au . a Sah) SO Suis i i Ren il an a ae “ A a x ne ‘ a ya hie aan Mea x i Pale CORNELL UNIVERSITY. THE KHoswell PP. Flower Library THE GIFT OF ROSWELL P. FLOWER FOR THE USE OF THE N. Y. STATE VETERINARY COLLEGE. 1897 The comparative an Ml atomy of the domestica Cornell University The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924000012389 THE COMPARATIVE ANATOMY OF THE DOMESTICATED ANIMALS. er By AY’;CHAUVEAU, PROFESSOR AT THE LYONS VETERINARY SCHOOL. Second Edition, Rebised and Gnlarged, with the Go-operution of 8. ARLOING, LATE PRINCIPAL OF ANATOMY AT THE LYONS VETERINARY SCHOOL; PROFESSOR AT TIE TOULOUSE VETERINARY SCILOOL. TRANSLATED AND EDITED BY @ GEORGE FLEMING, F.R.G.8. M A.L, t VETERINARY SURGEON, ROYAL- ENGINEERS, AUTHOR OF “TRAVELS ON HORSEBACK IN MANTCHU TARTARY,"' HORSE-8AOES AND HORSE-SHOEING, “ ANIMAL PLAGUES,” “PRACTICAL HORSE-SHORING;” “RABIES AND HYD ROPHOBIA,” ETO. 7 ” WITH 4850 ILLUSTRATIONS. a NEW YORK: D. APPLETON AND COMPANY, 549 & 551 BROADWAY. 1873. Al Dedicates TO THE MEMORY OF JOHN LAWSON, MRCYV.S., OF MANCHESTER, WHO FIRST URGED THE DESIRABILITY OF UNDERTAKING THIS TASK, AND WHOSE SINCERE AND INESTIMABLE FRIENDSHIP AND ENCOURAGEMENT FOR MANY YEARS o THE EDITOR AND TRANSLATOR HEREBY ACKNOWLEDGES WITH SORROWFUL a AFFECTION AND GRATITUDE. bene eer cine emad Sera, ‘ \BL6 Qoe Dh. Saw. PREFACE BY THE TRANSLATOR AND EDITOR. In undertaking the arduous task of translating and editing the ‘ Traité @ Anatomie Comparée des Animaux Domestiques’ of M. Chauveau, I have been moved by a desire to fill a void in medical literature which has always existed, so far as the English language is concerned. There has been no complete treatise on the anatomy of the domesticated animals, and the absence of such a work has exerted a serious influence on the progress of veterinary science, and doubtless proved more or less of a loss to the community at large. The only text book to which the student or practitioner of animal medicine could until recently refer, has been that on the anatomy of the Horse, written by the late distinguished army veterinary surgeon, William Percivall, more than forty years ago: a book which, though in every way creditable to its author, was notoriously incomplete, even as regards the anatomy of the only animal it treated of, and was without illustrations. No serious attempt has been made to teach the structure of the other useful creatures domesticated by man, valuable though many of them are; and the student who was anxious to acquire this knowledge had no guide to lead or instruct him. At college, this loss may not have been so severely felt as when, having graduated, he entered on the practice of his profession ; and if the experience of veterinary surgeons in general has been like my own, they will be ready to testify to the almost daily regret they felt at the very meagre notions of anatemy they possessed, and the benefit a complete and trustworthy manual would confer. My professional avocations in the army would not permit me to make the necessary dissections for the production of such a work: and indeed so many classical and standard treatises on the subject have appeared, during this century, on the Continent, and notably in France and Germany, that it would seem a mere waste of time and labour to attempt a task which viii PREFACE BY THE TRANSLATQR AND EDITOR. has been already so thoroughly accomplished by very zealous and pro- ficient anatomists. In selecting for translation the present treatise in preference to other works which are justly held in high estimation, I was influenced not only by the knowledge that it was written by one of the most talented com- parative anatomists and physiologists of the day, but by the ability and originality which are so conspicuous in every page. I was also aware that, for more than a century, the French veterinary schools have been celebrated for the careful and thorough manner in which anatomy has been taught by most efficient teachers, who are all selected by open com- petition; and that Professor Chauveau’s book was the approved dissection manual of these and other Continental schools. Excellent as was the first edition of the work, the second is still more complete; indeed it may be said to be almost a new book, owing to the assistance afforded by M. Arloing, an anatomist who promises to assume a high rank in his profession. The French treatise is illustrated by three hundred and sixty-eight wood- cuts, but for several reasons it was deemed advisable to select only one hundred and seventy-three from this number : those rejected being chiefly human figures, and either far larger than was necessary or compatible with the space at disposal, or not so well suited for such a work as 1 was intent on producing. Nearly sixty original figures have been added to those selected; and through the courtesy and liberality of Messrs. J. and A. Churchill, the total number has been increased to four hundred and fifty. The profuseness and general excellence of these drawings, and their great accuracy, will, it is hoped, materially lessen the fatigue and time demanded for the study of this most important subject, and prove valuable for reference to the operator or busy practitioner. No labour or pains have been spared to make the work the most complete and useful of any that has been produced. The best treatises in German, French, and Italian have been consulted in editing it, and when necessary, I have added to the descriptions. These additions are contained within brackets, thus ( ). As my task has been accomplished without any aid, I assume the entire responsibility for any errors of omission or commission that may exist; my aim bemg to. furnish what has been an urgent desideratum for very many years—a complete dissection manual for the student of veterinary science, a book of reference for the veterinary surgeon, and a work that might be available for the zoologist, comparative anatomist, ethnologist, and medical practitioner. I have for a long time believed that the two branches of medicine—human and animal—should be: more closely allied than they are at present, and that this alliance can only: be effected by a mutual study and recognition of the facts which prove that the two are really one—wide apart though they have hitherto been kept in this country—and that each is capable of conferring on the other great and lasting benefits. Hence my retaining what constitutes a new feature “~ PREFACE BY THE TRANSLATOR AND EDITOR. ix in the second edition of Chauveau’s treatise—the comparison of the organs of Man with those of ANIMALS. I have omitted from the translation the references made to the Dro- medary and Rabbit; these animals seldom, if ever, coming under the notice of the comparative pathologist in this country. My grateful acknowledgments are due to my friend and colleague, Professor Chauveau, for the great courtesy with which he not only sanc- tioned the translation now before the public, but offered to supply me with the proof sheets of the new edition as it passed through the press. To the numerous professional friends who pressed upon me the necessity of making such an extensive sacrifice of my few leisure hours, by under- taking a work of this magnitude, I have to express my deep regret at the delay which has occured in its appearance. The fault was not mine: but for the disturbance and abeyance of all business, save that of slaughter, in and around Paris while the book was in course of publication, my task must have been achieved nearly two years ago. I may assure them, however,. that the delay has been rather beneficial than otherwise; as it has allowed me to give more time to perfect what might, under other circumstances, have been less complete and satisfactory. GEORGE FLEMING. Brompron BARRACKS, CHATHAM. February, 1873. PREFACE TO THE FIRST EDITION. To present in a concise and complete form an exact description of the anatomical machinery of which the bodies of our domesticated animals are composed, has been our aim in writing the book now offered for public appreciation. We have sought for concision, not only in language, but also in the choice of facts and ideas, with a kind of stubbornness. In imposing on ourselves this condition, we believe we have rendered a service to those who may have recourse to the book, in economising their time. In an age of progress like the present, when the sciences are becoming multiplied and developed, and when the human mind, seized by the fever of production, gives forth every day books consecrated to the study of these sciences, there is scarcely leisure to read and to learn. It is, therefore, the duty of a writer to be brief. If he loads his book with puerile details; if he says that which may éasily be divined by his reader; and if he describes facts and ideas too redundantly; will he have attained the wished-for perfection —in a word, will he be complete? No, he will be tedious: a serious inconvenience, which neither elegance, warmth, nor brilliancy of style will always excuse when met with in a didactic work, and especially in an elementary treatise. No effort has been spared to achieve exactitude—the primary desideratum in such a work as this; neither have evenings spent in bibliographic re- searches, nor fatigue in the dissecting-room been considered. All published writings on animal organisation, general treatises, special manuals, mono- graphs, and articles in periodicals have been read and interrogated. But we have more particularly sought for information from Nature—that certain and infallible guide, always wise, even in her diversities ; we have consulted her, scalpel in hand, with a perseverance that nothing could repel. Animals of every kind were had recourse to, and we have largely profited by the immense resources which our position as principal of anatomical teaching in the Imperial Veterinary School has placed at our disposal. xii PREFACE TO THE FIRST EDITION. It was not enough that we should be correct, that we should faithfally describe the organs of the animal economy. It was desirable that the truth might be presented from a high philosophical point of view—one that should rise above details. It is necessary in a book, and especially in one on anatomy, that there should be a salient idea which might indicate its purpose and originality, and distinguish it as something more than a mere arid catalogue, by unifying the thousand different objects of which it treats. In support of this, we would ask permission to explain, in a few words, the idea that presided in the construction of our work. Among the beings or objects composing the natural world, animals are distinguished by diversity in size and external conformation. Is this diversity repeated in their internal structure? When order and simplicity prevail everywhere else in nature, should we expect to find disorder and complication there, or look for as many different organisations as there are particular species? To state these questions, and to resolve them in the affirmative, would be to insult the wisdom of the Creator. The early naturalists, guided by instinct rather than knowledge, admired a certain uniformity in the composition of animals. ; It was a good inspiration, which threatened to become effaced at the period when anatomical science, diffused and cultivated everywhere with the most laudable eagerness, daily discovered the secrets of the organisation of new species. Without a guide in the search for analogies, struck with the apparent differences their scalpel exposed every moment, the anatomists of that epoch neglected to compare the diverse animals. In presence of a new form of organs, they believed in the existence of a new instrument, and created a new name to designate it. Then was human anatomy, and that of the Horse, Ox, etc., established ; monographs became multiplied; as tbe different opinions increased, so there was the greater need for a bond to unite these incongruous materials; confusion commenced, and chaos was about to appear; and the principle of analogies was on the point of being buried beneath the ruins of science. Happily, two men appeared, men of genius, who were the glory of France—G. Cuvier and Etienne Geoffroy Saint-Hilaire ; two names which will be for ever illustrious, and which we love to unite as the expression of one and the same symbol. The first, after immense researches, ventured to compare the imnu- merable species in the animal kingdom with each other; he seized their general characters—the analogies which allied them to one another; he weighed these analogies, contrasted them with the dissimilarities, and established among them different kinds and different degrees; and in this way was he able to form natural groups, themselves subdivided into several categories in which individuals were gathered together according to their analogies and affinities. Then the chaos was swept away, light appeared, and the field of science was no longer obscured ; comparative anatomy was created in all its branches, and the structure of the animal kingdom was PREFACE TO THE FIRST EDITION. xiii brought within those laws of uniformity which shine throughout the other parts of creation. Geoffroy Saint-Hilaire followed Cuvier over the same ground. More exclusive than Cuvier, he entirely neglected the differential characters, and allowed himself to be governed by the consideration of resemblances. He especially pursued the discovery of a fixed rule for guidance in the search after these resemblances—a difficult task, and a dangerous reef, upon which the sagacity of his illustrious rival was stranded. To be more certain than Cuvier, and the better to grasp his subject, he restricted the scope of his observations, confining himself more particularly to the class of vertebrata in order to solve the enigma whose answer he sought. At last he found it, and made it known to us in those memorable, though abstruse pages, in which the meaning is often obscure and hidden, but which contain, nevertheless, magnificent hymns chanted to the honour of the Creator. The shape and functions of organs, he says, do not offer any stability, only their relations are invariable; these alone cannot give deceptive indications in the comparison of the vital instruments. He thus founded his great principle of connections, firmly established its value, fortified it by accessory principles, and held it up to the generations to come as a compass, a succourable beacon-light, under whose protection they might proceed to the conquest of analogies with confidence and security. Then was the philosophical sentiment decidedly introduced into the researches in organisation, and anatomy became a veritable science. Enthusiastically admiring these two great masters, we glory in be- longing to their school; it is, therefore, enough to say that the prevailing idea in our work has been inspired by their labours. Thus, in describing the organs in the somewhat numerous species of animals treated of, and noting their differential characters, we have always endeavoured to demonstrate their analogies. The hopes that Geoffroy Saint-Hilaire entertained for the future of philosophical anatomy have not been entirely realised. Naturalists, it is true, have always cultivated this admirable science ; Lecoq has preserved its traditions at the Lyons Veterinary School, in his simple, lucid, and elevated teaching; and at Toulouse, an able and learned professor, Lavocat, ~ has courageously hoisted his flag. But everywhere else, and particularly in the Medical Schools, has not anatomy remained essentially monographic and purely surgical? And many medical men and veterinary surgeons, only looking at the practical side of this science, and full of defiance with respect to speculative theories, will perhaps give us no credit for our efforts in bringing the anatomy of animals into philosophical courses. To these we have nothing to say; if they do not see how much science is developed and becomes comprehensible with. such elements; if they cannot under- stand all that is noble and useful in these generalising views; and if they do not feel elevated sentiments revolve in their mind in presence of the simplicity of Nature’s laws, it is because their thoughts are not in unison xiv PREFACE TO THE FIRST EDITION. with ours, and we carefully abstain from engaging in a sterile discussion with them. Such is our plan: have we executed it in a satisfactory manner ? We have not deluded ourselves with regard, to our strength, and willingly acknowledge that many resources and many qualities have failed us in carrying the enterprise to a favourable termination ; therefore we hope to be indulgently judged. If we have succeeded in facilitating the study of so important a subject as anatomy for the pupils of the veterinary schools ; if our book becomes, in the hands of practitioners, a useful surgical guide; if, lastly, medical men and naturalists find that it will assist them in their researches in com- parative anatomy, our object will have been attained, and we shall have received the best recompense which the honest writer can hope to obtain. Before terminating, a sentiment of justice and recognition again brings the honourable name of M. Lecog to our pen; the idea of this book was conceived at his lectures, and it is from these lectures that we have derived the major part of our materials; it was to satisfy the most imperious desire of our heart and conscience that we offered to dedicate this first attempt to him. Could it be better placed than under his patronage ? We have also willingly joined to his name that of M. H. Bouley, that eminent and devoted master, to whose advice we owe so much, and who has evinced the liveliest solicitude for us in circumstances which we can never forget. May he deign to accept this homage as the expression of our sincere recognition. We have found in the obligingness and intelligence of M. Rodet a very efficacious aid; he will permit us to tender all our gratitude. We have frequently put the complaisance of the students around us to a severe test; but they have never failed, and we are gratified in being able to thank them most cordially. We especially mention the name of M. Violet, whose intelligent zeal has spared us much toil in the difficult task imposed upon us. A. CHAUVEAU. Lyons, September 30, 1854, TABLE OF CONTENTS. a pees Translator and Editor’s Preface. . ‘ , Preface to the First Edition . : ‘ ‘i ‘ . ‘ Preface to the Second Edition : . z 3 E a Table of Contents , f : : F 5 : Table of Illustrations ‘ : - . ‘ i GENERAL CONSIDERATIONS. Definition and Division of Anatomy , ‘ Enumeration and Classification of the Domesticated Animals - General Idea of the Organisation of Animals, and the order followed i in studying their apparatus . BOOK I. LOCOMOTORY APPARATUS, First Section.—The Bones CuapPrer I.—The Bones in Generet Article 1.—The Skeleton . Article 1.—General Principles applicable. to the Study of all the Bones Name, Situation, Direction, and Configuration of the Bones Internal Conformation of the Bones. Structure of the Bones Development of the Bones Cuaprer II.—The Bones of Mammalia in Particular Article 1—Vertebral Column Characters Common to all the V esfabiee Characters Proper to the Vertcbree in each region 1. Cervical Vertebree 2. Dorsal Vertebree 3. Lumbar Vertebre 4. Sacrum 5. Coceygeal Vertebne Of the Spine in General Differential Characters in ise Vertebral Columa of ‘oglier than Soliped Animals : Comparison of the Vortabual Calum of Man with that of Antasie Article 1.—Tbe Head é ; : ' . The Bones of the Cranium J. Occipital a _ : . . . 2. Parietal . ‘ : . . % “ 8. Frontal : . é, & 6 2 xviii TABLE OF CONTENTS. 4. Ethmoid . 5. Sphenoid 6. Temporal The Bones of the Fae : 1. Superior Maxillary or Great Supermaxillary ; . Intermaxilla, Incisive Bone, Small Supermaxilla, or Premncilie . Palate Pterygoid . Zygomatic : . Lachrymal . Bones proper to the Nose, or Supernasal Turbinated Bones . Vomer 10. Inferior Maxillary ll. Hyoid. Of the Head in General Differential Characters in the Head. of other than Soliped Animals | Comparison of the Head of Man with that of Animals Article 11.—The Thorax . : : The Bones of the Thorax in Partibulay 1. Sternum of the Horse 2. Ribs . 5 Of the Thorax in General . Differential Characters in the Thorax of other than Soliped Animals 1. Sternum . 2. Ribs Comparison of the Thorax of Man with that of Animals 1. Sternum ; ‘ 4 ‘ F : . 2. Ribs ; F 2 ‘ Article 1v.— Anterior Limbs . 3 3" ° : Shoulder ‘ c 7 : Scapula i F 5 F : Arm. 2 = : ‘i - = . Humerus . : : - 5 ‘ F Fore-arm ‘ 5 3 r is 2 1. Radius 2. Ulna Anterior Foot , 1. Bones of the Carpus 2. Bones of the Metacarpus 3 3. Bones of the Digit, or Phalangeal Region OMAR owed + Differential Characters in the Anterior Limb of other than Soliped Ausnate Comparison of the Thoracic Limb of Man with that of the Domesticated Animals ‘ i Article v.—Posterior Limbs . ‘ is Pelvis 3 ; < . ¥ ‘ A. Coxee : F 4 e 5 3 . The Pelvis in Gensral : 5 . a Thigh . ‘ : . Femur : i‘ : . . Leg. : : . ‘ 1. Tibia . 2. Fibula 3. Patella TABLE OF CONTENTS. xix Posterior Foot . 1. Bones of the Tarsus 2. Bones of the Metatarsus 105 3. Bones of the Digital Region 105 Differential Characters in the Posterior Limb ‘of other then Soliped Animals 105 Comparison of the Abdomiual Liab of Man with that of the Plonidsticatad Animals ‘ . 107 Article v1—The Limbs in Genus amid their Payallstian : 109 Cuaprer III.—The Bones in Birds 5 . 112 Cuapter [V.—Theory of the Vertcbril Constitution of ihe Skeleton : 118 Seconp Srction.—The Articulations ‘ . é . 121 Cuarrer IL.—The Articulations in General A 3 i ‘ 121 General Characters of Diarthroses . z " . ‘ . 123 General Characters of Synarthroses . : 3 128 General Characters of Amphiarthroses or Symphyees : . 129 Cuaprer II.—The Articulations of Mammalia in Particular 3 129 Article 1.— Articulations of the Spine 2 . 180 Articulations between the Vertebre, or Inter eartebral Atealstions 3 130 Article u.—Articulations of the Head 2 : : . 135 1. Atlo-axoid Articulation . ‘ $ : 7 135 2. Occipito-atloid Articulation . p - 137 8. Articulations between the Bones of thie fed ‘ : 4 137 4. Temporo-maxillary Articulation ‘ 3 ‘ F 138 5. Hyoideal Articulations . . r . 2 . 139 Article 111.— Articulations of the Thorax ‘ 140 1, Costo-vertebral, or Articulations of the Ribs witehs the Valtebral etumina 140 2. Costo-sternal Articulations . . 141 8. Chondro-costal Articulations, or Avtiontations between the Ribs 4 142 4, Articulations between the Costal Cartilages . 5 3 142 5. Sternal Articulation peculiar to the Ox and Pig . : 142 6. The Articulations of the Thorax considered in a general manner, with respect to their Movements . , : : 142 Article 1v.—Articulations of the Anterior Linibs F 3 143 1. Scapulo-humeral Articulation. A : é 143 2. Humero-radial Articulation 6 . 144 8. Radio-ulnar Articulation : i 147 4, Articulations of the Carpus Z : ‘ 148 5. Intermetacarpal Articulations. ; : 152 6. Metacarpo-phalangeal Articulations 153 7. Articulation of the First Phalanx ithe the Seconil, or : Hest Tnier: phalangeal Articulation : 156 8. Articulation of the Second Philans with the Third, Second Tuter- phalangeal Articulation, or Articulation of the Foot ‘ 157 Article v-—Articulations of the Posterior Limbs : . 5 . 159 1. Articulations of the Pelvis . : : . : 159 2. Coxo-femoral Articulation . : . . . . I6l 3. Femoro-tibial Articulation i ‘ . 163 4, Tibio-fibular Articulation i ‘ . 7 167 5. Articulations of the Tarsus, or Hock : 3 ‘ 168 Cuarter III. —The Articulations in Birds . 7 7 ' 172 "PyTRD Srction.—The Muscles. ; 173 Cuarrer I.—General Considerations on the Striped ‘Muscles : : 174 The Striped Muscles in General : ‘ . . 174 XX TABLE OF CONTENTS. PAGE Structure of the Striped Muscles. ° ° « 178 Physico-chemical Properties of the Striped Muscles . 3 S 180 Physiological Properties of the i Muscles. . . . 181 Annexes of the Muscles : : ° a f 183 Manner of Studying the Muscles. : a 3 . 183 Cuarrer II.—The Muscles of Mammalia in Particular é 3 3 186 Article i—The Muscles of the Trunk . ‘i ‘ Z . 186 Subcutaneous Region . : ‘ é ‘ - ; 186 Fleshy Panniculus ‘ i j . - . . 186 Cervical Region . < ‘ 187 A, Superior Cervical or Spinal Region of the Neck . . . 187 1. Rhomboideus 5 ‘ : ‘ 4 ‘ 188 2. Angularis Muscle of the Scapula : : F . . 189 8. Splenius . : : . . : : 189 4. Great Complexes. i : : A . 191 5. Small Complexus (Trdislosnacteltensy : : 191 6. Transverse Spinous Muscle of the Neck (Spinalis Colli) : . 193 7. Intertransversal Muscle of the Neck ; ; 193 8. Great Oblique Musele of the Head (Obliquus Cavite Tiana) . 198 9. Small Oblique Muscle of the Head (Obliquus Capitis Superior) . 194 10. Great Posterior Straight Muscle of the Head . 195 11. Small Posterior Straight Muscle (Rectus Capitis Padtions Minor) 195 B. Inferior Cervical or Trachelian Region . . 195 1. Subcutaneous Muscle of the Neck ’Pannleutas Carnosus) . 196 2. Mastoido-humeralis (Levator Humeri). 5 . . . 196 3. Sterno-maxillaris . ; : é 2 3 ‘ 198 4. Sterno-hyoideus . : 7 3 : : . 198 5. Sterno-thyroideus. : : : 198 6. Omo-hyoideus, or Subscaqule-hyeldens 198 7. Great Anterior Straight Muscle of the Head (Rectus Capitis Anticus Major) ‘ 199 8. Small Anterior Straight Muscle of the Head eating Capitis Anticus Minor) é ‘ . 199 9. Small Lateral Straig). t Muscle (Obliquus Copiti Antivag) ; 199 10. Scalenus . : . 200 11. Long Muscle of the Neck Cones Coli) . 200 Differential Characters in the Muscles of the Cervical Reston of other tha Soliped Animals . : 3 F F ‘ 201 A. Superior Cervical Region 3 3 : 3 . 201 s. Inferior Cervical or Trachelian Heston . i ‘ : 201 Spinal Region of the Back and Loins. dé : » 203 1, Trapezius i i 3 5 203 2. Great Dorsal ‘atiedioons Dad . , 203 8. Small Anterior Serrated Muscle (Super ficialis Gostaruaiy : 205 4, Small Posterior Serrated Muscle (Superficialis Costarum) . . 205 5. Tlio-spinalis Muscle (Longissimus Dorsi) ‘ : 206 6. Common Intercostal Muscle (Transversalis Costarum) : 208 7. Transverse Spinous Muscle of the Back and Loins (Spinalis and Semispinalis Dorsi ! 209 Differential Characters in the Muscles of the Spinal Révion of the Back sual Loins of other than Soliped Animals . 909 Comparison of the Muscles of tle Back, Neck, and ere in Ria: with fii analogous Muscles in the Domesticated Animals . 209 A. Muscles of the Back ard Cervix . : ‘ F , ‘ 210 TABLE OF CONTENTS. xxi PAGE B. Muscles of the Neck . . : : i i: » 211 Sublumbar or In “erior Lumbar Region fi ‘ ‘ ; 211 1. Iliac Fascia or Lumbo-iliac Aponeurosis . F « 212 2. Great Psoas Muscle. 4 - - ‘ 212 3. Iliac Psoas Muscle (Iliacus) . : ‘ : : » 212 4. Small Psoas Muscle. F : ‘ 214 5. Square Muscle of the Loins (Gaevoctumibelis) j 214 6. Intertransverse Muscles of the Loins (Intertransversales Lamborum) 215 Differential Characters in the Muscles of the Sublumbar Region of other than Soliped Animals . . 215 Comparison of the Sublumbar Muscles of Man with those a Kiet : 215 Coccygeal Region. 3 , 2 . ‘ 3 . 215 1. Sacro-coccygeal Muscles Z : 215 2. Ischio-coccygeus (Compressor Caceyaaus) : : . 217 Region of the Head . i : F : : 217 A. Facial Region : at . : . . 217 1. Tabialis (Orbicularis Oris) 3 . . ‘ - 217 2. Alveolo-labialis (Buccinator) s 5 ; . 218 3. Zygomatico-labialis (Zygomaticus) . . : : 219 4, Lachrymo-labial, or Lachrymal Muscle . ‘ . 220 5. Sunornase labialis (Levator Labii Superioris) : 220 6. Supermaxillo-labialis (Nasalis Longus Labii Supevidris) : . 220 7. Great Supermaxillo Nasalis (Dilatator Naris Lateralis) P 221 8. Small Supermaxillo-nasalis (Nasalis Brevis Labii pee . 221 9. Transversalis Nasi (Dilatator Naris Anterior). 221 10. Middle Anterior Muscle (Depressor Labii Superiori) . 222 11. Maxillo-labialis (Depressor Labii Inferioris) . : ‘ 222 12. Mento-labialis, or Muscle of the Chin ‘ é ; . 222 13. Middle Posterior Muscle (Levator Menti) , ‘ 222 B. Masseterine or Temporo-maxillary Region . F 223 1. Masseter : : : . ; 223 2. Temporal or Crotaphitic Muscle ‘ : é . 223 8. Internal Pterygoid (Pterygoideus Intern) ‘ . ‘ 224 4, External Pterygoid ‘ ; : ‘i . 224 5. Digastricus . ‘ ‘ > , F 225 co. Hyoideal Region . ‘ - . : F » 225 1. Mylo-hyoideus ¥ z z : j : 225 2. Genio-hyoideus . J : 5 + 226 3. Stylo-hyoideus tit eutdeus, Magnus) F F : 227 4, Kerato-hyoideus (Hyoideus sila 3 . 3 . 227 5. Occipito-styloideus . : . ‘ - 227 6. Tranversalis Hyoidei : 228 Differential Characters in the Muscles of the Head of other than Soliped Animals é r 3 ; : . : . 228 A. Facial Region . : : 228 B. Masseterine or Manapote aanctlibaey Baeion a : . 229 9. Hyoid Region é 230 Cormpantion. of the Muscles of the Human Head with those of the Domes ticated Animals 230 A. Epicranial Muscles : : : : | B. Muscles of the Face F : . . ca c. Muscles of the Lower Jaw 5 : . : » 231 p. Hyoid Muscles. ‘ ‘ : . ‘ : 231 Axillary Region . . ° : . ° . . 231 TABLE OF CONTENTS. PAGE 1. Superficial Pectoral (Pectoralis Transversus) . : F 23% 2. Deep Pectoral ; 233 Diflerential Characters in the Muscles of the Axillary Region of thee than Soliped Animals ‘ : ‘ ; . Z 235 Costal Region ; : : é . : 235 1. Great Serratus 5 ‘ é . 236 2. Transverse Muscle of the Ribs (Lateral Sterni) . 236 3. External Intercostals ; ‘ ‘4 é . 287 4, Internal Intercostals a ‘5 . 7 . 237 5. Supercostals (Levatores Costarum) . . : . 237 6. Triangularis of the Sternum (Sterno- epctales) ‘ 237 Differential Characters in the Muscles of the Costal Region of other than Soliped Animals . ‘ 238 Comparison of the Thoracic Muscles of Man wiih those ‘of the Damncsticnted Animals : ‘ F . ‘ 238 Inferior Abdominal Rasta 5 ‘ F é : . 238 1. Abdominal Tunic : 3 r ‘ ‘ F 239 2, White Line. : ‘i 240 3. Great or External Oblique of the Abdomda F : ‘ 240 4. Small or Internal Oblique of the Abdomen . F ‘ 242 5. Great Rectus Muscle of the Abdomen . : ‘ : 243 6. Transverse Muscle of the Abdomen . 244 Differential Characters in the Muscles of the Abdominal Region of other than Soliped Animals 2 ‘ 245 Comparison of the Abdominal Muscles of Man with those of Animals . 245 Diaphragmatic Region . é : : . 246 Diaphragm : 3 = ‘ 4 : ; 246 Differential Characters in the Diaphragm of other than Soliped Animals 248 Comparison of the Diaphragm of Man with that of Animals. ‘ 248 Article 1.—Muscles of the Anterior Limbs. 5 : . 248 Muscles of the Shoulder ‘ . - : ‘ : 249 A. External Scapular Region. : ‘ < . 249 1. External Scapular Aponeurosis . 249 2. Long Abductor of the Arm, or Scapular portion af the Deltoid (Teres Major) . : é . 249 3. Short Abductor of the on or Toins nor F és ‘ 250 4, Superspinatus (Antea Spinatus) . z : , . 251 5. Subspinatus (Postea Spinatus) . 4 : - is 251 B. Internal Scapular Region . 7 , : 252 1. Subseapularis . : ‘ é : 252 2. Adductor of the Arm, or - Teres Major ‘ 5 . 253 3. Coraco-humeralis, Cai aco-brachialis, or Omo-brachialis A ‘ 254 4, Small Scapulo-humeralis 254 Differential Characters in the Muscles of ihe Shoulder of other then Soliped Animals. 254 Comparison of the Muscles of the Shoulder of Man with those of Animals . 255 Muscles of the Arm. ° ‘ ‘i : 255 A. Anterior Brachial Région. _ . 255 1. Long Flexor of the Fore-arm, or Brachial Biceps (Flexor Brachii) 255 2. Short Flexor of the Fore-arm (Humeralis Externus) . ; 256 B. Posterior Brachial Region . : . 258 1. Long Extensor of the Fore-arm (Caput Magnum) 3 : 258 2. Large Extensor of the Fore-arm (Caput Magnum) . : 258 3. Short Extensor of the Fore arm (Caput Medium) 4 ‘ 259 TABLE OF CONTENTS. 4. Middle Extensor of the Fore-arm (Caput Parvum) 5. Small Extensor of the Fore-arm, or Anconeus : Differential Characters in the Muscles of the Arm of other then Soliped Animals ‘ Comparison of the Muscles of the Arm of Man with those of Antinaly Muscles of the Fore-arm Antibrachial Aponeurosis a, Anterior Antibrachial Region. 1. Anterior Extensor of the Metacarpus (Extensor Metncarpi tiene) 2. Oblique Extensor of the Metacarpus (Extensor Metacarpi Obli oe 3. Anterior Extensor of the Phalanges (Extensor Pedis. 4. Lateral Extensor of the Phalanges aaa Suffraginis) s. Posterior Antibrachial Region 1. External Flexor of the Metacarpus, « or Posterior Winaries , 2. Oblique Flexor of the Metacarpus, or Anterior Ulnaris (Flexor Metacarpi Medius) * 3. Internal Flexor of the Metacarpus, or Palmeria Magnus (Flexor Metacarpi Internus) 4. Superficial Flexor, Sublimis of the Phalanges, or Perforatus 5. Deep Flexor of the Phalanges, or Perforans Differential Characters in the Muscles of the Fore-arm of other thats Soliped Animals . . . Muscles proper to the Fore-arm i in : Carnivora . . . 1. Proper Extensor of the Thumb and Index . ; 7 2. Long Supinator. 7 3 . . r 8. Short Supinator .. . ‘ ‘ . 4. Round Pronator : : : ‘ : % 5. Square Pronator Comparison of the Muscles of the Fore- -arm. of Man with itiane of Animal a, Anterior Region % ‘ 3 Fi : a B. External Region : . : ‘ c. Posterior Region i . i ‘ Muscles of the Anterior Foot or Head . : A A. Muscles of the Anterior Foot in Canitvery ‘ : i . Short Abductor of the Thumb . . . 7 . . Opponens of the Thumb. : ° , , . Short Flexor of the Thumb - . . . . . Adductor of the Index ‘ . . . . . Cutaneous Palmar : Palmaris Brevis) . . . ° . Adductor of the Small Digit ‘ 2 . . . Short Flexor of the Small Digit és 3 A . . Opponens of the Small Digit ‘ : . . . Lumbrici ‘ 3 7 . . Metacarpal Tikensesoais: uses 3 ‘ ‘ : B, Muscles of the Anterior Foot in the Pig . . é c. Muscles of the Anterior Foot in Solipeds ‘ é ‘ p. Muscles of the Anterior Foot in Ruminants “ . Comparison of the Hand of Man with that of Animals , A. Muscles of the Thenar Eminence . 3 : . B. Muscles of the Hypothenar Eminence. : . . c. Interosseous Muscles ‘ . s é Article 11.—Museles of the Posterior Limbs i - Muscles of the Gluteal Region, or Croup , . 1, Superficial Gluteus (Gluteus Externus) —. . SOMNAAEWDE, ry xviii PAGE 259 260 260 260 261 461 262 262 263 263 264 265 265 266 266 267 268 270 272 272 272 274 274 274 274 274 276 276 276 276 276 277 277 277 277 277 277 277 278 78 278 278 279 279 279 279 279 280 280 280 xxiv TABLE OF CONTENTS. 2. Middle Gluteus (Gluteus Maximus) 3. Deep Gluteus (Gluteus Internus) Differential Characters in the Muscles of the Gluteal Region of ather ita Soliped Animals . , Comparison of the Gluteal Muscles of Man sel those of Animals ‘ Muscles of the Thigh , a. Anterior Crural, or Femoral Region . : : 1. Muscle of the Fascia Lata (Tensor Vagine). 2. Crural Triceps 6 : 8. Anterior Gracilis (Crureus vel Croralis). B. Posterior Crural Region F 1. Long Vastus (Biceps Abductor Femor is) 2. Semitendinosus Muscle (Adductor Tibialis) 3. Semimembranosus (Adductor Tibialis) . c. Internal Crural Region ‘ . Long Adductor of the Leg (Sartorius) . Short Adductor of the Leg (Gracilis) . Pectineus . Small Adductor of the Thigh (Adductor Femoris) . . Great Adductor of the Thigh (Adductor ssiceks . Square Crural (Quadratus Femoris). . External Obturator . Internal Obturator . . Gemelli of the Pelvis eGeiniut) Differential Characters in the Muscles of the Thigh af other shai Soliped Animals : 2 : : 4. Anterior Crural Region B. Posterior Crural Region c. Internal Crural Region . Comparison of the Muscles of Man’s Thigh swith those of the Thigh of Animals : 2 - é . A. Anterior Muscles . : s. Muscles of the Posterior Region c. Muscles of the Internal Region 7 Muscles of the Leg : . é . Tibial Aponeurosis A. Anterior Tibial Region ‘ 1. Anterior Extensor of the Phalanges (Extensor Pedis) - 2 Lateral Extensor of the Phalanges eo 3. Flexor of the Metat:rsus F B. Posterior Tibial Region . Gastrocnemii, or Gemelli of the Tibia (Gastrvonemins Batons) . Soleus, or Solearis (Plantaris) . Superficial Flexor of the Pha'anges, or Perforatus (Gastroonemius Internus) . 4. Popliteus ; 5. Deep Flexor of the Phalanges, or Porthnans ( Flexor Pedi) 6. Oblique Flexor of the Phalanges (Flexor Pedis Accegssorius) . Differential Characters in the Muscles of the Leg of other than dia DHIARrpHDe, wrne Animals A. Anterior Tibial Region B. Posterior Tibial Region Comparison of the Muscles of the Leg of Man with those of Animals A. Anterior Region PAGE 281 282 283 283 283 283 284 284 285 286 286 287 288 288 288 289 289 291 291 292 292 292 293 294 294 294 295 295 295 295 296 297 297 298 298 298 300 302 302 304 304 304 305 306 306 306 309 309 309 TABLE OF CONTENTS. gs, External Region . c. Posterior Region Muscles of the Posterior Foot Comparison of the Muscles of the Foot of Man with those of Animals A. Dorsal Region s. Plantar Region c. Interosseous Muscles Cuarter ITI—The Muscles in Birds . Cuartrr IV.—General Table of the insertions of the Museles 3 in | Solipeds BOOK II. THE DIGESTIVE APPARATUS, Cuapter I.—General Considerations on the Digestive Apparatus Cuarter Il.—The Digestive Apparatus in Mammalia Article 1.—Preparatory eee ot the ae See The Mouth Lips. . Cheeks . Palate . . Tongue . Soft Palate . Teeth . The Mouth in General . Differential Characters in the Mouth of other than Soliped Animals Comparison of the Mouth of Man with that of Animals The Salivary Glands i 1, Parotid Gland . 2. Maxillary, or Submaxillary Gland . 3. Sublingual Gland 4. Molar Glands ‘ 5. Labial, Lingual, and Palatine Glonds 3 Differential Characters in the Salivary Glands of other thaw Soliped Animals ‘ Comparison of the Salivary ‘Glands of Man att thoes of Animals The Pharynx Differential Characters in the Diaries of other ‘tien Soliped Misia 3 Comparison of the Pharynx of Man with that of Animals The @sophagus Differential Characters in the (Raowhawne of other ‘ia Seine Autiaals Comparison of the esophagus uf Man with that of Animals : Article 1.—The Essential Organs of Digestion The Abdominal Cavity . Differential Characters in the Abdominal Cavity of “other than 8. JHipeil Animals ‘ Comparison of the Abddininel Cavity of Man with that of Aeimels: The Stomach. . ts : ‘ 1. The Stomach of Solipeds F ‘ Differential Characters in the Stomach of other than Soliped Animals 1. The Stomach of the Pig 2. The Stomach of Carnivora . 3. The Stomach of Ruminants Comparison of the Stomach of Man with that of Attias Ce oe ee XXV PAGE 309 309 311 311 311 312 313 313 315 325 330 330 330 330 332 332 334 340 344 355 356 362 364 365 367 369 369 370 370 372 372 376 377 377 380 380 380 380 384 385 385 385 393 893 393 393 400 xxvi TABLE OF CONTENTS. PAGE The Intestines 7 : : . ° 5 A 400 1. The Small Intestine : . . . . . 400 2. The Large Intestine. % : 7 < : 407 a. Coecum é ‘ F . 407 B. Colon. F : : : . . 410 c. Rectum . 413 Differential Charstens i in the fraestines of other than Soliped Aniiale : 414 1. The Intestines of Ruminants : 7 F 3 . 414 2. The Intestines of the Pig : : , j e 416 3. The Intestines of Carnivora F . . 416 Comparison of the Intestines of Man with those of Animals 417 General and Comparative Survey of the Abdominal or Essential Portion of the Digestive Canal. . 418 Organs Annexed to the Ahduainel Putian of hie Hiessuve Cunal ‘ 419 1. Liver j : ‘ és : ‘ . 419 2. Pancreas . ‘ . : ‘ ‘ 427 3. Spleen z 428 Differential Characters in ite Or; an ‘Aanescedl to the Abalone Portion of the Digestive Canal in other than Soliped Animals 4382 Comparison of the Organs Annexed to the Abdominal Portion of the Digestive Canal of Man with those of Animals . ‘ 4 . 434 Cuapter III.-—The Digestive Apparatus of Birds . . : é 435 BOOK III. RESPIRATORY APPARATUS, Cuapter I.—Respiratory Apparatus in Mammalia . és . . 439 The Nasal Cavities . ‘ . : . ‘ 439 1. The Nostrils , . . . : . 440 2. The Nasal Fossee : . . . . F 441 3. The Sipuses 446 Differential Characters in the Nasal Cavities of other than Boliped Animals 448 Comparison of the Nasal Cavities of Man with those of Animals ‘5 449 The Air-tube succeeding the Nasal Cavities 2 ‘ « » 449 1. The Larynx . ‘ . . & , 449 2. The Trachea . ‘A A * ° . 457 3. The Bronchi ; 460 Differential Characters in the Aietube suecsading the Nasal Fosse of other than Soliped Animals 461 Comparison of the Larynx aud Trachea of Man with these Organs in the Domesticated Animals . . ‘ 462 The Thorax . . 462 Differential Characters in es Merage of other fin Soliped Nrimoods 466 The Lungs ‘ . 466 Differential Characters in he ere of other than Soliped Atal : 470 Comparison of the Larynx, Trachea, and Lungs of Man with the same Organs in Animals . 471 E Glandiform Bodies connected with the Respiratory Apparat ‘ 472 . The Thyroid Body . : . 472 2 The Thymus Gland ‘ 473 Differential Characters in the Glandiform Bodies annexed to the Respiratory Apparatus of other than Soliped Animals ‘ . 474 TABLE OF CONTENTS. xxvii Comparison of the Glandiform Bodies annexed to the Respiratory Apparatus ie in Man with those of Animals ‘ 7 . . . 475 Cuarter II.—The Respiratory Apparatus of Birds 5 : . - 475 BOOK IV. URINARY APPARATUS. 1. The Kidneys . . Z é ‘ ‘ 7 484 2. The Ureters : e ‘ ‘ : . 490 3. The Bladder . c : ‘ ‘ , z 491 4. The Urethra. é : : z 2 . 493 5. The Suprarenal Capsules : 494 Differential Characters of the Tikinary Apparatas in “thes thou Soliped Animals ‘ 495 Comparison of the Urinary Avgparitus of Man with that of Avinials . 496 BOOK V. CIRCULATORY APPARATUS. First Section.—The Heart : : , F : « 499 1. The Heart as a Whole F : 5 . F 499 2. External Conformation of the Hae ‘ : ‘ 3 - 500 3. Internal Conformation of the Hvart . é : s s 503 4. Structure of the Heart . 4 7 - . . - 507 5. The Pericardium . : ‘ “i : Fs - 512 6. The Action of the Heart. . 513 Differential Characters in the Ebant of sthee than Solipad Animals 5 513 Comparison of the Heart of Man with that of Animals sl ‘ . 514 Seconp Section.—The Arteries ; ; ‘ ! - : 515 Cuapter I.—General Considerations . : - . A . 515 Cuaprer II.—Pulmonary Artery . ‘ . 3 ° . 521 Cuarrer III.—Aorta . 2 ei . . 522 Article 1—Common Aorta, or “Aortie Trunk . . _ ‘ 522 Cardiac, or Coronary Arteries . A . 3 . - 523 Article 1.—Posterior Aorta é : . ‘ A 523 Parietal Branches of the Posterior Aorta . 3 3 ‘ . 525 1, Intercostal Arteries ‘ 7 . 7 < é 525 2.. Lumbar Arteries. : - ‘ ; . . 526 3. Diaphragmatic Arteries : 5 . , ‘ 526 4. Middle Sacral Artery : : 5 ‘ . 526 Visceral Branches of the Posterior Aorta “ ‘ : ‘4 526 1. Broncho-Césophageal Trunk E : . 526 2. Coeliac Artery . ‘ ‘ ; . ‘ 527 3. Great Mesenteric Artery £ 7 : : . §29 4, Small Mesenteric Artery . ¥ ‘ ‘ é 532 5. Renal, or Emulgent Arteries ” J A . 584 6. Spermatic Arteries . ‘ 534 7. Small Testicular Arteries (Male), Uterine Aviadien (Female) . 535 Differential Characters in the Posterior Aorta and its Collateral Branches of other than Soliped Animals é ; F , he 585 1. Posterior Aorta in Ruminants 3 2 : . 535 2. Posterior Aorta in the Pig ; “ “ ; 537 38. Posterior Aorta in Carnivora 3 ‘: . 537 Comparison of the Aorta of Man with that of Animals : - - 538 xXvili TABLE OF CONTENTS. Article nt.—Internal Iliac Arteries, or Pelvic Trunks F ; . Umbilical Artery . . Internal Pudie, or Bulbous Avery . Subsacral, or Lateral Sacral Artery . Iliaco-muscular, or Ilio-lumbar Artery . Gluteal Artery . Obturator Artery . Iliaco-femoral Artery ‘ Differential Characters in the Internal Iliac Aarteries of other than Soliped Animals : 5 : 1. Internal Tiac Meieries of Tintaadts 2. Internal Iliac Arteries of the Pig 8. Internal Iliac Arteries of the Carnivora . Comparison of the Internal Iliac Arteries of Man with those of sernal Article 1v.—Exterual Iliac Arteries, or Crural Trunks Femoral Artery . 1. Prepubic Artery . 2. Deep Femoral, Deep Muscular, or iGirent Postoniey Muscular Artery of the Thigh i ‘ 3. Superficial Muscular, or Great Anterior Muscular Avery 4. Innominate Muscular, or Small Muscular Arteries . 5. Saphena Artery : 3 ‘ . ‘ . Popliteal Artery . ‘ 3 : . Terminal Branches of the Popliteal Artery 1. Posterior Tibial Artery 2. Anterior Tibial Artery 3. Pedal Artery Differential Characters in the External ine Ar re of other than Solined Animals fs 1, External Tiac Arteries of Ruminants 2, External Iliac Arteries of the Pig 3. External Iliac Arteries of Carnivora Comparison of the External Iliac Arteries of Man with ifiose of Andmdle Article v.—Anterior Aorta Article v1.—Axillary Arteries, or Bradhial Praake Collateral Branches of the Axillary Arteries . 1. Dorsal, Dorso-muscular, or Transverse Cervical Agary . Superior Cervical, Cervico-muscular, or Deep Cervical Artery . Vertebral Artery . Internal Thoracic, or ‘teen Mammary Aetery A . External Tvarntic, External Mammary, or Inferior Thoracic Revere . Inferior Cervical Artery . Superscapular Artery . Subseapular Artery ; : 2 ; Terminal Branch of the Brachial Tran, or Humeral Artery 1. Anterior Radial Artery ; 2. Posterior Radial Artery 1. First Terminal Branch of the Posterior Radial Artery, or Common Trunk of the Interosseous Metacarpals 2. Second Terminal Branch of the Posterior Radial Avhony: or Colla- teral Artery of the Canon 3 é Differential Characters in the Axillary Arteries of Non- sotiped Animals 1, Axillary Arteries of Ruminants 2. Axillary Arteries of the Pig PUMA wWde DN Op wD PAGE 538 538 540 540 541 542 542 543 543 543 544 544 545 545 547 547 548 548 549 549 549 550 550 551 551 Ny 555 555 556 556 557 559 559 560 560 561 561 563 563 564 564 564 565 566 567 568 569 570 570 572 TABLE OF CONTENTS. 3. Axillary Arteries of Carnivora . : . Comparison of the Axillary Arteries of Man with those of Animals Article vir—Common Carotid Arteries Occipital Artery é Internal Carotid Artery External Carotid Artery . 1, External Maxillary, Facial, or Glosso-Facial Axtery 2. Maxillo-Muscular Artery . : 3. Posterior Auricular Artery : 4, Superficial Temporal Artery, or Temporal Trunk 5. Internal Maxillary, or Gutturo-maxillary Artery Differential Characters in the Carotid Arteries of Non-soliped Acitinals 1, Carotid Arteries of Carnivora 2. Carotid Arteries of the Pig . 8. Carotid Arteries of Bunions ; Comparison of the Carotid Arteries of Man with those of Katronis : Tuirp Section.—The Veins Cuarter I.—General Considerations Cuapter II.—Veins of the Lesser Circulation, or 7 Palmonasy Veins Cuapter III.—Veins of tle General Circulation Article 1.—Cardiac, or Coronary Veins Article 1.—Anterior Vena Cava Jugular Veins - Roots of the Jugular Z : 1. Superficial Temporal Vein 2. Internal Maxillary Vein F é . 3. The Sinuses of the Dura Mater . : : 5 Axillary Veins . : : F F F : 1. Subscapular Vein : é 7 . 2. Humeral Vein . F E . 3. Spur, or Subcutaneous Thoracic Veia a zi . 4, Deep Veins of the Fore-arm ; ‘ ‘ - 5. Superficial Veins of the Fore-arm - . 6. Metacarpal Veins . F ‘ ‘ : ‘ 7. Digital Veins . 7 és . 8. Veins of the Foot, or Uoxval Revton : 5 . a, External Venous Apparatus . : < . b. Internal, or Intra-osseous Venous Apparatus . F Article m1.—Posterior Vena Cava ‘ ‘ e ° Diaphragmatic Veins. ‘ 7 . : Vena Porte . : : ‘ 1. Roots of the Vena Portes 2 : . 2. Lateral Affluents of the Vena Porte Renal Veins % Spermatic Veins Lumbar Veins Common Iliac Veins, or Pelvi gpl mane . Internal Iliac Vein . F ; p ‘ F . External Iliac Vein r 3 P, . Femoral Vein . Popliteal Vein . : ° . Deep Veins of the Leg ‘ ‘ . : . Superficial Veins of the Leg. $ ; . Metatarsal Veins. 3 ‘ * : . Veins of the Digital Region. é . . xxix PAGE 572 574 575 577 579 581 581 585 585 585 586 590 590 591 592 595 596 596 599 599 599 600 601 603 603 605 605 609 610 610 610 610 611 611 612 612 612 616 617 617 617 620 621 621 621 622 622 622 623 623 623 623 624 624 625 XXX TABLE OF CONTENTS. Differential Characters in the Veins of other than Soliped Animals . Comparison of the Veins of Man with those of Animals Fourrs Srcrion.—The Lymphatics Cuarrnr I.—General Considerations ' Lymphatic Vessels . : . 5 ‘ 7 Lymphatic Glands, or Ganglia i : 7 ‘ Cuarter I].—The Lymphatics in Particular. ‘i 3 ‘ Article 1.—The Thoracic Duct . Article u—The Lymphaties which constitute the Affiuents of sig Thewaie Duct . Lymphatics of the Abdominal Limb, Pelvis, Abdominal Parietes, and Pelvi-inguinal Organs : . . 1. Sublumbar Glands . 2. Deep Inguinal Glands 8. Superficial Inguinal Glands 4. Popliteal Glands é 5. Iliac Glands ‘ : 6. Precrural Glands ‘ 3 Lymphatics of the Abdominal Viera j 1. Glands and Lymphatic Vessels of the Reston and Floating Colon 2. Glands and Lymphatic Vessels of the Large Colon ‘ 3. Glands and Lymphatic Vessels of the Caecum : : 4. Glands and Lymphatic Vessels of the Small Intestine 5. Glands and Lymphatic Vessels of the Stomach 6. Glands and Lymphatic Vessels of the Spleen and Liver . Glands and Lymphatic Vessels of the Organs contained in the Thoracic Cavity a : Glands and Lymphatic Vessels of the Thoverte Parietes Lymphatic Vessels of the Head, Neck, and Anterior Limb 1. Prepectoral Glands ‘ 2. Pharyngeal Glands . 8. Submaxillary, or Subglossal ‘Cande 4. Prescapular Glands : 5. Brachial Glands Article 11.—Great Lymphatic Vein Differential Characters in the Lymphatics of Ni omseliped Animes Cuaprer III.—The Circulatory a a in Birds Article 1.—The Heart 4 : Pe Article 1.—The Arteries - . - - ‘ ‘ " Article 11.—The Veins i ‘i : ‘ : Article 1v.—The Lymphat'es ; e “ F BOOK VI. APPARATUS OF INNERVATION. First SEcTION.—The Nervous System in General General Conformation of the Nervous System Structure of the Nervous System Properties and Functions of the Nervous Systems Srconp Srcrion.—The Central Axis of the Nervous System CaaptTer I.—Protective and Enveloping Parts of the Cerebro- acta Axis The Bony Case which lodges the Central eee Axis 1. The Spinal Canal. ‘ , 2. The Cranial Cavity ° ae ‘ : . : PAGE 625 626 627 627 627 632 634 634 637 638 638 638 638 640 640 640 640 640 641 641 641 641 642 642 642 643 643 643 644 644 644 644 645 647 647 648 649 649 650 651 652 655 659 659 659 659 660 TABLE OF CONTENTS. The Envelopes of the Cerebro-spinal Axis 1. The Dura Mater 2, The Arachnoid 3. The Pia Mater . Differential Characters in the Protecting ant Brvdloptue Parts at the Cerebro-spinal Axis in other than Soliped Animals Comparison of the Protective and Enveloping Parts cf the Contiro- spiel Axis of Man with those of Animals Cuaprer IJ.—The Spinal Cord . External Conformation of the Spinal Cord ‘ Internal Conformation and Structure of the Spinal Cord . Differential Characters in the Spinal Cord of the Domesticated pauls other than Solipeds Comparison of the Spinal Cord of Man with that of Animals Cuarter III.—The Encephalon : z z Article 1—The Encephalon as a Whole Article 1.—The Isthmus . 7 External Conformation of the Isthmus : 1. The Medulla Oblongata a 2. The Pons Varolii . . The Crura Cerebri . The Crura Cerebelli The Valve of Vieussens . . The Corpora Quadrigemina, or Bigemina . The Optic Thalami . The Pineal Gland . . The Pituitary Gland Internal Conformation of the Isthmus 1. The Middle Ventricle, or Ventricle of the optic Thalami 2. The Aqueduct of Sylvius 3. The Posterior, or Cerebellar ‘Veutuidle Structure of the Isthmus . Differential Characters in the fates of orher fia Solyped aml . Comparison of the isthmus of Man with that of Animals Article 11.—The Cerebellum : . 1. External Conformation of the Cersballuns 2, Internal Conformation of the Cerebellum Differential Characters of the Cerebellum in other than Galiued, seth Comparison of the Cerebellum of Man with that of Animals Article 1v.—The Cerebrum : External Conformation of the Cerebrum 1. The Longitudinal Fissure 2. The Cerebral Hemispheres Internal Conformation of the Brain 1. The Corpus Callosum . The Lateral, or Cerebral Ventricles . The Septum Lucidum . . The Cerebral Trigonum (or Forni) . The Hippocampi . The Corpora Striata . The Cerebral Choroid Plexus, and Yelum Interpositum : Structure of the Cerebrum Differential Characters in the Braitt of thier than Soliped Animals Comparison of the Brain of Man with that of Animals : OHDIHMAUPW NYOSHONP WD EXxi PAGE 660 663 666 666 672 672 672 675 679 693 694 695 696 698 xxxii TABLE OF CONTENTS. TuirD Section.—The Nerves Cuaprer I.—The Cranial, or Sneephallis Nerves . First Pair, or Olfactory Nerves 2. Second Pair, or Optic Nerves . ‘ 3. Third Pair, or Common Motor Ocular Nerves 4. Fourth Pair, or Pathetici Nerves 5. Fifth Pair or Trigeminal Nerves . 6, Sixth Pair, or External Motor Ocular Nerves 7%, 8. — . Seventh Pair, or Facial Nerves Eighth Pair, or Auditory, or Acoustic Werves A 9. Ninth Pair, or Glosso-Pharyngeal Nerves . 10. Tenth Pair, Vagus, or Pneumogastric Nerves 11. Eleventh Pair, Spinal, or Accessory Nerves of the Preumogastries 12. Twelfth Pair, or Great Hypoglossal Nerves Differential Characters in the Cranial Nerves of other than Boliped Animals Comparison of the Cranial Nerves of Man with those of Animals Cuapter II.—Spinal Nerves : Article 1—Cervical Nerves (Eight Pairs) Article 1.—Dorsal Nerves (Seventeen Pairs) Article m1.—Lumbar Nerves (Six Puirs) Article 1v.—Sacral Nerves (Five Pairs) Article v.—Coccygeal Nerves (Six to Seven Bites) Article v1.—Composite Nerves formed by the Inferior Ramuscules of the Spinal Branches Diaphragmatic Nerves ‘ . : 3 Brachial Plexus A : . ‘ . ‘ . Diaphragmatic Br: tisha . Branch to the Angularis and Bhombaidens . Branch to the Serratus Magnus, or Superior Thoracic . Branches to the Pectoral Muscles, or Inferior Thoracic . . Subcutaneous Thoracic Branch . Branch to the Great Dorsal . Axillary, or Circumflex Nerve . Nerve of Adductor of tiie Arm, or Teres Major 2 . Subseapular Branches . Superscapular Nerve 11. Anterior Brachial Nerve 12. Radial Nerve 13. Ulnar, or Cubito- cutscene Nerve 14. Median, or Cubito-plantar Nerve Differential Characters in the Brachial Plexus of wthar ‘tiie Soliped Animals : Comparison of the Bragiital Plexus et Man wath that of Actiamais Sacro-lumbar Plexus 1. Iliaco-muscular Nerves . i: 2. Crural, or Anterior Femoral Nerve . 3, Obturator Nerve 4. Small Sciatic, or Anterior and Postenior Gluteal ‘Neves, 5. Great aetatin: or Great Femoro-popliteal Nerve . Collateral Branches Terminal Branclies Differential Characters in the Sacto-lumbar Plexus af other than Soliiped Animals Comparison of the Sacro-lumbar Plexus of Man with that of Animals a SODMNMS MWh H 752 753 793 760 763 T717 777 778 TABLE OF CONTENTS, xxxili Cuarter III.—The Great Sympathetic . : i : 1. Cephalic Portion of the Sympathetic Gain A . . . 782 2. Cervical Portion of the Sympathetic Chain ‘ ‘ ‘ - 783 3. Dorsal Portion of the Sympathetic Chain. : ‘ 786 4, Lumbar Portion of the Sympathetic Chain - : . 788 5. Sacral Portion of the Sympathetic Chain. 7388 Differential Characters in the Great Sympathetic of other than Solipea Animals ‘ . 789 Comparison of the Gr eat Sympathetic of Man with that of Ania 789 Cuapter IV.—The Nervous System of Birds. ‘ : - . 790 BOOK VII. APPARATUS OF SENSE. Cuarter I.—Apparatus of Touch . F ‘ < 792 Article 1—Of the Skin Proper Fi < + , 782 Article 1.—The eo y aed a ‘ < 7 797 The Hair % P i . 797 Horny ‘Prodtaiions 7 , ‘ . 3 799 1, The Hoof of Solipeds 2 P . 3 - 800 a. The Parts contained in the Hoot ‘ ‘ ° ‘ 800 b. Description of the Hoof . 5 a ‘ . $805 2; The Claws of Ruminants and Bachedexus ' - r 812 3. The Claws of Carnivora z 3 : ” . 812 4, The Frontal Horns ‘ 3 B . ‘i 813 5. The Chesnuts : - : ‘ . . 813 (6. The Ergots 5 . é s : 813) Cuarrer II.—Apparatus of Taste : $13 Differential Characters in the bic nai of Taste of other then Soliped Animals . » , 815 Comparison of the Apparatus of Taste in Man sith that of bi weds . 8lb Cuarrer III.—Apparatus of Smell . a : 3 : 815 Cuarrer IV.-—Apparatus of Vision P : 816 Article 1—Essential Organ of Vision, or Globe of the Eye ; 817 Membranes of the Eye . : 3 ‘ : 817 1. The Sclerotica . i : : . : 817 2, The Transparent Cornea . : : 819 3. The Choroid Membrane ; : - : 820 4. Thelris. 7 : : : 3 - . 822 5. The Retina « ‘ , é : 824 The Humours of the Eye ‘ ‘i - 826 1. Crystalline Lens 2 , 7 . 826 2. Vitreous Humour . : ® 5 . 827 3. Aqueous Humour : . 827 Article 11.—Accessory Organs of the Apparatus of Vision : ; 828 Orbital Cavity . % 828 Motor Muscles of the ‘Gloke af the Eye . 4 : . 828 Protective Organs of = Eye : : F 830 1. Eyelids 7 ‘ : ; . 830 2. Membrana Nictitans : : : ; ‘ 833 Lachrymal Apparatus. 834 Differential Characters in the Visttel Apparotis of other then Soliped Animals . : 835 Comparison of the Viena Apparatus of Man mah that of Sesiuiale : . 836 3 xxxiv TABLE OF CONTENTS. Cnarter V.—Apparatus of Hearing ; : ° Article 1—Internal Ear, or Labyrinth Bony Labyrinth : 7 1. The Vestibule B 7 é , 2. The Semicircular Canals F ‘ é . 3. The Cochlea . The Membranous Labyrinth . 1. The Membranous Vestibule 2s The Membranous Semicircular Canals . . The Membranous Cochlea Liquids of the Labyrinth Distribution and Termination of the Saito Nerve i in the Membranous Labyrinth . F . . . Article 1.—Middle Ear, or Case of the Tympanum . Membrane of the Tympanum F . The Promontory, Fenestra Ovalis, Fenestra Rotinila, . The Mastoid Cells ‘ . Chain of Bones of the Middle Ear . Mucous Membrane of the Tympanic Case , Eustachian Tube . Guttural Pouches Article 11.—The External Ear External Auditory Canal The Concha, or Pavilion 1. Cartilaginous Basis of the Couche 2. Muscles of the External Ear : 8. Adipose Cushion of the External Ear 4. Integuments of the External Ear 7 Differential Characters in the Auditory Apparatus of other than Boliped Animals ‘Comparison of the Auditions Appartus of Man with that of Ayia TEP WON BOOK VIII. GENERATIVE APPARATUS, ‘Cuaprer I.—Genital Organs of the Male : P : ‘ The Testicles, or Secretory Organs of the Semen . 1. Description of the Vaginal Sheath 2. Description of the Testicles . : Excretory Apparatus for the Semen . 1. The Epididymis and Deferent Duct é 2. The Vesiculee Seminales and Ejaculatory Ducts 8. The Urethra 4. The Glands Raneued to the Utethinal Canal 5. The Corpus Cavernosum 6. The Penis Differential Characters in the Male Genital Oronna of other thaw | Soliped Mammals Comparison of the Genital Omens of Man with those of Animals Cuarter II.—Genital Organs of the Female 1. The Ovaries . 4 2. The Uterine Cornua, “Fallopian Tubes, or Oviduets 3. The Uterus . . A : . PAGE $37 837 837 837 837 837 838 838 839 839 840 840 840 841 842 842 842 844 844 844 846 846 846 846 847 850 850 850 850 851 851 852 853 858 858 860 861 864 864 865 867 871 872 872 876 877 TABLE OF CONTENTS. 4, The Vagina 5. The Vulva 6. The Mamme Differential Characters in the Fonale Genital Organg of other than Soliped Mammals . Comparison of the Genital Organs of “Woman with those of Domesticated Female Animals Cuaprter III.—Generative Apparatus oe Birds 1. Male Genital Organs 2. Female Genital Organs . BOOK IX. EMBRYOLOGY. Cuaprer I.—The Ovum and its Modifications after Impregnation Article 1—The Ovum Article 11.—Modifications in the Oven antl the Sepeetanes of the 3 Embryo s Article 11.—Development of the Blastodermic Lamine External Lamina Middle Lamina Internal Lamina Cuapter IJ.—The Feetal Envelopes of Salted 1. The Chorion 2. The Amnion 3. The Allantois 4, The Umbilical Vesicle 5. The Placenta. 6. The Umbilical Cord . Differential Characters in the Annexes of the Feetus of other Dotaesticated Animals than Solipeds Comparison of the Annexes of the Human Foetus with those of the Footus a Animals Cuapter ILE —Development of the Footus Article 1.—Formation of the Embryo Development of the Chorda Dorsalis and Vecisweil Taming Development of the Lateral and Cephalic Lamine : . Article 11.—Development of the Various Organs of the Animal Economy Development of the Nervous System Development of the Organs of Sense Development of the Locomotory Apparatus Development of the Circulatory Apparatus . . Development of the Respiratory Apparatus d . Development of the Digestive Apparatus : . Development of the Genito-urinary Apparatus . P : . Cuaprer IV.—The Ovum of Birds ‘ : . ° r Index . i é i F 3 é S 5 XXKV PAGE 880 882 884 886 888 889 889 889 890 890 890 892 893 893 894 895 895 896 896 899 899 900 901 904 905 905 905 905 907 907 908 911 914 918 919 922 925 927 my fe OMAR HOND EE TABLE OF ILLUSTRATIONS. . Skeleton of the Dog . Skeleton of the Pig . Skeleton of the Horse . Skeleton of the Cow . Skeleton of the Sheep . . Vertical section of bone . Minute structure of bone . Lacunix, or osteoplasts of osseous agen . Cartilage at the seat of ossification . Elements of a vertebra . Atlas, inferior surface r 7 ‘ . A cervical vertebra é ‘ ‘ . The axis or dentata, lateral view . Type of a dorsal vertebra, the fourth . Upper surface of lumbar vertebree . Lumbar vertebra, front view . Lateral view of sacrum . Horse’s head, front view . Anterior bones of the head of a ftobus at hiv . Posterior bones of the head of a foetus at birth . Posterior aspect of Horse’s skull . Antero-posterior and vertical section of the Horse’ 8 head . Longitudinal and transverse section of the Horse’s head . Inferior maxilla . Hyoid bone ‘ . Lateral view of the Horse’s skull ‘ - . Ox’s head, anterior aspect ‘ : . Ram’s head, anterior aspect . Ox’s head, posterior aspect . Median and vertical section of the Ox’ 8 head : . Head of the Pig, anterior aspect . Head of the Pig, posterior aspect . . Head of Dog, anterior aspect . . Dog's head, posterior aspect . Front view of the human cranium ‘ . External or basilar surface of human skull : . The sternum . ‘ ‘ ; . Typical ribs of the Horse . 5 . ° . Thorax of Man, anterior face . . . : . Right scapula, outer surface é e . PAGE Chauveau . 7 Chauveau . T Original. 8 Original 9 Chauveau . 9 Carpenter . 18 Carpenter . 14 Carpenter . 14 Carpenter . 17 After Owen. 19 Original . 22 Original . 22 Original 23 Original . 24 Chauveau . 26 Original . 26 Original. 27 Original . 83 Chauveau . 88 Chauveau 41 Original . 46 Chauveau. 49 Chauveau . 50 Chauveau . BL Chauveau . 53 Original 55 Chauveau . 56 Chauveau . 57 Chauveau 58 Chauveau . 59 Chauveau . 60 Chauveau . 61 Chauveau . 62 Chauveau 63 Wilson i 64 Wilson i 65 Chauveau 66 Chauveau . 68 Wilson . WW Original . 72 TABLE OF ILLUSTRATIONS. . Antero-external view of right humerus . Posterior view of right humerus . External face of the radius and ulna . Right fore-foot of a Horse . Posterior view of the right carpus . Front view of right carpus . Posterior view of right metacarpus . Lateral view of the digital region: outside of right litn . Posterior view of front digital region . . Plantar surface of third phalanx . Navicular bone . Fore-arm and foot of the Ox, jrontt view . Fore-arm and foot of the Dog, anterior face . Human scapula, external aspect . Right human humerus, anterior surface . Human arm bones, front view . Palmar surface of left human hand . The Coxe, seen from below . Pelvis, front view . Pelvis, lateral view . Left femur, anterior view . Left femur, posterior view . Section of left femur, showing its structure . Posterior view of right tibia . Left hind foot, external aspect . Left hock, front view R . . Left hock, internal aspect . . Posterior aspect of left metatarsus E . Human pelvis, female . Right human femur, anterior aspect A Human tibia and fibula of right leg, anterior agpect . Dorsal surface of left human foot . . Skeleton of a Fowl . Cephalic vertebra of the Toe . Plans of the different classes of artioulations . . Section of branchial cartilage of Tadpole . . Fibro-cartilage . White or non-elastic fibrous tisaue . Yellow or elastic fibrous tissue . Intervertebral articulations . Atlo-axoid and occipito-atloid articulations ; . Temporo-maxillary articulation . Articulations of the ribs with the vertebra, upper pian’ . Articulations of the ribs with the vertebrae, inferior plane . Scapulo-humeral and humero-radial articulations, external face . Carpal articulations, front view . Lateral view of the carpal articulations . Section of inferior row of carpal bones, and metacarpal. and sus- pensory ligament . Posterior view of metacarpo-phalangeal and interphalangeal articulations . Sacro-iliac and coxo-femoral sereoniatinnd. . Femoro-tibial articulation . Ligaments attaching the three bones of the leg . Buisnihi and Bouchard XXXViL PAGE Original 73 Original 74 Original 76 Original TT Original 80 Original 80 Original 81 Original 83 Original 83 Original 84 Original . 86 Chauveau . 87 Chauveau . §&8 Wilson 89 Wilson 90 Wilson 90 Wilson 91 Chauveau . 92 Original 93 Original 94 Original 99 Original 99 Original 100 Original 101 Original 103 Original 104 Original 104 Original 105 Wilson 108 Wilson 109 Wilson 109 Wilson 109 Chauveau . 113 Lavocat 120 122 Carpenter . 124 Wilson 124 Carpenter 125 Carpenter . 125 Chauveau 133 Chauveau 137 Chauveau . 138 Chauveau . 140 Chauveau . 140 Chauveau . 145 Chauveau . 150 Chauveau . 151 Chauveau . 155 Original 156 Chauveau . 161 Chauveau . 164 Chauveau . 167 xxxviti TABLE OF ILLUSTRATIONS. . Tarsal articulations, front view . Articulations of the tarsus, lateral view . Ultimate fibril of muscle é . Striated muscular tissue fibre 3 3 . Termination of nerves in muscular fibre . Distribution of capillaries in muscle . Termination of nerves in an elementary musoular fibre . Striated fibre of muscle during contraction . Lateral view of the neck, superticial muscles . Superficial muscles of the neck and spinal region of ‘the back and loins . Lateral view of the neck, middle lager of muscles . Cervical ligament and deep muscles of the neck . Muscles of the spinal vee of the neck, back, and loins . Deep ditto ‘ . Muscles of the back and cervix of ‘Man . Muscles of the sublumbar, patellar, and internal eral regions: . Deep muscles of the sublumbar region . Superficial muscles of the face and head . 2 . Hyoideal and pharyngeal regions : ¢ ‘ ; . Superficial muscles of the Ox’s head . Muscles of the human head : . Muscles of the axillary and cervical regions : . . Axillary and thoracic muscles : Z A F . Muscles of the inferior abdominal region . . Muscles of the anterior aspect of the body of Man . Diaphragm, posterior face ; : . External muscles of the anterior limb . Muscles of anterior aspect of Man’s upper arm . Internal aspect of left anterior limb . Deep muscles on external aspect of 1ight anterior fey . Muscles of the fore-arm of the Ox . Tendinous and ligamentous apparatus in the digital : region of the Ox . . Muscles of the ibis -arm antl paw of the Dog : . Superficial muscles of human fore-arm . Deep layer of superficial muscles of human fore-trm . Muscles of human hand ; . Superficial muscles of the croup and tigi . Muscles of the sublumbar, patellar, and internal craral regions . Coceygeal and deep muscles surrounding the coxo-femoral articulation . Superficial muscles of the croup and thigh i in the Cow . Muscles of the anterior femoral region in Man . Muscles of the posterior femoral and gluteal region in Man . External deep muscles of right posterior limb . Flexor muscle of metatarsus i . Muscles on inner aspect of left posterior limb . External muscles of the leg of the Ox . : . Muscles of the human leg, anterior tibial region . Superficial posterior muscles of the human leg . First layer of plantar muscles of human foot . Third, and part of second layer of plantar muscles of Trema foc PAGE Chauveau . 169 _Chauveau . 171 Bowman . 178 Bowman . 178 Kiihne 179 Berres . 180 Beale . 180 Bowman . 181 Original . 188 Chauveau . 190 Original . 192 Chauveau . 194 Chauveau 204 Chauveau . 207 Wilson . 210 Chauveau . 213 Chauveaw . 214 Original . 218 Original . 226 Chauveau . 228 . Wilson . 231 ‘Chauveau . 232 Original 234 Chauveau . 248 Wilson . 245 Chauveau . 247 Chauveau . 250 . Wilson » 255 Original . 257 Original . 260 Chauveau . 270 Chauveau . 271 Chauveau . 273 Wilson . 275 Wilson . 275 Wilson . 279 Original . 282 Chauveav, . 290 Chauveau 293 Chauveau . 294 Wilson . 296 Wilson . 296 Original . 299 Chauveau . 800 Original . 303 Chauveau 307 Wilson . 810 , Wilson . 3810 Wilson 312 Wilson . 812 Flas, 143. 144. 145. 146. 147. , 148. 149. 150. 151. 152. 153. 154. 155. 156. 157. 158. 159. 160. 161. 162. 163. 164. 165. 166. 167. 168. 169. 170. Ii 172. 173. 174 175. 176. 177. 178. 179. 180. 181. 182. 183. 184. 185. 186. 187. 188. 189. 190. 191. 192. 193. 194. 195. TABLE OF ILLUSTRATIONS. Squamous epithelium trom the mouth Columnar epithelium . Columnar ciliated epithelium z Conical villi on mucous membrane of small intestine Fusiform cells of smooth muscular fibre. ; Hard and soft palate Muscles of the tongue, soft alae, and pherpns Lobe of racemose gland from the floor of the mouth Follicular gland Median longitudinal section of the head and upper part of neck Section through the fang of a molar tooth Transverse section of enamel 5 : Magnified section of a canine tooth . : ‘ Theoretical section of dental sac of permanent incisor Section of dentine and pulp of an incisor tooth Dentition of inferior jaw of Horse . Incisor teeth of Horse, details of structure Profile of upper teeth of the Horse 7 Transverse section of Horse’s upper molar : r The teeth of the Ox Ox’'s incisor tooth Incisor teeth of a Sheep two years old Teeth of the Pig ; General and lateral view of the Dog’s teeth . Anterior view of the incisors and canine teeth of Dog . Section of the human face . Lobule of parotid gland Capillary network of follicles of parotid: piand Termination of the nerves in the salivary glands Inferior aspect of head and neck Maxillary and sublingual glands Pharyngeal and laryngeal region . Median longitudinal section of head and appear part of jnedte Muscles of the pharyngeal and hyoideal regions Human pharynx 3 ‘ Transverse vertical section of head and neck Pectoral cavity and mediastinum Theoretical transverse section of abdominal cavity ‘ Theoretical, longitudinal, and median section of abdominal cavity The abdominal cavity, with the stomach and other eiganig: Stomach of the Horse . Interior of the Horse’s stomiéls Muscular fibres of stomach, external and middle layers Deep and middle muscular fibres of stomach : Peptic gastric gland . ‘ . : . : Portion of a peptic caecum : ‘ Mucous gastric gland . Capillaries of mucous membrave of stomach Stomach of the Dog. . 5 : Stomach of the Ox ‘ ‘ . Interior of the stomach of Husiinanta z Section of the wall of the omasum of Sheep . 7 Section of a leaf of the omasum 6 : $ Xxxix PAGE Wilson 327 Kolliker 827 Carpenter . 327 Wilson 328 Bowman 328 Chauveau . 333 Chauveau . 3388 Kolliker 339 Kélliker 339 Original . 341 Carpenter . 345 Carpenter . 346 Wilson 347 Chauvreau 348 Carpenter . 349 Chauveau . 350 Chauveau . 351 Chauveau . 353 Chauveau . 354 Chauveau . 357 Chauveau . 358 Chauveau . 359 Chauveau . 360 Chauveau . 361 Chauveau . 361 Quain 362 Wagner 365 Berres 365 Pfliger 366 Original 367 Chauveau . 368 Original 372 Original 373 Original 375 Wilson 377 Original . 378 Chauveau . 379 Chauveau . 382 Chauveau . 383 Original 386 Chauveau . 387 Chauveau . 388 Chauveau . 390 Chauveau . 390 Kélliker 391 Kélliker 391 Kélliker 392 Carpenter . 392 Chauveau . 393 Chauveau 394 Chauveau . 395 Chauveaw . 398 After Chauveau 399 TABLE OF ILLUSTRATIONS. . Longitudinal section of a large papilla from the omasum . Villi of human and Sheep’s intestine . . Portion of Brunner’s gland . Section of mucous membrane of small intestine . Section of mucous membrane of large intestine . Injected villi of intestine : . . z. Blood-vessels in Peyerian glandule . Diagram of origin of lacteals in villi 3 ; . General view of the intestines of the Horse, right side . General view of the Horse’s intestines, inferior aspect . . The colon of the Horse. . Plan of the colon . General view of the intestines of the Ox i . Intestines of the Dog . . Human intestines . . Abdominal cavity, with the liver avid oer organs . Portion of a hepatic column, with secreting cells . Biliary capillaries and ducts . Bloud-vessels in lobules of liver . Section of lobules of liver, with igualdinane veins . Excretory apparatus of the Horse’s liver . . Malpighian corpuscles attached to splenic artery . Splenic corpuscle from the spleen of Ox . Liver of the Dog, with its excretory apparatus . Under surface of the human liver . . General view of the digestive apparatus of a fowl . Cartilages of the nose . Transverse section of the head of Hoike . Longitudinal section of the head, and upper part of neck . . Cells of the olfactory mucous membrane . . Fibres of olfactory nerve . Superior face of larynx - : - . Inferior face of larynx. 3 ; . Postero-lateral view of larynx . . The respiratory organs, inferior aspect . Ciliated epithelium fot the trachea . . Bronchial tube, with its bronchules ; . Mucous membrane of a bronchial tube . The pectoral cavity and mediastinum . Theoretical section of thoracic cavity, behind the heart . Theoretical section of thoracic cavity, at root of lungs - Theoretical section of thoracic cavity, in front of right ventricle Chauveau . . Plan of a pulmonary lobule . Air-cells of lung . . Capillaries and air-cells ee lung . Lung of the Sheep, inferior view . : iuecaey dungs and heart ‘ . Gland vesicles of thyroid . Portion of thymus of calf . Course and termination of ducts in tiem anil of calf . General view of the air-sacs in the duck : . General view of the yenito-urinary apparutus in the male . - Horizontal longitudi. 1 section of the Horse’s kidney . . Section of the cortical . ~bstance of the kidney : Chauveau . Teichmann. Thomson Teichmann. Teichmann. Kolliker Kolliker Funke After Chauveau Chauveau . Original Chauveau . Chauveau . Chauveau . Wilson Original Leidy Irminger and Frey Kiernan Kiernan Chauveau . Kolliker Kélliker Chauveau . Wilson. Chauveau . Chauveau Chauveau . Original Clarke and Schultze Ecker ‘ After Chauveau After Chauveau - Original Original Kolliker Heale Heale Chauveau . Chauveau . Chauveau . . Waters Kélliker Carpenter Chauveau , Wilson Kélliker Kolliker Wilson Chauveau . Chauveau . Chauveau Ecker PAGE 399 403 403 404 405 405 . 406 406 408 409 410 411 415 416 417 421 423 423 424 424 425 430 430 433 434 436 440 442 443 445 446 452 452 454 458 459 465 468 488 287. 288. . Arteries of the face and head of Man . Roots of the superior jugular vein, with its ealindsial affluents 290. 291, 292. 293. 296. 297. 299. 300. 302. TABLE OF ILLUSTRATIONS. . Course of the uriniferous tubuli - Diagram of the circulation in the kidney . . Transverse horizontal section of kidney . The kidneys and bladder in the foetus of Solipeds . . Right kidney of Ox, upper and external face . . Left kidney of Ox, internal and inferior face . The calices in left kidney of Ox . Theoretical plan of the circulatory system . . The heart and principal vessels, left face . The heart and principal vessels, right face . Right side of the heart laid open 5 : 5 . Section of the heart at the level of the valves e . Left cavities of the heart laid open. ‘ . Anastomosing muscular fibres of heart . Epithelium of the endocardium : . Human lungs and heart, front view . Web of Frog’s foot, showing blood-vessels and hele eeinnnaed 7. Epithelial cells of blood-vessels . Fenestrated membrane from the carotid artery of the Horse 9. Coarse elastic tissue from pulmonary artery of the Horse . Transition of a minute artery of the brain into capillary vessels . Distribution of the great mesenteric artery . Distribution of the small mesenteric artery . Arteries of the stomach in Ruminants . . Upper and general view of the genito- pei: apparatus and . . arteries in the male . Lateral view of the genito-urinary organs in the inal A . Abdominal aorta, with its branches, in Man . The external and internal iliac arteries in the Mare . Principal arteries and veins of the posterior foot . Anterior aspect of iuman leg and foot . Posterior aspect of human leg . Arteries of sole of human foot . . Distribution of the anterior aorta . . Arteries of the fore-foot, seen from behind . Arteries of the human fore-arm and hand . 5. Arteries of the brain . Arteries of the head Réseau admirable of the Sheep, seen in piefile; Réseau admirable of the Ox, posterior face Section of the cranial cavity and spinal canal Veins of the foot . . General view of the veins in the Horse . The vena porte and its roots . ‘ ‘ . Section of a lymphatic rete mirabile Section of lymphatic gland. : . Section of simple lymphatic gland. . Section of the medullary substance of lympnatic winind of Ox Ordinary disposition of the thoracic duct . Double variety of the thoracic duct . Triple variety of the thoracic duct : os Lymphatic system of the Horse - A Be! Hertz Bowman Original Chauveau . Chauveaw . Chauveau . Chauveau . Colin Chauveaw . Chauveau . Wilson Sibson Wilson ~ Kaélliker Kolliker Wilson Wagner Kélliker Kolliker Kolliker Kélliker Chauveau . Chauveau . Chauveau . Chauveau . Chauveau . Wilson Chauveau Chauveau . Wilson Wilson Wilson Chauveau . Chauveau . Wilson Chauveau Chauveau . Chauveau . Chauveau . Heath Chauveau . Chauveau . After Bouley Chauveau . Chauveau . Teichmann. Kolliker Teichmann. Kolliker Colin Colin Colin Colin xli PAGE 488 489 489 492 496 496 496 498 501 502 504 505 507 509 511 514 518 518 519 519 519 530 533 536 539 542 544 546 552 558 558 559 562 568 574 580 583 593 594 595 604 607 614 618 620 631 632 632 633 636 636 636 639 . Nerves of the axilla of Man TABLE OF ILLUSTRATIONS. . Great lymphatic vein and entrance of the thoracic duct . Great lymphatic duct, another variety . Thoracic duct in the Ox . E . A variety of the thoracic duct in the Ox . Another variety of the thoracic duct . A fourth variety of the thoracic duct . . Thoracic duct of small Ruminants. . Diagram of structure of nerve-fibre . Multipolar, or stellate nerve-cell . Ganglion from heart of Frog . . . Bipolar ganglionic cells and nerve-fibres . . Stellate nerve-cell 3 ; . . Structure of ganglionic cells . General view of the spinal cord . Segment of thespinal cord at the cervical bulb . Section cf the spinal cord of the Horse at the lumbar region . Chauveau . . Transverse section of spinal cord of Man at the middle of the lumbar region Cat : . General view of the brain, ‘Appet surface . General view of the brain, lower surface . Superior view of the encephalie isthmus . Lateral view of the isthmus i . Transverse section of the encephalon . r . . Dissection of the medulla oblongata . Median and vertical section of the encephalon . . Section of the cortical substance of the cerebellum . . Antero-posterior and vertical section of the encephalon . Corpus callosum . Anterior portion of the litera vonfielas . Corticle substance of the cerebral ais . Base of the human brain . Muscular fibres, with termination of sitet nerve . . Nerves of the eye F . General view of the superior and ‘nferiol maxillary nerves Chauveau . . Section through the summit of the medulla oblongata . . Origin of the nerves arising from the medulla oblongata . Pneumogastric nerve, with its branches in the neck . Origin and distribution of the eighth pair of nerves in Man Wilson . Distribution of the nerves in the larynx of the Horse . . Deep nerves of the head 7 : . Nerves of the guttural recion in the Ox ‘ Nerves of the face and scalp of Man . External nerves of anterior limb . Nerves of the digit of Horse . Nerves of the digital region of imitate: . Nerves of the palmar face of Dog’s foot . . Nerves of the palmar face of Cat’s foot . Colin ‘ Colin E Colin ; Colin Colin Colin Colin : Carpenter . Ecker . Ecker Ecker Beale P . Beate and Arnold - Colin Fi Colin I. L. Clarke . Longitudinal section through cebuieal bulb of ental cord of the I, L. Clarke Chauveau . Original Chauveau . Chauveau . Chauveau . Solly and Carpenter . Chauveau . Kolliker Chauveau . Chauveau . Chauveau . Killiker Hivscfe and Leveillé Cohnheimn . Chauveau . Carpenter . Toussaint Toussaint . Toussaint . Chauveau . Toussaint . Hirschfeld and Levetlte . Distribution of eighth pair of nerves on left side Hirschfeld and Leveillé . Ganglion of a spinal nerve from the spinal region . : . Nerves of the brachial plexus . Kélliker Chauveau . Chauveau . Bouley Chauveau . Chauveau . Chauveau . Hirschfeld and Leveille . Nerves of the front of fore-arm and hand of Man - Hirschfeld and Leveille 646 647 652 653 654 654 654 654 667 667 669 670 671 673 676 678 680 682 684 687 689 690 693 696 697 699 702 708 714 721 730 731 732 734 738 740 745 746 748 757 759 762 764 766 767 768 769 FIGS. 356. 380. 381. 382. 383. 384. 385. 386. 387. 388. 389. 390. 391. 392. 393. 394. 395. 396. 397. 398, 399. 400. 401. 402. 403. 404. 405. 406. TABLE OF ILLUSTRATIONS, . Lumbo-sacral plexus and internal nerves of posterior limb Posterior portion of the lumbo-sacral plexus Horizontal section of the junction of the wall with the sole of hoof Horizontal sention of wall aaa horny ‘wail waseuine lamin Fibres of ultimate ramifications of olfactory nerves xiii PAGE Chauveau . 771 Chauveau . 773 . External nerves of posterior limb Chauveau . 776 . Lumbar plexus of Man . . Hiadifae and Leveillé 779 . Nerves at the posterior aspect of aria fess Hirschfeld and Leveillé 780 . Nerves at the front aspect of human leg. . Hirschfeld and Leveille 780 . Sympathetic ganglion froma Puppy . F . Sympathetic system of the Horse . . Section of Horse’s skin 3 . Capillary loops in cutaneous papilla . Tactile papilla from the skin . . Interungulate gland of Sheep 2 . . . Branches of cutaneous nerves in skin . ‘ 7 . . Sudoriparous gland . Oblique section of epidermis . . Longitudinal median section of Horse's s foot . Horizontal section of Horse’s foot . Lower surface of the Horse’s foot . . Lateral view of the Horse’s foot . Hoof removed from the foot . Hoof with outer portion of wall removed . Plantar surface of hoof . Horn-cells from the sole of hoof . Constituent elements of the wall 379. Kolliker . 782 Chauveau . 784 Chauveau 793 Bervres » G08 Licker . 794 Owen . 794 Ecker 795 Wagner . 795 Carpenter . 796 Original . 800 Original . 801 Original 802 Original . 83 Leisering . 806 Leisering . 806 Leisering . 807 Leisering . 809 Leisering . 810 Leisering . 811 Leisering . 811 Licker . 816 Cells of olfactory mucous membrane : Claris and Shultze 816 Theoretical section of the Horse’s eye . : Anterior segment of a transverse section of the globe of the aye (human) : Cells from pigmentum aan 5 The eye (human) with the sclerotic coat seo: Muscular structure of the iris . Vertical section of retina . zs Diagram of the structure of the retina : Capillaries in the vascular layer of the retina Muscles of the eye-ball, viewed from above Section of lamina spiralis of the cochlea Section of the cochlea parallel to its axis Right tympanic cavity of Horse’s ear Bones of the middle ear of the Horse . Muscles of the ear Human testis, injected with menu Vertical section of the Horse’s testis Internal genito-urinary organs of the foetus of a Mare. Spermatozoa of various animals Diagram of the testicle Superior view of the genito-urinary aieaae Longitudinal section of the free extremity of the Horse’s penis Sections of the urethra of the Ox at different points Penis and muscles of the sheath of the Bull Section of human pelvis : Chauveau 818 Wilson < 821 Carpenter . 822 Holden . 823 Kolliker . 823 Miller . 825 Krause . 826 Berres . 826 Original . 829 Carpenter’. 838 Breschet . 838 Chauveau . 841 Lavocat . 843 Original . 848 Lauth 854 Chauveau . 855 Chauveau . 857 Carpenter . 858 Holden . 859 Chauveau . 860 Chauveau . 866 Chauveau . 868 Chauveau . 869 Gray . 871 TABLE OF ILLUSTRATIONS. ~ Ovarium of the Rabbit . Constituent parts of mammalian ovum, "entire . Constituent parts of mammalian ovum, ruptured . Formation of the corpus luteum . Generative organs of the Mare, isolated F . Generative organs of the Mare, in situ . Termination of milk-duct in cluster of follicles . Ultimate follicles of mammary gland, with secreting cells . . Microscopic appearance of milk . Human uterus, with its appendages 5 . First stages in segmentation of mammalian ovum . Later stages in segmentation . Section through embryo of the Chick, first cee of fenton . Plan of early uterine ovum . Diagram of ovum at formation of tne amnion . . Exterior of the chorial sac, Mare i . Fecundated egg, showing formation of amnion reel allantots . Fecundated egg, with amnion nearly completed. ‘ . Foetus of the Mare, with its envelopes. 5 . Portion of ultimate ramifications of umbilical vessels ‘ . Portion of one of the feetal villi . Equine foetus, opened on left side to show manila yeuels . Blood-vessels in liver of an equine foetus at mid-term . Liver of a Lamb at birth . . Diagram of an early human ovum ‘ : . Diagram of a human ovum in second month . . Early stages in the development of a Fowl . Transverse section of embryo of Chick on third day . Plan of development of eye . Origin of encephalic centres in utien anbipe of sixth week . Plan of chorda dorsalis at period of formation of embryo . Plan of vertebra at an early period of development . Head of a foetal Lamb, showing Meckel’s eau eee . Plan of first system of vessels, embryo . . . Embryonic heart at an early period, anterior view . Ditto, seen from behind z Heart of an equine foetus . . Plan of the aorta and its arches at an euly pete . Plan of the circulation in the human embryo, side view . First appearance of the lungs . . Embryo of Dog at twenty-five days . Origin of liver from intestinal wall of embryo Chick . Urinary and genital apparatus in embryo Chick . Section of Fowl's egg . . . ‘3 . Pouchet Coste Coste Pouchet Chauveau . Chauveau . . Sir A. Cooper Lebert Funke Wilson Coste Coste Kélliker Wagner Wagner Chauveaw . Dalton Dalton Chauveau . Carpenter Ecker Chauveau . Colin Colin Wagner Wagner Hualey Kolliker Kélliker Wagner Kolliker Kolliker Hualey Kélliker Kolliker Kélliker . Chauveau . Kélliker Coste Wagner Bischoff” Miiller Miiller Allen Thomson PAGE 874 875 875 875 878 881 885 885 885 888 891 891 893 894 894 895 896 896 898 899 900 901 902 902 904 904 906 908 909 910 912 912 913 914 ° 915 915 916 917 918 919 919 922 922 925 THE COMPARATIVE ANATOMY OF THE DOMESTICATED ANIMALS. GENERAL CONSIDERATIONS. DEFINITION AND DIVISIONS OF ANATOMY. Anatomy is the science of organisation; it studies the structure of animated beings when these have been deprived of life. It comprises two grand divisions: physiological anatomy, which describes healthy organs, and pathological anatomy, whose object is the description of diseased organs. Physiological anatomy, in its turn, embraces :— 1. General anatomy, which is occupied with the analogous matters or tissues of the animal body, with regard to their texture, and their physical, chemical, and physiological properties, irrespective of the organs in which these tissues exist. The particular study of the anatomical elements entering into the composition of the tissues is named histology. 2. Descriptive anatomy, which studies the situation, form, and relation of organs, as well as the relative arrangement of the various tissues composing them, with the exception of the structure and properties of these tissues. If this study be devoted to a single species, it is designated special anatomy. Example: human anatomy, or anthropotomy ; the anatomy of the Horse, or hippotomy. When descriptive anatomy embraces the study of the organisation of the entire animal kingdom, and examines the differences which characterise the same organ or the same series of organs in each class, family, genus, or species, it is named comparative anatomy. Restricted to the domesticated animals, this study constitutes veterinary anatomy. Philosophical or transcendental anatomy differs from comparative anatomy, inasmuch as it indicates the analogies of organs or apparatus, in order to exhibit the simplicity of Nature’s plan in the general laws of organisation. Finally, if descriptive anatomy is limited to denoting the relations existing between the various organs of a region, particularly with a view to the performance of operations and the diagnosis of external diseases, it takes the names of topographical, regional, or surgical anatomy. 2 GENERAL CONSIDERATIONS. ENUMERATION AND CLASSIFICATION OF THE SPECIES OF DOMESTICATED ANIMALS, The object of this book is the study of veterinary anatomy. The animals of which it treats belong to the mammiferous class and to that of birds. ; ; Me sack The domesticated mammals of our regions have their representatives in a large number of orders. Thus, we find among them :— 1. Of the carnivora, the Dog and Cat ; 2. A rodent, the Rabbit ; - 3. A pachyderm, the Pig ; ; ; 4. Of solipeds, the Horse and Ass; the produce of the male ass with the mare, i.e., the Mule, and that of the horse with the female ass, known by the name of Hinny ; 5. Of ruminants, the Ox, Sheep, and Goat, With regard to poultry, they range themselves :-— 1. In the gallinaceous order, the genera to which the common owl, guinea fowl, turkey, and pigeon belong ; 2. In the order of palmipeds, the geese and ducks. Girard has proposed a special classification for the domesticated mammals, based upon the number of digits terminating each of their limbs, and has defined four categories: the first comprises the horse, ass, mule, and hinny, which take the name of monodactyles, because their digital region is composed of a single digit; in the second, under the denomination of didactyles or bisulcate animals, those with two digits, such as the ox, sheep, and goat; in the third, or regular tetradactyles, is found ranged the pig, each of whose limbs shows four digits; lastly, the dog and cat, which most frequently have four digits on the posterior members and five on the anterior ones, and. form the class of irregular tetradactyles, This nomenclature will not be followed here, as it is opposed to the general laws of organisation ; philosophical anatomy has, in fact, demonstrated that there are really no veritable monodactyles, didactyles, etc., all are materially. or virtually pentadactyles. It is therefore considered better to keep to the classification established by zoologists, because it prevents confusion in scientific language, which should always be the same for everyone engaged in the study of anatomy. The regimen. and habits of the domesticated animals bring about differ- . ences in their organisation which appear very great at first sight, though in reality they are not so profound as they seem. In order to study the descriptive anatomy of all these animals, we will not pass them in review, one after another, giving for each the description of every organ; but shall take a type, which will most frequently be the Horse, and briefly compare all the others with it, cases, we will describe, without leaving the Horse, all apparatus ; afterwards the same organs in the other species will be studied in the same order. In this comparison, the animals will be generally classed according to their domestic value: though exceptions will be made to the rule which has been instituted by our predecessors, whenever any advantage 1 point of concision or perspicuity is likely to be obtained. . GENERAL CONSIDERATIONS, 3 GENERAL IDEA OF THE ORGANISATION OF ANIMALS, Order followed in studying the Various Apparatus. a bodies of animals, formed of organised matter, contain fluids and solids. The fluids are very abundant in the animal economy; not only do they fill certain vessels constructed for them, but they also impregnate all the solid parts of the body. Their importance is very great, for without them the organic solids would perish; an element deprived of humidity is an element deprived of life. Fluids vary in their nature and composition. Apart from those that the solids imbibe, there is not one which is completely amorphous. In the midst of a liquid holding organised matter in solution there are always elements which will be referred to hereafter. Examples: the blood and lymph. In studying the organic solids, we will proceed from the simple to the complicated. Exemenrs.—Solid organised matter presents itself in the form of more or less voluminous particles, in every instance invisible to the naked eye, and named the anatomical elements. They may be reduced to three principal: the granule,-cell, and fibre. Granules.—These are the smallest known elements. They may be held in suspension in animal fluids, remain free among the other elements, or be enclosed in the interior of cells. Their nature is not always the same: they are proteic or fatty. They are called pigmentary when they exhibit a brown colour. Cells.—The cell is pre-eminently the anatomical element. It may be represented to the mind as a microscopic collection of a nitrogenous substance, viscid or slightly granular, and endowed with extreme vitality. Frequently in the midst of this protoplasm (for so it has been called), there is perceived a nucleus provided with a nucleolus, and at its periphery an enveloping membrane is discovered. It must not be forgotten that this membrane, and even the nucleus, is necessarily a constituent portion of the cell. The cell lives like an entire organism: it feeds, grows, multiplies, absorbs, secretes, moves, etc. It behaves like a complete animal, though it be a microscopic one. The form of the cell varies greatly, as does its volume and its nature. It has therefore received various names. There are round, polyhedral, fusiform, stellate, and other shaped cells. Some have a diameter of 1-12000th part of an inch, while others are 1-2000th part. Cells multiply in various ways: Ist, by the division of the nucleus and segmentation of the protoplasm in the interior of the enveloping membrane (endogenous multiplication); 2nd, by constriction, the division of the nucleus, protoplasm, and enveloping membrane ( fisstparous multipli- cation) ; 3rd, by a kind of bulging or swelling of the enveloping membrane, and strangulation and separation of the enlargement thus formed (gemmation). mee : = A large number of cells only temporarily remain in this condition. In consequence of modifications that cannot be referred to here, they are con- yerted into fibrille or other elements, in which it is difficult to recognise them. Others maintain the cellular form: then they are developed, live, and die in several ways. Sometimes they are worn by the contact of foreigr 4 GENERAL CONSIDERATIONS. bodies, as on the surface of the skin; at other times they become dissolved, as in some glands; finally, at other periods they submit to fatty degeneration, which gradually brings about their complete destruction. : The permanent cells have been arranged according to the following denominations :— 1. Hematies or red globules, which are found in a state of suspension in the blood; they are round or elliptical. . Leucocytes, or white globules, which float in the blood, lymph, and chyle. . Connective cells, comprising the connective cell properly so-called, the plasmatic cell, and the adipose cell. . Medullary cells, forming the principal elements of the marrow of bones (myeloplaxes and medullo-cells). . Contractile cells, which constitute the basis of muscular tissue. . Nerve cells, met with in the cerebro-spinal centres and the ganglia of the cerebro-spinal and sympathetic systems. . Epithelial cells, comprising the epithelial cells properly called, situated on the surface of the skin and mucous membranes, and the glandular cells. Fibres.