations which at first sight appear discordant
+to the nature of the passions, but which are found, notwithstanding,
+not to have any obstacle to their realisation in the mechanism of the
+countenance. We take, for example, the superciliary and the great
+zygomatic: one expresses pain, the other laughter—two expressions of
+an opposite nature; however, as these muscles correspond, one belonging
+to the head of the eyebrow, the other to the labial commissure,
+they can act without one counteracting the other, and we may well
+understand their simultaneous contraction. Now on reflection we find
+that this association, anatomically possible, is often realised,
+notwithstanding the apparent incompatibility of the corresponding
+passions. In the midst of violent physical pain, which causes the
+involuntary and irresistible contraction of the superciliary, a
+serene and powerful will finds still the energy to smile. In order to
+find the realisation in a work of art it is sufficient to study the
+expression of the countenance of Seneca in the painting by Giordano. A
+similar example is offered by that of a young woman who has become a
+mother, and who, though still quivering<span class="pagenum" id="Page_339">[339]</span> with the pain of childbirth
+(<i>superciliary</i> muscle), is divided betwixt the physical pain and
+the mental joy of seeing the infant to whom she has given birth and at
+whom she smiles (<i>great zygomatic</i> muscle).</p>
+
+<p>These latter examples show that the anatomical conditions take the lead
+up to a certain point of those conditions which result from the nature
+of the emotions, and that a combination of expressions is possible only
+when it can be realised by the action of the facial muscles.</p>
+
+<p>We will finish here these short studies of the anatomy of the face,
+happy if we have been successful in showing the artist that in the
+movements of the face there is neither fancy, caprice, nor inspiration,
+but that all is subject to exact and precise rules which are the
+orthography of the language of physiognomy, and that the possible
+combinations are both large and varied, so that the artist can preserve
+his liberty of action while conforming to these rules, as the poet
+observes those of grammar without being on that account embarrassed in
+the scope of his genius.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_341">[341]</span></p>
+
+<h2>INDEX</h2>
+</div>
+
+  <div class="figcenter">
+  <img
+    class="p1" 
+    src="images/i_341.jpg"
+    alt="">
+  </div>
+
+<p class="p-index">A</p>
+
+<ul>
+  <li class="i1">Abdomen, Form of,
+    <a href="#Page_199">199</a></li>
+
+  <li class="i1">Abdomen, Muscles of,
+    <a href="#Page_198">198</a></li>
+
+  <li class="i1">Abduction and Adduction,
+    <a href="#Page_118">118</a>,
+    <a href="#Page_121">121</a></li>
+
+  <li class="i1">Abductor Pollicis,
+    <a href="#Page_248">248</a></li>
+
+  <li class="i1">Acetabulum,
+    <a href="#Page_106">106</a></li>
+
+  <li class="i1">Achilles, Tendon of,
+    <a href="#Page_277">277</a></li>
+
+  <li class="i1">Acromio-clavicular Articulation,
+    <a href="#Page_57">57</a></li>
+
+  <li class="i1">Acromion Process,
+    <a href="#Page_57">57</a></li>
+
+  <li class="i1">Adductor Muscles of Hand,
+    <a href="#Page_248">248</a></li>
+
+  <li class="i1">Adductor Muscles of Thigh,
+    <a href="#Page_262">262</a></li>
+
+  <li class="i1">Agony, Expression of,
+    <a href="#Page_324">324</a></li>
+
+  <li class="i1">Alar Ligaments,
+    <a href="#Page_144">144</a></li>
+
+  <li class="i1">Alveoli, Dental,
+    <a href="#Page_178">178</a></li>
+
+  <li class="i1">Anatomical Neck of humerus,
+    <a href="#Page_60">60</a></li>
+
+  <li class="i1">Anatomical Snuff-box,
+    <a href="#Page_246">246</a></li>
+
+  <li class="i1">Anatomy, Definition and History of,
+    <a href="#Page_7">7</a></li>
+
+  <li class="i1">Anconeus Muscle,
+    <a href="#Page_240">240</a>,
+    <a href="#Page_242">242</a></li>
+
+  <li class="i1">Anger, Expression of,
+    <a href="#Page_335">335</a></li>
+
+  <li class="i1">Angular Processes,
+    <a href="#Page_168">168</a></li>
+
+  <li class="i1">Ankle-joint,
+    <a href="#Page_148">148</a></li>
+
+  <li class="i1">Annular Ligament, Anterior of Wrist,
+    <a href="#Page_88">88</a></li>
+
+  <li class="i1">Anterior Triangle of Neck,
+    <a href="#Page_283">283</a></li>
+
+  <li class="i1">Antinöus, Measurement of,
+    <a href="#Page_187">187</a></li>
+
+  <li class="i1">Antithesis of Expression,
+    <a href="#Page_306">306</a></li>
+
+  <li class="i1">Apollo, Measurement of,
+    <a href="#Page_187">187</a></li>
+
+  <li class="i1">Arm,
+    <a href="#Page_67">67</a>,
+    <a href="#Page_77">77</a></li>
+
+  <li class="i1">Arm, Muscles of,
+    <a href="#Page_224">224</a></li>
+
+  <li class="i1">Arm-pit, Hollow of,
+    <a href="#Page_215">215</a></li>
+
+  <li class="i1">Arthrology,
+    <a href="#Page_19">19</a></li>
+
+  <li class="i1">Articular Processes,
+    <a href="#Page_30">30</a></li>
+
+  <li class="i1">Association of Expressions,
+    <a href="#Page_336">336</a></li>
+
+  <li class="i1">Astragalo-calcaneo-scaphoid Joint,
+    <a href="#Page_157">157</a></li>
+
+  <li class="i1">Astragalo-scaphoid Articulation,
+    <a href="#Page_157">157</a></li>
+
+  <li class="i1">Astragalus Bone,
+    <a href="#Page_148">148</a>,
+    <a href="#Page_152">152</a>,
+    <a href="#Page_155">155</a></li>
+
+  <li class="i1">Athletes, Ancient,
+    <a href="#Page_11">11</a></li>
+
+  <li class="i1">Atlas, Vertebra,
+    <a href="#Page_32">32</a></li>
+
+  <li class="i1">Atmospheric Pressure, Influence of,
+    <a href="#Page_123">123</a></li>
+
+  <li class="i1">Attention, Expression of,
+    <a href="#Page_316">316</a></li>
+
+  <li class="i1">Auditory Canal,
+    <a href="#Page_169">169</a></li>
+
+  <li class="i1">Auditory Meatus,
+    <a href="#Page_169">169</a></li>
+
+  <li class="i1">Axilla,
+    <a href="#Page_215">215</a></li>
+
+  <li class="i1">Axis, Vertebra,
+    <a href="#Page_32">32</a></li>
+</ul>
+
+<p class="p-index">B</p> 
+
+<ul>
+  <li class="i1">Back, Muscles of,
+    <a href="#Page_205">205</a></li>
+
+  <li class="i1">Bell, Sir Charles,
+    <a href="#Page_296">296</a></li>
+
+  <li class="i1">Bertini, Ligament of,
+    <a href="#Page_119">119</a></li>
