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diff --git a/77743-h/77743-h.htm b/77743-h/77743-h.htm new file mode 100644 index 0000000..7fa5b58 --- /dev/null +++ b/77743-h/77743-h.htm @@ -0,0 +1,11753 @@ +<!DOCTYPE html> +<html lang="en"> +<head> + <meta charset="UTF-8"> + <title> + Duval’s Artistic Anatomy | Project Gutenberg + </title> + <link rel="icon" href="images/cover.jpg" type="image/x-cover"> + <style> + +body { + margin-left: 10%; + margin-right: 10%; +} + + h1,h2,h3{ + text-align: center; /* all headings centered */ + clear: both; + font-weight: normal; +} + +h2 {font-size: 100%;} + +h3 {font-size: 80%;} + +.subhed { display: block; margin-top: .5em; font-size: 80%; font-weight: normal; } + +p { + margin-top: .51em; + text-align: justify; + margin-bottom: .49em; + text-indent: 1.2em; +} + +.p0 {margin-top: 0em;} +.p1 {margin-top: 1em;} +.p2 {margin-top: 2em;} +.p4 {margin-top: 4em;} + +.p-index {text-indent: 8em; } + +hr { + width: 33%; + margin-top: 2em; + margin-bottom: 2em; + margin-left: 33.5%; + margin-right: 33.5%; + clear: both; +} + +hr.chap {width: 65%; margin-left: 17.5%; margin-right: 17.5%;} + +hr.r25 {width: 25%; margin-top: 1em; margin-bottom: 1em; margin-left: 37.5%; margin-right: 37.5%;} + +div.chapter {page-break-before: always;} + +ul { list-style-type: none; } +li.i1 { + text-indent: -2em; + padding-left: 2em; +} + +table { +margin: auto; +width:auto; +border: 0; +border-spacing: 0; +border-collapse: collapse; } + +td { +padding: 0em .2em 0em 2.5em; +border: .1em none white; +text-align: left; +text-indent: -2em; } + +th.chap { +font-weight: normal; +font-size: x-small; +text-align: right; +padding-left: 1em; } + +th.pag { +font-weight: normal; +font-size: x-small; +text-align: right; +padding-left: 2em; } + +th.header { +padding: 1.5em .2em .2em .2em; +text-align: center; +text-indent: 0em; +font-size: 100%; +font-weight: normal;} + +td.chn { +text-align: right; +vertical-align: top; +padding-right: 1em; } + +td.cht { +text-align: left; +vertical-align: top; +padding-left: 1.5em; +text-indent: -1em;} + +td.pag { +text-align: right; +vertical-align: bottom; +padding-left: 2em;} + +.pagenum { /* uncomment the next line for invisible page numbers */ + /* visibility: hidden; */ + position: absolute; + left: 92%; + font-size: small; + text-align: right; + font-style: normal; + font-weight: normal; + font-variant: normal; + text-indent: 0; +} /* page numbers */ + +.blockquot { + margin-left: 5%; + margin-right: 10%; + font-size: 90%; +} + +.hangingindent { + padding-left: 2em ; + text-indent: -2em ;} + +.xs { font-size: x-small;} + +.sm { font-size: small;} + +.lg { font-size: large;} + +.xl { font-size: x-large;} + +.smaller {font-size: 90%; } + +.center {text-align: center; + text-indent: 0em;} + +.r2 {text-align: right; + margin-right: 2em;} + +.smcap {font-variant: small-caps;} + +.allsmcap {font-variant: small-caps; text-transform: lowercase;} + +/* Images */ + +img { + max-width: 100%; + height: auto; +} + +.figcenter { + margin: auto; + text-align: center; + page-break-inside: avoid; + max-width: 100%; +} + +/* Footnotes */ +.footnotes {border: 1px dashed;} + +.footnote {margin-left: 10%; margin-right: 10%; font-size: 0.9em;} + +.footnote .label {position: absolute; right: 84%; text-align: right;} + +.fnanchor { + vertical-align: super; + font-size: .8em; + text-decoration: + none; +} + +/* Transcriber's notes */ +.transnote {background-color: #E6E6FA; + color: black; + font-size:small; + padding:0.5em; + margin-bottom:5em; + font-family:sans-serif, serif; +} + + </style> +</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 & 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, &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, &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, +&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,” &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, &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, +&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>, &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>, &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>, &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, &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.    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), &c., &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>&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, &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, &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, &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>, &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, &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>, &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.   Fig. 91.   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, &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, &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, &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, &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> |