—A fibre is an elongated anatomical element, of variable dimensions and composition. It may be very fine and represented by a single line, or thicker and marked by two lines more or less apart from one another. It is homogeneous throughout, or the contents are distinct from the envelope. The vitality of fibres is not to be compared with that of cells; after they are formed, they can only be nourished, and cannot multiply of themselves. In the animal economy four kinds of fibres are distinguished :—the connective fibre, elastic fibre, muscular fibre, and nervous (or nerve) fibre. Tissurs.—The elements that have now been rapidly described, in becoming united and grouped in different fashions, form the tissues. Some tissues are composed of one kind of element; these are the simple tissues. Example :—The epithelium. ® The majority, however, are formed by the union of several different elements: these are the composite tissues. Example :—Nervous tissue. It is also remarked that there are tissues in which exists a fundamental intercellular substance, and others in which this is absent. The latter are few in number, for the vessels and nerves may, in certain tissues, be considered as intercellular substance. The anatomical, physico-chemical, and physiological characters of the tissues repeat, as might easily be inferred, the anatomical, physico-chemical, and physiological properties of the elements entering into their formation. Only four fundamental tissues are recognised, basing them on the morphological, chemical, and physiological characters of the elements. In the first place, the tissue of the conjunctival substance should be noticed ; this, in consequence of some differential characters, may be divided into :— gelatinous tissue, conjunctival (or connective) tissue, cartilaginous tissue, and bony tissue. Then comes the cellular tissue, formed entirely of persistent cells. It comprises the epithelial tissue and the glandular tissue. The cells of the epithelial tissue may affect different arrangements. If they are disposed in a single row, there results a simple epithelium ; if they are superposed it is a stratified epithelium. According to the form of the cells of the superficial layer, the epithelium is polyhedral, pavement, cylindrical, or spherical, In certain points, these superficial cells are furnished with Vibratile filaments; they are then designated vibratile (or ciliated) epithelium. “I DD or e co bo GENERAL CONSIDERATIONS, 5 In the third place, is the muscular tissue, which may be divided into striated and non-striated (or striped, and non-striped or sthooth) fibres. Lastly comes the nervous tissue, which offers two aspects: the white and grey substance. The first is entirely formed by nerve fibres, and the second by fibres and nerve cells. ; Orcans.—The term organ is given to an agglomeration of tissues possessing a determinate form, and having a function to fulfil. Organs are therefore composed of tissues, as the tissues themselves are constituted by anatomical elements. All animal organs are enclosed between two membranes named limitary or tegumentary membranes, which are continuous with one another at the margin of the natural openings. These are the skin and the mucous membranes, in whose composition is included a layer of connective tissue covered by an epithelium. Organs are distinguished into those which are solid, and those which are hollow. Among the first, a certain number act as supports: such are the organs formed by the connective tissue, and particularly the cartilages and bones. Others are destined to produce movements: these are the two kinds of muscles. The action of the muscles is communicated directly to the organs that are to be moved, or it is transmitted through the medium of other organs, such as the tendons and aponeuroses. The central nervous organs, nerves properly so called, and the vascular glands, belong to this group of solid organs. With regard to the hollow organs, they are everywhere covered by the internal, tegumentary, or mucous membrane. Examples:—the lungs and stomach. There must also be included the vessels formed by elastic and contractile membranes arranged as canals, in which the blood and lymph circulate; and, lastly, the serous membranes, which line the interior of the splanchnic cavities, and cover the surface of the organs contained in them. Apparatus.—Organs are very numerous in the animal economy, and in, order to study them profitably it is necessary to classify them in a methodi- cal manner, according to their physiological affinities. Consequently, there have been collected into a single category all those organs which are destined to achieve the same physiological finality, and to such a group has been given the name of apparatus. An apparatus is, then, an assemblage of all those organs of an animal which concur to the same end, and which serve for the accomplishment of the same function. We will successively describe, in the following order, the different appa- ratus of which the organism is composed :— 1. Locomotory Apparatus ; 2. Digestive Apparatus ; 3. Respiratory Apparatus ; 4. Urinary Depurative Apparatus ; . Circulatory Apparatus ; . Innervatory Apparatus ; . Sensory Apparatus ; . Generative Apparatus ; CO MTS Or This description will be terminated by a brief exposition of the evoluticn of the fetus and its appendages. : 4 BOOK I. Locomotory APPARATUS, Tux locomotory apparatus is composed of all those organs which minister to the movements an animal may execute. It is certainly one of the most im- portant in the economy, from the number and volume of the pieces which enter into its formation, and by the necessary co-operation that it affords the other apparatus in the performance of the physiological acts which are allotted to them. It is constituted of two kinds of organs; the bones and muscles. The bones, hard and resisting, stony in appearance, are real inert levers, joined to each other by firm and movable articulations, which permit their playing upon each other with the greatest facility, at the same time maintaining them in their relative positions. The muscles, grouped around the bones and attached to them, are soft organs which possess the property of contrac- tion, under certain determinate conditions and of involving in that move- ment the bones to which they are fixed by their extremities. The first are altogether passive in their motion, while the second are really the active organs of locomotion—the powers intended to move the bony levers. We will treat successively of :— 1, The study of the bones, a particular branch of descriptive anatomy which has received the name of osteology ; 2. The study of the articulations, or arthrology , 8. The study of the muscles, or myology. FIRST SECTION, THE Bones. CHAPTER I, THE BONES IN GENERAL. Bonzs, properly speaking, are only to be found ir vertebrate animals, and constitute their principal zoological character. In the animal body they form an internal framework which consolidates the entire edifice, and gives it its general form and dimensions. It is advantageous, before commencing a particular description of each bone, to survey them ina general manner. This study comprises: 1, The description of the skeleton 3 2, The summary indication of the general principles which should be known in order to com- prehend the details of the special descriptions. THE SKELETON, 7 Articte I.—Tuer SKELETON, The whole of the bones, considered in their natural relations to each other, constitute the skeleton. In order to prepare the skeleton of any animal, it is sufficient to free it from the soft parts surrounding it. The skeleton should be designated natural, if in this operation the ligaments SKELETON OF THE PIG. 8 THE BONES. that naturally join the various pieces together are allowed to remain; and artificial if, after these ligaments have been destroyed, it ig necessary to replace them by materials foreign to organisation, such as iron or bras¢ wire. The skeleton is divided into trunk and limbs. The trunk offers for consideration, in the median line, the spine or vertebral column, a flexible stalk measuring the entire length of the animal, * ‘and composed of a series of distinct pieces articulated one behind the other, Anteriorly, this stalk supports the head, a pyramidal protuberance which itself results from the assemblage of a large number of bones. On each side of the middle portion of the spine, there are detached bony SKELETON OF THE HORSE, arches which have received the name of ribs, and which rest direct or indirectly, by their inferior extremities, on a single bone called the sternum. These bony arches in this way circumscribe the thorar. a spacious cavity destined for the reception of the principal organs of re- spiration and circulation. is The limbs, four in number, two antertor and two 1 appendages which support the trunk. Each represents a eek Sided into several rays resting upon one another, and generally forming more or less acute angles. The anterior limbs are each divisible into four principal regions: the shoulder, applied against the front part of the thorax; the arm, which succeeds the shoulder; and the fore-arm and foot. The oad ae? Hage comprise four regions: the haunch or pelvis "which articulates wi ine ; igh, 1 oo the posterior part of the spine; and the thigh, leg, and “HE SKELETON, In birds, the posterior limbs al of support.’ The anterior limb, wings, 9 one assume the function of columns s, formed for flight, constitute the Fig. 4, HT i Field hr FEM Fa A$ Gy) oa a Nt a) \ SKELETON OF THE SHEEP, The number of bones entering into the composition of the skeleton of the domesticated animals, arrived at the adult period of life varies according 10 GENERAL PRINCIPLES APPLICABLE TO to the species. They are apportioned to the regions of the trunk and limbs just mentioned, in the manner indicated in the following table: DESIGNATION. Solipeds.! | Ruminants. Pig. Dog.2 Vertebral Column*® . , . 44 43 42 43 Head? or a ee 28 28 a9 28 Thorakic i 2 4 3 37 27 29 27 Shoulder . 1-2 1-2 1-2 1-2 Arm . \ 1-2 1-2 1-2 1-2 Fore-arm. 2-4 2-4 a ae Fore-foot . . 16-32 20-40 36- 36-7 Pelvis Houle regione 1-2 1-2 1-2 1-2 Thigh . 1-2 1-2 1-2 1-2 Leg . . 3-6 ae 3-6 3-6 Hind-foot | 15-30 | 19- 36-7 32-64 1391 (QA Z bal HEA Articte Il.—Gzxyerat Princrptes APPLICABLE TO THE STUDY OF ALL THE Bones. The description of any bone comprises its name, situation, direction, conformation, structure, and mode of development. Name. The nomenclature of osteology does not rest on any basis capable of conferring upon it a methodic form. Consequently, we find bones which derive their name from their shape, (example: the fibula); others from their resemblance to known objects (the tibia and vomer). Some owe it to their position (cétes, sides or ribs), or their uses (the axis and parietal bones). Several attempts have been made to submit the nomenclature of the bones to more precise and uniform rules, but the new designations proposed have not been sanctioned by custom. Situation. The situation of a bone should be viewed ia two ways: 1st, Relative to the median plane of the body ; 2nd, Relative to the other portions of the skeleton. A. Situation relative to the median plane of the body. The designation of median plane, or improperly median line, is given to an imaginary vertical plane, passing through the middle of the skeleton which it divides, from before to behind, into two equal portions. The bones may be situated on the median plane, in which case there is only one of each kind, and they are called single; they are also named symmetrical bones, because the median plane divides them into two equal lateral halves exactly alike. The bones disposed in a double and regular manner on the sides of the median plane bear, for this reason, the name of pairs; they are also called asymmetrical bones, because their form does not admit ‘of their being separated in any sense into two similar portions. On the contrary, a bone of this kind always offers the most perfect symmetry with its fellow on the opposite side. ? One lumbar vertebra less is found in the ass, and sometimes also in the mule. "? The os penis has not been included. * The sacrum is reckoned as a single bone, and the number of coccygeal vertebra: at an average of 12 for the Horse, 16 for the Ox, 14 for the Pig, and 15 for the Dog. * Theos hyoides comprises, and is reckoned as, a single bone. THE STUDY OF THE BONES. 11 B. Relative situation to the other parts of the skeleton.—To indicate the situation of a bone, considered from this point of view, is to make known the place it occupies in the region to which it belongs, and the connections it may have with adjoining regions. Thus the radius is situated in front of the ulna between the arm-bone and the carpus.’ Direction. This is absolute or relative. The direction of a bone may be vertical, horizontal, or oblique. Example: the scapula is placed in an oblique direc- tion from above to below, and from behind to before. Configuration of the Bones. Formu.—This is also absolute or relative. A. Absolute Form—tThe absolute form of a bone is that which it owes to the relations existing between its three dimensions—length, width, and thickness. a. A bone in which one of its dimensions much exceeds those of the other two is a long bone. Example:—the femur. All the long bones are hollowed out internally by an elongated space—the medullary cavity. Long bones belong exclusively to the limbs. In the animal economy, there are found bones which resemble them in their dimensions, but they have no medullary canal. Example:—the ribs. These differ essentially from the true long bones, and are sometimes distinguished from them by the appellation of elongated bones. b. A bone that offers two dimensions much more developed than the third, is a flat or wide bone. Example:—the parietal bone. The bones of this category, destitute of a medullary cavity, are met with in the head and the upper regions of the limbs. c¢. A bone which offers nearly the same development in all its dimensions, is called a short-bone. Example :— the astragalus. Destitute, like the preceding, of a medullary cavity, the short. bones are found in the spine and some regions of the limbs. B. Relative Form.—To make. known the relative form of a bone is to indicate the greater or less exact resemblance it may bear to geometrical figures, or to familiar objects.. Thus the scapula is a bone of a triangular form. _ Exrernan Pscuriariries or Bones.—These markedly attract the atten- tion, because they modify the general shape of bones, and singularly assist us in distinguishing one bone from another. These peculiarities, which are real distinctive features that permit their description to be precisely esta- blished, are always either eminences (processes) or depressions. E'minences.—The eminences that stand out in relief from the surfaces of. bones are divided into two different categories. One class concurs in the formation of the articulations which join the bones to each other; they are named articular eminences, in which, again, are distinguished diarthrodial and synarthrodial eminences, according as they belong to movable or immovable articulations. ‘The others, usually destined for the insertion of ligaments and muscles, are called non-articular, or eminences of insertion. (The term imprint is also used in anatomy, and signifies a collection of small rugged eminences which make the surface of the bone uneven and rough. There are muscular, tendinous, ligamentous, and aponeurotic im- prints, according as they give attachment to muscles, tendons, ligaments, or aponeuroses. ) ; : The synarthrodial eminences are always indentations more or less deep and finély cut. 12 GENERAL PRINCIPLES APPLICABLE TO The diarthrodial eminences are voluminous and smooth, and in a fresh state are covered with cartilage. They are named heads and condyles: heads, when they describe the segment of a sphere (head of the femur, head of the humerus); condyles, when they represent tne segment of an oval figure, cut parallel to its large axis (condyles of the femur.) ; The non-articular eminences receive various names. If they are volumi- nous and much detached from the bone, they are called processes or apophyses. Apophyses receive qualificatives derived from the analogies perceived between them and known objects. (Examples :—the styloid, clinoid, coronoid and coracoid processes.) The appellations of protuberances and tuberosities are given to non-articular eminences when they are large and round, and but slightly prominent. Lastly, they are named lines, crests, and ridges, when they are narrow and very long. ; Cavities. —The cavities of bones have also been divided into articular and non-articular cavities. The first correspond to the eminences of the same name in the bony joints. They take the designation of cotyloid cavities when they are deeply excavated, like a basin or the cup of an acorn (the glenoid cavity of the scapula, and the cotyloid cavity of the coxa). The non-articular cavities serve either for ligamentous or muscular implantation, or for the passage of vessels, nerves, tendons, etc. They are termed channels or furrows, when they are wide, deep, and smooth; grooves, when they are long, narrow, and even at the bottom; Jissures, when they are narrow and rough. Digital impressions ts the name given to those excavations in bones which look as if produced by the pressure of the finger. The fosse, sinuses, cells, and notches are also non- articular cavities of bones. The sinuses and cells are formed by open spaces in the interior of bones; notches, by cavities excavated on their margins. When a cavity passes quite through a bone it is termed a foramen. If this foramen offers a certain length, it is then designated a conduit or canal. Fissures are long, narrow foramina; hiatus is the term applied to wide openings with irregular outlines. Recions or THE Bonzs.—When it is desired to describe the eminences and external cavities of a bone, it is essential not to notice them, as it were, by chance—passing indifferently from one to another. In order to avoid the difficulties which would result from the application of such an irrational system, it is convenient to divide the bone to be described into several regions, in which are examined, one after another, all the external peculiari- ‘ties that may offer. The following is the course to pursue in order to establish the regions of a long, a flat, and a short bone. (a) A long bone is always divided into three parts: a body and two extremities. The body, middle part, or diaphysis, is the narrowest portion of the bone. It represents a geometrical solid, approaching more or less the figure of a very elongated prism. In a long bone, therefore, it is necessary ee study as many faces, angles, or borders, as the prism it represents may offer. With regard to the extremities, or epiphyses, these are more or less con- siderable enlargements, showing articular surfaces, as well as surfaces intended for muscular or ligamentous insertion. ( b) A flat bone must necessarily have two faces, as well as borders and angles, THE STUDY OF THE BONES, 13 . (c) A short bone offers for description a variable number of faces, and plane or salient angles, which are often neglected because of their trifling importance. Internal Conformation of Bones. Sections made in various directions through the substance of bones show that their internal conformation varies, according as they belong to the category of long, flat, or short bones. The diaphysis of long bones is hollowed out into a large fusiform cavity; this is the medullary canal. This canal is absent in the flat and short bones. Its walls are formed by a very dense bony tissue, whose pores are scarcely visible to the naked eye, and which is called the compact substance. The extremities of long bones are surrounded by a thin layer of compact substance, while the remainder of their mass is constituted by the spongy substance—bony tissue channeled into cells, or very large areole, which freely communicate with each other. (Reticulated bony tissue is but another form of spongy substance, the only difference between the two consisting in the cells or meshes of the first being formed of intercrossed osseous fibres, while those of the second are formed of lamelle.) The medullary canal, and areole of the spongy tissue, are filled by a cellulo-fatty substance, the marrow (or medulla), The flat bones are constituted by a layer of spongy tissue placed between two laminz of compact substance. In the flat bones of the cranium, the two layers of compact tissue are termed the vitreous tables, while the cells of the spongy tissue are designated diploé. In certain points of their extent, the spongy substance disappears, and then the bone is found to be composed of a single lamina of compact tissue. The short bones have a nucleus of spongy substance, enveloped in a layer, more or less thick, of compact tissue. ~ The compact substance of the bones being very resisting, is found in all those situations which have to sustain violent efforts. The spongy substance is very light and bulky, and is met with in the widened portions of the bones, to which it affords increased size without adding sensibly to their weight, Structure of Bones. Bones are formed of a proper tissue, covered externally by a particular Fig, 6. membrane, the periosteum, and occupied internally by the medulla, vessels, and nerves. Proper tissue.—The texture of the proper tissue of bones varies slightly in the compact and spongy substance. The compact tissue is composed of a funda- mental substance, which is amorphous, or slightly granular, white, and more or less opaque, accord- ing to the thickness it offers. This fundamental substance is penetrated by an infinite number of vascular canaliculi, known as the Haversian canals. These canals, which measure from 1-2500th to 1-200th of an inch in C ry ted [ \ | diameter, are parallel to each other and to the a municate by transverse branches. The most | oan section a ny superficial open on the surface of the bone, be- “showing the network of larger axis of the bone; they frequently com- jf} ‘ Nile Wt \ neath the periosteum, and the deepest into the Haversian canals. 14 GENERAL PRINCIPLES APPLICABLE TO medullary canal; while a certain number terminate in the areole of the spongy substance. : 2 tituted by several concentric lamelle The walls.of these canals are cons " eel owt sae alee Fig. 7. the body of these are lodged the essential elements of the bony tissue, or osteoplasts (corpuscles or lacune). These are minute cavi- ties lined by a cellular membrane, and furnished, at their: circum- ference, with a great number of canaliculated prolongations, which . communicate with the adjacent osteoplasts,-or with the Haversian canals, In a thin dried section of bone, the osteoplasts appear black by transmitted light, and = white and brilliant by direct light; MINUTE STRUCTURE OF BONE, as shown ina thin t¢hig appearance has led some ob- Halil aaa a | to the direction of the servers to suppose that they Scans 1, A Haversian canal surrounded by its concentric formed of small masses of calca- lamelle; the lacune are seen between the la~- reous matter. It is now well mellz, but the radiating tubuli are omitted; known. that they are minute 2, dbid, with its concentric lamina, lacune, and ramifying cavities, lodging a cell radiating tubuli; 3, The area of one of the . : Boa eanals; 4, 4, Intervening lamella, and between impregnated with liquid. them, at the upper part, several very long In the spongy texture no lacunz with their tubuli, Haversian canals can be seen, the osteoplasts are irregularly Fig. 8. disposed in the thickness of the fundamental substance, which con- stitutes the septa of the areole of this tissue. As a rule, the proper tissue of the bones is composed of a frame- work of organic matter which has gelatine for its base, and in which are deposited the calcareous phos- phates and carbonates, which give to this tissue its characteristic hardness. This is easily rendered evident by immersing any bone in dilute nitric or hydrochloric acid ; acids dissolve the calcareous salts, but do not act upon the organic framework. So it is that, after some days’ maceration, the bone becomes flexible, like cartilage, and loses part of its weight, although it preserves its volume. The counterpart of this experiment may be made by submitting it to the action of fire. It is then rendered quite friable, because its organic skeleton has been destroyed without the earthy salts it contained being affected. Periosteum.— This is a very vascular and nervous fibrous membrane that covers the entire bone, with the exception of the articular surfaces. Its thickness and adherence are not the same everywhere. By its inner face it corresponds to the surface of the bone; by its external face, it is confounded with the insertion of the tendons and ligaments, or with the surrounding connective tissne, LACUN#E, OR OSTEOPLASTS OF OSSEOUS SUBSTANCE, magnified 500 diameters. a, Central cavity; }, Its ramifications. THE STUDY OF THE BONES. 15 The periosteum may be resolved into two layers, though these are not very distinct. The superficial layer is essentially fibrous, and is formed by a mixture of connective and elastic fibres and plasmatic cells. The deep layer also contains a loose connective tissue, but more especially elastic fibres, and more or less voluminous spherical or fusiform cells, This is called the osteogenous layer. Medulla.—The medulla, or marrow, is a pulpy, fatty substance, which fills the medullary canal and the areole of the spongy tissue of the bones. Somewhat consistent, and of a rose tint in the bones of the young animal, the marrow becomes diftluent and yellow in the bones of those advanced in age. In the first instance, it only contains traces of fat; while in the second it has 96 per cent. of this substance. The medulla of bones is composed of: Ist, Some trabecule of delicate connective tissue, which serves to support the vessels and nerves; 2nd, Fat either free or inclosed in vesicles; 8rd, Particular cells, named by M. Robin medullo-cells and myeloplaces. The medullo cells, abundant in the red or foetal marrow, are small cells with a spherical nucleus; while the myeloplaxes are large, flattened, or polyhedral elements of an irregular outline, containing a great number of nuclei. Rare in the yellow marrow, they are more particularly found adhering to the walls of the medullary canal, or the alveoli of the spongy tissue. Blood-vessels.—The arteries of bones belong to three orders; a distinction founded on their volume and the extent of their distribution. The arteries of the first order penetrate to the interior of the medullary canal of long bones by a particular orifice, the nutritious foramen. They soon divide into two branches, which break up into a network that lines the walls of the canal and enters the tissue of the medulla. This network communicates with the arteries of the second order, which are destined to the spongy tissue of the extremities of the long bones, penetrating them by the numerous nutritious foramina that surround the epiphyses. Lastly, the arteries of the third order are branches of the periostic network which enter the superficial Haversian canals. These canals which open in this manner on the surface of the bones may be considered, strictly speaking, as a third category of nutritious conduits. In the flat and short bones there are no arteries of the first order. . Veins accompany the arteries, and are always more voluminous than these; they frequently make their exit by special and very large openings at those points where the spongy tissue is abundant. The veins of bones sometimes exhibit saccular dilatations on their course. Certain veins in the cranial bones have their parietes entirely composed of osseous tissue. Lymphatic vessels.—The existence of these in the interior of bones cannot be affirmed. ee Nerves.—These belong to the cerebro-spinal and ganglionic system of nerves ; the latter are always vaso-motory nerves. Almost constantly a somewhat voluminous nerve enters the medullary canal by passing through the nutritious foramen, and is distributed to the medulla. The compact tissue receives few nervous filaments; while, on the contrary, the spongy tissue at the extremities of the long bones, as well as the short bones, obtains an abundant supply. Certain short bones, such as the vertebra, are especially remarkable for the numerous nerves they receive, 16 GENERAL PRINCIPLES. APPLICABLE TO DEVELOPMENT OF BONES. Bones, before arriving at the state in which they present themselves in the adult animal, pass through several successive phases, whose study consti- tutes what is termed osteogeny. In the embryo, at a very early period, the bones are composed of a mucous material analogous to that which enters into the composition of all the other organs; this matter is constituted by a mass of what are called embryonic cells, Ata later period they are impregnated with gelatine, and nearly all become harder, white, and elastic, passing into the cartilaginous state. Exception must be made, however, to the lateral and anterior parietes of the cranium and the face, the bones of which are at first fibrous but never cartilaginous. The cartilaginous bones show a fundamental amorphous substance, in which are disseminated spherical cells containing one or more nuclei. This condition is transitory; the cartilaginous tissue soon submits to modifications which result in conferring on the pieces that it composes the hardness and structure of perfect osseous tissue. These modifications constitute the process of ossification. ‘There are several portions of the skeleton which do not undergo this osseous transformation, and which most frequently remain in the cartilaginous condition during the entire life of the animal. These permanent cartilages are met with at those points where the bony skeleton must preserve a certain degree of flexibility, and on the articular surfaces. During the process of ossification, the cartilages become vascular, are impregnated with calcareous salts, and excavated with Haversian canaliculi and medullary cavities. The saline molecules are deposited in the amorphous substance, which grows more hard and opaque ; at the same time the cartilaginous cells become the point of departure of a new embryonic proliferation, from which results the neoplasts. Ossification begins at the same time in several parts of the skeleton, and in each of the bones in particular; though it does not appear over the whole extent of the latter at once; on the contrary, in certain determinate points of the cartilaginous mass, bony tissue can be perceived developing itself and extending gradually until it finishes by completely invading it. These points are called centres of ossification. These centres are primary or complementary ; the latter are in some way added to the bone, and form, wholly or in part, certain processes. Although these centres of ossification enlarge from day to day, yet for a somewhat long period they remain completely independent of one another, and are only connected by cartilaginous tissue. The term epiphyses is given to the osseous centres which are placed at the extremities of the principal centre. When the skeleton is completely developed, the various centres of ossification are fused into each other, and then there are no longer epiphyses ; this fusion always takes place at an almost determinate epoch. It has been remarked that, of two epiphyses, it is con- stantly the one near which the nutritious foramen is directed that is first united to the body of the bone. Growth.—Bones grow in width and thickness by the apposition of new elements. In the long bones, the growth in length takes place by the ossification of the cartilage uniting the epiphyses to the body of the bone. Consequently, elongation should cease as soon as the epiphyses are incor- porated with the diaphysis. With regard to the long bones of the limbs, Duhamel, Flourens, and particularly MM. Ollier and Humphry, have remarked that, in the thoracic limb, the extremity furthest removed from THE STUDY OF THE BONES. WwW the humero-radial articulation grows fastest; while in the abdominal limb. the extremity most distant from the femoro-tibial articulation grows the least, ‘Concerning the growth of the bones in thickness, this occurs by the ossifi- cation of the deep layer of the periosteum called the osteogenetic layer. The experiments of the above-named authors have irrefutably demonstrated this fact. ‘The formation of bony tissue in the deep layer of the periosteum is very active during the youth of animals; but it soon slackens, and in advanced age ceases completely. In the first period of life, in proportion as the new layers are added to the surface of the bone, the old layers, those nearest the medullary canal, disappear by resorption. Later, the process of resorption exceeds that of formation, which is, in old age, completely annihilated. It has also been observed that the formation of a certain quantity of the osseous elements takes place on the inner face of the medullary canal, at the expense of the medullary tissue. In the flat bones, the primitive centre of ossification is developed nearly in the middle, and the calcareous salts are afterwards deposited in radiating lines from this spot towards the periphery. These bones are augmented in thickness by the formation of subperiostic layers, and by the development of the spongy tissue between their two compact lamine; they increase in width by the ossification of what are termed the marginal epiphyses. The short bones grow from the periosteum and the epiphysery cartilages, when they possess complementary centres. Nutrition.—The experiments which consisted in feeding young animals with madder, and afterwards examining their osseous system, have for a long period demonstrated the nutrition of bones. When bones cease to grow, their nutri- tion becomes less active; but it is evident that it does go on, in order to maintain the organic matter of the osseous tissue in a proper con~ dition. (Professor Owen has explicitly and concisely stated the development of bone to occur as fol- lows :—-“ The primitive basis, or ‘ blastema’ of bone is a transparent glairy matter containing numerous minute corpuscles. It progressively acquires increased firmness ; sometimes assuming a membranous or ligamentous state, usually a gristly consistence, before its conversion into bone. The change into cartilage is noted by the appearance of minute nucleated cells, which increase in number and size, and are aggregated in rows, with intercellular tracts, where the ossification is about to begin, as in fig. 9. Gaerne An eR) BERR OR These rows, in the cartilaginous basis of “ ossipicarton, showing at its long bones, are vertical to its ends; in that of lower portions the clusters flat bones they are vertical to the margin. The of ge oe ae eal cells furthest from the seat of ossification are ech of which is inclosed in a flattened and in close contact; nearest that seat cbstance. they become enlarged and separated. ; ; ; The first appearance of bone is that of minute granules in the inter- columnar and intercellular tissue. Canals are next formed in the bone by 18 THE BONES absorption, which ultimately receive bloodvessels, and become the ‘ — canals’ The immediate nutrition of bone is provided for by the production of minute ‘plasmatic canals’ from the vascular ones. When uhese canals become dilated, so as to offer definite forms, they are termed ‘ lacune ae ‘bone-cells, and to some extent characterise, by their shape and size, the osseous tissue of the respective vertebrate classes. In the concentric lamine surrounding the vascular canal, the bone-cells or osteoplasts are arranged concentrically, between the lamina, with the long axis in the direction of the circular line of the plate. Most of the plasmatic tubes con- tinued from the bone-cells pierce the plates at right angles in their course to the vascular canal, with which they communicate; and they form the essential vehicle of the material for future growth. Extension of parts, however, is not the sole process which takes place in the growth of bone; to adapt it to its destined offices, changes are wrought in it by the removal of parts previously formed. In marine creatures, the bones usually remain solid; but in the active land quadrupeds, the shaft of the long bones is hollow, the first-formed osseous substance being absorbed, as new bone is being deposited without. The strength and lightness of the limb-bones are thus increased after the well-known principle of the hollow column. The bones of birds present this quality in the highest degree, particularly those of powerful flight. In these the medullary cavity of beasts is transformed into a capacious cavity containing rarified air instead of marrow. In the mam- malian class, the air-cells of bone are confined to the head, and are filled from the cavities of the nose or ear, not from the lungs, as in birds. Such cells are called ‘frontal sinuses, ‘antrum,’ ‘sphenoidal, and ‘ ethmoidal.’ The frontal sinuses extend backward over the top of the skull in the rumi- nant and some other quadrupeds, and penetrate the cores of the horns in oxen, sheep, and certain antelopes. The most remarkable development of cranial air-cells is presented by the elephant, the intellectual physiognomy of this large quadruped being caused, as in the owl, not by the actual capacity of the brain-case, but by the vast extent of the pneumatic cellular structure between the outer and inner plates of the skull-wall. All these varied changes in the osseous tissue, from mere cancelli to large medullary or pneumatic cavities, are the result of secondary changes by absorption, and not of the primitive constitution of bones, which were at first solid.”) CHAPTER II. THE BONES OF MAMMALIA IN PARTICULAR. Arvictz I.—Verreprat Conumy. Tue vertebral column, or spine, is a solid and flexible stalk situated in the middle and upper part of the trunk, of which it forms the essential portion. It protects the spinal cord and sustains the thorax, as well as the principal organs of the circulation, respiration, and digestion. Articulated anteriorly with the head, and terminating in a point at its posterior extremity, this piece is formed by a Somewhat considerable assemblage of short single tuberous bones, to which has been given the name of vertebrae, These’ THE VERTEBRAL COLUMN. 19” bones, though all constructed on an uniform type, yet do not offer the same configuration throughout the whole rachidean stalk. The differences they present into this respect, have allowed of their being formed into five prin- cipal groups; whence the division of the vertebral column in five regions, which are, enumerating them from before to behind: 1, Cervical region; 2, Dorsal region ; 3, Lumbar region ; 4, Sacral region ; 5, Coccygeal region. The first comprises seven vertebre, which serve as a base for the animal's neck; the second has eighteen, against which the ribs are placed ; the third has only six, which correspond to the loins; in the fourth there are five, constantly solidified into one mass in the adult, to constitute a single bone— the sacrum ; while the fifth possesses a variable number of small degenerate vertebrx, gradually decreasing in size to form the tail. The pieces consti- tuting the first three regions are called true vertebree; those of the last two are designated false vertebre. : The characters belonging to all these vertenre will be first studied ; then a particular description of the vertebre of each region will be given; and, finally, an examination will be made of the spine as a whole. CHARACTERS COMMON TO ALL THE VERTEBRE. Each of these small bones is pierced from before to behind by a wide ELEMENTS OF A VERTEBRA: AFTER OWEN. 2 al typical vertebra; B, Actual thoracic vertebra of a bird; c, Centrum (or 5: me eins off, d, d, the ‘diapophyses, and p, P, the parapophyses Cag nealn eu articular processes); the neural arch, inclosing the spinal cord, is forme i n, n, the neurapophyses (/aminw), and 1, », the neural spine (spinous process); the heemal arch, inclosing the great centres of the circulation, is formed by A, h, the hamapophyses (costal cartilages) , and fh, s, the ner lee Coat ay From both the neurapophyses and heemapophyses may be given o a e aygapop yses, z, 2. The lateral arches, which may inclose the vertebral arteries, 0, ® are completed by the pleurapophyses (ribs), pl. 5 these in Bare bent downwards, so as to form part of the hemal arch, and give off the diverging appendages, u, a. s a ‘ ' iy i he spinal foramen ; whence results, for the entire spine, a pea eae its whole length, and which lodges a very important 20 THE BONES. portion of the nervous centres—the spinal marrow. This canal, which traverses the vertebra’ from one end to the other, transforms it into a veritable ring in which we recognise, for facility of description, two parts— the one inferior, the other superior. ‘The first, or body; is very thick, and forms the base of the vertebra; the second, which is thin, has been de- signated spinous or spinal, from one of the peculiarities it, presents, or annular, because it circumscribes the major portion of the spinal foramen. This division is not altogether an arbitrary one, for the body and the annular por- tion constitute, in the foetus, two distinct pieces, which do not become united for a long time after birth. ; ; Bopy.—The shape of the body of a vertebra is that of a prism with four faces, of which two only—the superior and inferior—are free, and can be studied in the adult; the two lateral faces being united and confounded with the annular portion. This prism also presents two extremities—an anterior and posterior. ; Faces. —The superior face, limited in extent, forms part of the spinal foramen, constituting its floor. It exhibits: 1, On the median line, two roughened, prominent surfaces, representing two triangles, whose summits are opposed; 2, On the sides, two depressed smooth surfaces, perforated by one or more openings that lead to the interior of the bone. The inferior face is divided into two lateral portions by a median crest. Extremities.—The anterior has a prominent convex head, more or less detached. The posterior offers a cavity for the reception of the head of the next vertebra.. These two planes, the one convex, the other concave, do not come into immediate contact; an elastic, flexible fibro-cartilage, firmly attached to each, being interposed between them. Annutar Portion.—This is formed by an osseous plate that curves sud- denly downwards, in the shape of an arch, the two extremities of which approach each other, inclose the body, and become united to it. It offers for study: 1, An internal and an external surface; 2, An anterior and a posterior border. Surfaces.—The internal surface, concave and smooth, forms, with the superior face of the body, the spinal foramen. The ewternal, convex and irregular, presents: 1, A single prominence, raised in the middle of the superior portion, and named the spinous process ; 2, The transverse processes are a double pair of eminences, one on each side, and projected transversely outwards. Borders,—The anterior border has two articular facets looking upwards: these are the anterior articular processes, right and left. In each is a notch which, when placed in opposition to a similar excavation in the preceding vertebra, forms the intervertebral foramen. The posterior border presents the same peculiarities, with this difference, that the articular faces of the pos- terior articular processes are inclined downwards, to correspond with the anterior facets of the succeeding vertebra. Structure of the vertebre.—The compact substance, which is abundant in the spinous portion, forms, in the body, an extremely thin layer, inclosing \ a voluminous nucleus of spongy tissue. The latter is traversed by numerous venous canals, which open on the surface of the bone. Development.—tIt has been already shown that the body and spinous portion of a vertebra constitute, in young animals, two distinct pieces. Each was primarily formed from two lateral centres, which met on the median line. In the body, the fusion of these centres is so prompt, that it is generally believed, perhaps justly, that the development of this part of the vertebra THE VERTEBRAL COLUMN. 21 proceeds from a single centre of ossification. The union of the two centres in the annular portion, usually designated the vertebral lamin, is slower It commences in the most anterior vertebre, and is latest in the sacral mee coccygeal regions. To the two principal pieces of the vertebra in process of ossification, is added, at a subsequent period, complementary points of ossifi- cation, five or six in number: one or two for the spinous process, one for the summit of each transverse process, another for the head, and the last for the posterior cavity of the body. CHARACTERS PROPER TO THE VERTEBRE OF EAOH REGION. A casual inspection of a vertebra might suffice, strictly speaking, to dis- tinguish the region of the spine to which it belonged. For instance, a cervical vertebra is recognised by its volume, the absence of a spinous process, and the foramen which traverses the base of its transverse processes. The dorsal vertebra is conspicuous by its tubercular transverse processes, and by being furnished, outwardly, with an articular surface, as well as by the depression on its body destined to receive the heads of the ribs. The lumbar vertebra has its long flattened transverse processes; while the coccygeal vertebra offers rudimentary lamines and processes. There is no necessity for noticing the sacrum, whose five pieces form one bone: a feature _ which markedly distinguishes it from the other regions of the vertebral -column. But these few distinctive characteristics do not satisfy the require- ‘ments of descriptive anatomy; so that it is necessary to undertake a more extensive study of each of these regions. 1. Cervical Vertebre., GervzeraL Coaracters.—These vertebre, the longest and thickest in the spine, present generally a cubic form. They are usually distinguished from the vertebre of the other regions by the following characters :—The inferior spine of the body is strongly marked, especially behind, where it terminates in a small tubercle. The head is well detached from the re- mainder of the bone, and deseribes a very short curve. The posterior cavity, wide and deep, represents a veritable cotyloid depression, which is too large to fit the head exactly; the intermediate fibro-cartilage on these two surfaces is also of a great thickness. The spinous process forms a simple roughened, and but slightly prominent, ridge. The transverse processes, very developed, are elongated in an antero-posterior direction, and inclined down- wards. ‘In this region they are designated the trachelian processes, because of their relations with the trachea; a foramen that traverses them from before to behind at their base has been, for the same reason, named the trachelian foramen (vertebral foramen). The articular processes, large and prominent, are inclined downwards and inwards. The notches are wide and deep. Apectera Cuaracrens.—The seven cervical vertebra are reckoned from before to behind, and receive numerical names indicating their place in the region. ‘ O riet,—The first vertebra of the neck, which has been named the atlas, deserves a very careful description. At first sight there is recognised the 1 So named from thé mythological personage who was supposed to support the earth, as the first vertebra (human) supports the head. (For this bone in the domesticated animals the name is not appropriate.) 5 Neeme 99 af THE BONES. great development of its ‘transversal diameter, the considerable dimensions of the spinal foramen, and the thinness of its body. The intra-rachidian- face of the latter is divided into two portions by a transverse ridge: one anterior, furnished with ligamentous imprints, exhibits, laterally, two deep excavations, which lodge the venous sinuses; the other, posterior, is smooth and concave from side to side, and forms an articular surface into which is received the odontoid process of the axis; this surface resembles the ATLAS 5 INFERIOR SURFACE. 1, Articular processes for condyles of the occipital bone; 2, ibidem; 3, Vertebral or antero-internal fora- men; 4, Posterior, or cervical fora- ‘men; 5, Transverse process; 6, Tubercle representing the inferior spinous process; 7, Superior arch, forming the roof of the spinal fora- men. Fig. 12. @ A CERVICAL VERTEBRA, 1, Superior spinous process; 2, An- terior articular processes; 3, Pos- terior articular processes; 5, An- terior convex face of body, 6, 7, Transverse processes, with their .tubercles or rudimentary ribs; 8, Inferior crest, or spine; 9, Concave posterior face. from six centres of ossification becomes a solid piece, and two for complementary centres, each undulated facets, and the lip of Second.—This is named the axis cervical vertebrae ; those which succeed it augment in thickness. cotyloid cavity. The inferior spine of the body appears as a large tubercle. The head is absent, and is replaced by two concave facets. The anterior articular processes have their gliding surfaces looking downwards; they are joined to the two preceding facets to constitute two large diarthrodial cavities, which correspond to the occipital condyles. There is no spinous process, but a rough- ened surface instead. The transverse pro- cesses are large, flattened above and below, incline forwards and downwards, and are provided with a thick rugged lip. Pos- teriorly, quite at their base, and on each side of the spinal foramen, they show two large vertical facets which represent the posterior articular processes; these facets are uneven, are confounded with the articular cavity of the upper face of the body, and correspond to the two analogous facets of the axis. Each transverse process is pierced at its base by two foramina, which traverse it from below upwards. The posterior repre- sents the vertebral foramen of the other ver- tebree ; while the anterior is continued to the external surface of the process by a wide, deep, but very short channel, running from without to within, and joins a third fora- men, which enters the spinal canal. These last two openings, with the demi-canal which unites them, replace the anterior notch; the posterior is altogether absent. Lastly, an inflected venous canal, whose position varies, and whose presence is not constant, crosses the lamine of the atlas, and opens, on one side, into the spinal canal, and on the other, beneath the trans- verse process. The atlas contains much compact tissue, and is generally developed two for the body, which at an early period the annular part; the other two are of which forms one of the two posterior the corresponding transverse process. (or dentata). It is the longest of all the gradually diminish in length and The body of the axis has not any head anteriorly, THE VERTEBRAL COLUMN, .- 23 but conical process termed the odontoid, which is flattened above and below, concave and rough from one side to the other on its superior face ; convex in the same direction, and perfectly smooth on its inferior face. The latter represents an articular half-hinge, around which glides the concave arti- cular surface on the superior face of the body of the atlas. The anterior articular processes are carried to the é base and to each side of the odon- 1/ toidian pivot, in the shape of two un- dulated facets, which are confounded with the gliding surface of the latter, whose destination has been already noted. The spinous process, very powerful and elongated antero-pos- teriorly, is divided behind into two) gyn AXIS, OR DENTATA} LATERAL VIEW, roughened lips. The transverse PTO- 1, Superior spinous process; 2, Odontoid pro- cesses are slightly developed, and ter- cess; 3, Intervertebral foramen, or hole of minate posteriorly inasingle tubercle, conjugation; 4, Body; 5, Inferior spinous directed backwards. The anterior Process; 8,7, Inferior and superior articu- lating processes. notches are very deep, and are most frequently converted into foramina. This vertebra, although voluminous, is light, in consequence of its containing much spongy substance. In the young animal, the odontoid process and the articular surfaces on each side, constitute two centres, distinct from each other and from the body of the vertebra. After the axis, the cervical vertebre diminish in length and increase in thickness ; while the obliquity of their articular processes becomes the more pronounced the more distant they are from that vertebra. Third, fourth, and fifth—Each of these has, at its transverse processes, two prolongations, one anterior, the other posterior. The inferior face of their bodies exhibits a median spine terminated posteriorly by a tubercle, which gradnally increases in volume from the third to the fifth vertebra. The third presents, between its anterior and posterior articular processes an almost complete gap; if its anterior extremity be placed on a horizontal plane, it will touch that plane by its articular and transverse processes and its head. In the fourth, the articular processes are united by a thin, sharp osseous plate, notched only in front. Laid on a horizontal plane, the head remains some distance from it. The fifth is known by the continuous, thick, and rugged lamina which unites the articular processes, and by the tubercle of the inferior spine on the body, which is in shape like the heart on a playing-card. : . Sixth.—This is distinguished by the slight prominence of the spinous process, but particularly by the almost total disappearance of the inferior spine, and the presence of a third prolongation, very strong and inclining downwards at its transverse process, a circumstance to which this vertebra owes its designation of tricuspid. ; ; Seventh.—This has received the name of prominens, because its spinous process, terminating in a point, is more distinct than in the preceding vertebrae, the axis excepted. It exhibits, besides: deep imprints, which replace the inferior spine, a concave demi-facet on each side of the posterior cavity for the articulation of the head of the first rib; a particular disposition of its transverse processes, which are unituberculous ; the complete absence of the vertebral foramen; and, lastly, the depth and width of its notches, 24 THE BONES. The spinal foramen, which has already assumed a somewhat considerable diameter in the sixth cervical vertebra, is still larger in the seventh." 2.—Dorsal Vertebre. GuryzraL Caaracters.—In the dorsal vertebra the body is very short, and in front has a large slightly projecting head; behind, it has a shallow cavity. laterally, these vertebre present, at the base of the transverse processes, four concave articular facets, the two anterior of which are situated near the head, while the posterior two are hollowed out of the Border of the articular cavity of the body. Each of these facets is joined to Fig. 14. an analogous facet on the neighbouring ver- 5 tebra to form a small excavation, into which is received the head of the corresponding rib. The spinous process is very high, is compressed on both sides, inclines backwards, and its summit is terminated by a tubercle. The transverse processes are unitubercular, and directed obliquely cutwards and up- wards; on their external aspect they have a diarthrodial plane facet which corresponds to the tuberosity of the rib, The articular processes are narrow, and constitute simple unrelieved facets cut on the base of the spinous process. The posterior notches are deep, and sometimes converted into foramina. Spzcirrc CHaracters.——None of the eighteen dorsal vertebre differ much from the type just described; and it is difficult to establish special characters for each. TYPE OF A DORSAL VERTEBRA 3 é . . THe FOURTH: ’ Tt is, nevertheless, possible to assign to a 1, Body; 2,2, Articular facets for the dorsal vertebra, approximately, the rank it head of rib; 3, Articular facet for should occupy, in accepting the following tuberosity of the rib; 4, Articular facts as a guide:—1. The vertical diameter processes; 5, Spinal foramen; 6, . é Tastone ese on epinouspimecsas of the vertebral bodies augments progres 7, Posterior articular face of body; Sively from before to behind. Their lateral 8, 8, Transverse processes; 9, diameter, which determines that of the spinal Superior spinous process; 10, An- canal, becomes, on the contrary, less from the ual ertieullnearol venye first to the tenth vertebra; after which it assumes increasing proportions to the last one. The articular surfaces, which serve for the mutual contact of head and cavity, become larger and shallower in proportion as the vertebre are more posterior. The inferior spine on the body is very salient and tuberculous in the two first vertebrae, very acute in the third and fourth; it disappears in the sixth and ninth, to re-appear and become more marked from the tenth to the last. 2. The intervertebral cavities, intended for the reception of the heads of the ribs, diminish in depth and extent from the first to the last. 3. The longest spinous process belongs to the third, fourth, and fifth vertebre; those which follow gradually decrease to the eighteenth. Their width diminishes from the second to the eighth; it afterwards increases in a progressive manner in the succeeding vertebrae; ' M. Goubaux has sometimes met with asymmetrical cervical vertebrae ; certain vertebre, tricuspid on one side, are only bicuspid or unicuspid on the opposite side. THE VERTEBRAL COLUMN. 25 from the second to the tenth vertebra, the summit of the spinous process is large and tuberculous; in the last seven it is flattened laterally. Their obliquity is less marked as they proceed backwards; in the sixteenth and seventeenth vertebre, the spinous process is nearly vertical; it inclines slightly forward in the eighteenth. Those of the tenth, eleventh, and twelfth vertebre are slightly curved like an S. 4. The articular processes, from the first to the tenth vertebra, gradually contract and approach the median line; in the succeeding vertebre they, on the contrary, increase, and become concave and wider apart from those of the opposite side. 5. The volume of the transverse processes and the size of their diarthrodial facets diminish from before to behind. In the three first vertebre this facet is concave; in the first nine the articular facet looks outwards and backwards, while the facet on the body looks forwards; in the last the two facets are directed forwards. These two facets are generally confounded in the seventeenth and eighteenth vertebrae. The first dorsal vertebra much resembles the prominens; it is distinguished from it, however, by the presence of four diarthrodial facets on its extremities. It also differs from the other vertebrae by the shortness of its spinous process, which terminates in a point; by the size and prominence of its articular processes ; and by the depth of its notches. The last vertebra never has facets on the contour of its posterior cavity. 8. Lumbar Vertebre. GeveraL Cuaracters.—A little longer and wider than the dorsal vertebra, which they resemble in the arrangement of their bodies, these vertebrz are characterised: 1, By their short, thin, and wide spinous processes, which are slightly inclined forwards, and are provided at their summits with a scabrous tubercle; 2, By their largely developed transverse processes, flattened above and below, and directed horizontally outwards;? 8, By the salient anterior articular processes, hollowed out on each side, and provided externally with a tubercle for insertion; 4, By their equally prominent posterior articular processes, rounded in the form of a half-hinge. Sprciric CHaractEers.—The characteristics which may serve to distinguish these vertebre from one another are derived from the body, and the spinous and tranverse processes. 1. From the first to the last there is a progressive diminution in the vertical diameter of the bodies, and an increase in their transverse diameter. The inferior spine on the body becomes shorter and wider from the first to the last vertebra; in the six vertebre it resembles an elongated triangle whose summit is directed forwards. 2. The spinous processes decrease in width from before to behind, and their anterior border becomes more and more concave; their summits are thickened and tuberculous in the three first, and thin and sloping forward in the three last. 8. The transverse processes are longer in the middle vertebra than in those placed before and behind. The processes in the first and ' In well-formed horses, it is not uncommon to find nineteen dorsal vertebre, with an equal number of ribs; though in these instances there are most frequently only five lumbar vertebre. Husson and Goubaux have sometimes met with nineteen, and the normal number in the other regions. Sometimes there are only seventeen dorsal vertebree. 2 It has been correctly stated that these processes are the representatives of rudi- mentary ribs which have become united to the vertebre. Therefore it is that they are frequently designated costiform processes. 26 THE BONES. second vertebre incline slightly backward; in the third they are more up- right ; and in the supieeiiiste an are directed a little forward. In the last Fig. 15. UPPER SURFACE OF LUMBAR VERTEBR.E. 1, Summit of spinous process, 2, 2, Anterior articular processes; 3, 3, Posterior articu- lar processes, 4, 4, Transverse processes. Fig. 16, LUMBAR VERTEBRA; FRONT VIEW. 1, Body; 2, Its articular face ; 3, Superior spinous process; 4, Spinal foramen; 5, Anterior articular processes; 6, 6, Transverse, or costiform pro- cesses, 7, Posterior articular process. two they are remarkable for their thickness ; in the fifth an oval-shaped articular facet is observed on their posterior border; in the sixth, two are present—one in front, correspond- ing to the preceding, and one behind, slightly concave, meeting a similar facet on the sacrum. The fourth and fifth vertebrae very often correspond, at their transverse processes, by means of analogous facets.’ In the Ass, and sometimes in the Mule, only five lumiar vertebre are found. According to M. Sanson, this is the natural number in the Arab Horse.” 4, Sacrum. The sacrum results, as already stated, from the consolidation of five vertebre. This single bone articulates, in front, with the last lumbar vertebra; behind, with the first coccygeal bone, and on the sides with the ossa innominata. It is triangular, flattened above and below, and from before to behind describes a slight curve up- wards. It offers for study a superior and an inferior face, two borders, a base, a summit, and a central canal, the exten sion of the spinal canal. Faces—The superior face presents, on its middle, the spi- nous processes of the sacral vertebrae, which together con- stitute what is called the sacral or supersacral spine. These processes are united at their base only, and remain isolated for the remainder of their ex- tent; they all incline backwards ' We possess the skeleton of a horse which has seven lumbar vertebrae, with the normal complement in the other regions, has all its characters, region. * (This statement is scarcely correct. which has six.) The seventh is no doubt the first sacral, as it The fifth sacral vertebra is evidently derived from the coccygeal i i M. Sanson_has established the fuct that there is in reality no Arab horse; and asserts that the specific t is very probably of African origin, and that these vertebr offer individual characteristics different from those obs ype with five lumbar vertebra, ve, independently of their number, erved in the vertebra of the type THE VERTEBRAL COLUMN. 27 and terminate, with the exception of the first, by a tuberous summit, which is often bifid; their length diminishes from the second to the fifth bone. On each side of the sacral spine exists a groove, at the bottom Fig. 17. of which are four openings—the supersacral foramina. These orifices open into the spinal canal, and communicate with four analogous, but wider aper- tures, pierced at the inferior face of the bone, and for this reason named the subsacral fo- ramina, The inferior face is smooth, and shows traces of the primitive separation of the ver- tebral bodies ; the subsacral fo- ko EBA VIEW OR SCRUM ramina, which represent, with sy i begat body ie oe shacks the corresponding supersacral o¢ ee terete sia no ig “ 5 race oe ! f° rtebra; 4, Spinal foramen; 5, openings, the intervertebral fo- Auricular facet; 6, Anterior articular processes; ramina of the other regions of 7, Inferior or subsacral foramina; 8, Superior the spine, are observed on this spinous processes; 9, Summit or coccygeal ex- tremity. surface. Borders.—The two borders, thick and concave, form, posteriorly, a rugged lip; in front, they present an irregular surface inclining obliquely from above to below, from within outwards, and from before to behind. This surface, which is intended for the articulation of the sacrum with the ossa innominata, is divided into two parts: one, the inferior, named in man the auricular facet, is slightly undulated and diarthrodial; the other, the superior, serves for ligamentous insertions. Base.—This offers: 1, On the median line, the anterior orifice of the sacral canal, and the anterior articular surface of the body of the first sacral vertebra, which is oval and slightly convex; 2, On the borders, the articular processes and anterior notches of this vertebra, as well as the elliptical and somewhat convex facets which bring it into contact with the transverse processes of the last lumbar vertebra. Summit.—The summit. thrown back, presents: 1, The posterior orifice of the sacral canal; 2, The posterior articular surface of the body of the last sacral vertebra; 8, The vestiges of the articular processes and posterior notches of that vertebra. Sacral canal—This is the portion of the spinal canal which is channeled out of the sacrum; it is triangular, and diminishes in width from before to behind. 5. Coccygeal Vertebree. The coceygeal region, or coccyx, comprises from fifteen to eighteen de- generate vertebre, which gradually diminish from the first to the last. In the first three or four, nearly all the characteristics of true vertebre are found; they show a spinal foramen, a body, a spinous process, and transverse processes, looking backwards; the articular processes only are altogether absent. In the succeeding vertebre, these characters become effaced ; the vertebral lamina do not join completely, and the spinal canal is only a simple groove, which, gradually decreasing in depth, at last 28 THE BONES. entirely disappears. The insertion eminences also become less salient, and the coceygeal vertebre are soon reduced to small bony cylinders, narrow in the middle and wider at both extremities, with a convex articular surface at each end (except the last, which has only one articular surface). These small cylinders, the last traces of the vertebral bodies, are each developed from three centres of ossification ; they are very spongy and light. The first coceygeal vertebra is frequently consolidated with the sacrum in aged animals. THE SPINE IN GENERAL. The vertebral column has now to be considered in its entirety, and examined successively in its superior face, its inferior face, its lateral faces, and its spinal canal, Afterwards its direction and mobility will be noticed. Superior face.—This presents, on its median line, the series of spinous processes. But little salient in the cervical region, these eminences are much developed in the dorsal and lumbar, where they constitute a long crest, the dorso-lumbar spine, as well as in the sacrum, where they form the sacral spine. They soon disappear in the coccygeal vertebra. Outwards, and on each side of these processes, is seen a succession of tubercles of insertion, represented in the cervical and lumbar vertebre by articular processes, and in the dorsal vertebra by the superior or rugose portion of the transverse processes. These tubercles are disposed in line, and separated from the spinous processes by a channel designated the vertebral groove, which is more or less deep and wide. It is on these, and on the spinous processes, that the extensor muscular fasciculi of the spine receive the greater portion of their fixed or moveable insertions. Inferior surface.—Wide at the neck, this face becomes narrow in the dorsal region, to be again widened at the lumbo-sacral region, and once more contracted at the coccyx. Crests more or less developed, which divide the vertebral bodies into two lateral portions, right and left, are remarked. Lateral surfaces.—These offer for study the thirty-six intervertebral foramina, through which the spinal nerves pass. They exhibit besides, on the neck, the transverse processes; in the back, the external facets of these processes, and the intervertebral facets, all destined to sustain the heads of the ribs; on the loins, the transverse or costiform processes. It may be remarked that the ribs and the transverse processes of the neck and loins furnish points of insertion to the powerful muscles which produce the lateral movements of the spine. In the sacrum, the lateral faces are formed for the articulation of the spine with the ossa innominata. Spinal canal.—This canal communicates, in front, with the cranial cavity. Very wide in the atlas, for the reception of the odontoid process and to permit the rotatory movements of the head without injury to the spinal cord, this canal suddenly diminishes in the axis. It again dilates at the termination of the cervical region and the commencement of the dorsal; there the spinal cord presents a greater volume, and the movements of the spine are very extensive. Towards the middle of the back, the spinal canal offers its smallest diameter; it widens from this part to the lumbo-sacral articula- tion; after which it contracts rapidly, and disappears altogether near the fourth or fifth coccygeal vertebra. The lumbo-sacral dilatation coincides with the enlargement of the cord in this region, and with the enormous quantity of nerves lying beside it. THE VERTEBRAL COLUMN. 29 Direction of the vertebral column.—The spine does not extend in a straight line from the head to the posterior extremity of the body. If it is followed from the caudal termination, which is free and looks downwards to the anterior extremity, it will be seen that it rises upwards and forwards, forming a convex inflexion corresponding to the roof of the pelvis. Tn the lumbar and the posterior half of the dorsal region it is nearly horizontal and rectilinear; from thence it descends to the cervical region, when it again rises and forms two curves, the one posterior, bending upwards, the other anterior, turned down. This disposition of the cervical spine gives it the shape of a console. Mobility of the vertebral column.—In the cervical region, the almost total absence of spinous processes, the great development of the articular processes, and the very short curve described by the surfaces of contact of the vertebral bodies, allows the spine very extensive and very diverse movements. In the dorsal region, however, these movements are very limited, the spinous processes and the costal arches preventing the play of the vertebre on each other. In the lumbar region, the spine can be flexed or extended more than in the dorsal; but its lateral movements are quite as restricted, owing to the presence of the transverse processes and the reciprocal joining or dovetailing of the articular processes. Lateral motion is even rendered impossible in the posterior half of this region, from the manner in which the transverse processes are adapted to each other. It may be remarked, however, that this disposition singularly favours the integral transmission of the propulsive efforts thrown upon the trunk by the posterior extremities. The sacral vertebra, having to afford the ossa innominata a solid fixed point, could not preserve their independence and mobility, and are conse- quently consolidated into a single piece which fulfils all its requirements in this respect. In the coccyx the rachidean stalk again recovers its mobility, and to a degree more marked than elsewhere ; the coccygeal bones, articulated with each other by means of convex surfaces, and deprived of long processes at their extremities, are placed in the best possible conditions for variety and extent of movement, DIFFERENTIAL CHARACTERS IN THE VERTEBRAL COLUMN OF OTHER THAN SOLIPED ANIMALS. The NumBer of Pieces composing the Sprvz slightly varies in the Domesticated Animals, as will be seen in the following Tas. VERTEBR&, ANIMALS, Cervical. Dorsul. Lumbar. Sacral. Coccygeal. Ox . 7 13 6 5 16 to 20 Sheep 7 13 6 or 7 4 16 to 24 Goat 7 13 6 4 11 to 12 Pig . 7 14 6 or 7 4 | 21 to 23 Dog 7 13 7 3 16 to 21 Cat . 7 13 7 3 21 A. VERTEBRE or THE Ox, SHEEP, AND Goat.—1. Cervical Vertebrx.—The cervical vertebrae of the Ox differ from those of solipeds by their shortness and the greater deve- lopment of their insertion eminences. In the Sheep and Goat they are relatively longer than in the Ox. The transverse processes of the atlas are less inclined than in the Horse, 30 THE BONES. and have no vertebral foramina; the posterior facets for articulation with the axis are nearly flat and join each other. The axis has a semicylindrical, not a conical, odontoid process, which is so concave on its upper surface that it looks like a groove. Its spinous process is not so thick as in the Horse, and is not bifid posteriorly. . . In the jive succeeding vertebre, a rugged continuous lamina unites the anterior articular “processes to the posterior. The spinous process inclines forward and is flattened trans- versely at its summit, which is sometimes bifid; it augments progressively in height from the third to the fifth vertebra. : ; In the sixth, the transverse processes have only two prolongations—a superior and inferior; the latter, large and flattened on both sides, is bent abruptly downwards. ‘The spinous process has already attained the height of 14 to 2 inches in this vertebra, and is flattened laterally. : The seventh well deserves the name of prominens: its spinous process being no less than from 4 to 43 inches. 2. Dorsal vertebre.—In the Ox these bones are longer and thicker than in the Horse. Their spinous processes are larger and incline more backward ; their transverse processes are very voluminous, and are provided with a convex facet from above to below; while their posterior notches are nearly always converted into foramina. - Considered individually, they are more slender in the middle than at the extremities. Their spinous processes diminish in width, especially at their summits, from the first to the eleventh vertebra, and widen again in the two last; they progressively increase in slope to the tenth, after which they become more and more upright; the first four are the longest, and are nearly the same in height; the others gradually decrease. In the first four or five vertebra, the articular facet of the transverse processes, while retaining its vertical convexity, is concave in an antero-posterior direction. This facet is always absent in the last vertebra, and sometimes even in the preceding one. The two bones terminating the dorsal region show, in addition, the articular processes disposed like those of the lumbar vertebrae. The dorsal vertebree of the Sheep and Goat are relatively less strong than those of the Ox; their spinous processes are not so wide, and their posterior notches are never con- verted into foramina. 3. Lumbar vertebrx.—The lumbar vertebre of the Ox are longer and thicker than in the Horse. The transverse processes are also generally more developed, are concave on the anterior border, convex on the posterior, and incline slightly downward, with the exception of the two first, which remain nearly horizontal. They increase in length from the first to the fourth vertebra; in the latter and the fifth, they are nearly of the same dimensions; in the last they suddenly become shorter. Their width gradually decreases from before to behind. In the fifth and sixth vertebra, these processes have no articular facets between them and the sacrum, these being only met with in solipeds. The artic- ular processes are prominent, and further removed from the median line as they belong to posterior vertebra. In the Goat the transverse processes are more inclined downwards. In the Sheep, on the contrary, the processes rise up towards their extremities. 4. Sucrum.—The sacrum of the Ox is more voluminous and curved than that of the Horse. The spinous processes are entirely consolidated, and are surmounted by a thick rugged lip; they are lengthened at their base and on each side by a ridge that represents the rudiments of the articular processes, The lateral borders are sharp and bent down- wards, The surfaces that serve to unite the sacrum to the ossa innominata have a some- what vertical direction. There are no lateral facets on the base of the bone for the union of the sacrum with the transverse processes of the last lumbar vertebra. In the Sheep and Goat, the sacrum is shorter; sometimes the consolidation of the spinous processes is late, or never occurs. 5. Coceygeal vertebre.—In proportion, the coccygeal vertebre of ruminants are stronger and more tuberous than those of the Horse. The anterior articular processes exist in a rudimentary condition. :B. Verreseex or tus Pic.—l. Cervical vertebrx.—Of all the domesticated animals, this has the shortest, the widest, the most tuberous, and consequently the strongest cervi- cal vertebre. The body of these bones is deprived of its crest on the inferior face ; its head, but little detached, is scarcely round, and looks as if driven back on itself ; con- sequently, its posterior cavity is not deep. The vertebral lamin are very narrow, and scarcely extend from one part of the vertebra to the other in the superior portion; so that the spinal canal appears at this point to be incomplete. In the atlas, the transverse processes are yet. less inclined than in ruminants; the vertebral foramen is not constant, and when it exists, opens on one side, under the THE VERTEBRAL COLUMN. 31 transverse process, and on the other, on its posterior margin, after pursuing a certain track in the substance of the bone. The odontoid process of the aais is constricted at its base. This vertebra is distin- guished by its high and thin spinous process inclining slightly back, by its transverse processes being but slightly prominent and perforated by an enormous vertebral foramen. In the four succeeding vertebre, the spinous process terminates in a blunt point, and inclines forward ; slightly salient in the first, it gradually rises in the others. ‘The trans- verse processes form two prolongations: one, the superior, is tuberculous, and is joined to the anterior articular process by a plate of bone, which is pierced by a foramen; the other, the inferior, flattened on both sides, bent downwards, and large, as it belongs to the posterior vertebree, transforms the inferior face of these vertebral bodies into a large groove. The seventh is provided with a spinous process as long as those of the dorsal region. A perforated bony plate, as in the preceding vertebrae, unites the anterior articular process to the single tubercle composing the transverse process; the latter is continued back nearly to the pusterior notch by a second plate, also perforated with a foramen (see Fig. 2). 2. Dorsal vertebre—The Pig has fourteen dorsal vertebrae, which, in their general disposition, are not unlike those of the Ox. As with that animal, the intervertebral fora- mina are double, each vertebral lamina being perforated laterally by an opening situated in front of the posterior notch. In addition, the vertebre of the Pig present this pecu- liarity, that their transverse processes are generally traversed at the base by a single or multiple foramen which communicates with the preceding. With regard to the special characters proper to some of the vertebra, these are, as with the other animals, very few, and may be described as follows: 1. The transverse pro- cesses of the four vertebra preceding the last project but slightly; 2. In the fourteenth this process resembles those of the lumbar vertebre; 3. The articular facet of the trans- verse process in the four last vertebrae is confounded with the anterior lateral facet corresponding to the head of the rib, 4. The articular processes of the last five vertebree are arranged like those of the lumbar vertebre ; and the prominence formed by the tubercle on the outside of the anterior articular process replaces, to a certain degree, the transverse process of these vertebree. é , 3. Lumbar vertebre.—These bones in the Pig greatly resemble those of ruminant animals. It commonly happens that seven are met with; but in this case the supple- mentary vertebra is generally a sacral one. It is not denied, however, that seven lumbar vertebree may exist in the Pig, along with the normal number of sacral vertebre. 4. Sacrum.—This is formed by four vertebrae, which are a long time in becoming fused together, and it is often difticult to discover where the sacrum ends and the coccyx begins! The spinous processes are entirely absent. The vertebral laminw are not consolidated ; so that the spinal canal is half cut through in its upper portion, as in the cervical region; this canal is also much compressed above and below. 5. Coccygeal vertebre—These vertebre in the Pig are more particularly distin- guished by the presence of articular processes, by means of which the foremost bones correspond with each other. C. VexTesre or tHE Dog anp Cat.—l. Cervical Vertebrx.—In these animals, the cervical vertebre are long and thick, and much resemble those of solipeds. Nevertheless, besides their smaller volume, they are distinguished: 1, By the disposition of their corresponding articular surfaces; the anterior, or head, is nearly flat, and is even slightly excavated in its centre; the posterior, or cavity, is but little hollowed to receive the head of the next vertebra; 2, By the width of the vertebral lamine, which exactly cover one another; 3, By the height of their spinous processes, which increases as the vertebra extend back; 4, By the great extent of the anterior and posterior articular processes, which are united by means of a continuous and very salient bony plate, that considerably augments the transversal diameter of each vertebra. ; f / In the atlas, the articular surface for the odontoid pivot is confounded in front with the cavities which correspond to the occipital condyles. The two facets which are annexed posteriorly to this articular surface, instead of being plane or gently undulated, as in the 1This can always be made out, however, by consulting the disposition of the articular processes. Thus, in the sacral vertebra these eminences—if we except the anterior ones of the first and the posterior of the last—never exist except in a rudi- mentary state; while in the other five coccygeal vertebre they re-appear with all their characters. 32 THE BONES. other domesticated animals, are transformed into real glenoid cavities.) The transverse processes are carried directly outwards and a little backward; the lip which borders each is slightly raised; of the two foramina which replace the anterior notch, one only exists, and this penetrates to the interior of the spinal canal; the other is merely a simple notch. In the axis, the odontoid process is cylindrical, narrow at its base, and bent a little upwards; the lateral facets of this eminence represent true condyles? The spinous process is very thin and undivided, and is curved forward above the lamine of the atlas. The anterior notches are never converted into foramina. The third cervical vertebra is the largest, and the succeeding ones gradually diminish in thickness to the last, contrary to what occurs in the other species. The seventh does not show the spinous process so developed as in ruminants and pachyderms see Fig. 1). f 2. Fonaal vertebr.—In the Dog the dorsal vertebra are formed on the same model as those of the Horse; but their spinous processes are in general narrower and thicker. The tenth always has its spinous process vertical, triangular, and terminated in a sharp point. The last three have no posterior facets for the articulation of the heads of the ribs, and exhibit, in the conformation of their articular processes, the same disposition as the lumbar vertebra. In the Cad, the transverse processes of the three last dorsal vertebrae are thin, sharp, and turned backwards, they never possess facets for the tuberogity of the ribs. 3. Lumbar vertebre.—In the Dog and Cat, the lumbar vertebre are remarkable for their strength, due to their length, thickness, and the development of the eminences of inseition. ‘The spinous process is low, and becomes acute in the last vertebra. The transverse processes incline very much forward and downward ; they become longer from the first to the second-last bone, in the latter they become contracted, and in the seventh vertebra they are still more diminished, and terminate in an obtuse point. The tubercle of the anterior articular process is extremely prominent, and the posterior notches are surmounted by a small, very acute prolongation, directed backwards, which becomes more developed towards the anterior vertebre. This small prolongation exactly represents the transverse process of the dorsal vertebrae. 4. Sacrum.—The three vertebre which form the sacrum of carnivora are early con- solidated. The supersacral spine constitutes a thin sbarp ridge; while the lateral surfaces for articulation with the ossa innominata are turned quite outwards and are nearly vertical. 5. Coecygeal vertebrex.—The vertebre of the coecyx are very strong and tuberous, The first five or six are as perfect as the true vertebree, and comport themselves in every respect like them. The last are small V-shaped bones, which M. Goubaux has described by the name of hypstloid bones. COMPARISON OF THE VERTEBRAL COLUMN OF MAN WITH THAT OF THE DOMESTICATED ANIMALS. The vertebral column of Man is composed of twenty-nine bones . twenty-four vertebra, the sacrum, and four pieces constituting the coccyx. The twenty-four vertebre are thus distributed : Cervical vertebrae Pia ie £5 7 Dorsal 4s etal Leo bys 1g gtk Lumbar ‘3 a" us , 5 _ Inall these vertebra, the bodies are slightly excavated at the two extremities, while in the domesticated animals, the superior or anterior is convex, and the inferior or posterior concaye. 1. Cervical vertebre.—These are wide and. short. The spinous processes are mode- rately developed and bifid at their summits; the transverse processes are also divided into two branches—a posterior and an anterior. 2. Dorsal vertebre.—In these vertebrae, the bodies increase in thickness from the first to the last. In the first as well as in the last dorsal vertebree, the spinous process is almost immediately directed backwards; in the middle portion of this region these processes are very obliquely directed downwards and backwards. : (A glenoid cavity is a shallow, oval, articular depression.) (A condyle is an articular eminence representing an ovoid segment, Condyles always correspond to the glenoid cavities in the articulations.) THE HEAD. 33 3. Lumbar vertebre.—The lumbar vertebree are the strongest bones in the spine, and their bodies are nearly as thick as those of the larger domesticated animals, This enormous development of the lumbar vertebree in Man is related to his positi i : 7 : a position as a biped. In the fifth, the lower face of the body is cut very obliquely backwards and upwards, pnd the transverse processes are more voluminous than those of the other lumbar vertebra. 4. Sacrum.—The sacrum is formed by the union .of five pieces. It is very concave from above to below and before to behind. In becoming united to the lumbar region, it forms a salient angle in front, to which has been given the name of promon- tory or sacro-vertebral angle. The sacral spine is continuous or interrupted, according to the subject; it is alway bifid inferiorly. 5. Coccygeal vertebre.—These are little bones or flattened tubercles, four in number, rarely five, and usually consolidated. ‘The coccyx is conical in shape. Its base shows two processes directed up- wards, which are called the cornua of the coccyx. Tts summit is often deviated to the right or left. ArticLe [].—THe Heap. The head is a large bony pyramid, elon- gated from above to below, and quadran- gular, suspended to the anterior extremity of the spine ; it is in a direction varying with the attitudes of the animal, but which we will suppose, for convenience of description, to be nearly vertical. It is formed of a great number of particular bones, which are only distinct from one another in very young animals; for well before the adult period is reached the majority of the bones are united and cannot be separated. The head is divided into two parts: the cranium and the face. BONES OF THE CRANIUM. The cranium, or upper part of the head, is composed of seven flat bones, five of which are single: the occipital, parietal, Frontal, sphenoid, and ethmoid ; one only, the temporal, is double. These bones cireum- scribe a central cavity, the cranial, which communicates behind with the spinal canal, and lodges the principal portion of the nervous centres—the encephalon. 1, Occipital Bone. The occipital bone occupies the superior extremity of the head, which it supports from the anterior extremity of the spine. This bone is very irregular in its form, and is bent at a right angle in front and behind. Tt has an eaternal and an internal face, and a circumference which brings it into contact HORSE’S HEAD; FRONT VIEW. 1, Occipital protuberance ; 2, Origin of the mastoid crest; 3, Parietal bone; 4, Saggital suture; 5, Junc- tion of the parietal and temporal bones; 6, Zygomatie arch; 7, Frontal bone; 8, Frontal suture ; 9, Temporal fossa ; 10, Supraorbi- tal foramen; 11, 12, Lachrymal bone; 13, Malar bone; 14, Nasal border of frontal bone; 15, Nasal bone; 16, Suture of nasal bones ; 17, Superior maxillary bone; 18, Infraorbital foramen; 19, Ante- rior, or pre-maxillary bone; 20, Foramen incisivum; 21, Incisor teeth—young mouth. with the adjoining cranial bones ; the latter is subdivided into two anterior 84 THE BONES. lateral borders, two posterior lateral borders, an anterior and posterior salient angle, and two lateral re-entering angles. : Faces.—The external face is dividéd into three portions by the double flexure of the bone: one looks forward, another upward, and the third backward. It exhibits:—1. On the median line, and from before to behind : a, an antero-posterior ridge which constitutes the origin of the parietal ridges, to be mentioned hereafter; b, a transverse, voluminous, and very prominent eminence, marked posteriorly by deep imprints, with a medium projection named the cervical tuberosity; this is the eaternal occipital pro- tuberance which, in the Horse, corresponds at the same time to the superior curved lines of the occipital bone of Man. This protuberance forms the culminating point of the head, and divides the anterior and superior parts of the external face of the bone; ¢, the occipital foramen (foramen magnum), a large orifice that passes through the bone at the posterior flexure, and esta- blishes a communication between the cranial cavity and spinal canal; d, the external surface of the basilar process, a narrow and thick prolongation formed by the bone as it passes to meet the sphenoid : this surface is convex laterally. 2. On the sides: a, A sharp crest which prolongs, laterally, the superior curved lines, and descends on the middle of the lateral anterior border to be continued with the superior root of the zygomatic process and the mastoid crest of the temporal bone; b, Linear imprints, parallel to the latter, and prolonged on the base of the styloid process: they are destined for the insertion of the small oblique muscle of the head, and represent the inferior curved lines of the occipital bone of Man ; c, Within these imprints is a slightly- roughened cavity for the insertion of the posterior recti muscles; d, The two condyles, articular eminences with a double convexity, one superior, the other. inferior : these eminences are situated on each side of the occipital foramen (foramen magnum), and correspond to the anterior cavities of the atlas; e, More outwards are the two styloid processes, or jugular eminences, long projections flattened on each side, terminated in blunt points, directed back- wards, and separated from the condyles by a deep space, the stylo-condyloid. notch; f, Under the condyles is the condyloid fossa, a smooth depression, pierced at the bottom by the condyloid foramen, which penetrates the cranium. The internal face of the occipital bone is concave, and shows :, behind, the foramen magnum ; above, an uneven surface, which forms the roof of the cerebral cavity; below, the superior face of the basilar process, slightly hollowed into a groove; on the sides, the internal orifice of the condyloid foramen. Circumference.