+
+  <li class="i1">Biceps Brachialis,
+    <a href="#Page_224">224</a></li>
+
+  <li class="i1">Biceps Femoris,
+    <a href="#Page_266">266</a></li>
+	
+  <li class="i1">Biceps Muscle,
+    <a href="#Page_222">222</a>,
+    <a href="#Page_224">224</a></li>
+
+  <li class="i1">Bicipital Groove,
+    <a href="#Page_61">61</a>,
+    <a href="#Page_67">67</a></li>
+
+  <li class="i1">Bicipital Tubercle,
+    <a href="#Page_78">78</a></li>
+
+  <li class="i1">Bigelow, Ligament of,
+    <a href="#Page_119">119</a></li>
+
+  <li class="i1">Blanc, Charles,
+    <a href="#Page_99">99</a></li>
+
+  <li class="i1">Bone, Structure of,
+    <a href="#Page_25">25</a></li>
+
+  <li class="i1">Brachial Index,
+    <a href="#Page_100">100</a></li>
+
+  <li class="i1">Brachialis Anticus Muscle,
+    <a href="#Page_228">228</a></li>
+
+  <li class="i1">Brachio-radialis Muscle,
+    <a href="#Page_238">238</a></li>
+
+  <li class="i1">Brachycephalic of Skull,
+    <a href="#Page_172">172</a></li>
+
+  <li class="i1">Breast,
+    <a href="#Page_196">196</a></li>
+
+  <li class="i1">Buccinator Muscle,
+    <a href="#Page_331">331</a></li>
+
+  <li class="i1">Buttock,
+    <a href="#Page_121">121</a></li>
+</ul>
+
+<p class="p-index">C</p> 
+
+<ul>
+  <li class="i1">Calcaneum,
+    <a href="#Page_152">152</a></li>
+
+  <li class="i1">Camper on Facial Angle,
+    <a href="#Page_181">181</a>,
+    <a href="#Page_296">296</a></li>
+
+  <li class="i1">Canalis Tarsi,
+    <a href="#Page_155">155</a></li>
+
+  <li class="i1">Canine Fossa,
+    <a href="#Page_176">176</a></li>
+
+  <li class="i1">Canine Teeth,
+    <a href="#Page_175">175</a></li>
+
+  <li class="i1">Canons,
+    <a href="#Page_99">99</a>,
+    <a href="#Page_189">189</a></li>
+
+  <li class="i1">Capitellum,
+    <a href="#Page_68">68</a></li>
+
+  <li class="i1">Carpo-metacarpal Articulation,
+    <a href="#Page_92">92</a></li>
+
+  <li class="i1">Carpus,
+    <a href="#Page_87">87</a></li>
+
+  <li class="i1">Carpus, Muscles of,
+    <a href="#Page_239">239</a></li>
+
+  <li class="i1">Cartilages,
+    <a href="#Page_26">26</a></li>
+
+  <li class="i1">Caruncula Lachrymalis,
+    <a href="#Page_311">311</a></li>
+
+  <li class="i1">Caucasian Race, Facial Angle of,
+    <a href="#Page_184">184</a></li>
+
+  <li class="i1">Cephalic Index,
+    <a href="#Page_171">171</a></li>
+
+  <li class="i1">Cephalic Vein,
+    <a href="#Page_219">219</a></li>
+
+  <li class="i1">Cervical Vertebræ,
+    <a href="#Page_32">32</a></li>
+
+  <li class="i1">Cheek, Prominence of,
+    <a href="#Page_176">176</a></li>
+
+  <li class="i1">Chest,
+    <a href="#Page_41">41</a>,
+    <a href="#Page_51">51</a></li>
+
+  <li class="i1">Chin,
+    <a href="#Page_177">177</a></li>
+
+  <li class="i1">Chondro-costal Articulation,
+    <a href="#Page_52">52</a></li>
+
+  <li class="i1">Chondro-sternal Articulation,
+    <a href="#Page_52">52</a></li>
+
+  <li class="i1">Clavicle,
+    <a href="#Page_55">55</a>,
+    <a href="#Page_65">65</a></li>
+
+  <li class="i1">Coccyx,
+    <a href="#Page_104">104</a></li>
+
+  <li class="i1">Combination of Expressions,
+    <a href="#Page_336">336</a></li>
+
+  <li class="i1">Commissure of Eyelids,
+    <a href="#Page_319">319</a></li>
+
+  <li class="i1">Commissure of Lips,
+    <a href="#Page_311">311</a></li>
+
+  <li class="i1">Complexus Muscle,
+    <a href="#Page_211">211</a></li>
+
+  <li class="i1">Condyle of Jaw,
+    <a href="#Page_178">178</a></li>
+
+  <li class="i1">Condyles of Femur,
+    <a href="#Page_133">133</a></li>
+
+  <li class="i1">Condyles of Humerus,
+    <a href="#Page_69">69</a></li>
+
+  <li class="i1">Condyles, Occipital,
+    <a href="#Page_165">165</a></li>
+
+  <li class="i1">Conoid Ligament,
+    <a href="#Page_59">59</a></li>
+
+  <li class="i1">Contempt, Muscle of,
+    <a href="#Page_332">332</a></li>
+
+  <li class="i1">Coraco-brachialis Muscle,
+    <a href="#Page_215">215</a>,
+    <a href="#Page_222">222</a>,
+    <a href="#Page_227">227</a></li>
+
+  <li class="i1">Coracoid Process,
+    <a href="#Page_58">58</a></li>
+
+  <li class="i1">Coronal Suture,
+    <a href="#Page_167">167</a>,
+    <a href="#Page_170">170</a></li>
+
+  <li class="i1">Coronoid Fossa,
+    <a href="#Page_69">69</a></li>
+
+  <li class="i1">Coronoid Process,
+    <a href="#Page_70">70</a>,
+    <a href="#Page_178">178</a></li>
+
+  <li class="i1">Costal Cartilages,
+    <a href="#Page_51">51</a></li>
+
+  <li class="i1">Cotyloid Ligaments,
+    <a href="#Page_118">118</a></li>
+
+  <li class="i1">Coxo-femoral Articulation,
+    <a href="#Page_108">108</a></li>
+
+  <li class="i1">Cranium,
+    <a href="#Page_164">164</a></li>
+
+  <li class="i1">Cricoid Cartilage,
+    <a href="#Page_284">284</a></li>
+
+  <li class="i1">Crucial Ligaments,
+    <a href="#Page_136">136</a>,
+    <a href="#Page_141">141</a></li>
+
+  <li class="i1">Crureus Muscle,
+    <a href="#Page_261">261</a></li>
+
+  <li class="i1">Cubitus,
+    <a href="#Page_69">69</a></li>
+
+  <li class="i1">Cuboid Bone,
+    <a href="#Page_152">152</a>,
+    <a href="#Page_158">158</a></li>
+
+  <li class="i1">Cucullary Muscle,
+    <a href="#Page_208">208</a></li>
+
+  <li class="i1">Cuneiform Bones,
+    <a href="#Page_88">88</a>,
+    <a href="#Page_152">152</a>,
+    <a href="#Page_156">156</a>,
+    <a href="#Page_157">157</a></li>
+
+  <li class="i1">Curves of Vertebral Column,
+    <a href="#Page_36">36</a></li>
+</ul>
+
+<p class="p-index">D</p> 
+
+<ul>
+  <li class="i1">Darwin on Expression of Emotions,
+    <a href="#Page_304">304</a></li>
+
+  <li class="i1">Deltoid Impression,
+    <a href="#Page_68">68</a></li>
+
+  <li class="i1">Deltoid Muscle,
+    <a href="#Page_216">216</a></li>
+
+  <li class="i1">Diaphyses,
+    <a href="#Page_24">24</a></li>
+
+  <li class="i1">Digastric Muscle,
+    <a href="#Page_288">288</a>,
+    <a href="#Page_289">289</a></li>
+
+  <li class="i1">Discontent, Expression of,
+    <a href="#Page_333">333</a></li>
+
+  <li class="i1">Discs, Intervertebral,
+    <a href="#Page_34">34</a></li>
+
+  <li class="i1">Discs, Vertebral,
+    <a href="#Page_28">28</a></li>
+
+  <li class="i1">Disgust, Expression of,
+    <a href="#Page_333">333</a></li>
+
+  <li class="i1">Dissections,
+    <a href="#Page_9">9</a>,
+    <a href="#Page_12">12</a></li>
+
+  <li class="i1">Dog, Facial Angle of,
+    <a href="#Page_184">184</a></li>
+
+  <li class="i1">Dolichocephalic of Skull,
+    <a href="#Page_172">172</a></li>
+
+  <li class="i1">Dorsum Ilii,
+    <a href="#Page_106">106</a></li>
+
+  <li class="i1">Duchenne of Boulogne,
+    <a href="#Page_301">301</a>,
+    <a href="#Page_308">308</a></li>
+</ul>
+
+<p class="p-index">E</p> 
+
+<ul>
+  <li class="i1">Ear,
+    <a href="#Page_312">312</a></li>
+
+  <li class="i1">Egyptian Art,
+    <a href="#Page_2">2</a></li>
+
+  <li class="i1">Egyptian Canon,
+    <a href="#Page_99">99</a></li>
+
+  <li class="i1">Elbow, Articulation of,
+    <a href="#Page_71">71</a></li>
+
+  <li class="i1">Elbow, Hollow of,
+    <a href="#Page_234">234</a></li>
+
+  <li class="i1">Elevators of Lips, Muscles,
+    <a href="#Page_326">326</a></li>
+
+  <li class="i1">Ensiform Cartilage,
+    <a href="#Page_42">42</a></li>
+
+  <li class="i1">Epicranial Aponeurosis,
+    <a href="#Page_317">317</a></li>
+
+  <li class="i1">Epigastrium,
+    <a href="#Page_53">53</a></li>
+
+  <li class="i1">Epiphyses,
+    <a href="#Page_24">24</a></li>
+
+  <li class="i1">Erector Spinæ,
+    <a href="#Page_214">214</a></li>
+
+  <li class="i1">Expression, Antithesis of,
+    <a href="#Page_306">306</a></li>
+
+  <li class="i1">Expression, Muscles of,
+    <a href="#Page_294">294</a></li>
+
+  <li class="i1">Expressions, Combination of,
+    <a href="#Page_336">336</a></li>
+
+  <li class="i1">Extensor Brevis Digitorum,
+    <a href="#Page_279">279</a></li>
+
+  <li class="i1">Extensors of Fingers, Muscles,
+    <a href="#Page_239">239</a></li>
+
+  <li class="i1">Extensors of Toes, Muscles,
+    <a href="#Page_269">269</a></li>
+
+  <li class="i1">Eye,
+    <a href="#Page_312">312</a></li>
+
+  <li class="i1">Eye, Muscles of,
+    <a href="#Page_318">318</a></li>
+
+  <li class="i1">Eyebrow,
+    <a href="#Page_310">310</a></li>
+
+  <li class="i1">Eyelids,
+    <a href="#Page_319">319</a></li>
+</ul>
+
+<p class="p-index">F</p> 
+
+<ul>
+  <li class="i1">Face, Muscles of,
+    <a href="#Page_291">291</a>,
+    <a href="#Page_310">310</a></li>
+
+  <li class="i1">Face, Skeleton of,
+    <a href="#Page_173">173</a></li>
+
+  <li class="i1">Facial Angle,
+    <a href="#Page_181">181</a></li>
+
+  <li class="i1">Fascia Lata,
+    <a href="#Page_256">256</a></li>
+
+  <li class="i1">Female Figure, Formulæ of,
+    <a href="#Page_125">125</a></li>
+
+  <li class="i1">Femur,
+    <a href="#Page_116">116</a>,
+    <a href="#Page_131">131</a></li>
+
+  <li class="i1">Femur, Neck of,
+    <a href="#Page_117">117</a></li>
+
+  <li class="i1">Fibula,
+    <a href="#Page_135">135</a>,
+    <a href="#Page_147">147</a></li>
+
+  <li class="i1">Fingers,
+    <a href="#Page_93">93</a></li>
+
+  <li class="i1">Flexor Carpi Radialis,
+    <a href="#Page_235">235</a></li>
+
+  <li class="i1">Flexors of Fingers, Muscles,
+    <a href="#Page_237">237</a></li>
+
+  <li class="i1">Flexors of Toes, Muscles,
+    <a href="#Page_278">278</a></li>
+
+  <li class="i1">Foot,
+    <a href="#Page_151">151</a>,
+    <a href="#Page_155">155</a>,
+    <a href="#Page_160">160</a></li>
+
+  <li class="i1">Foot as a Canon,
+    <a href="#Page_185">185</a></li>
+
+  <li class="i1">Foot, Muscles of,
+    <a href="#Page_278">278</a></li>
+
+  <li class="i1">Foramen Magnum,
+    <a href="#Page_165">165</a></li>
+
+  <li class="i1">Forearm,
+    <a href="#Page_77">77</a></li>
+
+  <li class="i1">Forearm, Muscles of,
+    <a href="#Page_232">232</a>,
+    <a href="#Page_244">244</a></li>
+
+  <li class="i1">Forehead, Muscles of,
+    <a href="#Page_316">316</a></li>
+
+  <li class="i1">Formulæ of Male and Female Figures,
+    <a href="#Page_125">125</a></li>
+
+  <li class="i1">Frederick of Germany, Edict of,
+    <a href="#Page_12">12</a></li>
+
+  <li class="i1">Frontal Bone,
+    <a href="#Page_166">166</a></li>
+
+  <li class="i1">Frontal Muscle,
+    <a href="#Page_316">316</a></li>
+
+  <li class="i1">Frontal Sinuses,
+    <a href="#Page_168">168</a></li>
+</ul>
+
+<p class="p-index">G</p> 
+
+<ul>
+  <li class="i1">Galen,
+    <a href="#Page_9">9</a></li>
+
+  <li class="i1">Gastrocnemius Muscle,
+    <a href="#Page_273">273</a></li>
+
+  <li class="i1">Gemelli Muscles,
+    <a href="#Page_256">256</a></li>
+
+  <li class="i1">Gerdy on Canons,
+    <a href="#Page_185">185</a></li>
+
+  <li class="i1">Gladiator, Measurement of,
+    <a href="#Page_187">187</a></li>
+
+  <li class="i1">Glenoid Cavity,
+    <a href="#Page_59">59</a>,
+    <a href="#Page_180">180</a></li>
+
+  <li class="i1">Gluteal Muscles,
+    <a href="#Page_252">252</a></li>
+
+  <li class="i1">Gracilis,
+    <a href="#Page_264">264</a></li>
+
+  <li class="i1">Grecian Art,
+    <a href="#Page_3">3</a></li>
+
+  <li class="i1">Grief, Muscle of,
+    <a href="#Page_326">326</a></li>
+
+  <li class="i1">Grinning, Expression of,
+    <a href="#Page_334">334</a></li>
+
+  <li class="i1">Groin, Fold of,
+    <a href="#Page_112">112</a></li>
+
+  <li class="i1">Groove, Bicipital,
+    <a href="#Page_61">61</a>,
+    <a href="#Page_67">67</a></li>
+
+  <li class="i1">Gullet,
+    <a href="#Page_284">284</a></li>
+
+  <li class="i1">Gymnasium and Anatomy,
+    <a href="#Page_11">11</a></li>
+</ul>
+
+<p class="p-index">H</p>
+ 
+<ul>
+  <li class="i1">Hamstring Muscles,
+    <a href="#Page_265">265</a></li>
+
+  <li class="i1">Hand,
+    <a href="#Page_87">87</a></li>
+
+  <li class="i1">Hand, Muscles of,
+    <a href="#Page_232">232</a>,
+    <a href="#Page_247">247</a></li>
+
+  <li class="i1">Head as a Canon,
+    <a href="#Page_185">185</a></li>
+
+  <li class="i1">Head, Bones of,
+    <a href="#Page_164">164</a></li>
+
+  <li class="i1">Head, Movements of,
+    <a href="#Page_33">33</a></li>
+
+  <li class="i1">Head, Muscles of,
+    <a href="#Page_291">291</a></li>
+
+  <li class="i1">Hip-bones,
+    <a href="#Page_105">105</a></li>
+
+  <li class="i1">Hip-joint,
+    <a href="#Page_118">118</a></li>
+
+  <li class="i1">Hips, Measurements and Proportions of,
+    <a href="#Page_124">124</a></li>
+
+  <li class="i1">Humerus,
+    <a href="#Page_60">60</a>,
+    <a href="#Page_67">67</a></li>
+
+  <li class="i1">Hypothenar Eminence,
+    <a href="#Page_248">248</a>,
+    <a href="#Page_249">249</a></li>
+</ul>
+
+<p class="p-index">I</p> 