—The anterior lateral borders are thick, and are united by suture with the parietal bone, and with the tuberous portion of the tem; oral bone by the harmonia! suture. The posterior lateral borders are sharp, and constitute the sides of the basilar process; each concurs in the formation of the occipito-spheno-temporal hiatus, also termed the lacerated foramen, a vast irregular opening, extending from above downwards, penetrating the cranium, and divided by a ligament, in the fresh state, into two portions, one inferior, the anterior lacerated foramen, the other superior, the posterior lacerated foramen. The anterior angle, which is dentated, is dovetailed into the parietal bone. The posterior angle is very thick, and forms the summit of the basilar process; it is united by suture with the body of the sphenoid. The lateral re-entering angles, or jugular notches, correspond to the 1 (The harmoni iy, t i i ition « i : ace are esha abet reel hear asi 6 atic aa ® (The anterior and posterior lacerated foramen of Man.) THE HEAD. 35 point where the bone is bent posteriorly ; they separate the anterior lateral from the corresponding posterior lateral border, and are occupied by the tuberous portion of the temporal bone. Structure.—The occipital bone contains much spongy substance. Development.—It is developed from four centres of ossification : one, the anterior, is single, and forms the occipital protuberance; another ” the posterior, also single, forms the basilar process; the other two are pairs, and comprise each a condyle, with the styloid process and the corresponding condyloid foramen. 2. The Parietal Bone. The parietal is a wide and thin bone, very much arched to form the roof of the cranial cavity. It is bounded above by the occipital bone, below by the frontal, and laterally by the two temporal bones. It offers for study on is and internal face, and a circumference divided into four regions or orders. ; Faces.—The external face is convex. It exhibits two curved ridges whose concavity is directed outwards; these two crests, which are termed the parietal ridges, approach each other and unite superiorly, to be continued with the antero-posterior ridge of the occipital bone; below they diverge and proceed, one on each side, to join the supraorbital process. They divide the surface of the bone into three portions: two lateral, which are rough and traversed by vascular channels, forming part of the temporal fosse ; the third, or middle, is plane, smooth, and of a triangular form, and covered by the skin. The internal face is concave, covered by digital impressions, and grooved by small vascular canals; it offers, on the median line, and altogether above, the parietal eminence.’ This trifacial and very salient pro- jection presents at its base, on each side, an excavation elongated trans- versely, into‘which opens the parieto-temporal canal, and which is destined ve tO lodge a venous sinus. It is continued, in front, by a median crest, which is often replaced by a slight groove, the saggital furrow, bordered by linear imprints. Two other ridges, resulting from the abutment of the lateral border of the bone against the anterior face of the petrous bone, rise from the sides of this eminence and descend to the sphenoid bone; they separate the cerebral from the cerebellar cavity. Borders.—The superior border is notched, thick, and slightly dentated ; it articulates with the occipital bone. The inferior border, slightly concave, and deeply dentated, offers an external bevel in its middle portion, and an’ infernal bevel on its sides; it corresponds with the frontal bone. The late ul borders are very thin, and are cut at the expense of the external plate into a wide, sloping edge, which shows a groove destined to form the parieto-temporal canal. A very prominent angle separates each into two portions, an inferior, that articulates by suture with the squamous portion of the temporal bone ; and a superior, curved inwards towards the centre of the cranial cavity; the latter portion of the lateral border is in contact with the anterior face of the petrous portion of the temporal bone, with which it concurs to form the lateral crest that descends to the parietal eminence. . Structure.—This bone contains much compact tissue, the spongy sub- stance existing only in its middle. ; : Development.—It is developed from two large centres of ossification, to 1 The internal occipital eminence of Man, 36 THE BONES. which is added a single centre to form the parietal eminence.’ In early life the parietal ridges are absent. 3. Frontal Bone. © The frontal is a flat quadrilateral bone, whose sides are bent in the middle at an acute angle, and are carried back, and a little inwards, to meet the wings of the ‘sphenoid bone. It assists in forming the cranial roof and part of the face. It is bordered: above, by the parietal bone; below, by the nasal and lachrymal bones; and on each side, by the temporal bones. It offers for study an external and an internal face, and four borders. Faces.—The external face is divided, by the double flexure of the bone, into three regions: a middle and two lateral. The first, nearly plane, is lozenge-shaped, is covered by the skin, and constitutes the base of the fore- head. It gives rise on each side, at the point where it is inflected, to a long process, flattened above and below, which curves backward, forming the orbital arch. The superior or external face of this process is convex and slightly roughened ; the internal face is smooth and concave, and forms part of the orbital fossa. Its posterior border, thick and concave, is continued, in- wardly, with the corresponding parietal ridge, and outwardly with the superior border of the zygomatic process. It limits, in front, the temporal fossa. The anterior border, also concave, but thin, concurs in the forma- tion of the orbital margin; the summit, thickened and denticulated, rests upon, and is united to, the zygomatic process of the temporal bone; the base is wide, and is traversed by an opening termed the supraorbital, or super- ciliary foramen. The two lateral regions of the external face of the frontal bone are slightly excavated, and assist, for the greater portion of their extent, to form the orbits. They often show, near the base of the orbital arch, a small depression corresponding to the flexure described by the great oblique muscle of the eye in passing through its pulley. ; The internal face of the frontal bone is concave, and divided into two unequal parts by a transverse ridge, corresponding to the anterior border of the cribriform plate of the ethmoid bone. The superior, the most extensive, is covered with digital impressions, and belongs to the cranial cavity. It exhibits: 1, On the median line, a slight furrow, or a crest which is con- tinuous, above, with the median ridge of the parietal bone, and below, with the crista-galli process ; 2, On the sides, and in the re-entering angle formed by the flexure of the boné, there is a narrow slit, or mortice, which receives the wing of the sphenoid bone. The inferior part is united, on the median line, to the perpendicular plate of the ethmoid. It assists in forming the bottom of the nasal cavities, and presents laterally two large openings which lead to the frontal sinuses—vast anfractuous spaces excavated between the two plates of the bone. Borders.—The superior border is denticulated, and cut obliquely, in its middle portion, at the expense of the internal plate, and on the lateral pdrts at the expense of the external table; it is in contact with the parietal and ' This centre is described as the interparietal bone by those anatomists who consider the two lateral centres as two distinct parietals. (Leyh is one of the veterinary anatomists who describe this nucleus as a separate bone, designating it the falciform or interparietal bone. He also describes the parietal as a pair or double bone; whereas the majority of French anatomists include the interparietal bone as the median protuberance of the parietal, which they look uponas a single or impair bone. Percivall names it a pair bone, but follows the example of the French hippotomists with regard to the interparictal.) THE HEAD. 37 squamous portion of the temporal bone. The inferior, prolonged tu a point in the middle, is in apposition with the nasal bones through the medium of a wide external bevel; laterally, it is very thin, faintly serrated, and articulates with the lachrymal bone. The lateral borders, thin and irregular, present two notches: one, the superior, is wide and deep, and occupied by the wing of the sphenoid bone; the other, inferior, is very narrow, and uniting with a similar notch in the sphenoid bone, forms the orbital foramen, which opens into the cranium, very near, but external to, the ethmoid fossa. Each of these borders, also, is adapted, for a limited extent, to the corresponding palate bone. * : Structure.—The two compact plates of the frontal bone are separated by spongy texture towards the middle and in the upper part; they separate below to form the frontal sinuses. Laterally, they are very thin and consolidated with each other. Development.—The frontal bone is developed from two lateral centres of ossification, which only coalesce at a late period. In youth the cranial portion of the bone forms, in front of the head, a large rounded protuberance standing beyond the facial portion. This prominence disappears when the frontal sinuses begin to be developed. These cavities do not exist at an early period of foetal life ; but commence to form about the fourth month of conception, by a process of resorption, which removes the spongy substance interposed between the two compact tables of bone, and may even cause the destruction of the internal table. The sinuses enlarge with age, and remain during life separated from one another by a vertical septum. 4, Ethmoid Bone. The ethmoid bone, deeply situated in the limit between the cranium and the face, is inclosed between the frontal, the sphenoid, the vomer, the palate, and the supermaxillary bones. It is composed of three portions: a perpendicular plate, and two lateral masses. Tue Prrrsnpicunar Lamina or tHe Eramor Bonz.—Situated in the median plane, and flattened on both sides, this bone presents two faces, a left and right, and four borders. Faces—The faces, covered by the pituitary membrane, present, pos- teriorly, small sinuous crests; elsewhere they are smooth. A very narrow interval, constituting the bottom of the nasal cavities, separates them from the lateral masses. Borders.—The superior border looks towards the centre of the cranial cavity, and constitutes what is called the ethmoidal ridge, or crista-galli process. It is free, concave, and sharp, prolonged in front and above by the median crest of the frontal bone, and confounded behind with the middie portion of the inferior sphenoid. The inferior border is continuous with the cartilaginous plate which separates the nasal cavities. When this plate becomes ossified, which is not unfrequent, it is impossible to discover the point where it begins or the ethmoid bone terminates. The middle septum of the mose has been considered, and justly, as a prolongation of the perpen- dicular plate (or lamina) of this bone. The anterior border is consolidated with the vertical septum which separates the frontal sinuses. The posterior border is joined, above, to the median plate which divides the sphenoidal sinuses into two compartments. Below, it is fixed in the groove of the vomer, and goon becomes confounded with that bone, which is itself conso- lidated with the inferior sphenoid. Lateran Masszs or THE Eramor Bons.—Theso are two large pyriform 6 38 THE BONES. tuberosities placed on each side of the perpendicular lamina, and offering for study a middle portion, a base, and a summit. Each of these is formed by an assemblage of numerous, extremely thin, osseous plates, curved into small and very fragile convolutions. These, elongated from above to below, become longer as they are more anterior; they are attached by their superior extremities to the transverse plate which separates the cranium from the nasal cavities, and by one of their borders to a thin leaf of bone which Fig. 19. ANTERIOR BONES OF THE HEAD OF A FETUS (HORSE) AT BIRTH; VIEWED FROM BEHIND, DISARTICULATED, AND envelops the lateral masses out- wardly. They have received the name of the ethmoidal volutes (or cells). Middle portion.—This should be studied externally and inter- nally. The eaternal surface of each ethmoidal mass is divided into two sections: an internal, making part of the nasal cavities; the other, external, concurs in form- ing the walls of the frontal and maxillary sinuses. The first, the least extensive, is almost plane; parallel to the perpendicular la- mina, it is isolated from it by the narrow space which forms the bottom of the nasal cavities; it presents several openings which separate the most superficial cells, and join the internal canals to be hereafter noticed. The second, A, Occipital bone.-—1, Condyle; 2, Con- dyloid foramen; 3, Styloid process; 4, Summit of basilar process.—x, Parie- tal bone.—8, Parietal protuberance; 9, Channel which concurs to form the parieto-temporal canal.—c, Frontal bone.—10, Transverse crests separating the cranial from the facial portion of the bone; 11, Frontal sinuses; 12, Notch on the lateral border occupied by the wing of the sphenoid bore; 13, Notch for the formation of the orbital foramen; 14, Summit of the orbital Process; 15, Supraorbital foramen.— D, Perpendicular lamina of the ethmoid bone.—x, ©, Lateral masses of ithe eth- moid bone.—16, The great ethypoid cell. —F, Squamous portion of the;temporal bone—17, Supercondyloid process ; 18, Channel for the formation of the parieto-temporal canal.—a, Tuberous portion of the temporal bone.—5, Mas- toid process; 6, Internal auditory hiatus; 7, Opening for the eustachian tube into the tympanum.—x, Lach- rymal bone.—z, Nasal bone—J, Su- perior turbinated bone, THE HEAD. 39 very extensive and convex, looks outwards in front and behind, and is covered by an osseous plate traced with shallow furrows, which correspond internally with the small crests to which the cells are attached. This lamella is prolonged, inferiorly, a little beneath the inferior extremity of these latter, and turns outwards to articulate with the palate and superior maxillary bones ; superiorly, it coalesces with the sphenoid and the orbital portion of the frontal bone. Internally, the lateral masses are hollowed from above to below by extremely diverging canals, which open inferiorly into the nasal cavities, and separate the cells from one another. ‘The latter are so incurvated that the internal cells communicate with each other. There are some, however, which are completely closed ; the anterior, or great cell, is frequently so. Base.—The base of each lateral mass looks upwards, and is formed by the transverse septum between the cranium and the nasal cavitics. This septum is perforated by openings which give passage to the ethmoidal nerves ; it is named the cribriform plate of the ethmoid bone. It is concave on the superior surface, which constitutes the ethmoidal fossa, and convex on the opposite face, where attachment is given to the superior extremities of the cells. It is consolidated internally with the perpendicular plate; the other points of its circumference are attached to the sphenoid bone, and to the transverse ridge on the internal face of the frontal bone. Summit.—The summit of each lateral mass is formed by the inferior extremity of the ethmoidal cells, which is directed downwards towards the nasal cavities. One, more voluminous than the others, is carried much lower, and terminates by a rounded protuberance. It corresponds to the middle cornu (concha media) of Man. Structure of the ethmoid bone.—Very little spongy tissue enters into the composition of this bone, and this is only found near the anterior border of the perpendicular plate. Development.—The ethmoid bone is late in attaining its development, and the adjoining bones are nearly completely ossified when it is yet entirely cartilaginous. The bony transformation commences in it at the inferior extremity: of the cells, and advances progressively from below upwards. The perpendicular plate is only ossified in part when the cells have passed through the first half of the process; at the same time it coalesces with the inferior sphenoid. The cribriform plate is the last to become ossified; this transformation having scarcely been achieved when the animal is six or eight months old. 5. Sphenoid Bone. The sphenoid bone is situated behind the cranium, between the occipital, ethmoidal, palate, vomer, pterygoid, frontal, and temporal bones. It is flattened from before to behind, curved from one side to the other, thick in its middle part, named the body, and thin on the sides, which, in their inferior half, are prolonged in the form of alc or wings. Tt has two surfaces and four borders. : Surfaces.—The external surface 18 convex, and presents: 1, On the median line, the external surface of the body, rounded from one side to the other, is continued with that of the basilar process, and has marked mus- cular imprints superiorly; 2, On the sides and from within outwards: a, the videan (or pterygoid) fissure, directed from above downwards, and con- tinued by the vidian canal, a very small foramen which opens into the 1 Tt ig not rare to find it opening into the frontal sinus. 40 THE BONES. orbital hiatus; b, the subsphenoidal, or pterygoid process, a long eminence, flattened on both sides, inclining downwards, articulating with the palate and pterygoid bones, and traversed at its base by the vidian canal; c, a little behind and above this eminence, the superior orifice of the sub- sphenoidal foramen, a large canal which bifurcates inferiorly ; d, more in front, the orbital hiatus, a kind of vestibule into which open in common the principal branch of the subsphenoidal canal, the three supersphenoidal canals, the vidian and optic canals, and the orbital opening: this hiatus is surmounted by a thin and sharp bony plate, above which opens the smallest branch of the subsphenoidal foramen; e, altogether without the hiatus is remarked a smooth surface belonging to the wing of the sphenoid, and which concurs to form the orbital cavity. The internal face is concave from side to side. It shows: 1, On the median line, and from before to behind, a small projection united to the crista-galli ; the optic fossa, elongated transversely in the form of a shuttle, and presenting at the bottom, and on each side, the superior orifice of the optic foramen, a cylindrical canal directed obliquely downwards, forwards, and outwards, to reach the orbital hiatus; the supersphenoidal or pituitary fossa, also named the sella turcica, a slight depression, limited behind by a scarcely noticeable transverse projection separating it from the superior channel of the basilar process; 2, On the sides, and in front, the internal surface of the wings, depressed by very superficial digital impressions ; more behind and outwards, a fossa, elongated from before to behind, which lodges the mastoid lobule of the brain; between this fossa and the sella turcica, two vertical fissures : an internal, named the cavernous sinus, and an external, wider and deeper, for the passage of a large nervous branch. These two fissures open below, near the junction of the three super- sphenoidal canals. Two of these, which are very wide, are placed one before the other, and separated only by a slight partition. The superior of these constitutes the great sphenoidal fissure ; the other, the lower, is the foramen rotundum, and opens into the orbital hiatus. The third, very small, is situated outside the great anterior canal, opens above the optic foramen, within the bony mass surmounting the hiatus, and sometimes on the free margin of this lamina. Borders.—The superior is a little concave, and shows, in its middle, the superior extremity of the body, mammillated and articulated with the summit of the basilar process; on each side, two notches which circumscribe below the occipito-spheno-temporal hiatus (foramina lacera basis cranit). The internal notch is the narrowest, and from its affording a passage for the internal carotid artery, is called the carotid notch ; it is continued on the external face of the bone by a smooth excavation to which Rigot has given the name of carotid fossa. The external is also prolonged on the exterior surface cf the sphenoid by a short and wide fissure; it lodges the inferior maxillary nerve. Outside this is another very narrow notch, intended for the passage of the middle meningeal artery. The fibro-cartilaginous sub- stance that partly fills the occipito-spheno-temporal hiatus, transforms these notches into foramina, the first of which is named the carotid canal, the second, the foramen ovale, and the third, the foramen spinosum. The inferior border, also concave, is likewise divided into three portions, a middle and two lateral. The first is thick, and formed by the inferior extremity of the body ; it is excavated by two large cavities belonging to the sphenoidal sinus. These cavities are separated from one another by a vertical osseous plate, often perforated, which, at an early period, is fused with the perpendicular VHE HEAD, 41 lamina of the ethmoid bone, The very thin lateral portions form part of the circumference of the wings; they are notched near their union with the middle piece to assist in the formation of the orbital foramen. The two lateral borders are thin and convex in their an- terior half, as is also the contour of the wings, which are mortised in the frontal bone. For the remainder of their extent they are thick, denticulated, and bevelled at the expense of the external plate, to articulate with the squamous portion of the temporal bone. Structure.—This bone is compact on its sides, and spongy in its middle part; inferiorly, it is excavated by the sphe- noidal sinuses. Development.—lt is developed from two principal nuclei of ossification; a superior forms the subsphenoidal pro- cess and the canal of the same name, the vidian fissure, pituitary fossa, fissures of the internal face, and the most pos- terior of the great supersphenoidal canals ; the other, the inferior, forms that portion of the body hollowed by the sinuses, the lateral ale,! and the optic fossa and canals. In meeting each other, these centres form the vidian canal and the two anterivr supersphenoidal canals. They are not consolidated with each other until a very late period ; for which reason they are sometimes de- scribed as two distinct bones. M. porepion BONES OF THE HEAD aniok Tabourin has even proposed to attach parts (ose) AT BIRTH; DISARTICU- the description of the inferior sphenoid Larep aND VIEWED IN FRONT. to that of the ethmoid, because it is a, Sphenoid bone,—1, Maxillary notch; 2, united with this bone along time before Carotid notch ; 3, Groove for the passage a, &. 6% : . of the maxillary nerve; 4, Cavernous it is joined to the superior portion. muss &, Otic tomes 6 Great wines 5" i ti reat, wing ; 6. Te emporal B one. a fete Puen he the abil The temporal bones ihelose the foramen—x, Vomer.—c, Palate bone.— ¥ : : 4 D, Zygoma.—F, Superior maxilla,—8, In- cranial cavity laterally , and articulate ferior orifice of the maxillo-dental canal. with the occipital, parietal, frontal, __», Premasillary bone. sphenoidal, and the zygomatic bones; ee . also with the inferior maxilla and the hyoid bone. Each is divided into two pieces, which are never consolidated in the horse; one forms the squamous portion of the temporal bone ; the other, the tuberous portion. They will be described separately. : sa Squamors Portion—This is flattened on both sides, oval, and’ slightly incurvated like a shell, a shape to which it owes its name. It offers for study an external and an internal fage, and a circumference. 1 These wings are not analogous to f. Se portions of the sphenoid bone in Man bear- ing the same name, They are the processes of Ingrassias enormously developed. 42 THE BONES. Faces.—The external face is convex, and marked by some muscular imprints, vascular fissures, and openings which penetrate the parieto- temporal canal. It forms part of the temporal fossa, and gives origin near its middle to the zygomatic process, a long eminence which at first runs outwards, and goon curves forwards and downwards to terminate in a thin summit. The base of this eminence forms, in front, a concave surface belonging to the temporal fossa ; behind, it offers the articular surface which corresponds with the maxillary bone. The latter is composed of: 1, A condyle transversely elongated, convex above and below, and slightly concave from side to side; 2, A glenoid cavity, limited below by the condyle, above | by a mammiform eminence, the supercundyloid,} against which rests the maxillary condyle when this bone is drawn backwards; it is immediately above this eminence that the inferior orifice of the parieto-temporal canal.opens. The external ‘face of the zygomatic process is smooth and convex; the internal, concave, is also smooth, and bordered cutwards by the temporal fossa. Its anterior border is sharp and convex; the posterior, very short, is thick and roughened. Its summit is flattened from before to behind, and marked by notches on its two faces; it somewhat resembles a wedge, fixed as it is between the orbital process of the frontal bone and the zygoma; it comes in contact with the maxillary bone, and by a small portion of its anterior face, which is deprived of notches, it concurs in circumscribing the orbital cavity. In the domesticated animals, as in Man, the zygomatic process appears to arise from the surface of the bone by two roots: one, the inferior or transverse, is represented by the condyle; the other, the superior, forms a sharp crest which is continuous with the anterior border of the process, and above, joins the lateral crest of the occipital protuberance. The internal or cerebral face of the squamous portion is divided into two parts by an almost vertical channel which terminates above the super- condyloid eminence, and which, meeting a similar furrow on the parietal bone, forms the parieto-temporal canal. The superior portion is but of small extent, and of a triangular form; it articulates by a simple harmonia suture with the external face of the petrous portion. The inferior part, the widest, presents in its middle some cerebral impressions. For the re- mainder of its extent or circumference, it is cut into a wide, dentated, and lamellar bevel, which brings it in contact with the surrounding bones. Circumference.—This may be divided into two borders: one, anterior, is convex and united with the parictal and frontal bones; the other, posterior, articulates with the sphenoid in its inferior moiety, and is provided, above the level of the supra-condyloid eminence, with a deep notch which receives the external auditory canal. Superiorly, the two borders unite at the summit in a thin point which rests on the occipital bone. Structure.—The squamous portion of the temporal bone is formed of two very thin compact plates which have but little spongy tissue between them ; the latter, however, is very abundant in the body of the zygomatic process. Development.—It is developed from a single nucleus of ossification. Tuszrovs Portion.—This is one of the most interesting parts of the skeleton for study, in consequence of its containing two systems of cavities which inclose the essential organs of hearing. One of these systems is named the cavity of the tympanum or middle ear ; the other forms the internal ear, These cavities will be studied when we come to speak of the auditory ’ In Man this is represented by the inferior or vertical ramus of the upper root of the zygomatic process, THE HEAD. 43 apparatus. In the meantime, only the exterior surface and the structure and development of this portion of the temporal bone will be noticed. It is wedged between the antero-lateral border of the occipital bone, the lateral border of the parietal, and the superior part of the internal face of the temporal shell. It represents a quadrangular pyramid whose base is turned downwards and a little backwards. It will be studied successively in its four faces, a summit, and base. Faces.—The anterior face is united by harmonia suture to the parietal bone. The postericr face articulates in the same manner with the occipital bone, The eaternal face lies against the squamous portion of the bone. The internal face, slightly concave and marked by very superficial digital impressions, forms a part of the lateral wall of the cerebellar cavity. It presents the canal or internal auditory hiatus (meatus auditorius internus), a small fossa, the bottom of which is pierced by several foramina for the transmission of nerves; the largest of these is the internal orifice of the aqueductus Fallopii, a flexuous canal which passes through the bone and opens at the external surface of its base; the other foramina penetrate the cavities of the internal ear. These faces are separated from each other by so many borders or plane angles, two of which more particularly merit attention; one of these isolates the external from the posterior face, and the other separates the anterior from the internal face. The first is thick and rugged, and constitutes the mastoid crest ; it is continuous above with the lateral ridge of the occipital bone, after being united to the superior root of the zygomatic process, and terminates, near the base of the bone, by a tuberosity for muscular insertion, to which has been given the name of mastoid process. This border is traversed by a slit, the mastoid fissure,! which passes under the squamous portion and enters the parieto-temporal canal. The second is thin, and, with the superior part of the lateral border of the parietal bone, forms the crest which establishes the line of demarcation between the cerebral and cerebellar cavities of the cranium; it gives attachment to the tentorium cerebelli. Summit—This is slightly denticulated, and articulates with the occipital bone. Base.—This is very irregular, and offers: outwardly, the external auditory canal which penetrates the middle ear, and the external orifice of which has been named in veterinary anatomy the external auditory hiatus ; inwardly, a sharp crest which circumscribes the external contour of the lacerated foramen ; above, and under the mastoid process, the stylo-mastoid or pre-mastoid foramen, the external orifice of the aqueduct of Fallopius; below, the subuliform (or styloid) process for the attachment of the stylo-staphyleus (tensor palati) muscle and the Eustachian tube : this is a long, thin, and pointed process presenting, at its base and within, a canal which enters the cavity of the tympanum, and which is incompletely partitioned by a small bony plate into two parallel portions ; in the centre, the hyoid prolongation or vaginal process,” a little cylindrical eminence surrounded by a bony sheath, and the mastoid protuberance or process, a slightly salient, smooth, and round eminence hollowed internally by numerous cells, which form part of the middle ear. The several small and very remarkable canals which pass through the tuberous portion of the temporal bone, will be noticed when the nervous and arterial branches they lodge are described. 1 This ig the analogue of the mastoid canal in Man. . 2 This process is prolonged by a cartilage that unites it to the styloid bone. 44 THE BONES. Development.—The tuberous portion of the temporal bone is developed from two principal centres of ossification which are consolidated at birth, and which are often described as two distinct portions: the one as the petrous or stony portion, the other as the mastoid portion. The faces, borders, summit and inner side of the base of the bone are formed by the petrous part, which contains the cavities of the internal ear and furnishes the inner wall of the middle ear. The mastoid portion constitutes almost entirely the base of the temporal pyramid ; to it belongs the external anditory canal, the mastoid process, the sheath of the hyoid prolongation, and the styloid process; it forms the external wall and circumference of the case of the tympanum. For the tuberous portion of the temporal bone there are also two small complementary nuclei: one for the vaginal process, whose base is united to the petrous portion, and another forming the ring of the tympanum. Structure—The petrous portion is the hardest mass of bone in the skeleton, and scarcely contains any spongy tissue, except at the centre of the mastoid process ; in the mastoid portion it may be said not to exist. In the other domesticated animals, the tuberous portion of the temporal bone is always consolidated with the squamous, and the summit of the zygomatic process only articulates with the malar bone. BONES OF THE FACE. The face is much more extensive than the cranium in the majority of the domesticated animals, and is composed of two jaws, a bony apparatus that serves as a support to the passive organs of mastication—the teeth. The superior or anterior jaw, traversed in its entire length by the nasal cavities, is formed by nineteen wide bones, only one of which, the vomer, is a single bone ; the. pairs are: the superior and intermawillaries (or premawillaries), the palate, plerygoid, zygomatic, lachrymal, nasal, and superior and inferior turbinated bones. Of these only four, the maxillaries, are intended for the implantution, of the teeth; the others form the union between the cranium and the superior maxilla, or concur in the formation of the nasal cavities. The lower jaw has for its base a single bone, the inferior maxilla or mamillary bone. 1. Great Supermawilla, or Superior Mawillary Bone. This bone, the most extensive in the upper jaw, is situated on the side of the face, ard is bordered above by the frontal, palate, zygomatic, and lachrymal bones; below, by the premaxillary bones ; in front, by the nasal bone; behind and within, by that of the opposite side. It is elongated vertically, is irregularly triangular, and exhibits two faces, two borders, and two eatremities. Faces.—The external face, which is more convex in the young than the old animal, presents: 1, On the level of the fourth and fifth molar teeth, a vertically elongated ridge which is continued above with the inferior border of the zygomatic bone; this is the supermaaillary spine ; 2, The inferior orifice of the supermaaillo-dental canal, or infra-orbital foramen. The internal face concurs in forming the external parietes of the nasal cavities. We observe, above and in front, a deep, wide, and diverticu- lated excavation, forming part of the maxillary sinus; above and behind, a surface roughened by fine lamelle and dentations to correspond with the palate bone, and traversed from above to below by a fissure which forms, in uniting with a similar fissure in the latter bone, the palatine canal. For the remainder of its extent it is unequally smooth, covered by the membrane THE HEAD. 45 of the nose, and divided into two surfaces by a slightly vertical and sinuous crest that affords attachment to the maxillary turbinated bone: the anterior surface, which responds to the middle meatus of the nasal fossa, shows the lower orifice of the osseous lachrymal canal continued by a fissure to the lower extremity of the bone ; the posterior surface belongs to the inferior meatus. This face presents, near its inferior border, a large vertical apophysis, the palatine process, which offers an anterior slightly concave face, forming the ° floor of the nasal fosse@; a posterior face, furrowed by small fissures, perforated by fine openings, and traversed along its length by a somewhat wide groove, the palatine fissure, which commences above at the lower orifice of the palatine canal. The internal border of this process articulates with the analogue of the palatine process of the opposite side. Borders.—The anterior, thin and convex, is divided into two parts: an inferior, which is mortised to receive the external border of the nasal bone and the external process of the premaxillary ; and a superior, cut in a wide bevel at the expense of the external plate, to respond to tle lachrymal and zygomatic bones. The external border is very thick and hollowed into six large quadrilateral cavities, named alveoli, in which are implanted the molar teeth. Above the last alveolus it forms a rugged eminence designated the alveolar tuberosity ; below the first it becomes thin and sharp, and constitutes part of the interdental space which separates the molar from the incisor teeth. Extremities —The superior is the thickest, and represents a smooth rounded protuberance, into the interior of which the maxillary sinus is prolonged. Above and within this eminence, is a wide and deep excavation, in the formation of which the palate bones participate. This is the maxillary hiatus, situated directly opposite the orbital hiatus. At the bottom of this cavity is seen the nasal foramen, as well as the upper orifice of the supermaxillo-dental and the palatine canals. The nasal foramen belongs to the palate bone and enters the nasal cavity. The super- maxillo-dental or infra-orbital canal traverses the maxillary sinus in passing above the roots of the molar teeth, and terminates by two branches: one, short and wide, which opens on the external surface of the bone, on a level with the third molar; the other, very narrow, continues the course of the canal in the thickness of the bone, and is prolonged by several small very fine branches into the premaxillary bone. The palatine canal, channeled between the supermaxillary and the palate bone, extends from the maxillary hiatus to the palatine fissure. The inferior eatremity presents a cavity which forms the alveolus of the tusk by uniting with a similar space in the premaxillary bone. Structure and development.—This bone is developed from a single nucleus, and is the more spongy, particularly towards the alveolar border and the superior extremity, as the animal is young. 2. Premaxillary, Intermawillary, Anterior Mawillary or Incisive Bone. This bone occupies the inferior extremity of the head, and is composed of a thick prismatic portion, lengthened superiorly by two long processes. Thick portion or base.—This presents a solid mass with three faces: an external or labial, smooth and convex; an internal, denticulated for union with the opposite bone, and traversed from before to behind by an inflexed fissure, which forms, with an analogous one in the other premaxillary, the incisive canal or foramen ; the third or posterior, also called the buceal, is slighty concave, and shows the continuation of the palatine fissure, which 46 THE BONES. opens into the incisive foramen. These three faces are separated by as many borders: two internal, limiting before and behind the corresponding face; and an external, separating the labial from the buccal face. The latter only merits notice; it is very thick, and is divided into two parts: an inferior, which describes a curved line with the concavity upwards, and is hollowed by three alveoli to receive the incisor teeth; another, the superior, is straight, vertical, and somewhat sharp, and forms a part of the dental interspace. It is limited above, near the base of the external process, by a cavity for the formation of the alveolus of the tusk. Processes.—These are distinguished as ew- Fig. 21. ternal and internal. The first, the longest and strongest, is flattened on both sides; its ex- ternal face is smooth and continued with that of the thick portion of the bone; its internal face is covered by the mucous membrane of the nose; the anterior border is smooth and rounded; the posterior, denticulated to re- spond to the supermaxillary bone, is in con- tact with the external border of the base ; its summit is thin, and is insinuated between the latter and the nasal bone. The internal pro- cess, the smallest, is flattened from before to behind, and forms a very thin tongue of bone, separated from the other portions by a nar- row and very deep notch named the incisive opening or cleft. Its inferior face constitutes a small portion of the floor of the nasal fosse ; the posterior, continuous with the same face of the principal mass of the bone, forms part of the palatine roof; its external border cir- cumscribes, inwardly, the incisive opening ; the internal is united by dentated suture with the opposite bone. Structure and development.—It is a spongy bone, developed from a single nucleus. 3. Palate Bones. The palate bones are situated between the supermaxillaries, at the margin of the guttural opening of the nasal cavities, and are articu- POSTERIOR ASPECT or Horsr’s lated with the sphenoid, ethmoid, vomer, SKULL, frontal, and pterygoid bones. Elongated from 1, Occipital protuberance; 2, #bove to below, flattened laterally, and curved Foramen magnum; 3, 3, Oc- cipital condyles; 4, 4, Styloid processes; 5, 5, Petrous bone; 6, Basilar process; 7, Pterygoid fissure of the sphenoid bone; 8, Foramen lacerum; 9, 9, Supra-condyloid, or anterior mastoid process; 10, 10, Articular eminence, or temporal condyle; 11, Body ot sphenoid bone; 12, Pterygoid process; 13, Ethmoid bone; 14, Temporal bone and sphe- noidal suture; 15, Lachrymal bone; 16, Vomer; 17, Malar bofie; 18, Maxillary tube- rosity; 19, Posterior, or guttural opening of the nose; 20, Palate bone; 21, Palatine styloid process; 22, Palato-maxillary foramen; 23, Palatine process of superior maxil- lary bone with suture; 24, Ditto of premaxillary bone; 25, Premaxillary bone; 26, Upper incisor teeth; 27, Point of junction of the premaxillary with the superior maxil- lary bone; 28, Upper molar teeth—young mouth. THE HEAD. 47 towards each other at their inferior extremity, which is flattened from before to behind, these bones, though irregular in shape, offer for study two faces, two borders, and two extremities. Faces.—The eaternal face of the palate bone is divided into three frac- tions, ® superior, or orbital, an inferior, or palatine, and a middle, or articular. The first is smooth and slightly excavated, and participates in the forma- tion of the maxillary hiatus ; it shows a small fissure, the staphyloid, which reaches the palatine fraction in passing between the posterior border of the bone and the alveolar tuberosity. The second is not extensive, and looks backwards in consequence of the antero-posterior flattening which the bone presents at its inferior extremity; it forms part of the roof of the palate. The third presents a lamellar and denticulated ‘surface which corresponds to a similar face on the supermaxillary bone, and is channeled from above to below by the internal fissure of the palatine canal. The internal face, smooth and concave, forms part of the external wall and the floor of the nasal fossa. Borders.—The anterior is indented, near its superior third, by a deep notch, which is often converted into a foramen, the nasal. Below this notch the bone is thin and denticulated for union with the supermaxillary bone; above, its two plates separate widely from one another, giving rise to a very spacious cavity which forms part of the sphenoid sinus. The posterior border presents, above, a rugged crest called the palatine, flattened from side to side, bent outwards, and bordered at its base and inwards by a very narrow synarthrodial surface which responds to the pterygoid bone. It is smooth and concave in its inferior half, and forms, with that of the opposite side, a parabolic arch which circumscribes, below and at the side, the double guttural orifice of the nasal cavities. Extremities —The superior, flattened on both sides, is bevelled on the external side to articulate with the subsphenoidal process. The inferior, flattened from before to behind, is curved inwards and united by simple suture with that of the opposite bone. Structure and development.—This is a very compact bone, developed from a single centre of ossification. 4, Pterygoid Bones A small and very narrow bone, elongated from above to below, flattened on both sides, and situated on the inner aspect of the subsphenoidal process, but external to the vomer. Its eaternal face is in contact with the palate and sphenoid bones ; the internal is smooth and covered by the pharyngeal mucous membrane. Its superior extremity is tapering, and concurs in forming the vidian canal ; the inferior is thickened into a small pointed process (the hamular process), whose apex, directed backwards, offers outwardly a groove which serves as a pulley to the tendon of the tensor palati. This bone is composed entirely of compact tissue, and is developed from a single centre of ossification. 5. Zygomatic Bone. This bone, also designated the malar and jugal bone, is elongated from above to below, flattened on both sides, and irregularly triangular in shape; it is situated on the side of the face, and articulates with the supermaxillary, 1 This bone is the representative of the internal wing of the pterygoid process in Man, 48 THE BONES. lachrymal, and temporal bones. It is described as having two faces, two borders, a base, and a summit. ; Faces.—The external face comprises two portions separated from each other by a semicircular ledge that extends from the summit to the middle of the anterior border of the bone, and concurs to form the outer margin of the orbit. The anterior portion, smooth and concave, belongs to the orbital cavity. The posterior, more extensive, is also smooth and slightly convex, The internal face is excavated in its central part, which corresponds to the maxillary sinus. On its margin it shows dentations and lamelle for articu- lation with the supermaxillary bone. Borders.—The anterior, thin aud denticulated, is joined to the lachrymal bone. The posterior, or masseteric border, is thicker, and constitutes a roughened crest, the zygomatic ridge, which is continued above with the posterior border of the process of the same name, and below with the maxillary spine.! Base and summit.—The base, very thin, is united to the supermaxillary bone. The summit, flattened from before to behind and bevelled on its anterior face, joins the zygomatic process, and forms with it the jugal bridge or zygomatic arch. Structure and development.—This bone is rather spongy in its upper part, and is developed from a single nucleus of ossification. 6. Lachrymal Bone. A small, thin, and very light bone, bent on itself at a right angle, it is situ- ated beneath the orbit, which it aids in forming, and is wedged between the frontal, nasal, supermaxillary, and zygomatic bones. It is studied on its external and internal faces and circumference. Faces.—The external is divided into two regions, superior and inferior, by a curved crest which forms part of the orbital margin, and is provided with notches, which are variable in their form and number. The superior region, named the orbital, because of its situation in the orbit, is slightly concave and smooth. It presents, near the orbital margin, the orifice of the lachrymal duct, which traverses the maxillary sinus and opens on the internal face of the supermaxillary bone, where it is continued by a fissure ; behind this is the lachrymal fossa. The inferior or facial region is slightly bulging, and provided sometimes with a tubercle of insertion, the lachrymal tubercle. The internal face is employed, for the whole of its extent, in the formation of the walls of the maxillary and frontal sinuses; it exhibits a cylindrical prominence produced by the bony tube of the lachrymal duct. Circumference—This is very irregular and denticulated to respond to the neighbouring bones. Structure and development.—This bone is entirely compact, and is developed from a single nucleus of ossification. 7. Nasal Bones. Situated on the anterior aspect of the head, these bones articulate with each other in the median line, and are fixed between the frontal, lachrymal, and supermaxillary bones; they are triangular in shape, elongated from above to below, flattened from before to behind, and offer for study two faces, two borders, a base, and a summit. Faces.—The external or anterior face, larger above than below, is convex > The designation of zygomatic crest ig often given to these three parts collectively. THE HEAD. from side to side and almost smooth. The posterior, internal, or nasal face exhibits a ver- tical crest passing along the external border of the bone, which gives attachment to the nated portion of the ethmoid; at its supe- rior extremity this crest bifurcates, and between its two branches shows a concave surface which forms part of the frontal sinus. For the remainder of its extent the internal face is smooth, and covered by the mucous membrane of the nasal fossa; it is also excavated into a channel to form the superior meatus of this cavity. Borders.—The external border is very thin in its upper two-thirds, and articulates with the lachrymal bone, the anterior border of the supermaxillary, and the upper extremity of the premaxillary bones. In its lower third it becomes isolated from the latter bone, in forming with the anterior border of its large process a very acute re-entering angle whose opening looks downwards. The internal border s denticulated to correspond with the opposite one. Base and Summit.—The base occupies the superior extremity of the bone; it describes a curved line with the convexity above, and in uniting on the median line with that of the opposite bone, forms a notch similar to that of the heart figured on playing cards; it is bevelled at the expense of the internal plate to articulate with the frontal bone. The summit of the two nasal bones, which is pointed, constitutes the nasal prolongation: the name given to a single triangular process which comprises all that portion of the nasal bones separated from the premaxillaries by the re- entering angle before mentioned. Structure and development.-—Almost entirely compact in structure, it is developed from a single centre. 8. Turbinated Bones. The iturbinated bones, two on each side, represent two irregular bony columns, wider above than below, compressed laterally, hol- lowed internally, and lying vertically side by side on the external wall of the nasal fossa, which they divide into three meatuses or pas- sages. They are distinguished into anterior and posterior turbinated bones. The anterior or superior, also named the 49 ANTERO-POSTERIOR AND VERTICAL SECTION OF THE HORSE’S HEAD. 1, Condyloid foramen; 2, Parietal protuberance; 3, Internal audi- tory hiatus; 4, Cerebral cavity 5 5, Cerebellar cavity; 6, Supe- rior border of the perpendicular plate of the ethmoid bone (crista- galli process); 7, Ethmoidal volutes—nasal face; 8, Vestiges of the right frontal sinus, 9, Ditto of the sphenoidal sinus; 10, Pterygoid process; 11, Eth- moidal turbinated bone; 12, Maxillary turbinated bone; 13, Crest of the supermaxillary bone to which the latter is fixed ; 14, Vomer.—a, Orifice of com- munication between the nasal cavity and the sinus, 50 Fig. 23. LONGITUDINAL AND TRANSVERSE SEC™ TION OF THE HORSE’S HEAD, SHOW- ING THE FLOOR OF THE CRANIAL AND NASAL CAVITIES, WITH THE MAXILLARY SINUSES. Condyloid foramen; 2, Section of the parieto-temporal canal; 3, Occipito- spheno-temporal hiatus; 4, Carotid notch; 4’, Maxillary notch.—«, Supermaxillary fissure; 6, Cavernous fissure; 5, Origin of the supersphe- noidal canals.—c, Sella turcica; 6, Optic fossa; 7, Portion of the crista-galli process; 8, Cribriform plate of the ethmoid bone; 9, Per- pendicular plate of the same bone; 10, 10, Its lateral masses; 11, Inte- rior of the great ethmoidal cell; 12, 12, Bottom of the maxillary sinuses communicating with the sphenoidal sinuses; 13, THE BONES. ethmoidal, is formed by a very thin plate of compact tissue, fragile and like papyrus, fixed by its anterior border to the internal crest of the nasal bone, and rolled on itself, from befvre to behind, in the same manner as the cells of the ethmoid bone, Above, it is confounded with the last- named bone, of which it is only, properly speaking, the most anterior volute. At its inferior extremity, it is prolonged by a fibro-cartilaginous framework to the ex- ternal orifice of the nose. Its internal cavity is partitioned by a transverse plate into two portions: the superior compartment forms part of the frontal sinus; the inferior is subdivided by other small lamelle into a variable number of cells which communicate with the nasal cavity. This bone, developed from a single nucleus, is ossified at the same time, and in the same manner, as the ethmoidal cells. Before birth, it is already intimately consolidated with the nasal bone. The posterior, inferior, or mazillary turbinated bone resembles the first, except in some particulars. Thus, its bony or proper portion is not so long or volu- minous, while its cartilaginous part is, on the contrary, more developed. It is at- tached, by its posterior border, to the ver- tical and sinuous crest of the super- maxillary bone, and is rolled from behind to before, or in an inverse direction to the other. It has no connection with the ethmoid, and its superior cavity forms part of the inferior maxillary sinus. It is late in becoming ossified, and is scarcely united in a definife manner to the max- rik bone until the horse is about a year old. ; The meatuses are distinguished into anterior or superior, middle, and posterior or inferior, The first passes along the front of the ethmoidal turbinated bone; the second separates the two turbinated bones, and presents, near its superior extremity, the opening communicating between the sinuses and the nasal cavi- Supe- rior maxillary sinus; 14, Inferior maxillary sinus; 14’, Superior compartment of the max- illary turbinated bone, forming part of the latter sinus; 15, Section of the supermaxillo- dental canal; 16, Channel of the vomer; 17, Internal process, or point of the premax- illary bone, THE HEAD. 51 ties.) The third is situated behind the maxillar i is confounded with the floor of the nasal fossa. epee eee The turbinated bones are essentially destined to furnish the membrane of the nose with a vast surface of development. This membrane, indecd covers their entire superficies, and even penetrates the anfractuous cells of their lower compartment. 9. Vomer. ; This, a single bone, elongated from above to below, flattened on both sides, and extending on the median line from the body of the sphenoid to the premaxillary bone, offers for study two lateral faces, two borders, and two extremities. The faces are smooth, plane, and covered by the nasal membrane. The anterior border is channeled for the whole of its length by a deep groove which receives the posterior border of the cartilaginous septum of the nose. The posterior border is sharp and smooth in its upper half, which separates the two guttural openings of the nasal cavities: it is thick and slightly denticulated for the remainder of its extent, and rests on the median suture resulting from the union of the two supermaxillary bones. The superior extremity is provided, in its middle, with a notch which divides it into two lateral prolongations shaped like a cat’s ears; it articulates with the inferior sphenoid, ethmoid, palate, and pterygoid bones. The inferior extremity rests on the prolongations of the incisive bones. This bone is entirely compact, and is developed from one centre of ossification. 10. Inferior Maxillary Bone. The mazillary bone is not consolidated with any of the preceding bones, and is only united to two of them, the temporals, by diarthrodial articula- tion. It is a considerable bone, situated behind the upper jaw, and composed of two symmetrical branches, which are flattened on both sides, wider above than below, curved férwards in their upper third, joined at their lower extremities, and separated superiorly so as to leave a wide gap between them, like the letter V in shape, called the intramasillary space. Each offers for study two faces, two borders, and two extremities. Faces.—The external face of the maxillary branches is smooth and rounded in its inferior two-thirds, and transformed superiorly into a rugged surface, in which is implanted the fibres of the masseter muscle, The internal face presents, in the corresponding point, an excavated surface on which is remarked the superior orifice of the mawillo-dental canal, a long channel which descends between the two plates of the branch, passing under the roots of the molar teeth, and insensibly disappearing in the body of the bone after being widely opened externally by the mental (or anterior masillary) foramen. In its inferior two-thirds, the internal face is smooth, nearly plane, and shows nothing very remarkable. Near the alveolar border there is a slightly-projecting line—the myloid ridge ; and quite below, or rather at the very summit of the re-entering angle formed by the separation of the branches, there is a slight rugged ee confounded with that of the i ch, and named the genial surface. ne anterior, ma named the alveolar border, exhibits for study a straight or inferior, and a curved or superior portion. The first is hollowed by six alveoli to receive the inferior molar teeth. 1 The two turbinated bones, in being applied against the excavation on the inner face of the supermaxillary, almost entirely close it, only leaving between them a vertical slit which constitutes the opening mentioned above. 52 THE BONES. The second, thinner, concave, and rugged, serves for muscular insertion. The posterior border is also divided into straight and curved portions. The latter is convex, thick, rugged, and margined on each side by an uneven lip; the first is regularly rectilincar, so that all its points rest at the same time on a horizontal plane; it is thick and rounded in the young animal, but becomes sharp with age; an oblique and transverse fissure—the mawillary —separates it from the curved part. ‘The union of these two portions forms the angle of the jaw. : Extremities—The superior extremity has two eminences: a condyle, and a long non-articular process named the coronoid process. The condyle is elongated transversely, and convex in its two diameters; it responds, through the medium of a fibro-cartilaginous dise, to the articular surface of the zygo- matic process. The coronoid process is situated in front of the condyle, from which it is separated by a division called the sigmoid or corono-condyloid notch ; it is fattened on both sides, and curved backwards and slightly inwards. Fig. 24, INFERIOR MAXILLA. 1, Mental foramen; 1’, Superior orifice of the maxillo-dental canal; 2, Surtace ot implantation for the masseter muscle; 3, Myloid ridge, 4, Coronoid process; 5, Condyle. From tke union of the branches of the maxillary bone at their inferior extremity results a single piece, flattened before and behind, and widened like a spatula, which has been designated the body of the bone. This merits a special description. Its form allows us to divide it into an anterior or buccal face, a posterior or labial face, and a circumference. The anterior face is smooth and concave, is lined by the buccal mucous membrane, and supports the free extremity of the tongue. The posterior face is convex, more extensive than the preceding, and continuous with the external face of the branches; it presents: 1, On the median line, a slight crest or small groove, traces of its being originally separated into two pieces; 2, On the sides and above, the mental foramen, the inferior orifice of the maxillo-dental canal. On a level with this foramen, the bone very markedly contracts to form the neck. The circumference describes a parabolic curve, the concavity being uppermost, and joins, by its extremities, the anterior border of each branch. It is excavated in its middle part by the six alveoli for the lodgmen* of the THE HEAD. 53 inferior incisors, and behind these, in male animals only, there i additional alveolus for the tusk. The portion included on soak side borers the last incisor and first molar, forms a more or less sharp ridge, which constitutes the inferior interdental space or bars. : Structure and development.—Formed, like all the flat bones, by two compact plates separated by spongy tissue, the inferior maxilla is developed from two centres of ossification, which correspond to each branch, and which coalesce some time after birth. : 11.—The Hyoid Bone. The hyotd bone constitutes a small and special bony apparatus which serves to support the tongue, as well as the larynx and pharynx; its description is placed immediately after that of the bones of the head because of its connection with that region, it being situated between the two branches of the supermaxillary bone, and suspended to the base of the cra- nium in an oblique direction from above to below, and from before to behind. This apparatus is composed of seven distinct pieces, arranged in three series: a middle, constituted by a single bone, and named the body; two lateral, forming two quasi-parallel branches, to the extremities of which the body is articulated. Body.—The body of the hyoid resembles a fork with two prongs. It presents: 1, A middle part flattened above and below, and consequently pro- vided with a superior and an inferior face ; 2, A single and long prolongation flattened on both sides, which is de- tached from the middle part, and directed forward and downward to plunge into the muscular tissue of the tongue: this is the anterior pate are app endia of the hyoideal body 3 1, 1, Superior extremity of the styloid bones, 2, Angle 3, Two lateral cornua, thyroid described by their posterior border; 3, 3, Styloid cornua, or great cornua, pro- bones; 4, 4, Extremities of the thyroid cornua; 5, jecting backwards and up- Articular surface of the body corresponding with the wards, articulating by their — $73/!_ Pranches; 6 Se ee ee extremities with the thyroid a Sa Ce asta a cartilage of the larynx, and offering, at their point of union with the middle part, two convex diarthrodial facets looking upwards, and corre- sponding with the styloid cornua. The body of the hyoid bone is developed by three centres of ossification, a middle, and two lateral for the cornua. Branches.—The three pieces composing these are articulated end to end, by means of a cartilaginous substance that joins them together; they are of very unequal dimensions. The first, which is in relation with the body, is of medium size, and is named the styloid cornu, small cornu, or small branch. The second, termed the stylotd nucleus, is the smallest. The third, the largest, constitutes the styloid process, or bone, or great branch. 1. The styloid cornu is a small cylindrical piece bearing a concave diarthrodial surface on its inferior extremity to unite it to the body ; it is very spongy, and is developed from two ossifying centres, one of which, the epiphysary, is for the inferior extremity. a: : = 2. The styloid nucleus, which is often absent, is imbedded in the uniting cartilaginous substance. Fig. 25, St THE BONES. 3. The styloid bone, or great hyoideal branch, is long, thin, flattened on both sides, and directed obliquely from above to below, and before to behind ; it presents two faces, two borders, and two extremities. The faces —an external and internal—are marked by some few imprints. The anterior border is sharp and slightly concave in its upper third. The posterior border is thicker, and is divided into two portions: a superior or horizontal, which is very short, and an inferior or vertical, much more extensive. The angle they form at their point of junction presents a salient, and more or less roughened, tuberosity. The superior extremity is united to the hyoideal prolongation of the temporal bone by means of a cylindrical fibro-cartilage. By its inferior extremity, the styloid bone is united either to the styloid nucleus or the styloid cornu, forming a sharp elbow directed forwards. The. styloid bone, developed from a single centre of ossification, is almost entirely formed of compact tissue. OF THE HEAD IN GENERAL. From the union of all the bones which constitute the cranium and face results a quadrangular pyramid, whose summit is inverted, which it is necessary to study as a whole. We will pass in review, successively, its four faces, its base, and its summit. Anterior Face.—The anterior aspect of the head has the parietal, frontal, and nasal bones for its base. Superiorly, it inclines backwards and. offers, on each side of the parietal ridges, two bulging surfaces which form part of the temporal fosse. For the remainder of its extent, it presents a plane surface which forms the base of the forehead and the middle portion of the face. Wide above, this surface gradually tapers to the extremity of the nasal spine. In well-formed animals, it is as straight and wide as possible. Posterior Face.-—This face, which is extremely irregular, presents : above, the basilar process, the lacerated foramina, and the base of the tuberous portion of the temporal bones; then the intramaxillary space, and, at the bottom of this, the body of the sphenoid bone, vidian fissure, superior orifice of the subsphenoidal canal, sphenoidal process, palatine ridges, pterygoid bones, guttural openings of the nasal cavities separated from one another by the posterior border of the vomer, roof of the palate, incisive openings, and the incisive foramen. Lateral Faces.—These exhibit : behind, the external face of the maxillary branches ; before, a surface more or less convex, though sometimes hollow in old animals, presenting at its middle the inferior orifice of the maxillo- dental canal, and forming the base of the lateral parts of the face; above, the zygomatic ridge and arch, the orbit, and the temporal fossa. These two cavities, in the formation of which many bones participate, have been hitherto merely indicated ; this is the place for giving them a more detailed description. _ The orbit or orbital cavity is irregularly circular in outline, and circumscribed by the orbital process of the frontal bone, the lachrymal and malar bones, and the summit of the zygomatic process. At the bottom, which shows the maxillary and orbital hiatus, it is confounded, in the skeleton, with the temporal fossa.' It lodges the globe of the eye and the muscles which move it. Some organs, accessory to the visual apparatus, 1 A fibrous membrane, the ocular sheath, isolates it from the temporal fossa in the majority of mammiferous animals. Only in Man and the quadrumana has the orbital cavity complete bony walls. ‘ THE HEAD, 55 such as the ]: icti oe a gland and the membrana nictitans, are also contained The temporal fossa surmounts the orbit, and is i from it by the orbital arch (or process). Oval = shapes Tyee te ey an above to below, and from within outwards, on the sides of the fe eae temporal fossa is limited, within, by the parietal ridge, and o vi gant c the anterior border of the longitudinal root of the z 0 ti abo s toler the temporal muscle. : Peeruan eae ee ase or superior extremity of the head.—This pre: ipi tuberance, cervical tuberosity, occipital foramen, menos ie eae a - styloid processes of the occipital bone, stylo-condyloid notches, and the aoe dyles. Ona lower plane, and behind, the curved portion of "the osteri border of the maxillary bone is remarked. cea Summit.—Formed by the premaxillary bones and the body of the super- Fig. 26, LATERAL VIEW OF THE HORSE’S SKULL. 1, Premaxillary bone; 2, Upper incisors; 3, Upper canine teeth; 4, Superior maxillary bone; 5, Infraorbital foramen; 6, Superior maxillary spine; 7, Nasal bones; 8, Lachrymal bone; 9, Orbital cavity ; 10, Lachrymal fossa; 11, Malar bone; 12, Upper molar teeth; 13, Frontal bone, 15, Zygomatic process, or arch; 16, Parietal bone; 17, Occipital protuberance; 18, Occipital crest; 19, Occipital condyles; 20, Styloid processes; 21, Petrous bone; 22, Basilar process; 23, Condyle of inferior maxilla; 24, Parietal crest ; 25, Inferior maxilla; 26, Inferior molars; 27, Anterior maxillary foramen; 28, Inferior canine teeth; 29, Inferior incisor teeth. maxilla, the summit supports the incisor teeth, and presents a tuberosity more or less rounded, according to the age of the animal. In front, it is surmounted by the external opening of the nasal cavities; this opening, which is comprised between the external process of the premaxillary bones and the nasal spine, is divided in the fresh state into two orifices which constitute the nostrils. ; : Internally, the head contains the nasal fosse and the cranial cavity. These will be described when the apparatus belonging to them is noticed. (See the respiratory and nervous apparatus). DIFFERENTIAL CHARACTERS OF THE HEAD IN OTHER THAN SOLIPED ANIMALS. A. Heap or THE Ox, SHEEP, AND GoAT.—l. Ocetpital bone.—The occipital bone in these animals docs not show any anterior elbow. The cervical tuberosity, or occipital 56 THE BONES. i i i i the superior curved lines; in the tuberance is obtuse, and gives rise on each side to : Bheep slice curved lines are very salient and occupy the summit of the head. oi The styloid processes are short and much bent inwards. The basilar process, wide, short, and Thick has a groove in the middle of its external face ; this groove is sometimes it in the Sheep and Goat. ae cone ean are double, sometimes triple; the superior foramen does not ass directly into the cranium, but goes to a vast conduit that opens behind on the lateral Le in of the occipital foramen, and which terminates in front by two orifices, one calgae the parieto-temporal canal, the other opening on the external surface of the bone. The foramen lacerum is divided into an anterior and posterior foramen by the ol ‘tion of the temporal bone. ; Ee kee parietal bone in the Ox does not occupy the anterior aspect Fig. 27. = Ss al | GA E \ NU | yi \ WN ae | i i Ox’s HEAD; ANTERIOR FACE. 1, Mastoid process; 2, Superciliary, or supra-orbital foramen; 3, Zygoma; 4, Lachrymal bone; 5, Maxillary spines 6, Inferior orifice of the supermaxillo-dental canal. of the head, but concurs with the occipital to form the base of the neck. It represents a very narrow osseous plate, elongated transversely, and curved at its two extremities, -which descends into the temporal fosse to rest upon the sphenoid bone. There are no parietal ridges. The internal protuberance is only marked by a slight elevation of the internal plate ; for the most part it belongs to the occipital bone. The parietal bone of the Ox is developed from three centres of ossification, and the middle nucleus is even primerily divided into lateral halves ; but these centres are consolidated with each other at an early period, as well as with the anterior portion of the occipital. It does not aid in the formation of the parieto-temporal canal, and is excavated internally by cavities which communicate with the frontal sinuses, __ The parietal bone of the Sheep and Goat is relatively much larger than that of the Ox. It participates in the formation of the parieto-temporal canal, and has no sinuses. 3. Frontal bone.—In ruminants, the frontal bone does not respond to the temporal and palate bones. Inthe Ox, this bone is extremely developed, by itself occupying the anterior half of the THE HEAD, 57 face. It is particularly distinguished by:—1, Its great thickness. 2, The osseous conical cores which support the horns. These eminences, more or less loug and curved, very rugged, perforated by foramina, and grooved by small vascular channels, are ® detached outwards from each side of the bone, near the summit of the head. The processes which form the orbital arches rest by their summits on the zygomatic bone. ‘The supra-orbital foramen is transformed into a veritable and frequently multiple canal; its anterior orifice opens into a vasculo-nervous groove, which ascends towards the base of the horns, and descends to near the lower border of the bone. Between this groove and the base of the orbital arch is the frontal boss. The orbital foramen entirely belongs to this bone. The inferior border is deeply notched in its middle to receive the nasal bones, the frontal sinuses are prolunged into the horn-cores, the parietal bone, and even into the occipital bone. In the Sheep and Goat, the frontal bone is relatively less extensive and strong than in the Ox; it does not ascend to the summit of the head, and the frontal sinuses are not prolonged beyond its superior border. 4, Kthmoid bone.—In ruminants, the great ethmoidal cell is enor- Fig. 28, mously developed, and looks like a third turbinated bone prolonged be- tween the usual two; it has been named the olfactory antrum. The ethmoid bone is closely im- prisoned between the adjacent bones, in consequence of the slight develop- ment of the sinuses around it. This character otherwise belongs to all the domesticated animals, except soli- peds. 5. Sphenoid bone.—In the Oz, the subsphenoidal or pterygoid pro- cesses are large and thin. The sub- sphenoidal canal is absent. The sella turcica is deep, and the bony projection separating it from the basilar process is very high. The three suprasphenoidal canals are converted into a single, but wide one. There are no notches in the superior border for the passage of the internal carotid and spheno- spinous arteries, That for the in- ferior maxillary nerve is converted into a canal—the oval foramen. In the Sheep, the osseous promi- nence that limits the pituitary fossa posteriorly forms a lamina cury- ing forwards and prolonged at its ex- tremities into two points, which constitute the posterior elinoid pro- cesses. 6. Temporal bone—In the Oz, RAM’S HEAD; ANTERIOR FACE. Sheep, and Goat,the tuberous portion 4, Occipital bone; 2, Parietal bone; 3, Core of right of the temporal bone is always con- _—fyontal bone; 4, The left core covered by its horn; solidated with thesquamous portion, 5, Superciliary foramen; 5’, Channel descending and the summit of the zygomatic from it; 6, Lachrymal bone; 7, Zygoma; 8, Nasal process only articulates with the bone; 9, Supermaxillary bone; 10, Premaxillary malar bone. bone; 10’, Its internal process; 11, Incisive open- In the Ox, the condyle of the img. zygomatic process is very wide and j ; convex in every sense. The parieto-temporal canal is very large and entirely excavated in the temporal bone; its superior or internal extremity opens above the petrous portion in an excavation which represents the lateral cavity of the parietal protuberance in the Horse: at its inferior extremity it always shows several orifices. ° The mastoid process is very salient, and belongs to the squamous portion. The mastoid crest is confounded with the upper root of the zygomatic process; inferiorly, it 58 THE BONES. th toid process, and is prolonged to the mastoid protuberance. The latter a ee ctlviainees The salalifeutd prooond is larger and stronger than in the Horse; i stoid fissure. 2 Fis ' eae en ned Goat, the mastoid process is scarcely distinct from the crest; and the mastoid portion of the bone is only at a late period consolidated with the petrous portion. : Ox’s HEAD; POSTERIOR FACE. A, Parietal bone.—1, Occipital foramen; 2, Occipital condyle; 3, Styloid process of that bone; 4, Condyloid foramina; 5, Mastoid process; 6, Mastoid protuber- ance; 7, Subuliform (temporal) process; 8, Hyoideal sheath; 9, Stylo-mastoid foramen; 10, External auditory hiatus; 11, Inferior orifice of the parieto-tem- poral canal; 12, Temporal condyle; 13, Posterior foramen lacerum; 14, Oval foramen; 17, Subsphenoidal process; 18, Orbital hiatus; 19, Optic foramen.— B, Frontal bone.—20, Superciliary foramen; 21, Orbital foramen; 22, Lachrymal protuberance.—c, Zygoma.—23, Pterygoid bone.—p, Palate bone.—24, Nasal fora- men; 25, Inferior orifice of the palatine canal.—r, Supermaxillary bone.—26, Maxillary spine-—G, Premaxillary bone.—27, Its internal process; 28, External process; 29, Incisive openings. 7. Supermaxillary bone.—In the Ox, Sheep, and Goat, the maxillary spine does not directly join the zygomatic crest a curved line, whose concavity is posterior, effects the union between these two parts. The inferior orifice of the supermaxillo-dental canal or infraorbital foramen is pierced above the first molar tooth. There is no fissure for the formation of the palatine canal. The cavity of the sinus is more spacious than in the Horse, and is prolonged (in the Ox only) between the two laming of the palatine roof. There is no alveolus for the tusk. 8. Premaxillary bone—The inferior or principal portion of this bone is flattened before THE HEAD, and behind. and deprived of aveoli in its external border; neither is there any incisive foramen. It is rarely consolidated with the adjacent bones, and is never, in the smaller ruminants, articu- lated with the nasal bone. 9. Palate bone.—This bone is very developed in the Ox, and noticeable tor the considerable extent of the palatine portion of its external sur- face. The palatine canal is entirely channeled out in its substunce. The palatine crest, very thin and elevated, is formed altogether by the posterior border of the palate bone, the ptery- goid, and the subsphenoidal process. There is no excavation for the sphenoidal sinuses; but, instead, all that part of the bone which enters into the roof of the palate is hollowed by irre- gular cavities which communicate with the max- illary sinus of the same side, The nasal foramen is very wide. In the Sheep and Goat, the maxil- lary sinuses do not extend to them. 10. Pterygoid bone.—The pterygoid of the Ow, Sheep, and Gvat is very large, and closes an aper- ture left between tle sphenoid and pilate bones. 1l. Zygoma.—The jugal bone of Ruminants is very developed. The zygomatic crest is no longer formed by the posterior border of the bone, but is carried to the posterior part of the external face, and runs parallel with the eyebrow. The summit is bifurcated, the anterior branch form- ing a buttress against the summit of the orbital process of the frontal bone, while the posterior articulates with the temporal. 12. Lachrymal bone—The lachrymal bone, much more extensive than that of the Horse, forms in the bottom of the orbit an enormous protube- rance, hollowed internally by the maxillary sinus, and whose walls are so thin and fragile that the slightest jar is sufficient to cause their fracture (in the skeleton). It would be convenient to designate it the lachrymal protuberance.’ In the smaller ruminants, the inferior region of the exter- nal face shows a depression, the lachrymal fossa. 13. Nasal bones—Thbe nasal bones of the. Ox are never consolidated with each other, nor yet with the neighbouring bones. The external border only comes in contact to a small extent with the supermaxillary bone; the superior extremity is fixed in the notch of the inferior border of the frontal bone. At their inferior extremity, they each present a notch which divides them into two points. In the Sheep and Goat the nasal spine is unifid, as in the Horse. 14, Turbinated bones.—In the Oz, the eth- moidal turbinated bone is very small, and united to the nasal bone by the two borders of its osseous plate; its internal cavity entirely belongs to the frontal sinus. The maxillary turbinated bone is very developed, and is joined to the bone which sustains it at a later period than in the Horse. The bony lamina of which it is composed is curved 1 Girard, who named this eminence the orbital protuberance. wrongly described it as belonging to the supermaxillary bone. 5) —— Z MEDIAN AND VERTICAL SECTION OF THE OX’S HEAD. 1, Condyloid foramen; 1', Posterior ori- fice of the occipital lateral canal joining the parieto-temporal canal in front; 2, Internal auditory hiatus; 3, Anterior foramen lacerum; 4, Pos- terior ditto; 5, Intra-cranial orifice of the parieto-temporal canal; 6, 6, Median bony plate separating the frontal sinuses; 7, Lamina which iso- lates the sphenoidal sinus; 8, Lamina partitioning the palatine portion of the maxillary sinuses, 9, Oval fora- men; 10, Optic fossa; 11, Vomer; 12, Pterygoid bone; 13, Large open- ing leading into the maxillary sinus, and which, in the fresh state, is closed by the pituitary membrane; 14, Max- illary turbinated bone, 15, Ethmoidal turbinated bone; 16, Great ethmoidil cell. 60 THE BONES. on itself in two different directions: from before to behind by its posterior border, and behind to before by its anterior border. It is fixed to the supermaxillary bone by its middle part, through the medium of a particular bony lamina, and it very incompletely closes the excavation which concurs to form the maxillary sinus. In the skeleton there is also’found behind, und at the base of this turbinated bone, a vast opening which is totally closed in tlie fresh condition by the pituitary membrane. The maxillary sinus is not prolonged in its interior. In the smaller ruminants, the cavity of the sinus is clused by the maxillary turbinated bone in a more complete manner than in the Ox. 15. Vomer.—This is a very large thin bone, resting only on the inferior half of the i he premaxillaries. Tener eee 16. Premawillary bone.—In the Oz, the inferior part of the posterior border is convex, and cannot rest on a horizontal plane by all its points at the same time. The condyle is convex in its small diameter, and slightly concave laterally. The coronoid process is bent backwards and outwards. The body does not show any alveolus for the tusk, because this tooth is absent in these animals; but it is hollowed by eight alveoli for the incisor teeth. The two branches of the bone are never consolidated, but remain movable on each other during life. 17. Hyoid bone—The hyoid bone of Ruminants is always composed of seven pieces; the styloid nucleus, whose presence is not constant in solipeds, is never absent in these, and assumes the proportions of a second small branch. The anterior appendix is very short and thick. B, Heap or rue Pic.—l. Occipital bone—The occipital bone in this animal is not bent anteriorly; but the transverse protuberance representing the curved lines forms, nevertheless, as in the Horse, the summit of the head. This eminence, which is excavated on both sides on the posterior face, unites in front with the parietal bone, which abuts on the occipital at an acute angle. There is no external occipital protuberance, properly speaking, and the styloid processes are very long and directed downwards. 2, Parietal bone.—This bone is very thick, and deprived of an internal protuberance. The process concurring to cir- cumscribe the orbit is short, and joins neither the zygomatic or temporal bones; the orbital arch is completed by a liga- ment. The superciliary foramen, disposed as in the Ox, opens in front into a channel that descends to the nasal bones. The orbital foramen is formed by the frontal bone only. There is no mortice for the union of the frontal with the sphenoid bone, and the maxillary sinus is prolonged into the parictal bone. The frontal bone of the pig articulates with the super- maxillaries, 3. Frontal bone—The frontal bone of the Pig is very thick Fig. 31. HEAD OF THE PIG35 ANTERIOR FACE. 1, Summit of occipital pro- tuberance; 2, Parietal bone; 3, Frontal bone. —A, Superciliary fora- men; A’ Channel des- cending from it.—4, Zygomatic process; 5, Zygoma; 6, Lachrymal bone.—B, — Lachrymal canals.—7, Supermax- illary bone.—c, Inferior orifice of the supermax- illo-dental canal; 8, Nasal bone; 9, Pre- maxillary bone. and short, and does not join the t-mporal or zygomatic bone ; the orbital arch is completed bya ligament. The superciliary foramen, disposed as in the Ox, abuts in a channel that descends on the nasal bones. ‘The orbital foramen is formed by the frontal bone only. There is no mortice for the union of the frontal with the sphenoid bone ; and the frontal sinuses are prolonged into the parietal. The frontal bone of the Pig articulates with the supermaxillaries. 4. Sphenoid bone.—The sphenvid of the Pig is very short, but the subsphenoidal processes are extraordinarily developed and flattened before and behind. There is no subsphenoidal canal, and the sella tureica is deep, and limited behind by a very salient crest. A single canal replaces the foramen rotundum and the great sphenoidal fissure, as in the Ox. The wings, slightly salient, are articulated by suture with the frontal bone. 5. Temporal bone.—The articular surface of this bone resembles that of rodents ; it is not limited posteriorly by a subcondyloid eminence, and, in addition, offers a wider transverse surface. ; _ The zygomatic process articulates with the jugal bone by the whole extent of its posterior border. A crest leading from the external auditory hiatus to the THE HEAD, mastuid protuberance replaces the mastoid process. confounded with the superior root of the zygomatic p The projcction formed by the mastoid protuberance is enormous. 61 The mastoid crest is, as in the Ox, rocess, The subuliform process is little marked, and there is no hyoideal prolongation or parieto-temporal canal. 6. Supermaxillary bone—In the Pig, the ex- ternal surface of this bone is hollowed in its middle, and presents in front a voluminous relief formed by the alveolus of the canine tooth. ‘The cavity is entirely formed in the supermaxilla. ‘here is no alveolar tuberosity, and the interdental space is very short, while the cavity for the sinus is little developed. ‘The lower orifice of the palatine canal is even pierced in the substance of the super- maxilla. 7. Premaxillary bone—The external process of the premaxillary bone is very long and wide at its base, and consolidated with the nasal bone for about the upper two-thirds of its length. ‘There is no incisive foramen or cavity for the tusk. ‘The incisive openings are oval. 8. Palate bone —The palatine portion of the ex- ternal face is more developed than in the Ox, but the orbital portion is ‘very limited. The palatine crest is rvplaced by a tuberosity, against which rests, outwardly, the subsphenoidal process, and inwardly, the pterygoid bone. The union of these three parts constitutes, on the posterior surface of the head, a thick and very remarkable trifid pro- jection or mamelon. 9. Pterygoid bone—Sce the description of the palate bone. 10. Zygomatic bone-—The summit of this bone in the Pig is flattened on each side, and divided into two bianches, between which is wedged the summit of the zygomatic process; the anterior branch is very short, and does not join the frontal bone. 11. Lachrymal bone.—In the Pig there are ob- served a lachrymal fossa and two lachrymal canals, which are pierced outside the orbital cavity, and soon coalesce in the substance of the bone to consti- tute a single canal. The fossa is very deep. 12. Nasal bones.— These bones are long and nar- row, and traversed on their external face by the fissure that descends from the superciliary foramen. The nasal prolongation is short. 13. Turbinated bones——The same arrangement as in the Sheep and Goat, except that they are much longer and less fragile. 14. Inferior Mazilla.—A straight line leading from the greater axis of the alveoli of the molar would not traverse the posterior border of the maxillary branches; the bottom of these alveoli corresponds to the relief on the inner face. The condyle is compressed on both sides, and elongated from before to behind ; while the coronoid prucess is short and wide. There igs no neck; the interdental spaces are very short; and the maxillo-dental canal opens inferiorly by multiple orifices. : P 15. Hyoid bone.—The body is voluminous and deprived of an appendix; the small branches are Fig. 32. HEAD OF THE PIG; POSTERIOR FACE 1, Occipital protuberance; 2, Occi- pital foramen; 3, Occipital con- dyle; 4, Condyloid foramen; 5, Basilar process ; 6, 6, Mastoid crest; 7, Styloid process of the occipital bone; 8, Articular surface of the temporal bone; 9, Mastoid protu- berance; 10, Foramen lacerum; 11, Subsphenoidal process — external wing of pterygoid process; 12, Palatine crest; 13, Pterygoid bone internal wing of the pterygoid process; 14, Inferior orifice of the palatine canal; 15, 15, Incisive openings. short and consolidated with the body; while the large branches, curved like an S, are very thin, and are united to the small branches and the temporal bone no longer by fibro- cartilage, but by veritable yellow elastic ligaments, C. Heap or Carnivora.—l, Occipital bone-—The eminence which constitutes the 62 THE BONES. origin of the superior curved lines is very elevated and strong. The cervical tuberosity of the external occipital protuberance is absent or little marked ; the styloid processes are short, and well deserve the name of jugular eminences. The foramen lacerum is divided into two portions by the mastoid protuberance, and the basilar process is wide, long, and thick, and hollowed on the side by a channel that joins a similar one in the temporal bone to form a large venous canal. This last communicates, behind, with the posterior foramen lacerum, and opens, in front, in the cranium, where it is continuous with the cavernous groove of the sphenoid. The anterior angle forms a very marked prominence, which is deeply fixed into the parictal bone, and partly constitutes the internal protuberance of that bone. f 2. Parietal bone.—In the Dog the parietal bone, formed by two ossific centres only, is distinguished by the great development of the ridges and the parietal protuberance. This last, constituted in part by the occipital bone, does not show any lateral excavations at its base; they are carried lower, near the summit of the petrous process, on the sides of the occipital bone. The parieto-temporal canals are continued, notwithstanding, to the base of the protuberance, which they traverse, to Fig. 33. open into each other in its interior. In the Cat there are scarcely any parietal crests, and the internal protuberance is replaced by two great trans- verse bony plates which separate the cavity of the cerebrum from that of the cerebellum. 3. Frontal bone.—In carnivora, the external face of this bone presents in its middle a more or Jess marked de- pression. The orbital arch is incomplete, and there is no superciliary foramen, or mortice on the inner face. The bone is united with the supermaxillaries. 4. Ethmoid bone —The ethmoidal fossa is very deep, avd the cells very developed and diverticulated. The per- pendicular lamina is at a late period consolidated with the sphenoid bone. 5. Sphenotd bone-—The superior sphenoid of the Dog is very short, and bears, laterally, two wide wings which ascend to the temporal fossa; they correspond to those of the sphenoid bone in Man. The inferior sphenoid is, on the’ contrary, very narrow, and its Jateral prolongations, or pro- cesses of Ingrassias, are reduced to very small proportions. The sub-sphenoidal or pterygoid process is very short, and the canal is single, and communicates with the foramen rotundum. The pituitary fossa is shallow, limited behind and before by the posterior clinotd and anterior clinoid HEAD OF DOG; ANTERIOR processes, SO named because of their being compared to the FACE. four posts of an pee bed. The supersphenoidal canals int : ‘ance: 2, #re only two in number: one represents the great sphenoidal hi Met ee ee fissure. the other the round foramen. The carotid notch, pital bone; 3, Parietal Joining @ similar one in the temporal bone, forms an open- bone; 4, Origin of the pa- ing which may be designated the carotid foramen, because rietal crests; 5, Zygomatic it gives passage to an extremely remarkable loop the in- process of the temporal ternal carotid artery describes after passing through the bone; 6, Frontal bone; 6’, carotid canal. The oval foramen is the same as in the Ox. Orbital’ process; 7, Zy- In the Cat there is the same disposition, with the ex- goma3 8, Lachrymal bone; ception of no sphenoidal canal or carotid notch being present. 9, Nasal bone; 10, Super- 6. Temporal bone.—In the carnivora, the articular sur- maxilla; 11, Inferior ori- face of the zygomatic process merely forms a glenoid fice of the supermaxillo- cavity, into which the eondyle of the maxillary bone dental canal; 12, Pre- exactly fits. The temporal bone in these animals is also maxillary bone. distinguished by the width of the external auditory canal, the absence of a hyoid prolongment, the small development ; of the mastoid and styloid processes, the enormous volume of the mastoid protuberance, and the presence of two paiticular canals which cannot be traced in the other animals. One of them, the carotid canal, traverses the mastoid portion, and joins, superiorly, the venous canal which passes between the basilar process and the temporal bone; by its inferior extremity it joins the carotid foramen which itself penetrates the cranium, a little beyond the venous canal just mentioned. The other conduit is pierced in the petrous portion immediately above the carotid canal ; it affords a passage to the fifth pair of encephalic nerves. THE HEAD, 63 7. Supermazillary bone—In carnivora, this bone is very short; its anterior border offers a long process analugous to the nasal spine of Man. It alone furnishes the alveolus of the tusk. The palatine canal, pie:ced entirely in the bone of that na —_ ! } L L me, neverthe opens, by its inferior extremity, at the junction of the supermaxillary with he ue bone. ‘The maxillary sinus is not very spacious, and there is no maxiliary spin 8. Premaxillary bone.—Ot little size, the premaxillary of carnivora has no incisive foramen or alveolar cavity for the canine tooth. The incisive openings are the same as in the Pig. 9. Palate bone.