+
+<ul>
+  <li class="i1">Iliac Fossa,
+    <a href="#Page_108">108</a></li>
+
+  <li class="i1">Ilio-costalis Muscle,
+    <a href="#Page_214">214</a></li>
+
+  <li class="i1">Ilio-femoral Articulation,
+    <a href="#Page_118">118</a></li>
+
+  <li class="i1">Ilio-femoral Ligament,
+    <a href="#Page_119">119</a></li>
+
+  <li class="i1">Ilio-lumbar Ligament,
+    <a href="#Page_111">111</a></li>
+
+  <li class="i1">Ilio-pectineal Line,
+    <a href="#Page_107">107</a></li>
+
+  <li class="i1">Ilio-tibial Band,
+    <a href="#Page_144">144</a>,
+    <a href="#Page_257">257</a></li>
+
+  <li class="i1">Ilio-trochanteric Band,
+    <a href="#Page_121">121</a></li>
+
+  <li class="i1">Ilium,
+    <a href="#Page_105">105</a></li>
+
+  <li class="i1">Incisive Fossa,
+    <a href="#Page_176">176</a></li>
+
+  <li class="i1">Incisor Teeth,
+    <a href="#Page_179">179</a>,
+    <a href="#Page_180">180</a></li>
+
+  <li class="i1">Index, Brachial,
+    <a href="#Page_100">100</a></li>
+
+  <li class="i1">Index, Cephalic,
+    <a href="#Page_171">171</a></li>
+
+  <li class="i1">Index Finger,
+    <a href="#Page_91">91</a>,
+    <a href="#Page_246">246</a></li>
+
+  <li class="i1">Infra-hyoid Muscles,
+    <a href="#Page_285">285</a></li>
+
+  <li class="i1">Infra-orbital Foramen,
+    <a href="#Page_174">174</a></li>
+
+  <li class="i1">Infra-spinatus Muscle,
+    <a href="#Page_212">212</a>,
+    <a href="#Page_219">219</a></li>
+
+  <li class="i1">Inter-carpal Joint,
+    <a href="#Page_89">89</a></li>
+
+  <li class="i1">Inter-condyloid Notch,
+    <a href="#Page_133">133</a></li>
+
+  <li class="i1">Interosseous Ligament,
+    <a href="#Page_156">156</a></li>
+
+  <li class="i1">Interosseous Membrane,
+    <a href="#Page_147">147</a></li>
+
+  <li class="i1">Interosseous Muscles,
+    <a href="#Page_250">250</a></li>
+
+  <li class="i1">Interosseous Space,
+    <a href="#Page_80">80</a>,
+    <a href="#Page_147">147</a></li>
+
+  <li class="i1">Inter-phalangeal Articulation,
+    <a href="#Page_94">94</a></li>
+
+  <li class="i1">Ischium,
+    <a href="#Page_105">105</a></li>
+</ul>
+
+<p class="p-index">J</p> 
+
+<ul>
+  <li class="i1">Jaw, Articulation of, the,
+    <a href="#Page_180">180</a></li>
+
+  <li class="i1">Jaw, Muscles of,
+    <a href="#Page_292">292</a></li>
+</ul> 
+
+<p class="p-index">K</p> 
+
+<ul>
+  <li class="i1">Kissing, Expression of,
+    <a href="#Page_331">331</a></li>
+
+  <li class="i1">Knee, Articulation of,
+    <a href="#Page_131">131</a></li>
+
+  <li class="i1">Knee, Form of,
+    <a href="#Page_144">144</a></li>
+
+  <li class="i1">Knee, Ligaments of,
+    <a href="#Page_139">139</a></li>
+</ul>
+
+<p class="p-index">L</p> 
+
+<ul>
+  <li class="i1">Lachrymal Lake,
+    <a href="#Page_311">311</a></li>
+
+  <li class="i1">Lambdoid, Suture,
+    <a href="#Page_170">170</a></li>
+
+  <li class="i1">Laocoon, Measurement of,
+    <a href="#Page_187">187</a></li>
+
+  <li class="i1">Larynx,
+    <a href="#Page_284">284</a></li>
+
+  <li class="i1">Lasciviousness, Muscle of,
+    <a href="#Page_329">329</a></li>
+
+  <li class="i1">Latissimus Dorsi Muscle,
+    <a href="#Page_209">209</a></li>
+
+  <li class="i1">Laughter, Expression of,
+    <a href="#Page_326">326</a></li>
+
+  <li class="i1">Lavater on Physiognomy,
+    <a href="#Page_297">297</a></li>
+
+  <li class="i1">Le Brun on Studies of, Expression,
+    <a href="#Page_296">296</a></li>
+
+  <li class="i1">Leg,
+    <a href="#Page_135">135</a>,
+    <a href="#Page_146">146</a></li>
+
+  <li class="i1">Leg, Muscles of,
+    <a href="#Page_268">268</a></li>
+
+  <li class="i1">Ligamenta Subflava,
+    <a href="#Page_35">35</a></li>
+
+  <li class="i1">Ligamentum Nuchæ,
+    <a href="#Page_36">36</a></li>
+
+  <li class="i1">Ligamentum Teres,
+    <a href="#Page_116">116</a>,
+    <a href="#Page_122">122</a></li>
+
+  <li class="i1">Linea Alba,
+    <a href="#Page_198">198</a></li>
+
+  <li class="i1">Linea Aspera,
+    <a href="#Page_133">133</a></li>
+
+  <li class="i1">Linea Semilunaris,
+    <a href="#Page_199">199</a></li>
+
+  <li class="i1">Lineæ Transversæ,
+    <a href="#Page_203">203</a></li>
+
+  <li class="i1">Lips,
+    <a href="#Page_311">311</a></li>
+
+  <li class="i1">Lips, Muscles of,
+    <a href="#Page_326">326</a>,
+    <a href="#Page_330">330</a></li>
+
+  <li class="i1">Longissimus Dorsi Muscle,
+    <a href="#Page_214">214</a></li>
+
+  <li class="i1">Lumbricales Muscles,
+    <a href="#Page_237">237</a>,
+    <a href="#Page_250">250</a></li>
+
+  <li class="i1">Luzzi, Mondino di,
+    <a href="#Page_12">12</a></li>
+</ul>
+
+<p class="p-index">M</p> 
+
+<ul>
+  <li class="i1">Malar Bone,
+    <a href="#Page_176">176</a></li>
+
+  <li class="i1">Male Figure, Formulæ of,
+    <a href="#Page_125">125</a></li>
+
+  <li class="i1">Malleoli,
+    <a href="#Page_149">149</a></li>
+
+  <li class="i1">Mandible,
+    <a href="#Page_177">177</a></li>
+
+  <li class="i1">Manubrium of Sternum,
+    <a href="#Page_45">45</a></li>
+
+  <li class="i1">Masseter Muscle,
+    <a href="#Page_292">292</a></li>
+
+  <li class="i1">Masticating Muscles,
+    <a href="#Page_291">291</a></li>
+
+  <li class="i1">Mastoid Process,
+    <a href="#Page_169">169</a></li>
+
+  <li class="i1">Maxillary Bone, Inferior,
+    <a href="#Page_177">177</a></li>
+
+  <li class="i1">Maxillary Bone, Superior,
+    <a href="#Page_176">176</a></li>
+
+  <li class="i1">Menace, Expression of,
+    <a href="#Page_322">322</a></li>
+
+  <li class="i1">Mental Foramen,
+    <a href="#Page_178">178</a></li>
+
+  <li class="i1">Mental Process,
+    <a href="#Page_177">177</a></li>
+
+  <li class="i1">Mesaticephalic of Skull,
+    <a href="#Page_172">172</a></li>
+
+  <li class="i1">Metacarpo-phalangeal Articulation,
+    <a href="#Page_93">93</a></li>
+
+  <li class="i1">Metacarpus,
+    <a href="#Page_90">90</a></li>
+
+  <li class="i1">Metatarsus,
+    <a href="#Page_159">159</a></li>
+
+  <li class="i1">Michael Angelo,
+    <a href="#Page_14">14</a></li>
+
+  <li class="i1">Middle Finger,
+    <a href="#Page_91">91</a></li>
+
+  <li class="i1">Middle Finger as a Canon,
+    <a href="#Page_185">185</a></li>
+
+  <li class="i1">Modern Art,
+    <a href="#Page_5">5</a></li>
+
+  <li class="i1">Molar Teeth,
+    <a href="#Page_179">179</a></li>
+
+  <li class="i1">Mongols, Facial Angle of,
+    <a href="#Page_184">184</a></li>
+
+  <li class="i1">Monkeys, Facial Angle of,
+    <a href="#Page_184">184</a></li>
+
+  <li class="i1">Mouth,
+    <a href="#Page_312">312</a></li>
+
+  <li class="i1">Mouth, Muscles of,
+    <a href="#Page_325">325</a></li>
+
+  <li class="i1">Muscles in General,
+    <a href="#Page_189">189</a></li>
+
+  <li class="i1">Muscles, Movement of,
+    <a href="#Page_189">189</a></li>
+
+  <li class="i1">Muscles, Nomenclature of,
+    <a href="#Page_191">191</a></li>
+
+  <li class="i1">Mylo-hyoid Muscle,
+    <a href="#Page_288">288</a>,
+    <a href="#Page_290">290</a></li>
+</ul>
+
+<p class="p-index">N</p> 
+
+<ul>
+  <li class="i1">Nasal Bones,
+    <a href="#Page_168">168</a></li>
+
+  <li class="i1">Nasal Eminences,
+    <a href="#Page_168">168</a></li>
+
+  <li class="i1">Nasal Fossa,
+    <a href="#Page_175">175</a></li>
+
+  <li class="i1">Naso-labial Fold,
+    <a href="#Page_311">311</a></li>
+
+  <li class="i1">Naso-lachrymal Groove,
+    <a href="#Page_174">174</a></li>
+
+  <li class="i1">Navicular Bone,
+    <a href="#Page_152">152</a>,
+    <a href="#Page_156">156</a>,
+    <a href="#Page_158">158</a></li>
+
+  <li class="i1">Neck, Movements of,
+    <a href="#Page_282">282</a></li>
+
+  <li class="i1">Neck, Muscles of,
+    <a href="#Page_281">281</a>,
+    <a href="#Page_334">334</a></li>
+
+  <li class="i1">Neck, Region of,
+    <a href="#Page_208">208</a></li>
+
+  <li class="i1">Negro, Facial Angle of,
+    <a href="#Page_183">183</a>,
+    <a href="#Page_184">184</a></li>
+
+  <li class="i1">Neural Arch,
+    <a href="#Page_29">29</a></li>
+
+  <li class="i1">Neural Canal,
+    <a href="#Page_29">29</a></li>
+
+  <li class="i1">Nipple of, Breast,
+    <a href="#Page_196">196</a></li>
+
+  <li class="i1">Nomenclature,
+    <a href="#Page_22">22</a></li>
+
+  <li class="i1">Nose, Muscles of,
+    <a href="#Page_328">328</a></li>
+
+  <li class="i1">Nostrils,
+    <a href="#Page_312">312</a></li>
+</ul>
+
+<p class="p-index">O</p> 
+
+<ul>
+  <li class="i1">Oblique Muscles of the Abdomen,
+    <a href="#Page_198">198</a></li>
+
+  <li class="i1">Obturator Foramen,
+    <a href="#Page_106">106</a></li>
+
+  <li class="i1">Obturator Membrane,
+    <a href="#Page_111">111</a></li>
+
+  <li class="i1">Obturator Muscle,
+    <a href="#Page_256">256</a></li>
+
+  <li class="i1">Occipital Bone,
+    <a href="#Page_164">164</a></li>
+
+  <li class="i1">Occipital Condyles,
+    <a href="#Page_165">165</a></li>
+
+  <li class="i1">Occipital Muscle,
+    <a href="#Page_316">316</a></li>
+
+  <li class="i1">Odontoid Process,
+    <a href="#Page_32">32</a></li>
+
+  <li class="i1">Œsophagus,
+    <a href="#Page_284">284</a></li>
+
+  <li class="i1">Olecranon,
+    <a href="#Page_70">70</a></li>
+
+  <li class="i1">Olecranon Fossa,
+    <a href="#Page_69">69</a></li>
+
+  <li class="i1">Olecranon Process,
+    <a href="#Page_71">71</a></li>
+
+  <li class="i1">Omo-hyoid Muscle,
+    <a href="#Page_286">286</a></li>
+
+  <li class="i1">Opponens Muscles,
+    <a href="#Page_248">248</a></li>
+
+  <li class="i1">Opposition, Movements of,
+    <a href="#Page_92">92</a></li>
+
+  <li class="i1">Optic Foramen,
+    <a href="#Page_175">175</a></li>
+
+  <li class="i1">Orbicular Muscle of Eyelids,
+    <a href="#Page_318">318</a></li>
+
+  <li class="i1">Orbicular Muscle of Lips,
+    <a href="#Page_330">330</a></li>
+
+  <li class="i1">Orbicularis Palpebrarum,
+    <a href="#Page_318">318</a></li>
+
+  <li class="i1">Orbital Processes,
+    <a href="#Page_176">176</a></li>
+
+  <li class="i1">Orbits,
+    <a href="#Page_173">173</a></li>
+
+  <li class="i1">Os Calcis,
+    <a href="#Page_152">152</a></li>
+
+  <li class="i1">Os Magnum,
+    <a href="#Page_88">88</a></li>
+
+  <li class="i1">Ossa Innominata,
+    <a href="#Page_105">105</a></li>
+
+  <li class="i1">Osteology,
+    <a href="#Page_19">19</a></li>
+</ul>
+
+<p class="p-index">P</p> 
+
+<ul>
+  <li class="i1">Pain, Expression of,
+    <a href="#Page_335">335</a></li>
+
+  <li class="i1">Palmar Fascia,
+    <a href="#Page_248">248</a></li>
+
+  <li class="i1">Palmaris Brevis,
+    <a href="#Page_249">249</a></li>
+
+  <li class="i1">Palmaris Longus,
+    <a href="#Page_235">235</a></li>
+
+  <li class="i1">Palpebral Muscle,
+    <a href="#Page_318">318</a></li>
+
+  <li class="i1">Panniculus Carnosus,
+    <a href="#Page_313">313</a></li>
+
+  <li class="i1">Parietal Bones,
+    <a href="#Page_166">166</a></li>
+
+  <li class="i1">Patella,
+    <a href="#Page_134">134</a></li>
+
+  <li class="i1">Patella, Ligament of,
+    <a href="#Page_142">142</a>,
+    <a href="#Page_260">260</a></li>
+
+  <li class="i1">Patellar Surface,
+    <a href="#Page_133">133</a></li>
+
+  <li class="i1">Pectineus Muscle,
+    <a href="#Page_262">262</a></li>
+
+  <li class="i1">Pectoral Muscles,
+    <a href="#Page_193">193</a></li>
+
+  <li class="i1">Pelvis,
+    <a href="#Page_103">103</a></li>
+
+  <li class="i1">Pelvis, Muscles of,
+    <a href="#Page_252">252</a></li>
+
+  <li class="i1">Perineum,
+    <a href="#Page_112">112</a></li>
+
+  <li class="i1">Peroneal Muscles,
+    <a href="#Page_158">158</a>,
+    <a href="#Page_160">160</a>,
+    <a href="#Page_271">271</a></li>
+
+  <li class="i1">Petrous Portion,
+    <a href="#Page_168">168</a></li>
+
+  <li class="i1">Phalanges of Fingers,
+    <a href="#Page_93">93</a></li>
+
+  <li class="i1">Phalanges of Toes,
+    <a href="#Page_160">160</a></li>
+
+  <li class="i1">Pharynx,
+    <a href="#Page_284">284</a></li>
+
+  <li class="i1">Philtrum,
+    <a href="#Page_311">311</a></li>
+
+  <li class="i1">Physiology,
+    <a href="#Page_9">9</a></li>
+
+  <li class="i1">Pinna,
+    <a href="#Page_312">312</a></li>
+
+  <li class="i1">Pisiform Bone,
+    <a href="#Page_88">88</a></li>
+
+  <li class="i1">Plantar Ligaments,
+    <a href="#Page_156">156</a></li>
+
+  <li class="i1">Plantaris Muscle,
+    <a href="#Page_277">277</a></li>
+
+  <li class="i1">Platysma Muscles,
+    <a href="#Page_211">211</a></li>
+
+  <li class="i1">Platysma of Neck,
+    <a href="#Page_334">334</a></li>
+
+  <li class="i1">Plica Semilunaris,
+    <a href="#Page_311">311</a></li>
+
+  <li class="i1">Pomum Adami,
+    <a href="#Page_284">284</a></li>
+
+  <li class="i1">Popliteal Space,