—In the carnivora, the palate bones are of great extent in their proper palatine portion. ‘They have no Share in the formation of the spheuoidal sinuses, but furnish a small excavation to the maxillary sinuses. 10. Pterygoid bune—This bone is very strong in car- nivora, and quaurilateral in shape. 11. Zygoma.—The zygoma of the Dog and Cat only articulates with the supermaxillary bone by its base. The crest describes a curve backwards, and the summit com- ports itself as in the lig. 12. Lachrymal bone.—This bone in carnivora is ex- tremely small. Its external face entirely belongs to the orbit, and does not descend beneath the margin of that cavity; it has no lachrymal fossa. 13. Nasal bone-—The two bones of the nose are little developed, and are wider below than above; they have no nasal prolongation, but offer instead a semicircular notch. 14. Turbinated bones.— These bones in the Dog and Cat are particularly distinguished for their numerous convo- lutions. Neither participate in the formation of the frontal or maxillary sinuses; the latter is not in any way closed by the maxillary turbinated bone, but opens into the nasal cavity by a lurge gaping aperture. 15. Inferior maxillary bone—In carnivora, this is hollowed at the point corresponding to the insertion of the masseter murcle into a sumewl.at dcep fossa, The posterior border is disprsed as in ruminants, and below the condyle has a very marked tuberosity. The condyle represents an ovoid segment, and fits exactly into the temporal cavity. The co:onoid process is very strong, elevated, and wide. The mental foramina are double or treble. There are no interdental spuces, nor excavated surface on the inner face of the branches; and the latter are never consolidated. 16. Hyotd bone.—The three pieces composing the body of the hyoid in early life are never consolidated in the adult animal, but always remain isolated, as in Mun. The middle piece las no anterior appendix; the tibro- cartilages uniting the styloid portions tv each other and to the temporal bone are very long and flexible. COMPARISON OF THE HEAD OF MAN WITH THAT OF THE DOMESTICATED ANIMALS. 1. Occipital bone.—The occipital of Man is large, flat, incurvated like a shell, and the external protuberance is slightly developed, and united by a ridge to the occipital foramen, which is relatively very wide. Two serie§ of ridges arise from the external protuberance and pass towards the circumference of the bone; these are the superior and inf-rior curved or semicirenlar lines. There is an anterior and a posterior condyloid fossa pierced by a Fig. 34 DOG’S HEAD ; POSTERIOR FACE, 1, Occipital protuberance; 2, Occipital foramen; 3, Occi- pital condyle; 4, Condyloid foramen; 5, Styloid process of the occipital; 6, Mastoia protuberance; 7, Concave temporo-maxillary articular surface ; | 8, Supercondy- loid eminence; 9, Inferior orifice of the parieto-tem- poral canal; 10, Lacer- ated foramen, posterior; 11, Ditto, anterior —On the op- posite side at a is shown the orifice communicating with the Eustachian tube and the tympanum; at 6 the passage for the carotid convolution.—12, Body of the sphenoid; 13, Oval fora- men; 14, Interior orifice of the subsphenoidal canal; 15, Pterygoid bone; 16, Nasal surface of the palate bone; 17, Palatine surface of the same; 18, Vomer; 19, Supermaxillary bone; 20, Incisive opening. foramen at the boitom; and the jugular eminences, wide and slightly prominent, re- place the styloid processes of the domesticated animals. The internal face of the ovcipital of Man corresponds with the cerebrum and 64 THE BONES, cerebellum ; and for this purpose it shows four fosse, distinguished into superior or cerebral, and inferior or cerebellar. These fosse are separated by a crucial projection whose most developed portion forms the internal occipital protuberance. , The union of the occipital with the parietal bones constitutes the lambdoidal suture. At the point where this bone meets the parietal and the squamous portion of the temporal, is found, in the infant, the lateral posterior fontanella. ; ; 2, Parietal bones—The parictals are always isolated in early life, and_ sometimes consolidated with each other at the adult age. They are very large, quadrilateral, and occupy the summit and sides of the cranium. Fig. 35. FRONT VIEW OF THE HUMAN CRANIUM. 1, Frontal bone; 2, Nasal tuberosity ; 3, Supra-orbital ridge; 4, Optic foramen; 5, Sphenoidal fissure; 6, Spheno-maxillary fissure; 7, Lachrymal fossa; 8, Opening of the nose divided by the vomer; 9, Infra-orbital foramen; 10, Malar bone; 11, Symphysis of the lower jaw; 12, Mental foramen; 13, Ramus of the lower jaw; 14, Parie- tal bone; 15, Coronal suture; 16, Temporal bone; 17, Squamous suture; 18, Upper part of the great ala of the sphenoid bone; 19, Com- mencement of the temporal ridge; 20, Zygoma of the temporal bone, concurring to form the temporal arch; 21, Mastoid process. of the orbit The parietal crests are absent, but are replaced, in certain individuals, by two faintly-marked curved lines situated a little above the inferior border of the bone. The middle portion of the external face is very convex. : On the internal face there is no parietal pro- tuberance, but in its stead the internal occipital protuberance. It also exhibits ramous channels, which in disposition are analogous to the ribs of a fig-leaf; as well as the parietal fossa which cor- responds to the parietal eminence. 3. Frontal bone—The frontal bone of Man forms the upper part of the face and the anterior portion of thecranium, Convex from behind forward, then vertical in its upper three-fourths, the bone sud- denly bends at the orbits, so as to become hori- zontal in its lower fourth. The external face offers, above the forehead, two lateral frontal eminences, and above the nose, a middle frontal boss. To the right and left of the latter are two salient arches, the supraorbital ridges. ‘he internal face entirely belongs to the cranial cavity. It offers on the median line, the saggital groove terminated by a frontal crest; and on each side of this line the frontal fossz, corresponding to the eminences of that name, and orbital bosses to match the orbital roofs. There is no mortice for the articulation of the sphenoid bone. On the middle portion of the superior frontal border, in young persons, is the anterior angle of the anterior fontanella. The anterior border ex- hibits three superciliary foramina and the orbital arches. 4, Ethmoid bone.—In Man, the external face of the lateral masses, formed by a very thin lamina, termed the os planum or lamina papyrace, belongs to the internal wall of the orbit. 5. Sphenoid bone—This is distinguished, in Man, into a body and four wings, two large and two small. The inferior surface of the body offers nothing remarkable, except the presence of a conical pro- longation named the beak (rostrum) of the sphe- noid. The external face of the greater wings forms part of the temporal fossa, as also the external wall At the union of the wings with the body are detached two bifid ptery- goid processes; their internal branch represents the pterygoid bones of animals. ‘There is no subsphenoidal canal. The two lesser wings are very thin and triangular, and visible only on the superior sur- face of the bone; they constitute the processes of Ingrassias. On the internal face of the bone are found :—1, A deep pituitary fossa, limited by four clinoid processes: 2, An optic fossa, shallow, showing very short optic canals trans- formed into foramina: 3, The sphenoidal fissure, which replaces the great super- sphenoidal canal in the Horse; 4, The great foramen rotundum : 5, The internal face of the wings, much excavated ; 6, The foramen ovale, which transmits the inferior maxillary nerve; 7, The small foramen rotundum that lodges the spheno-spinous artery, THE HEAD. 65 6. Temporal bone.—In the squamous portion of the temporal bone of Man, the zygomatic process only rests on the malar bone, as in ruminants. The glenoid cavity is concave in every sense, and divided into two parts by an opening named the Glasert ; the anterior portion ouly is articular, the posterior lying against the gale auditory canal, does not belong to the articulation ; it corresponds to the supracondyloid eminence of the Horse. The tuberous portion is consolidated with the squamous. It is divided into a mastoid and a pyramidal portion; the latter ccmprises, in its turn, the petrous and tympanic portions, mastoid protuberance, and superior border of the a rugged mastoid process; above this is the mast digastric groove; the pyramid forming wu con- siderable projection in the interior of the cra- nium. The styloid process or bone is altogether separate from the other pieces of the byoid, and in the adult is consolidated with the temporal bone. 7. Supermazilla—tIn Man the premaxilla is no longer found independent, the centre which formsit coalescing with the supermaxillary bone. The supermaxilla of Man concurs, for the greater part of its extent, to form the floor of the orbit; it is also divided into three faces: an external or facial, a superior or orbital, and an internal or naso-palatine. The external face presents, from before to behind: 1, A small fossa, into which is inserted the myrtiform muscle; 2, The infraorbital, or canine fossa, showing the inferior orifice of the infraorbital canal; 3, A crest corresponding to the maxillary spine of solipeds; 4, The alveolar tuberosity. This face carries, in front, a prolongation that forms the ascending process, also named, be- cause of its relation, the fronto-nasal process. The superior or orbital face offers a fissure which precedes the infraorbital canal, and, outwards, the malar process. The internal face is divided by the palatine process. It shows, in front, the half of the anterior nasal spine and a groove which participates in the formation of the in- cisive canal. _ &. Palate bone.—The palate bone of Man is formed of two osseous Jaminz: one horizontal, the other vertical, which are joined at a right angle. The first part presents’ one-half of the posterior nasal spine, which is altogether rudi- mentary, or even null in animals; the orifice of the posterior palatine canal, which belongs entirely to the pulate bone; the pterygo-palatine foramen; lastly, the pterygoid process, which represents the pterygoid bone of animals. The vertical portion forms the external wall of the nasal cavities by its internal face, and by its ex- ternal face concurs in the formation of the zygomatic or temporal fossa. 9. Zygoma.—This offers three faces. The external, or cutaneous, serves as a base for the most salient part of the cheek. The superior, or orbital, forms part of the external wall and floor of the orbit; it belongs to a long apophysis, the orbital process, which rests on the sphenoid and frontal bones. The mastoid portion corresponds to the mastoid process, petrous bone in the Horse. It presents’ oid canal; and above and behind it, the EXTERNAL OR BASILAR SURFACE OF THE BASE OF THE HUMAN SKULL 1,1, The bony palate; 2, Incisive, or anterior palatine foramen; 3, Palatine process of palate bone, with the pos- terior palatine foramen; 4, Palate spine with transverse ridge; 5, Vomer ; 6, Internal pterygoid palate; 7, Sca- phoid fossa; 8, External pterygoid plate, with fossa; 9, Zygomatic fossa ; 10, Basilar process of occipital bone ; 11, Foramen magnum; 14, Glenoid fossa, 15, Meatus auditorius exter- nus; 16, Foramen lacerum anterius,; 17, Carotid foramen of left side; 18, Foramen lacerum posterius, or jugular foramen; 19, Styloid process; 20, Stylo-mastoid foramen, with jugular tubercle and digastric fossa; 21, Mas- toid process; 22, Occipital bone; 23, Posterior condyloid fossa, The posterior face is smooth and concave behind, where it aids to form the temporal fossa; in front it is uneven, and articulates with the supermaxilla. The posterior, or masseteric border, unites with the zygomatic process of the temporal bone. 10. Lachrymal bone.—This bone is also called the os unguis in Man, because of its likeness to the nail in shape and tenuity. It is entirely lodged in the orbit, and its 66 THE BONES. external face is divided into two portions by a vertical crest; the portion situated in front of this crest forms part of the lachrymal channel. By its internal face, the lachrymal bone limits, outwardly, the bottom of the nasal cavities, and covers the anterior cells of the ethmoid; by its posterior border, within the orbit, it articulates with the os planum of the ethmoid. on 11. Nasal bone.—The proper bones of the nose of Man exhibit a great analogy to those of the Dog. They do not possess a nasal prolongation, and they articulate with the lateral cartilage of the nose. ; ; 12. Vomer.—The same general form and relations as in solipeds, : 13. Inferior maxillary bone.—This bone in Man is in shape somewhat like a horse- shoe. It is nearly of the same width throughout its whole extent. The symphysis is vertical—a character peculiar to Man. Below this symphysis 1s a triangular projection, the mental eminence The genial surface of the Horse is replaced by four little tubercles termed the genial processes. The alveoli of the molar teeth form a great projection on the inner face of the bone. The mylo-hyoid ridge is very developed. The superior orifice of the dental canal is covered by a litile sharp lamina. From this orifice begins the mylo-hyoidean groove. The coronoid process is short; the condyle is bent towards the median line, and the sigmoid notch is wide and shallow. The superior border contains fourteen or sixteen alveoli. ArticLe IJI.—Tue THorax. The thorax represents a conoid cage, elongated from before to behind, suspended under the vertebre of the dorsal region, and destined to contain the principal organs of respiration and circulation. It is composed of bony arches named ribs, thirty-six in number—eighteen on each side—and a single piece, the sternum, which serves for the direct or indirect support of the inferior extremities of the ribs. THE BONES OF THE THORAX IN PARTICULAR. 1. Sternum of the Horse. This is an osteo-cartilaginous body, elongated from before backwards, flattened on each side in two-thirds of its anterior extent, and from above to below in its posterior third, slightly curved on itself, and situated beneath the thorax in an oblique direction from above to below, and before to behind. It offers for study. a superior face, two lateral faces, three borders, and two extremities. Fig. 37, THE STERNUM. 1. The cervical prolongation (or cariniform cartilage); 2, The xiphoid appendage (or ensiform cartilage; 3, 3, Cavities for the articulation of the sternal cartilages; 4, Inferior border. Faces.—The superior face, slightly concave longitudinally, represents an isoscelated, lengthened triangle, the summit of which is directed forwards: it constitutes the floor of the thoracic cavity. ach lateral face comprises two parts—a superior and an inferior, The first shows eight diarthrodial THE THORAX. 67 cavities, which receive the inferior extremity of the cartilages of the true ribs. These cavities are elongated vertically, and draw closer to each other as they extend backwards. The inferior part, which is more extensive before than behind, offers to the powerful pectoral muscles a large surface for insertion. Borders.—The two lateral borders separate the superior from the lateral faces ; they are situated above the diarthrodial cavities, are united anteriorly, and each gives attachment to a fibrous band. The inferior border is opposite the superior face ; convex, thin, and very prominent in its anterior two-thirds, it somewhat resembles the keel of a ship. Extremities.—The anterior flattened on each side and curved upwards, exceeds to some extent the first articular cavity of the lateral faces, and in this way constitutes the cervical prolongation of the sternum. The posterior extremity is flattened superiorly and inferiorly, and forms a large cartila- ginous plate, very thin, concave above, convex below, which has received the name of the abdominal prolongation (ensiform cartilage) or xiphoid appendage. Structure and development.—The sternum is one of the parts of the skeleton which do not submit to complete osseous transformation. It is developed, in solipeds, from six single centres of spongy substance, ranged one behind the other, like beads on a string. These centres never coalesce to form a solid piece, but remain separated, during the life of the animal, by the primitive cartilaginous mass. The latter constitutes the entire anterior pro- longation of the bone and its carina, as well as the xiphoid appendage. When these parts of the sternum become ossified, which is rare, it is only partially. 2. The Ribs. As has been already noticed, on each side of the thorax eignteen ribs are counted. These are nearly parallel to each other, and separated by the intervals termed the intercostal spaces. Attached by their superior extremity to the vertebra of the dorsal region, these bones terminate at their inferior extremity by an elastic and flexible prolongation, named the costal cartilage, by means of which they are brought into direct or indirect relations with the sternum. The characters common to all the ribs will be first noticed, then the special features which serve to distinguish them from each other, and, lastly, the differences they exhibit in other than soliped animals. A. CHARACTERS COMMON To ALL THE Rips.—These will be studied from a typical point of view, first in the rib itself, and then in its cartilage. 1. Description of a typical rib—A rib is an elongated symmetrical bone, oblique from above to below, and from before to behind, flattened on both sides, curved like a bow, and twisted on itself in such a fashion that its two extremities cannot rest on the same horizontal plane. It is divided into a middle portion and two extremities. Middle portion.—This offers two faces and two borders. The external face is convex, and hollowed by a wide groove in its anterior half; it shows superiorly, towards the point corresponding to the angle of the rib in Man, some tubercles and muscular imprints. ‘lhe internal face is concave and smooth, and covered by the pleura, which separates it from the lungs. The anterior border is concave, thin, and sharp; the posterior, convex, thick, and covered with rugged eminences, is channeled inwardly by a vasculo-nervous fissure, which disappears near the middle of the rib. Extremities—The superior has two eminences, a head and a tuberosity, which serve for the support of the rib against the spine. The first is formed by two articular demi-facets, placed one before the other, and separated by a 68 THE BONES. groove for ligamentous insertion; it is isolated from the tuberosity by a narrow part, named the neck, which exhibits a rugged fossa for the implanta- tion of a ligament. The second, situated behind the head, and smaller than it, is provided with imprints on its margin, and presents an almost flat diarthrodial facet at the summit. Each rib articulates by its head and tuberosity with two dorsal vertebre ; the head is received into the inter- Fig. 38, TYPICAL RIBS OF THE HORSE. A, Inner face of the fifth sternal rib; B, External face of the first asternal rib.— 1, Head of the mb; 2, Its fissure; 3, Neck; 4, Tuberosity ; 5, Articular facets 6, Scabrous fossa for the insertion of the interosseous costo-transverse ligament 5 7, Groove on the external face; 8, Vasculo-nervous groove of the posterior pe 9, Prolonging cartilage; 10, a, Articular tuberosity for union with the sternum. vertebral articular cavity; the tuberosity corresponds, by its facet, to the transverse process of the posterior vertebra. ; _ The inferior extremity is tuberous and excavated by a shallow cavity irregular at the bottom, for the reception of the upper end of the costal cartilage. Structure and development.—The ribs are very spongy bones. especially LHE THORAX. 69 in their inferior moiety, and are developed at a very early period by three centres of ossification: a principal for the middle portion and inferior extremity, and two complementary for the head and tuberosity. 2. Description of a typical costal cartilage—The costal cartilage very evidently represents the inferior rib in birds; it is a cylindrical piece, slightly compressed at the sides, and round and smooth on its faces and borders. By its superior extremity, it is united to the rib it serves to lengthen, and forms with it an angle more or less obtuse, opening in front. At its inferior extremity, it is terminated by an articular enlarge- ment, or by a blunt point. In youth, the costal prolongations are entirely composed of cartilaginous matter, but they are soon invaded by ossification ; so that in the adult animal they are already transformed into a spongy substance, with large areole which remain during life surrounded by a thin layer of cartilage. B. Spsctric Cuaracters or THE Rrss.—The ribs, like the vertebrae of each region of the spine, have received numerical designations of first, second, third, etc., computing them from before to behind. (See Fig. 1.) Owing to the pre- sence of an altogether essential characteristic, they are naturally divided into two great categories: the sternal or true ribs, and the asternal or false ribs. The sternal ribs, numbering eight (the first eight), have their cartilages terminating inferiorly by an articular enlargement, which corresponds to one of the lateral cavities of the sternum, and brings the true ribs into direct contact with this portion of the skeleton. The asternal ribs, ten in number, rest on each other—the last on the seventeenth, this on the sixteenth, and so on-—by the inferior extremity of their cartilage, which ends in a blunt point. The cartilage of the first false rib is united somewhat closely to the last sternal rib, and it is through the medium of this that all the asternal ribs lie indirectly on the sternum. If, however, the ribs are considered altogether, with regard to the differen- tial characters presented by them in their length, width, and degree of incurvation, it will be noted: 1, That their length increases from the first to the ninth, and from this diminishes progressively to the last: 2, That the same progressive increase and decrease exists in the cartilages; 3, That they become gradually wider from the first to the sixth inclusive, and then con- tract by degrees until the eighteenth is reached ; 4, That the curve described by each is shorter and more marked as the rib is situated more behind. It may be added that the channel on the external face is less conspicuous in proportion as the rib is narrow. The first rib, considered individually, is always distinguished by the absence of the groove on its outer surface, the vasculo-nervous fissure on its posterior border, and the groove or notch intermediate to the two facets of its articular head. It is also recognised by the deep muscular imprints on its external face, the shortness and thickness of its cartilage. and particularly by the articular facet which this cartilage exhibits inwardly, to correspond to that of the opposite rib. The last rib has no channel on its ‘external surface; the facet of its tuberosity is confounded with the posterior facet of the head. This last character is- also nearly always remarked in the seventeenth rib, and sometimes even in the sixteenth. In the Ass and Mule, all the ribs in general, but particularly those most posterior, are less curved than in the Horse. (In the Horse, a nineteenth pair of ribs is sometimes found, and this even with five, and at other times with six lumbar vertebre; it happens that the nineteenth rib is formed by the transverse process of the first lumbar vertebra, and at times a ligament 8 70 THE BONES. is given off from this process, which joins it to a pointed bone or @ cartilage in its vicinity. If the hymn on the ‘Sacrifice of the Horse,” in the most ancient collection of Aryan poems, is to be credited, the horses of antiquity in Central Asia had only seventeen pairs of ribs. The mobility of the ribs is scarcely perceptible in the first, but increases until the ninth or tenth is reached, after which it gradually diminishes.) THE THORAX IN GENERAL. The description of the interior of the thoracic cavity will be referred to when treating of the respiratory apparatus. It is only necessary here to examine the external surface of this bony cage; for this purpose it is divided into six regions :—a superior plane, an inferior plane, two lateral planes, a base, and a summit. Planes.—The superior plane is separated into two portions by the spinous processes of the dorsal vertebra ; each forms, with these spinous processes, the costo-vertebral furrow, intended to lodge the majority of the muscles belong- ing to the spinal region of the back and loins. The inferior plane, less extensive than the preceding, offers: 1, On the median line, the cariniform and xiphoid cartilages of the sternum; 2, On the sides, the chondro-sternal articulations, and the cartilages of prolongment of the true ribs. The lateral planes are convex and wider at their middle part than in front or behind, and exhibit the intercostal spaces. They serve to give support, anteriorly, to the superior rays of the two fore-limbs. Base.—This is circumscribed by the posterior border of the last rib, and by the cartilages of all the asternal ribs; it is cut obliquely from above to below, and from before to behind. It gives attachment, by its internal circumference, to the diaphragm, a muscle which separates the thoracic from the abdominal cavity. Summit.—lt occupies the anterior portion of the thorax, and presents an oval opening, elongated vertically, situated between the two first ribs. This opening constitutes the entrance to the chest, and gives admission to the trachea, the cesophagus, and important vessels and nerves. DIFFERENTIAL CHARACTERS OF THE THORAX IN OTHER THAN SOLIPED ANIMALS. 1, Sternum, In all the domesticated animals except solipeds, the sternum is flattened above and below, instead of from side to side. _ Rusmnayrs.—In ruminants, each piece is developed from two lateral centres of ossifica- tion. The bones which compose it are seven in number; they are much more compact than those in the sternum of the horse, and at an early period are united to each other, with the exception of the first, which is joined to the second by a diarthrodial articula- tion that permits it to execute lateral movements. There is no cervical prolongation, and the xiphoid cartilage is feebly developed and well detached from the body of the bone. In the sternum of the Goat and Sheep, the two first pieces have no diarthrodial joint, but are simply united by a layer of cartilage which, in old animals, becomes completely ossified. : Pia.—The sternum of this animal presents in its general conformation the essential features of that of large ruminants. It is provided with a well-defined cervical prolonga- tion, and is composed of six pieces which, at least in the four or five last, are each divided into two lateral centres. : j Carnivora.—The sternum of the Dog and Cat is formed of eight pieces elongated from ‘before to behind, hollowed in their middle part, and thick at their ends—formed, indeed, like the last coccygeal vertebrae of the Horse. They are never ossified to each other. THE THORAX, 71 2. Ribs. : The number of ribs varies like that of the dorsal vertebre. The following table indicates the number of these bones in the ditterent domesticated animals. Pig s th . 14 Ose! gs ley ee ae ae ee Sheep. ° . . . . . 13 Goat'e, eae oe a aS DOS wh: Serie viel es we Rominants.—These animals have eight sternal and five asternal ribs. In the Ox, they are longer, wider, and less arched than in solipeds. The articular eminences of the superior extremity are voluminous and well detached; the neck especially is very long. The sternal ribs are joined to their cartilage of prolongment by a real diarthrodial articulation. In the last rib, and sometimes in the one before it, the tuberosity is scarcely perceptible, and has no articular facet. In the Sheep and Goat, the sternal ribs are consolidated with the cartilages (see fig. 5.) Pic.—In this anima] there are fourteen pairs of ribs, seven of which are sternal and seven asternal. The first are provided with cartilages of prolongment flattened on both sides, extremely wide aud sharp, and convex on their superior border. In the four last asternal ribs, the facet of their tuberosity is confounded with the posterior facet of the head. (Otherwise, the ribs of the Pig resemble, in their general conformation, those of the Sheep or Goat; though more incurvated and wider.) CarNivora.—They possess thirteen ribs on each side—nine sternal and four asternal. These are very much arched, narrow, and thick, and their cartilages rarely ossify. In the Dog, the articular facet of the tuberosity remains isolated from the posterior facet of the head in all the ribs. It is absent in the three last ribs of the Cat. COMPARISON OF THE THORAX OF MAN WITH THAT OF THE DOMESTICATED ANIMALS, 1. Sternum. The sternum of Man is flattened before /A\ and behind, and diminishes in width from [\¥g above to below. The xiphoid appendage is narrow, and single or bifid. Besides the articular surfaces for the ribs, there are found -on the upper end two lateral notches for articulation with the clavicles. 2. Ribs. Of the twelve ribs in Man, seven are sternals and five asternals. They are short, narrow, and much incurvated, especially the first ones. In each rib the curvature 1s more marked in the posterior fourth or fifth than in the anterior three-fourths or four- fifths; this sudden change of curvature Js indicated in the external face by a kind of inflexion and thickening called the angle of the ribs. The prolonging cartilages of the eleventh and twelfth ribs are short, and are lost in the texture of the abdominal parietes:; for this reason they are termed the floating (or false) ribs (see fig. 39). THORAX OF MAN; ANTERIOR FACE, 1, Superior piece of the sternum; 2, Middle piece, or body; 3, Inferior piece, or ensiform cartilage; 4, First dorsal vertebra; 5, Last dorsal vertebra; 6, First rib; 7, Its head; 8, Its neck, rest~ ing against the transverse process of the first dorsal vertebra; 9, Its tubercle; 10, Seventh, or last true rib; 11, Costal car- tilages of the true ribs; 12, The last two false or floating ribs; 13, The groove along the lower bérder of the rib. Agtiote IV.—AyteRion Lines. The anterior (or thoracic) the shoulder, arm, fore-arm, limb is divided into four secondary regions : and fore-foot or hand. 72 THE BONES. SHOULDER. In solipeds, this region has for its base a single bone, the scapula or omoplat. Scapula. This is a flat, triangular, and asymmetrical bone, prolonged — at its superior border by a flexible cartilage, articulated inferiorly with the humerus only, and applied against the lateral plane of the thorax in an oblique direction downwards and forwards. It has two faces, three borders, and three angles. Faces.—The external face is divided by the scapular or acro- mian spine, into two cavities of unequal width—the supra and infraspinous (or antea and postea spinatus) fossse. The spine isa very salient crest which runs the whole length of the external scapular surface; very elevated in its middle part, which shows an irregular enlargement—the tube- rosity of the spine—it insensibly decreases towards its two ex- tremities. The supraspinous fossa, the narrowest, is situated above, or rather in front of the - Spine; it is regularly concave . from side to side, and perfectly smooth, The tnfraspinous fossa is twice the width of the pre- ceding, and occupies all the sur- face behind the spine. It ex- hibits: 1, Below, and near the THE RIGHT SCAPULA}; OUTER SURFACE. 1, Antreior border; 2, Superior margin for insertion el A 1 of cartilage; 3, Tuberosity of the spine ;4, Antea- POSverlor bor er, several rows spinatus fossa; 5, Postea-spinatus fossa; 6, Neck of roughened lines for muscular of the scapula; 7, Coracoid process; 8, Glenoid insertion; 2, Near the neck, the une ae cavity! nutritious foramen of the bone, and some vascular grooves. The internal face is excavated in its centre to form a hollow called the subscapular fossa, which is prolonged superiorly by three diverging points. The anedian point extends to the superior border of the bone, and separates two roughened triangular surfaces destined for muscular implantation. Borders.—The superior is indented by an irregular groove to receive the inferior margin of the cartilage of prolongment. 'The latter is convex on its superior border, extends beyond the posterior angle of the bone, and gradually diminishes in thickness as it leaves its point of attachment. In old horses it is nearly always found partially ossified. The «anterior border, thin and sharp, is convex in its superior two-thirds, and slightly concave for the remainder of its extent. The posterior is thicker and a little concave. THE ANTERIOR LIMBS. 73 Angles.—The anterior or cervical angle is the thinnest of the three. The posterior or dorsal angle is thick and tuberous, The inferior or humeral angle is the most voluminous, and is separated from the remainder of the bone by a slight constriction, which constitutes the neck of the scapula. It exhibits : 1, The glenoid cavity, an oval diarthrodial surface, excavated to a slight extent to receive the head of the humerus, notched on the inner side and bearing on the external margin of the ridge which surrounds it a amall tubercle of insertion; 2, The \coracoid process, situated in front, and at a certain distance from the glenoid cavity. This is a large eminence in which may be distinguished two parts: the base, a thick rugged process ; and the summit, a kind of beak curved inwards. ; Structure and development.—Like all the wide bones, the scapula is formed of two compact lamelle separated by spongy tissue. The latter is yery scanty towards the centres of the supra and infraspinous fosse, where it is often altogether wanting; it is most abundant in the angles. The scapula is developed from two centres of ossification, one of which forms the coracoid pro- cess. Fig. 41. ARM, This region has only one bone, the humerus. AMumerus. The humerus is a long single bone, situated between the scapula and the bone of the fore-arm, in an oblique direction downwards and backwards. Like all the long bones, it offers for study a body and two extremities. Body.—The body of the humerus looks as if it had been twisted on itself from within to without in its superior extremity, and from without to within at the opposite end. It is irregularly prismatic, and is divided into four faces. The anterior face, wider: above than below, has in its middle and inferior por- tions some muscular imprints. The posterior, smooth and rounded from one side to the other, becomes insensibly confounded with the neighbouring faces. The external is excavated by a wide furrow, which entirely occupies it, and turns round the bone ob- liquely from above to below and bebind to before ; it is to the presence of this channel that the humerus ayrmro-exTeRNAL VIEW owes its apparent twist, a2PTCiggs "in consequence oF RIGHT HUMERUS. designated the furrow of tor: the body of the 1, Trochlear or bicipita humerus. ee i pe bale This furrow is separat 1 the anterior face fyasq or articulan by a salient border, the a wst of the furrow face; 4, External? of torsion, which ends inft , the | coronoid cle; 5,Shas ‘fossa, and superiorly, tow third of the om ; bone, by the imprint. Thisisa oO roughened, very pr haficce = y and behind, and ‘ ed torsion ; by-it= ' a, curved liz ” base ef 74 THE BONES, ¢ outwards, is seen the posterior crest of the furrow of torsion, which separates the latter from the posterior face of the bone. The interdal face of the body of the humerus, rounded from side to side, is not, separated from the anterior and posterior faces by any marked line of demarcation. © It offers, near its middle, a depressed scabrous process for the insertion of the adductor muscles—teres major and great dorsal—of the arm. Towards its inferior third it shows the nutritive foramen of the bone. Extremities —These are distinguished into superior and inferior. Both are slightly curved, the first backwards, the second forwards, a disposition which tends to give to the humerus the form of an S. The superior eatremity is the most voluminous, and has three thick eminences; a posterior, external, and internal. The Fig. 42, first constitutes the head of the humerus; it is a very slightly-detached articular eminence, rounded like the segment of a sphere, and corresponding to the glenoid cavity of the scapula, which is too small to receive it entirely. The external eminence, named the trochiter, large trochanter, and great tuberosity, com- prises three portions, named the summit, convexity, and crest of the great tuberosity. The internal eminence, the trochin, little trochanter, or small tuberosity, also presents three distinct portions, which, by their posi- tion, correspond exactly with the three regions of the large trochanter: these are so many muscular facets. Bi The great and small trochanters are separated from one another in front by a channel called the bicipital groove, because the superior tendon of the biceps muscle glides over it; it consists of two vertical grooves with a median ridge between them. The inferior extremity of the humerus has an articular surface corresponding to the radius and ulna. This surface, elongated transversely, convex from before backwards, and of greater extent within than without, exhibits two trochlea separated by an antero- posterior relief. e POSTERIOR VIEW OF THE . . ” . HIGHT KOMERYS: The .median or, internal trochlea, the deepest, is 2, External tuberosity; 3, limited internally by a kind of voluminous condyle, Articular head of the Which corresponds to the inner lip of the humeral bone; 4, External tu- trochlea of Man, ~ external trochlea is bordered ae ate i he outwardly by a sl salient lip, which corresponds bond; 10, Condyloid to the condyle of aumerus of Man. Above and +, fossa, behind this articul dace is a wide deep fossa, the «a 6 olecranian (or con. - Q named because it lodges the ‘the olecranon in the exteny ents of the fore-arm. It is *9 eminences, the er’ ry is less elevated than the rst represents ‘ and the second the epi- umervs.nf, Mai “ove the inner trochlea, pug cet Bat as the coronoid pro- vy this reason, it ihastly, at the ‘rface is THE ANTERIOR LIMBS. 15 remarked: outwardly, an excavation for ligamentous insertion ; inwardly a small tuberosity intended for the same purpose.! ° Structure and development—The humerus, like all the long bones, is only spongy at its extremities. It is developed from six points of ossi- fication ; one of which alone forms the body, one the head and the small trochanter, another the large trochanter, a fourth the inferior articular surface, a fifth the epicondyle, and the last for the epitrochlea, The latter is sometimes absent. FORE-ARM. _ This region has for its base two bones, the radius and cubitus (or ulna) united into a single piece at an early period.in most of the domesticated animals, 1. Radius. This is a long bone, placed in a vertical direction between the humerus and the first row of carpal bones, and divided into a body and two extremities. k Body.—Slightly arched and depressed from before to behind, the body presents for study two faces and two borders. The anterior face is convex and perfectly smooth. The posterior, a little concave from one extremity to “the other, offers: 1, Near the external border, a triangular surface, covered with asperities, elongated vertically, very narrow, commencing near the upper fourth of the bone and terminating in a fine point towards the lower fourth: this surface is brought into contact with the anterior face of the ulna by an interosseous ligament, which is completely ossified before the animal reaches adult age; 2, Above, there is a wide, transverse, but shallow groove, which aids in forming the radio-ulnar arch and shows, near the point where it touches the preceding surface, the nutrient foramen of the bone; '8, Near the internal border, and towards the inferior third, there is a ver- tically elongated and slightly salient eminence of insertion. The two borders, external and internal, are thick and rounded; they establish an insensible transition between the faces. . Extremities.—The superior is larger than the inferior. It has: 1, An articular surface elongated from one side to the other, concave from before to behind, wider within than without, and moulded to the articular surface of the inferior extremity of the humerus; there is also seen, outwardly, a double gorge which receives the two lips of the external trochlea; in the middle, an antero-posterior ridge which is received into the internal trochlea ; within, an oval cavity corresponding to the internal border of the former ; 2, The external tuberosity, placed at the extremity of the great diameter of - the articular surface; it is prominent and ‘well detached ; 3, The internal or bictpital tuberosity, a large, very rugged, and depressed process, situated within and in front of the glenoid cavity; 4, A little lower, and on the same side, there is a strong muscular and ligamentous imprint, separated from the preceding tuberosity by a transverse groove intended for the passage of a tendinous branch ; 5, The coronoid process,? a small conical eminence, at the summit of which terminates, anteriorly, the median ridge of the articular 1 The articular surfaces which, in veterinary anatomy, have received the names of trochlea and condyle, not being the same as in human anatomy, there results an annoying inversion of the situation of the epitrochlean and epicondyloid eminences, so named. It has therefore been our endeavour to remedy the improper employment of these denominations, which has been a cause of error in comparative anatomy. \ 2 In Man this belongs to the ulna. 76 . THE BONES. surface; 6, Two diarthrodial facets elongated transversely, cut on the posterior outline of the large articular surface, with which they are con Fig. 43. EXTERNAL FACE OF THE RADIUS AND ULNA. 1, Ulna; 2, Point of the ole- cranon; 3, Beak of the ole- eranon; 4, Radio-ulnar arch; Supero-external tuberosity ; 6, Radio-ulnar articular sur- faces for the humerus; 7, Bicipital tuberosity; 8, Shaft or body of the radius ; 9, Grooves for tendons, founded by their superior border ; they correspond to similar facets on the ulna; 7, Below these, a roughened surface which extends to the radio- ulnar arch, and is in contact with an analogous surface of the same bone through the medium of an interosseous ligament; in the Horse this liga- ment rarely ossifies. The inferior extremity, flattened from before to behind, ‘presents: 1, Below, an articular sur- face elongated transversely and somewhat irregu- lar, responding to the four bones in the upper row of the carpus; 2, On the sides, two tube- rosities for ligamentous insertion, the internal salient and well circumscribed, the other eaternal- and excavated by a vertical fissure, in which passes a tendon; 38, In front, grooves for the gliding of tendons; the external is the largest, and. vertical like the median; the internal, the nar- rowest, is oblique downwards and inwards; 4, Posteriorly, a strong transverse ridge which sur- mounts the articular surface and serves for the insertion of ligaments. Structure and development. The radius is a very compact bone, and is developed from three. centres of ossification: one for the body and two for the extremities. 2. Ulna. This is an elongated, asymmetrical bone, in the form of an inverted triangular pyramid, applied against the posterior face of the radius, to which it is united in adult solipeds. It offers for des-. cription a middle portion and two extremities. Middle portion —This has three faces wider above than below, and three borders which become joined at the inferior extremity of the bone. The. eaternal face is smooth and nearly plane. The internal is also smooth and slightly hollowed. The anterior is formed to correspond to the radius, and presents peculiarities analogous to those of the posterior face of that bone. Thus there is found in proceeding from above to below: 1, Two small diarthrodial facets ;1 2, A rough surface; 3, A transverse groove for the formation of the radio-ulnar arch; 4, A triangular surface, studded with rugosities, which occupies the remainder of the bone to its lower extremity. The lateral borders, external and internal, are sharp, and, like the anterior face, are in contact with the radius. The posterior border is concave, rounded, and thicker than the other two. _ Extremities.—The superior extremity comprises all that portion which exceeds the articular surface of the radius. It constitutes an enormous 1 It is represented in Man by the smaller sigmosd notch, THE ANTERIOR LIMBS. 77 process—the olecranon—flattened on both sides, and presenting: 1, An external face, slightly convex; 2, An internal excavated face; 8, An anterior border, thin and sharp superiorly, notched below to for mthe sigmoid cavity :! an articular surface concave from above down- wards, rounded from one side to the other, which corresponds with the humeral cavity, and is surmounted by a salient prolongation named the beak of the olecranon; 4, A con- cave and smooth posterior border; 5, The summit, a kind of thick roughened tuberosity which terminates the olecranon above, and into which are inserted the extensor muscles of the fore-arm. At its inferior extremity, the ulna ends, towards the lower fourth of the principal por- tion of the fore-arm,in an acute point, and sometimes by a small knob (capitulum ulnve). It is not rare to see it prolonged, especially in the Ass and Mule, to the inferior external tuberosity of the radius. This tuberosity then appears to belong to it, at least in part; and all that portion which is situated behind its vertical groove might be justly considered as belonging to the ulna. _ Structure and development.—The ulna con- tains much compact tissue, even in the region of the olecranon; it is also very solid. It is an imperfect bone, developed from two centres of ossification only, one of these being for the , apex of the olecranon. FORE-FOOT OR HAND. The anterior foot, or hand, is the region which presents the greatest differences when it is inspected in the various individuals of the animal series. Nevertheless, in all the mam- malia the constitution of the hand is funda- mentally the same, and may be divided into - three sections: the carpus, metacarpus, and phalangeal region. The hand is formed by five parallel or quasi-parallel rays that constitute the digits, each of which is effectively or virtually com- posed of two superposed carpal, a metacarpal, and three phalangeal bones, forming altogether the digit, properly so called. But this typical composition, established through the labours of MM. Joly and Lavocat, is rarely found to be realised in a complete manner. Fig. 44, RIGHT FORE-FOOT OF A HORSE. 1, Radius; 2, Groove for the an- terior extensor of the phalan-- ges; 3, Scaphdides; 4, Lunare, 5, Cuneiform; 6, Trapezium ; 7, Magnum; 8, Uncifurm; 9, Metacarpal; 10, Small meta- carpal; 11, Sesamoid bone; 12, Suffraginis; 13, Coronary; 14, Naviculars 15, Pedal; 16, Its ala. The following is what is presented in the hand of Man, who is the most 1 The greater sigmoid cavity of Man. 78 THE BONES. perfect pentadactylous type. The carpus is composed of eight bones, the metacarpus of five small, parallel, bony columns; the phalangeal region of five digits—thumb, index, medius, annularis, and auricularis, formed each of three phalanges, with the exception of the thumb, which has only two. In the domesticated animals, the constitution of the hand is more or less removed from this type, in consequence of abortive development, which diminishes either the number of rays, or the number of pieces composing these. Thus, in the Cat and Pig there are eight bones in the carpus; but in the Dog and Horse there are no more than seven; in the Ox and Sheep there are only six, for in them two or three bones are fused together. The metacarpus of the Dog and Cat has certainly five metacarpal bones, but the metacarpus of the Pig hasno more than four, that of the Horse three, and that of Ruminants only two. In the metacarpus of the Pig the fifth bone is not developed. In the Horse it is entirely absent; the fourth and first are independent, and the third and second are confounded to form a voluminous bone which has been named the principal (or large) metacarpal. In Ruminants, the fourth and fifth metacarpals are quite imperfect, the first being arrested in its development, and the second and third becoming consolidated as in the horse. Lastly, it is noted that the digital region of Carnivora has five digits, the Pig four, Ruminants two, and Solipeds only one. In the Pig, the thumb is undeveloped; in ruminants it is completely absent, and the first and fourth are represented by two small bones situated behind the metacarpo- phalangeal articulation; while in solipeds the single digit already mentioned results from the fusion of the auricularis and medius. From this preliminary synthetical exposition, it will be easy to understand the description of the bones composing the hand in solipeds. 1. Carpal Bones. The carpus forms the base of the hand. Situated between the inferior extremity of the radius and the superior extremity of the metacarpal bones, it is composed of several small bones joined to each other in the fresh state by extremely solid articular bands. Collectively, they form an almost quadrilateral mass in which may be distinguished two faces and four borders. The anterior face is slightly convex from side to side and irregular; it corresponds to the tendons of the extensor muscles of the metacarpus and phalanges. _ The postertor face is very unequal and converted, especially outwardly, me a groove in which the tendons of the flexor muscles of the phalanges glide. The superior border articulates with the radius; the inferior border with the metacarpal bones. _ The lateral borders are nearly level; above and behind the external border is remarked a considerable eminence, formed by the bone which will be hereafter studied as the supercarpal bone (or trapezium). In the carpus of the Horse are seven bones, which are disposed in two superposed rows. The superior row comprises four bones placed side by side, and designated by the numerical names of first, second, third, and fourth, viewing them from without to within. The inferior row has only three, which are named in the same manner, THE ANTERIOR LIMBS. 79 In applying to them the names proposed by Liser, we have, in the upper row: #1. The pisiform, or supercarpal bone (trapezium) ; $2. The pyramidal (or cuneiform) bone; — 23. The semilunar (or lunare) bone } 4, The scaphoid bone; In the inferior row: 7 1. The hook or unciform bone ; 6 2. The great bone or capitatum (magnum); ~ 5 3. The trapezoid bone. The description of these bones is most simple, and may be made in a general manner for all. Thus, with the exception of the supercarpal bone, they are solids, nearly cubical in form, and exhibit’ on their periphery : 1, Articular surfaces ; 2, Surfaces of insertion. The articular surfaces represent small, flat, or slightly-undulating facets, distributed on the superior, inferior, and lateral surfaces ; none are found in front or behind. The superior and inferior faces are entirely occupied by a single facet which responds either to the radius, the metacarpal, or to the bone of the other row. The lateral facets are always multiple and in contact with the bones of the same tier ; they do not exist, of course, on the eccentric side of the first and third bones of the superior or inferior rows. The surfaces of insertion are absent on. the superior and inferior faces; they separate, in the form of roughened fosse, the lateral articular facets. Before and behind they are covered by more or less marked rugosities. Bonzs or THE Upper or AntipracuiaL Row.—The first, or os pisiforme, is without the row; it is situated above and behind the carpus, from whence its name of supercarpal bone, by which it is usually known in veterinary anatomy. .This bone, which merits a special description, represents a disc flattened on both sides, offering for study two faces and a circumference. The external face is convex, roughened, and channeled anteriorly by a groove that traverses it from above to below, and in which glides the inferior tendon of the external flexor of the metacarpus. Its internal face, smooth and concave, concurs to form the external wall of the carpal sheath. The circumference presents, in front, two articular facets: the superior, concave, corresponds to the radius; the inferior, convex, is in contact with the second bone of the upper row. The other three bones of this row increase in volume from without to within. The second, or os pyramidalis (or cuneiform), responds to the radius, the first bone of the lower row, the third of the upper, and the supercarpal bone ; it has in all five articular facets. . . The third, or os semilunare (lunare), has six facets, and is united below to the first and second bones of the second row. 1 The analogue of the trapezium of Man is not found in the Horse. According to M. Lavocat, we ought to regard as such a small supernumerary bone sometimes seen articu- lating behind the third bone. We are entirely of his opinion. (Leyh jis also of this opinion, and states that this supernumerary bone is more frequently found in large common-bred horses. Stubbs, in his old, but fine ‘ Anatomy of the Horse, does not refer to it, but describes the seventh bone as the pisiform. Percivall says the supernumerary bone is not invariably present, and that sometimes two are found. He designates Stubbs’ and Chauveau’s pisiform bone as the trapezium. Girard nameg tie supernumerary bone the “pisiform” or pea-shaped. When one or more of these osseous nodules are present, they represent the pollex and fifth digit of the human hand.) 80 THE BONES. 3 : ly The fourth, or os scaphoides, the most voluminous of the row, has only. four ee and sriculates by its inferior face with the os magnum and ides. rE Collectively, the second, third, and fourth bones of the upper row form ticular surfaces. _ - ; ; : eee or radial articular surface, is very irregular; but in ex- amining it from without to within there may be observed: 1, A glenoid cavity on the pyramidal bone ; 2, In front, a transversely-elongated condyle Fig. 45. Fig. 46. POSTERIOR VIEW OF THE RIGHT FRONT VIEW OF RIGHT CARPUS. : CARPUS. 1, Second of upper row, or cuneiform ; 1, Second cuneiform, or pyramidalis; 2, 2, Third, or lunare; 3, Fourth, or Third, or lunare; 3, Fourth, or sca- scaphiides; 4, First, supercarpal, or phiéides; 4, First, supercarpal, pisiform, trapezium; 5, First of second row, or or trapezium; 5, First of lower row, unciform; 6, Second, or magnum; or unciform; 6, Second, or magnum; 7, Third, or trapezoides. 7, Third, or trapezoides; *, *, Small metacarpal bones, on the semilunar and scaphoid bones; 3, A groove placed behind the pre- ceding condyle. . _ The inferior articulating surface, which corresponds to the second row, is constituted by several undulated facets; it is convex outwardly and in front, concave posteriorly and inwardly. Bones or THE Inrerion on Mrtacarpan Row.—The thickness of these bones decreases from without to within. The first, uneiform, or hookbone (0s hamatum), has four diarthrodial facets, and responds, above, to the two first bones of the superior row; below, to the first and second metacarpals. : The second, os magnum, or os capitatum, the largest, has seven articular facets, three of which are on the interno-lateral face. It articulates, above, THE ANTERIOR LIMBS. with the" semilunar and scaphoides; below, and the internal rudimentary metacarpal. 81 with the principal metacarpal é The third, or trapezoides, the smallest, is provided with five facets, and is In contact with the scaphoides above, and the middle and internal meta- -carpals below. Collectively, these bones of the lower row form two large diarthrodial surfaces. The upper surface responds to the bones of the upper row, and is constituted in front, and from without to within, by a small condyle and two glenoid cavities; behind, by two isolated condyles, formed by the os magnum and the trapezoides. The inferior articular surface is only formed by more or less long and plane facets, which incline towards each other. It corresponds to the three portions of the metacarpus. Structure and development.—Hach carpal bone is formed by a nucleus of close spongy substance enveloped in a layer of compact tissue. . Hach is developed from a single centre of ossification. 2. Metacarpal Bones. In Solipeds, the metacarpus is composed of three bones, named the “ metacarpals,” standing parallel to each other. These are the principal metacarpal and the two rudimentary metacarpals, an external and. internal. Principat Mrtacarpat.—This is a long cylindrical bone, situated vertically between the carpus and the digital region. Body.—The body is a little depressed before and behind, a disposition which permits it to be described as having two faces and two borders. The anterior face is perfectly smooth and rounded from side to side. The posterior face is flat, and exhibits: 1, Towards the upper third, the nutritive foramen of the bone; 2, On the sides, two narrow, roughened surfaces, parallel and elon- gated. vertically, commencing near the superior extremity to disappear a little below the middle of the bone; these surfaces are held in apposition with the rudimentary metacarpals by means of an interosseous ligament which is often ossified in old horses. The borders, external and internal, are very thick, round, and smooth, like the an- terior face. : _ Extremities —The superior is flattened before and behind, and presents: 1, Above, an undulating articu- latory surface, formed by the union of several flat facets more or less inclined on one another: they respond to all the lower row of carpal bones; 2. An- teriorly and inwardly, a tuberosity for muscular inser- tion; 3, Posteriorly, and directly above the roughened POSTERIOR VIEW OF RIGHT METACARPUS. 1, Head of large meta- carpal bone for ar- ticulation with the trapezoides, mag- num, and unciform ; 2, Inner splint, or small metacarpal bone, for articula- tion with the trape- zoides; 4, Scabrous surface for the at- tachment of the sus- pensory ligament ; 5, Nutrient fora- men; 6, Median ridge separating the two inferior con- dyles. surfaces of the posterior face, four small diarthrodial facets in pairs, and running into the larger ‘articular surface by their superior border: they are adapted to similar facets on the rudimentary metacarpals. — corresponds to the first phalanx and the extremity, elongated transversely, The inferior large sesamoids by an articular surface, convex from before to behind, which 82 THE BONES. is composed of two lateral condyles separated by a median spine. The two condyles would be exactly alike, if the antero-posterior diameter of the external condyle was not less extensive than that of the opposite condyle. Both are hollowed on the sides by an excavation for the attachment of ligamentous fasciculi. . Structure and development—The principe’ metacarpal is one of the most compact bones in the body. It is developed from two centres of ossification, one of which is for the inferior extremity. Rupimentary Meracarpars.—The two rudimentary (small) metacarpal (or splint) bones are elongated, and placed against the posterior face of the principal bone, one without, the other within. Each is in the form of an inverted pyramid, and exhibits a middle part and two extremities. Middle portion.— Prismatic and triangular, this offers: 1, Three faces,—an external, smooth and rounded from one border to the other; an énternal, plane, and equally smooth; an anterior, covered with asperities to give attachment to the interosseous ligament uniting the lateral metacarpal bone to the median; 2, Three salient borders which markedly separate the faces from each other. Extremities —The superior, the largest, is named the head, and shows: above, a diarthrodial facet which corresponds to one or two bones of the inferior row of the carpus; in front, other two small facets continuous with the pre- ceding, and in contact with similar facets on the median metacarpal bone; on the other points of its periphery are rugosities for the attachment of ligamentous and tendinous fibres. The inferior extremity only reaches to about the lower fourth of the large metacarpal bone, and terminates in a small enlargement or button, which is never consolidated with the latter. The two lateral metacarpals, although very much alike, may yet be easily distinguished from each other. For instance, the internal bone is always the thickest and often the longest; besides, the superior articular surface of its head results from the union of the two facets corresponding to the two last carpal bones of the lower tier. Structure and development.—Of a somewhat compact texture, like all the long bones, these have no medullary canal, and are developed from only one ossific centre. Not unfrequently, however, the tubercle is formed from a special centre. 38. Bones of the Phalangeal Region or Digit. Solipeds have only one digit, supported by the principal metacarpal bone, and composed of three pieces placed end to end, one upon another. The first comprises three bones: a principal, the first phalanx, and two com- plementary ones, the sesamoids. The second is formed by the second phalanx, and the last, which terminates the limb, is constituted by the third phalanx and an accessory bone which has received the name of the small sesamoid (navicular bone). First (proxtmaL) on Meracarpat Paananx.—The first phalanx (or pastern bone), the smallest of all the long bones, is situated in an oblique ~ direction from above downwards, and behind to before, between the principal metacarpal and the second phalanx. : Body.—Depressed in front and behind, this bone exhibits: an anterior face, round from one side to the other, and slightly roughened above and below; a posterior face, flat, covered with ligamentous imprints in the form ofa triangle with the base reversed ; two lateral borders, thick, rounded, and provided with some imprints, THE ANTERIOR LIMBS. 8&3 Extremities —The superior, the largest, presents: Above i surface adapted to the inferior snetecatpal se and sonsequently el of two glenoid cavities separated by a groove running from front to ite laterally, and a little posteriorly, a well-defined tubercle of insertion. The inferior extremity has a transversely elongated articular surface to cor- respond to the second phalanx; this surface is formed by two condyles separated by a middle groove, and surmounted laterally by a small tuberosity for ligamentous insertions. The external condyle is smaller id Fig. 48. Fig. 49. LATERAL VIEW OF THE DIGITAL REGION 3 OUTSIDE OF RIGHT LIMB. 1, Large metacarpal bone; 2, 3, Outer and inner sesamoids ; 4, First, proximal, suffraginis or metacarpal phalanx, 5, Its posterior surface; 6, Tuberosity for ligamentous insertion; 7, Inner condyle of ditto; 8, Eminences on second pha- janx for attachment of lateral liga- ment; 9, Smooth surface for passage of deep flexor tendon on second pha- lanx; 10, Imprint for the insertion of the terminal branch of the perforatus tendon; 11, Navicular bone; 12, Third phalanx, pedal, or coffin bone; 13, Its basilar process. POSTERIOR VIEW OF FRONT DIGITAL REGION. 1, Large metacarpal bone; 2, 3, Outer and inner splint bones; 4, 5, Sesamoid bones; 6, Suffraginis; 7, 8, Tuberosi- ties for insertion of crucial ligaments ; 9, Triangular space for insertion of short sesamoid ligament; 10, Anterior face of suffraginis; 11, 12, Tuberosities for ligamentory insertion; 13, Articu- lar depression separating condyles; 14, 15, Second phalanx; 16, Scabrous sur- face for ligamentous attachment; 17, Smooth surface for gliding of deep flexor tendon; 18, Navicular bone; 19, Pedal bone; 20, Basilar process ; 21, Plantar foramen. than the internal, and when the bone is placed upon a horizontal plane, the anterior face turned upwards, it only touches by three points—the two tubercles of the upper extremity and the internal condyle; by pressing on the external condyle, it is easy to make the bone rock. The first phalanx is a very compact bone, and is developed from two points, one of which is for the superior extremity alone. 84 THE BONES. Susamors.—These are two small short bones placed side by side behind the superior extremity of the first phalanx, whose articular surface it completes, as it has not extent enough to be exactly adapted to the metacarpal surface. Each of these bones represents a small, irregularly- shaped polyhedron, or rather, a short trifacial pyramid. It otters : an anterior face, which is articular, and corresponding to the inferior extremity of the principal metacarpal bone, moulded, as it were, on one of the condyles and one of the sides of the median ridge; a posterior face, covered with cartilage in the fresh state, and forming, with that of the opposite bone, a gliding concave surface for the flexor tendons of the phalanges ; a lateral face, studded with ligamentous imprints; a summit, directed upwards ; and a base, turned downwards, and serving for the attachment of several ligaments. Seconp (on Mrippie) Paaranx (Os Corona, Smatu Pastern Bonz).— This is a short bone, situated in the same oblique direction as the first phalanx, and between it and the third. Its general form is that of a cube flattened before and behind, and offering the following features: an anterior face, covered with some slight imprints; a posterior face, provided, above, with a transversely elongated gliding surface; a superior face, channeled by two glenoid cavities, to match the inferior articulating surface of the first phalanx; an inferior face, formed on the same plan as the last, being occupied by two unequal condyles which articulate with the third phalanx and the navicular bone ; two laterul faces exhibiting a very marked imprint. In the interior of this bone is found a nucleus of very condensed spongy substance, enveloped in a layer of compact tissue. It is usually developed from a single centre of ossification; though in many subjects there is a complementary nucleus for the superior articular surface and the posterior gliding surface. Tarp (Disra) PHatanx, Os Pepis (orn Pepa Bonn).—This is a short bone which terminates the digit, and sustains the hoof’ that incloses it and the navicular bone. When completed by a special fibro-cartilaginous apparatus, it represents the segment of a very short cone, obliquely truncated behind, from the summit to the base. It offers for study: three faces, three borders, and two lateral angles Faces.—The anterior, convex from side to side, and cribbled by porosities and vascular openings, shows on each side: 1, The preplantar fissure, a horizontal groove more or less ramified, which commences behind, between the retrossal and basilar processes, ter- minating in front in one of the foramina which penetrate the bone; 2, The patilobe eminence, a roughened projecting surface, situated between the preceding fissure and the inferior border of the bone. The superior face is occupied by an articu- lar surface formed by two glenoid cavities and a slight median ridge ; it comes in apposition with PLANTAR surFacr or turrp the inferior face of the second phalanx. The PHALANX. inferior (or solar) face, hollowed out like an arch, 1, Lower face, or sole; 2, 3, is divided into two regions by the semilunar crest, Wings, or retrossal pro- a salient line which describes a curve forwards. pease’ internal. borders phe anterior xegion j f i 5, Plantar faremiine, an gion 1s perforated with very fine porosities, and corresponds to that part of the hoof named the sole. The posterior region shows, immediately behind the semilunar crest, a median imprint, and two lateral channels designated the Fig. 50. THE ANTERIOR LIMBS. 85 plantar Jissures. These originate at the root of the basilar process, are directed obliquely downwards and inwards, and open into the plantar jora- mana, the external orifices of two large canals which enter the bone and unite in its interior to form the semilunar sinus, Borders.—The superior describes a curve, with the convexity forward, and presents: 1, In its middle, the pyramidal eminence of the os pedis, a single triangular process, flat before and behind, roughened on its anterior aspect, and concurring, by its posterior surface, to form the articular surface which responds to that of the second phalanx, 2, Laterally, two facets of insertion which encroach on the anterior surface, and even advance, posteriorly, nearly to the preplantar fissure. The inferior border is thin, dentated, convex, and semicircular; it is perforated by from five to ten large foramina which pass into the bone. ‘The posterior border is slightly concave ; on it is observed a very narrow, transversely elongated, diarthrodial facet, which becomes confounded with the superior large articular surface, and is adapted to a similar facet on the navicular bone. Lateral angles.—These are two projections directed backwards, on whose summit the three borders of the bone unite, and which gives attachment to the later fibro-cartilages. A deep notch, the origin of the preplantar’ fissure, separates each into two particular eminences: one, the superior, named by M. Bouley the basilar process ; the other, the inferior, prolonged behind, and designated by Bracy Clark the retrossal process, from retro, behind, and ossa, bone. Structure.—The os pedis exhibits in its interior the semilunar sinus, a cylindrical, transversely elongated, and semicircular cavity resulting from the arching anastomoses of the two plantar carals. From this cavity pass off numerous channels, which anastomose frequently with each other, and open externally by the foramina on the anterior face of the bone, or by those on its inferior border. The os pedis has for its base a nucleus of spongy substance, surrounded by a layer of compact tissue. The latter is thicker towards the pyramidal eminence than elsewhere, and sends into the interior numerous prolongations which form the walls of the semilunar sinus, as well as the bony channels which spring from it. Development.—The third phalanx, formed from a single nucleus of ossification, undergoes numerous changes in its configuration during life. Thus, in the young animal the lateral angles are thick, obtuse, and but little prolonged posteriorly ; but as it grows older, they increase in length and become salient. The development they then assume is due to the progressive ossification of the lateral cartilages implanted on their surface. It often happens, in very old horses, that this ossifying process is carried to an extreme degree, and nearly the whole substance of these complementary organs is invaded. From the commencement, its inevitable result is to convert the notch which separates the basilar from the retrossal process into a foramen. : The complementary fibro-cartilaginous apparatus of the os pedis.—To understand properly the disposition of this portion of the foot, it is necessary that a previous knowledge of the ligaments and tendons attached to the os pedis should have been obtained ; therefore a detailed description will only be given when the Horse’s foot is studied as a whole. It will be svfiicient here to state that this apparatus consists of two lateral pieces, tho fibro- cartilages of the os pedis, united behind and below by the plantar cushion, a fibrous and elastic mass on which rests the navicular bone through the medium of the perforans tendon. 9 86 THE BONES. Tus Smatt Szsamorp (orn NavicuLar) Boyz.—This short bone is annexed to the third phalanx, behind which it is situated ; it is elongated transversely, flattened above and below, and narrowed at its extremities. It offers: 1A superior face, on which are prolonged the glenoid cavities and the median ridge of the articular surface of the os pedis; it responds to the second phalanx ; Fig. 51 2, An inferior face, divided by a é 9 . slight relief into two undulated / i sug facets, and covered with cartilage Cp La a to form a gliding surface; 3, An Wiis aS anterior border, channeled length- “% ways by a groove of insertion, above SAGTGUE AR BROWNE which is remarked a diarthrodial u, Upper, or articular surface ; b, inferior border ; facet that brings the small sesa- v, Superior border; d, Inferior, or posterior moid into contact with the pos- surface; e, The median transverse ridge; f, terior border of the third phalanx; Interior margin; g, Superior margin. 4, A posterior border and two ex- tremities, for ligamentous insertion. This bone, as well as the sesamoids, originates from a single centre of ossification. It is formed of a layer of compact tissue enveloping a nucleus of very condensed spongy substance. DIFFERENTIAL CHARACTERS OF THE ANTERIOR LIMB IN OTHER THAN SOLLPED ANIMALS. A, Suoutper.—In Carnivora the shoulder is composed of two bones, these creatures being furnished with a clavicle. This bone in the Dog is a little osseous shell inbedded among the muscles situated in front of the scapulo-humeral angle. That of the Cat constitutes a small styloid bone, which is jcined to the acromion and steruum by two ligamentous cords. In all the domesticated animals except Solipeds, the coracoid process is immediately applied against the glenoid cavity. In all, also, with the exception of the Pig, the scapular spine gradually rises from above to below, and terminates in a sharp salient point, the acromion. The spine partitions the external face of the bone into two equal fosse in the Dog, and in Ruminants into two fossee, which, for extent, are a3 one to three to each other. The scapular spine of the Pig is much elevated towards the middle part, and bends more or less backwards, In the Carnivora the prolonging cartilage is entirely absent; the anterior border of the scapula is very convex, as if the bone had bees curved downwards. In the other domesticated mammals the scapula is somewhat regularly triangular. B. Arm.—Proportionately, the humerus is longer, and more inflected like an S, as the number of apparent digits is increased. Therefore it is that in the Carnivora the characters of length and inflexion are most marked. In the Ux, Sheep, Pig, and Dog, the furrow of torsion is not so deep as in the Horse, and the deltoid imprint is less salient. In the Dog this imprint is represented hy a large roughened surface; in the Pig by some asperitics only. The nutrient foramen is on the posterior face, It has been stated that the medullary canal in the Ox is traversed by an osseous band; but the presence of this is not constant. : The summit of the trochiter 18 very elevated, particularly in Ruminants, and is thrown back on the bicipital groove, which is single; in the Dog and Pig, this groove is carried inwards above the internil face of the humerus. The external trochlea in the Ox and Pég is well marked. In Carnivora, the inner lip of this trochlea is very high, and the external lip incomplete; a foramen establishes communication between the olecranian and coronoid fosse. In the Cat there is found, on the inner side of the lower extremity, a particular foramen that forms a vascular arch. C, Fore-arm.—The fore-arm is short in the Ox, Sheep, and Pig; very long in the Carnivora. The principal differential characters that it presents are connected with the relative dimensions of the two bones and their mode of union. Regarding these, and as generally applicable, the following principles may be laid down :— 1. The development of the ulna is in direct relation to the division of the foot.—Mono- dactylous animal, such as the Horse, Ass, and Mule, have in fact only a rudimentary THE ANTERIOR LIMBS. 87 ulna. In the pentadactylous animals, as Man, the Cat, etc, on ane: the contrary, this is » veritable long bone which equals, or even Fig. 52, ’ exceeds, the radius in volume. : 2. The closeness of union between the radius and ulna is in increased proportion as the animal exclusively employs its inferior extremity for standing or walking.—Thus, in Solipeds and Rumi- nants, and Pachyderms in general, the two bones are consolidated or at least united, by an interosseous ligament, and in so firm a manner that they can only execute very obscure movements on each other. The anterior limb of these animals is indeed only used to support the body on the ground. In those, on the con- trary, which may employ it to dig up the soil, climb on trees, etc., ‘or as an organ of prehension, the radius and ulna are merely joined at their extremities by an articulation, which permits them to move upon one another with the greatest facility. Rodents, the majority of the Carnivora, and the quadrumana, are so provided ; but it is in Man that the relative independence of the two bones is carried to the highest degree. No animal can so easily execute the movements of pronation and supination of the hand, which are determined by the play of the two bones of the fore-arm on each other. To the indication of these fundamental characters may be added some details on a few particular and important points. _ In all the domesticated animals other than Solipeds, the ulna is developed from three ossifying centres, extends the whole length of the radius, and concurs to form the articular surface correspond- ing to the carpal bones. It is an elongated bone in Ruminants, and a long bone, hollowed by a medullary canal, in the Pig and Carnivora. The inferior articular surface of the bone of the fore-arm in , ~ Ruminants is cut obliquely from above to below, and from with- 4 out to within. In these animals we find the radius very flat from before to behind, the bicipital tuberosity scarcely noticeable, and two radio-ulnar arcades united externally by a deep fissure. The union of the two bones is more intimate than in the Horse, for the ossification always finishes by invading that portion of the inter- osseous ligament placed above the superior vascular arcade. In the Pig, the ulna is flattened from before to behind, and spread out on the posterior face of the radius, which it almost completely covers. Its olecranon is very prominent. In the Dog and Cat, the two hones of the fore-arm are nearly equal in volume, and are slightly crossed in an X fashion. The superior extremity of the ulna is thicker than its lower extremity; it is nearly the opposite of this in the radius. Movable on one another, these ‘bones only touch by their extremities, and to this effect offer: A Above, on the ulna, concave articular surface, the small sig- moid cavity, and on the radius a rounded hinge-like facet; 2, ‘Below, on the radius, a concave surface, and on the ulna a convex one. '‘D. Fore-Foor, on BAND.—1. Carpal bones.—The carpus of the Pig, like that of Man, contains eight bones—four in each of the rows. ‘The second bone of the upper row corresponds with the ulna, and to a small extent with the radius. In the bones of the lower ‘row, it is observed that the first corresponds with the two external ‘metacarpals, the second with the great internal metacarpal, the third with the preceding and the small internal metacarpal. The fourth, or trapezium, terminates inferiorly by a blunt point, and has no ‘relations with the metacarpal bones, because the thumb is entirely undeveloped in this animal. ‘1, Olecranon ; 2, Body of the ulna; 3, Body of the radius; 4, 5, 6, First, second, and third bones of the upper row of the carpus; 7, 8, First and second bones of the lower row ; oy, Rudimentary metacar- FORE-ARM AND FOOT pals; 10, Principal metacarpals; 11, External digit; 12, Internal OF THEOX; FRONT “digit. : VIEW. 88 THE BONES. In the Cat there are also eight bones. The second, or pyramidalis, of the upper row is very developed; it occupies all the external border of the carpus, and articulates with the ulna, the first bone of the second row, and the first metacarpal. The supercarpal bone, elongated, prismatic, and thickened at its extremities, offers in front two coalescing articular facets, one to correspond with the ulna, the other to join the pyramédalis, The bones of the inferior row decrease in thickness from the first to the fourth, and correspond: the first, to the first and second meticarpals; the second, to the metacarpal 3a FORE-ARM AND FOOT OF THE DOG; ANTERIOR FACE. 1, First digit; 2, Second digit; 3, Third digit; 4, Fourth digit; 5, Thumb; 6, 7, 8, 9, First second, third, and fourth bones of the lower row of carpal bones; 10, 11, First and second bones of the upper‘row; 12, Supercarpal bones 13, Body of the ulna; 14, Apex of the olecranon ; 15, Beak of the olecra- non; 16, Body of the radius, of the third digit; the third, to that of the fourth digit; the fourth, to the metacarpal of the thumb. In the Dog there are only seven bones, as the scaphoid and semilunar bones are united, but the general disposition is the same as that in the Cut. Lastly, in the Ox and Sheep the carpus is only composed of six bones: four in the upper row, and only two in the lower, where the os magnum and trapezvides are consolidated. The supercarpal bone has no groove for gliding, and the pyramidalis articulates with the radius and cubitus. The bones of the lower row only articulate with the principal metacarpal bone. (Professor Gobaux, in 1865, exhibited specimens which go to prove that of the two bones of the lower row in the carpus of Ruminants, the internal really represents two; so that these animals actually have seven carpal bones like the Horse.) 2. Metacarpal bones—Vhe number of metacarpal bones varies much in the domesticated animals :— In the Carnivora thereare. . . . . 5 Inthe Pigthereare. . . . . .. 4 In Ruminants thereare. . . . . . 2 The five metacarpals of the Dog and Cat articulate with each other, at their superior extremities, by lateral facets; they offer, at their inferior extremity, a condyle prolonged backwards by an articular surface resembling that of the Horse. The middle two are always longer than the two lateral. The smallest belongs to the fifth digit, or thumb, and is terminated inferiorly by a trochlea. The four metacarpals of the Pig articulate with each other, as in the Carnivora. The second and third are larger than the first and fourth. The fifth metacarpal is not developed. In Ruminants the metacarpal bones are two in number: a principal, which itself results from the consolidation of the second and third metacarpals, and another altogether rudi- mentary. The principal metacarpal is channeled on its anterior face, and for its whole length, by a deep vascular fissure—a trace of the primitive separation of the bone in two pieces. This fissure presents, inferiorly, the anterior orifice of a canal that completly traverses the bone. The posterior face is also marked by a very slight longitudinal groove. Tlie superior extremity exhibits, externally and posteriorly, « single diar- throdial facet for the articulation of the rudimentary meta- carpal. The inferior extremity is divided by a deep notch into two articular surfaces, which together resemble the single surface in the Horse; each corresponds to one of the digits; the external is always smaller than the internal. In the foetus, the two long bones that form the great metacarpal are simply laid together, and their medullary canals are sepa- rated from each other by the double partition which results from this apposition ; after their coalescence, however, the par- titions are completely destroyed by resorption, and in a short time there is only a single medullary canal for the entire bone. The rudimentary metacarpal is only a small osseous stylet, articulating, by a diarthrodial facet, behind and to the outside of the superior extremity of the principal metacarpal; it is sometimes absent in the Sheep and Goat. THE ANTERIOR LIMBS. 89 fan Digital Region.—In the domesticated animals the number of complete digits is as Carnivora. . . . . 5 Pig. 2... 4 Ruminants. . . . . 2 The five digits of the Dog and Cat are exactly analogous to those of Man. Thus, the external corresponds to the auricularis, the second to the annularis, the third to the medius, the fourth to the index, and the internal to the thumb.—The latter, very small. has only two phalanges and does not come into contact with the ground. Each of the first four is composed: 1, Of a first phulanx, to which are annexed two sesamoids; 2, A second phalanx, which yet represents a veritable long bone; 3, A conical phalan- gette, pointed, bent downwards, and hollowed at its base by a circular groove, in which is lodged the matrix of the claw. ‘The small sesamoid (or navicular bone) is absent, but is replaced by a prominence of the ungual phalanx. The auricularis and index are alike, and not so long as the annularis and medius, which are the same in length. The Pig has four complete digits articulating from the metacarpals; the thumb is absent. The index and auricularis, or fourth and fifth digits, are short, and do not usually rest on the ground. Ruminants certainly possess four digits, but only two are perfect—the medius and annularis—and. these articulate with the inferior extremity of the principal metacarpal. The two others—the index and awuricularis - are in a rudimentary condition, and are represented by two small.bones situated above and behind the metacarpo-phalangeal articulation. __ In the Oz, Sheep, and Goat, each of the perfect digits comprises three phalanges and three sesamoids. The first phalanz fairly represents the moiety of the phalanx in the Horse. It has no posterior imprints, but shows them on its inner surface us for the attachment of several ligaments. This internal face is plane, and the external convex; these characters are repeated in the other two phalanges. It is also remarked in all the plia- langeal bones, that the external articular facet of the extremities is always larger than the internal, Of the two sesamoids, the external is larger and less elongated than the internal. first particulate witi each other, and with the They halanx by small diarthrodial facets. The second phalanx is hollowed internally by a small medullary cavity. The ungual phalanx, as a whole, resembles one of the lateral moieties of the os pedis of solipeds. This phalanx has no complementary fibro-cartilage, basilar process, or retrossal emi- nence, nor yet a cavity of insertion on the sides of the pyramidal eminence. The semilunar crest is replaced by an obtuse, thick, and rugged relief, which occupies quite the posterior limit of the inferior face of the bone. Three large 7 canals penetrate the third phalanx, two to the woman sCAPULA; EXTERNAL ASPECT. base of the pyramidal eminence, and one towards the origin of the preplantar fissure. They form, in the interior of the bone, a vast sinus, giving rise to several vascular canals which open on the surface. There is only one foramen at the base of the pyramidal eminence in thesmaller Ruminants. Fig. 54, a. {)))) 2), am IS 1, Supraspinous fossa; 2, Infraspinous fossa; 3, Superior border; 4, Supra- scapular notch ; 5, Anterior or axillary border ; 6, Head of the scapular and glenoid cavity; 7, Inferior angle; 8, Neck of the scapula; 9, Posterior border; 10, Spine; 11, Triangular COMPARISON OF THE THORACIC LIMB OF MAN WITH smooth surface, over which the tendon THAT OF THE DOMESTICATED ANIMALS. of the trapezius glides, with the tuber- i it and A. Suoriper.—The shoulder of man (fig. 54) culum spina scapula between it an has for its base two well-developed bones, the 103 12, Acromion process; 13, Nutrient scapula and clavicle. The scapula is more dig- foramen, 14, Coracoid process. tinctly triangular than that of all the domesti- ; r ' cated animals; its vertebral border is also more extensive. The scapular spine, very 90 THE BONES. elevated, is followed by an acromion who humeral articulation. The latter is separa constriction called the pedicle of the acromion. resembles a semi-flexed finger. The clavicle e it is flattened above and below, and flexed n the male than the female. clavicle is more pronounced i like an italic S. se extremity reaches to above the. scapulo- ted from the remainder of the spine by a The cvracoid process is voluminous, and xtends from the acromion to the sternum ; This inflexion of the B. Anw.—The humerus of Man is much longer than that of animals. Its diaphysis is prismatic and divisible into three faces; the deltoid imprint has the form of a V with its point directed downwards, The voluminous articular head is turned inwards; the Fig. 55. RIGHT HUMAN HUMERUS; ANTERIOR SURFACE, 1, Shaft; 2, Head; 3, Neck; 4, Greater tuberosity; 5, Lesser tuberosity ; 6, Bici- pital groove; 7, Interior bicipital groove ; 8, Posterior bicipital ridge; 9, Rough sur- face for insertion of deltoid; 10, Nutrient foramen; 11, Eminentia capitata; 12, Trochlea; 13, External condyle; 14, In- ternal condyle; 15, External condyloid ridge; 16, Internal condyloid ridge; 17, Fossa for the coronoid process of ulna. Fig. 56. HUMAN ARM-BONES; FRONT VIEW. j 1, Shaft of ulna; 2, Greater sigmoid notch; 3, Lesser sigmoid notch; 4. Ole- eranon process; 5, Coronoid process; 6; Nutrient foramen; 7, Ridges for inser- tion of interosseous membrane; 8, Capi- talum ulne; 9, Styloid process; 10, Shaft. of radius; 11, Its head; 12, Its neck; 13, Its tuberosity; 14, Oblique line; 15, Lower end of bone; 16, Styloid process.. , bicipital groove is single, and looks outwards. The inferior arti that of animals, expert that the condyle is more distinct. siete aca C. Forz-arm.—The two bones of the fore-arm, as we have already seen, only articu- late by their extremities; they are separated from one another in their middle part. The superior extremity of the radius corresponds to the condyle of the humerus; that of the ulna articulates with the humeral trochlea. The coronoid process belongs to the ulna. At the lower extremity of the fore-arm it is remarked: 1, That the radius cor- responds to the greater portion of the carpus, while the ulna only articulates with the pyramidalis; 2, That the radio-carpal articulation is protected outwardly and inwardly by two small osseoug prolongations, the styloid processes of the ulna and radius. D. Hanp.—1. Carpus.—The carpus of Man is composed of eight bones—four in-each THE POSTERIOR LIMBS 91° row. The three first of the upper row articulate with the radius; the fourth responds to the ulna, In the bones of the lower row, the trapezium responds to the metacarpal of the thumb and that of the index. the trapezoides tu the latter only, the os magnum and uuciform to the metacarpals of the medius, annularis, and little finger. “The pisiform bone and the cuneiform process of the unciform convert the posterior face of the carpus into a channel. 2. Metacarpus.—The five metacarpals of Man are parallel to each other, and articulate by their superior extremities with the bones of the car- pus; by their inferior extremities with the phalanges. They are all concave in their middle portion, and thickened at their ends. The metacarpal of the thumb is the shortest and strongest. The others diminish in volume from the fourth to the first. 3. Digital RegionHere we find five digits, each composed of three bony columnettes, with the exception of the thumb, in which only the second and third pha- langes are present. They decrease in length from the third to the first, and the third to the fifth. The first and second phalanges are small semicylindrical bones, slightly thickened at their extremities. The ungueal phalanges are constricted in their middle, and widened like a horse-shoe at their inferior extremity; the palmar face is roughened, the dorsal face smooth. ARTICLE V.—PostTERIor Limes. Each of these is divided, as already noted, into four secondary regions: the pelvis, thigh, leg, and foot. PELVIS, The pelvis is a kind of bony cavity formed PALMAR SURE ACE OSULEND by the union of the sacrum with two lateral a : 5 . +41, 1, Scaphoid bone; 2, Semilunare; pieces, the coxw, which are-consolidated with “’s “Cuneiform; '4, Pisiform; 5, each other in the inferior median line. The Trapezium 5 6, Groove in tia description of the sacrum having been already pezium for tendon of flexor iven, it now remains to speak of the coxa. carpi radialis; 7, Trapezoides s BAYER P 8, Magnum ; 9, Unciform ; 10, A. Coxa 10, The five metacarpal bones; 11, 11, First row of phalanges ; The coxa, also designated os liacum, os inno- 12, 12, Second row; 13, 13, eas is a very irregularly-shaped flat bone, fae We Eee et ouble (with its fellow on the opposite side), jast phalanx, > and directed obliquely from above to below and before to behind.: It is contracted in its middle part, which presents exter- nally an articular cavity, the cotyloid ; anteriorly, where it rests on the sacrum, it becomes widened, as it also does in its posterior portion, which is inflected inwards to be united, on the median line, with the bone of the opposite side. It is divided, in the foetus, into three distinct pieces, joined by cartilage in the centre of the cotyloid cavity, which the three concur in forming. Although they soon become consolidated into a single piece, it is customary to describe them as so many separate bones by the names of ilium, pubis, and ischium. In1um.—The ilium, a flat and triangular bone, curved on itself, directed obliquely from above to below, before to behind, and within outwards, forms the anterior portion of the coxa which corresponds with the sacrum. It is the most considerable of the three divisions, and has two faces, three borders, and three angles. 