+    <a href="#Page_142">142</a></li>
+
+  <li class="i1">Posterior Triangle,
+    <a href="#Page_210">210</a></li>
+
+  <li class="i1">Poupart’s Ligament,
+    <a href="#Page_111">111</a></li>
+
+  <li class="i1">Pouting, Expression of,
+    <a href="#Page_331">331</a></li>
+
+  <li class="i1">Processes of Vertebræ,
+    <a href="#Page_30">30</a></li>
+
+  <li class="i1">Pronation,
+    <a href="#Page_82">82</a></li>
+
+  <li class="i1">Pronator Quadratus,
+    <a href="#Page_237">237</a></li>
+
+  <li class="i1">Pronator Radii Teres, Impression for,
+    <a href="#Page_78">78</a></li>
+
+  <li class="i1">Pronator Teres,
+    <a href="#Page_233">233</a></li>
+
+  <li class="i1">Proportion of Arm,
+    <a href="#Page_97">97</a></li>
+
+  <li class="i1">Proportion of Clavicle,
+    <a href="#Page_46">46</a></li>
+
+  <li class="i1">Proportion of Foot,
+    <a href="#Page_163">163</a></li>
+
+  <li class="i1">Proportion of Hips,
+    <a href="#Page_124">124</a></li>
+
+  <li class="i1">Proportion of Leg,
+    <a href="#Page_162">162</a></li>
+
+  <li class="i1">Proportion of Lower Limb,
+    <a href="#Page_161">161</a></li>
+
+  <li class="i1">Proportion of Pelvis,
+    <a href="#Page_114">114</a></li>
+
+  <li class="i1">Proportion of Sternum,
+    <a href="#Page_46">46</a></li>
+
+  <li class="i1">Proportion of Upper Limb,
+    <a href="#Page_96">96</a></li>
+
+  <li class="i1">Proportion of Vertebral Column,
+    <a href="#Page_38">38</a></li>
+
+  <li class="i1">Psoas Muscle,
+    <a href="#Page_263">263</a></li>
+
+  <li class="i1">Pterygoid Muscle,
+    <a href="#Page_292">292</a></li>
+
+  <li class="i1">Pubis,
+    <a href="#Page_105">105</a></li>
+
+  <li class="i1">Pyramidalis Abdominis Muscle,
+    <a href="#Page_204">204</a></li>
+
+  <li class="i1">Pyramidalis Muscle of Face,
+    <a href="#Page_322">322</a></li>
+
+  <li class="i1">Pyriformis Muscle,
+    <a href="#Page_256">256</a></li>
+</ul>
+
+<p class="p-index">Q</p> 
+
+<ul>
+  <li class="i1">Quadratus Femoris,
+    <a href="#Page_256">256</a></li>
+
+  <li class="i1">Quadratus Menti,
+    <a href="#Page_333">333</a></li>
+
+  <li class="i1">Quadriceps Extensor Muscle,
+    <a href="#Page_259">259</a></li>
+
+  <li class="i1">Quadrumana,
+    <a href="#Page_148">148</a></li>
+</ul>
+
+<p class="p-index">R</p> 
+
+<ul>
+  <li class="i1">Radial Head,
+    <a href="#Page_68">68</a></li>
+
+  <li class="i1">Radial Muscles,
+    <a href="#Page_239">239</a></li>
+
+  <li class="i1">Radio-carpal Articulation,
+    <a href="#Page_78">78</a></li>
+
+  <li class="i1">Radio-carpal Joint,
+    <a href="#Page_89">89</a></li>
+
+  <li class="i1">Radio-ulnar Articulation,
+    <a href="#Page_82">82</a></li>
+
+  <li class="i1">Radius,
+    <a href="#Page_70">70</a>,
+    <a href="#Page_77">77</a></li>
+
+  <li class="i1">Ramus of Lower Jaw,
+    <a href="#Page_178">178</a></li>
+
+  <li class="i1">Rectus Abdominis,
+    <a href="#Page_202">202</a></li>
+
+  <li class="i1">Rectus Femoris,
+    <a href="#Page_259">259</a></li>
+
+  <li class="i1">Reflection, Expression of,
+    <a href="#Page_320">320</a></li>
+
+  <li class="i1">Renaissance Art,
+    <a href="#Page_4">4</a></li>
+
+  <li class="i1">Rhomboid Muscles,
+    <a href="#Page_212">212</a></li>
+
+  <li class="i1">Ribs,
+    <a href="#Page_46">46</a></li>
+
+  <li class="i1">Risorius Muscle of Santorini,
+    <a href="#Page_334">334</a></li>
+
+  <li class="i1">Roman Art,
+    <a href="#Page_4">4</a></li>
+</ul>
+
+<p class="p-index">S</p> 
+
+<ul>
+  <li class="i1">Sacro-sciatic Ligaments,
+    <a href="#Page_105">105</a>,
+    <a href="#Page_111">111</a></li>
+
+  <li class="i1">Sacrum,
+    <a href="#Page_103">103</a></li>
+
+  <li class="i1">Sadness, Expression of,
+    <a href="#Page_332">332</a></li>
+
+  <li class="i1">Sagittal Suture,
+    <a href="#Page_170">170</a></li>
+
+  <li class="i1">Salvage and Malgaigne’s Formula,
+    <a href="#Page_125">125</a></li>
+
+  <li class="i1">Sappey, Professor, on Canons,
+    <a href="#Page_188">188</a></li>
+
+  <li class="i1">Sartorius Muscle,
+    <a href="#Page_258">258</a></li>
+
+  <li class="i1">Scaphoid Bone,
+    <a href="#Page_88">88</a>,
+    <a href="#Page_152">152</a>,
+    <a href="#Page_156">156</a>,
+    <a href="#Page_158">158</a></li>
+
+  <li class="i1">Scapula,
+    <a href="#Page_56">56</a></li>
+
+  <li class="i1">Scapulo-humeral Articulation,
+    <a href="#Page_60">60</a>,
+    <a href="#Page_61">61</a></li>
+
+  <li class="i1">Scarpa’s Triangle,
+    <a href="#Page_263">263</a></li>
+
+  <li class="i1">Sciatic Notch,
+    <a href="#Page_109">109</a></li>
+
+  <li class="i1">Scorn, Expression of,
+    <a href="#Page_333">333</a></li>
+
+  <li class="i1">Semi-lunar Bone,
+    <a href="#Page_88">88</a></li>
+
+  <li class="i1">Semi-lunar Fascia,
+    <a href="#Page_225">225</a></li>
+
+  <li class="i1">Semi-lunar Ligaments,
+    <a href="#Page_137">137</a></li>
+
+  <li class="i1">Semi-membranosus Muscle,
+    <a href="#Page_267">267</a></li>
+
+  <li class="i1">Semi-tendinosus Muscle,
+    <a href="#Page_266">266</a></li>
+
+  <li class="i1">Serratus Magnus Muscle,
+    <a href="#Page_215">215</a>,
+    <a href="#Page_220">220</a></li>
+
+  <li class="i1">Sexes, Formulæ of,
+    <a href="#Page_125">125</a></li>
+
+  <li class="i1">Shin Bone,
+    <a href="#Page_135">135</a></li>
+
+  <li class="i1">Shoulder,
+    <a href="#Page_55">55</a></li>
+
+  <li class="i1">Shoulder Blade,
+    <a href="#Page_56">56</a></li>
+
+  <li class="i1">Shoulder Joint,
+    <a href="#Page_61">61</a></li>
+
+  <li class="i1">Shoulder, Muscles of,
+    <a href="#Page_215">215</a></li>
+
+  <li class="i1">Sigmoid Cavities,
+    <a href="#Page_70">70</a></li>
+
+  <li class="i1">Sigmoid Notch,
+    <a href="#Page_178">178</a></li>
+
+  <li class="i1">Skeleton, Subdivisions of,
+    <a href="#Page_27">27</a></li>
+
+  <li class="i1">Skin, Muscles of,
+    <a href="#Page_292">292</a></li>
+
+  <li class="i1">Skull,
+    <a href="#Page_164">164</a></li>
+
+  <li class="i1">Sobbing, Muscle of,
+    <a href="#Page_328">328</a></li>
+
+  <li class="i1">Sole of Foot,
+    <a href="#Page_151">151</a>,
+    <a href="#Page_160">160</a>,
+    <a href="#Page_278">278</a></li>
+
+  <li class="i1">Soleus Muscle,
+    <a href="#Page_276">276</a></li>
+
+  <li class="i1">Sorrow, Expression of,
+    <a href="#Page_332">332</a></li>
+
+  <li class="i1">Sphenoid Bone,
+    <a href="#Page_170">170</a></li>
+
+  <li class="i1">Sphenoidal Fissure,
+    <a href="#Page_175">175</a></li>
+
+  <li class="i1">Spinal Crest,
+    <a href="#Page_37">37</a></li>
+
+  <li class="i1">Spinous Processes,
+    <a href="#Page_30">30</a></li>
+
+  <li class="i1">Spiral Groove,
+    <a href="#Page_68">68</a></li>
+
+  <li class="i1">Splenius Muscle,
+    <a href="#Page_211">211</a></li>
+
+  <li class="i1">Spring Ligament,
+    <a href="#Page_157">157</a></li>
+
+  <li class="i1">Sterno-cleido-mastoid Muscle,
+    <a href="#Page_281">281</a></li>
+
+  <li class="i1">Sterno-hyoid Muscle,
+    <a href="#Page_287">287</a></li>
+
+  <li class="i1">Sterno-thyroid Muscle,
+    <a href="#Page_287">287</a></li>
+
+  <li class="i1">Sternum,
+    <a href="#Page_41">41</a></li>
+
+  <li class="i1">Stomach, Pit of,
+    <a href="#Page_53">53</a></li>
+
+  <li class="i1">Stylo-hyoid Muscle,
+    <a href="#Page_287">287</a>,
+    <a href="#Page_289">289</a></li>
+
+  <li class="i1">Styloid Process,
+    <a href="#Page_79">79</a>,
+    <a href="#Page_136">136</a>,
+    <a href="#Page_169">169</a></li>
+
+  <li class="i1">Subscapularis Muscle,
+    <a href="#Page_220">220</a></li>
+
+  <li class="i1">Sue on Physiognomy,
+    <a href="#Page_297">297</a></li>
+
+  <li class="i1">Superciliary Muscle,
+    <a href="#Page_323">323</a></li>
+
+  <li class="i1">Superville, Humbert de,
+    <a href="#Page_298">298</a></li>
+
+  <li class="i1">Supination,
+    <a href="#Page_80">80</a></li>
+
+  <li class="i1">Supinator Muscles,
+    <a href="#Page_238">238</a></li>
+
+  <li class="i1">Supinator Radii Brevis,
+    <a href="#Page_239">239</a></li>
+
+  <li class="i1">Supra-condyloid Ridge,
+    <a href="#Page_69">69</a></li>
+
+  <li class="i1">Supra-hyoid Muscles,
+    <a href="#Page_287">287</a></li>
+
+  <li class="i1">Supra-orbital Arches,
+    <a href="#Page_168">168</a></li>
+
+  <li class="i1">Supra-spinatus Muscle,
+    <a href="#Page_215">215</a>,
+    <a href="#Page_219">219</a></li>
+
+  <li class="i1">Sustentaculum Tali,
+    <a href="#Page_155">155</a></li>
+
+  <li class="i1">Sutures of Skull,
+    <a href="#Page_170">170</a></li>
+
+  <li class="i1">Symphyses, Sacro-iliac,
+    <a href="#Page_110">110</a></li>
+
+  <li class="i1">Symphysis of Pubis,
+    <a href="#Page_110">110</a></li>
+</ul>
+
+<p class="p-index">T</p> 
+
+<ul>
+  <li class="i1">Talus Bone,
+    <a href="#Page_152">152</a></li>
+
+  <li class="i1">Tarsus,
+    <a href="#Page_151">151</a>,
+    <a href="#Page_155">155</a>,
+    <a href="#Page_279">279</a></li>
+
+  <li class="i1">Teeth,
+    <a href="#Page_179">179</a></li>
+
+  <li class="i1">Temporal Bones,
+    <a href="#Page_168">168</a></li>
+
+  <li class="i1">Temporal Fossa,
+    <a href="#Page_170">170</a></li>
+
+  <li class="i1">Temporal Muscle,
+    <a href="#Page_293">293</a></li>
+
+  <li class="i1">Temporal Ridge,
+    <a href="#Page_166">166</a></li>
+
+  <li class="i1">Temporo-maxillary Articulation,
+    <a href="#Page_180">180</a></li>
+
+  <li class="i1">Tendo Achillis,
+    <a href="#Page_277">277</a></li>
+
+  <li class="i1">Tendons in General,
+    <a href="#Page_190">190</a></li>
+
+  <li class="i1">Tensor of Fascia Lata,
+    <a href="#Page_256">256</a></li>
+
+  <li class="i1">Teres Muscles,
+    <a href="#Page_212">212</a></li>
+
+  <li class="i1">Thenar Eminence,
+    <a href="#Page_248">248</a></li>
+
+  <li class="i1">Thigh,
+    <a href="#Page_116">116</a></li>
+
+  <li class="i1">Thigh, Muscles of,
+    <a href="#Page_256">256</a></li>
+
+  <li class="i1">Thorax,
+    <a href="#Page_41">41</a>,
+    <a href="#Page_51">51</a></li>
+
+  <li class="i1">Threatening Expression,
+    <a href="#Page_335">335</a></li>
+
+  <li class="i1">Thyro-hyoid Muscle,
+    <a href="#Page_287">287</a></li>
+
+  <li class="i1">Thyroid Body,
+    <a href="#Page_285">285</a></li>
+
+  <li class="i1">Thyroid Cartilage,
+    <a href="#Page_284">284</a></li>
+
+  <li class="i1">Thyroid Foramen,
+    <a href="#Page_106">106</a></li>
+
+  <li class="i1">Thumb,
+    <a href="#Page_91">91</a></li>
+
+  <li class="i1">Tibia,
+    <a href="#Page_135">135</a>,
+    <a href="#Page_146">146</a></li>
+
+  <li class="i1">Tibia, Tubercle of,
+    <a href="#Page_144">144</a></li>
+
+  <li class="i1">Tibialis Anticus,
+    <a href="#Page_268">268</a></li>
+
+  <li class="i1">Tibialis Posticus,
+    <a href="#Page_278">278</a></li>
+
+  <li class="i1">Tibio-astragaloid Articulation,
+    <a href="#Page_153">153</a></li>
+
+  <li class="i1">Tibio-fibular Articulation,
+    <a href="#Page_148">148</a></li>
+
+  <li class="i1">Titian and Andreas Vesalius,
+    <a href="#Page_14">14</a></li>
+
+  <li class="i1">Toes,
+    <a href="#Page_151">151</a></li>
+
+  <li class="i1">Toes, Muscles of,
+    <a href="#Page_269">269</a></li>
+
+  <li class="i1">Tongue,
+    <a href="#Page_284">284</a></li>
+
+  <li class="i1">Trachea,
+    <a href="#Page_284">284</a></li>
+
+  <li class="i1">Transversalis Muscles,
+    <a href="#Page_202">202</a></li>
+
+  <li class="i1">Trapezium,
+    <a href="#Page_88">88</a></li>
+
+  <li class="i1">Trapezius Muscle,
+    <a href="#Page_205">205</a></li>
+
+  <li class="i1">Trapezoid Bone,
+    <a href="#Page_88">88</a></li>
+
+  <li class="i1">Trapezoid Ligament,
+    <a href="#Page_59">59</a></li>
+
+  <li class="i1">Triangular Fibro-cartilage of Wrist,
+    <a href="#Page_79">79</a></li>
+
+  <li class="i1">Triangular Ligament of Hip-Bone,
+    <a href="#Page_111">111</a></li>
+
+  <li class="i1">Triceps Muscle,
+    <a href="#Page_223">223</a>,
+    <a href="#Page_229">229</a></li>
+
+  <li class="i1">Trochanters,
+    <a href="#Page_116">116</a>,
+    <a href="#Page_129">129</a></li>
+
+  <li class="i1">Trochlea,
+    <a href="#Page_68">68</a>,
+    <a href="#Page_71">71</a></li>
+
+  <li class="i1">Trunk, Muscles of,
+    <a href="#Page_192">192</a></li>
+</ul>
+
+<p class="p-index">U</p> 
+
+<ul>
+  <li class="i1">Ulna,
+    <a href="#Page_69">69</a>,
+    <a href="#Page_77">77</a></li>
+
+  <li class="i1">Unciform Bone,
+    <a href="#Page_88">88</a></li>
+</ul> 
+
+<p class="p-index">V</p>
+ 
+<ul>
+  <li class="i1">Vasti Muscles,
+    <a href="#Page_260">260</a></li>
+