92 THE BONES. Faces.—The external or superior face, studded with some muscular imprints, is excavated on both sides, and is named the eaternal iliac fosssa, The internal or inferior face offers for study: 1, An external portion, smooth, and crossed by some vascular grooves; this is the iliac surface, which is replaced in Man by an excavation called the internal iliac fossa ; 2, An internal portion, roughened and uneven, presents, posteriorly, the auricular facet, an irregular diarthrodial surface, elongated from side to side, a little oblique in front and inwards, and responding to an analogous surface on the sacrum. ; Borders.—The anterior border, or crest of the ilium, is slightly concave, Fig. 58. THE COX; SEEN FROM BELOW. 1, liae surface; 2, Auricular facet; 3, Angle or crest of the ilium; 4, Angle of the haunch; 5, Cotyloid cavity; 6, Its bottom; 7, One of the imprints for the insertion of the anterior straight muscle of the thigh (rectus femoris) ; 8. Nio-pectineal ridge, 9, Channel on the external face of the pubes ; 10. Oval (or obturator) foramen; 11, Ischial spine; 12, 12, Ischial arch. pee te and bears a roughened lip for muscular insertion. The external border is thick, concave, and furrowed by vascular fissures ; it presents, inferiorly, the nutrient foramen The internal border is thin and concave ‘particularly in its posterior part, which constitutes the great ischiatic notch. ; . Angles. —The external angle, or anterior and superior spinous process, is thick, wide, and flat, and bears four tuberosities: two superior andtwo inferior. The internal angle, or posterior and superior spinous process, represents ® rugged tuberosity curved backwards and upwards’ ; The (! At the external angle of the ilium, there is sometimes found in the horse a process— often a very marked one—directed downwards, and completely enveloped by the external ilio-femoral muscle.) . ; ‘ ‘ THE POSTERIOR LIMBS. 93 posterior or cotyloid angle is prismatic and very voluminous. It exhibits: 1, Behind, a wide concave articular facet, which forms part of the cotyloid cavity; 2, Above this cavity, the supracotyloid crest, represented in Man by the ischiatic spine. This is an eminence elongated from before to behind, sharp on its summit, smooth inwardly, roughened outwardly, and continuous by its anterior extremity with the internal border of the bone; 38, Outwardly, two deep imprints for the insertion of the rectus muscle; 4, In front and inwards, the ilio-pectineal eminence, a small elongated pro- minence forming the most salient point of a kind of ridge (linea ilio-pectinea) that insensibly subsides above on the inner face of the ilium, and is continued below by the anterior border of the pubis. Of the three angles of the ilium, the first is also termed the angle of the haunch, and the second the angle of the croup. Pousis,—Situated\petween the ilium and ischium, elongated from side to PELVIS; FRONT VIEW. 1, Crest and anterior spinous process of the ium; 2, Angle of the croup, with the auricular facets proceeding from it ;, 3, Shaft of the ilium, with the ilio-pectineal crest ; 4, Cotyloid cavity; 5, Symphysis pubis; 6, Ischiatic tuberosity. side, flattened above and below, and irregularly triangular, the pubis, the smallest of the three divisions, is divided for convenience of description into ‘iwo faces, three borders. and three angles. : ; Faces.—The superior, smooth and concave, concurs in forming the floor of the pelvis. It shows one or two nutrient foramina. The inferior is roughened, and marked throughout its length by a wide channel which reaches the bottom of the cotyloid cavity. This fissure lodges the pubio- femoral ligament and a very large vein. ; a Borders.—The anterior is constituted by a thin rugged lip, which is curved upwards. The posterior, thick and concave, circumscribes anteriorly a wide opening, the oval, subpubic, or obturator foramen ; it is channeled near the cotyloid angle by a fissure which runs obliquely inwards and down- wards. The internal is united with that of the opposite pubis to form the pubic portion of the pelvic symphysis. t 94 THE BONES. Angles—The external, also named the cotyloid angle, is the thickest of the three. To it chiefly belongs the rugged depressed surface that constitutes the bottom of the cotyloid cavity. ‘The internal unites with the analogous angle of the opposite pubis. The posterior is consolidated at an early period with the antero-internal angle of the ischium, to inclose, inwardly, the oval foramen. ; ; Iscu1um.—This is the mean, in volume, of the three pieces of the coxa. Situated behind the pubis and ilium, it is flattened above and below, and of a quadrilateral form. It offers for study: two faces, four borders, and four angles. Faces.—The superior is smooth and nearly plane, and forms part of the floor of the pelvic cavity. It has a small nutritious foramen directed out- wards. The inferior presents some rugosities clustered particularly about mphysis. ee Fig. 60. PELVIS; LATERAL VIEW. 1, Crest of the ilium; 2, Angle of the croup; 3, Shaft of the ilium ; 4, Cotyloid cavity, or acetabulum, 6, Ischial spine, Borders.—The anterior, thick and concave, circumscribes the oval foramen posteriorly. The posterior, straight and directed obliquely forwards and inwards, forms, with the analogous border of the opposite bone, a large notch named the ischiatic arch. It exhibits, throughout its extent, a rugged depressed lip (the spine), arising from the side of the inferior face. The eax- ternal, thick and concave, constitutes the lesser ischiatic notch. The internal is joined to the ischium of the other side to constitute a portion of the pelvic symphysis. Angles—The antero-external or cotyloidean is the most voluminons ‘of the four, and affords for study: 1, An excavated diarthrodial facet, making part of the cotyloid cavity ; 2, The posterior extremity of the super-cotyloidean crest, limited by a small transverse fissure which separates it from the external border of the bone. The antero-internal angle is consolidated with the posterior angle of the pubis. The postero-external angle forms the ischiatic tuberosity. This is a large prismatic process which looks upwards, and is prolonged by a salient ridge, elongated from before to behind, with its sharp border turned outwards and downwards, The postero-internal angle THE POSTERIOR LIMBS. 95 forms, with that of the other ischium, the summit of the triangular space which constitutes the ischiatic arch, or pubic arch of some species. _ THe Coxa In GenERAL.—The bone whose three constituent parts we have just been studying, presents for consideration, as a whole, a middle portion and two extremities. The middle, very much contracted, offers, outwards and downwards, the cotyloid cavity (or acetabulum), which has not yet been described, because its study does not properly pertain to either of the three regions of the coxa. This cavity is intended to receive the articulating head of the femur, and represents the segment of a hollow sphere; it is cireum- scribed by a very salient rim which is thin at its free margin and widely notched on the inner side. The deeper portion is occupied by the rough- ened and depressed surface already designated as the bottom of the cotyloid cavity (fundus acetabuli), and which communicates by the internal notch of the rim with the inferior groove of the pubis. The anterior extremity, flattened on both sides, and formed by the ilium, rests, as has been shown, on the sacrum. The posterior extremity, flattened in an inverse sense to the preceding, is constituted by the pubis and the ischium, and traversed, from above to below, by the sub-pubic (or obturator) foramen, the large oval aperture which separates these two bones from one another, and perforates the floor of the pelvis; this opening is closed in the fresh state by muscles. The two coxe, by uniting in their posterior part, form the articulation to which has been given the name of ischio-pubic or pelvic symphysis ; thus united, the two bones represent something like a V with the opening in front; a circumstance which makes the lateral diameter of the pelvis greater in front than behind. SrructuRE AND DEVELOPMENT or THE Coxa.—To the three centres of ossification which constitute the coxa, are added two complementary centres: one for the anterior spinous process and spine of the ilium, another for the ischiatic tuberosity. In youth, the different parts of the coxa are very thick, and the spongy tissue is abundant, while the compact is rare. The pubis is always convex on its two faces, and the middle part of the coxa-—that adjoining the cotyloid cavity—is of considerable thickness, a feature which much diminishes the extent of the pelvic reservoir. As the animal advances in age, however, the layers of compact tissue increase in thickness, approaching each other as the spongy substance is lessened. The pubis becomes thinnest, and at an advanced period of life is sometimes even translucid. The compact tissue is always abundant in the neighbourhood of the cotyloid cavity, as this is the centre on which converge all the impulsive efforts communicated to the trunk by the posterior limbs. It is also in this cavity that ossification commences. B. The Pelvis in General. 1. Exrervat AND Internat Conformation or THE Petvis.—The pelvis is a kind of rear cavity in the form of a cone, which prolongs the abdominal cavity. Tt occupies the posterior part of the trunk, and with regard to its conformation, presents for study an external and an internal surface. External surface.—This may be resolved into four regions or faces. The superior region is slightly oblique from above to below, and before to behind; its degree of obliquity varies. It is contracted from before to behind, and shows: 1, On the median line, the spinous processes of the sacral and the first coceygeal vertebre ; 2, On each side the sacral grooves, at the bottom of which open the supersacral canals. 96 THE BONES. The inferior region is nearly horizontal. Formed by the pubes and ischia, it presents from before to behind: 1, In the middle, the ischio-pubie symphysis; 2, On each side the subpubic groove, the oval foramina, and the inferior face of the ischia ; 3, Quite externally, the cotyloid cavities, by which the pelvis rests on the posterior limbs. vs The lateral regions are oblique from above to below and within to without, and wider in front than behind. They exhibit: 1, The spine of the ilium and the two anterior spinous processes; 2, The external iliac fossa; 3, The ischiatic arch; 4, The supercotyloid crest or ischiatic spine, which presents outwardly the surface of insertion for the internal or deep gluteus muscles; 5, The lesser ischiatie notch ; 6, The ischiatic tuberosity. In'ernal surface.—The internal surface of the Horse’s pelvis cannot be divided into two portions as in Man, because the inner aspect of the iliac bones is not hollowed out to form an anterior cavity. The pelvis of Solipeds is, therefore, a simple conoid cavity, in which are dis- tinguished four regions or faces, and two apertures called the inlet and outlet. The anterior opening or inlet is nearly circular, especially in the Mare, and a little oblique downwards and backwards. It is limited above by the inferior face of the base of the sacrum; inferiorly, by the anterior border of. the pubis; and on the sides by a portion of the inner face of the iliac bones, and algo the internal aspect of the pectineal crests. The inlet presents four diameters: a vertical, horizontal, and two oblique. The first extends from the inferior face of the sacrum to the anterior border of the pubic symphysis; its mean length is 84 inches. The second is measured from one pectineal crest or eminence to another ; the mean of this is 8,2; inches. The two last diameters are estimated from she inferior face of the sacro-iliac articulation of one side to the ilio-pectineal eminence of the other; this is on an average 8, inches. These measurements irrefutably demonstrate that the inlet is not elliptical in the vertical direction. The posterior aperture or outlet, situated at the posterior end of the pelvic cavity, gives exit to the rectum and genital organs. As the pelvis of the horse is horizontal, the outlet should be considered as limited, we think, by the inferior face of the summit of the sacrum, the superior face of the ischia, the supercotyloid crest or ischiatic spine, and the internal face of the sacro-ischiatic ligaments. At the outlet only two diameters are recognised : a vertical anda horizontal. The vertical measures on an average 6; inches; it extends from the inferior face of the sacrum to the superior face of the ischial symphysis. The horizontal diameter, comprised between the two supercotyloid crests, is 71% inches. The superior region of the pelvic cavity is a little concave from before to behind; it has for base the sacrum, which presents on each side of the median line the subsacral foramina. This part is also called the sacral plane or roof of the pelvis. The inferior region, or ischio-pubic plane, is formed by the pubis and the ischia. It is concave from side to side; its anterior border is nearly straight, and its posterior border is scooped out by a wide notch to form the arch of the ischium. It has been remarked by M. Gobaux, that the portion of this plane corre- sponding to the pubis presents numerous varieties. The superior face of the pubis may be convex in its anterior moiety and concave in its posterior ; or it may be concave before and convex behind, the concavity being separated from the convexity by a transverse ridge. This ridge is sometimes represented by a series of small conical eminences, at other times this upper face is THE POSTERIOR LIMBS. 97 disposed as a smooth inclined plane, directed backwards and upwards, and a kind of rim surmounts the anterior contour of the oval foramen. With regard to the lateral reyions, they are formed by a small portion of the inner face of the ilia, and in great part by the sacro-sciatic ligaments. 2. Dirrerenors tn tHE Privis or tHe Suxes—The pelvis of the Mare exceeds that of the Horse in all its dimensions, but the difference is most marked in the transverse diameters. The anterior inlet forms a vast circumference when compared with that of the male ; the pectineal crests are widely apart, and the distance separating the anterior border of the pubis from the lower face of the sacrum is considerable. If the pelvis be viewed in its superior plane, it is found that in the Mare the ischiatic notches are very deep; that the internal border of the ilium forms @ regularly curved and very concave line ; and that the supracoty- loid crests, or ischiatic spines, are widely separated from each other. It is also noticed that the floor of the pelvis is wide, and that the bones com- posing it tend towards the same horizontal plane. In the male, the ischiatic border is only represented by a very curved line; this line is composed of two almost straight portions, which join at an obtuse angle at the origin of the neck of the ilium; the supracotyloid crests are relatively near each other, and bent towards the longitudinal axis ; while the two moieties of the pelvic floor are directed very obliquely down- wards and inwards. In the Mare, the ischial arch is larger than in the male, and forms a regular curve uniting the two tuberosities of the same name. In the Horse, the two ischiatic tuberositics are but little apart from each other, and the ischial arch forms a somewhat acute angle whose borders are nearly straight. Lastly, when the pelvis is examined in its inferior plane, in addition to the features already indicated in the ischiatic arch, it is found that in the Mare the obturator foramina are large and nearly circular, while in the Horse they are elliptical ; the cotyloid cavities are also further removed from the ischio-pubic symphysis in the female than the male. ‘The sacrum of the Mare has appeared to us, in some individuals, to be a little more arched from before to behind than that of the Horse; but this character is not constant. The following figures relating to the capacity of the pelvis in the Mare and Horse confirm what has just been enunciated. MARE, HORSE. Horizontal Diameters. Horizontal Diameters, Between the Pectineal | Between the Supercoty- | Between the Pectineal | Between the Supercoty- Crests. loid Crests, Crests. loid Crests. Inches. Inches. Tnches, tach; 9% a: Str Gi MARE. HORSE. Vertical Diameters. Vertical Diameters. Between the Sacrum and’ Between the Sacrum and Between the Sacrum and} Between the Sucrum and Pubis. | Ischium. | Pubis. Ischium. Inches. Inches, Inches, Inches. 8% 6% 8 6% -98 THE BONES. To recapitulate, there is observed in the pelvis of the Mare: . A great increase in the transverse diameters ; . A deep and regularly concave ischiatic notch 5 . A wide and concave ischial arch ; . Cireular obturator foramina; . The cotyloid cavities distant from the pubic symphysis. Oc 09 DD THIGH. This has for its base one bone, the femur. Femur. The femur is a long, pair bone, situated in an oblique direction down- wards and forwards, between the coxa and the principal bone of the leg; it is divided into a body and two extremities. Body.—It is irregularly cylindrical, and presents for study four faces, The external, internal, and anterior, confounded with one another, are regularly rounded and almost smooth, showing only some slight imprints and vascular grooves. The posterior, nearly plane, and wider above than below, offers: 1, Outwardly and towards the superior third, an uneven circular surface ; 2, On the same level, and inwardly, a slight crest, oblique downwards and outwards; 38, In the middle, a very extensive roughened surface, having the form of an obliquely angular parallelogram, for the attachment of the great adductor muscle of the thigh; 4, Below this surface, a large vascular groove running obliquely outwards and downwards. On the limit of the posterior and external faces are found, towards the upper third, a large rugged, flattened eminence, curved in front, and termed the subtrochanterian crest fe of its position under the trochanter ; below, a deep fossa, named. the’ ondyloid, garnished at its bottom with asperities and bordered in front by an uneven lip. On the limit of the posterior and internal face, there is observed from above to below: 1, The small trochanter, a large scabrous tuberosity, elongated in conformity with the bone, and situated near its upper fourth; 2, A marked longitudinal imprint for the attachment of the pectineus; behind, it is confounded with the surface for the insertion of the great adductor muscle of the thigh, and presents, in front, the nutrient foramen of the bone; 8, The origin of the great posterior fissure ; 4, Quite below, a collection of large tubercles which form the supracondyloid crest. Eutremities—The superior eatremity is sensibly flattened before and behind, and shows: 1, Inwardly, an articular head which is received into the cavity of the acetabulum. This head is separated from the other portion of the body by a neck, which is, however, not well marked in the Horse, and forms two-thirds of a sphere, excavated in its internal part by a very deep cavity for ligamentous insertion , 2, Outwardly, a very large eminence, the trochanter, or great (external) trochanter, in which is recognised, as in the trochlea of the humerus: a summit, much more elevated than the articular head and slightly bent inwards; a convewity, incrusted with cartilage and anterior to the summit, from which it is separated by a narrow ang deep notch; a crest situated under the convexity, and formed by a tuberculous surface on which one of the tendons of the middle gluteus muscle becomes * This is the third trochanter of Cuvier, and takes the place of the external and superior branch of the Linea aspera of Man, (It ig the i ‘Gosienken : Percivall and the middle troehanter of Leyh.) : Crete einer Re . THE POSTERIOR LIMBS. 99 inserted, after gliding over the convexity ; i id: y; 3, Posteriorly, the fossa th trochanter, or digital fossa, a deep cavity studded with ee an ate cae i ayes be by a salient lip which descends vertically from the it of the trochanter to the posteri re i me ere posterior face of the bone, where it The inferior extremity is flattened on both sides; con i > Q ; sequently, its 1 axis crosses at a right angle that of the upper extremity. it is dednauicted Fig. 61. Fig. 62. LEFT FEMUR; ANTERIOR VIEW. LEFT FEMUR; POSTERIOR VIEW. 1, Head; 2, 2, Trochanter major, with its 1, Head; 2, Great trochanter; 3, Third, or crest; 3, Trochanter minor externus, sub- trochanter minor externus; 4, Lesser, or trochanterian crest, or third trochanter; internal trochanter; 5, Fossa for insertion 4, Lesser, or internal trochanter; 5, Notch of ligamentum teres; 6, Trochanterian for insertion of ligamentum teres; 7, 8, fossa; 7, 8, Tuberosities; 9, Fossa for the Tuberosities for tendinous and ligamentous insertion of the external meniscus; 10, ' insertion ; 9, Trochlea. Supracondyloid fossa; 11, Condyles. py the presence of two condyles and a trochlea. The two condyles, placed one beside, the other behind, correspond to the superior extremity of the tibia. They are separated by a deep depression designated the intercondyloid fossa, which lodges the spine of the tibia and the interosscous ligaments of the femoro-tibial articulation. The external condyle bears outwardly two fosse: one superior, for ligamentous insertion; the other, inferior, for muscular 100 THE BONES. attachment. The internal condyle presents, posteriorly and inwardly, near the posterior extremity of the intercondyloid notch, a roughened depression for the insertion of the fibro-cartilaginous meniscus interposed between the external condyle and the corresponding articular plane of the tibia. It is surmounted outwardly, ic, on the side opposite to the intercondyloid notch, by a large tubercle of insertion, The érochlea, a wide pulley on which the patella glides, is situated in front of the condyles. It is slightly oblique downwards and inwards, and appears to continue in front the inter- condyloid notch. Of the two lips which border its cavity laterally, the internal is the thickest and the most prominent. Bag Pe Between the external and the corresponding con- dyle is seen a digital fossa for muscular insertion. Structure and development.—The femur, very ‘spongy at its extremities, is developed, from four principal centres of ossification: one for the body, another for the articular head, the third for the trochanter, and the last for the inferior extremity alone. LEG. This has for its base three bones: the tibia, peroneus (or fibula), and the rotula (or patella), 1. Tibia. , The tibia is a long, prismatic bone, thicker at the superior than the opposite extremity, and situated between the femur and the astragalus, in an oblique direction downwards and backwards, constituting the principal portion of the leg. SS : Body.—This offers for study three faces and pt | three borders. The faces are wider above than SECTION OF LEFT FEMUR, below. The external is almost smooth, and is SHOWING ITS STRUCTURE. Concave in its superior part and convex below, where it deviates to become the anterior. The internal, slightly convex on both sides, presents, superiorly, deep imprints tor the attachment of the adductor muscles of the thigh and; the semi- tendinosus. The posterior, nearly plane, is divided into two triangular surfaces: one, superior, slightly roughened, serves for the attachment of the popliteus muscle ; the other, inferior, much more extensive, is furrowed into numerous longitudinal crests which give attachment to the perforans “muscle. On the limit of these two surfaces is remarked the nutrient foramen of the bone. The borders are distinguished as anterior, external, and internal, The first is rounded, and not very salient in its inferior two-thirds; it forms in its superior third, a curved crest, with the concavity external, which joins the anterior and superior tuberosity of the bone; this has received the name of the tibial crest. The ewternal border is very thick and concave above, where it constitutes, in common with the fibula, the utbial arch. The imternal is also very thick, straight, and provided superiorly with some salient tubercles to which the poplitcus is attached. Extremities.—The superior extremity, the most voluminous, is formed by three tuberosities, an anterior and two lateral, which are external and internal, The first, the smallest, is a rugged process continuous with the tibial crest, and separated from the external tuberosity by a wide and THE POSTERIOR LIMBS. 101 deep groove in which passes a tendinous cord; it is excavated, in front, by a vertically elongated fossa which lodges the middle ligament of the patella, The external tuberosity, medium in size and the most detached, has outwardly an articular facet for the head of the fibula. The internal tuberosity, the largest and least detached, presents: on the sides, ligamentous imprints; behind, a small tubercle which gives attachment to the pos- terior crucial ligament of the femoro-tibial articu- lation. The superior face of the two lateral tube- rosities is occupied by two large irregular and undulated articular surfaces, which respond to the condyles of the femur through the medium of the two meniscus-shaped fibro-cartilages interposed be- tween the two bones. Of these two surfaces the external is always the widest, because it serves, by its posterior part, for the gliding movements of the popliteal tendon. They are separated from each other by the tibial spine, a conical articular eminence divided into two lateral parts by a groove of inser- tion excavated at its base, and in front by two lateral facets for the insertion, anteriorly, of the two inter- articular cartilages; it is bordered belind by another fossa which receives the posterior insertion of the internal meniscus. The inferior extremity, flattened behind and before, exhibits an articular surface moulded on the pulley of the astragalus, and two lateral tuberosities. The articular surface is formed by two deep cavities oblique from behind to before and within outwards, and separated by a median tenon which terminates pos- teriorly by a very prominent projection on which the bone rests when it is made to stand vertically on a horizontal plane. The external tuberosity) projects but little, and is traversed in its middle by a vertical fissure. The internal tuberosity,’ better defined, is margined posteriorly by an oblique channel. ‘Structure and development.—The tibia is very ‘compact in its inferior portion, and is developed from four chief centres of ossification. The body is formed’ by one and the superior extremity by two, the anterior tuberosity taking one of these; the last develops the whole of the inferior extremity. It is rare to see the external tuberosity of this extremity formed from a separate nucleus. 2. Fibula (or Peroneus). A small, undeveloped bone, elongated and sty- loid in shape, situated outside the tibia, and extend- ing from the superior extremity of that bone to the ‘middle or lower third of its body. ‘The middle portion of the fibula is thin and cylin- Fig. 64, POSTERIOR VIEW OF RIGHT TIBIA, 1, Tibial spine; 2, Fossa for the insertion of the internal meniscus; 3, External tuberosity with articulation for the fib- ula; 4, Fossa for the insertion of external meniscus; 5, Fibula, forming with the tibia the tibial arch; 6, Shaft, or body. of the tibia; 7, 8, External and in- ternal malleoli, inferior tuberosities, or lateral processes of the tibia; 9, Articular trochlex with a median ridge, for articulation with the astragalus, drical, and forms above, in common with the external border of the larger 1 The external malleolus of Man. 10 2 The internal malleolus. 102 THE BONES. bone, the tibial arch. Its superior extremity, wide and flattened on both sides, has received the name of head; it offers, on its internal face, a diarthrodial facet to articulate with the external and superior tuberosity of the tibia; on its external face it shows ligamentous imprints. The. inferior eatremity of the fibula terminates in a blunt point, and gives attachment to the ligamentous fibres that unite it to the tibia. The fibula is sometimes continued to the external inferior tuberosity of the latter bone, with which it is confounded; and as it is particularly under such circumstances that this tuberosity has been noticed to be deve- loped from a special nucleus, it seems quite natural, having regard to the disposition observed in pachyderms and carnivores, to consider it as the inferior extremity of the fibula joined to the tibia. With these animals, indeed, the tuberosity or external malleolus is formed by the inferior ex- tremity of the fibula. Structure and development—This bone is very compact, and developed from a single nucleus of ossification. 3. Patella. A small, short, and very compact bone, situated in front of the femoral trochlea, and annexed to the tibia, to which it is attached by three extremely solid ligamentous bands. The small polyhedron which it represents only offers for observation three faces: the superior, roughened, and serving for the insertion of the triceps cruralis and rectus muscles; the anterior, convex and irregular ; and the third, the posterior, moulded on the femoral trochlea, to which it is but imperfectly adapted. In the fresh state, however, the articular surfaco formed by the latter face is completed by a fibro-cartilaginous apparatus, which will be noticed when describing the femoro-tibial articulation. This articular surface is composed: 1, Of a median ridge, which occupies the bottom of the trochlear cavity ; 2, Of two depressed, gliding, lateral facets on the sides of this cavity; the internal facet is always larger than the external, a disposition which permits the patella of one limb to be distin- guished from that of the other. POSTERIOR FOOT. This region, which bears the greatest resemblance to the same region in the anterior limb, comprises three subdivisions: the tarsus, metatarsus, and the digital region. 1. Bones of the Tarsus. These are short, very compact bones, six or seven in number, and situated between the inferior extremity of the tibia and the superior extremity of the metatarsal bones; they are arranged, like the bones of the carpus, in two tiers—a superior and an inferior. The superior row only comprises two bones, the largest; these are the astragalus and the calcaneus (or calcis). The inferior row is formed, out- wardly, by the cuboides alone; inwardly and anteriorly, it is subdivided int» two secondary rows, the superior of which is constituted by the scaphoides, and the inferior by the large and small cuneiform bones. The last is sometimes divided into two, in which case there are three cuneiforms ; then the total number of the bones is seven. Astragalus—An irregular cubical bone, situated in front of the THE POSTERIOR LIMBS. 103 calcaneus, between the tibia and the seaphoid, and divided into five faces :-— Fig. 65, LEFT HIND FOOT; EXTERNAL ASPECT. 1, Tibia; 2, Summit of calcis or cal- caneus; 3, Astragalus; 4, Cuboid ; 5, Scaphoid; 6, Cuneiform mag- num; 7, Large metatarsal bone, 8, Small metatarsal bone; 9, Suf- fraginis, proximal, or first phalanx ; 10, Sesamoid bones ; 11, Coronary, middle phalanx; 12, second, or Pedal ” bone, or third or distal phalanx; 14, Navicular bone; 15, Basilar process of pedal bone. 1, A superior and anterior, formed as an articular pulley to correspond to the in- ferior extremity of the tibia; this pulley, oblique from above downwards, forwards, and outwards, may be considered as the type of the most perfect trochlea in the organism; its groove receives the median tenon of the tibia, and its two ridges or lips fit into the lateral furrows of that bone. 2, An inferior face, occupied by a slightly convex articular surface responding to the - scaphoid ; this surface is notched outwardly by an excavation for ligamentous insertion. 3, A posterior face, irregular, cut into three or four diarthrodial facets adapted for similar facets on the calcaneus, and which are separated by a wide, rugged excavation. 4, An external face, covered with imprints. 5, An internal face, provided below with a small tubercle of insertion. Calcaneus. —A bone vertically elongated, flattened on both sides, and presenting iwo faces, two borders, and two extremities. The external face is smooth and nearly plane. The internal face is excavated into a gliding groove to form the tarsal arch, in which passes the tendon of the perforans. The anterior border is slightly concave. The posterior border is thicker, straight, and rugged. The superior extremity, slightly tuberous, constitutes the summit of the calcaneus, and is divided into three parts: a middle, which gives attachment to the tendon of the gastrocnemius; the other, the anterior, is a smooth surface on which this tendon rests when the foot is much flexed; the third, altogether posterior, also constitutes a gliding surface for the tendon of the perforatus. The inferior extremity, wide and voluminous, shows in front three or four articular facets which correspond to the astragalus, and are separated, like those of the last bone, by an irregular and slightly excavated surface of insertion. Below, it shows for articulation with the cuboid a fifth facet, continuous with one of the preceding. Development.—The calcaneus is deve- loped from two nuclei of ossification, one of which is for the summit. Cuboid bone.—This little bone, situated at the external side of the scaphoid and the 104 THE BONES. large cuneiform bone, between the calcaneus and two of the metatarsals, does not resemble a cube, but a parellelopiped elongated from before to oehind, It offers sia faces: a superior, an articular face, and in contact with the calcaneus ; an inferior, also articular, responding to the principal and external rudimentary metatarsal bones; an internal, furnished with three facets for contact with the scaphoid and great cuneiform, and crossed from before to behind by a fissure, which forms with these two bones a vascular canal ; an external, an anterior, and a posterior, covered with imprints. Scaphoid bone (the large cuneiform of Percivall).—Flattened above and below, it is described as having two faces and a circumference. The faces, both articular, are furrowed by a channel of insertion, and are distinguished as superior and inferior. The first is concave, and responds to the astra- galus; the second is convex and in contact with the two cuneiform bones. The circumference offers, outwardly, two small facets which are adapted to similar facets on the cuboid bone. For the remainder of its extent, it is covered with imprints. Great Cuneiform bone (the middle cuneiform of Percivall).—Flattened above and below, and triangular in shape, this bone is much smaller than the scaphoid, though resembling it in a striking manner. Its superior face is in contact with the latter bone, and its inferior face articulates with the middle and internal lateral metatarsal bones. Its eternal border is provided with one or two facets to correspond with the cuboid bone; and its internal border also offers one, which is in contact with another on the small cuneiform. Its anterior border is roughened throughout its extent. Fig. 66. Fig, 67. LEFT HOCK; FRONT VIEW. LEFT HOCK; INTERNAL ASPECT. 1, Apex of calcaneus; 2, Astragalus, inner 1, Apex of calcaneus; 2, Inner articular ridge; 3, Scaphoid; 4, Cuneiform mag- ridge of astragalus ; 3, Navicular, scaphoid num; 5, Cuboides. or cuneiform medium; 4, Cuneiform mag- num; 5, Cuboides; 6, Cuneiform parvum. Small Cuneiform bone.—Situated at the inner side of the tarsus, this bone, the smallest of any yet examined, is elongated from before to behind, flattened on both sides, and wedged in between the os scaphoides, the large cuneiform bone, and the large and internal small rudimentary metatarsal bones, with which it corresponds by four articular facets: a superior, two se and internal. When this bone is in two portions, there are then three cuneiforms, which may be distinguished, as in Man, by namin them first, second, and third. : oe z THE POSTERIOR LIMBS. 2. Bones of the Metatarsus. 105 These bones are three in number, a median and two lateral, and offer the greatest analogy to the metacarpal bones. This enables us to dispense with a general description of them, and to confine ourselves only to indicating the differential characters which distinguish them from the corresponding bones in the anterior limb. The principal, or median metatarsal bone, is longer than the same metacarpal, and its body, instead of being slightly compressed before and behind, is nearly a regular cylinder. It presents out- wardly a fissure which is directed at first obliquely backwards and downwards, and afterwards descends vertically along the lateral external metatarsal bone. The articular surface of the superior extremity is ex- cavated in its centre by a large fossa of insertion. The inferior extremity is at the same time wider and thicker than that of the metacarpus. Of the two rudimentary (digital) or lateral metatarsal bones, the external is always longest and thickest. The internal bears on the superior face of its head three articular facets, two of which respond to the small cuneiform, and the third to the large bone of that name. 3. Bones of the Digital Region. The digital region of the posterior closely resembles that of the anterior limb. The analogy in the con- formation of these bones is even pushed so far, that it becomes very difficult to distinguish them from one another. It is remarked, nevertheless: 1, That the first pha- Janx is not so long as in the anterior limb, and less wide and thick at its inferior extremity, but is, on the contrary, wider and thicker at its superior extremity ; 2, That the lateral diameter of the second phalanx is shorter; 8, That the third phalanx, less spread out towards its inferior border, has more the shape of a V, and that its inferior face is more concave; 4, That the sesamoids are less voluminous; 5, That the navicular bone is shorter and narrower. DIFFERENTIAL CHARACTERS OF THE POSTERIOR LIMB IN OTHER THAN SOLIPED ANIMALS. A. Pevvis.—It is remarked: 1, That in all the domesticated animals, with the exception of Solipeds, the direction of the coxz is nearly horizontal; 2, That in all, except Solipeds, the ilium tends to assume a vertical direction; 3, That in all the trans- verse diameter of the pelvis is relatively less extensive. In the Ox, Sheep, and Goat, the space between the two coxee is scarcely so great in front as behind; the ilium is not volumi- nous, and has only three processes on the superexternal iliac spine. There is no furrow on the lower face of the pubis, and its upper face, like that of the ischium, is very concave. POSTERIOR ASPECT OF LEFT METATARSUS. 1, Head of principal metatarsal bone; 2, 3, External and in- ternal splint bones, or metatarsals of the rudimentary digits, 4, Rough surface for insertion of suspen- sory ligament; 5, Nutrient foramen; 6, Middle ridge of inferior articular surface. Three eminences are seen on the postero-external angle of the ischium, In early life, the ischio-pubic symphysis shows an epiphysary nucleus in the middle of its inferior face. (The epiphysis on the inner border of the ischium has been considered by some anatomists as an inde- pendent bone, ‘and deacribed by them as the interischial bone.) 106 THE BONES. The rim of the cotyloid cavity has also three notches, and the supracotyloid crest, or ischiatic spine, is very elevated and sharp, and but little roughened outwardly. The external iliac fossa of the Sheep and Goat is separated into two portions by a small longitudinal crest. : The pelvis of the Pég closely resembles that of the smaller ruminants; though the crest of the ilium is convex, and there is no protuberance outside the ischio-pubic symphysis. Ar : . In Carnivora the lateral diameter of the pelvis is greater behind than in front. The ilium is nearly vertical, and its external face is much depressed. The notch forming the ischial arch occupies no more than the internal moiety of the posterior border of the ischium ; between this arch and the ischiatic tuberosity is a rugged lip directed down- wards. There is no furrow on the lower face of the pubis. B. Tsicu.—In ail the domesticated animals except Solipeds, the femur tends to become curved, prismatic, and triangular ; the posterior face contracts, and the surfaces of insertion that it presents gradually approach each other until they become confounded and form the linea aspera in certain species. The head is more distinct; the small trochanter is a rough tubercle, and is joined to the large trochanter by an oblique osseous lip; the latter trochanter subsides and forms a single mass whose summit and convexity are con- founded; the third trochanter, the fossa, and the supracondyloid crest are more or less effaced. In the Oz, there is no subtrochanterian crest; the supracondyloid fossa is shallow, and the crest little noticeable. ‘The head is well detached and has its centre ex- cavated by a shallow fossa of insertion. The trochlea is narrow, and its inner border ascends much higher on the anterior face of the bone than the external. In the Sheep and Goat, the general fotm of the femur resembles that of the Ox. It is observed, however, that the body is slightly curved backwards; that the supracondyloid fossa is nearly obliterated; that the trochanter has subsided nearly to a level with the articular head, and that the trochlea is circumscribed by two equal-sized lips. In the femur of the Pig there is also noticed u supracondyloid fossa, but it is wide and shallow; the rugosities of the posterior face are replaced by some salient lines; the trochanter is on a level with the head; the latter is supported by a somewhat constricted neck, and is situated within and in front of the great trochanter. This latter disposition changes the direction of the great axis of the superior extremity, which obliquely crosses that of the inferior extremity. In the Dog and Cat, the femur is long and curved like a bow. The rugged surfaces of the posterior face are confounded, and form two crests representing the linea aspera of the human femur. These crests do not lie against each other in the middle portion of the bone; they are merely parallel, then they diverge above and below, to terminate beneath the great and small trochanters, and above the two condyles, The great tro- chanter is not so high as the articular head. The femur of Carnivora is also distin- guished: 1, By the complete absence of the third trochanter and the supracondyloid fossa—this last being replaced by a small tubercle which terminates below the external branch of the linea aspera; 2, By the marked constriction and length of the neck sup- porting the articular head; 3, By the depth of the digital fossa, which is bordered by an oblique lip extending from the great to the small trochanter. C. Lxc.—In the leg-bone there is observed, in the various domesticated animals, differ- ences analogous to those mentioned as existing in the fore-arm of the thoracic limb. More particularly is this the case with regard to the development of the fibula; in Ruminants this bone is reduced to its inferior nucleus. In these animals the patella is also very narrow; and in all the domesticated species except Solipeds, the articular grooves in the lower end of the tibia are directed immediately from before to behind. In the Oz, the tibia is short; it is longer in the Goat and the Sheep. The tibia of these animals is remarkable for: 1, The absence of the lateral facet on the supero- external tuberosity; 2, The absence of a vertical fossa on the anterior tuberosity ; 8, The absence of roughened lines on the posterior face; the obliquity downwards and inwards of the inferior articular surface. The most salient point of this surface is the anterior extremity of the middle tenon. The body of the fibula and its upper extremity are replaced by a fibrous cord which is sometimes ossified wholly or in part. In the Pig, the fibula is flattened on both sides, extends the whole length of the leg, and is united to the tibia by its two extremities: above, by a diarthrodial facet: below, by an interosseous ligament. It is developed from three ossifie centres: the inferior articulates with the calcaneus and astragalus, and forms a prominence resembling the external malleolus. In Carnivora, the tibia is long and slender, and presents a salient anterior crest, The THE POSTERIOR LIMBS. 107 fibula is also as long as the tibia, and is united to that bone at three points: at the two extremities by articular surfaces, in the inferior third and middle by an interosseous ligament. _ D. Posrertor Foor.—l. Bones of the tarsus—The number of tarsal bones varies a little in the domesticated animals, as the following list will show : Carnivora and Pig. gts Ox, Sheep, and Goat . e 8 © | 2 In the Dog, Cat, and Pig, there are three cuneiform bones, and in the Ox and Sheep, in addition to there being only two cuneiforms, the scaphoid and cuboid bones are con- solidated into one piece. The astragalus of the carnivora articulates with the scaphoid by means of a veritable head, separated from the rest of the bone by a constriction termed the ncck of the astia- galus. The cuboid and the cuneiform bones respond to all the metatarsals. In the Pig, the astragalus and calcaneus are very long. The cuneiforms and cuboid respond to the four perfect digits. The tarsus of the domesticated Ruminants isslender above. The astragalus is elongated from above to below, and is united to the scaphoid by an antero-posterior groove, and to the calcaneus by a more superficial vertical groove. The calcaneus is long and tlin; the posterior gliding surface on the summit is excavated into a channel; the small cuneiform is pisiform and but slizhtly developed. 2. Bones of the metatarsus—The metatarsus is also a region in which the number of bones varies in the domesticated animals. Thus in the Carnivora and Pig there are five. and only two in Ruminants. The metatarsals of the Carnivora and Pig are exactly like the same bones in the anterior limb, Those of Ruminants are slightly different. In the Dog and Cat are one rudimentary and four perfect metatarsals. The former is articulated with the internal cuneiform, and represents the vestige of the thumb, The Pig has four perfect metatarsals, and an internal rudimentary one. The latter is a small bone flattened on both sides, articulating by means of a diarthrodial facet, and sometimes consolidated behind the upper end of the fourth metatarsal. In the Ox, Sheep, and Goat, is found a principal and a rudimentary metatarsal bone. The latter is like the rudimentary metacarpal bone, but the former differs from the principal metacarpal bone in being longer, quadrilateral in form, and having a vascular canal traversing the posterior face of its upper extremity. 3. Bones of the digital region.—In all the domesticated animals, the posterior digits comport themselves exactly like the anterior. The Carnivora alone offer a notable differ- ence; in them, in reality, the thumb does not exist, or rather, it is only represented by the rudimentary metatarsal bone alluded to above. Nevertheless, it frequently occurs that a completely developed thumb is found in this animal; and in this case the rudi- mentary metatarsal is ordinarily followed by a ligamentous cord, to which is suspend d a bony stylet that represents either the inferior extremity of the metatarsal, or the first phalanx; it is to this stylet that are found articulated in succession the second and third halanges. P CP entoast Fuchs, of Carlsruhe, found, in a Newfoundland dog, four true claws and two false; the internal of the latter corresponded to a well-developed, small metatarsal bone, while the external was only rudimentary, terminating in a point, and bound to the tarsus by a simple ligament.) COMPARISON OF THE ABDOMINAL LIMB OF MAN WITH THAT OF ANIMALS, A. Petvis.—The longitudinal axis of the pelvis of Man forms, with the horizon, an angle of about 40°. ; ‘The bones which compose it are proportionately larger and stronger t!.an in all the domesticated animals. The two faces of the ilium, and especially the inner face, are much hollowed; the iliac crest has the form of an italic S. ; The pubis alone participates in the formation of the pelvic symphysis, and the con- cavity which, in the domesticated animals, is called the ischial arch, is designated in Man the pubic arch. : : as ; ; In consequence of the excavation on the inner face of the ilium, the pelvic cavity may be divided into the great and lesser pelvis In the latter are lodged the genital and urinary organs, as well as the extremity cof the digestive tube. ; 8. Tuigu.—The femur of Man is nearly vertical, and situated in a direction slightly 108 THE BONES. oblique downwards and inwards; it presents a curvature forwards. The body of the bone is prismatic and triangular in its middle part ; the posterior border of this prism forms a somewhat salient crest, which takes the place of all the insertion eminences on the pos- terior aspect of the femur in animals, and is designated the linea aspera. This line bifureates above and below; below, the branches margin a triangular or popliteal space. Fig. 69. HUMAN PELVIS; FEMALE. 1, Last lumbar vertebra; 2, 2, Intervertebral substance; 3, Promontory of the sacrum; 4, Anterior surface of the sacrum; 5, Coccyx; 6, Iliac fosse; 7, Antero- superior spinous process; 8, Antero-inferior spinous process; 9, Acetabulum.— a. Its notch; b, Body of ischium; ¢, Its tuberosity; d, Its spine; e, Pubis; f, Symphysis pubis; g, Arch of the pubes; h, Angle of os pubis; 2, Spine of pubes, with crest between it and h; h, &, Pectineal line; /, Z, Ilio-pectineal line, with its prolongation, m, m; m, Ilio-pectineal eminence; 0, Smooth surface for femoral vessels; p, p, Great sacro-ischiatic notch. The head is supported by a long neck, inserted obliquely into the superior extremity. The two coudyles are joined together in front by the trochlea, which is wide and shallow. C. Lec.—Three bones: the tibia, fibula, and patella. The tibia is very long; its crest (or spinous process) is much more developed than in any of the domesticated animals, and describes a kind of curve like an italic S. On the inner aspect of the inferior extremity is seen a voluminous process which occupies, inwardly, a portion of the tibio tarsal articulation: this is the internal malleolus, The articular surface is not exactly formed to correspond with the whole articular surface of the astragalus. The fibula is a3 long as the tibia. It is prismatic, and slightly twisted on itself. It articulates above and below with the tibia. ‘lhe lower extremity responds to the astra- galus, and forms a prominence named the external malleolus, There is nothing particular to note in the patella. D. Foor.—The foot of Man is situated in a horizontal direction. Its upper aspect is convex; its inferior face is excavated, and it rests on the ground by its two extremities, 1. Tarsus.—In the tursus there are seven bones, three of which are cuneiform The astragalus articulates with the tibia and fibula; it responds to the scaphoid by a well detached convex articnlar surface, named the head. In the bones of the lower row, it is remarked that the cuboid responds to the fifth and fourth metatarsals: the first cuneiform to the third; the second cunciform to the second metatarsal, and the third to the first. 2. Metatarsus——The metatarsus is composed of five bony columns, nearly parallel to each other. They are enumerated from without to within, and increase in leneth from the first to the fourth; tle fifth is the shortest and most voluminous. = THE LIMBS IN GENERAL. ‘3. Digital region.—This comprises five digits or toes. are analogous to those of the fingers, from which they are size, 109 ie phalanges of these toes They inerease in volume from the first to the fifth digit, Eee een RIGHT HUMAN FEMUR} ANTERIOR ASPECT. 1, Shaft; 2, Head; 3, Neck; 4, Great tro- chanter; 5, Anterior intertrochanteric lines 6, Lesser trochanter ; 7, External condyle ; 8, In- ternal condyle; 9, Tu- berosity for attachment of external lateral liga ment; 10, Fossa for ten- don of origin of popliteus muscle; 11, Tuberosity for attachment of in- ternal lateral ligament. HUMAN TIBIA AND FIB- ULA OF RIGHT LEG; ANTERIOR ASPECT. 1, Shaft of tibia; 2, Inner tuberosity; 3, Outer tuberosity; 4, Spinous process; 5, Tubercle; 6, Internal surface of shaft; 7, Lower extremity of tibia; 8, Internal mal- leolus; 9, Shaft of fib- ula; 10, Its upper ex- tremity; 11, Its lower extremity; between 1 and 6 is the sharp crest of the tibia. DORSAL SURFACE OF LEFT HUMAN FOOT, 1, Astragalus; 2, Its An- terior extremity articu- lating with the cuboid bone, 4; 3, 3, Calcis; 4, Scaphoid; 5, Inter- nal cuneiform bone; 6, Middle cuneiform bone; 7, External cuneiform bone; 8, Cuboid bone; 9, Metatarsal bones of first and second toes; 10, First phalanx of great toe; 11, Second ditto; 12, 15, 14, Pha- langes of second tae. Articte VI.—Tue Limes 1n GENERAL AND THEIR PARALLELISM. A. Tue Lmss my Gunnrat.—The interrupted columns which compose the limbs are destined not only to support the trunk in a stationary attitude, but also to transport it during progression. This double destination gives rise toa difference between the anterior and posterior members, The front limbs, 110 THE BONES. being nearer the centre of gravity than those behind, have to sustain the largest share of the weight. They ought, consequently, to be specially organised as organs of support. Therefore it is that the four principal rays composing each of them—shoulder, arm, fore-arm, and foot—although flexed, or disposed to be flexed, in an inverse sense to one another, oppose to the pressure of the weight of the trunk, which tends incessantly to throw them down, obstacles purely mechanical, and of such energy that we may still understand how the body can be sustained on the anterior limbs, if we suppose all the muscular masses surrounding these bony rays removed except one. Thus, the weight of the body is at first transmitted to the scapula through the muscles thut attach that bone to the trunk. It then passes to the humerus, and from thence to the radius, to be thrown, finally, on the different pieces composing the foot. Now the humerus forming with the scapula an angle which is open behind, and with the bones of the fore-arm another angle open in front, the weight of the body pressing continually on these angles tends to close them, and thus cause the flexion of the bony rays. But this result is prevented by the combined action of two muscular powers—the biceps and the extensors of the fore-arm. With regard to the radius, carpus, and metacarpus, owing to their verticul direction they themselves support the pressure of the weight of the body without requiring any muscular aid. But the digital region, being directed obliquely forward and downward, forms, with the principal metacarpal, a third angle open in front, for the sustenance of which nature has given solid, inert, or contractile mechanical bands. The anterior limbs are also agents of transport, for they can elevate the trunk by the spring of their bony rays, and fix themselves on the ground by their free extremity. The posterior limbs are less favourably disposed than those in front to assume the function of columns of support, as their rays are for the most part in a state of permanent flexion, and joined in an angular manner to one another, as may be seen by glancing at the skeleton (See Figs. 1, 2, 8, 4, 5). It is therefore necessary that muscular agency should prevent the breaking-down of these rays. Though defective as supporting columns, they are nevertheless admirably designed to serve as agents of locomotion. The slightest erection of these inclined rays propels the mass of the body forward, and this impulsion is almost wholly transmitted to the trunk in consequence of the very intimate union of the pelvis with the vertebral column. B. ParaubEL BETWEEN THE ANTERIOR AND Posterior Liwss.—After what has just been said, it will be seen that the anterior limbs are more par- ticularly destined for the support of the body, while.the posterior ones more especially play the part of impulsive agents in the locomotory acts. Notwithstanding this difference in the functions assigned them, these two columns offer in their conformation such striking resemblances to each other, that some authors have been inclined to consider the posterior as an exact repetition of the anterior limb. The following is a brief analysis of the analogies existing between them. At the end of the last century, Winslow and Vicq-d’Azyr, and nearer our own time, Cuvier, Flourens, Paul Gervais, Martins, Gegenbaur, and Lavocat, have occupied themselves with the parallelism existing between the anterior and the posterior members. All these anatomists did not absolutely arrive at the same conclusion ; for several of them, forgetting that the question should be examined in the whole animal series, made Man alone the subject of their THE LIMBS IN GENERAL. 111 meditations. In such a matter, it must not be forgotten that the limbs are constructed with a view to their physiological functions, and that the differences remarked in examining them in several species are dictated by the kind of life the animals are intended to lead. ‘ Vicq-d’Azyr and Cuvier recommend that the anterior and posterior limbs of opposite sides should be compared. Martins and Gegenbaur, allowing a torsion of the humerus of 180°, advise that the two members of the same side should be collated, care being taken to make allowance for the untwisting of the 180° contortion at the lower end of the humerus. Lastly, Flourens and Lavocat contrast the two members of the same pair with each other, after placing the hand in a position of natural pronation by rotation of the radius on the ulna, and without turning either limb or ray, or even a portion of a ray, no matter what kind of animal may be under examination. We will adopt the latter proceeding, as it is the simplest and most natural. Parallel between the cora and scapula.—The analogies existing between these two bones are but little striking at first sight ; nevertheless, with atten- tion there is no difficulty in finding in the coxa the three pieces that enter into the composition of the shoulder. The ilium represents the scapula. The external iliac fossa reminds one of the supra- and subspinous fossee. Occasionally, there is met with in the Horse a rudiment of the crest dividing the iliac fossa into two parts, and, in some animals—the Pig, Sheep, and Goat—this crest, which is the trace of the scapular spine, becomes constant and very evident. With regard to the cotyloid cavity, it repeats in the posterior limb the glenoid cavity of the scapula. There remains to determine in the latter bone the portions analogous to the ischium and pubis. If we rely upon the evidence afforded by the muscular insertions, we come to the conclusion that the ischium corresponds to the coracoid process, and the pubis to the clavicle of animals which are provided with one. It will also be remarked that the coxa is directed backwards, while the scapula inclines obliquely forwards; this opposition in the direction of the bones in no way alters their analogies ; the functions of the members to which they correspond require this inverse position. Parallel between the femur and humerus—-The resemblance between these two bones is remarkable. Thus there is found in the first: 1, An articular head, better detached than that of the humerus, but shaped in the game manner; 2, A trochanter analogous to the great tuberosity, and also like it decomposable into three distinct parts—summit, crest, and convexity ; 3, A lesser trochanter, representing the smaller tuberosity ; 4, An eminence for the insertion of the superficial gluteus muscle, which takes the place of the deltoid imprint; 5, An inferior articular pulley continued between the two condyles by a non-articular groove; this trochlea certainly corresponds to the median groove of the inferior humeral face. There are, no doubt, differences between the two bones, but they have no bearing upon the result just indicated. Thus the linea aspera of the femur is situated behind; that of the humerus in front. In the femur the two condyles of the inferior extremity are placed behind the trochlea ; the contrary holds in the humerus. These modifications are necessary in order to give the movements of the limbs a convenient direction. The leg is flexed backward on the thigh, while the fore-arm is flexed in front on the humerus. : Parallel between the bones of the leg and those of the fore-arm.—tt 1s 112 THE BONES. more particularly in these two regions that the question of analogies has been resolved in a contradictory manner by anatomists. It would have appeared less complicated had it been studied in a large number of species, It has been pretended that the patella and the upper part of the tibia represent the superior extremity of the ulna and radius; and that the inferior portion of the ulna is represented by the fibula, and the lower part of the radius by that of the tibia. This opinion is erroneous. It is true that in Man the tibia and patella articulate with the femur, as the superior extremity of the ulna and radius responds to the humerus. But in quad- rupeds, whose thoracic members are destined to sustain the weight of the body, this disposition is no longer observed; the radius is seen to give support to all the humeral surface, just as the tibia receives the femoral surface; and, besides, the ulna becomes only a simple complement to the elbow articulation, as the fibula does to the femoro-tibial articulation. The tibia, therefore, corresponds to the radius, and the fibula to the ulna. The olecranon is represented by the superior nucleus of the fibula, and not by the patella. The latter bone is nothing more than a kind of sesamoid, intended to facilitate the action of the extensor muscles of the leg. It might be objected to this comparigon that, in the anterior limb, the extensor muscles are attached to the olecranon. But we reply that it matters little where the muscles which move the leg or arm are fixed on one or other of the two bones of these regions, because these bones act conjointly in the movements of flexion and extension. Parallel between the bones of the posterior and those of the anterior foot.— The analogy becomes so marked when these two regions are compared, that it is scarcely necessary to allude to it. The tarsal bones are to the posterior limb what the carpals are to the anterior one; it is even possible to compare, one by one, the several pieces in these regions. The metatarsals are but a repetition of the metacarpals; while the digital bones are so much alike that it is difficult to distinguish the anterior from the posterior phalanges. CHAPTER III. THE BONES IN BIRDS. Tuxse animals, destined for the most part to sustain themselves in the air, should exhibit in the conformation of their skeleton all the conditions which may favour zrial locomotion ; from this arise the differences which distinguish their skeleton from that of mammalia,—differences which will now be rapidly traced. Verteprat, CoLumn.— Cervical vertebrx.—The cervical stalk represents in the bird, as in the mammal, a kind of balancing pole curved like an 8, which supports the head, and by its changes of furm and direction varies the centre of gravity. When a bird rises in the air and flies rapidly, it lengthens the neck and stretches out the head to carry the centre of gravity forwards. But when it rests on the ground, it makes the balancing-pole assume the natural and more or less graceful inflection, by throwing the head backwards, and transferring the greater portion of the weight of its body to the columns of support formed by the posterior members. These displacements of the centre of gravity are executed in birds on a more extensive scale than in mammalia; the vertebral stalk in the former is also longer, lighter, and enjoys an excessive mobility. The vertebrae composing it number fourteen in fouls, twelve in the pigeon, fifteen in the duck, and eighteen in the goose; in the swan twenty-three have been counted :—a curious variety which singularly contrasts with the numerical unity noticed as one of the most remarkable characters in mammalia! These vertebra: are generally longer than in the latter class, and are particularly distinguished by the configuration of the THE BONES IN BIRDS. 113 articular surfaces of the inferior part or bod iarthrodi c y. These are diarthyodial facets convex i ove sense and concave in the other, articulating the vertebral bodies by a alitable acd Fig. 73. o B. “ia SKELETON OF A FOWL. Spinous process of the third vertebra ; 2, Inferior lord prolongation of the transverse process of From Ato B, Cervical Vertebre.—1, ridge on body of the same ; 3, Sty 114 THE BONES. reciprocal clamping. In this manner, the anterior head of the body of each vertebra ig replaced by a facet concave from one side to the other, and convex vertically ; while the posterior extremity of the bone bears, instead of a concavity, a facet convex in the lateral sense, and concave from above to below. The inferior crest of the body (fig. 73, 2, 2’) only exists in the first and last vertebre; but it forms a veritable spine. analogous to that observed in the lumbar vertebre of the rabbit. The spinous process (fig. 73, 1, 1’) only forms a simple crest in the middle part of the neck, it becomes more salient in the vertebres which occupy the two extremities of this region. The transverse process represents on the side of the vertebra a thick, obtuse, and irregular tubercle, situated under the anterior articular process, and pierced at its base by a large vertebral foramen (tig. 73, 4, 4°). It is most frequently furnished with a small styloid prolongation (fiz, 73, 3, 3’) directed backwards and downwards, forming an epiphysis at an early period, and representing a real undeveloped rib. The atlas has no transverse processes, This vertebra is shaped like a thin ring, and is excavated on its anterior contour by a small cavity into which is received the single condyle of the occipital bone. The axis shows a very marked odontoid process with a single facet under that eminence. Dorsal vertebra (Fig. 73. 8B, C.).—These are seven in the Fowl and Pigeon, and nine in the Goose and Duck, they are nearly always consolidated intoa single piece to which the trunk is fixed, and which gives the wings a solid support in the violent efforts that flight demands. The two or three last are often even covered by the wing-bones, and joined to them. The inferior crest of the body forms a very long spine, especially in the first vertebre. The spinous processes, flat, wide, short, and consolidated with each other by their opposite borders, constitute a long crest extending from the last cervical vertebra to the bones of the wings (fig. 73, 7). Tne transverse processes widen to their summit; in the fowl they are nearly constantly fused with each other. Lumbar and sacral vertebre.—All these vertebrae are formed exactly on the same type; so that it becomes difficult, if not impossible, to fix the point where the lumbar region ends or the sacral begins. At first independent of each other, these vertebra, numbering fourteen, soon become consolidated with one another and with the ribs; but their primitive separation is always indicated by the lateral septa which form, on their inferior face, the vestiges of the transverse processes. The former are closely united to the latter in the dorsal region. Coccygeal vertebra.—In the coccygeal region, the spine recovers its mobility. The tail of the bird, indeed, fulfils the office of a rudder to direct it during flight; and it is absolutely necessary that the vertebree which serve as a base fur the steering feathers should preserve their independence, so as to allow these to be carried to the right, left, downwards, or upwards. ‘These vertebre, seven in number, present spinous processes which are often bifurcated, transverse processes very developed, and sometimes even spines more or less long on the inferior surface of their bodies. The last vertebra is always the most voluminous; it is flattened on both sides, and terminates in a curved-up point. Heap (Fig. 73, F. G.).—The head of the bird is small, and of a conical form. The anterior extremity is elongated, and terminated by a pointed or flattened beak, which allows the animal to cut the air with more favility. ; - x the same; 4, Vertebral foramen of the same; 1’, 2', 3’, 4’, The same parts in the twelfth vertebra——From B to c, Dorsal Vertebra.—6, Spinous process of the first ; 7, Crest formed by the union of the other spinous processes.—From D to E. Cocey- geal Vertebra.—r, G, Head.—8, Interorbital septum; 9, Foramen of communica- tion between the two orbits; 10, Premaxillary bone; 10’, External openings of the nose; 11, Maxilla; 12, Square bone; 13, Jugal bone.—u, Sternum.—14, Brisket or keel; 15, Episternal process; 16, Internal lateral process; 17, Lateral external process ; 18, Membrane which closes the internal notch; 19 Membrane of the external notch.—1z, etc., Superior ribs.—20, Posterior process of the fifth.—J, Inferior ribs; K, Scapula; L, Coracoid bone; m, Furculum.—m, m, Its two branches.—Nn, Humerus; 0, Ulna—o, Radius.—p, p’, Bones of carpus Q, Q', Bones of metacarpus; R, First phalanx of the large digit of the wing.—r, Second phalanx of the same.—r’, Phalanx of thumb; s, Ilium; s’, Ischium: s” Pubis.—21, Sciatic foramen; 22, Foramen ovale.—r, Femur} u, Patella; v, Tibia; x, Fibula—y, Single bone of tarsus.—Y, Metatarsus,—23, Superior process" ‘representing a united metatarsal bone; 24, Process supporting the claw.— Z, etc., Digits. : THE BONES IN BIRDS. 115 Bones of the cranium—tThe bones which compose the cranium are, as in mammalia, an occipital, parietal, frontal, ethmoid, sphenoid, and two temporals. These bones aro net isolated from each other, excepting during early life in the shell; and the ossifying process which unites them is so rapid, that the cranium, shortly after hatching, is already a single piece. No detailed description of the separate bones will be given here, but only a few brief observations which may be of some utility. Thus, the occipital bone shows for articulation with the spine only a single condyle, situated under the occipital foramen, and excavated by a slight groove. In palmipedes, this bone is pierced, behind the crests which give attachment to the extensor muscles, by two foramina which penctrate the cranium, and represent permanent fontanella. The parietal bone is feebly developed, and formed from only two primary nuclei. The frontal is the largest bone of the cranium; its orbital process is supported by a particular piece which is generally considered as belonging to the large wing of the sphenoid. The perpendicular lamina of the ethmoid is considerable, and forms between the two orbits a thin vertical septum (fig. 73, 8). Its posterior border is notched opposite to the optic foramen, and thus constitutes an opening which com- municates between the two orbital cavities (fig. 73, 9). It is also channeled, near its upper border, by a fissure which terminates by two openings at its extremities, one entering the cranium, the other the nasal cavities. ‘This fissure and these foramina permit the passage of the ethmoidal nerve, which in this way traverses the orbit before arriving at its destination. The ethmoddal cells are more membranous than bony ; their base is attached to a very delicate transverse plite, which is often membranous and not eribbled, and forms part of the «anterior orbital wall. These cells replace, at the same time, the lateral masses of the ethmoid and turbinated bones of mammalia. The sphenoid appears to be formed of a single piece, and shows on its sides two diarthrodial facets corresponding to the pteryguids. It is pierced by one foramen for the passage of the optic nerves; but this foramen opens on the outer and opposite side of the posterior notch of the interorbital septum, and thus allows each of the nerves passing through it to reach the eye for which it was intended. i. ; : ae It is worthy of remark, that an analogous disposition is also noticed in the rabbit. The temporal bones present at their base an articular surface corresponding to the square bone. In the fowl species, the zygomatic process forms a small flattened tongue, directed forwards, sometimes free, and at other times united by its superior border to the summit of the orbital process. These two eminences are exceedingly short in pigeons. In palmipedes they are consolidated and confounded so intimately, that it becomes impossible to distinguish them from one another. From this union results a long and strong process, which inclines forward and meets a purticular prolongation of the os unguis, forming with it areal bony arch. This arch limits, below and outwardly, the orbital cavity. : . Bones of the face—The supermaxilla ec mprises: a premaxilla, two nasal, two lachrymal, two palate, two pterygoid, two zygomatic bones, and a vomer. The inferior jaw has for its base a maxillary bone, which articulates with the cranium by means = two supplementary pieces named the square bones. The premaxillary bone is ee before hatching is completed, of two lateral pieces, which represent the two gos premaxillaries of mammals. This bone is very considerable, and of itself forms the base of the upper beak, whose form it determines; it is pointed and conical in the ga and wide and flattened above and below in palmipedes. In front it cireumscribes the external openings of the nose, and is prolonged superiorly into two lengthy pecs which dovetail between the nasal bones. Two inferior processes belonging also to ze bone concur in the formation of the palatine roof. The supermazillaries, Paes a the supermaxillaries of mammals, are two rudimentary bones situated on the a si - at the base of the beak. They form a part of the palatine roof and the wa ae i nasal cavities. The nasal bones circumscribe above, inwardly, and even et ar yp i external orifices of these cavities. The palate bones encircle, as in ee e on ura openings of the nose, and constitute in great part the roof of the palate a eir pee tremity lies against the pterygoids; the anterior joins the supermaxillaries an inf er praeen of the premaxillary bone. The pterygofds extend obliquely from the eohenriast the square bones, and are united to the sphenoid by diarthrouial articulation. 1 i 1 is really striking, and might, in our opinion, serve a8 a basis for pena of ai interorbital septam. We are tempted, indeed, to consider flije We lamina as the inferior sphenoid and the middle portion of the ethmoid of birds. This a ee of viewing it tends to confirm the ideas of M. Tabourin on the inferior sphenoid and the ethmoid of mammals, 116 THE BONES. The zygomatic bones have the form of two very thin stylets, and are united to the square bone by their posterior, and consolidated with the supermaxillary by their anterior extremity. The vomer separates the guttural openings of the nose from one another. The bones of the upper jaw are not fused with each other so rapidly as the bones of the cranium. The ascending processes of the premaxillary and nasal bones even remain for a long time united to the frontal bone by a simple synarthrodial articulation. This arrangement allows the upper beak to execute a certain elevating movement, of which we will speak when describing the articulations. . The inferior maxillary bone is originally formed of a great number of distinct seg- ments which are soon united into a solid piece. The square, petrous, or bone of the tympanum ought to be considered as detached from the temporal. It is prismatic in shape, and provided on its upper surface with a diarthrodial facet which unites it to the temporal, and on its lower face with another facet articulating with the branch of the maxilla. Outwards it joins the zygomatic bone, and inwards with the pterygoid: Behind, it gives attachment to the membrane of the tympanum; and in front it presents a small eminence of insertion which Meckel considered « second zygomatic TOCess. : Tuorax.—Sternum (fig. 73, H).—The sternum of birds, serving as a basis of support to the muscles moving the wings, should offer, and does in fact show, a remarkable degree of strength, because of the extraordinary volume of these muscles. And these being more powerful and energetic as the bird exhibits a greater degree of aptitude for flight, it results that the structure of the sternum is solid.in proportion as the bird is strong on the wing, For this reason we may infallibly pronounce as to the extent and power of a bird’s flight by an inspection of the sternum of individuals of its species. In this respect, however, we only announce what is well known to be a particular application of the rules established by the great law of concordance between the anatomical disposition of organs and their ~ physiological finality. Studied in Palmipedes, which will serve as a type for description, the sternum presents itself in the form of a large rectangular cuirass, elongate from before to behind, of itself constituting the inferior wall of the thoracic cavity, and also largely protecting the abdominal cavity. Its superior face is concave, while the inferior is convex, and entirely occupied by the insertion of the pectoral muscles. It presents, on the median line, a thin and very salient ridge, named the brisket (or keel), which in a remarkable manner multipiies the points of attachment of these muscles. The anterior border offers in its middle a small eminence of insertion, the episternal. Laterally, two articular grooves are seen which correspond to the coracoids. The posterior border is eut by two notches which are often converted into foramina. On the lateral borders are observed small double articular facets answering to the inferior ribs. The angles which separate these two borders from the anterior are both prolonged into a little eminence, named by some authors the costal process, In the Fowl, the sternum is not so strong as in the Goose or Duck. On each side of the brisket it shows two wide notches, which greatly reduce its substance. These notches, closed in the fresh state by membranes, are distinguished as external and internal. The latter, of greater size than the former, extends nearly to the extremity of the bone. From this division of the lateral plates of the sternum result two long and slender processes directel backwards. The external terminates by becoming widened, and forming a kind of bony plate, which covers the last inferior ribs. The sternum of Pigeons is distinguished by the enormous development of the brisket. The two notches of the fowl are also met with in these birds, but the internal is nearly always converted into a narrow foramen. This comparative study of the sternum in the chief domesticated birds leads us to appreciate the correctness of the principles just enunciated, wit! regard to the form and extent this bone may exhibit. The Gall/naceous Birds, properly so called, which fly little and badly, have the sternum singularly weakened by the deep notches cut in its lateral parts. With Palmipedes, the sternum is wide and but slightly notched, so that the goose and duck, which waddle along so awkwardly in our poultry yards, are capable of sustaining long and rapid flight, like that of the wild individuals of the same species. With regard to Pigeons, which are well known to be swift and powerful flyers, may this aloes i not be due to the extraordinary development of the keel which constitutes the risket ? Ritbs.—In the Fowl and Pigeon there are seven pairs of ribs; and in the Duck nine pairs. Articulated superiorly with the dorsal vertebra, as in mammals, these bones are provided near their middle with a flat eminence which commences at the posterior border, and is directed backwards and upwards to rest by its free extremity on the external face of the next rib, These eminences (Fig. 73, 20) form an epiphysis at an gh J THE BONES IN BIRDS. early period, and aro usually absent in the first and last ri i efficacious manner to increase the solidity of the thorax. Pe ENSY eo ta ae 7 or ribs by a diarthrodial articulation (Fig. 73,1. These ung, and all terminate at their lower extremity by a double 1 , : ; they are nearly alwa absent in the two first ribs. It is not rare to see the last united to the one before it, instead of passing directly tu the sternum; in which case i i i er ae Pee case it comports itself like the ANTERIOR MemBers.—Shoulder-bone-—The shoulder ticular bone named the coracoid by Cuvier; and a clavi with that of the opposite side, a single bone called The scapula is narrow, elongated, and falciform, anterior extremity only forms a portion of the gleno a fibro-cartilage with the fork of the coravoid bone. represents the coracoid process of mammals, and obliquely from above downwards, and before to behind. Its superior extremity is often fused with the scapula, and united at an acute angle with that bone to form a portion of the articular cavity which receives the head of the humerus. Its inferior extremity is flattened from before to behind, and responds by a diarthrodial articulation to the anterior border of the sternum. The coracoid is long in birds which fly slowly ; it is, on the contrary, short, thick, and therefore very solid in quick flyers. The fork is a single bone, shaped like a V or U, situated at the base of the two wings, in front of the trunk, and in an oblique direction downwards and backwards. The two branches which form it represent the clavicles; they meet and are united at their inferior extremities, where they describe a curvilinear angle more or less open, attached to the brisket by means of a membranous ligament. Their superior extremity rests within, and opposite to the glenoid cavity, against the scapula aud coracoid, forming with these bones a remarkable foramen, through which passes the tendon of the elevator muscle of the wing (Fig. 73, A, 4, B,6). The fork plays the part of an elastic spring, whose office it is to prevent the wings coming towards each other during cpntraction of the depressor muscles. The conformation of this bone is, therefore, like the sternum, related to the extent and power of flight ; and for this reason it is that, in swift flyers, the two branches of the furculum are thick, solid, widely separated, and curved like a U; while in those which fly heavily and with difficulty, these branches are thin and weak, and joined at an acute angle. The latter formation greatly diminishes its strength, and lessens, in a singular manner, the reactionary power of the bony arch it represents. Bone of the arm.—The humerus offers an articular oval-shaped head, and an air- opening placed beneath this eminence. It is long in Palmipedes, ordinarily so in the Gallinace proper, and very short in Pigeons. Bones of the fore-arm.—The radius is much less voluminous than the ulna. The latter has an extremely short olecranon; and the two bones are separated from one another in their middle part to meet again at their extremities, where they are united by ligamentous bands in such a way as to render the movements of pronation and supination impossible. This mode of fastening, which nevertheless does not prevent the two bones from gliding slightly on each other in the direction of their length, has been wisely adopted by nature in order that the wing might strike the air, like an oar, by its inferior face ; otherwise, the resistance of the aerial medium would make these two bones pivot, and cause the wing to present itself to the air in a wrong direction. Bones of the carpus.—These are only two, and are distinguished by the names of radius and ulna, in consequence of their corresponding more particularly to these bones in other animals. . Bones of the metacarpus.—These also number only two, and are separated at their middle portion, to be consolidated at their extremities. aA Bones of the digital region.—The wing of a bird is composed of three digits. One of them, which resembles the thumb and forms the basis of the false wing, is composed of a single styloid-shaped phalanx, articulated at the base of a small particular process belonging to the superior extremity of the largest metacarpal bone. The largest digit comprises two phalanges which succeed the last bone. The third digit is represented by a small rudimentary phalanx, which corresponds to the inferior extremity of the small metacarpal bone, and lies beside the first phalanx of the large digit in the closest manner. It is well to remark that the hand and tie fore-arm are longer in proportion to the qnality of flight ; those two regions of the wing, for example, are very short in Gallinaceous rds. : Fae = De Mempers.—Coca or os iliac.—This is a voluminous and very solid piece, 11 comprises: a scapula, a par- cle, which forms, in coalescing the fork ( furculum), or os furculare, and shows no trace of a spine. Its id cavity, and is united by means of The latter is so named because it is a long prismatic bone, directed 118 THE BONES. particularly in walking birds, and composed, as in the mammalia, of an ilium, ischium, and pubis, The ilium is consolidated with the last dorsal, the lumbar, and the sacral vertebree; it is excavated on its internal face. The ¢schium partly incloses the side of the pelvic cavity ; between its internal border and the external border of the ilium is an orifice which replaces the great ischiatic notch, Its inferior border is united to the pubis. The latter is thin and elongated, and follows the direction of the inferior border of the ischium, with it circumscribing an oval opening more or less spacious. Its inferior extremity extends beyond the ischium to curve inwards towards that of the opposite side, but without uniting with it. We do not, therefore, find the pelvic symphysis in birds, and the pelvis is widely open below, a circumstance which favours the passage of the egg through the cavity and out of the cloaca. The cotyloid cavity is perforated by an opening at the bottom which traverses the bone. Thigh bone.—The femur is articulated inferiorly with the patella, tibia, and fibula. In all walking birds, like the gallinace, it is long and strong, as well as the rays below it. Leg bones.—The patella is wide aud thin. The tibia terminates, below, by two con- dyles separated by a groove which becomes articular behind. The fibula articulates by its head with the external condyle of the femur, and is consolidated with the tibia; it never descends to the inferior extremity of that bone. Tarsal bones.—The tarsus appears to be altogether absent in birds. Nevertheless we may venture to consider, as a vestige of the bones of this region, a small bony nucleus buried in a fibro-cartilaginous mass which glides on the posterior pulley of the tibia. This nucleus represents the calcaneus of mammals. Metatarsal bone —A single metatarsal bone is found in birds, articulating superiorly with the inferior extremity of the tibia, and terminating inferiorly by three pulleys which support the three principal digits. This bone shows in the Fowl, near its inferior third, a conical process turned backwards, which serves as a base for the spur. Behind its superior extremity, it exhibits another which may be considered as a consolidated metatarsal bone. Bones of the digital region.—All the domesticated birds have four digits on the inferior members: three principal, directed forwards, and one rudimentary, carried backwards. The first, designated as internal, median, and external, articulate with the inferior pulleys of the metatarsal bones. The internal is formed by three phalanges, the second has four, and the third five. These phalanges are formed something like those of t: e carnivora: the last is pointed, conical, and enveloped in a horny sheath. The fowh digit, or thumb, is composed of three pieces; one of these, the first, is generally con- sidered as a rudimentary metatarsal bone. It is attached by fibro-cartilaginous tissue a the inner and posterior aspect of the inferior extremity of the principal metatarsal one, CHAPTER IV. THEORY OF THE VERTEBRAL CONSTITUTION OF THE SKELETON. In the series of vertebrated animals the bony pieces of the trunk bearing the name of vertebre are those which offer the highest degree of fixity, and to which the existence or the arrangement of the others appears to be subor- dinate. This feature in organisation, recognised by E. Geoffroy Saint- ‘Hilaire and Professor Owen, has caused these.men of science to assert that the type of construction of vertebrated animals is the vertebra. After E. Geoffroy Saint-Hilaire and Professor Owen, several German, English, and French anatomists have studied the vertebral composition of the skeleton ; and among the works published in France on this subject must be specially noticed those of M. Lavocat.! In principle, all the writers have arrived at the same conclusions, and only differ in some few details. It is certain that the base of the vertebral column is formed by a series of bony segments. Each of these segments is called an osteodesm, and each . osteodesm represents the body or centrum of a vertebra. (The distinguished anatomist and Director of the Imperial Veterinary School of . Toulouse.) THE VERTEBRAL CONSTITUTION OF THE SKELETON. 119 In examining the dorsal region, it is evident that to the body or centrum of a vertebra are added two complete osseous arches, a superior and an inferior. The superior arch is formed by the vertebral lamina; the inferior by the ribs, the cartilages, and a portion of the sternum. The first is desig- nated the neural arch, because it furnishes a protecting sheath for the nervous centres; and the second, which more particularly protects the vascular system, is called the hemal arch (see Fig. 10). The hemal arch may have prolongations or appendices more or less developed, and comparable to the apophysary prolongations of the ribs in birds and some fishes. Such is the general composition of a typical vertebra; but there are a to be distinguished in the neural and hemal arches the following parts :— NEURAL ARCH. HEMAL ARCH, 1. Neural parapophysis =the posterior - Hemal parapophysis = the tuberosity costal cupola. of the rib, 2. Neural metapophysis = the anterior . Hemal metapophysis = the head of the costal cupola. rib. 3. Neural diapophysis = the summit of the . Heemal diapophysis = the rib proper. transverse process. . Heumapophysis = the costal cartilage. 4, Neurapophysis = the vertebral lamina. . Hemal spine = the corresponding 5. Neural spine =the summit of the sternal portion. spinous process, OUP oo nw land The vertebrae sometimes depart more or less from the model just described. They may vary not only from one species to another, but also in the same animal, and even in the same region. Thus the neural arch may be absent, as has been observed in certain coccygeal vertebre ; or the hemal arch is incomplete or null, as in the cervical or lumbar vertebre ; or, lastly, the arches are often unequal; though this inequality is of no import- ance, since their size is in relation to the volume of the parts they should rotect. - Notwitstanding these differences and variations, or the transformations experienced by certain parts, there is not a bone in the skeleton which can- not be included in the vertebral type. The vertebra being admitted as the type of construction of the skeleton, it is easy to find it in all the regions of the bony framework. In the thoraco-abdominal region, the centrum, neural arch, and hemal arch are readily perceived ; in the lumbar vertebre, the enormously developed trans- verse process indicates the existence of an infravertebral arch. In the sacral region, the bony girdle of the pelvis represents the hemal arch. The posterior limbs, articulating with the bones of the pelvis, belong to the hemal arch, and should be considered as appendices of this arch, analogous to the costal appendices of birds. ; ae The cervical region may be compared to the sacral region; as in it the inferior hemal arch is represented by the osseous ring supporting the anterior imbs—the scapulo-clavicular cincture. The limbs themselves are appendices of the cervical hemal arch. oy Difficulties begin to appear when the extremities of the trunk—the head | and coceyx—come to be examined. Nevertheless, the composition of the coccyx is revealed when the caudal vertebre of certain fishes, especially those of the pleuronectide, in which the neural and hemal arches are com plete, are examined. But the vertebral constitution of the head remained for long time an insoluble question, or was solved in a contradictory 120 THE BONES. manner by the naturalists who attempted it. Some admitted a single cephalic vertebra; others admitted three or four ; while others again arrived at six or seven. : _ These difficulties and contradictory results may be understood, when it is 2, Parieto-maxillary vertebra; 3, Fronto-mandibular vertebra ; 4, Naso-turbinal vertebra. CEPHALIC VERTEBR& OF THE DOG.—After Lavocat. 1, Occipito-hyoideal vertebra ; borne in mind what profound modifications the vertebra must have ex- perienced to constitute the bones of the head At present the problem appears solved. The head is composed of four vertebre, in which are found the various parts enumerated in the description, of the typical vertebra. THE VERTEBRAL CONSTITUTION OF THE SKELETON, 121 In the four classes of vertebrata, the head is constantly formed of four vertebrae, which are determined as follows :”! | VERTEBRA, CENTRUM. | NEURAL ARCH, : HASMAL ARCH. \ : ! Occipito-hyoidel. Basilar process | Occipital (3 pieces). | Hyoideal appa- , of the Occipi- | Mastoid walls of the | 1atus (5 pieces). tal. » ‘Tympanum. H Sao | Parieto-maxillary. | Body of the pos- | Wing and _ pterygoid | Inferior Maxilla i i terior Sphe- | process of the pos | 5 pieves), 3 noid. {terior Sphenoid. | | Squamous portion and ‘ zyyomatic process of | | the Temporal. { Parietal. ! i Fronto-mandibular, , Body of the | Wing and_ pterygoid | Jugal. Auterior Sphe- | process of the anterior | Lavhrymal, noid. | Sphenoid. ‘ Palatine. | Posterior Frontal and , Supermaxillary. its orbitul process. ; Premaxillary. ' Frontal. | | Naso-turbinal. Vomer, Ethmoid. | Turbinated Nasal. | Subetumoidal, I The number of cephalic vertebre is invariable, as each is destined to. lodge the organs of one of the four senses. The occipito-hyoideal lodges the principal organs of hearing; the paricto-maxillary osteodesm protects the sense of taste; finally, the organs of vision are sustained by the fronto-man- dibular vertebra, while the naso-turbinal contains the sense of smell. It was therefore with reason that Geoffroy Saiut-Hilaire and Professor Owen proclaimed that the type of construction of the vertebrated animals is the vertebra. SECOND SECTION. Tue ARTICULATIONS. CHAPTER I. THE ARTICULATIONS IN GENERAL. Tux different pieces constituting the solid framework of the animal body are, as has been said, united in such a manner that they can move one upon the other From this union results the articulations or articular joints, whose construction will now be referred to in a general manner, before commencing a particular description of each. To form articulations, the bones correspond to each other by certain points of their periphery, which are named articular surfaces. Every articu- 1 Lavocat, ‘ Nouvelles études sur le systeme vertébral,’ 1860, 122 THE ARTICULATIONS. lation is, therefore, essentially constituted by two opposite osseous surfaces, which are moulded to each other. These are either contiguous, independent, and very movable—continuous with each other by means of a cartilaginous substance which condemns them, if not to total immobility, at least to very Fig. 75. A | —~2 PLANS OF THE DIFFERENT GLASSES OF ARTICULATIONS. A, Suture.—1, Periosteum; 2, Sutural ligament.—b, Amphiarthrosis; a, First degree.—l1, Periosteum; 2, Articular cartilage; 3, Interarticular ligament.—d, Second degree; 4, Single cavity in the interarticular ligament.—c, Third degree ; 5, Double cavity in the interarticular ligament.—c, Diarthrosis; 6, Simple diartinrosis—1, Periosteum; 2, Articular cartilage; 3, Epithelial layer of the synovial membrane—dotted line; 4, Fibrous capsule; 5, Cul-de-sac of the syno- vial membrane ; 6, Fibrous layer of the synovial membrane.—e, Double diarthrosis ; 7, Interarticular meniscus; 8, 9, Cavities of the two synovial membranes. limited movements : or united by a fibro-cartilage whose elasticity permits a certain degree of displacement between the bones which are in contact. In the first case, the articulations are classed as diarthroses, or movable articulations. In the second, they are designated synarthroses, sutures, or immovable articulations. THE ARTICULATIONS IN GENERAL, 123 In the third, they are amphiarthroses, or mixed articulations; so termed because they participate in the movements of the other two classes ; synar- throses, by the continuity established between the articular surfaces; and diarthroses, by the extensive motion they permit. The general characters that distinguish each of these three great classes of articulations will be successively studied. (The study of the articulations, or rather of the ligaments, is termed syndesmology—from ovv, together, and decpds, bond; or arthrology—from &pOpov, a joint, and Adyos, a description. ) GENERAL CHARACTERS OF DIARTHROSES. We ought to consider in the diarthrodial articulations: 1, The con- tiguous bony surfaces which form them ; 2, The cartilaginous layer (cartilages of incrustation) which cover these; 3, The fibro-cartilaginous tissue (articular jibro-cartilages) which complete them, when they are not shaped so as to be reciprocally adapted to each other; 4, The kgaments which maintain them in contact; 5, The serous membranes (synovial capsules) that cover the internal face of the latter, and which secrete the synovia, a kind of animal oil that facilitates the gliding of the articular surfaces; 6, The movements of which these articulations may be the seat; 7, Their methodical classifica- tion; 8, Their nomenclature. ARTICULAR SurFaces.—These surfaces have the common character of being destitute of asperities, so that they can glide with the greatest facility on each other. They are designated, according to their form, by the names of facets, heads, condyles, cotyles, glenes, pulleys, etc. There is no need to revert to their general description, as they have already been sufiiciently studied in the osteology; so we will confine ourselves to repeating that they are found at the extremities of long bones, on the faces of short bones, and on the angles of wide bones." We may mention also that they are often excavated by one or several hollows named synovial fosse, a sort of natural reservoirs which receive the unctuous fluid secreted by the interarticular serous membranes. Carntitaces or Incrustation.—This designation is given to the layers of cartilaginous matter which, as it were, varnish the articular surfaces they adhere to by their inner face; their free surface is distinguished by a remarkable polish and brilliancy Thicker towards the centre than at the circumference when they cover bony eminences, these cartilages show an inverse disposition when they line cavities. They are elastic, of a pearly whiteness, and resisting, though they are soft enough to be cut by a sharp instrument; in a word, they possess all the physical characteristics of the primary cartilage of bones They appear to be formed of parallel fibres placed perpendicnlar to the bony surfaces, and implanted it. these by one of their extremities ; the opposite extremity corresponding to the free surface of the cartilage. Viewed by the microscope. they are found to consist of a fundamental substance excavated by small cavities The cartilage of incrustation therefore belongs to the group of true or hyaline cartilages. The fundamental matter is amorphous and homogeneous, and more or -less transparent, according to its thickness. It is transformed into chondrine by boiling in water. The cavities are irregular, and more or less wide. They contain from one to five cells whose walls are very thin, and their contents slightly gran- ular; in the centre of each cell is a nucleus with a nucleolus. These 124 cavities are elongated and directed articular surface in the deep layer ; THE ARTICULATIONS. almost perpendicularly towards the in the middle layer they are oblique, and are parallel to the surface of friction in the superficial layer. SECTION OF BRANCIIIAL CARTILAGE OF TADPOLE. u, Group of four cells separating from each other; 0, Pair of cells in apposition ; ¢, c, Nuclei of cartilage-cells; d, Cavity con- taining three cells. These cells are im- bedded in the finely-granular matrix, or fundamental substance, (Under a high magnifying power the fundamental substance, or matrix, loses its homogeneous and amorphous character, and appears to be granular or faintly striated. In the midst of this granular matrix, the lacune or cavities are observed to contain from one to six different-sized cells. It has been stated that a membrane lines these spaces. In addition to the granular matter observed in the cells, it is not rare to find fat globules, The nuclei of the cells vary from soba 10 s2yq of an inch in diameter. The cells multiply endogenously.) The cartilage cells are insoluble in boiling water; consequently, so far as their chemical composition is con- cerned, they are distinct from the fundamental substance. The diarthrodial cartilages receive neither vessels nor nerves. The presence of cartilages of incrustation in the articulations is of the greatest importance. When they are worn, absorbed, or transformed into bone in consequence of certain articular maladies, the movements become painful and very difficult. With regard to the part they play in the economy, it may be said that: 1, They favour, by their smoothness, the gliding ard displace- ment of the bones, 2, They attenuate, by their suppleness and elasticity, the violent shocks to which the articulations are exposed; 3, They resist the’ wear and deformation of the articular surfaces. CompLemuntary Fisro-cantinaces.—There are several kinds of com- plementary fibro-cartilages :—Some (interosseous) represent circular cushions which bolster the margins of certain cavities, filling up the notches which might render them imperfect. They increase the depth of these cavities Fig. 77. FIBRO-CARTILAGE, MAGNIFIED 155 TimEs. Showing interlacement of fibrous fasciculi, with scattered groups of cartilage-cells, and protect their borders from injury. Others (interarticular) are inter- posed between articular surfaces when these do not exactly fit each other, as THE ARTICULATIONS IN GENERAL 125 when two opposing extremities are convex. It may be remembered that the lateral tuberosities of each tibial surface present, for articulation with the condyles of the femur, two convex diarthrodial faces whose coaptation is rendered perfect by the interposition between each condyle and correspond: ing tibial surface of a crescent-shaped fibro-cartilage, which for this reason has been named a meniscus. In other joints these interarticular fibro- cartilages are shaped like discs or biconcave lenses. There then result double diarthroses :—example, the temporo-maxillary articulation. (Fibro- cartilage also covers bony surfaces over which tendons play, as on the trochlear surface of the humerus, postero-inferior face of the navicular bone, and elsewhere. In these situations it is named stratyform Jibro-cartilage.) These organs are formed, as their name indicates, by fibrous and car- tilaginous tissue; their mode of association need not be referred to here, though it may be observed that the cartilage is more particularly found in all those points where there is most articular friction. They receive vessels, and sometimes nerves, Licaments.—These are bands which unite contiguous diarthrodial surfaces. They are sometimes formed of white fibrous tissue, and some- times of yellow; from whence their division into two great classes of white and yellow ligaments. a. The white ligaments are distinguished by the pearly whiteness of their tissue and want of elasticity. Those which are found on the outer Fig 78 Fig 79. if vt Y Le \ ik NE aN (AINA a LN 7 MAR WHITE OR NON-ELASTIC FIBROUS YELLOW OR ELASTIC FIBROUS TISSUE, FROM TISSUE. THE LIGAMENTUM NUCH. } Ah \) ) oi) Coy oe i aspect of the articulations are termed peripheral, and those in their interior are designated interosseous or interarticular ligaments. The peripheral ligaments are generally composed of parallel fibres collected in fasciculi, or spread out as membranes. In the first they are called funicular, or ribbon-shaped; in the second, they are termed mem- braniform, or capsular. The funicular ligaments constitute short, round, or flattened bands, attached by their extremities to the two bones they unite; they are lined on their inner aspect by the synovial capsule, and covered externally by tendons, aponeuroses, muscles, vessels, or nerves. The capsular ligaments are often complete—that is to say, they envelope the whole articulation like a sack. At other times they are incomplete, and 126 THE ARTICULATIONS. then they are simple membranes, binding together the different funicular bands of a joint. . The interosseous ligaments, less numerous than the preceding, are often formed of interlacing fibres; they are always funicular, and fixed by their extremities into excavations in the centre of articular surfaces. b. The yellow ligaments are all peripheral, funicular, or membranous, and enjoy a marked degree of elasticity, which permits them mechanically to bring back to their usual position the bony levers which have been momen- tarily displaced. These ligaments, which are powerful auxiliaries to the muscular forces, are destined to give equilibrium in a permanent manner to the weight of certain parts of the body which incessantly tend to fall to the round. ‘ SynovraL CapsuLes.—These are very thin membranes of a serous nature, intended to secrete the synovia. They are composed of two layers: a deep, formed by fasciculi of the connective tissue; the other, superficial, is of an epithelial character. The first sometimes adheres intimately to the inner face of the funicular or membranous ligaments of the articulation ; at other times it is loosely attached to them by an abundance of connective tissue. The second layer is constituted by a single row of flattened polygonal cells. It is generally admitted that the synovial membranes comport themselves like the other serous membranes, by forming sacs which are everywhere closed. According to this admission, a synovial membrane, after covering the internal face of the peripheral ligaments of a diarthrodial articulation, ought to be prolonged on the free surface of the cartilages of incrustation, and should give them their brilliancy and polish, But it is necessary to state that this is a pure hypothesis, against which rises a multitude of care: fully-observed facts. The discussion of these belongs to general anatomy, but they will be referred to here as briefly as possible. 1. If direct observation be consulted, it gives on this debated subject the most precise information; the cartilages are uncovered, and there is no synovial membrane on their face. The anatomists who have mistaken for this membrane the thin pellicle which it is possible to render evident on the cartilages in obliquely cutting their substance and separating morsels by tearing it off, were evidently deceived. This pellicle has nothing of a serous nature in its texture; it is not vascular, for it has never been possible to inject vessels on the surface of cartilages, nor yet in their thickness; it is not covered by epithelium; and submitted to microscopical examination, it exhibits all the characters of the amorphous matter of cartilage. It ought, then, to be considered as a cartilaginous pellicle, detached from the super- ficial layers of the articular surface—a pellicle which it has always been impossible to find on cartilages which are quite fresh; and it has never been possible to observe it without giving, by a preliminary desiccation, a certain degree of tenacity to the cartilaginous substance about to. be examined. 2. Pathological facts prove nothing in favour of the existence of a synovial membrane on the cartilages. Hypertrophy of this pretended membrane has never been witnessed ; the fungosities looked upon asa result of this hypertrophy are derived from another source. It has been demonstrated that they extend, in certain cases, from the articular margins of the cartila- ginous surface, whence their successive invasions may often be followed. In other cases, the vegetating membrane which constitutes them appears in the centre of the articular surfaces, at points deprived of cartilage ; they after- wards extend to a certain distance on the remaining cartilage. THE ARTICULATIONS IN GENERAL, 127 3. It may be asked of the partisans of the opinion now combated, how they can believe in the existence of a serous membrane between two articular surfaces, without its being exposed to bruises and destruction a thousand times in the day? Do they take into account the amount of pressure sustained by certain articulations, and the intense friction to which their surfaces are submitted? Have they compared the intensity of these destructive influences, with the delicate texture of the serous membranes, and their great inflammatory susceptibility ? It is sufficient to lightly touch in this way the weak side of our adversaries’ argument, and to conclude the third portion of this discussion: There is friction between the cartilages of the two opposed articular surfaces, therefore there must be wear, this is a physical law which no body escapes, let it be as hard as the diamond, or as soft as caoutchouc. And if there is wear between these rubbing surfaces, there cannot be an irritable and sensitive membrane lying on the inert and insensible strata which constitute them. In fine, a synovial membrane, after being fixed to the margin of the articular cartilage of a diarthrodial joint, is reflected in every direction to cover the inner aspect of the liga- ments, and becomes attached to the periphery of the diarthrodial surface corresponding to the first. There are generally found within articulations little masses of fat which push the synovial membrane enveloping them inwards. Erroneously con- sidered by Clopton Havers as glands for the secretion of synovia, these accumulations of fat have been named synovial fringes. They are more par- ticularly numerous in the neighbourhood of the articular margins: that is, on the edges of diarthrodial surfaces. The synovia is a viscid, colourless, or slightly yellow fluid, in its physical characters somewhat resembling oil; it does not possess them, however, so far as its composition is concerned, for chemical analysis has not demonstrated the presence of fatty principles. It is the albumen it contains which gives it its viscidity, and which fits it for lubricating the articular surfaces over which it is spread. Its use in the animal economy is absolutely identical with that of the greasy substances employed to lubricate the axles of carriages. : Movenents.—The movements peculiar to diarthrodial articulations are divided into seven principal classes : 1. Simple gliding, the only movement possible between two plane or undulating facets. 2. Fleaion, which brings two bony pieces nearer each other by closing more or less their angle of union. 3. Extension, the inverse movement, during which the bones are straightened on each other. 4, Adduction, which brings the inferior extremity of the movable bone towards the median line. 5. Abduction, the contrary movement to the preceding 6. Circumduction, or the sling movement, during which the bone passes successively through the last four positions. 7. Rotation, in which one bone pivots on another CragsrricaTIon or THE DiarrHroses.—The basis of this classification is founded on the configuration of the articular surfaces and_the nature of the movements they permit. This double base serves to establish five kinds of diarthrodial articulation - eget 1, Enarthrosis, characterised by the reception of an articular head within 128 THE ARTICULATIONS. a cavity of appropriate form. This articulation may be the seat of the most extensive and varied movements: flexion, extension, abduction, adduction, circumduction, and rotation. Example: the coxo-femoral articulation. 2. The trochlean, angular ginglymoid, or perfect hinge articulation, when the articular surfaces are formed into trochlea, reciprocally fitting into each other, and whose movements—flexion and extension only—are executed with the precision of a hinge. Example: the tibio-tarsal ar- ticulation. : 3. The condyloid, or imperfect hinge articulation, which permits, like the preceding, the two principal movements of extension and flexion, and the accessory movements of rotation or lateral inclination. The articular surfaces, fhough very diversely shaped, nevertheless exhibit in all the articulations one or more condyles opposed to an equal number of oval excavations. Example: the femoro-tibial articulation. 4, The pivot, trochoid, or lateral ginglymoid articulation, is a diarthrosis formed by a pivot which turns in a senti-cylindrical cavity. Rotation is the only movement. Example: the atlo-axoid articulation. 5. Arthrodia, or planiform diarthrosis, is constituted by plane, or nearly plane facets. Gliding is the only possible movement. Example: the carpo- metacarpal articulation. Nomznciature.—The names of the articulations are usually those of the bones which form them. For instance, the scapulo-humeral articulation is the joint between the scapula and humerus ; the intervertebral articulations join to each other the various pieces constituting the spine. When the qualifying name of an articulation is composed of two elements, as in the first instance, it is well to place first the word which indicates the bone usually most fixed. GENERAL CHARACTERS OF THE SYNARTHROSES. Sutures are the temporary articulations which exist only at an early period of life. They nearly all disappear in the adult animal, in con- sequence of the.bones forming them becoming consolidated. They belong almost exclusively to the bones of the head. ArricuLar Surraces.—The bones forming these come in contact by their borders or angles, which, for this purpose, generally present very anfractuous surfaces. Sometimes they are cut perpendicularly and simply roughened; at other times they are bevelled and joined by means of fine lamine or trifling inequalities; again, they are notched into deep and sinuous dentations; and lastly, one bone is fixed into a groove cut in the other. It will be understood that such conformations of the articular surfaces ought to limit their movements and assure the solidity of their union. Moves or Union.—Cartilage interposed between these synarthrodial surfaces directly unites them to each other. It absolutely possesses the same texture as the primary cartilage of the bones, and like it, has the property of becoming ossified after having been vascularised. This ossi- fication, which causes the disappearance of the sutures, occurs earlier inwards than outwards. The periosteum, in passing from one bone to another, adheres intimately to the sutural cartilage, and also aids in bringing about a more complete synarthroses. It should, therefore, be included in their means of union. Movements.—These are very obscure, and only noticeable in young ARTICULATIONS OF MAMMALIA IN PARTICULAR. 129 animals by the elasticity they communicate to the bony walls of the cranium or face. In the adult, they may be said to be null. Crassirication.—There are four principal descriptions of sutures : _ 1. When two wide bones correspond by means of denticulations fitting into each other, the suture is named frue or dentated. Example: the articulations uniting the three portions of the parietal bone. 2. If the opposed borders of two bones in contact are widely bevelled, one inwards, the other outwards, it forms a scaly or squamous suture. Example: the parieto-temporal articulations, 3. When the union of bones takes place by plane or roughened surfaces, evt perpendicularly on their borders or angles, this constitutes the harmonia suture, or suture by juxtaposition (or appo- sition). Example: the occipito-temporal articulations. 4. The schindylesis, or mortised suture, results from the reception of a bony plate into a groove more or less deep in another bone. Example: the spheno-frontal and supermaxillo-nasal articulations. GENERAL CHARACTERS OF THE AMPHIARTHROSES OR SYMPHYSES,. ArticuLar Surraces.—They are frequently smooth, and formed almost on the same model as the diarthrodial surfaces. They are covered by a thin layer of cartilage, but instead of being smooth and polished, they are more or less rugged, without, however, presenting the anfractuous disposition of the majority of synarthrodial surfaces. Moves or Unton.—The organs which perform this office are: 1, The fibro-cartilage which establishes continuity between the articular surfaces ; 2, Ribbon-shaped or peripheral ligaments. These latter do not differ from the analogous bands attaching the diarthrodial articulations. With regard to the fibro-cartilage, it is distinguished from the complementary discs of these same articulations by a less intimate mixture of the cartilaginous and fibrous elements entering into its composition. The last may be sometimes absent, as well asthe peripheral bands; and then the articulation only differs from the synarthroses by the extent of motion it permits Occasionally the interarticular fibro-cartilages are excavated by one or two little narrow cavities ; but these are never lined by a synovial membrane like the diarthrodial cavities, Movements.--The amphiarthroses only permit of a see-saw or swinging movement. the extent of which depends on the thickness of the intermediate fibro-cartilage. Cuasstrication.—Only one kind of amphiarthrosis is recognised, the most remarkable example of which is found in the articulations between the bodies of the vertebra. CHAPTER II. ARTICULATIONS OF MAMMALIA IN PARTICULAR. In the special study of the articulations, the same order will be followed as for the bones; the articulations of the spine will be first noticed, then those of the head, thorax, and anterior and posterior limbs. ; Preparation —The preparation of the bones which have been described has not been made the subject of any particular recommendation, because it suffices, in order to study them, to remove the soft parts by which they 130 THE ARTICULATIONS. are surrounded either by boiling, maceration, or scraping. But when we come to examine the soft textures, in order to do so profitably it is necessary to learn beforehand the rules which should be followed in their preparation, The following are laid down with regard to the study of the articulations : 1. To prepare the articulations, young subjects are chosen in preference to those ad- vanced in years, because the density of the cellular tissue in them is not so great, and this tissue is easily removed from around the ligaments. As these are prepared with difficulty when the external surface is in a dry state, care should be taken before dissecting them to have them excluded from the air by covering them with damp cloths, or with the skin of the animal. . ; 2. It is convenient to separate the articulation we wish to dissect by sawing through the bones at a certain distance from the articular surfaces. ‘The manipulation of the part is then rendered easier, and its dissection can be made under the most favourable conditions. 3. It is necessary to preserve as carefully as possible the muscles surrounding the articulations, in order to be able to study their relations with the ligaments which bind these. If it be absolutely necessary to remove them, their insertions corresponding to the articulation should always be retained. 4, The capsular ligaments should be the first studied, as these have soon to be removed the better to show the funicular ligaments. These, in their turn, must be sacrificed in order to display, by different sections, the interosseous cords, when these exist. Lastly, the two articular surfaces should be completely separated, so as to examine their conformation. 5. The synovial membranes, with their different culs-de-sac, being a very important study, with reference to the diagnosis and treatment of articular tumours, it is convenient to devote a special piece to the examination of these serous membranes. It is very useful to inject their interior with plaster or tallow coloured black, in order to distend their cavities, and thus aid the study of their relations with ligaments, tendons, or muscles. For the preparation of each articulation it is not necessary to give any directions; a glance at the figures accompanying the description will suffice to dispel any embarass- ment the student may experience, while he always requires particular indications. (Notwithstanding the above remarks with regard to the preparation of the ligaments, I have thought it advisable to follow the example given in the last edition of ‘Leyh’s Anatomy’ by Zundel, and briefly indicate the readiest method of demonstrating these organs, for the special benefit of the student.) ArticLe J.—ARTICULATIONS OF THE SPINE. (Preparation.—Remove all the soft parts surrounding the vertebral column, taking care not to injure the inferior longitudinal ligament in cutting away the pillars of the diaphragra and the psoas muscles; nor the ligaments uniting the articular processes to each other and the transverse processes of the dorsal vertebrx to the ribs, in removing the supercostal and transverse spinal muscles. To expose the common superior longitudinal ligament, separate the bodies of the vertebre frum their annular portions by the saw or chisel, and remove the spinal cord and dura mater; in doing this the inferior face of the interannular ligaments will be also removed. Examine an intervertebral fibro-cartilage by two sections—a transverse at an equal distance from the two vertebra, and a longi- tudinal through the middle line of the bodies.) These articulations are intrinsic and extrinsic. The first comprises all the articulations of the vertebra with each other; the second those of the spine with the head, the ribs, and the coxa. Intervertebral Articulations. The vertebra correspond: 1, By their bodies; 2, By their spinal or annular portion. There results from this union two kinds of articulation, which must be studied separately, as they do not belong to the same class. It is well to mention, however, that the general details into which this study leads us apply only to the articulations uniting the last six ARTICULATIONS OF THE SPINE. 131 cervical vertebra, all the dorsal and lumbar vertebre, and the first sacral vertebra, ; Union or THE Vertzpr” By Tuer Bopres.—The articulations forming this union are so many amphiarthroses. Articular surfaces.—The vertebral bodies come into contact by the surfaces which terminate them before and behind. In the cervical region these surfaces represent, anteriorly, a veritable head, posteriorly, a cotyloid cavity which receives the head of the next vertcbra. Beginning from the first dorsal vertebra and passing on to the sacrum, these tend to become pac iia weir nee and more plane, though they still preserve their convexity and concavity. Modes of wnion.—1, By fibro-cartilages interposed between the articular surfaces; 2, By a common superior vertebral ligament; 3, By a common inferior vertebral ligament. a. Intervertebral fibro-cartilages (Fig. 80, 1, 1).—These are circular or elliptical discs, convex in front, concave behind, and solidly fixed by their faces to the articular planes which they separate. The fibro-cartilaginous substance composing them consists of concentric layers, which become denser and closer to each other as they near the circumference; they even disappear towards the centre of the disc, where this substance becomes pulpy and assumes the histological characters of pure cartilage. It may be remarked, that each of these layers is made up of a collection of thick parallel filaments, which cross with those of other layers like an X, and are attached by their extremities to the articular surfaces. From this arrangement results so inti- mate an adherence between the vertebral bodies and their intermediate fibro- cartilages, that an attempt to disunite them is more likely to determine a fracture of the former. The fibro-cartilages, thicker in the cervical and lumbar regions than in the dorsal, respond by their circumference to the two common ligaments. Those which separate the vertebre of the back concur to form the intervertebral cavities, » hich are destincd for the reception of the heads of the ribs, and give attachment to the interosseous costo- vertebral ligaments. (Leyh ieee the superficial fibres of the excentric layer of these fibro-cartilages as intervertebral ligaments. Luschka has shown that the ‘cartilages are in reality articular capsules.) 2 a b. Common superior vertebral ligament (Fig 838, 1).—This ligament extends from the axis to the sacrum, and is lodged in the spinal canal ; it represents a long fibrous band cut on its borders into wide festoons. (The wide portions correspond to the discs.) ; ; By its inferior face, it is attached to the intervertebral discs and the triangular imprints on the upper faces of the bodies of the vertebra. Its superior face is in contact with the dura mater through the medium of an abundant cellulo-adipose tissue. Its borders are margined by the intra- vertebral venous sinuses (venee basium vertebrarium). ; c. Common inferior vertebral ligament (Fig. 84, 5).—Situated under the spine, this ligament is absent in the cervical and the anterior third of thedorsal region. It only really begins about the sixth or eighth vertebra of the latter region, and is prolonged in the form of a cord, at first narrow, then gradually widening until it reaches the sacrum, on the inferior surface of which it terminates by @ decreasing expansion, From its commencement, it 18 attached to the inferior crest of the bodies of the vertebree and the interver- tebral discs. By its inferior face, it responds to the posterior aorta. (Leyh commences this ligament at the seventh cervical vertebra, and says 132 THE ARTICULATIONS. that it adheres to the crests on the bodies of the dorsal and lumbar vertebra, as well as to the lower face of the sacrum and coccyx. At the fifth dorsal vertebra it widens and thickens, and in the lumbar region is bound up with the pillars of the diaphragm and confounded on each side with the large ligaments of the pelvis.) Unron or THe Vertesra sy THEIR Sprvaz Porrions.—Each vertebra, in uniting by its annular portion with that which follows or precedes it, forms a double arthrodial joint. : ; Articular surfaces. —These are the facets cut on the anterior or posterior articular processes, and which have been described when speaking of tlie vertebre themselves. They are covered by a thin layer of cartilage. Modes of wnion.—1, A common superspinous ligament; 2, Interspinous ligaments; 3, Interlamellar ligaments ; 4, Ligamentous capsules, proper to the articular processes, ae a. Common superspinous ligament.—This ligament, whose name suf- ficiently indicates its situation, extends from the sacrum to the occipital bone and is divided into two portions : one posterior, or superspinous dorso-lumbar ligament; the other anterior, or superspinous cervical ligament. These two ligaments, although continuous with one another, yet differ so strikingly in form and structure that they are best described separately. 1. Superdorso-lumbar ligament (Fig. 80, 2).—This is a cord of white fibrous tissue, which commences behind on the sacral spine and ceases in front about the inferior third of the dorsal region by insensibly assuming the texture and elasticity of the cervical ligament, with which it is continuous, It is attached in its course to the summits of all the lumbar spinous processes and to the ten or twelve last dorsal. On the sacral spine, it is confounded with the superior ilio-sacral ligaments, In the lumbar region, it is united on each side to the aponeuroses of the common mass of muscles. 2. Superspinous cervical, or simply cervical ligament (Fig. 104, 1, 2).— This ligament is entirely formed of yellow fibrous tissue, and constitutes, in the median plane of the body, a very remarkable elastic apparatus which separates the superior cervical muscles of the right side from those of the left, and plays the part not entirely of an articular band, but rather of a permanent stay charged to balance the weight of the head. In the cervical ligament there is distinguished a funicular and a lameliar portion. The first, usually called the cord of the cervical ligament, is a wide funiculus which extends directly from the first dorsal spinous processes to the summit of the head. Divided into two lateral lips by a median groove, this cord is continued posteriorly with the dorso-lumbar ligament, and is inserted forwards into the cervical tuberosity of the occipital bone. It is covered above by a mass of fibro-adipose tissue which, in certain common- bred horses, is very abundant. Below, it gives rise, in its posterior two- thirds, to the majority of the fibres belonging to the lamellar portion. .On the sides, it receives the insertions of several cervical muscles. The lamellar portion, comprised between the funicular portion, the spinous processes of the second dorsal vertebra, and the cervical stalk, constitutes a vast triangular and vertical septum, which itself results from the apposition of the two lamine which lie back to back, and are united by cellular tissue; they are bordered above by the two lateral lips of the cord. The elastic fibres which enter into their composition are given off either from the latter, or from the spinous processes of the second and third dorsal vertebra ; they are directed downwards or forwards, and reach the spinous processes of the last six cervical vertebre, into which they are inserted by so many digitations, ARTICULATIONS OF THE SPINE. 133 becoming confounded with the interspinous ligaments of the neck. The fibres of the two last digitations are few in number, widely separated from one another, and united by many anastomosing branches, which make them appear as a kind of wide network. The lamine of the cervical ligament are in relation, outwardly, with the superior branch of the ilio-spinal ligament the transverse spinous muscle of the neck, and the great complexus. : (This important structure, which is in reality the mechanical stay and support of the heavy head and neck of quadrupeds, and is usually termed the ligamentum nuche, is all but absent in Man, being represented in him by a thin narrow band, or rather two thin planes of fibres, the ligamenta subflava. It is described by Leyh as if there were not two portions, and that excellent anatomist does not appear to insist sufficiently on the difference between the dorso-nuchal and the dorso-lumbar divisions. Percivall, who almost entirely neglects the ligaments, also makes no distinction. The difference in structure, elasticity, and situation, warrants the distinction made by Chauveau. As already indicated, the function of this ligament, and more particularly of its nuchal division, is to maintain the head and neck in their natural position during repose, and to allow the most extensive movements at other times. ) ; b. Interspinous ligaments (Fig. 80, 3).—Fibrous lamine fill the inter- spinous spaces, and are attached, before and behind, to the opposite borders of the spimous processes which they unite; they are continued below by the interlamellar liga- ments, forming two lateral planes which are applied against each other, like the lamine of the cervical ligament, and covered outwardly by the transverse spinous (dorsalis colli) muscle. In the region of the neck, the interspinous ligaments ave yellow and elastic. In the dorso- lumbar region, they are formed by fasciculi of white fibrous tissue, loosely united to each other at their extremities, and directed very obliquely backwards and downwards. In consequence of this disposition, and notwithstanding their in- extensibility, they permit the separation of the iyreRyERTEDRAL ARTICULA- spinous processes. Their lateral surfaces are TIONS. divided by a layer of grey elastic fibres, which a, , c, Bodies of three dorsal cross like an X the direction of the preceding vertebra divided longitudi- fasciculi. Very abundant in the anterior moiety nally and vertically to show vos : (1, 1) a section of the in- of the dorsal region, these fibres operate, by their —tgtvertebral discs; 2, Super- proper elasticity, in bringing the spinous pro- spinous dorso-lumbar liga- cesses towards each other. ment; 3, Interspinous liga- c. Interlamellar, or interannular ligaments— ments 4, Ce pnea SCOT Situated, as their name indicates, between the ae cayenls : coms é processes vertebral laminew, and divided into two lateral in the dorsal region. moieties, these ligaments appear to be produced by the two fibrous planes of the preceding ligaments, which, on arriving at'the base of the spinous processes, separate from one another to be carried outwards. Their anterior border is inserted into the posterior margin of the vertebral lamina in front. Their posterior border is fixed to the anterior border and inferior face of the lamina behind. Their superior face is in relation with some spinal muscles, and their inferior face is in contact with the dura mater. Outwardly, they are confounded with the capsules proper 12 134 THE ARTICULATIONS. to the articular processes. Yellow and elastic in the cervical region, these ligaments are white and inelastic in the dorso-lumbar region. ; d. Capsules proper to the articular processes (Fig. 81, 5).—Each anterior articular process is maintained against the corresponding posterior process by a direct band: this is a peripheric capsule attached around the diarthrodial facets, doubled internally by a synovial membrane which facilitates their gliding, and covered, outwardly, by the insertions of some spinal muscles. These capsules, yellow and elastic in the cervical, are composed of white fibrous tissue in the dorso-lumbar region. Very developed at the neck, in consequence of the thickness of the articular tubercles they envelope, they become reduced, near the middle of the back, to sume fibres which cover, outwardly, the diarthrodial facets in contact. CHARACTERS PROPER TO SOME INTERVERTEBRAL ARTICULATIONS.—1. Inter- coccygeal and sacro-coccygeal articulations.—These are constructed after the same type as the other spinal articulations, except that they are appropriate to the rudimentary state of the vertebre they unite. The coccygeal bones only come in contact by their bodies, their spinal lamine being reduced to the merest traces, or are altogether absent. The anterior and posterior articular surfaces of each vertebra are convex, and the interarticular fibro-cartilages, hollow on both faces, resemble a biconcave lense. With regard to the peripheral bands, they are represented by a bundle of longitudinal fibres spread over the surface of the bones, which they envelope in a common sheath. 2. Intersacral articulations—The sacral vertebre being fused into one piece—the os sacrum—there is no occasion to study the true articulations in this region. It may be remarked, however, that the superspinous dorso- lumbar ligament is continued on the sacral spine, and that there exist be- tween the processes formed by this spine veritable interspinous ligaments. 3. Sacro-lumbar articulation.—In this articulation, the great thickness of the fibro-cartilage is to be remarked; and, in addition, that the last lumbar vertebra corresponds with the sacrum not only by its body and articular processes, but also by the oval and slightly concave facets shown on the posterior border of its transverse processes, which are adapted to analogous slightly-convex facets on the sides of the base of the sacrum. The bundles of fibres thrown from one bone to another from around these sacro- transversals (real planiform diarthroses) maintain the articular surfaces in contact, and cover, outwardly, the synovial membrane which facilitates their gliding. 4. Articulation of the two last lumbar vertebree.—This is distinguished by the presence, between the transverse processes, of a planiform diarthrosis like that of the sacro-transversal just noticed. These two articulations are only found in Solipeds. 5. Atlo-axoid articulation.—This is so far removed by its conformation and special uses from the other intervertebral articulations, that it will be described as an extrinsic articulation of the head and spine. (See the Articulations of the Head.) Tux Movements or tHE SPINE IN GENERAL.—Each intervertebral articula- tion is the seat of very obscure movements, whose separate study offers little interest. But these movements, when conjoined with those of the other articulations, result in bending the whole spinal stalk in a somewhat marked manner, and producing either the flexion, extension, or lateral inclination of this flexuons column. ; When flexion takes place, the spine is arched upwards, the common inferior ligament is relaxed, the spinous processes separate from one ARTICULATIONS OF THE HEAD. 135 another, and the superspinous ligament, becoming very tense, soon imposes limits to this movement, Extension is effected by an inverse mechanism, and is checked by the tension of the common inferior ligament and the meeting of the spinous processes, Lateral inclination takes place when the spine bends to one side. This movement is very easily executed in the cervical and coceygeal regions, but is arrested by the ribs and the costiform processes in the dorso-lumbar region. A circumflex movement is possible at the two extremities of the vertebral column—neck and tail; for they pass easily from extension to lateral inclination, and from this to flexion, etc. _ Owing to the elasticity of the intervertebral fibro-cartilages, the spine is endowed with a very limited amount of rotation, or rather of torsion. For the special study of the movements of each spinal region, reference must be made to what has been already said (page 29) regarding the mobility of this column. In the Oz the intervertebral dises are much thicker than in the Horse. The common inferior vertebral ligament is very strong in the lumbar region. The superspinous dorso-lumbar ligament is composed of yellow elastic tissue. The cervical ligament is much more developed than in Solipeds, in consequence of the greater weight of the head ; and it presents a conformation altogether special, which M. Lecoq has made known in the following terms: “On leaving the withers, the superspinous ligament ceases to cover the head of the spinous processes, and extends from each side in a wide and strong band, taking points of attachment on the sides of the processes, and becoming separated, on leaving that of the first dorsal vertebra, into two parts—a superior and inferior. The first reaches the cervical tuberosity in the form of a thick cord united to the cord of the opposite; the other thins off into a band which is attached to the posterior half of the spinous process of the axis and to that of the third and fourth vertebre. A production of the same nature, an auxiliary to the principal portion, leaves the anterior border of the spinous process of the first dorsal vertebra, and is attached to that of the fourth, fifth, sixth, and seventh vertebra. The superior border of this auxiliary liga- mentous production is concealed between the two lamina of the principal ligament.”? The Pig, remarkable for the shortness of its neck and the limited movements of this region, does not show any cervical ligament, properly so called. It is replaced by a superficial fibrous raphé extending from the occipital bone to the spinous process of the first dorsal vertebra. peer . The Cat has no cervical ligament, and shows, instead, a raphé like the Pig. In the Dog the ligament is reduced to a simple cord, continued from the dorso-lumbar ligament, and which goes no further than behind the spinous process of the axis, In the Cat the interspinous ligaments are replaced by small muscular fasciculi; with the Dog this substitution only takes place in the cervical region. The lamine of the first coccygeal vertebrze possess the principal characters which distinguish perfect pee and are united by vestiges of the articular bands which exist in the other regions o the spine. Arriete Il.—AnrticuLations of THE Heap. We will first study the two extrinsic articulations which, are the centre of the movements of the head on the spine—the atlo-axoid and oecipito-atloid articulations. Afterwards, we will pass to the examination of the joints which unite the different bones of the head. 1. Atlo-axoid Articulation. uffices to remove the soft parts from around the articulation to ion.—lt 8 ‘ ace : ( Peeparaizon: the interspinous, and the inferior odontoid ligament. To examine expose the interannular, ‘ Journal de Médecine Vétérinaire’ (Lyons, 1848), p. 122, 136 THE ARTICULATIONS. the superior odontoid ligament and the synovial membrane, one half the atlas and axis must be separated by sawing longitudinally through them from one side to the other.) This may be considered as the type of the trochoides. ; Articular surfaces —To form this articulation, the axis offers its odontoid pivot and the undulated diarthrodial facets at its base. The atlas opposes to the pivot the concave semicylindrical surface hollowed on the superior face of its body; and for the lateral undulated facets it has analogous facets which are cut on the transverse processes, on each side of the vertebral canal. Mode of wnion.—1. An odontoid, or odonto-atloid ligament; 2. An inferior atlo-axcid ligament; 3. A superior ditto; 4. A fibrous capsule. a. Odontoid ligament (Fig. 81, 3).—Continued to the common superior vertebral ligament, very short and strong, flattened from above to below, and triangular in shape, the odontoid ligament is composed of glistening white fibres, fixed behind in the superior channel of the odontoid process, and inserted in front on the transverse ridge which separates the superior face from the inferior arch of the atlas, as well as on the imprints situated in front of this ridge. This ligament is covered, on its lower face, by the synovial membrane of the articulation; and by its upper surface is in contact with the spinal dura mater. It sends some bands within the condyles of the occipital bone. b. Inferior atlo-axoid ligament.—This is a wide, thin, and nacrous- looking band, extending from the inferior face of the axis to the inferior tubercle of the atlas, and covered by the long muscle of the neck; it is united to the synovial membrane by its deep face, and confounded on its borders with the fibrous capsule to be immediately described. c. Superior atlo-axoid ligament.—This exactly represents the inter- spinous ligaments of the other cervical articulations. Yellow, elastic, and formed like the two lateral bands, it is continuous, laterally, with the capsular ligament. d. Capsular ligament.—This, it may be said, is only the interlamellar ligament proper to the atlo-axoid articulation. It commences from the sides of the preceding ligament, and becomes united to the inferior atlo- axoid one, after contracting adhesions with the borders of the odontoid ligament. In this way it encloses the articulation and the spinal canal. Before and behind, it is attached to the anterior or posterior margin of the bones it unites, Its external face is in contact with the great oblique muscle of the head; its internal responds, in its inferior half, to the articular synovial membrane, and its superior moiety to the spinal dura mater. (Leyh describes this ligament as the interannular. Synovial membrane.—This lines the odontoid ligament, the atlo-axoid ligament, and the articular portion of the peripheral capsule. Movements.—Rotation, the only movement possible in the atlo-axoid articulation, is effected in the following manner: the axis remains fixed, and the first vertebra, drawn to one side chiefly by the great oblique muscle, rotates on the odontoid pivot, carrying the head with it. Tn the Dog and Cat the odontoid ligament is replaced by three particular ligaments : 1 Two lateral cords, rising in common from the summit of the odontoid process, and inserted, each on its own side, within the condyles of the occipital bone; 2, A transverse ligament, passing over the odontoid process, which it maintains in its place against the inferior arch of the atlas, and is attached by its extremities to the superior face of the latter. A small synovial capsule facilitates the gliding of the odontoid process beneath this ligament. The articular synovial membrane always communicates with that of the Occipito-atloid articulation. In the P’g the disposition is nearly the same as in the Carnivora ARTICULATIONS OF THE HEAD. 2. Occipito-atloid Articulation. 137 (Preparatton.—Dissect away all the soft parts that pass from the neck to the head and cover the articulation, and more particularly the flexor, the recti, and the small oblique muscles of the head. To expose the synovial membranes, open the sides of the capsular - ligament.) This is a condyloid articulation. Articular surfaces.—In the atlas, the two cavities which replace the anterior articular processes and the heads of the other vertebrae; in the occipital bone, the two condyles flanking the sides of the occi- pital foramen. Mode of union.—A single capsular ligament en- velopes the entire articulation ; it is attached by its anterior border to the margin of the occipital con- dyles, and by its posterior to the anterior contour of the atlas. Thin and slightly elastic in its inferior half, this ligament presents, superiorly, four reinforcing fasciculi: two middle, which intercross in X—from whence the name “ cruciform,” sometimes given to this ligament (Fig. 81, 1, 1); and two lateral, which pass from the sides of the atlas to the base of the styloid processes (Fig. 81, 2, 2). It is lined within by the synovial membranes, and is enveloped externally by a large number of muscles, which protect the articu- lation and greatly strengthen iteverywhere. Among these may be particularly noticed the straight muscles of the head, the small oblique, and the great com- plexus. There is also the cord of the cervical liga- ment. Synovial membranes.—These membranes are two in number, one for each condyle and corresponding atloid cavity. Sustained above, below, and outwardly ‘by the capsular ligament, they are related inwardly to the dura mater and tothe fibrous tractus which, from the odontoid ligament, is carried to the in- ternal face of the occipital condyles. Movements.—Extension, flexion, lateral inclination, and circumduction, are the possible movements of the occipito-atloid articulation. In the Pig, Dog, and Cat this articulation, strengthened as it is by the capsular and odontoido-occipital ligaments already mentioned, has only one synovial capsule. 3. Articulations of the Bones of the Head. If we except the articulation which unites the inferior jaw to the cranium—the temporo-maxillary— and the hyoideal articulations, it will be found that all the bones of the cranium and face are united to each other by synarthrosis, forming the different kinds of sutures already generally described (page 128). Nothing is to be gained by entering into more detail ATLO-OXOID AND OCCIPI- TO-ATLOID ARTICULA- Trons. The upper arch of the atlas has been removed to show the odontoid ligament. 1, 1, Middle accessory fas- ciculi; 2, 2, Lateral fasciculi of the capsular ligament of the occipito- atloid articulation; 3, Odontoid ligament; 4, Interspinous ligament uniting the second and third vertebra of the neck ; 5, Fibrous capsule uniting the articular processes of these verte- bra.—a, Anterior in- ternal foramen of the atlas converted into a groove by the section of the bone; B, 3, Verte- bral foramina of the atlas; c, ¢c, Foramina replacing the anterior notches of the axis. 138 THE ARTICULATIONS. with regard to these articulations, as it will be found sufficient to call to mind the topographical description of each piece entering into their formation. 4. Temporo-masillary Articulation. (Preparation.—Remove the masseter muscle and the parotid gland. Saw through the head about the middle line. Open the articulation externally to exhibit the inter- articular meniscus.) The lower jaw, in its union with the cranium, constitutes a double condyloid articulation. Articular surfaces.—With the temporal bone, these are the condyle, the glenoid cavity, and the supracondyloid process which exists at the base of the zygomatic process. The glenoid cavity is not lined by cartilage, and appears to be merely covered by synovial membrane. With the maxillary bone there is the oblong condyle situated in front of the coronoid process. Interarticular fibro-cartilage.—The articular surfaces just named are far from fitting each other accurately; this is only accomplished by the interposition of a fibro-cartilaginous disc between the temporal and maxillary bones. This disc isa kind of irregular plate, flattened above and_ below, thicker before than behind, and moulded on each of the diarthrodial surfaces it separates. Its superior face, therefore, presents: in front, a cavity to receive the condyle of the temporal bone; behind, a boss which is lodged in the glenoid cavity. The inferior face is hollowed by an oblong fossa in which the maxillary con- dyle is lodged. Mode of union.—A fibrous envelope—a true ; capsular ligament—surrounds the articulation, pec i conte a is stiabhed by its borders to the margin of 1, Interarticular fibro-cartilage; the articular surfaces it unites. Formed, out- 2, External fasciculus of the wardly, by a thick fasciculus of white vertical capsular ligament.—a, Base of fibres (Fig. 82, 2), this ligament becomes grey- we ce cule He ish-coloured and elastic for the remainder of Mastoid process; p, External its extent, and greatly diminishes in thickness, auditory hiatus. especially in front. Its inner face is lined by the synovial capsules, and adheres to the cir- cumference of the interarticular fibro-cartilage. Its external face responds, in front, to the temporal and masseter muscles; behind, to the parotid gland; inwardly, to the external pterygoid muscle; and outwardly, to a fibrous expansion which separates it from the skin. (Leyh mentions a lateral external and a posterior ligament for this articulation, but Chauveau and Rigot evidently look upon these as portions of the capsular.) Synovial membranes. —This articulation has two synovial sacs, one above the other, which are separated by the fibro-cartilaginous disc. Afovements.—The temporo-maxillary articulation is the centre of all the movements performed by the lower jaw. These are: depression, elevation, lateral motion, and horizontal gliding. The lower jaw is depressed when it separates from the superior one, and is elevated when it approaches this. These two opposite movements are executed by a mechanism of such great simplicity that it need not be Fig. 82. ARTICULATIONS OF THE HEAD. 139 described here. Lateral movements take place when the inferior extremity of the jaw is carried alternately to the right and left. It then happens that one of the maxillary condyles, taking with it the fibro-cartilage, is brought into contact with the temporal condyle, while the other is imbedded in the glenoid cavity of the opposite side. The horizontal gliding is effected from behind to before, or vice versd. In the first case, the two maxillary condyles are carried at the same time under the temporal condyles, bearing with them the fibro-cartilages. In the second case, they are drawn into the glenoid cavities, and rest against the supracondyloid eminence, which prevents their going further. It will be understood, after this brief description, that the presence of the fibro-cartilages singularly favours the lateral movements and horizontal gliding of the lower jaw. In the Pig the temporo-maxillary articulation is formed after the same type as that of rodents, and allows very extensive movements from before to behind; a circumstance due to the complete absence of the supracondyloid eminence. In the Dog and Cat the maxillary condyle is exactly fitted into the temporal cavity. This disposition, in giving great precision to the movements of depression and elevation, restrains in a singular manner the lateral and horizontal gliding motions. The inter- articular fibro-cartilage is extremely thin in these animals. 5. Hyoideal Articulations. (Preparation.—Disarticulate the lower jaw, and dissect away from the right of each articulation the muscles that may conceal the view.) These are of two kinds: eatrinsic and intrinsic. The first comprise the two temporohyoideal articulations ; to the second belong the joints which unite the different pieces of the hyoid bone—the interhyoideal articulations. Tremporo-HyorpEaL ARTICULATIONS.—These are two amphiarthrodial joints, in the formation of which cach great branch of the hyoid bone opposes its upper extremity to the hyoideal prolongation lodged in the vaginal sheath of the temporal bone. An elastic cartilage, from 4-10ths to 6-10ths of an inch in length, unites the two bones in a solid manner; and it is owing to the flexibility of this cartilage that the hyoid bone can move entirely on the temporal bones. InreruyorweaL ArticuLations.—A. The great branch articulates with the small one by an amphiarthrosis analogous to the preceding. To form this articulation, these two pieces of bone are joined at an acute angle through the medium of a more or less thick cartilaginous band, in the centre of which there is often a little bony nucleus. This cartilage is elastic and flexible, and permits the opening and closing of the articular angle at the summit of which it is placed. B. Each small branch is united to the body of the hyoid bone by an arthrodial articulation. The articular surfaces are: for the hyoideal branch, the small cavity terminating its inferior extremity; for the body, the rounded lateral facet situated at the origin of the cornu. These surfaces are covered by cartilage, and enveloped by a small synovial sac and a peripheral fibrous capsule. They can glide on each other in nearly every direction, (Median and superior hyoideal capsular ligaments are described by Leyh as sometimes present. The latter unites the upper and middle branches, and the former the middle with the inferior branches. They are absent when these branches are confounded with the superior ones.) 140 THE ARTICULATIONS. Articte IIJ.—AnrticuLaTions oF THE THORAX. These are also divided into extrinsic and intrinsic. The first, named costo-vertebral, unite the ribs to the spine. The second join the different pieces of the thorax together; they comprise: 1, ‘I'he chondro-sternal articulations ; 2, Chondro-costal articulations; 3, The articulations of the costal cartilages with each other; 4, The sternal articulation peculiar to the larger Ruminants and the Pig. All these joints will be first studied ina particular manner, then examined in a general way as to their movements. 1. Articulations of the Ribs with the Vertebral Column, or Costo-vertebral Articulations. Each rib responds to the vertebral column by two points—its head and its tuberosity. The first is received into one of the intervertebral cavities hollowed out on the sides of the spine, and is therefore in contact with two dorsal vertebre; the second rests against the transverse process of the posterior vertebra. From this arrangement arises two particular articulations belonging to the arthrodial class, which are named costo-vertebral and costo- transverse. = CosT0-VERTEBRAL ARTICULATIONS.—Articular surfaces.— Pertaining to the rib, we have the two convex facets of the head, separated from each other by a groove of insertion and covered by a thin layer of cartilage. On the vertebra, the concave facets which by their union form the inter- vertebral cavity; these facets are also covered with cartilage, and separated, at the bottom of the cavity by the corresponding intervertebral disc. Mode of union.—1. An interarticular ligament (Figs. 83, 2; 84, 1), im- planted in the groove of insertion of the head of the rib, and attached to Fig. 83. ARTICULATIONS OF THE RIBS WITH THE VER- ARTICULATIONS OF THE RIBS WITH THE VER- TEBR.Z, AND OF THESE WITH EACH OTHER TEBR.Z, AND OF THESE WITH EACH OTHER (UPPER PLANE). (INFER“OR PLANE). 1, Spinal canal, upper face, showing the 1, Interarticular costo-vertebral ligament 3 common superior ligament; 2, Interar- 2, 3, 4, Fasciculi of the stellate, or in- ticular costo-vertebral ligament; 3, Inter- ferior costo-vertebral ligament ; 5, Common osseous costo-transverse ligament; 4, Pos- inferior vertebral ligament. terior costo-transverse ligament. the superior border of the intervertebral disc, which it encircles upwards and inwards, to unite on the median line with the ligament of the opposite side. 2. An inferior peripherai ligament (Fig. 84, 2, 3, 4), flat above and below, thin and radiating (whence it is often named the stellate ligament), formed of three fasciculi which are fixed in common on the inferior face of ARTICULATIONS OF THE THORAX. 141 the head of the rib, and in diverging are carried over the bodies of the two vertebree and the intervertebral disc. Lined above by the synovial mem- branes, this ligament is covered below by the pleura. (Leyh includes a capsular ligament for the head of the rib and another for the costal tuberosity. He probably viewed the synovial membrane of these articula- tions as such.) Synovial membranes.—Two in number, these are distinguished into anterior and posterior, lying against each other, and separated in part by the interarticular ligament they cover. Supported below by the stellate ligament, above they are directly in contact with the small supercostal muscles, and with vessels and nerves. CostTo-TRANSVERSE ARTICULATIONS.—Articular surfaces.—In the rib, the diarthrodial facet cut on the tuberosity. In the vertebra, the analogous facet on the outside of the transverse process. Mode of union.—T wo ligaments bind this articulation: 1, The posterior costo-transverse ligament (Fig. 83, 4), a white fibrous band attached by its extremities behind the tranverse process and the costal tuberosity, lined by synovial membrane, and covered by the transverse insertions of several spinal muscles; 2, The anterior costo-transverse, or interosseous ligament (Fig. 83, 3), a fasciculus of short, thick, white fibres, fixed on the anterior surface of the transverse process near its base, and in the rugged excavation on the neck of the rib. This ligament is invested, posteriorly, by the synovial membrane, and covered in front by pads of’ adipose tissue which separate it from the costo-vertebral articulation. Synovial membrane.—This is a small particula. capsule kept apart from the posterior synovial membrane of the costo-vertebral articulation by the costo-transverse interosseous ligament. CHARACTERS PECULIAR TO soME CosTO-VERTEBRAL ARTICULATIONS.— 1. The first, and sometimes the second, costo-vertebral articulation has no interosseous ligament, and only exhibits one synovial membrane. The intervertebral cavity which concurs in forming the first is often excavated between the last cervical and first dorsal vertebrae. 2. The two or three last costo-transverse articulations are confounded with the corresponding costo-vertebral joints. They have no proper serous membrane, but the posterior synovial membrane of the latter is prolonged around their articular surfaces. 2. The Chondro-sternal or Costo-sternal Articulations. (Preparation—To show the articulation of the ribs with the cartilages, these with the sternum, and the cartilages with each other, carefully remove the pleura, the triangular muscle of the sternum, the diaphragm, the transverse muscle of the abdomen, then the pectorals, the great oblique, the transversalis of the ribs, and the intercostal muscles. ) The first eight ribs, in resting upon the sternum by the inferior extremity of their cartilages, form eight similar arthrodial articulations. Articular surfaces.—Each sternal cartilage opposes to one of the lateral cavities of the sternum the convex and oblong facet at its lower extremity. Mode of union.—The diarthrosis resulting from the union of these two surfaces is enveloped everywhere by bundles of white, radiating, fibrous tissue, which constitute a veritable ligamentous capsule. The superior part of this capsule, known as the stellate or superior costo-sternal ligament, is covered by the triangular (sterno-costalis internus) muscle; it is joined to a fibrous cord lying on the superior face of the sternum, and which 142 THE ARTICULATIONS. is confounded in front with that of the opposite side. The inferior portion, the inferior stellate or costo-sternal ligament, is in relation with the pectoral muscles, ay . Synovial capsule.—There is one for each articulation. Characters proper to the first costo-sternal articulation—The first costo- sternal articulation is not separated from its fellow of the opposite side; so that these two joints are, in reality, only one, and the two cartilages lying close to each other correspond by a small diarthrodial facet, continuous with that for the sternum. The two sternal facets are inclined upwards, and confounded with one another. Only one synovial cavity exists for this complex articulation, which unites the two first ribs to each other and to the sternum. 3. Chrondo-costal Articulations uniting the Ribs to their Cartilages. These are synarthrodial articulations whose movements are very obscure. They are formed by the implantation of the cartilages in the rugged cavities the ribs present at their inferior extremities. The solidity of these articu- lations is assured by the adherence of the fibro-cartilage to the proper substance of the ribs, and by the periosteum which, in passing from the bone to the cartilage, plays the part of a powerful peripheral band. In the Ox, the sternal ribs, in uniting with their cartilages, form a veritable ginglymoid diarthrosis, whose movement is facilitated by a small synovial capsule. 4, Articulations of the Costal Cartilages with each other. The ribs, attached to each other by means of the intercostal muscles, are not united by real articulations; neither are their cartilages of prolongment. But the asternal cartilages are bound together by a small yellow elastic ligament, which is carried from the free extremity of each to the posterior border of the preceding cartilage; the anterior border of the first asternal cartilage is directly united to the posterior border of the last sternal cartilage, through the medium of the perichondrium and very short ligamentous bands. This same asternal cartilage is also bound to the inferior face of the xiphoid appendage by a small white ligament (the chondro-xiphoid), under which passes the anterior abdominal artery. 5. Sternal Articulation peculiar to the Ox and Pig. It has been already shown that in these animals the anterior piece of the sternum is not consolidated with the second portion. The two are united by a diarthrodial articulation ; and for this purpose the anterior presents a concave surface, the posterior a convex one. Bundles of peripheral fibres firmly bind them to each other, and a special small synovial capsule facilitates their movements, which are very limited. 6. The Articulations of the Thorax considered in a general manner in regard to Movements, The thorax can increase or diminish in diameter in an antero-posterior and a transverse direction; whence arises the dilatation and contraction of this cavity: the inspiratory movements accompanying the entrance of the external air into the lungs, and the expiratory movements expelling the air contained in these organs. The variations in the antero-posterior diameter of the chest being due to changes in the figure of the diaphragm, need not be noticed here. But the transverse variations being the result of the play of the costal arches on the ARTICULATIONS OF THE ANTERIOR LIMBS. 143 spine and sternum, it is advantageous to study the mechanism which presides in the execution of their movements. The costal arches being inclined backwards on the middle plane, the space they inclose in their concavity is not nearly so extensive as if they had been perpendicular to this plane. Owing to their double arthrodial joints, the ribs are movable on the spine, and their inferior extremity, also movable, rests either directly or indirectly on the sternum. Therefore it is that, when they are drawn forward by their middle portions, they pivot on their extremities, and tend to assume a perpendicular direction, which is the most favourable for the largest increase of the space they limit; then there is enlargement of the lateral diameter of the thorax, which signifies dilatation of its cavity. The inverse movement, by an opposite mechanism, causes the contraction of the chest, The ribs are said to be elevated during the forward movement, and depressed when they fall backwards. These expressions, though perfectly applicable to Man, who stands in a vertical position, are not correct when employed in veterinary anatomy. Articte TV.—ArticuLations oF THE ANTERIOR Liss. 1. Scapulo-humeral Articulation. (Preparation.—Detach the limb from the trunk. Remove from the upper extremity those muscles which are inserted in the vicinity of the glenoid cavity of the scapula; turn down from its lower extremity those which are inserted into the superior end of the humerus or a little below, preserving the attachments of their tendons with the capsular ligament. The thin scapulo-humeralis muscle may be allowed to remain in order to show its relations.) \ To constitute this enarthrodial articulation, the scapula is united to the humerus, and forms an obtuse angle which is open behind. Articular surfaces.—In the scapula there is the glenoid cavity, the shallow, oval fossa, elongated in an antero-posterior direction, notched in- wardly, and excavated at its centre or near the internal notch by a small synovial fossette. A ligamentous band, attached to the brim of the cavity, fills up this notch, and is the vestige of the glenoid ligament of man. In the humerus, the articular head, fixed between the large and small tuberosities, is often excavated by a shallow synovial fossette. Mode of union.—One capsular ligament (Fig. 85, 1), a kind of sac having two openings: one inferior, embracing the head of the humerus; the superior, inserted into the margin of the glenoid cavity. This capsule pre- sents in front two supporting fasciculi, which diverge as they descend from the coracoid process to the great and small tuberosities. The aponeurotic expansion thus formed is very thin and loose, so as to allow the two bones to separate to the extent of from +4, to 8, of an inch; but it is far from being sufficiently strong to bind them firmly together. The articulation is, therefore, consolidated by the powerful muscles which surround it, among which may be noticed: 1, In front, the coraco-radial (flexor brachii), separated from the fibrous capsule by an adipose cushion; 2, Behind, the large extensor of the fore-arm and thin scapulo-humeral (teres minor) muscles, whose office appears to be to pull up this capsule during the move- ments of flexion, so as to prevent its being pinched between the articular surfaces; 8, Outwards, the short abductor of the arm and the subspinous (postea spinatus) tendon; 4, Inwards, the wide and strong tendon of the subscapular muscle. In addition to these powerful retaining apparatus, 144 THE ARTICULATIONS. there ig the atmospheric pressure, whose influence is of a certain impor- tance. This may be proved by removing all the surrounding muscles, when it will be found that the capsule is not relaxed, nor are the articular surfaces separated ; to effect this, it is necessary to make an opening in the capsule, so as to allow the air to enter its cavity, when the surfaces immediately separate. : Synovial capsule.—This is very loose, and entirely enveloped by the peripheral capsule, whose internal surface it lines. Movements. —Like all the enarthrodial articulations, the scapulo-humeral permits extension, flexion, abduction, adduction, circumduction, and rotation, These various movements, however, are far from being so extensive as in Man, the arm in the domesticated animals not being detached from the trunk, but being, on the contrary, fixed with the shoulder against the lateral parietes of the thorax. Flexion and extension are the least limited and the most frequently repeated movements; their execution always demands a displacement of the two bones, which are almost equally movable. In flexion, the scapulo-humeral angle is closed, not only because the inferior extremity of the humerus is carried backwards and upwards, but also because the scapula pivots on its superior attachments in such a manner as to throw its glenoid angle forward and upward. tension is produced by an inverse mechanism. During the execution of the other movements, the scapula remains fixed, and the humerus alone is displaced, bringing with it the inferior rays of the limbs. If it is carried outwards, we have abduction, or inwards, adduction ; if the member passes successively from flexion to abduction, and from that to extension, etc., in describing a circle by its lower extremity, then there is circumduction; if it pivots from left to right, or right to left, we have rotation. In the Pig, Dog, and Cat, the synovial membrane is not exactly inclosed by the fibrous capsule, but forms in front a ewl-de-sac, which descends in the bicipital groove to favour the gliding of the coraco-radial tendon. In Man, the scapulo-humeral articulation is disposed as in animals, but it is also protected above by the coraco-acromion roof. For the reasons noted above, this articulation allows of more extensive motion than in animals. As remarked by Cruveilhier, of all the joints in the human body, the scapulo-humeral is that which has the most extensive motion; in movements furward and outward, the humerus can become horizontal; in those of circumduction it describes a complete cone, which is more extensive in front and laterally than behind and inwardly. 2. Humero-radial, or Elbow Articulation. (Preparation—Turn down the inferior extremity of the flexors of the fore-arm, remove the olecranian, epicondyloid, and epitrochlean muscles, taking care not to damage the ligaments to which they somewhat closely adhere.) Three bones concur to form this articulation, which presents a remark- able example of an angular ginglymus: the humerus, by its inferior ex- tremity, and the two bones of the arm by their upper extremities. Articular swrfaces.—The humeral surface, already described at page 74, is transversely elongated, and convex from before to behind. It presents: 1, A median groove excavated by a synovial fossette; 2, An external groove (humeral trochlea) not so deep as the preceding; 3, A kind of voluminous condyle which borders, inwardly, the internal pulley, and whose antero- posterior diameter is much greater than that of the external lip of the trochlea of the opposite side. The antibrachial surface, divided into two portions, is moulded to the humeral surface ; it is, therefore, concave before and behind, and is composed: 1, Of a double external groove; 2, Of an ARTICULATIONS OF THE ANTERIOR LIMBS. 145 internal glenoid cavity, both excavated, on the superior extremity of the radius; 3, A middle ridge re- sponding to the middle groove of the humerus, separating the two preceding surfaces, and prolonged on the ulnar beak, where it forms the sygmoid notch. This ridge shows a small synovial fossette hol- lowed out on the radius and ulna. Mode of union—Three ligaments : two lateral and an anterior. a. The eaternal lateral liga- ment (Fig. 85, 8) is a thick, short, and strong funicle, at- tached above to the crest limit- ing outwardly and posteriorly the furrow of torsion, and in the small cavity placed at the external side of the humeral articular surface. Below, it is inserted into the supero-ex- ternal tuberosity of the radius. Its anterior border is con- founded with the capsular liga- ment, and is margined by the principal extensor of the pha- langes, which derives from it numerous points of attach- ment. By its posterior border it is in contact with the ex- ternal flexor of the metacarpus. Its internal face is lined by synovial membrane, and its external face is only separated from the skin by the anti- brachial aponeurosis and some of the fasciculi from the origin of the lateral extensor muscle of the phalanges. Its super- ficial fibres are vertical, and are continuous, behind, with the arciform ligamentous bands which stretch from the ulna to the radius. Its deep fibres are slightly oblique downwards and forwards. b. The lateral internal liga- ment, also funicular, is longer, but not so strong as the pre- Fig. 85, SCAPULO-HUMERAL AND HUMERO-RADIAL ARTICU- LATIONS, WITH THE MUSCLES SURROUNDING THEM (EXTERNAL FACE). 1, Scapulo-humeral capsular ligament; 2, Short ab- ductor muscle of the arm; 3, Its insertion in the humerus; 4, Insertion of the subspinous muscle on the crest of the great tuberosity; 5, Coraco- radial muscle; 6, Its tendon of origin attached to the coracoid process; 7, Its radial insertion con- founded with the anterior ligament of the ulnar articulation; 8, 8, External lateral ligament of that articulation; 9, Anterior ligament; 10, Aconeus, or small extensor of the fore-arm; 11, Origin of the external flexor muscle of the metacarpus; 12, Short flexor muscle of the fore-arm.—aA, Tuberosity of the scapular spine.—s, Superspinous fossa.—c, Sub- spinous fossa.—D, Convexity of the small trochan- ter,—£, Summit of the trochanter. ceding. It arises from the small tuberosity on the inner side of the 146 THE ARTICULATIONS. superior articular face of the humerus and, widening as it descends, reaches the radius. Its median fibres, which are the longest, are directed vertically downwards to reach the imprints situated below the bicipital tuberosity ; its anterior fibres, curved forwards, are united to the tendon of the coraco- radial muscle, or are confounded with the anterior ligament; the posterior are turned backwards, near their inferior extremities, to join the arciform fibrous fasciculi which inwardly unite the ulna to the radius. The middle fibres of this ligament cover the inferior insertion of the short flexor of the fore-arm and, in part only, that of the long flexor. It is covered by the ulna-plantar nerve and the posterior radial artery and vein. ; c. The anterior or capsular ligament (Fig. 85, 9) is a membraniform band, attached by its superior border above the humeral articular surface, and by its inferior to the anterior margin of the radial surface. By its lateral borders, it is confounded with the funicular ligaments. Its internal half is formed of vertical fibres which descend from the humerus and expand over the radius, where they become united with the inferior tendon of the’ coraco-radial muscle. In its external moiety it is extremely thin, and composed of fibres crossed in various directions. Lined internally by synovial membrane, this ligament is in contact, by its external surface, with , the anterior radial vessels and nerves, the two flexor muscles of the fore-arm, the anterior extensor of the metacarpus, and anterior extensor of the phalanges. The two latter muscles are even attached to it in a very evident manner. The elbow articulation, closed in front and on the sides by the three ligaments just described, has no particular ligaments posteriorly ; but it is powerfully consolidated: there by the olecranian insertion of the extensor muscles of the fore-arm, and by the tendons of origin of the five flexor muscles of the metacarpus or phalanges. Synovial membrane—This membrane is very extensive and, stretched out on the internal face of the before-mentioned ligaments, forms behind three great culs-de-sac of prolongment : a superior, occupying the olecranian fossa, and covered by a fatty cushion, as well as by the small extensor muscle of the fore-arm;1! two lateral, which descend from each side of the ulnar beak, and are distinguished as internal and external ; the first li, the tendon of the external flexor of the metacarpus ; the second facilitates the play on the upper radial extremity of the four flexor muscles of the foot or digits, and which are attached in common to the epitrochlea. This synovial sac also furnishes the radio-ulnar articulation with a diverticulum which descends between the bones of the fore-arm to below the adjacent diar- throdial facets. Movements. —Flexion and extension. In flexion, the two bones do not approach each other directly, the inferior extremity of the radius deviating a little outwards. This ig due more to the slight obliquity of the articular grooves than to the difference in thickness existing between the external and internal extremities of the humeral surface. Extension is limited by the reception of the beak of the olecranon in its fossa, and by the tension of the lateral ligaments; so that the two rays cannot be straightened on one another in a complete manner, or placed on the same line. In the Dog and Cat, the external lateral ligament is very thick, and forms in its 1 Some grey elastic fibres which cover this cul-de-sac externally, have been wrongly described as @ posterior membraniform ligament. = ARTICULATIONS OF THE ANTERIOR LIMBS. 147 inferior moiety a fibro-cartilaginous cap which is fixed on the ulna and radius, and united in front to the annular ligament of the superior radio-ulnar joint. This cap, with the last- named ligament, completes the osteo-fibrous ring in which the superior extremity of the radius turns. The internal lateral ligament is inserted by two very short fasciculi into the ulna and inner side of the head of the radius. A third fasciculus, deeper and median much more developed than the first, and covered by the inferior insertion of the flexors of the fore-arm, descends between the radius and ulna to the posterior face of the former, and is there inserted near the inferior attuchment of the external ligament, which it appears as if about to join. In Man, the elbow articulation is formed nearly on the same plan as that of the Dog and Cat. The radius and ulna move together when the fore-arm is flexed and extended on the humerus. 8. Radio-ulnar Articulation. Articular surfaces—The two bones of the fore-arm correspond by diarthrodial and synarthrodial surfaces. a. The diarthrodial surfaces consist of four undulated, transversely elongated facets, two of which are radial and two ulnar. The first border, posteriorly, tho great articular surface forming the elbow joint; the second are situated beneath the sigmoid notch. b. The synarthrodial surfaces are plane and roughened, and are also two on each bone: one, superior, extends below the diarthrodial facets to the radio-ulnar arch; the other, inferior, more extensive, occupies all the anterior face of the ulna from this arch; on the radius it forms a very elongated triangular imprint which descends to the lower fourth of the bone. See pages 75, 76. Mode of wnion.—T wo interosseous and two peripheral ligaments. a. The interosseous ligaments, interposed between the synarthrodial surfaces, are composed of extremely short white fibres passing from one to the other surface, and which are endowed with a very remarkable power of resistance. The inferior always ossifies a long time before the animal is full grown: a circumstance which caused the older veterinary anatomists to describe, and with some show of reason, the radius and ulna as a single bone. Ossification of the superior ligament is very rare. b. The peripheral bands are bundles of arciform fibres which, from the uk of the olecranon to the radio-ulnar arch, leave the lateral faces of the ulna to pass, some inwards, others outwards, to the posterior face of the radius. The fibres of the external ligament are confounded with the external humero-radial ligament. The internal fibres are united to the internal humero-radial ligament, and to the small ulnar tendon belonging to the short flexor of the fore-arm. Analogous fibres are found beneath the radio-ulnar arch; but they are much shorter and less apparent. (This is the external transverse radio-ulnar ligament of Leyh.) Movements.—Very obscure in youth; nearly null when consolidation of the two bones takes place. In the Oz, ossification of the superior interosseous ligament is constant at adult age. ‘ In the Dog and Cat, we have already seen (p. 87) that the radius and ulna are not fused to each other, but remain independent during life. They are united in their middle portion by an interosseous ligament, and join by diarthrosis at their two extremities. These animals therefore exhibit: 1, An dnterosseous ligament; 2, A superior radio-ulnar articulation ; 3, An inferior radto-ulnar articulation. Interosseous ligament.—lt is composed of very resisting white fibres, attached by their extremities to the bodies of the bones. Notwithstanding their shortness, they are loose enough to allow movements taking place between the radio-ulnar articulations. Superior radio-ulnar artic ulation.—This is a trochoid articulation, which only allows movements of rotation or pivoting. 14s THE ARTICULATIONS. in the ulna, the small form this articulation are: PY ire 2RdTUs, fr ‘ é oe ee d in the lateral sense, and semicircular ; sigmoid cavity, a surface excavate indri -hi ived into the preceding cavity. pre ie eeecer Se anal ligament, a kind of fibrous web Jugs around wnenine the radius, fixed inwardly on the ulna near the inner the superior extremity of , s piel later i ict ty, attached outwardly to the exte r ney ee ian oul confounded superiorly with the anterior ligament of the elbow articulat 5 ‘ we Ben ee he Gee 5 ticulation. This fibrous web, in uniting ; ¢ Fe one be of the pxtaimal humero-radial ligameut, and joining the small sigmoid ag z : F A 5 ; cavity by ts feanl excl. aioe, et aeabraae oak of ele cartilage, im its pony Pronipus portion, ‘he bead oF superior extremity of the radia is also incrusted over its entire contour with u layer of cartilage: a disposition which permits it to glide not only in the concave face of the small sigmoid cavity, but also on the internal face of the two ligaments which complete this cavity. 7 ; Inferior radio-ulnar articulation.—This is also a trochoid articulation analogous to the preceding, but inversely disposed. Thus, the concave articular surface is hollowed on the radius, outside the inferior extremity; the convex surface lies within the ulna, These two facets are very small, and are maintained in contact by a diminutive peripheral fibrous capsule. A strong interosseous ligament, situated under the articular facets, also consolidates this diarthrosis, and concurs by its inferior border to form the antibrachial surface of the radio-carpal articulation, A small synovial capsule is specially devoted to this articulation. Mechanism of the radio-ulnar joints—The play of these two articulations is simultaneous, and tends to the same end; that is, to the execution of the double rotatory movement which constitutes supination and pronation. Supination is when the ulna remains fixed, and the radius pivots on it in sucha manner as to carry its auterior face outwards. Its superior extremity then turns from within forwards, and even from before outwards if the movement is exaggerated, in the articular girdle formed by the small sigmoid cavity of the ulna and the ligaments which complete it. The inferior extremity also rolls on the ulnar facet in describing a similar movement, and the internal tuberosity of this extremity is carried forwards. In the movement of pronation, this tuberosity is brought inwards, and the anterior face of the radius comes forward by an opposite mechanism. The inferior ray of the anterior member being articulated in a hinge-like manner with the radius, it follows that bone in its rotatory movements, the anterior face of the metacarpus looking outwards during supination and forwards in pronation. The radio-ulnar articulation in Man resembles that of the Dog and Cat, the articular surfaces only being larger and the movements more extensive. In supination, the palmar face is turned forward, and the radius, situated on the outer side of the ulna, is in the same direction as the latter. In pronation, on the contrary, the palmar face of the hand looks backwards, and the radius, remaining outwards in its upper part, crosses the ulna in front in such a manner that its lower extremity is placed within the ulna. 4. Articulations of the Carpus. (Preparation.—Remove the tendons from around th rticulati i i sheaths, but taking care of the ligaments.) i ac li These comprise: 1, The articulations uniting the carpal bones of the first row to each other ; 2, The analogous articulations of the second row; 3, The radio-carpal articulation ; 4, The articulation of the two rows with each other; 5, The carpo-metacarpal articulation. ARTICULATIONS WHICH UNITE THE Bonzs or tue First Row 10 EACH orHrr.—These bones, four in number, are joined by the diarthrodial facets on their lateral faces and form small arthrodial articulations! They are maintained in contact by six ligaments, three anterior, and three interosseous. The anterior ligaments ave small flattened bands carried from the fourth pone to the first, from the first to the second, and from that to the third. The first, placed outside rather than in front of the carpus, is covered by the ? The facet uniting the supercarpal to the first b i i i faces, but rather on the anterior part of its Vinenmferenng, neat ne basa ARTICULATIONS OF THE ANTERIOR LIMBS. 149 _ external lateral ligament and the inferior tendon of the external flexor of the metacarpus; the others adhere to the capsular ligament. The inter- osseous ligaments are implanted in the grooves of insertion which separate the diarthrodial facets. One of them, derived from the common superior ligament, unites the first to the second bone. The two others, situated between the three last carpal bones, are confounded with the corresponding anterior ligaments. ARTICULATIONS UNITING THE CarpaL Bones oF THE Szconp Row.— These ave arthrodial articulations, like the preceding, but numbering only two. They are fixed by two anterior and two interosseous ligaments. One of the anterior ligaments joins the first bone to the second, and strongly adheres to the capsular ligament ; the other is entirely covered by the lateral internal ligament, and attaches the two last bones to each other. Of the two inter- osseous ligaments, the second alone is confounded with the corresponding anterior ligament. That which is situated between the two first bones is separated from the anterior ligament by one of the diarthrodial facets between these bones. Rapio-carpaL ARTICULATION.