+  <li class="i1">Vertebra,
+    <a href="#Page_29">29</a></li>
+
+  <li class="i1">Vertebra Prominens,
+    <a href="#Page_33">33</a></li>
+
+  <li class="i1">Vertebral Column,
+    <a href="#Page_27">27</a></li>
+
+  <li class="i1">Vertebral Furrow,
+    <a href="#Page_37">37</a></li>
+
+  <li class="i1">Vesalius, Andreas,
+    <a href="#Page_14">14</a></li>
+
+  <li class="i1">Vinci, Leonardo da,
+    <a href="#Page_13">13</a>,
+    <a href="#Page_295">295</a></li>
+</ul>
+
+<p class="p-index">W</p> 
+
+<ul>
+  <li class="i1">Weeping, Muscle of,
+    <a href="#Page_328">328</a></li>
+
+  <li class="i1">Windpipe,
+    <a href="#Page_284">284</a></li>
+
+  <li class="i1">Wrist,
+    <a href="#Page_87">87</a></li>
+
+  <li class="i1">Wrist Joint,
+    <a href="#Page_89">89</a></li>
+
+  <li class="i1">Wrist, Muscles of,
+    <a href="#Page_239">239</a></li>
+</ul>
+
+<p class="p-index">X</p> 
+
+<ul>
+  <li class="i1">Xiphoid Cartilage,
+    <a href="#Page_42">42</a></li>
+</ul> 
+
+<p class="p-index">Y</p>
+
+<ul>
+  <li class="i1"><img src="images/thick_y.jpg" alt=""
+style="height:.8em;  padding:0 0em 0 0em;">-shaped Ligament of Bigelow,
+    <a href="#Page_119">119</a></li>
+</ul>
+ 
+<p class="p-index">Z</p>
+
+<ul>
+  <li class="i1">Zona Circularis,
+    <a href="#Page_119">119</a></li>
+
+  <li class="i1">Zygomatic Arch,
+    <a href="#Page_169">169</a>,
+    <a href="#Page_176">176</a></li>
+
+  <li class="i1">Zygomatic Muscles,
+    <a href="#Page_324">324</a></li>
+
+  <li class="i1">Zygomatic Process,
+    <a href="#Page_169">169</a>,
+    <a href="#Page_176">176</a></li>
+</ul>
+
+
+<p class="center p2 xs">PRINTED BY CASSELL AND COMPANY, LIMITED, LA BELLE SAUVAGE, LONDON,
+E.C.4 15719</p>
+
+
+<div class="footnotes"><h2>FOOTNOTES:</h2>
+
+<div class="footnote">
+
+<p><a id="Footnote_1" href="#FNanchor_1" class="label">[1]</a> P. N. Gerdy: “Anatomy of the Forms of the Human Body for
+Painting, Sculpture, and Surgery.” Paris, 1829.</p>
+
+</div>
+
+<div class="footnote">
+
+<p><a id="Footnote_2" href="#FNanchor_2" class="label">[2]</a> It is not always thus abroad. Thus in Germany there is the
+work of E. Harless (“Lehrbuch der Plastischen Anatomie für Akademische
+Anstalten.” Stuttgart, 1876: 2nd edit.).</p>
+
+</div>
+
+<div class="footnote">
+
+<p><a id="Footnote_3" href="#FNanchor_3" class="label">[3]</a> We must look for other reasons than ignorance or
+indifference to explain the fixed scapulæ in pre-Phidian sculpture,
+or the exaggerated forms given to the extensor brevis of the foot
+and other muscles. This qualification is necessary to this general
+statement.—<span class="smcap">Ed.</span></p>
+
+</div>
+
+<div class="footnote">
+
+<p><a id="Footnote_4" href="#FNanchor_4" class="label">[4]</a> See Ludwig Choulant. <i>Gesichte und Bibliographie des
+Anatomischen Abbildungen.</i> Leipzig: 1852. (A very curious work
+wherein is found much information respecting the connection of anatomy
+with the plastic arts.)</p>
+
+</div>
+
+<div class="footnote">
+
+<p><a id="Footnote_5" href="#FNanchor_5" class="label">[5]</a> Seroux d’Agincourt. <i>History of Art by its
+Monuments.</i> Paris: 1811. Vol. i., p. 177.</p>
+
+</div>
+
+<div class="footnote">
+
+<p><a id="Footnote_6" href="#FNanchor_6" class="label">[6]</a> Pierre Camper. “Dissertations sur les différences rúlles
+que présentent les traits du visage chez les hommes de différents pays
+et de différent âges.” (Œuvres posthumes. Paris, 1786.)</p>
+
+</div>
+
+<div class="footnote">
+
+<p><a id="Footnote_7" href="#FNanchor_7" class="label">[7]</a> See especially; <i>Conférences sur l’expression des
+differents charactères des passions</i>, Paris, 1667. (These essays
+have been reprinted in the edition of Lavater, by Moreau. Vol. ix.,
+1820.)</p>
+
+</div>
+
+<div class="footnote">
+
+<p><a id="Footnote_8" href="#FNanchor_8" class="label">[8]</a> <i>The Anatomy and Physiology of Expression</i> (3rd
+edition, 1884, published after the death of Sir Charles Bell, and
+containing his last corrections.)</p>
+
+</div>
+
+<div class="footnote">
+
+<p><a id="Footnote_9" href="#FNanchor_9" class="label">[9]</a> The edition to consult is that issued in 1820, in ten
+volumes, by Moreau.</p>
+
+</div>
+
+<div class="footnote">
+
+<p><a id="Footnote_10" href="#FNanchor_10" class="label">[10]</a> Charles Darwin. <i>The Expression of the Emotions in Man
+and in Animals.</i></p>
+
+</div>
+
+<div class="footnote">
+
+<p><a id="Footnote_11" href="#FNanchor_11" class="label">[11]</a> Albert Lemoine: <i>De la Physionomie et de la Parole</i>.
+Paris, 1865. Pierre Gratiolet: <i>De la Physionomie et des Mouvements
+d’Expression</i>. Paris, 1865. Piderit: <i>Wissenschaftliches System
+der Mimik und Physiognomik</i>. 1867.</p>
+
+</div>
+</div>
+
+
+<p class="transnote">Transcriber’s Notes:<br>
+<br>
+1. Obvious printers’, punctuation and spelling errors have been
+corrected silently.<br>
+<br>
+2. Some hyphenated and non-hyphenated versions of the same words have
+been retained as in the original.</p>
+
+
+<div style='text-align:center'>*** END OF THE PROJECT GUTENBERG EBOOK 77743 ***</div>
+</body>
+</html>
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diff --git a/LICENSE.txt b/LICENSE.txt
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+++ b/LICENSE.txt
@@ -0,0 +1,11 @@
+This book, including all associated images, markup, improvements,
+metadata, and any other content or labor, has been confirmed to be
+in the PUBLIC DOMAIN IN THE UNITED STATES.
+
+Procedures for determining public domain status are described in
+the "Copyright How-To" at https://www.gutenberg.org.
+
+No investigation has been made concerning possible copyrights in
+jurisdictions other than the United States. Anyone seeking to utilize
+this eBook outside of the United States should confirm copyright
+status under the laws that apply to them.
diff --git a/README.md b/README.md
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@@ -0,0 +1,2 @@
+Project Gutenberg (https://www.gutenberg.org) public repository for eBook #77743
+(https://www.gutenberg.org/ebooks/77743)
author	www-data <www-data@mail.pglaf.org>	2026-01-20 04:09:45 -0800
committer	www-data <www-data@mail.pglaf.org>	2026-01-20 04:09:45 -0800
commit	52618285117ccefd76a96a4997a129552b0c70f3 (patch)
tree	cb5e6329a45a1b9e152392356f979081b7c6cf8f