—The inferior extremity of the radius, in becoming united to the upper row of carpal bones, constitutes a diarthrosis which, from the nature of the movements it permits, may be considered as an imperfect hinge joint. Articular surfaces—The radial surface, elongated transversely and very irregular, presents: 1, Outwardly, a wide groove, limited in front by a small glenoid cavity, and bounded, posteriorly, by a non-articular excavation which receives a prolongation of the second bone in the movement of flexion , 2, Inwardly, a condyle, with a more extensive curvature than that of the preceding groove and, like it, completed by a small anterior glenoid cavity. The carpal surface, moulded exactly on the radial, offers depressions corre- sponding to the projections on it, and vice versd. Mode of union—The radio-carpal articulation is bound by three liga- ments which entirely belong to it, and by four strong ligaments that are common to it and articulations which will be studied hereafter. Of the three ligaments proper belonging to the radio-carpal articulation, one forms a thick, rounded funicle, extending from the radius to the fourth bone in an oblique direction downwards and inwards, and concealed by the common posterior ligament. The second (Fig. 87. 5), much smaller, is carried from the supercarpal bone to the external side of the inferior extremity of the radius, and is partly covered by the common external ligament. When the synovial capsule is distended by dropsy, it may form a hernia at the outer side of the carpus, by passing between this small ligament and the common posterior ligament. The third, very delicate, but always present, is deeply situated beneath the last; it is inserted, for one part, into the radius near the first proper ligament, and for the other, into the second bone and the caus! fees ligament which unites the supercarpal to the second bone. Synovial membrane.—After lining these three ligaments and the four great ligaments yet to be described, this membrane is prolonged between the three first carpal bones to cover the superior face of the interosseous ligaments which unite them. It even more frequertly descends into the articulation which joins the supercarpal to the first bone; though it also sometimes happens that this has a particular synovial capsule of its own. ARTICULATION OF THE Two Rows Between Eace Oruer.—Like the preceding, this is an imperfect hinge articulation. 3 150 THE ARTICULATIONS. Articular surfaces—These are two, and are both transversely range very irregular in their configuration, and divided into three portions. e inferior shows: behind, three small condyles placed side by side; in front, two slightly concave facets. The superior corresponds to the first by three glenoid cavities and two convex facets. ; ; a Mode of union.—For this articulation, besides the common great liga- ments, there are three particular ligaments. Two of these are very short, and are situated behind the carpus, underneath the great common posterior ligament, They are readily perceived by removing the capsular ligament, and strongly flexing the carpus. “The strongest extends vertically from the internal bone of the superior row to the second and third bones of the metacarpal row ;, the other descends obliquely from the first bone of the antibrachial row to the second of the inferior row.”—Rigot. 'The third ligament proper, much stronger than the other two, reaches from the supercarpal to the first bone of the inferior row and the head of the external metacarpal bone. It is confounded, outwardly, with the great external lateral ligament; inwardly, with the common posterior ligament. Its posterior border gives attachment to the fibrous arch which completes the carpal sheath. This ligament has also a branch which is fixed on the second bone of the upper row (Fig. 87, 4). ; Synovial membrane.—This lines all the ligaments, and is prolonged above and below, between the carpal bones, to facilitate the gliding of their articular facets. Two upper pro- longations ascend between the three first bones of the antibrachial row to cover the inferior face of the inter- osseous ligaments uniting them. Two other prolong- ations descend between the carpal bones of the second row; the external, after covering the first interosscous ligament, passes between it and the corresponding an- terior ligament, and communicates with the synovial capsule of the carpo-metacarpal articulation. The in- ternal forms a cul-de-sac which rests on the inter- osseous ligament Carpo-MzracarpaL ARTICULATION.—The carpal bones of the second row articulate with the superior extremity of the metacarpal bones, constituting a plani- form diarthrosis. Articular surfaces—These are, on each side, plane CARPAL ARTICULA- TIONS; FRONT VIEW. 1, 1, Anterior liga- ments uniting the carpal bones of each row; 2, 2, Anterior _ ligaments proper to the carpo-metacar- | pal articulation; 3, -Common external ligament; 4, Com- mon internal liga- ment. facets more or less inclined one on the another, and continued between each other The largest is in the middle, and is generally hollowed by a small, shallow, synovial fossette Mode of unton—There are the four great common ligaments, and also six special ligaments: two anterior, two posterior, and two intB cocous, Of the two anterior ligaments (Fig. 86, 2, 2), one is divided into two distinct bands, and unites the second bone to the principal metacarpal; the other, concealed ‘by the external lateral ligament, attaches the first bone to the head of the external metacarpal bone. The two posterior ligaments described by Rigot do not appear to us to be sufficiently distinct from the great ligament to merit a special description. The two interosseous ligaments, completely overlooked by that able ARTICULATIONS OF THE ANTERIOR LIMBS. 151 anatomist, start from the interstices which separate the median metacarpal bone from the lateral metacarpals, and join the interosseous ligaments of the second row; they are thick and short. We have sometimes noted one or other of them to be absent. Synovial membrane.—This communicates, as indicated above, with the synovial capsule of the preceding articulation. It furnishes a superior cud- de-sac which rests on the interosseous ligament interposed between the two last carpal bones of the second row. Two inferior culs-de-sac descend into the intermetacarpal arthrodial articulations. LicaAMENTs cComMoN TO THE THREE PRECEDING ARTICULATIONS, — As before mentioned, these are four in number two lateral, one anterior, and one posterior. a. The external lateral ligament (Figs. 86 and 87, 3) is a thick funicular cord composed of two orders of fibres—a deep- seated and a superficial order, slightly crossed. It leaves the external and inferior tuberosity of the radius, descends vertically to the side of the carpus, transmits a fasciculus to the first bone of the upper row, gives off another fasci- culus which stops at the external bone of the second row, and terminates on the head of the corresponding metacar- pal bone. Traversed obliquely by the lateral extensor of the phalanges, this ligament covers the external carpal bones. In front, it is united to the capsular ligament; near its inferior extremity, it is confounded with the strong ligament which joins the supercarpal bone to the first bone of the inferior row and to the head of the external meta- carpal bone. b. The internal lateral ligament (Fig. 86, 4), analogous to the preceding and situated on the opposite side, is wider and thicker than it. It commences on the internal tube- rosity of the radius, and terminates on the upper extremity of the middle and internal metacarpal bones, after being attached, by two distinct fasciculi, to the third carpal bone of the upper row, and the two last of the metacarpal row. In contact by its external face with the tendon of the oblique extensor muscle of the metacarpus, this ligament responds, by its deep face, to the synovial membranes of the carpus and to the bones to which it is attached. By its anterior border it is united to the capsular ligament, the opposite border is intimately confounded with the pos- terior ligament, from which it is impossible to distinguish it. c. The anterior, or capsular ligament, is a membranous band covering the anterior fage of the carpal articulations. Its superior border is attached to the radius, the inferior is inserted into the superior extremity of the principal metacarpal bone. The two right and left borders are united with the lateral ligaments. Its external face is in contact with the tendons of the anterior extensor muscles of the metacarpus and phalanges. The internal face is lined at certain points by synovial membrane, and adheres in others to the carpal bones and the anterior ligaments binding these to one another. Fig. 87. LATERAL VIEW OF THE CARPAL AR- TICULATIONS, 1, 1, Anterior liga- ments uniting the two rows of carpal bones ; 2, 2, Anterior liga- ments proper to the carpo-meta- carpal articula- tion; 3, Common external _ liga- ment; 4, One ot the ligaments proper to the articulation of the two rows (metacarpo - su- pracarpal); 5, One of the liga- ments proper to the radio-carpal articulation (ra- dio — supracar- pal).—a, Groove on the external surface of thesu- pracarpal bone for the passage of the external flexor of the me- tacarpus, This ligament is composed of transverse 152 THE ARTICULATIONS. fibres more or less oblique, and arranged crosswise; by its amplitude it can adapt itself to the movements of flexion of the knee. ; ; d. The posterior ligament, one of the strongest in the animal economy, covers the posterior face of the carpus, fillmg up the asperities which roughen it, It is inserted: above, on the transverse crest surmounting the articular surface of the radius ; by its middle portion into all the carpal bones ; below, into the head of the principal metacarpal bone, Confounded inwardly with the internal lateral ligament, united outwardly to the band which attaches the supercarpal to the external metacarpal and the second carpal bone of the upper row, this ligament is continued, by its inferior extremity, with the carpal stay (or check ligament) which sustains the perforans tendon. Its posterior face is perfectly smooth, and is covered by the synovial membrane of the carpal sheath. Movements or THE CarpaL ArticuLaTions.—The carpus is the seat of two very extensive and opposite movements—flexion and extension ; to which are added three very limited accessory movements—adduction, abduction, and circumduction. All the carpal articulations do not take an equal part in the execu- tion of these movements, for it is easy to discover that they are chiefly performed in the radio-carpal diarthrosis, and in the imperfect hinge articulation uniting the two rows of carpal bones. Each of these articula- tions participates im the movements of the carpus in nearly the same pro- portions, and; both act in an identical manner. Their mechanism is most simple. is flexion, the first tier of bones rolls backwards on the radius, the inferior row moves in the same sense on the upper, the metacarpus is carried back- wards and upwards, the common posterior ligament is relaxed, the capsular ligament becomes tense, and the articular surfaces, particularly those of the second joint, separate from each other in front. In extension, the metacarpus is carried downwards and forwards by an inverse mechanism. This move- ment stops when the ray of the fore-arm and that of the metacarpus are in the same vertical line. In flexion, these rays never directly approach each other ; the inferior extremity of the metacarpus being always carried outwards. It may also be remarked, that the slight movements of abduction, adduction, and circumduction of the carpus are only possible at the moment when the foot is flexed on the fore-arm, With regard to the planiform diarthrosis articulating the carpal bones of the same row, they only allow a simple gliding between the surfaces in contact ; and with the carpo-metacarpal arthrodia it is absolutely the same. The restricted mobility of these various articulations has but a very secondary influence on the general movements of the carpus ; but it nevertheless favours them by permitting the carpal bones to change their reciprocal relations, and adapt themselves, during the play of the radio-carpal and intercarpal hinges, to a more exact coaptation of the articular planes which they form. In the other animals, the carpal articulations have the same essential characteristics we have noticed in Solipeds, The four principal peripheral bands differ but little in them; though in the Dog and Cat they are lax enough to allow somewhat extensive lateral movements. 5. Intermetacarpal Articulations. Each lateral metacarpal bone articulates with the middle one by means of diarthrodial and synarthrodial surfaces, for the description of which refer to page 82. An interosseous ligament, composed of very short and strong ARTICULATIONS OF THE ANTERIOR LIMBS. 153 fasciculi, is interposed between the synarthrodial surfaces, and binds them firmly together. Its ossification is not rare. The diarthrodial facets are maintained in contact by the preceding ligament, and by the carpal ligaments inserted into the head of the lateral metacarpal bones. The intermetacarpal articulations only allow a very obscure, vertical, gliding movement. In the Oz, there is only one intermetacarpal articulation, which is much simpler than those in the Horse. In the Pg, the four metacarpal bones correspond, at their upper extremity, by means of small diarthrodial facets on their sides. Fibrous fasciculi, derived from the great anterior and posterior ligaments of the carpus, protect these intermetacarpal articula- tions before and behind. Other fibres, situated between the adjacent faces of the metacarpal bones, are real interosseous ligaments. In the Dog and Cat, the four great metacarpal bones articulate with each’ other in almost the same manner as in the Pig, but their mobility is greater. 6. Metacarpo-phalangeal Articulation. (Preparation Turn down the anterior and lateral extensor tendons of the phalanges, after carefully cutting through their attachment with the capsular ligament. Lay open the metacarpo-phalangeal sheath from above to below, and turn down the flexor tendons.) This is a perfect hinge-joint, formed by the inferior extremity of the median metacarpal bone on the one part, and the superior extremity of the upper phalanx and sesamoids on the other. Articular surfaces.—For the metacarpal bone, there are two lateral condyles and a median antero-posterior eminence; for the first phalanx, two glenoid cavities and an intermediate groove prolonged posteriorly on the anterior face of the two sesamoids. Divided in this manner into three por- tions, the digital surface is well constituted for solidity, because the pressure transmitted to this region is diminished and diffused by the natural elasticity of the bands which unite these three pieces to each other. Mode of union. The means of union may be divided into two categories: 1, Those which join together the several bones of the inferior surface ; 2, Those which maintain in contact the two opposed articular surfaces. A. The first have received the generic name of sesamoid ligaments, and are six in number: an intersesamoid ligament, which keeps together the two complementary bones of the digital surface; three inferior and two lateral sesamotd ligaments, which unite these bones to the first phalanx. a. The intersesamoid ligament is composed of fibro-cartilaginous substance which appears to be the matrix in which the two sesamoids were developed, as it is spread around these bones, after being solidly fixed on their internal face. Behind, this ligament, in common with the posterior face of the sesa- moids, forms the channel (Fig. 89, 5) in which the flexor tendons glide. In front. it occupies the bottom of the intersesamoid articular groove. b. The inferior sesamoid ligaments, situated at the posterior face of the first phalanx, are distinguished as superficial, middle, and deep. The superficial ligament (Fig. 89, 8), the longest of the three, is a narrow band flattened before and behind. It arises from the middle of the fibro- cartilaginous mass which completes, posteriorly, the superior articular surface of the second phalanx, and slightly widening, ascends to the base of the sesamoids, into which it is inserted by becoming confounded with the intersesamoid ligament. Its posterior face, lined by the synovial membrane of the so-called sesamoid sheath, is covered by the flexor tendons; it partly covers the middle ligament. The middle ligament, triangular and radiating, is composed of three 154 THE ARTICULATIONS. particular fasciculi: two lateral (seen on each side of the superficial liga- ment in Fig. 89, 8), and a median which has been generally confounded with the superficial ligament, although it is clearly distinguished from it by its inferior insertion. Fixed in common to the posterior imprints of the first phalanx, these three fasciculi diverge in ascending to the base of the sesamoids, whére they have their upper insertion. The deep ligament is constituted by two small bands concealed beneath the middle ligament. Thin, short, flattened before and behind, and inter- crossed, these bands are fixed to the base of the sesamoids in one direction, and in the other to the superior extremity of the first phalanx, near the margin of its articular surface. This ligament is lined on its anterior face by the synovial membrane of the articulation.’ ce. The lateral sesamoid ligaments are two thin layers extending from the external face of each sesamoid to the tubercle of insertion on the side of the superior extremity of the first phalanx. They are covered by the digital vessels and nerves, by the fibrous stay detached from the suspensory liga- ment to the anterior extensor tendon of the phalanges, and by the superficial fasciculus of the lateral metacarpo-phalangeal ligament ; they are covered by synovial membrane on their internal face. B. The ligaments destined to unite the two articular surfaces of the meta- carpo-phalangeal joint are four: two lateral, one anterior, and one posterior. a. Each lateral ligament comprises two fasciculi, a superficial and a deep, firmly united by their adjacent faces. The superficial fasciculus commences on the button of the lateral metacarpal bone, attaches itself to the median metacarpal, and descends vertically to terminate at the superior extremity of the first phalanx. It covers the phalangeal insertion of the lateral sesamoid ligament and the deep fasciculus. The latter, attached superiorly in the lateral excavation of the infericr extremity of the principal metacarpal, radiates as it reaches the sesamoid and the superior extremity of the first phalanx, where it is fixed by mixing its fibres with those of the lateral sesamoid ligament. The inner face of this fasciculus is lined by the articular synovial membrane. b. The anterior ligament belongs to the class of capsular ligaments. It is a very resisting membraniform expansion which envelops the anterior face of the articulation. Attached by its upper border to the anterior margin of the metacarpal surface, and by its inferior border to the first phalanx, this expansion is confounded at its sides with the lateral ligaments. It is covered by the extensor tendons of the phalanges, which glide on its surface by means of small serous sacs. Its internal face adheres throughout its whole extent to the synovial capsule. c. The posterior ligament, very appropiately named the suspensory ligament of the fetlock (Figs. 88 , 89, 4), is a long and powerful brace, composed of white fibrous tissue, and often containing fasciculi of fleshy fibres in its texture. Lodged behind the median metacarpal, and between the two lateral meta- carpal bones, this brace is quite thin at its origin, but it soon becomes enlarged, and preserves its great thickness to the extent of its upper fourth. Examined in section, it appears to be formed of two superposed portions which are closely adherent to each other. The superficial portion, the thinnest, commences by three small branches, which are fixed to the first and second * The two bands described by Rigot as forming part of this ligament, belong to the lateral fasciculi of the middle ligament. * It corresponds to the two muscles which, in May, lie alongside the interosseous metacarpal muscles. See the Muscles of the foot. ARTICULATIUNS OF THE ANTERIOR LIMBS. 155 bones of the lower carpal row; the deep portion, much thicker, is attached to the posterior face of the principal metacarpal for about 8-10ths of an inch. It has been wrongly asserted that the suspensory ligament of the fetlock is continuous with the common posterior ligament of the carpus; it is, on the contrary, quite distinct from it. The carpal stay or deep palmar aponeu- rosis of Man, is alone in direct continuity with the common posterior liga- Fig, 88, ment of the carpus. The suspensory ligament of the fetlock is bifid at its inferior extremity ; its two branches, after being fixed into the summits of the sesamoid bones, give origin to two fibrous bands which pass downwards and forwards to become united on each side to the anterior ex- tensor tendon of the phalanges. It is in relation, by its posterior face, with the perforans tendon and its carpal stay; by its anterior face, with the median metacarpal bone, and arteries and veins; by its borders, with two small interosseous muscles, the lateral metacarpal bones, and the digital vessels and nerves. Synovial membrane.—This membrane is pro- longed as a cul-de-sac between the terminal branches of the preceding ligament. It is the distention of this sac which causes the articular swellings vulgarly designated “‘ windgalls.” Movements——The metacarpo-phalangeal articu- lation permits the extension and flexion of the digit, and some slight lateral motion when the movable osseous ray is carried to the limits of flexion. SECTION OF THE INFERIOR: In the Ox, Sheep, and Goat, this articulation consti- tutes a double hinge which resembles the simple gin- glymus of monodactyles. They have three intersesamoid ligaments two lateral to unite the large sesamoids of each digit, and a median which unites the internal sesamoids. The inferior sesa- moidean ligamentous apparatus is far from showing the same degree of development as in the Horse; it is reduced for each digit to four small bands, which remind one very much of the deep ligament of the latter animal, as it has been described by Rigot: two lateral bands pass directly from the sesamoids to the upper extremity of the first phalanx; the other two, situated between the first, inter- ROW OF CARPAL BONES, THE METACARPAL, AND THE SUSPENSORY LIGAMENT OF THE FETLOCK. 1, Os magnum; 2, Common posterior ligament of the carpus; 3, Stay, or band for the perforans tendon; 4, Suspensory ligament of the fetlock; 5, Its super- ficial layer; 6, Its deep fasciculus, 7, Principal metacarpal bone. cross and are confounded with the latter by their ex- tremities.—A lateral sesamoid ligament unites the first phalanx to the external sesamoid. For each digit there are two lateral metacarpo-phalangeal ligaments an external, analogous to that of the Hor-e, but less complicated, is attached by its inferior extremity to the first phalanx only; the other, internal, fixed superiorly in the bottom of the inter- articular notch of the metacarpal bone, is inserted into the inner face of the first phalanx in mixing its fibres with those of the superior interdigital ligament. This latter is situated between the two first phalanges, and is composed of short, intererossed fibres, attached to the imprints which in part cover the internal face of the two first phalangeal bones. In the Sheep there are only traces of this interdigital ligament, and each internal metacarpo-phalangeal ligament gives rise, near its phalangeal insertion, to a fibrous branch which is directed backwards from the interdigital space, and is terminated in the bone of the ergot (or posterior rudimentary digit), which it sustains, The anterior or capsular ligament, single as in Solipeds, unites the two external lateral ligaments. The suspensory ligament, single superiorly, is divided inferiorly into eight branches, two of which are joined to the perforatus tendon to form with it the double Ying through which the two branches of the perforans pass. Four other branches, in 156 THE ARTICULATIONS. pairs, extend to the summits of the sesamoids. That which is sent to each external sesamoid gives off, on the side of the first phalanx, a reinforcing band to the proper Fig. 89, POSTERIOR VIEW OF THE METACARPO- PHALANGEAL AND INTER - PHALAN- GEAL ARTICULA- TIONS; RIGHT LIMB. 1, 3, Outer and inner rudimentary me- tatarsal bones; 2, Perforans tendon extensor of the digit. The two last, profound and median, descend into the interarticular notch of the metacarpal bone, after becoming a single fasciculus , afterwards, they pass between the two internal metacarpo-phalangeal ligaments, and separate from each other in passing downwards and forwards on the inner side of the first phalanx, to join the proper extensor tendon of each digit. In the Pig, Dog, and Cat, for each metacarpo-phalangeal there is: a proper synovial membrane; an intersesamoid ligament; an inferior sesamvid ligament composed of two cross-bands; two small lateral sesamoid ligaments; two lateral metacarpo-phalangeal liga- ments, attached inferiorly to the first phalanx and the sesamoids; an anterior capsular ligument, in the centre of which is found a small bony nucleus, a kind of anterior sesamcid, over which glides one of the branches of the common extensor of the digits. The suspensory ligament is replaced by real palmar interosseous muscles (see the Muscles of the fore-foot). Some fibres situated between the first phalanges of the great digits in the Pig, remind one of the superior interdigital ligament of the Ox. In Man, the cavity in the upper extremity of the first phalanx is completed by a glenoid ligament. The glenoid ligaments of the four first digits are united to each other by a transverse ligament of the metacarpus. The articulations are consolidated by two lateral ligaments. The metacarpo-phalanyeal articulations allow flexion and extension movements, us well as those of abduction and adduction ; but the latter are limited by the lateral ligaments. 7. Articulation of the First with the Second Phalanx, or First Interphalangeal Articulation. (Preparation.—Remove the extensor tendon; throw open the metacarpo-phalangeal sheath, and turn down the flexor tendons.) This is an imperfect hinge-joint. Articular surfaces—On the inferior extremity of the first phalanx, there are two lateral condyles separated by a - groove. On the superior surface of the second phalanx, there are two glenoid cavities and an antero-posterior ridge. The latter surface is completed behind by a glenoidal jibro-cartilage, very dense and thick, which also acts as a ligament. It is attached, in one direction, to the second phalanx, between the superior articular surface and the kind of fixed sesamoid which margins it behind ; in the other, it is inserted into the first phalanx by means of six fibrous bands: two superior, which embrace the inferior, middle, and superficial sesamoid ligaments; two middle and two inferior, which extend to the sides of the inferior extremity of the first phalanx. This fibro-car- tilage is moulded, in front, to the articular surface of the latter bone, and forms, by its posterior face, a gliding and its check ligament ; 4, Suspensory ligament; 5, Gliding surface, or sheath for the flexor tendons, formed by the posterior face of the sesamoid bones, and intersesamoid transverse, and annular ligaments; 6, Section of lateral sesamoid ligament; 7, Lateral fasciculus of the middle inferior sesamoid ligament; 8, Inferior superficial sesamoid ligament; 9, Lateral ligament of the first interphalangeal articulation; 10, Section of the terminal branch of the perforatus tendon; 11, Section of the lateral cartilage of the foot; 12, Postero-inferior surface of navicular bone; 13, Section of lateral car« tilage, plantar cushion, and wing of pedal bone; 14, Perforatus tendon; 15, Perforans tendon. ARTICULATIONS OF THE ANTERIOR LIMBS. 157 surface for the perforans tendon (Fig. 89, 5). It is confounded, laterally, with the two branches of the perforatus, and receives in the middle of its superior border the insertion of the inferior superficial sesamoid ligament. Mode of union.—Two lateral ligaments, to which are added, behind, the fibro-cartilage just described, and in front the tendon of the anterior extensor of the phalanges. These ligaments are large and thick, and passing obliquely downwards and backwards, are inserted, superiorly, into the lateral tubercles on the inferior extremity of the first phalanx. They are attached, beneath, to the sides of the second phalanx. Their most inferior fibres are even prolonged below that point to reach the extremities of the navicular bone, and constitute the posterior lateral ligaments of the pedal articulation. Synovial membrane.— This covers the tendon of the anterior extensor of the phalanges, the lateral ligaments, and the glenoid fibro-cartilage. Behind, it forms a cul-de-sac which extends between the latter and the posterior face of the first phalanx. Movements. This imperfect hinge is the seat of two principal movements: extension and flexion. It also allows the second phalanx to pivot on the first, and permits some lateral movements. In the Ox, Sheep, and Goat, the glenoid fibro-cartilage is confounded with the per- foratus tendon, and is only attached to the first phalanx by two lateral bands. The internal lateral ligament comprises two fasciculi: one, very short, which terminates in the second phalanx; and another, very long, descending to the internal face of the third phalanx. The external is very thin, and is also prolonged to the terminal phalanx; so that the two last interphalangeal articulations of each digit are fixed by twc common lateral ligaments which correspond exactly, by their position and inferior attachments, to the anterior lateral ligaments of the pedal joint of Solipeds. In the Dog and Cat, the glenoid cartilage, also confounded by its posterior face with the perforatus tendon, only adheres to the first phalanx by some cellular bands, The two lateral ligaments pass from the inferidr extremity of the first phalanx to the superior extremity of the second. In the Pig, there is somewhat the same arrangement as in Carnivora. The external lateral ligament is, nevertheless, more like that of the Horse, in its most anterior fasciculi being prolonged to the external extremity of the navicular bone. 8. Articulation of the Second Phalanx with the Third, Second Interphalangeal Articulation, or Articulation of the Foot. To form this imperfect hinge-joint, the second phalanx is opposed to the third, and to the navicular bone. Articular surfaces. —On the inferior face of the second phalanx there are two lateral condyles and a median groove. On the superior face of the third phalanx and the navicular bone, are two glenoid cavities separated by an antero-posterior ridge. The two bones which form this last surface arti- culate with each other by an arthrodia; the navicular bone presents for this purpose an elongated facet on its anterior border; the os pedis also offers an analogous facet on the posterior contour of the principal articular surface. Mode of wnion.—Five ligaments: a single interosseous one which joins the navicular to the pedal bone; and four lateral pairs, distinguished as anterior and posterior. a. Interosseous ligament.—This is formed of very short fibres which are inserted, behind, into the anterior groove of the navicular bone; and in front, into the posterior border and inferior face of the third phalanx. This ligament is lined, on its superior surface, by the synovial membrane, and on its inferior face is covered by the navicular sheath. b. Anterior lateral ligaments.—These are two thick, short, and wide 158 THE ARTICULATIONS. fasciculi, attached by their superior extremities to the lateral imprints of the second phalanx, and by their inferior extremities into the two cavities at the base of the pyramidal eminence of the os pedis. Each ligament is partly covered by the complementary fibro-cartilage of that bone, and appears to form a portion of it. Its anterior border is continuous with the common extensor tendon of the phalanges; its internal face is covered by the synovial membrane, which adheres closely to it. c. Posterior lateral ligaments—These have been already noticed. Each is composed of the lowermost fibres of the lateral ligament of the first interphalangeal articulation ; these fibres, after being attached to the second phalanx, unite into a sensibly elastic fibrous cord, which is chiefly fixed into the extremity and superior border of the navicular bone, where the ligaments join each other, and in this way form a kind of complementary cushion which increases the navicular articular surface. It also sends off a short fasciculus to the retrossal process, and a small band to the internal face of the lateral fibro-cartilage. Partly concealed by the latter and the plantar cushion, this ligament is covered inwardly by the articular synovial membrane. (For full details as to the manner in which the navicular is attached to the pedal bone, the student is referred to the series of papers on the Horse’s Foot, published by me in the ‘ Veterinarian’ for 1870. It is only necessary to refer here to the intimate connection there exists between the lateral and interosseous ligaments, and the stratiform fibro-cartilage covering the pos- terior face of this sesamoid: a connection, or rather unification, which has been strangely overlooked by hippotomists and hippo-pathologists, but which has undoubtedly a most important bearing on the genesis of that very prevalent and formidable malady of the anterior foot of the Horse —navicularthritis.) Synovial membrane.—This descends below the facets which unite the navicular to the pedal bone. It offers, postericrly, a vast cul-de-sac which reaches the posterior face of the second phalanx, and lies against the two navicular sheaths. It also forms another much smaller, by being prolonged between the two lateral ligaments of the same side. This is very often dis- tended, and it is liable to be opened in the operation for diseased cartilages. Movements.—The same as those of the first interphalangeal articulation. In the Sheep are found: 1, An interosseous ligament to unite the navicular bone to the third phalanx; 2, Two anterior lateral ligaments commencing, as already stated, at the first phalanx ; 3, Two lateral posterior ligaments, passing to the posterior face of the second phalanx and the navicular bone (the internal is yellow and elastic); 4, A single, anterior, elastic ligament, attached above to the superior extremity of the second phalanx, and fixed below into the third, between the insertion of the common extensor of the digits and that of the internal anterior lateral ligament; an inferior interdigital ligament, situated between the ungueal phalanges, whose separation from each other it limits. This ligament is composed of parallel fibres, which extend transversely from the one navicular bone to the other, and is covered on its inferior face by the skin of the interdigital space. Its upper face is in contact with an adipose cushion. In the Oa, the external anterior lateral ligament, wide and expanding, is almost entirely covered by the long branch of the proper extensor of the digit, to which it is intimately adherent. The interdigital ligament has a much more complicated character than that of the Sheep. It is formed of fibres intercrossed on the median line, and divided at its extremities into two fasciculi: a superior passes over the perforans tendon, to which it serves as a restraining band, and is fixed tu the outside of the inferior extremity of the first phalanx. after contracting very close adhesions with a strong fibrous web which descends from the posterior metacarpal region, and which will be more fully noticed when describing the muscles; an inferior, shorter than the preceding, attached to the internal extremity of the navicular bone and the internal face of the third phalanx, ARTICULATIONS OF THE POSTERIOR LIMBS. 159 becoming confounded with the perforans tendon, the plantar cushion, and the kera- togenous membrane. In the Pig, for the maintenance of the second interphalangeal articulation. -there are: 1, Two lateral ligaments, carried from the lateral fuces of the second phalanx to the external and internal faces of the third; 2, A third ligament, exactly resembling one of the posterior lateral ligaments of the pedal articulation of the Horse; this ligament descends from the inferior extremity of the first phalanx to the internal extremity of the navicular bone. Its analogue of the inner side appears to be altogether absent; but in the large digits there is an anterior yellow elastic ligament like that of Ruminants. In the Dog, the two last phalanges are united by two lateral ligaments, very simply arranged. A third ligament, formed of elastic tissue, divided into two lateral portions, and situated in front of the articulation, plays the part of a spring, which mechanically produces the retraction of the claw when the flexor muscles cease to contract. In the Cat, this yellow ligament is very strong; and this animal also exhibits a very striking obliquity of the articular pulleys by which the two phalanges correspond: an arrange- ment which permits the claw to be lodged between two digits when they are raised, and thus favour its retraction. The second interphalangeal articulation of the Dog and Cat is also distinguished by another essential arrangement. ‘The articular surface of the third phalanx is com- pleted by a glenoid fibro-cartilage analogous to that of the first articulation, but much thicker. This fibro-cartilage (see MuscLES OF THE HAND) is fixed into the posterior projection of the third phalanx, and serves, by its inferior face, as a pulley for the per- forans tendon and, with the projection just named, plays the part of the navicular bone in other animals. The interphalangeal articulations of Man are formed on the same plan as the metacarpo-phalangeal articulations. They are consolidated by a glenoid and lateral ligaments, and possess only the two movements of flexion and extension. ArticLe V.—ARTICULATIONS OF THE Posterior Liss. 1. Articulations of the Pelvis, ( Preparation—These ligaments are all exposed to view by carefully removing the soft parts connected with the sacrum and coxe.) A. Sacro-1n1a0 Articunation (Fig. 90).—This is a pair articulation which establishes the union of the posterior limb with the spine, and is formed by the sacrum and coxa. It belongs to the arthrodial class. Articular surfaces—On the sacrum, the irregular diarthrodial facet named the “auricular,” cut on the sides and near the base of the bone. For the coxa, the analogous facet on the internal face of the ilium. Mode of wnion.—By four ligaments, which, after the example of Rigot, we will name sacro-iliac, superior ilio-sacral, inferior ilio-sacral, and the sacro-ischiatic. a. Sacro-iliae ligament.—This is composed of thick ae fasciculi, which envelope the whole articulation in being firmly attachéd by their extremities to the imprints around the diarthrodial facets. The inferior moiety of this ligament is covered by the psoas-iliacus (iliacus) muscle. Its posterior half! is much stronger, is hidden by the ilium, and gives attach- ment to the ilio-spinalis (longissimus dorsi) muscle. . ; b. Superior ilio-sacral ligament.—A thick and short funicle which, rising from the internal angle of the ilium, is carried backwards to be fixed to the sacral spine, where its fibres are confounded with those of the super- spinous dorso-lumbar ligament. c. Inferior ilio-sacral ligament.—This is a very resisting, triangular, membranous band, formed of parallel fibres passing obliquely downwards and backwards. It is attached, by its anterior margin, to the upper half of " It represents the interosseous sacro-iliac ligament of Man, The inferior half corre- sponds to the anterior sacro-iliac ligament. 160 THE ARTICCLATIONS. the ischiatic border and the internal angle of the ilium, in becoming confounded with the preceding ligament. Its inferior margin 1s inserted into the rugged lip which borders the sacrum laterally. Its posterior border is united to the aponeurosis covering the coccygeal muscles, and its external face is in contact with the principal gluteal and the long vastus muscles ; while the internal corresponds to the lateral sacro-coccygeal muscle. d. Sacro-sciatie or ischiatic ligament (Fig. 90, 2).—This is a vast mem- branous expansion situated on the side of the pelvis, between the sacrum and the coxa, and serves more as a means for inclosing this portion of the pelvic cavity than to assure the solidity of the sacro-iliac articulation. ; Its form is irregularly quadrilateral, and permits its circumference to be divided into four borders: a superior, attached to the rugged lateral ridge of the sacrum ; an inferior, fixed to the supercotyloid ridge, as well as the ischial tuberosity, and forming by the portion comprised between these two in- sertions, with the small ischiatie notch, the opening by which the internal obturator and pyramidal muscles leave the pelvis; an anterior, imperfectly limited, along with the great ischiatic notch, circumscribes the opening through which the gluteal vessels and nerves, and the sciatic nerves pass; a posterior, doubled in the form of two lamine which embrace the semi- membranosus muscle, and is confounded superiorly with the aponeurosis enveloping the coccygeal muscles. The external face of this ligament is traversed by the sciatic nerves, and is covered by the long vastus and the semitendinosus muscles, which derive numerous insertions from it. Its internal face is covered, in front, by the peritoneum, and posteriorly is in contact with the ischio-coccygeal and ischio-anal muscles, to which it gives attachment. Synovial membrane.—This lines the sacro-iliac ligament, but only furnishes a small quantity of synovia. Movements.—The two sacro-iliac articulations being the centres towards which all the impulsive efforts communicated to the trunk by the posterior limbs converge, they do not offer much mobility, as that would oppose the integral transmission of the quantity of movement. So that they permit only a very restricted gliding of the articular surfaces; and the union of the sacrum and coxa by diarthrosis appears to be exclusively designed to prevent the fractures to which these bones would be incessantly exposed if they were fixed together in a more intimate manner. B. ArvicuLation or tHE Two Cox, or Iscuto-pusic Sympuysts.—The two coxe are united to each other throughout the whole extent of the inner border of the pubis and the ischial bones. In youth, this is a veritable amphiarthrosis, fixed by an interosseous cartilage and bundles of peripheral fibres. The cartilage is solidly fixed to the small rugged eminences which cover the adjacent articular surfaces, and becomes ossified, like the sutural cartilages, as the animal advances in age. In adult Solipeds the coxe are always fused with each other. The peripheral fibrous fasciculi extend tranversely from one bone to the other, above and below the symphysis; those on the inferior face are incomparably stronger and more abundant than the others. The movements of this articulation are most restricted, and depend solely upon the elasticity of the interosseous cartilage. They cease after its ossification. The fusion of the two cox proceeds very slowly in the female of the Cat, Dog, Pig, Ox, Sheep, and Goat species. ARTICULATIONS OF THE POSTERIOR LIMBS. 161 2. Coxo-femoral Articulation. _ (Preparation — Remove the muselcs surrounding the articulation. To view the interior, divide the capsular ligament by a circular incision.) This is an enarthrosis, formed by the reception of the head of the femur into the cotyloid cavity of the coxa. Articular surfaces—As already shown, the cotyloid cavity represents the segment of a hollow sphere, deeply notched on the inner side, and SACRO-ILIAC AND COXO-FEMORAL ARTICULATIONS, WITH THE SMALL DEEP MUSCLES SURROUNDING THE LATTER. 1, Sacro-iliac ligament; 2, Sacro-ischiatic ligament; 3, Great ischiatic notch; 4, Anterior portion of the capsular ligament of the coxo-femoral articulation; 5, Internal band of cotyloid ligament; 6, Coxo-femoral ligament; 7, Pubio-femoral ligament; 8, Its insertion into the femur; 9, Small gluteal muscle; 10, Origin of the straight anterior muscle of the thigh (rectus); 11, Anterior thin muscle (rectus parvus); 12, Pyramidal muscle of the pelvis; 13, External obturator muscle; 14, Square crural muscle (quadratus femoris); 15, Inferior sacro- coccygeal muscle. provided at the bottom with a wide depression, the internal moiety of which is destined for the insertion of one of the interosseous ligaments, while the external half plays the part of a synovial fossa. This depression is not covered by cartilage, and communicates by the internal notch with the inferior furrow on the pubis. The lip of the cotyloid cavity is covered by a complementary fibro-cartilage—the cotyloid ligament. This fibro-cartilage is not interrupted at the notch just mentioned, but passes over it, forming a remarkable band (Fig. 90, 5) that converts it into a foramen, through which pass the pubio- or ilio-femoral ligament and the vessels of the articulation. 162 THE ARTICULATIONS. Fixed by its adherent border to the margin of the cotyloid cavity, this ligament is lined by synovial membrane on its faces and free border. It is thickest in front and within. Pane sake, With regard to the head of the femur, it will be remembered that it is exactly moulded to the cavity, and, like it, is excavated by a rugged fossa which is entirely occupied by the insertion of the interarticular ligaments. Mode of union.—This jomt is maintained by a peripheral capsule, and by two interarticular bands constituting the coxo-femoral and pubio-femoral ligaments. es . a. Capsular ligament (Fig 90, 4).—This is a membranous sac, like that of the scapulo-humeral articulation, embracing the head of the femur by its inferior opening, and attached by its opposite aperture to the margin of the cotyloid cavity and its protecting fibro-cartilage. This ligament is com- posed of intercrossed fibres, and is strengthened in front by an oblique fasciculus which descends to the body of the femur, along with the anterior thin muscle, near which it is fixed. Its internal face is covered by the articular synovial membrane, and its external face is in contact, through the medium of adipose cushions, with: in front, the anterior thin muscle (crureus) and the straight muscle (rectus) of the thigh ; behind, to the gemini, the internal obturator, and the pyramidal muscles; outwards and upwards, to the small gluteal muscle; within and below, to the external obturator. b. Coxo-femoral ligament (ligamentum teres, Fig. 90, 6).—A thick and short funicle of a triangular shape, deeply situated between the two bony surfaces, which it cannot, notwithstanding its shortness, maintain exactly in contact without the other muscular or ligamentous structures enveloping the articulation. Its upper insertion occupies the internal moiety of the bottom of the cotyloid cavity; and its inferior extremity is confounded with the pubio-femoral ligament, being fixed with it into the rough fossa in the head of the femur. It is enveloped by the synovial membrane. ¢. Pubio-femoral ligament (Fig. 90, 7, 8).—This ligament, longer and stronger than the last, originates from the pubic tendon of the abdominal muscles and the anterior border of the pubis. Lodged in the inferior channel of that bone, it passes outwards, enters the internal notch of the cotyloid cavity, is inflected downwards on the fibrous band which converts that notch into a foramen, and goes with the preceding ligament to be inserted into the fossa in the head of the femur. Its pubic portion lies between the two branches of the pectineus, while its interarticular surface is covered by synovial membrane. Synovial membrane—This membrane is very extensive; it lines the internal face of the capsular and cotyloid ligaments, and is reflected on the interarticular ligaments to form around them a serous vaginal covering. It is even prolonged into the synovial fossa occupying the centre of the cotyloid cavity. Movements.—The coxo-femoral articulation is one of the joints which is endowed with the most varied and extensive movements. It permits the Jlexion, extension, abduction, adduction, circumduction, and rotation of the thigh on the pelvis. The mechanism of these movements is so simple, that they need no particular consideration. The domesticated animals other than Solipeds, are distinguished by the complete absence of the pubio-femoral ligament; so that in them the movements of abduction, which are limited in Solipeds by tlre tension of this ligament, are much more extensive; and it is the absence of the ligament in question, which explains the facility with which the larger Ruminants are enabled to strike sideways, a movement known as a “cow’s kick,” ARTICULATIONS OF THE POSTERIOR LIMBS. 163 In Man, the head of the femur is more detached than in the domesticated animals, and the cotyloid cavity, encircled by the cotyloid ligament, is deeper. The femur is united to the coxa: 1, By a capsular ligament; 2, By a triaugular ligament, fixed above, to the cotyloid ligament at the notch, and below, into the depression in the head of the femur. Also, as the brothers Weber have shown, the atmospheric pressure is a powerful adjunct to these means of union. _ The coxo-femoral articulation of Man permits more extensive movements than that of animals, and especially abduction and adduction, which can be carried to 90 degrees. 3. Femoro-tibial Articulation) (Preparation.—Remove the soft parts surrounding the articulation, taking care not to wound the synovial membrane. To expose the crucial ligaments, make an antero- posterior vertical section of the femur in such a way as to separate the condyles.) This is the most complicated joint in the body, and is formed by the union of the femur with two of the thigh bones—the tibia and patella. It represents an imperfect hinge-joint. Articular surfaces.—To form this articulation, the femur opposes its two condyles to the wide, convex, and undulated facets on the superior face of the lateral tuberosities of the tibia, and its articular pulley to the posterior face of the patella. _ The femoral faces have already been described in detail at page 98; but it may be repeated that the two condyles, placed side by side, are elongated in an antero-posterior direction, and are separated by a non-articular notch called the intercondyloid ; also, that the femoral trochlea situated in front of these two condyles appears to continue the preceding notch, and that its internal border is much more elevated than the external; an arrangement which explains why it is so difficult, if not impossible, for the patella to be dislocated inwards. The tibial facets ascend on each side to the lateral faces of the tibial spine. They are separated from one another by the antero-posterior groove cut on the summit of that bone, and by the fosse of insertion situated at its base before and behind. The external facet, wider than the internal, is devoted in part to the gliding of the originating tendon of the popliteal muscle. (See page 100.) The patellar surface, moulded on the femoral pulley, fits it in an imper- fect manner. It is bordered, outwardly, by a small fibro-cartilaginous ring, which is united to the fibrous capsule of the femoro-patellar articulation (Fig. 92,1). Inwardly, it is completed by the insertion of the internal patellar ligament, to be noticed immediately. ; Interarticular menisci (semilunar Jfibro-cartilages)— (Figs. 91, No. 1, 2, 3, 4; and 92, 5, 6,7, 8)—By this designation is known the, two fibro- cartilages interposed between the condyles of the femur and the tibial facets, to assure their coaptation. They are crescent shaped bodies, and present : an internal, concave, thin and_sharp border, embracing the tibial spine; an external, thick, and convex border ; a superior face, excavated and moulded to one of the condyles; an inferior face, nearly plane, gliding on the tibia; and two extremities terminated by ligaments, and fixed to the bones in apposition. The articular surfaces are not entirely separated throughout their extent by 1 this name is understood the joint uniting the femur to the tibia, and that which eae it ih the patella. Following the example of anthropotomists, it has not been deemed necessary to describe a femoro-patellar articulation distinct from the femoro-tibial, properly so called. This innovation appears to be justified by the com- - munity of the principal articular bands which bind these two joints, and by the reciprocal dependence of their movements, 164 THE ARTICULATIONS. these complementary meniscii, for the tibial spine rubs directly against the inner sides of the femoral condyles. The.internal semilunar fibro-cartilage, the widest and thickest, is inserted by its anterior extremity into one of the excavations situated in front of the spine; its posterior extremity is attached in the fossa behind that eminence. The eaternal semilunar Jibro-cartilage is fixed, in front, near the anterior insertion of the opposite fibro-cartilage ; its posterior extremity gives origin to two slips or cords, one superior, the other inferior. The first, the strongest and longest, terminates in the fossa near the posterior extremity of the intercondyloid notch. The second, thin and flat, is inserted on the posterior outline of the external tibial facet, Fig. 91. No. 2. FEMORO-TIBIAL ARTICULATION. No. 1. Posterior face; the posterior ligament has been removed.—1, External menis- cus; 2, Fibrous tasciculi fixing it to the femur; 3, Fibrous fascia which attaches it to the posterior contour of the tibial surface; 4, Internal meniscus; 5, Tibial insertion of the posterior crucial ligament; 6, External lateral ligament; 7, _ Internal lateral ligament, No. 2. External face: the external condyle of the femur and the meniscus have been removed to show the crucial ligaments,—1, Anterior crucial ligament ; 2, Posterior ditto ; 3, Fibular insertion of the external lateral ligament; 4, Anterior patellar ligaments.—a, Internal meniscus ; B, Anterior insertion of the external meniscus ; C, Passage for the tendinous cord common to the flexor of the metatarsus and the anterior extensor of the phalanges; p, Anterior and superior tuberosity of the tibia; 5, Tibial crest. The external border of this meniscus is separated from the external lateral ligament by the tendon of the popliteus muscle, and acts, with regard to this tendon, as a pulley. Mode of union.—The bands which bind this complicated articulation are very numerous. They will be successively described as: 1, Those which attach the patella to the tibia ; 2, Those which unite the femur with the tibia. A. Ligaments attaching the patella to the tébia.—The patella is bound to the tibia by three funicular ligaments, designated by the generic epithet of “patellar.” They are situated in front of the articulation, and are charged ARTICULATIONS OF THE POSTERIOR LIMBS. 165 with the duty of transmitting to the leg the action of the muscles which are attached to the patella. They are distinguished according to their position as external, internal, and middle. (Fig, 92, 2, 3, 4.) ; _ a The external patellar ligament, the largest and most powerful, is a flattened band, attached, by its lower extremity, to the culminating point of the anterior tuberosity of the tibia. Its upper extremity is fixed to the anterior face of the patella, and is confounded with the patellar insertion of the long vastus muscle. It is joined to the internal ligament by a very resisting aponeurotic expansion, a dependency of the fascia lata. b. The internal patellar ligament also furms a flattened band, longer, but not so wide or thick as the preceding. Its inferior extremity is attached to the inner side of the anterior tuberosity of the tibia. Its superior extremity becomes much thickened and fibro-cartilaginous, and is inserted into a prominence inside the patella. This fibro-cartilaginous portion (Fig. 92, 3’) of the ligament glides on the internal border of the femoral trochlea, and may justly be considered as a complementary apparatus of the patellar surface. The ligament, joined to the preceding by the fibrous fascia already mentioned, is mixed up, inwardly, with the aponeurosis of the adductor muscles of the leg. e. The middle patellar ligament is a round cord, situated, as its name indicates, between the other two, concealed beneath the aponeurosis which unites these, and in the middle of the adipose tissue protecting the synovial capsules in front. It leaves the anterior face of the patella, and descends vertically to the tibia, to be lodged in the fossa in the middle of the anterior tuberosity, where a small synovial bursa facilitates its movements. Tts inferior extremity is inserted into the most declivitous part of this excavation. B. Ligaments which attach the thigh and leg bones.—These are six in number: 1, A femoro-patellar capsule maintaining the patella against the femoral trochlea ; 2, Five femoro-tibial ligaments, as follows: two lateral, faxe-external and internal; a posterior; and two interarticular, distinguished with reference to their inferior insertion into anterior and posterior. a. The femoro-patellar capsule is a membranous expansion which covers, above and laterally, the superior synovial membrane. This capsule is attached by its borders around the femoral trochlea and the periphery of the patellar surface. It is extremely thin in its superior part; but laterally it is thicker, and constitutes two wide fibrous fasciculi which bind the patella to the eccentric sides of the two condyles, and is described in several works as two special ligaments. Its external face is covered by the insertion of the long vastus and the crural triceps. b. The lateral ligaments are two ribbon-shaped cords situated at the extremities of the transversal axis of the articulation, more behind than before ; they are relaxed during flexion, and very tense in extension. The eaternal, the shortest and strongest, proceeds from one of the hollow facets on the external condyle of the femur, and is inserted into the head of the fibula by its inferior extremity, after gliding over the external tuberosity of the tibia by means of a special synovial bursa. It is covered by the crural or tibial aponeurosis, and covers the tendon of the popliteus, from which it is sometimes separated by a vesicular synovial membrane. The internal is attached, superiorly, to the eminence of insertion that surmounts the eccentric face of the internal condyle, and descends vertically to the tibia, gliding over the margin of its articular surface by means of a small facet covered with cartilage, and a cul-de-sac prolongation of the 14 166 THE ARTICULATIONS. internal synovial membrane. It is fixed by its inferior extremity to the imprints which cover the internal tibial tuberosity. : I Its fibres are disposed in two layers, which slightly intercross in X fashion ; those passing downwards and forwards adhere to the border of the internal meniscus. Covered by the aponeurosis of the adductor muscles of the leg, this ligament adheres by its deep face to the internal meniscus. c. The posterior ligament belongs to the class of membranous or capsular ligaments. It is formed of two aponeurotic lamine separated superiorly, but confounded inferiorly. The superficial lamina is composed of strong, fibrous, intercrossed fasciculi, perforated with vascular openings. It is fixed, above, to the posterior face of the femur, below the external gastrocnemius muscle. The deep lamina envelopes, like a cap, the femoral condyles. After becoming united, these two lamine are attached to the posterior face of the tibia, close to the superior articular face of that bone. Its external face is in contact with the pofliteal vessels, and the external gastrocnemius muscle. Its internal face is covered throughout nearly the whole of its extent by the lateral synovial membranes, embraces the condyles of the femur, and adheres to the posterior crucial ligament, as well as to the interarticular meniscil. d. The interosseous ligaments are two funicular bands lodged in the inter- condyloid notch. They are more commonly designated crucial ligaments, because they cross each other at their middle part, like the letter X, Fig. 91. : he an oblique downwards and forwards, is attached by its superior extremity to the bottom of the intercondyloid notch, and inwardly to the external condyle. Its inferior extremity is fixed in the groove on the summit of the tibial spine. The fibres entering into its formation are not parallel, but slightly twisted in a’spiral manner. The posterior, longer than the preceding, and oblique in the opposite direction, is inserted, inferiorly, into the little eminence behind the internal tibial facet ; whence it goes to the bottom of the intercondyloid notch, to be attached by its superior extremity within the internal condyle. Synovial membranes.—For this articulation there are three synovial membranes: a superior and two lateral. The first, very large and sustained by the femoro-patellar capsule, facilitates the gliding of the patella on the femoral pulley; it is prolonged in a cul-de-sac below the insertion of the crural triceps. The other two, which lubricate the articular surfaces of the proper femoro-tibial joint, include the crucial ligaments between them, and cover the posterior hyament, the lateral ligaments, and the fibrous fasciculi for the attachment of the meniscii. The external covers, in addition, the tendon of the popliteus muscle, and furnishes a vast cul-de-sac which descends in the anterior groove of the tibia to envelop the tendon common to the anterior extensor of the phalanges and the flexor of the metatarsus. These two femoro-tibial synovial membranes le against that of the femoro-patellar articulation, in front of the condyles and the notch which separates them, and if not always, at least not unfrequently, they communicate with it. The three are separated from the ligaments of the patella by a considerable mass of adipose tissue which is prolonged into the intercondyloid notch, at the bottom of which it appears to be fixed. Movements.—This imperfect hinge joint can execute the two principal and opposite movements of flewion and extension, and a somewhat limited acces- sory movement of rotation. The mechanism of these movements being simple enough to be readily understood without any preliminary explanation, ARTICULATIONS OF THE POSTERIOR LIMBS. 167 they will not be detailed here; but some remarks will be made with regard to the displacement the fibro-cartilages undergo when the articulation is in motion. During fleaion and extension, these bodies, fixed on the tibial facets, which they transform into glenoid cavities, move with them on the condyles of the femur, from before to behind, or behind to before, according to the movement executed. But at the same time they also glide in an inverse direction, and to a very appreciable degree, on the superior extremity of the tibia. There- fore, during flexion, they pass from behind forward on this extremity, and are drawn backwards during exten- sion. Tn rotation, which may take place from within to without, or from with- out to within, the movement is pro- duced not only by the pivoting of the condyles in their glenoid cavities, but also by a sensible displacement of the meniscii on the tibial surfaces. In the Dog and Cat, the meniscii are joined together near their anterior insertion y a transverse fibrous band. There is only one patellar ligament, and the posterior liga- meut shows in its thickness two small sesa- moid bones against which the condyles of the femur play inwardly, and which give attachment, outwardly, to the originating branches of the external gastrocnemius mus- cle. There isno femoro-patellar capsule, and only one synovial membrane for the whole articulation. In the Pig and Sheep, there is also only one ligament and one synovial capsule. 4, Tibio-fibular Articulation. This articulation represents a small planiform diarthrosis, whose move- ments are very limited and obscure. It is formed by the union of the irre- gular diarthrodial facet which occupies the internal face of the head of the fibula, with the analogous facet on the external superior tuberosity of the tibia. Short and strong interosseous or peripheral fibres envelop these facets on every side, and maintain them firmly in contact. LIGAMENTS ATTACHING THE THREE BONES OF THE LEG, No. 1. Posterior face.—No. 2. Anterior face. —1, Complementary fibro-cartilaginous pad of the patellar surface; 2, External patellar ligament ; 2’, Insertion of the long vastus into this ligament; 3, Internal patellar ligament; 3’, Its upper insertion transformed into a complementary appa- ratus of the patellar surface; 4, Middle patellar ligament, 5, External meniscus of the tibia; 6, Its branch of insertion into the femur cut off at its origin: 7, Its posterior tibial insertion; 8, External me- niscuss 9, Insertion of the anterior crucial ligament into the fossa of the tibial spine; 10, Tibial insertion of the posterior crucial ligament; 11, Inferior insertion of the ex- ternal femoro-tibial ligament; 12, 13, 14, Tibio-fibular ligaments.—a, Tibial arch; 3B, Surface of insertion of the popliteus muscle; C, Surface of insertion for the perforans muscle. The fibula is also attached to the tibia: “1, Above, by two small liga- mentous fasciculi crossed like the letter X, which form the superior part of the great arch through which pass the anterior tibial artery and vein (Fig. 92,12); 2, In the middle, by a kind of aponeurotic membrane, whose width 168 THE ARTICULATIONS. diminishes from above to below, like that of the space it fills (Fig. 92, 13); 8, Below, by a ligamentous cord (Fig. 92, 14) which prolongs the fibula to the external tuberosity of the inferior extremity of the tibia, where this cord bifurcates, and is united to the two external lateral ligaments of the tibio- tarsal articulation.” —Rigot. In the Or, Sheep, and Goat, the fibula being replaced by a ligament, there is no proper tibio-fibular articulation. ‘ In the Dog and Cat, the two principal bones of the leg are united at their extremities and middle part: 1. At their superior extremity, by means of a small arthrodial articulation, analogous to that of the Horse, and, like it, provided with a particular synovial bursa ; 2. At their inferior extremity, by means of a second arthrodial articulation, whose action is facilitated by a prolongation of the tibio-tarsal synovial membrane ; 3. By their middle part, through the interposition, between the two bones, of an interosseous ligament, which is wide and membranous in its upper two-thirds, and formed of extremely short and strong fibres at its lower third. In the Pig, the arrangement is somewhat the same as in Carnivora. It may be noted, however, that the facet of the upper extremity of the fibula is joined to the tibia by a small interosseous ligament, and that the articulation which results should be looked upon as a small amphiarthrosis. In Man, as in the Dog there are two peroneo-tibial arthrodiz : a superior and inferior. 5. Articulations of the Tarsus or Hock, (Preparation—Remoye the tendons from around the articulation, and incise, layer after layer, the superficial fibres of the lateral ligaments.) These comprise: 1, The tibio-tarsal articulation; 2, The articulation of the first row of bones—the astragalus and calcis ; 3, Those which unite the bones of the lower row; 4, The articulation of the two rows with each other ; 5, The tarso-metatarsal articulation. The first is a perfect gingly- moid, and the only joint really movable; all the others are arthrodial, and their action is so restricted that they appear to be condemned to almost absolute immobility. This intimate union of the tarsal and metatarsal bones is evidently chiefly intended to guarantee precision in the movements of the tibio-tarsal articulation. Trp10-rarsaL ARTICULATION.—T wo bones alone concur in the formation of this angular ginglymoid joint : these are the tibia and astragalus. Articular surfaces—For the tibia: 1, The two deep grooves, oblique forwards and outwards, channeled in the inferior extremity of the bone; 2, The salient tenon which separates these grooves, and on which there is often a small synovial fossctte.—For the astragalus, the pulley occupying its anterior face (see page 103). Mode of union.—Seven ligaments bind these articulations: two external lateral, three internal lateral, an anterior and a posterior. a. External lateral ligaments.—These are distinguished, according to their relative position, into superficial and deep. The external superficial ligament (Figs. 98, 2; 94, 2), is a thick funicular cord, flattened in its inferior half. It commences above on the external tuberosity of the tibia, behind the groove which divides this tube- rosity into two parts; from thence it descends almost vertically, fixing itself successively to the astragalus, calcaneus, cuboides, middle metatarsal bone, and the external rudimentary metatarsal bone. Passing in front with, and partly covered by, the lateral extensor of the phalanges, to which it supplies a retaining band (Fig. 94, 2), this ligament is confounded behind, and near its inferior extremity, with the calcaneo-metatarsal ligament. It ARTICULATIONS OF THE POSTERIOR LIMRS. 169 covers the external and deep ligament, the short band which constitutes the external calcanco-astragaloid ligament, the insertion of one of the branches of the flexor of the metatarsus, and the small cuboido-cunean ligament. (cuneiform) The external deep ligament (Figs. 93; 94, 1), much shorter than the preceding, is attached, superiorly, to the anterior part of the external tuberosity of the tibia, and is directed obliquely backwards and downwards, to be fixed by two fasciculi at the external side of the astragalus and calcis. This ligament, covered by the preceding, which crosses it like an X, is lined on its inner face by the synovial membrane of the articulation. b. Internal lateral ligaments.—These are algo three funicular bands superposed on one another, and are oy designated as superficial, middle, and eep. The internal superficial ligament (Fig. 98, 6), the strongest and longest of the three, proceeds trom the internal and inferior tuberosity of the tibia, diminishing as it descends on the inner side of the tarsus. It is fixed, in mixing with the astragalo- metatarsal ligament and with the posterior tarso- metatarsal ligamentous arrangement, to the tuberosity of the astragalus, the scaphoid, the two cuneiform, the superior extremity of the principal metatarsal, and that of the internal rudimentary metatarsal bones. The internal middle ligament (Fig. 93, 5) is com- posed of two funicular cords, attached in common beneath the preceding ligament to the internal tibial tuberosity. These two fasciculi, exactly resembling those of the external deep ligament, are directed downward and backward, and terminate, one at the astragalus, the other at the calcis. The internal deep ligament (Fig. 93, 4) is an ex- tremely slender fasciculus, enveloped by the synovial membrane; it is often reduced to a thin shred, scarcely distinct from the serous covering surround- ing it. It is attached, in one direction, to the tibia below the middle ligament; in the other to the astragalus, and nearly at the same point as the superior fasciculus of the middle ligament. Fig. 93. TARSAL ARTICULATIONS; RONT VIEW. 1, External deep ligament of the tibio-tarsal ar- ticulation; 2, 2, Ex- ternal superficial liga- ment; 4, Internal deep ligament; 5, Internal middle ligament; 6, In- ternal superficial liga- ment; 7, Astragalo- metatarsal ligament; 8, Small cuboido-cunean ligament.—a, Pulley of the astragalus; B, Cu- boidal insertion belong- ing tothe tendinous cord of the flexor of the me- tatarsus; ©, Vascular canal of the tarsus. ce. Anterior ligament.—This is a membraniform band formed of inter- crossed fibres, stronger outwards than inwards, attached by its upper border above and in front of the tibial surface, fixed by its inferior border to the astragalus, the scaphoid and great cuneiform bones, and the astragalo- metatarsal ligament; it is confounded at its sides with the two superficial lateral ligaments. Its internal face is lined by articular synovial mem- brane, while the external is covered by the flexor of the metatarsus, the anterior extensor of the phalanges, the anterior tibial artery, and several large anastomosing veins from whose junction arises the anterior tibial vein. d. Posterior ligament.—This is the second membraniform or capsular band which protects the articulation posteriorly, It presents, in its centre, 170 THE ARTICULATIONS. a fibro-cartilaginous thickening, on which glides the perforans tendon. Tt is attached, above, to the tibia, below, to the astragalus and calcis; at its sides it is mixed with the two superficial lateral ligaments, and the astragalian fasciculus of the middle internal ligament. Its internal face is lined b articular synovial membrane; the external is covered and lubricated by the vaginal serous membrane which facilitates the gliding of the perforans tendon in the tarsal sheath. Synovial membrane.— This membrane is developed at the internal face of the two capsular ligaments, nearly covers the three internal ligaments, and lines the external deep ligament. It communicates, in front and below, with the synovial membrane proper to the articulation of the two rows of tarsal bones. When it becomes the seat of dropsical effusion, it is always distended forwards and inwards, because it is only sustained at that place by the anterior capsular ligament. But the effusion may also raise the posterior ligament and produce hernia in the hollow of the hock, behind the lateral ligaments. It is not, therefore, absolutely correct to attribute all the synovial tumours in the hollow of the hock to dilatation of the tarsal tendinous sheath. Movements.—Nothing can be less complicated than the mechanism of the tibio-tarsal articulation ; this joint only permitting two opposite movements, those of flewion and extension, which are so simple and precise that we may dispense with a description of the manner in which they are executed. It may only be remarked that, in order to prevent contact between the leg and foot during flexion, the latter fraction of the limb deviates a little outwards, owing to the marked obliquity of the articular grooves. ARTICULATION OF THE Bones oF THE First Row, orn CAatoanzo- ASTRAGALOID ARTICULATION.—This is a compound arthrodial joint, resulting from the coaptation of the three or four articular facets of the posterior face of the astragalus with the analogous facets of the calcis, This joint is maintained by the lateral ligaments of the tibio-tarsal articulation, and by four calcaneo-astragaloid ligaments—a superior, external, internal, and the last interosseous. The superior calcanco-astragaloid ligament is formed of short parallel fibres thrown across from one bone to the other, and is situated towards the superior extremity of the pulley of the astragalus; it is lined superiorly by the synovial membrane of the tibio-tarsal articulation. The lateral ligaments are two very thin fasciculi concealed by the ligaments which bind, laterally, the tibia to the tarsal bone. The interosseous ligament is very strong, and occupies a great portion of the rugged excavation which separates the articular facets. This articulation does not usually possess proper synovial capsules. Two prolongations of the synovial membrane of the two rows, in ascending between the calcis and astragalus, facilitate the gliding of the two inferior facets. An analogous prolongation of the tibio-tarsal synovial membrane is effected for the superior facets, and it is not rare to find this prolongation form a distinct capsule. Movements nearly null ARTICULATION OF THE Bonus oF THE SxconD Row wIta EACH OTHER.— These bones, four in number, are brought into contact in the following manner :—The cuboides responds to the scaphoid by two facets, one anterior, the other posterior ; it articulates with the great cuneiform by two similar facets, the posterior of which is not always present. The scaphoid is united to the two cuneiforms by the large convex facet occupying its entire lower ARTICULATIONS OF THE POSTERIOR LIMBS. 71 face. surface. The two cuneiforms are joined by means of a small articular The fibrous fasciculi which maintain the diarthrodial surfaces in contact are somewhat numerous. They are as follows: 1. The astragalo-metatarsal ligament and tarso-metatarsal apparatus, which will be described hereafter ; these two bands do not properly belong to the articulations of the second row of bones. _2. Two anterior ligaments, named cuboido-scaphoid and cuboido-cunean (Figs. 93, 8; 94,5), which are carried from the cuboid to the scaphoid and to the great cuneiform bone, one above, the other below the vascular channel formed between these three bones. 3. Two interosseous ligaments analogous to the preceding two, forming the superior and inferior walls of the aforesaid channel. 4, An interosseous scaphoido-cunean liga- ment, passing from the scaphoid to the two cuneiform bones. 5. An interosseous ligament, named the intercunean, is directed from one cuneiform bone to the other, and is confounded with the . preceding ligament. The disposition of the lubricating mem- branes varies with that of the articular facets. The following is what is most generally observed :—A proper synovial membrane is specially destined for the facets by which the scaphoid and great cuneiform bones correspond ; this synovial membrane belongs also to the two cuboido-scaphoid and posterior cuboido-cunean artkrodie. The anterior cuboido-scaphoid diar- throsis receives a prolongation from the syno- vial membrane of the two rows. The play of the anterior cuboido-cunean and intercunean facets is facilitated by two prolongations of the tarso-metatarsal synovial membrane. Movements almost null. ARTICULATION OF THE Two Rows WITH EACH oTHER.—This arthrodial joint is formed by the union of the calcis and the astragalus, on the one side, with the scaphoid and cuboid bones on the other. Its solidity is assured by six principal bands: 1. The two lateral superficial ligaments of the tibio-tarsal articulation. . 2. The calcaneo-metatarsal ligament (Fig. 94, 3), a strong fibrous brace which unites the ARTICULATIONS OF THE TARSUS$ LATERAL VIEW. 1, External deep ligament; 2, External superficial ligament ; 2', Ring furnished by the latter ligament for the passage of the lateral extensor tendon of the phalanges; 3, Calcaneo-meta- tarsal ligament; 4, Astragalo- metatarsal ligament; 5, Small cuboido-cunean ligament.—a, Cuboidal insertion of the flexor muscle of the metatarsus; B, Anterior orifice of the vascular conduit of the tarsus; Cc, Groove on the external tuberosity of the tibia for the gliding of the lateral extensor of the pha- langes; D, Insertion of the gas- trocnemius tendon of the leg into the os calcis; E, Gliding surface for that tendon, posterior border of the calcis to the cuboides, and to the head of the external rudimentary metatarsal bone. It is confounded, outwardly, with the external and superficial tibio-tarsal ligament; inwardly, with the posterior tarso- metatarsal band. 3. The astragalo-metatarsal ligament (Fig. 98, 7), a radiating fasciculus whose fibres leave the internal tuberosity of the astragalus, become mixed 172 THE ARTICULATIONS. up with the internal and superficial tibio-tarsal ligaments in diverging down- wards to the scaphoides, the great cuneiform bone, and the upper extremity of the principal metatarsal bone. ; 4. The posterior tarso-metatarsal ligament is a vast, very strong, and very complicated fibrous arrangement, which binds, posteriorly, all the tarsal bones, and also fixes them to the three portions of the metatarsus. This band, which is crossed by several tendons and by the artery and vein lodged in the cuboido-scaphoido-cunean canal, is continued below by the tarsal stay of the perforans tendon. It therefore closely resembles the posterior carpal ligament. Its posterior face is covered by the tendinous synovial membrane lining the tarsal sheath for the passage of the perforans tendons. It is confounded, on its sides, with the calcaneo-metutarsal, and the internal and superficial tibio-tarsal ligaments. 5. An interosseous ligament, attached to the four bones composing this articulation. It is provided with a particular synovial membrane which always communicates, in front, with the tibio-tarsal capsule. This membrane is prolonged, superiorly, between the calcis and astragalus, to lubrify two of the facets by which these bones come into contact; and, in addition, it descends between the cuboid and scaphoid bones to form a third pro- longation for the anterior cuboido-scaphoid arthrodia. Movements almost null. TaRsO-METATARSAL ARTICULATION.—This joint, formed by the meeting of the three tarsal bones—the cuboid and the two cuneiforms—with the three bones of the metatarsus, is fixed by the lateral superficial ligaments of the tibio-tarsal articulation, the calcaneo-metatarsal ligament, those which have been named the astragalo-metatarsal and tarso-metatarsal, and by a strong interosseous ligament which naturally forms three fasciculi. The synovial membrane proper to this joint ascends into the small anterior cuboido-cunean arthrodia, and into that which unites the two cuneiform bones; it descends to the intermetatarsal articulations. Movements nearly null. Tn all the domesticated animals except Solipeds, the tarsal articulations offer some diffe- rential peculiarities whose study is without interest, as it is without utility. It is only necessary to remark that the immobility of the tarsal joints, properly called, is less absolute than in Solipeds, owing to the peculiar configuration of the articular surfaces of some of the bones composing them. ‘T’hus, in the Ox, Sheep, Goat, and Pig, the calcis is joined to the astragalus by a real trochlear articulation, and the latter bone is united to the seaphoid by a diarthrodial joint of the same kind; a mode of articulation much more favourable to motion than that of the planiform diarthrodial joint. In the Dog and Cat, the same result is obtained by the reception of the head of the astragalus into the superior cavity of\the scaphoids. In Ruminants and the Pig, it is also observed that the tibio-tarsal articulation is re o the tibia and fibula in the one direction, and by the astragalus and os calcis 1n e other, * CHAPTER III. OF THE ARTICULATIONS IN BIRDS. Tue study of the articulations in birds will only arrest us for a few moments, as it will be confined to some remarks on the intervertebral occipito-atloid and temporo- maxillary joints, the only ones exhibiting a special conformation worthy of attention. Intervertebral articulations —The great mobility of the neck of birds is not only due to the fact of its length, relatively considered, but also to the peculiar manner in which the vertebre of this portion of the spinal stalk are articulated. It will be remarked that ARTICULATIONS IN BIRDS. 173 these do not unite by their bodies in the form of a continuous series of amphiarthroses as in the domesticated mammals; but that instead of these mixed articulations there are veritable diarthroses, which may be included in the class created by Cruveilhier under the title of articulation by reciprocal ball and socket, each vertebra becoming counected with the adjacent vertebrae by means of facets convex in one sense and concave in the sense perpendicular to the first. These facets are manifestly covered by curtilage of incrustation ; and it appears that, instead of their being applied directly against the opposite facets, which present a precisely inverse conformation, they are separated by an extremely thin fibro-curtilaginous disc, which resembles the interosseous meniscus of the temporo-maxillary articulation in the Carnivora of the Cat specics. Two loose synovial capsules, separated by this interarticular lamina, complete the framework of each articulation, and favour the play of the vertebrae on one another. This arrange- ment has only, so far as we are aware, been observed in the swan, and that very imperfectly; but it probably belongs tu the entire class of birds, for until now we have met with it in all the individuals submitted to examination. In its dorso-lumbar and sacral portion, the spine is w single piece, in consequence of the consolidation of the vertebree, und does not show any proper articulations. In the coccygeal region, the mobility of the spine re-appears; but it is far from being so marked as in the cervical region ; the vertebrae here are united by amphiarthrosis, and not by reciprocal ball and socket. Occipito-atloid articulation.—It has been shown that there is only one more or less spheroidal condyle of the occipital bone, and a single cavity on the anterior margin of the spinal canal of the atlas. The occipito-atloid articulation is therefore a true enar- throsis, with varied and very extensive movements; w disposition which accounts for the facility with which birds can pivot their heads on the superior extremity of the vertebral stalk. Lemporo-maxillary articulation.—The play of this articulation offers one peculiarity in that it causes, during the separation of the mandibles, not only the depression of the inferior, but also the elevation of the superior mandible. The arrangement which permits this movement hus been already made known; but yet it is ditticult to understand, be- cause there is no active agent, no proper muscle to directly effect it. Nevertheless, the mechanism which executes it is most simple, and may be given in a few words: Tlius, we know that the square bone, interposed between the temporal and maxillary bones, like the interarticular meniscus of mammals, is united outwardly with the jugal bone, and inwardly with the pterygoid. We know also that the latter rests, by means of a diarthrodial tacet, on the body of the sphenoid, and that it abuts against the posterior extremity of the palate bones; while the first, the zygomaticus, is joined directly to the supermaxiJlary bone. The superior jaw, it is also known, is movable on the cranium, because of the flexibility of the cartilages or bony plates uniting these two portions of the head. It may then be added, that the square bone receives on its auterior process one or two small muscles which are attached to the base of the cranium, and that these bones may be pushed, or rather drawn forward, by tle contraction of these muscular fasciculi. It is this projecting, or pushing, transmitted to tle upper mandible through the medium of the jugal bone on the one side, and the pterygoid bone on the other, that produces the elevation of that mandible. Nothing is easier than to prove it; it is only necessary to take the head of a bird, denude it of all its soft parts, and press with the fingers behind the two square bones, to imitate the action of the elevator muscles; we then see the internal extremity of the pterygoid bone glide on the facet of the sphenoid, and push before it the palatine bone, during which the zygomatic bone acts in the same manner on the maxillary; and in this way is produced, through the influence of this postero-anterior propulsion, the ascending movement we undertook to explain, THIRD SECTION. Tue MuscLEs. Arver the study of the bony levers and their articulations, comes the description of the agents whose function it is to move them. These are the muscles, fibrous organs possessing the property of contracting under the influence of a stimulus. 174 THE MUSCLES. They are distinguished as striated (or striped) and non-striated (or unstriped) muscles, according to the character of the anatomical element composing them. ’ The non-striated (or unstriped) muscles are removed from the influence of the will, and belong to the organs of vegetative life. They are also designated as internal muscles, or muscles of organic life. The striated (or striped) muscles, differ from the first in that, with the exception of the fleshy tissue of the heart, their contractile power is immediately placed under the influence of the will, They are more particularly concerned in the execution of the functions of relation, which causes them to be named the external muscles, or muscles of animal life. These muscles are nearly all attached to the skeleton, and represent the active agents in the movements of the osseous framework; they will, therefore, be the only ones referred to in this place, in studying the locomotory apparatus. But before entering upon the particular description of each muscle, we will allude to the general considerations relative to their history. CHAPTER I. GENERAL CONSIDERATIONS ON THE STRIATED MUSCLES, THE STRIATED MUSCLES IN GENERAL. In this first paragraph, we will survey in a general manner the volume, situation, form, direction, attachments, relations, and names of the muscles belonging to the locomotory apparatus. A. Votumn.—Nothing is more variable than the respective volume of the external muscles. What a difference there is, for example, between the small scapulo-humeral muscle and the long vastus or ilio-spinalis (longissimus dorsi)! and what a number of intermediate sizes between these three points of comparison! There are consequently very great, great, medium, small, and very small muscles. The weight of the total mass of these organs varies according to the. species, age, sex, and state of health; but taking a general average, it will be found that it represents nearly one-half the entire weight of the body. B. Srrvation.—There is no need to insist upon the fact, that a knowledge of the situation of the muscles is one of the first objects to be acquired with regard to their disposition. They may, like the bones, be described in two ways. 1. In relation to the median plane of the body, from whence their division into pairs and single muscles. The last, very few in number, are far from exhibiting the symmetry which exists in the bones of this division, as may be seen in the diaphragm, 2. In relation to the other organs, such as the bones and surrounding muscles. C. Form.—With regard to their absolute form, the muscles, again, like the bones, are classed as long, wide, and short. Long muscles.—These muscles are more particularly met with in the limbs. Provided with a principal axis, to which we may ascribe the effect of their contraction, they present a middle portion—usually protuberant, and GENERAL CONSIDERATIONS ON THE STRIPED MUSCLES. 175 two extremities of unequal thickness; the most voluminous, always turned upwards, is metaphorically designated the head, the other the tail. They are most frequently fusiform, sometimes conical, but rarely cylindrical, prismatic or flattened into thin bands, “There is a particular kind of long muscles which have no analogy with those of the extremities, except in their external appearance. They are those which lie below, but more particularly above, the spine. Although at the first glance they appear simple, yet they present as many distinct fasciculi as there are vertebre. The transverse spinous (spinalis dorsi), etc., is no doubt an elongated fasciculus like the sartorious, etc., but the structure of this fasciculus has nothing in common with that of the latter muscle : it is a series of small fasciculi which have each their distinct origin and termination, and only appear as a single muscle because they are in juxta- position.” —Bichat, ‘ Anatomie Générale.’ Wide muscles—Wide muscles are those which have two principal axes, and are stretched beneath the skin, or around the great cavities of the trunk, which they concur in inclosing and separating from one another. They are elliptical, quadrilateral, triangular, trapezoid, etc. Short muscles.—These are found chiefly around the short bones, or at the periphery of the articulations which are deeply buried under enormous muscular masses. Although their name indicates that their three axes offer nearly the same dimensions, yet there is most frequently one, and even two, which predominate. They may therefore be assimilated, in this respect, to the long or wide muscles. D. Drrection.—Cruveilhier has justly remarked, that the direction of a muscle is one of the most important features in its history; for it allows the determination of the angle of incidence of the muscle on its arm of the lever, the power of its action, and the nature of its uses. With regard to the direction of the muscles, we may observe: 1, The form of their principal axis; 2, The relation of this axis to the plumb- line; 3, Its comparison with the axis of the bony levers which the muscles surround or move. a. A muscle is termed rectilinear when its principal axis is straight; it is curvilinear, or circular, if this axis describes a curve more or less marked; it becomes inflected when it proceeds in a certain direction, and afterwards turns on a bony or cartilaginous pulley in another direction : that is to say, when its principal axis is broken into several lines. If the muscle offers two axes, it will be flat or concave, these being one or the other, or straight or curvilinear. : b. With regard to the direction of the muscles to that of the plumb-line, itis either vertical, horizontal, or oblique, expressions which carry their own definition and require no explanation. c. If the direction of the muscles be compared with that of the bony levers they surround and move, it will be found that they are either parallel to these levers, or form with them angles more or less acute. The proper direction of the bones being known, it is sufficient to indicate that of the ‘inuscles to clearly establish this comparison. For instance, in saying that the majority of the muscles of the shoulder are oblique from above to below, and from before to behind, it is understood that these muscles are parallel to the scapula, and that their incidence on the humerus takes place at a right angle. Gre ¢ BE. Arracunents on Insurtions.—This is undoubtedly the most essential part of the study of the muscles; for with the knowledge of their insertions 176 THE MUSCLES. we may determine their extent and direction, and even their relations and uses. By the term attachment, fied insertion, or origin, is meant the point of the muscle which most usually remains fixed while that organ contracts; the attachment, movable insertion, or termination is the name given to that portion which corresponds to the lever displaced by the muscular contraction. Muscles are frequently met with whose two insertions are alternately fixed or movable ; and in such cases care is taken not to give these insertions one or other of the designations. The fixed insertion is often confounded with that of other muscles; the movable insertion is generally free and independent. . The muscles are sometimes directly attached to the bones by the ex- tremities of their fleshy fibres; but most frequently they are fixed to these inert levers through the medium of a tendon or an aponeurosis, whose volume is less considerable than that of the fibres, Without this latter disposition, the surface of the skeleton would not have been sufficiently extensive to give insertion to all the external muscles. The attachment of the muscles to the bony levers is effected by a kind of fusion between the fleshy or tendinous fibres, and the periosteum. F. Revattons.—The indication of the relations of the muscles completes the idea of their situation, and is of great importance in a surgical point of view. They should, therefore, be studied with all the precision possible. The muscles entertain relations either with the skin, the bones, other muscles, or with vessels and nerves. a. It is only, properly speaking, the subcutaneous muscles, such as the panniculus carnosus and the muscles of the face, which are really in im- mediate contact with the skin. The others are separated from it by the aponeurotic fascia which will be described as the appendices of the muscular system. . b. The superficial muscles are only related to the bones by their ex- tremities. Those which are deeply situated are immediately applied by their bodies against the bones of the skeleton. c. The muscles are related to each other in a more or less intimate manner. Sometimes they adhere closely to one another; and at other times they are separated by interstices filled with fat or cellular tissue, and generally traversed by vessels and nerves. d. The connections of the muscles with the latter organs sometimes assume a remarkable character; this is when one of them accompanies, like a satellite, the vascular and nervous trunks concealed beneath its deep facc. There is in this circumstance an important fact with regard to surgical anatomy. G. Nomenciaturr.—Before the time of Sylvius, the muscles had not received particular names. Since the days of Galen they had been dis- tinguished by the numerical epithets of first, second, third, etc., to indicate their place and their order of superposition in the regions to which they, belonged. It is in this fashion that they are designated in the Italian work on the Anatomy of the Horse by Ruini. Sylvius was the first to give Lhe muscles real names; and his example being followed by succeeding rnthropotomists, the nomenclature of these organs was soon completed. But no general view, no methodic spirit guided Sylvius and his successors; it was sometimes their form, and sometimes their direction, position, uses, etc. to which the muscles owed their names. GENERAL CONSIDERATIONS ON THE STRIPED MUSCLES. 177 Bourgelat applied this nomenclature to the horse, but modified it in many points. Chaussier, struck by the imperfections of the nomenclature introduced into science by Sylvius, sought to substitute for it another much more philo- sophical. This anatomist gave to each muscle a name formed by two words indicating the insertions of the organ. Girard imported this ingenious idea into veterinary anatomy. Nevertheless, notwithstanding its advantages, this new nomenclature did not supersede the old one; because it ceased to be correct when applied to comparative anatomy, the same muscles not having the same insertions in all the species.’ It is not, however, that the ancient nomenclature has more advantages in ‘this respect than the new. What can be more improper, for example, than the names of deltoid, splevius, soleus, digastricus, etc.? Do the muscles which receive these desig- nations, considered in mammals only, offer in all species the form or the structure which justifies the employment of these names in the human species? Are the distinctive epithets of great, medium, little, etc., given to many of them, reasonably applicable in every case? May not the same objection be urged against the majority of the names derived from their uses, complications, ete. ? No system of myological nomenclature is really philosophical, and we are of those who believe it to be indispensably necessary to create one; indeed, we are inclined to think that it would be simple and easy to attain this result in starting from a basis whose fixity and invariability should be well defined. And this basis is, in our opinion, already discovered ; it is the principle of connections founded by E. Geoffroy Saint-Hilaire in his immortal ‘ Philosophie Anatomique,’ a principle to which modern science certainly owes its finest conquests. This is a subject which it is our intention to treat in a special work; but we may, nevertheless, indicate here the manner in which it presents itself to us. We are desirous that the myological nomenclature should rest entirely, in the first place, on the relations of the muscles with the pieces of the skeleton, or with other organs equally fixed and very important ; in the second place, on the reciprocal connections of the muscles. Such is our plan; and it is not precisely new, for the old anatomists were often inspired with it, though unwittingly, as the principle on which it is founded was to them entirely unknown; this circumstance, however, immediately leads us to an appre- ciation of its value. For instance, what could be happier tl,an the name of intercostals given to the muscles situated between the ribs. and their distinction into external and internal? Here we have names which indicate the relations of the muscles they desig- nate with the portions of the skeleton and the reciprocal connections of these muscles. It can also be applied in an equally rigcrous manner to every species. We may also cite the supracostals, the intertransverse, the transverse spinous, the subscapularis, the supraspinous, the subspinous, etc., as they are {ound in a greater or less marked degree in identical conditions. Other muscles have received names derived in part from their situation, and in part from their volume. These names are far from being as convenient as the first; as may be judged from the following examples : . In the majority of vertebrate animals, there are three important muscles situated above and behind the pelvis, and forming the basis of the buttock ; they have been designated gluteals, and this name is convenient, because it designates their situation. But to distinguish them from each other, regard has been had to their volume; so that there is a great, a medium, and a small gluteus. This isan error, however, for the volume of the muscles is subject to the greatest variations, and a voluminous muscle in one species may be a very small one in another, and vice versd. The muscle analogous to the «gluteus maximus in Man has been described by Bourgelat as the minimus, and by Lafosse and Rigot as the medius. With regard to tlie glutgus medius of Man, its representative in the lower animals has been designated as the maximus by the majority of veterinary anatomists. What confusion! And how easy it v & to evade it by distinguishing these muscles, not by their volume, but by their reciproeai connections, which are the same in every species! Is it not, indeed, more natural toxusubstitute the names of superficial, middle, and deep gluteals, for those of great, etc ? : : The same remark is applicable to the muscles which, in Man, cover the anterior aspect of the chest. Designated in common, and justly so, as pectorals, these muscles are wrongly distinguished into great and little; for the last, which is already an 178 THE MUSCLES. In this work we will follow the nomenclature of Bourgelat, which will however, be submitted to some change. But as the names given by Girard are, in our opinion, of some assistance to students, care will be taken to include them in the synonymy. ; (It only remains for me to add that Chauveau’s nomenclature will be followed as closely as possible. It possesses advantages which are greatly superior to that adopted by Percivall ; and as, in my opinion, the names and terms imported into science should be as nearly alike in all languages as may be compatible with circumstances, in order to facilitate study, comparison, and reference, I the more readily venture to take this step. Percivall’s nomenclature will, however, be added in brackets to the synonyms, as well as that of Leyh and Gurlt when occasion appears to demand it.) STRUCTURE OF THE STRIPED MUSCLES, There enter into the structure of muscles: 1, Muscular tissue, properly so-called; 2, Conjunctival tissue in the form of delicate lamelle, aponeuroses, or tendons; 3, Vessels and nerves. A. Mouscu.ar Tissvzr.—This tissue is composed of prismatic fasciculi, which it is possible to divide and subdivide into several smaller and smaller fasciculi, until the muscular fibre or primitive fasciculus is rcached. The muscular fibre is a kind of irregular polyhedron, with rounded angles, and extremities terminating in a blunt point. It is sometimes straight, sometimes wrinkled, but always striped either in a longitudinal or transversal direction, or both at once. B, ULTIMATE FIBRIL This fibre is formed by an envelope and contents. OF MUSCLE, accord The envelope is avery delicate, structureless mem- ing to Bowman. : i; Muscular Shremans brane of an clastic nature, named the sarcolemma or highly magmified, its ™”yolemma. Nuclei in greater or less number can be myolemma being so seen on its inner face. Fig. 95. thin and transparent The contents are resolved into contractile fibrille and as to allow the ulti- Se targa i an interstitial substance. mate fibrille to be : F a : Reati. The contractile fibrilla constitutes the primary ele- ment of striped muscle. It is a minute column whose surface, according to Rouget, exhibits the alternate prominences and depressions of the turns of a more or less fine screw; and which, according to Bowman, is formed by a mass of small discs, named by him the sarcous elements. The znterstitial substance, granular and nucleated, unites the fibrille in the interior of the sarcolemma and, ; ae shies ; MUSCULAR FIBRE BROKEN ACROSS, SHOWING hs eu ue to Dowmon's THE UNTORN SARCOLEMMA conNecTine “YPOthesis, the discs entering into THE FRAGMENTS. the composition of each fibrilJa. The aggregation of the fibrille produces the longitudinal striation: the transverse striation is the result Fig. 96. enormous muscle in the smaller Ruminants, is represented in Solipeds by two consider- able muscles, much more voluminous than the muscle analogous to the great pectoral. It is only necessary, in this case, to change their names into superficial and deep pectorals. GENERAL CONSIDERATIONS ON THE STRIPED MUSCLES. 179 either of the helicoid disposition of the fibrille, or of the fusion of the sarcous elements which compose the latter, according to the admitted opinion as to the structure of the contractile element. The muscular fibres are united parallel to each other to form secondary fasciculi, which are surrounded by a con- junctival sheath—the perimysium. The secondary fasciculi are laid together to constitute more voluminous fasciculi which, in their turn, form the entire muscle. The conjunctival sheath enve- loping the muscle is named the eaternal perimysium. B. Trenpons anp AProngvrosEs.—The tendons are white, nacreous, round, or flattened cords fixed to the extremities of the long muscles. They are composed of fasciculi of condensed conjunctival tissue, affecting a parallel direction, and united to one another by connective sheaths. The aponeuroses belong almost ex- clusively to the wide muscles; they are Fig. 97. TRANSVERSE SECTION OF FROZEN MUSCLE, MAGNIFIED 400 DIAMETERS, N, Nerve; M, Muscular fibre, surrounded formed of several planes of parallel fibres which are not intercrossed in their middle part; at their superficies, how- ever, the fibrous fasciculi are matted toge- ther in a more or less inextricable manner. It is very interesting to study the mode of union of the muscular fibres with the tissue of the aponeuroses and by portions of six others——a, Nucleus of the nerve sheath; b, Nucleus of the sarcolemma; c, Section of nucleus of terminal plate of nerve; d, Transverse section of terminal plate, surrounded by granular material; e, Transverse section of muscle nuclei; f, Fine fat drops. The angular dark particles are sections of sarcous elements: the clear intervening spaces represent the fluid tendons, as well as the reciprocal rela- isotropal part of the muscle substance. tions of these two parts. The muscular fibre may be found passing in the same direction as the tendon, or it may fall upon the latter obliquely. In both cases there is no insensible transition between the muscular fibre and the fasciculus of the fibrous tissue ; on the contrary, the contractile fibre terminates by a rounded extremity, which is buried in a corresponding depression in the tendon or aponeurosis. The union of the muscular with the fibrous tissue is very intimate ; when the muscles are submitted toa degree of traction sufficient to cause a rupture, this never happens at the point of union. ; The tendons commence sometimes by a hollow cone, which receives on its internal face the insertions of its muscular fibres; and sometimes by a thin point, often divided, which is plunged into the substance of the muscle. It is worthy of remark that a muscle provided with two tendons shows the first-enamed arrangement at one of its extremities, and the other at its oppo- site extremity ; so that all the fibres which compose the muscle offer nearly the same length, those which leave the summit of the internal tendon being fixed to the bottom of the hollow cone formed by the second tendon, and so iprocally. = seca ie fibres which are continued by the fibrous fasciculi may be divergent or parallel. In the first case—the diaphragm, for example—the connective fibres run in the same direction as the muscular fibres. In the second case, several arrangements may be observed : 180 THE MUSCLES. 1. Tendons may pass in the same direction as the muscular fibres. This is the most simple manner. But the muscle may be divided into two bodies or bellies by a middle tendon ; it is then called a digastric muscle. 2. Muscular fasciculi, passing altogether from the same side to become anited into a tendinous cord, constitute a semi-penniform muscle. 3. Muscular fasciculi may be implanted to right and left of the tendon, m a pennated or penniform muscle. ae eenvennett Be a demonstrates that the length of the muscle, the length of its belly, and the length of its muscular fibres, should be care- fully distinguished. The first term is applicable to the whole of the muscle, the tendon included ; the second, to the fleshy body of the muscle, with the exception of the tendon; the third, to the muscular fasciculi constituting this fleshy body: the latter idea is the most important, for it alone indicates the amount of contraction a muscle is sus- ceptible of, and consequently the possible ex- tent of movement it is capable of effecting.”— Beaunis and Bouchard. C. Vessens anp Nerves.—The muscular tissue receives much blood; the fibrous tissue very little. The arteries are large, numerous, and each is acecompanied by two veins. The capillary vessels anastomose in such a manner as to form rectangular meshes, whose greatest diameter is directed towards the length of the muscle. The lymphatic vessels of the muscles are few; they sometimes penetrate their interior in following the capillaries; at other times they remain on the surface, in the external perimysium. The exist- ence of lymphatics has not yet been demonstrated in tendons, aponeu- roses, or synovial membranes. The nerves emanate from the cerebro-spinal centre. At their terminal extremity they offer a small enlargement, called by Rouget the terminal motor plate, and by Doyére and Kiihne the ner- vous colline (hillock). It is ad- mitted that the motor tube traverses the sarcolemma, losing its enve- lope; and that the substance of the DISTRIBUTION OF CAPILLARIES IN MUSCLE, Fig. 99. PORTION OF AN ELEMENTARY MUSCULAR FIBRE, a WITH FOUR DARK-BORDERED FIBRES (a) CROSS- ING ITS SURFACE; after Beale. Capillary blood-vessel, with fine nerve-fibres; a few only of the transverse markings of the muscle are represented; c, Two of the dark- bordered nerve-fibres passing over the ele- mentary fibre to be distributed to adjacent fibres. This arrangement, in which a dark- bordered nerve-fibre, distributed to muscle, divides into branches, one of which passes to a vessel, while the other ramifies upon a muscle, is frequent. Magnified 700 diameters, cylinder is spread over the surface of the muscular fibrille to form the motor plate or nervous colline. PHYSICO-CHEMICAL PROPERTIES OF STRIPED MUSCLES. Muscles are soft organs, re- markable for their more or less deep-red colour, which varies with the species, and even in these with the age and health of the animals. GENERAL CONSIDERATIONS ON THE STRIPED MUSCLES. 181 By desiccation, muscles become hard and brown ; by repeated washing they assume a straw-yellow tint. Muscles are extensible and elastic; they are also tenacious, and their tenacity is more marked during lite than after death. It has been remarked that the juice impregnating the muscular tissue is distinguished from the serum of the blood by anacid reaction. (The fluid or “muscle plasma” obtained by pressing flesh, is either neutral or slightly alkaline. It soon coagulates and separates into two portions—a semi-solid portion, “myosin,” and the fluid serum that at ordinary temperatures quickly acquires an acid reaction.) It holds in solution a variable quantity of albumen, casein, fat, a little creatine, creatinine, and a somewhat large proportion of lactic acid. The solid substance of the muscle may be partly transformed into gelatine by boiling in watcr; but its largest portion is a nitrogenous substance, soluble in dilute hydrochloric acid, called “ syntonine,” or muscular fibrine ; it differs but little from the fibrine of the blood. PHYSIOLOGICAL PROPERTIES OF THE STRIPED MUSCLES, In this paragraph will only be discussed the development of the muscles, muscular contractility, and the part the muscles assume in locomotion. A. DrEvELopmMENT or THE Muscies.—A muscle is derived from a mass of embryonic cells. Each cell becomes considerably elongated, and its nucleus becomes multiple, to constitute a muscular fibre. The membrane of the cell, enormously developed, forms the sarcolemma, while the contents of the cell, becoming more dense, divide longitudinally and give rise to the contractile fibrille. Lastly, when the muscles are formed, they grow by the augmenta- tion in length and thickness of the primary fasciculi or muscular fibres. 3B. Muscutar Conrracrisitiry.—Muscles possess the property of con- tracting under the influence of a natural or artificial stimulus. Muscular contraction is the phenomenon resulting from the operation of this property. Muscles in a state of contraction are the seat of physical and chemical phenomena ; they change their form and consistency,and become the theatre of a relatively abundant production of carbonic acid. creatinine, and inosinic acid. During contraction, it has been remarked that the muscular fibres contract by increasing in volume, like an india-rubber tube left to itself after being extended : the zig-zag doubling mentioned by Prevost and Dumas has not been observed. But these physical and chemical modifications, important as they are in Fig. 100. MUSCULAR FIBRE IN A STATE OF CONTRACTION IN THE CENTRE} THE STRI@ APPROXIMATED$ THE BREADTH OF THE FIBRE INCREASED; AND THE MYO- LEMMA RAISED IN VESICLES ON ITS SURFACE. a physiological point of view, cannot longer be dwelt upon here. It is parti- cularly important to speak of muscular contraction. A muscle that contracts becomes shortened ; its two extremities approach each other if they are free ; or one draws near the other if the latter is fixed 15 182 THE MUSCLES. to an immovable point. If the extremities of a muscle are attached to two movable levers, its contraction will bring about the displacement of one or other of these; from this a movement is produced. : p 2 The degree of shortening of a muscle varies, according to its being entirely free, or having a resistance to overcome. The mean limit of this shortening is about one-fourth the length of the muscular fibres; from this it will be understood that the movement produced by the contraction will be in proportion to the length of the fibres; though in this appreciation it will be necessary to keep in mind the density and energy of the fibre, as well as the intensity of the contractile stimulant. ran As each fibre represents a force independent in its action, it results that we may judge of the power of a muscle by the number of its fibres, or its volume. Muscles are often aided in their action by mechanical conditions: such as the disposition of the levers on which they act, the direction of the muscular fibres in connection with these levers, and, lastly, by the presence of lamelle or elastic cords. C. Uses or Muscrxs.—There are flexor, extensor, abductor, adductor, rotator, and other muscles, for all the movements of which the articulations are the centre. To determine the functions or uses of the muscle, it is sufficient to know their insertions, and the mode in which the bones furnishing these insertions articulate with each other. The result of muscular contraction. being influenced by the form of their principal axis, and the length and direction of their levers, it is necessary to briefly examine these two points; 1. The immediate effect of the contraction of rectilinear muscles is the ap- proximation of the bones to which they are attached. This approximation is usually brought about by the displacement of a single ray: that which receives the movable insertion of the muscle. Sometimes, however, the two rays move simultaneously, or they are alternately fixed and movable. The first result produced by a curvilinear muscle is the straightening of its component fibres ; after which it may act on the bony levers as do the rectilinear muscles, if its contractile power be not entirely expended. When a muscle is quite circular, its only action is to contract the opening it circum- scribes. With regard to the inflected muscles, their action can only be estimated from their point of'inflexion ; they operate as if this point represented their origin or fixed insertion. 2. The muscular powers are submitted to the statical and dynamical laws which govern the theory of levers, for the bony rays are only levers moved by the muscles. In the locomotory apparatus we find the three kinds of lever recognised by physicists. Thus the head, extended by the great complexus muscle, represents an interfixed, or lever of the first class ; the foot, extended by the gastrocnemii muscles, offers an example of the interresisting, or second kind, when this member remains fixed on the ground ; lastly, the lower jaw raised a aa the upper by the masseter muscle, forms an interpuissant or third ind. It is worthy of remark that the arm of resistance in the bony levers is always extremely long ; a circumstance which favours speed and the extent of movement at the expense of power. On the other hand, muscles are rarely perpendicular to the arm of their GENERAL CONSIDERATIONS ON THE STRIPED MUSCLES. 183 levers, at least at the commencement of their action ; another circumstance which again diminishes their energy. APPENDAGES OF THE MUSCLES. These are: 1, The enveloping or contentive aponeuroses; 2, The serous or mucous burse; 3, The tendinous and synovial sheaths. A. Cortrntive Apongvroses.—These are layers of white fibrous tissue, which envelop, in common, all the muscles of one or several adjoining regions, principally those of the inferior rays of the limbs, where they con- stitute a kind of hollow cylinder. These aponeuroses are formed by very resisting interwoven fibres, which are attached to the bones at numerous points. At their periphery they receive the insertion of one or several muscles, which keep them more or less tense. Their external face responds to a thin fibro-cellular layer that separates them from the skin. The internal face sends lamellar prolong- ations between the muscles, which are destined to isolate these organs in special sheaths. The aponeuroses maintain the muscles in their position, and sustain them during their contraction. B, Szrous Bursm.—The serous or mucous burse are small cavities, filled with a serous fluid, which are met with at those points where the muscles glide over resisting surfaces. They are generally orbicular or rounded, and their interior is often divided by fibrous bands. Their walls are formed by slightly condensed conjunctival tissue, and may be lined by a pavement epithelium; in which case it is believed that the serous bursa is produced by the simple dilatation of one of the con- junctival meshes. “©. Trexprnous SHearus anp SynoviaL Mempranus.—Tendinous sheaths is the name given to the half-bony, half-fibrous, sometimes exclusively fibrous, gliding grooves into which the tendons pass when they are inflected to change their direction. acs The tendinous synovial membranes are serous membranes lining the ten- dinous sheaths and covering the tendons at the points where these two parts correspond. They secrete a synovial fluid quite like that of the articulations. When they almost completely envelop the tendon, and are afterwards carried to the walls of'the sheath, they are termed vaginal. Their walle are composed of: 1, A very fine conjunctival membrane, con- founded by its external face with the tendinous sheath, by the other face with the tendon; 2, A simple layer composed of pavement epithelium, extended over the whole or a part of the internal face of the conjunctival membrane. MANNER OF STUDYING THE MUSCLES. A. Oxasstrtcation.—To facilitate the study of the muscles, two methods may be employed in grouping them. The first consists in classifying them according to their uses ; describing, for example, all the flexors, extensors, etc., of the same region. In the second method, the uses of the muscles are not taken into account, their relations only being considered; and they are divided into groups or regions, which comprise all the muscles situated around a bony ray. The latter is the method now adopted, because it is the most convenient, useful, and rational. ; Ensiaok, (Leyh describes the muscles by layers, or according to their situation, 184 THE MUSCLES. which, he asserts, facilitates the study of anatomy in a surgical point of view). B. PREPARATION.—We Will limit ourselves to some general remarks on the following joints : ‘ Choice of a subject.—If there is for disposal a certain number of subjects from among which it is possible to make a selection, the preference should be given to those that have the muscular system best developed; not that large, soft, lymphatic horses with enormous masses of muscle should be chosen, for these animals are always less convenient than small or middle-sized, well-bred horses. Asses and mules, when very emaciated, answer well for the preparation of the muscles. — Position of the subject.—It is necessary to place the subject, immediately after death, in a convenient position, in order that the cadaveric rigidity may set in while it isin that attitude. Without this precaution, the various parts of the body may assume an incon- venient shape or direction, and all attempts to amend them will prove almost unavailing, particularly in the larger animals. Three principal positions may be given to subjects: 1. The animal is in the first position when it is placed on its back, the four ex- tremities in the air, and maintained in that posture by means of long cords passed round the pasterns and fixed to the movable rings which terminate the extremity of the four bars of the wheeled-table on which the subject is laid. The head should be beyond the end of the table and rest upon a stool. The animal should always be placed in such a manner that the head be opposite the fore-part of the table, so that the movements of the pole or shaft be not impeded during the displacement of the apparatus. In order that the neck be not twisted to the right or left, in attaching the fore-limbs the subject should be raised so that the withers rest lightly on the table. According to the bulk of the animal and the length of the bars, the ropes should be passed around either the pasterns, above the fetlocks, or even above the knees. 2. To place the animal in the second position, it is turned on the belly, the two thighs flexed, the extremities carried beyond the table, and the head fixed between two bars by means of a rope passed under the zygomatic arches. 3. The subject is in the third position when it rests on its side. Rules to be observed during the preparation.—1. By no means, if possible, remove the skin from the regions to be dissected until quite ready to begin the dissection. If this is impossible, then take the precaution of enveloping these regions in damp cloths, or in the animal’s skin, to prevent desiccation of the aponeuroses and the superficial muscles. 2. To dissect a muscle, it is necessary to remove the aponeuroses or the other muscles which cover it, the cellular tissue enveloping it, and the fat, glands, vessels, and nerves lodged in the neighbouring interstices. The aponeuroses should be removed in shreds by making them very tense with the forceps, but without raising them, and causing the blade of the scalpel to glide between the fibrous and muscular surfaces, keeping it always parallel to these two planes. The covering muscles should not be entirely excised, hut ought to be cut through the middle, across their fibres, and the ends thrown back; in this way it is always possible to replace a muscle by bringing the two portions together ; the study of its relations is then much more easy. The cellular tissue is got rid of by removing it with the forceps, and carrying the edge of the scalpel in the re-entering angle formed by the cellular layer and the surface of the muscle. This method also suffices for removing aponeuroses when they are slightly adherent to the muscular fibres. But when they give attachment to these by their under face, as may be noticed in the external scapular aponeurosis, it is neevssary to have recourse to the method indicated above. To remove fat, glands, etc., scissors will be found very advantageous. Order to follow in preparing all the muscles of the same subject, and to derive mast advantage therefrom.—l. Place the subject in the first position, and commence by study- ing the muscles of the inferior abdominal region. Then excise them, leaving the posterior extremity of the great pectoral muscle, the prepubic tendon, and the crural arch intact. The abdominal cavity having been emptied of the viscera it contains, dissect and study successively the diaphragm, the internal crural region, except the deep muscles, the sublumbar region, the femoral and posterior crural regions, the superficial muscles of the inferior cervical region, and the pectoral region. 2. After detaching for future use one of the anterior limbs, the animal is placed in the second position, and one after another may be dissected the muscles of the ear, those of the superior cervical region, the croup and costal regions, except the triangular muscle, and the spinal region of the back and loins, GENERAL CONSIDERATIONS ON THE STRIPED MUSCLES. 185 8. The regions of the anterior limb may be prepared at the same time, or immediately afterwards, 4. Separate the two posterior limbs by sawing the femurs through their middle, and proceed to the dissection of the muscles of the posterior leg and foot. 5. By means of another application of the saw across the middle of the loins, the pelvis is completely isolated for the preparation of the coceygeal muscles, and the deep cee of the internal crural region, nearly as they are represented in figures 90 and 131. 6. The animal being placed on its side. the pectoral cavity is opened by sawing through the ribs near their extremities; on the two particular portions thus obtained may be studied, in one part, the triangularis of the sternum, and in the other the deep muscles of the inferior cervical region, including the long muscle of the neck and the anterior and lateral straight muscles of the head. 7. Lastly, the head is disarticulated and the muscles of this region are prepared The subject may afterwards serve for the study of nearly all the articulations. Preservation of the muscles.—The muscles may be preserved by immersing them in appropriate fluids, and the muscular preparations by drying them. A large number of liquids preserve muscles from putrefaction. We may mention alcohol ; a mixture of alcohol and spirits of turpentine; alcohol, water, and chloroform ; a solution of sulphate of iron, bichloride of mercury, or arseniousacid. The best preservative fluid, however, is nitric acid diluted with water, in the proportion of one of the former to three of the latter. The acid hardens the muscles and softens the conjunctival tissue; this allows all the interstices to be completely cleared out, and even permits the primitive muscular fasciculi which have been concealed by the white tissues to be exposed. Desiccation, after immersion in a bath of arsenious acid or sulphate of iron, causes the muscles to become hardened and deformed. It is therefore a bad procedure. (A careful dissection of the muscles, with regard to their origin, insertion, action, and relations, is of infinite importance to the student of human anatomy; to the Veterinary Student itis no less important, and more particularly with reference to the muscles of the limbs. A correct knowledge of their situation, attachments, and functions is often the only guide the Veterinary Surgeon can rely upon in the diagnosis of those apparently obscure cases of lameness which are of such comparatively frequent occurence. In the words of Mr. Henry Gray, we may repeat that “an accurate knowledge of the points of attachment of the muscles is of great importance in the determination of their action. By a knowledge of the action of the muscles, the surgeon is able at once to explain the causes of displacement in the various forms of fracture, or the causes which produce distortion in the various forms of deformities, and, consequently, to adopt appropriate treatment in each case. The relations also of some of the muscles, especially those in immediate apposition with the larger bloodvessels, and the surface markings they pro- duce, should be especially remembered, as they form most useful guides to the surgeon in the application of a ligature to these vessels.” —‘ Anatomy, Descriptive and Surgical. An accurate knowledge of the muscular system is also of great service to the Veterinary Surgeon in estimating the value to be placed upon the external conformation presented by animals intended for different kinds of labour. “In dissecting,” says Mr. Holden, “there are four principal objects to be constantly borne in mind by the student: 1st, The impression on the memory of those facts of general anatomy taught in the lectures. 2nd, Ihe study of those parts of the body more especially concerned in surgical affections and operations. 3rd, The education. of the sense of touch, and of the hand in the use of instruments; and 4th, The education of the eye in the knowledge of the several tissues of the body, in various positions, and varying circumstances. . . . The education of the eye is a gradual and tedious process, but one which is pretty certain to be satisfactorily accomplished if the student, do but use his hands properly, and therefore a few words on the manual part of dissection may - not be out of place. ’ eres ' “First, as to the instruments requisite for dissection. A case, containing six or eight scalpels, two pairs of scissors, a pair of dissecting forceps, a set of chain-hooks, a blow- pipe, and a probe, will enable the student to make all requisite dissections, supposing that he is allowed the use of a saw and chisel in the dissecting-room. Great variety exists in dissecting-cases, both as to form and expense, but so long as the instruments themselves are strong and good, the simpler the case the better. Scalpels for dissection are made of two principal shapes; in one, the edge is bevelled to the point, the back being straight; in the other, both back and edge are bevelled to a point midway between the two. The latter form is preferable for most purposes. The blade should not be more than an inch and a half long, and never double edged ; but the material of which the handle is constructed is a matter of indifference, 186 THE MUSCLES. “For all ordinary dissection, it will be found most convenient to hold the scalpel like a pen; but for cleaning the fascia off museles, and following out small nerves, it is better to hold it reversed, so that the back of the knife may be against the tissue which is to be preserved. In making the first incision through the skin of a limb, or in any other position where a long incision is required, the knife may, with advantage, be held under the hand, by which the wrist has more play, and the student has the opportunity of practising a mode of holding the knife, which he will find very useful when operating on the living body. ; “The forceps should be broad at the extremities and coarsely serrated, so that it may retain a firm hold on small portions of tissue. It is very important that the forceps should not be too strong in the spring, for in that case it becomes so fatiguing to the hand that it is impossible to continue its use for any length of time. The forceps should be held lightly between the thumb and the first and second fingers of the left hand, which may be steadied by resting the little finger on a neighbouring part. “The chain-hooks should be strong, and bent in the direction of the thickness and not of the breadth of the steel, as is sometimes done. These latter are very inferior, being liable to be unbent under any considerable strain. Care should be taken that the chains are firmly linked, and that the central ring is sufficiently stout to bear any force that may be applied. The scissors should be large and strong, and it will be found advantageous to have one curved pair, which is very useful in preparing the ligaments. “The student will do well to bear in mind that he will probably be called upon in after life to operate on the living body, the only true preparation for which is careful dissection; he should therefore, as far as possible, conduct all his dissections as methodically, and with as much care, as if operating on the living body. “Phe student should bear in mind that his manual labour is only a part of his duty, and will be thrown away, unless he at the same time study the description of the part upon which he is engaged; he should not, therefore, carry the dissection further than he can learn the description on the same day, and at the subject, and should, if possible, re-peruse the description in the evening, and always on the next morning, before carrying the dissection any further.”) CHAPTER II. THE MUSCLES OF MAMMALIA. Articte I.—Musoies oF THE TRUNE. SUBCUTANEOUS REGION. Tus only comprises a single muscle, the fleshy panniculus (panniculus carnosus), destined to move the skin covering the trunk. Strictly speaking, however, we may describe as dermal muscles all those which are attached to the inner surface of the superficial integument—the muscles of the face, for example. : Fleshy Panniculus, Preparation.—Place the-animal on its side, and carefully remove the ski i the cuticular muscle to remain on the subjacent muscles. ai ee Situation—Form— Extent.—Situated on the inner surface of the skin cover- ing a am of the ees and abdomen, the fleshy panniculus is an immense road muscle, irregularly triangular in shape, thin i thicker in the middie ith pie ee a The upper border corresponds to a curved line, convex superiorly, and extending obliquely from the flank to the withers. ‘The inferior border is carried horizontally from the flank to the posterior border of the olecranian mass of muscles, passing along the upper margin of the great pectoral mauscle, which it covers, and to which it adheres somewhat closely. The MUSCLES OF THE TRUNK. 187 anterior border descends from the superior extremity of the shoulder on to the muscles of the fore-arm., Structure—Attachments.—The fleshy fibres entering into the composition of this muscle are directed forward for its posterior two-thirds; but on arriving on the shoulder they gradually straighten and become vertical. They are continued, on the margins of the muscle, by aponeuroses which attach it either to the internal surface of the skin or to the fibrous fascia of the superficial muscles. This muscle has, besides, a very remarkable insertion into the humerus, which was noticed by G. Cuvier, in his ‘Lecons d’Anatomie Comparée,’ and which appears to have been omitted, at least so far as Solipeds are concerned, in every treatise on Veterinary Anatomy. The following is what we have often observed in this respect :—On reaching the posterior border of the ulnar mass of muscles, the panniculus divides into two superposed layers: one, superficial, is carried to the muscles of the anterior member ; the other, deep, soon terminates by an aponeurosis which is united to the great pectoral muscle, and is bordered at its upper margin by a nacrous aponeurotic band, which penetrates between the thorax and the muscles of the arm to be fixed to the small trochanter. Relations.—By its superficial face, with the skin, to which it closely adheres ; by its deep face, with the great dorsal, the dorsal portion of the trapezius, the abdominal tunic, the great oblique muscle of the abdomen, the great serratus, some external intercostals, the spur vein, and the superficial muscles of the shoulder and arm. Action.— The animal, in contracting this muscle, shakes the whole of the cutaneous integument which covers it; thus preventing insects from alighting on the surface of the body, or tormenting by their bites or stings. In the Dog, the panniculus carnosus is prolonged over the croup, and is united along the dorso-lumbar spine to that of the opposite side. It is very developed in the Cat. CERVICAL REGION, This region comprises all the muscles grouped around the cervical vertebre—muscles which are conspicuous by their volume and the important part they play in the animal economy. There are described a superior and an inferior cervical. A. Superior Cervical, or Sptnal Region of the Neck. This includes seventeen pairs of muscles, which are: the cervical portion of the trapezius, rhomboideus, angularis of the scapula, splenius, great compleaus, small complexus, transverse spinous of the neck, the six intertransverse muscles of the neck, great oblique muscle of the head, great posterior rectus, and small pos- terior rectus. These form four superposed layers on each side of the cervical ligament, and occupy the triangular space circumscribed by the upper border of that ligament, the transverse processes of the vertebra of the neck, and the spinous process of the second dorsal vertebra. Preparation.—Place the subject in the second position and dissect in suecession the four layers of the region. To study the first layer, which is formed by the cervical portion of the trapezius, remove the skin, cellular tissue, and the fibrous fascia covering that muscle (See fig. 102). The preparation and study of the second layer, composed of the thomboideus, angularis. and splenius, is curried out in two stages. In the first. the trapezium and the mastoidu-humeralis is removed, leaving only the cervical insertions For the description of this muscle, see the Srinat Reeton of the back and loins. 188 THE MUSCLES, of the latter muscle; then the limb is removed by sawing through the scapula beneath the insertions of the angularis and great serrated muscles, as in figure 105. But as neither the cervical or dorsal insertions of the splenius are exposed, it is necessary to proceed to the second part of the operation by removing the rhomboideus, angularis, and the superior extremity of the shoulder. To prepare the third layer, which com- prises the great and small complexus, it is sufficient to excise the splenius, in following the direction of the neck, and to turn upwards and downwarus the two portions of the muscle (See fig. 106). Lastly, the deep layer—the transverse spinous, intertransverse, oblique, and posterior straight muscles, as well as the cervical ligament—is exposed by removing the two complexus and the ilio-spinalis muscles (See fig. 104). 1. Rhomboideus. (Figs. 101, 6; 104, 1, 2.) Synonyms.—Described by Bourgelat as two muscles, the proper elevator of the shoulder and the rhomboideus, these were termed by Girard the cervico-subscapularis and dorso-subscapularis. (This is the rhomboideus longus and brevéy of Percivall, and the dorso-scapularis and cervico-subscapularis of Leyh.) : Form—Situation—Direction.—This muscle has the form of 4 very elongated triangle, and is situated at the inner aspect of the cervical trapezius and the scapular cartilage. beneath the cervical ligament, whose direction it follows. Fig. 101. LATERAL VIEW OF THE NECK; SUPERFICIAL MUSCLES. 1, 1, Parotid gland; 2, Sterno-maxillaris and, 14, Its juncti ith i rotid : Junction with its fellow of th opposite side; 3, 4, Mastoido-humeralis, or levator humeri; 5, Spleniues 6, Rhomboideus ; 7, Funicular portion of the cervical hgament, or ligamentum ie ; s ig eo the scapula; 9, Supra-, or antea-spinatus; 10, Trapezius; nira-, or postea-spinatus ; i in; i ie coe Pp pinatus; 12, Jugular vein; 13, Subscapulo-hyoideus ; Structure—Attachments.—It is composed of thick iculi anterior of which are oblique downwards and ae nae passing directly downwards. These fasciculi are fixed by. their superior extremity to the funicular portion of the cervical ligament and the summits of the spinous processes of the four or five dorsal vertebree succeeding the MUSCLES OF THE TRUNK, 189 first—fixed insertion ; by their inferior extremity, to the inner aspect of the scapular cartilage, where the anterior fasciculi are confounded with those of the angularis. Relations.—Covered by the cervical portion of the trapezius, the scapular cartilage, and the aponeurosis of the great dorsal muscle, the rhomboideus covers the sphenius, which is excavated near its superior border for its reception, as well as the aponeurosis of the anterior small serrated muscle through the medium of a yellow elastic lamina. Action.—It draws the shoulder upwards and forwards. “2. Angularis Muscle of the Scapula. (Figs. 102, 4; 105, 3.) Synonyms.—Trachelo-subscapularis—Girard, Portion of the serratus magnus —Bourgelat. Elevator of the scapula—Cuvier. (Anterior portion of the serratus magnus of Percivall. The levator anguli scapule of Man.) Situation—Form—Structure.—This is a very strong muscle, situated in front of the shoulder, triangular, flattened on both sides, thin at its superior border, thick behind and below, and almost entirely fleshy. Attachments.—It takes its origin from the transverse processes of the five last cervical vertebrae by five distinct portions, which are directed towards the scapula in converging towards each other, and soon join to form a single muscular body, which is inserted into the internal face of the scapula, on its anterior triangular surface. Relations—This muscle is confounded at its inferior border with the serratus magnus. It is covered by the cervical trapezius, the mastoido- humeralis, and the small pectoral muscle. It covers the splenius, the in- ferior branch of the ilio-spinalis, and the common intercostal muscle. Nea its junction with the serratus magnus, its internal face adheres very closely to the transverse processes of the three first dorsal vertebre. Action.—It draws forward the superior extremity of the scapula, while the humeral angle is carried backwards. If the shoulder becomes the fixed point, it can act in the extension or lateral inclination of the neck. 8. Splenius. (Figs. 105, 4,5; 106, 5.) Synonyms.—Cervico-trachelian — Girard. Form—Situation—A considerable muscle, flattened on both sides, triangular, and comprised between the cord of the cervical ligament, the inferior branch of the ilio-spinalis muscle, and the transverse processes of the four first cervical BB: vert ebrae Structure—The splenius, aponeurotic only at its periphery, is composed of thick fleshy fasciculi which are all directed forwards and upwards, to reach the head and the first cervical vertebra. Attachments.—It is fixed, by its posterior border, to the lip of the cervical ligament and the summits of the spinous processes of the first dorsal vertebra, by means of an aponecurosis which is ccntinuous behind with that of the small anterior serratus, and confounded, by its inner surface, with that of the great complexus. Its anterior border is cut into four or five digitations which constitute the movable insertions of the muscle: a, The superior digitation is the widest and thinnest, and terminates in an aponeurosis (Fig. 105, 5), which unites it to the mastoid tendon of the small complexus, and passes to the mastoid crest. b. The second joins a very strong tendon common to the splenius, the small complexus, and the mastoido-humeralis, which tendon is attached to the transverse process of tay Np we 190. THE MUSCLES. the atlas (Fig. 105, 9). ¢, d. The two or three others are directly inserted into the transverse processes of the third, fourth, and fifth cervical vertebre. Relations.—The splenius is related, outwardly, to the rhomboideus, the angularis, cervical trapezius, and mastoido-humeralis ; inwardly, to the two complexus and two oblique muscles of the head ; by its inferior border, to the superior margin of the inferior branch of the ilio-spinalis (longissimus dorsi). ince extends the head and neck in inclining them to one side. If the two act in concert, the extension is direct. c Fig. 102. SUPERFICIAL MUSCLES OF THE NECK AND SPINAL REGION OF THE BACK AND LOINS. 1, Dorsal trapezius; 2, Great dorsal; 3, Cervical trapezius; 4, Levator anguli scapule; 5, Splenius; 6, Anterior, or superficial portion of the mastoido-hume- ralis; 7, Its humeral insertion; 7’ Its mastoid insertion ; 8, The thin aponeurosis uniting this insertion to the sterno-maxillary, muscle; 8‘, Posterior portion of the mastoido-humeralis; 9, Its inferior a att inserted into the interstice of the long abductor of the arm; 10, Sterfio-maxillaris; 11, Subscapulo-hyoideus; 12, Portion of the dermal muscle of thé neck ; 13, Portion of the’ great extensor of the fore-arm; 14, Posterior belly of the long abductor of the arm; 15, Great pectoral muscle. MUSCLES OF THE TRUNE. 191 4. The Great Complexus. (Fig. 106, 6, 7.) Synonyms.—Dorso-occipitalis—Girard. (Complexus major—Pereivall.) Situation—Direction—Form.—A powerful muscle, included between the internal surface of the splenius and the cervical ligament, whose oblique direction forwards and upwards it follows; it is triangular, flattened on both sides, elongated from before to behind, and divided longitudinally into two unequal portions—a posterior and anterior. Structure.—The posterior portion (Fig. 106, 6), the most considerable, is aponeurotic at its origin, intersected by linear fibrous bands which obliquely cross its direction, and is formed of fleshy fibres directed forwards. Those which compose the anterior portion (Fig. 106, 7), intermixed with some tendinous fasciculi, are directed upwards, and appear to be inserted into the preceding. It is this difference in the direction of the fibres of the two portions of the great complexus which allows them to be distinguished from one another; the two being only really separated by an interstice near their inferior extremity. Superiorly, the muscle is constricted to form the summit of the elongated triangle it represents, and terminates by a strong tendon. Fixed insertions.—The posterior portion derives its origin: 1, From the summit of the spinous processes of the first dorsal vertebre, by a strong aponeurosis which is confounded with that of the splenius and the anterior small serratus; 2, From the transverse processes of the four or five dorsal vertebrae which follow the second, by as many aponeurotic digitations united by their margins. The anterior portion is fixed: 1, To the transverse processes of the two first dorsal vertebra, by two tendinous digitations analogous to those of the posterior portion; 2, To the articular tubercles of the cervical vertebra’, by the inferior extremity of its fleshy fasciculi. Movable insertion.—The movable insertion of the great complexus is effected through its superior tendon, which is fixed to the posterior face of the occipital protuberance, beside the cervical tuberosity. Relations.—It is covered by the splenius and the small complexus. It covers the cervical ligament, the upper branch of the ilio-spinalis, the trans- verse spinous of the neck, and the oblique and posterior straight muscles of the head. The aponeurotic digitations which attach it to the dorsal trans- verse processes are comprised between the two branches of the ilio-spinalis. The interstice which separates, inferiorly, the two portions of the muscle affords a passage to the superior cervical artery. Action.—It is a powerful extensor of the head. 5. Small Complexus. (Figs. 105, 6, 7; 106, 8, 9.) Synonyms.—Dorso-mastoideus— Girard. (Trachelo-mastoideus—Percivall.) Situatton—Direction—Situated at the internal face of the splenius, in an oblique direction upwavdé and forwards, this muscle lies along the anterior border of the great complexus, and follows the inferior branch of the ilio-, spinalis, which it appears to continue to the head. = Form—Structure—The small complexus is a long muscle, divided into two fleshy, fusiform, and parallel portions—anterior and posterior—which we might strictly consider as two distinct muscles. Both are composed of successive fasciculi, which become longer as they are superficial, and ‘terminate by a tendon at their superiér extremity. The tendon of the posterior muscle is flattened, and joins the mastoid aponeurosis of the 192 THE MUSCLES. splenius. That of the anterior muscle is funicular, and receives, before its insertion, a digitation from the splenius (fig. 106, 10), and another from the mastoido-humeralis (fig. 106). ; Fixed attachments.—The two fleshy portions of the small complexus have their fixed insertion in common with the anterior portion of the great com- plexus: 1, On the transverse processes of the two first dorsal vertebrae, through the medium of aponeurotic digitations which serve as an origin to the last-named muscle; 2, On the articular tubercles of the cervical vertebra, by the inferior extremity of their component fascicili, : Movable attachments.—The terminal tendon of the posterior muscle passes to the mastoid process of the temporal bone. The anterior passes to the transverse process of the atlas. LATERAL VIEW OF THE NECK; MIDDLE LAYER OF MUSCLES. 1, Funicular portion of the cervical ligament; 2, Complexus major; 3, Complexus minor; 4, Rectus capitis posticus major; 5, Rectus capitis posticus minor; 6, Stylo-maxillaris; 7, Carotid artery; 8, Pneumogastric nerve and branch of sympathetic; 9, Longus colli; 10, Recurrent nerve; 11, Inferior scalenus; 12, Spinalis, or transversalis colli; 13, Incision through rhomboideus and trapezius ; 14, Trachea, Relations.—Outwardly, with the splenius; inwardly, with the great eomplexus and the oblique muscles of the head. . The tendon of the posterior fleshy portion is covered by the mastoid aponeurosis of the mastoido- humeralis. en Action.—The small complexus inclines to its side the head and upper part of the neck. It also act: 3 an extensor of the head.? 1 Bourgelat has described, by the name of long transversal, the anterior portion of this muscle, and attached it to the posterior portion of the splenius. We do not know where to find one or other of these in the crude description of Lafosse and Vitet. Girard considered them, like ourselves, as a single muscle, which he designates the dorso- mastoideus. Rigot has united them with the anterior portion of the great complexus and the foremost fasciculi of the short transverse muscle Ginferior branch of the ilio-spinalis), to make his long transversal; in doing so he has only complicated their description. These two muscular fusciculi, being, to our view, exactly represented, the posterior, at MUSCLES OF THE TRUNK. 193 6. Transverse Spinous Muscle of the Neck. (Fig. 104, 4.) Synonyms.—Short spinous—Bourgelat. Dorso-spinalis—Girard. (Spinalis colli— Percivall. Transversalis colli of Man.) a Situation —Between the great complexus and the cervical ligament, on the lamine of the last five vertebra of the neck. ee Form—Structure—Attachments.—This muscle, a continuation in: the cervical region of that of the back and loins, is generally formedyof five thick and short fasciculi, strongly aponeurotic, directed forwards, upwards, and inwards. ae; These fasciculi, attached by their posterior extremities—fized insertion—to the five last articular tubercles of the cervical region, are fixed by thoir anterior or superior extremities—movable insertion—into the sixth, fifth, fourthy” third, and second spinous processes of that region. Relations.—Outwards, with the great. complexus; inwards, with the superior branch of the ilio-spinalis and the cervical ligament. By its anterior face, with the laminew of the cervical vertebra and the interlamellar ligaments. Action.—An extensor and flexor of the cervical spine. 7. Intertransversal Muscles of the Neck. (Fig. 104, 9.) Synonyms.—Intercervicals— Girard. (The intertransversales of Man. Not mentioned by Percivall.) These are six small, short, and very tendinous fasciculi, each of which is doubled into two secondary fasciculi, a superior and inferior. They are lodged in the lateral excavations comprised within the transverse and artic- ular processes of the cervical vertebre, and are carried from one vertebra to another, except from the first to the second. Covered by the cervical attachments of the majority of the muscles of the neck, they cover the vertebre to which they are attached, as well as the vertebral arteries and _ veins, and the intervertebral foramen. They incline the neck to the side. 8. Great Oblique Muscle of the Head. (Fig. 104, 7.) Synonyms.—Axoido-atloideus—Girard. (Obliquus capitis inferior—Percivall.) Form—Direction—Situation—A. short, thick, and broad muscle, oblique forwards and outwardly, and applied to the superior face of the two first vertebra of the neck. Structure and Attachments.—Its fibres are nearly all fleshy, parallel to each other, and longer as they become superficial ; they are attached by their posterior extremity—fixed insertion—to the external face of the spinous process of the axis, and by their anterior extremity—movable insertion—to the superior surface of the transverse process of the atlas. : Relations. —Outwards, with the splenius, the great and little complexus ; inwards, with the atlas, the axis, and the ptlo-axoid articulation ; above, least, by the small complexus of anthropotomists, we have thought it proper to give it. that name. With regard to the muscle generally termed | the small complexus by veterinary anatomists, following the example of Meckel we will describe it as a portion of the great posterior straight muscle of the head. ee 3 (Percivall names Girard’s axotdo-occipitalis longus the “ complexus minbr,” and his dorso-mastoideus the “ trachelo-mastoideus.” Leyh, following Girard, designates the latter muscle the dorso-mastoideus.) 194 THE MUSCLES. with the posterior straight muscles of the head; below, with the anterior eat straight muscle. : aor i ye al pivots the atlas on the odontoid process of the axis; it is, therefore, the special rotator of the head. Fig. 104, CERVICAL LIGAMENT AND DEEP MUSCLES OF THE NECK, 1, Lamellar portion of the cervical ligament; 2, Funicular portion; 3, 3, The transversales muscle of the back and loins; 4, 4, Transversales of the neck; 5, Posterior great straight muscle of the head; 6, Small ditto; 7, Great oblique muscle of the head; 8, Small ditto; 9, 9, Intertransversales of the neck; 10, Anterior great straight muscle of the head; 11, Inferior scalenus muscle; 12, Superior ditto, 9. Small Oblique. (Fig. 104, 8.) Synonyms.—Atloido-mastoideus—Girard. (Obliquus capitis superior—Percivall. Tiateral atloido-occipitalis of Leyh. Obliquus superior of Man.) A short, thick, quadrilateral, and strongly aponeurotic muscle. Its fibres are fixed posteriorly—origin—to the lip bordering the transverse process MUSCLES OF THE TRUNE. 195 of the atlas; they are carried from thence forward, upward, and inward, to to be attached—termination—1, To the styloid process of the occipital bones ; 2, To the external surface of that bone, on the imprints which border the mastoid crest posteriorly; 3, To the mastoid crest itself. This muscle is covered by the mustoid tendon of the small complexus, by the superior aponeurosis of the splenius, and that of the mastoido-humeralis. It covers the occipito-atloid articulation, the occipital insertion of the posterior straight muscles of the head, and the origin of the occipito-styloid and digastric muscles. It inclines the head on the atlas, and slightly extends it. 10. Posterior Great Straight Muscle of the Head. (Fig. 104, 5.) Synonyms. —Small complexus and great posterior straight muscle—Bourgelat. Long and short axoido-occipitalis—Girard. (Complerus minor and rectus capitis posticus major.—Perecivall. Leyh gives this muscle the same designations as Girard. It is the rectus capitis posticus major and medius of Man.) Form—Structure—Situation—Elongated, prismatic, easily divisible into two fasciculi—one superficial, the complexus minor of Bourgelat (and Per- civall) ; the other deep, the great posterior straight muscle of Bourgelat (and the rectus capitis posticus major of Percivall)—entirely fleshy, and formed of parallel fibres, this muscle is lodged, with the small posterior straight muscle, in a triangular space circumscribed by the cord of the cervical liga- ment and the internal border of the oblique muscles. Attachments.—It is attached, by its superior extremity, to the whole extent of the uneven lip which terminates the spinous process of the axis— jixed insertion. Its anterior extremity is insinuated beneath the small oblique muscle, and is fixed to the occipital bone, behind the superior insertion of the great complexus, whose tendon receives some of the fibres of the superficial fasciculus—morable insertion. Relations.—Above, with the great complexus; below, with the small straight muscle ; inwards, with the cord of the cervical ligament and the analogous muscle of the opposite side; outwards, with the oblique muscles. Action—This muscle, a congener of the great complexus, aids in extending the head. 11. Small Posterior Straight Muscle. (Fig. 104, 6.) Synonyms.—Atloido-occipitalis—Girard. (Rectus capitis posticus minor—Percivall. . The Atloido-occipitalis superior of Leyh. The rectus capitis posticus minor of Man.) A very small, wide, and triangular muscle, flat above and below, and lying immediately upon the fibrous capsule of the occipito-atloid articulation. It is attached, posteriorly, to the superior face of the atlas—origin ; in front, to the external surface of the occipital bone, below the preceding muscle, whose action it shares. B. Inferior Cervical or Trachelian Region. The muscles composing this region are situated in front of the cervical vertebre, and are, for the most part, grouped around the trachea, which they envelop as in a kind of sheath. They are eleven in number : the cuticular muscle of the neck, the mastoido-humeralis, sterno-maaillaris, sterno-hyoideus, sterno-thyroideus, omo- or’ subscapulo-hyoideus, the great and small anterior straight muscles of the head, the small straight lateral muscle, the scalenus, and. the long muscle of the neck. 196 THE MUSCLES. Preparation.—1. Place the animal in the first position, 2. Remove the skin of this region, in order to expose and study the cuticular muscle, 3. Remove that muscle and the parotid gland to prepare the mastoido-humeralis, the stylo-maxillaris, sterno- hyoideus, and sterno-thyroideus, 4. Transversely cut through the mastoido-humeralis near the angle of the shoulder, and isolate it from the subscapulo-hyoideus to expose this muscle; taking care to preserve the jugular vein and parotid gland, in order to study their relations with it. 5. Remove the fore limbs; open the thoracic cavity by sawing through the eight first ribs near their superior extremity ; take out the viscera contained in this cavity, as well as the trachea, cesophagus, pharynx, and larynx, to expose the long muscle of the neck, the scalenus, and the straight muscles of the head. 1. Subcutaneous Muscle of the Neck. (Figs. 102,12; 114, 1.) Synonyms.—It has been described by Bourgelat, and the majority of veterinary anatomists who have followed him, as two muscles: the cuticularis of the neck and the face. (Percivall includes this muscle in his description of the panniculus carnosus.) This is a membraniform expansion, partly fleshy, partly aponeurotic, which covers the muscles of the neck, the intermaxillary space, and the face. The fleshy fibres form, in front of the neck,a thin band, which is united, through the medium of a fibrous raphé, to that of the opposite side. This band is in contact with the sterno-maxillary, sterno-hyoid, subscapulo-hyoid, and sterno-thyroid muscles, as well as the jugular vein: enveloping them all as in a sort of gutter. It gradually thins from below upwards, in such a manner that around the upper part of the throat itis only composed of some scattered fibres. In the intermaxillary space, and on the expanding borders of the maxillary branches, the fleshy fibres appear again of a certain thickness, but only to become attenuated on the external surface of the cheeks. These fleshy fibres leave the anterior prolongment of the sternum? and intermediate middle raphé of the two muscles, and directing their course outwards and upwards, soon become confounded with the aponeurosis. The latter, extremely thin, is spread over the mastoido-humeralis, the superior cervical muscles, parotid region, and the cheeks, and is finally attached to the zygomatic crest. On arriving near the commissure of the lips, the cuticular muscle is united to the alveolo-labialis (or buccinator muscle) by a fleshy fasciculus named, in Man, the risorius santorini (Fig. 110, 24). The cuticularis colli braces the muscles it covers during their contraction and pulls backwards the commissures of the lips. We doubt very much whether it has, in the cervical region at least, any action on the skin, for it adheres but very slightly to its inner surface. 2. Mastoido-humeralis. (Figs. 102, 105, 106, 114.) Synonyms.—The muscle common to the arm, neck, and head—Bourgelat. Repre- senting the cleido-mastoid, and the clavicular portions of the trapezius and deltoid of ' The mastoido-humeralis may be dissected at the same time as the trapezius, the subject being placed in the second position. This conveniently permits the superior insertions of the muscle to be studied. (See fig. 102). * It will be seen, on referring to figure 114 and its legend, that we restore to the cuticular muscle of the neck the sternal band attributed until now to the mastoido- humeralis. These are the considerations which induce us to make this modification : 1, This band is not distinct from the cuticularis of the neck; a separation between the two muscles can only be artificially obtained. 2, In dissecting this band with care, we can see that its fibres, like those of the cuticularis, are not mixed with those of the mastoido-humeralis (superficial portion); they pass along the external surface of that muscle, to which they intimately adhere, it is true, but they can easily be separated, aid are continuous with the aponeurosis of the first, MUSCLES OF THE TRUNK. 197 Man, and the trachelo-acromialis peculiar to quadruped mammals'—G. Cuvier, ‘Lecons d' Anatomie Comparée,’ 2nd edition. (This is the muscle which Percivall names the levator humert. ‘The above is the designation given to it by Girard and Chauveau, Leyh gives it the same designation as Bourgelat.) Extent—Situation—Direction—Composition—This muscle extends from the summit of the head to the inferior part of the arm, and is applied to the scapulo-humeral angle at the side of the neck, in an oblique direction down- wards and backwards. It is composed of two portions lying longitudi- nally and somewhat intimately united, and distinguished into anterior and postertor. Form—Structure—Attachments.—A. The anterior or superficial portion (Fig. 106, 6) constitutes a long fleshy band, which appears to be united, by its anterior border, to the cuticular muscle of the neck. Its superior extremity, thin and wide, is attached to the mastoid process and crest by an aponeurosis (Fig. 102, 7), which is united, in froni, to the tendon of the sterno-maxillaris by a very thin cellulo-aponeurotic fascia. Its inferior ex- tremity, thicker than the superior, is inserted by means of a very short aponeurosis into the humerus, on the salient border descending from the deltoid imprint, and which limits, in front, the furrow of torsion on the body of that bone (Fig. 102, 7). B. The posterior or deep portion (Fig. 102, 9) is 9 second muscular band, shorter and stronger than the preceding. It is attached, above, to the transverse processes of the first four cervical vertebrae by as many fleshy bands (Fig. 102, 8’), which cover the superficial portion. The upper digitation, given off to tue atlas. is united to the tendon common to the small complexus and splenius (Figs. 105, 9; 106, 9', 10,11). The inferior extremity of this portion of the muscle widens on the scapulo-humeral angle, which it ‘envelops in becoming closely united to the anterior portion, terminating with it on the humerus. An aponeurosis, which is confounded with that of the trapezius, and sends off a septum into the interstice between the two portions of the long abductor of the arm, concurs to fix this extremity by spreading over the muscles of the arm. Relations.—It is covered, near its mastoid insertién, by the.parotid gland and the cervico-auricularis muscles; for the remainder of its extent, by the aponeurosis of the cuticularis colli, from which it isjseparated by a thin fascia continuous with that which extends over the trapezius. It covers the splenius, the small complexus, the oblique muscles of the head, subscapulo- hyoideus (to which it adheres intimately), the digastricus, long flexor of the head. the angularis, scalenus, small pectoral, supra- and infraspinatus, the long abductor of the arm, and the coraco-radialis. i 1 At first sight we might hesitate to admit that this muscle is formed of such varied and complicated elements as are enumerated above. Nevertheless, it is a scientific fact; and we will give a demonstration, as simple as it is clear, that such is the case—the idea we owe to J. F. Meckel. If we take the Dog, for example, and suppose it to be possessed of a clavicle extending from the anterior extremity of the sternum to the acromion; this clavicle would cut, transversely, the inferior portion of the mastoido- humeralis, which would thus be divided into two portions, a superior and an inferior. The first, extending from the clavicle to the mastoid process, on this side, and on the other to the mastoid crest, as well as to the cervical ligament, where it is confounded with the trapezius, would exactly represent the elavicular portion of the latter muscle, and the cleido-mastoideus. With resyect to the inferior portion, it perfectly resembles, by its attachments, the clavicular portion of the deltoid. But, on the contrary, if we suppose Man deprived of a clavicle, the three muscular fasciculi indicated, in becoming con- founded with each other, would form the mastoido-humeralis of the Dog, minus the posterior portion, or the trachelo-acromialis, which is not represented in Man. + 198 THE MUSCLES. Action.—When the superior is the fixed point, it carries the entire anterior limb forward. This muscle, therefore, plays a very Important part in locomotion; as it is called into action when the animal raises the fore-limb in getting over the ground. If the fixed point éf the muscle is the limb, it inclines the head and neck to one side. 3. Sterno-mawillaris. (Figs. 102, 10; 114, 4.) Symonym.—The sterno-mastoideus of Man and a large number of the lower animals. Form—Structure—Situation—Direction—Attachments.—A long narrow muscle, almost entirely fleshy, and terminated at its upper extremity by a flat- tened tendon; situated in front of the neck, beneath the cuticularis, and parallel to the anterior border of the superficial portion of the mastoido- humeralis, from which it is separated by a space that lodges the jugular vein ; attached, inferiorly, to the cariniform cartilage of the sternum—fixed insertion ; and superiorly—movable insertion—to the curved portion of the posterior border of the maxillary bone by its terminal tendon. Relations.—The muscle is covered by the cuticularis colli, and the parotid gland. It covers the trachea, the subscapulo-hyoideus, sterno- hyoideus, sterno-thyroideus, and the maxillary gland. Its external border, parallel to the anterior border of the mastoido-humeralis, forms with it a longitudinal depression termed the jugular furrow, because it lodges the vein of that name. Its inner border is intimately united, in its lower third, to that of the opposite muscle. Action.—It directly flexes the head, when acting in concert with its congener; but alone it turns it to one side. Lafosse and Rigot have wrongly eonsidered this muscle as a depressor of the lower jaw. Bourgelat has correctly stated that it cannot move this jaw independently. (Percivall says that the pair will assist in opening the mouth; and Leyh asserts that when the mouth is closed, each muscle will act as a flexor to the head.) - 4, Sterno-hyoideus.—5. Sterno-thyroideus. (Fig. 114, 6, 7.) i (Synonym.—The sterno-thyro-hyoideus of Percivall.) Form—Structure—Situation—Attachments——Small, ribbon-shaped, long, and slender muscles ; digastric ; situated in front of the trachea ; confounded at their inferior extremity and united to those of the opposite side, so as to form a single fasciculus which is attached to the cariniform cartilage of the sternum—fiwed insertion ; isolated from each other above the tendon which makes them digastric, and terminating by their superior extremity-—movable insertion : the first, on the inferior surface of the body of the hyoid bone in common with the subscapulo-hyoideus ; the second, on the posterior border of the thyroid cartilage. Relations.—Covered by the sterno-maxillaris and the cuticularis muscle, they cover the anterior face of the trachea. Aclion.—Depressors of the hyoid bone and larynx, 6. Omo-hyoideus or Subscapulo-hyoideus. (Figs. 102,11; 114, 5.) Synonyms.—Hyoideus—Bourgelat. (Subscapulo-hyoideus—Perctvall.) Form—Structure —Situation—Direction—This muscle forms a thin and wide band, almost entirely fleshy, oblique forwards and upwards, extending from the scapulo-humeral angle to the intermaxillary space, and applied to sthe side of the trachea, whose direction it slightly crosses. MUSCLES OF THE TRUNK. 199 Attachments.—It derives its fixed insertion from the inner surface of the subscapularis, by an aponeurosis which is detached from that covering the latter muscle. Its movable insertion is into the body of the hyoid bone, in becoming confounded with the sterno-hyoideus, and in being intimately united to the muscles of the opposite side. Relation—Outwardly, with the «subscapularis, supraspinatus, small pectoral, mastoido-humeralis—which closely adheres to it, the jugular vein, the sterno-maxillaris, and the cuticularis. Inwardly, with the scalenus, the large anterior straight muscle of the head, the main trunk of the carotid artery and the nerves accompanying it, the trachea, thyroid gland, and the inferior face of the larynx. The jugular vein is entirely separated from the carotid artery by this muscle in the upper half of the neck. Action,—It is a depressor of the hyvid bone and its appendages. 7. Great Anterior Straight Muscle of the Head. (Figs. 104 and 105, 10 5 106, 13.) Synonyms.—Long flexor of the head—Bourgelat. Trachelo-suboccipitalis— Girard. (Rectus capitis anticis major—Percivall. Trachelo-occipitalis—Leyh.) Form—Structure—Situation —Direction.— A long, flat muscle, fascicu- lated in its posterior half, terminated in a tendinous cone at its anterior. extremity, and passing along the first cervical vertebre in front. Attachments.—Behind, to the transverse processes of the third, fourth, and fifth cervical vertebre by as many fleshy digitations, the most inferior of which are the longest—fixed insertion. In front, into the imprints on the body of the sphenoid bone and the basilar process, by its terminal tendon— movable insertion. Relations—Outwardly, with the mastoido-humeralis, the subscapulo- hyoideus, and the small anterior straight muscle. Inwardly, with the long muscle of the neck and the muscle of the opposite side. In front, with the common carotid, the nerves accompanying this artery, and the guttural pouch, which lines it near its movable insertion. Behind, with the great oblique muscle of the head and the occipito-atloid articulation. Action.—It either directly flexes the head or carries it to one side, according as it acts alone or with its fellow of the opposite side. 8. Small Anterior Straight Muscle of the Head. “Bynonyms.—Flexor capitis brevis—Bourgelat. — Atlvido-suboccipitalis— Girard. (Rectus capitis anticus minor—Percivall. Atloido-oceipitalis inferior—Leyh.) A small, entirely fleshy, prismatic fasciculus, lying to the external side of the preceding muscle; attached, posteriorly, to the inferior face of the body of the atlas ; in front, to the body of the sphenoid bone and the basilar process, beside the great anterior straight muscle. It is covered by the guttural pouch, and covers the occipito-atloid articulation. It concurs in flexing the head. 9. Small Lateral Straight Muscle. Synonyms.—Flexor capitis parvus—Bourgelat. Atloido-styloideus—Girard, (Obli- quus capitis anticus—Percivall. The rectus capitis lateralis of Man.) Yet smaller than the preceding, and prismatic and entirely fleshy, like it this muscle lies on the side of the occipito-atloid articulation ; it is attached to the atlas, outside the small anterior straight muscle—fixed insertion ; and to the inner face of the styloid process of the occipital bone—movable insertion. It is the congener of the two anterior straight muscles of the head. 200 THE MUSCLES, 10. Scalenus. (Figs. 104, 105, 106.) Synonyms.—Costo-tracheleus—Girard. (Scalenus anticus and posticus of Man.) Sttuation — Direction—Composition.—Deeply situated at the inferior part of the neck, in an oblique direction downwards and backwards, this muscle comprises two portions of unequal dimensions, placed one above another. . Form—Structure—Attachments.— A. The superior portion (scalenus posti- cus of Man), the smallest, is composed of three or four fleshy fasciculi, attached by their extremities to the transverse processes of the last three or four cervical vertebre. The last terminates at the superior extremity of the first rib. B. The inferior (scalenus anticus of Man), the most considerable, is flattened on both sides, thick and wide posteriorly, thin and narrow anteriorly, and is composed almost entirely of fleshy fibres which are longest as they are inferior. It is attached: 1, To the transverse processes of the last four cervical vertebre by short fasciculi scarcely distinct from one another, the first of which is crossed by the last digitation of the great anterior straight muscle; 2, To the anterior border and external face of the first rib, where all its fibres end. Relations.—The scalenus responds: by its external face, to the sub- scapulo-hyoideus, mastoido-humeralis, and the sterno-prescapularis; by its internal face, to the longus colli, trachea, common carotid artery and its accompanying nerves, and—on the left side only—to the cesophagus; by its inferior border, to the jugular.vein. The two portions of the scalenus are separated from one another, in front of the first rib, by an interspace traversed Ly the nerves of the brachial pléxus. Action.— When the first rib is the fixed point, this muscle either directly flexes the neck or inclines it to one side. When the neck is the fixed point, it draws forward the first rib and fixes it in this position during the dilatation of the chest, in order to aid the inspiratory action of the external intercostal muscles. € 11. Long Muscle of the Neck. Synonyms.—Flexor longus colli—Bourgelat. Subdorso-atloideus—Girard. (Longus collig- Percival, Dorso-atloideus—Leyh.) / Situation—Composition—A single and considerable muscle, immediately covering the inferior aspect of all the cervical and the first six dorsal vertebrae, and composed of two lateral portions which are united on the median line, and constitute, in certain animals, two distinct muscles. Structure—Attachments.—Kach lateral portion of the longus colli is composed of a succession of very tendinous fasciculi. The most posterior of these is attached to the inferior face of the bodies of the first six dorsal vertebre, and proceeds directly forward to reach the inferior tubercle of the sixth cervical vertebra, into which it is inserted by a strong tendon. The other fasciculi, less considerable, and confounded outwardly with the inter- transversales of the neck, are carried from one cervical vertebra to another, and are directed forwards, upwards, and inwards, in converging towards those of the opposite side. They are attached successively : outwardly, to the transverse processes of the last six cervical vertebra; inwardly, to the inferior ridge on the bodies of the first six. The most anterior fasciculus passes to the inferior tubercle of the atlas, into which it is inserted by a MUSCLES OF THE TRUNE. 201 tendon common to it and the fasciculus of the opposite side, and which receives the most superficial fibres of the three or four preceding fasciculi. Relations——Above and behind, with the vertebree which it covers, as well as their intervertebral discs; below and in front, with the trachea and cesophagus, and the vessels and nerves accompanying these two tubes; on the sides, with the great anterior straight and the scalenus muscles in its cervical portion, and in its intrathoracic portion, with the pleurw, and important vessels and nerves. Action.—It flexes the whole neck, and the cervical vertebra on one another. DIFFERENTIAL CHARACTERS OF THE MUSOLES OF THE CERVICAL REGION IN OTHER THAN SOLIPED ANIMALS, A. Superior Cervical Region. 1. Buminants.—In the Oz, the angularis arises by six digitations from all the cervical vertebrae except the first; the eg is little developed, and is not attached to either the third or fourth cervical vertebra. 2. Pic.—The muscles of the superior cervical region in this animal are generally very developed. The rhomboideus is divided into two fleshy bodies, one of which proceeds to the occipital protuberance, and the other to the rudimentary cervical ligament and the first dorsal vertebre. The angularis is attached, as in Ruminants, to the six cervical vertebre ; sometimes it even shows a digitation that descends to the atlas. The splenius only terminates anteriorly by three fleshy bodies; but they are voluminous, and are inserted, one into the atlas, another into the mastoid crest, and the third into the occipital protuberance. In the great complexus, the two portions are completely separated from each other, except at their upper extremity, by the interspace lodging the superior cervical artery. The aponeurosis attaching the muscle to the spinous processes of the first dorsal vertebrae is not confounded with that of the splenius or the small anterior serrated respiratory muscle. The atloidean fleshy body of the small complexus is scarcely distinct from the superior branch of the ilio-spinalis and the intertransversales. Lastly, it is difficult to distinguish the small posterior straight muscle from the deep fasciculus of the great straight muscle. 3. Garnivora—In these animals the muscles of the superior cervical region are nearly all voluminous, as in the Pig. The rhomboideus is bifid at its origin, and its anterior branch arises from the mastqid crest. The angularis is also attached to the last six cervical vertebre. Very thick and bread, the splenius only passes to the atlas and ee crest. The oblique and straight posterior muscles of the head are also remarkably thick. B. Inferior Cervical or Trachelian Region. 1, Rummwants—In the Ox and Sheep, the disposition of the cuticularis colli offers 2, very considerable difference from that observed in Solipeds. The fleshy portion is absent, or appears to be absent, in the cervical region; the anterior muscles of the neck are only covered by a thin fascia developed on the sides of the neck. When this fascia reaches the face, it becomes continuous with the fleshy fibres; a fasciculus of these fibres comports itself as in the Horse, and goes to join the alveo-labialis; another is intercrossed in the maxillary space by the analogous fasciculus of the opposite side. The cervical cuticularis muscle of the Ox is also distinguished by an extremely remarkable peculiarity which it is necessary to allude to here :—The fleshy cervical band, altogether absent in the Sheep, is not so in the Ox; we have found it forming, beneath the above-mentioned aponeurotic.fascia, the long, thick strip which has been described by veterinary anatomists a3 the analogue of the sterno-maxillaris in the Horse. This strip is attached, like the muscular band which represents it in Solipeds, to the anterior point of the sternum. But its fibres, instead of being spread outwards over the mastoido- humeralis, ascend, perfectly isolated from that muscle, to the posterior border of the mavxillaris. There it terminates (Fig. 112, 18) by a flattened tendon which, after reaching the anterior border of the masseter, is confounded with the apoueurosis of that muscle, and sends some fibrous bands over the muscles of the face. The two portions of the mastoido-humeralis of Ruminantsare better defined, and more oblique on one another, than in the Horse, The superyicial portion receives on its inner 202 THE MUSCLES. face a small, bright-red, funicular fasciculus, which proceeds from the cartilage of the first rib, and which Meckel is inclined to consider as the vestige of the subclavius. It is divided, superiorly, into two branches: one, the clavicular portion of the trapezius, very wide, passes to the mastoid process, the curved line of the occipital bone, and to the cervical ligament, in becoming confounded with the trapezium (Fig. 112, 22); the other, the eleido-mastoideus, terminates in a tendon that joins the sterno-suboccipitalis, and is inserted into the basilar process, after receiving the fibres of the long flexor of the head (Fig. 112, 21), The upper extremity of the deep portion of the mastoido-humeralis is inserted into the atlas by a flattened tendon alone, which is quite distinct from the atloid insertions of the splenius and the small complexus, : In the Sheep and Goat, the costal band that joins the superficial portion is absent. "The latter is divided at its inferior extremity into two branches, between which pass the biceps. The upper branch passes to the epitrochlea, The sterno-maxillary muscle, instead of being inserted into the inferior maxilla, is united to the suboccipital branch of the mastoido-humeralis, to be attached to the basilar process. At another time we will discuss the determination of this muscle, and that of the fleshy band here considered as belonging to the first (see Spinal Nerve). a Ze sterno-hyoid and sterno-thyroid muscles are thicker than in the Horse, and not gastric. The subscapulo-hyoideus of Ruminants ig but slightly developed, and might be termed the trachelo-hyoideus ; as it proceeds to the tiansverse process of the third or fourth cervical vertebra. In its passage beneath the basilar branch of the mastoido-humeralis on Seas (sterno-maxillaris), it contracts adhesions with the fibres of these wo muscles. The great anterior straight muscle of the head descends to the sixth cervical vertebra Tts cervical insertions are covered by a very strong muscular fasciculus, which is annexed to it. Like it, this fasciculus leaves the sixth cervical vertebra, and’ is attached to the transverse processes of the four vertebra preceding the last, by becoming confounded with the intertransversales, and finally terminating at the tracheal process of the atlas by fleshy and aponeurotic fibres. This muscular fasciculus singularly strengthens the neck when it is inclined to one side. In consequence of its attachments, it might be named the trachelo-atloideus (Fig. 112, 24). Lastly, in Ruminants the superior scalenus is very developed, being a flattened band which, gradually expanding, is prolonged to the surface of the serratus magnus. 2. Pra.—In this animal, the cuticularis colli is in two portions: an inferior, which comes from the point of the sternum ; and a superior, from the external scapular region, They unite in front, and are prolgmged in common on th 1 f a tracting adhesions with the external + of th ee pene alagpect of the body and the branches of the maxillary The other muscles of the inferior cervical regi : ik i Of the two portions of the Ca nacaat Me oe ee genre extremity. The posterior branch, the clavicular ‘portion of the tr nl att a e the side of the occipital protuberance; the anterior branch, th ces eietias He beneath the external auditory hiatus, to the crest that re lace: th nen ere te enn = pings is attached above to the atlas only. ab iaat oy es cial n the Pig, the sterno-maxillaris exact. y i i tendon passes directly to the mastoid Rae a Cae a a - ee a aca is double; the supplementary branch going to the inferior face The subscapulo-hyoideus and great anteri i piace lean WY acid hha! Sul ia ag Sas muscle of the head, resemble those ad ; : is scarcely distinct from the small oblique. he supertor scalenus extends to the third rib, The two lateral porti f the l re Gt the neck are separate, and form two distinct muscles ies ae _ 3 ARNIVORA.—In the Dog, each cuticularis i in i i Pig. The fibres from the beat are directed in a ae eee aa a eee ciety maxillary space, and the parotid gland, where they form th otters ci ae The portion coming from the external scapular region i nee : aged epee pat the st ates ene of the neck, the parotid gland, ee cecae un i oS ea receding, an rmi i f ‘ ‘ joi those i rik gree ese Os the face and in the submaxillary space, where its fibres he mastotdo-humeralis comports itself s i i i Helga ss is bifid snperierly ; one of sak Re eee dies velar ap feed e cleido-mastoideus ; the other into the mastoid crest a ical li i iting by aponeurosis with the trapezius— y in eae eae Pt eee portion passes from the atta’ to the ee BO Ce eer eee MUSCLES OF THE TRUNK. 203 The tendon of the sterno-mazillaris goes to the mastoid process. The sterno-hyoideus net thyroideus axe thick and not digastric, and commence from the cartilage of the first ri The Carnivora have no subscapulo-hyotdeus ; but they possess a very long scalenus, which passes to the eighth rib, and a long muscle of the neck, which tend divided into two lateral portions, : . ss a ee SPINAL REGION OF THE BACK AND LOINS. This offers for study eight pairs of muscles, nearly all of which have their insertions extended over the dorso-lumbar spine, and are disposed in several layers on each side of this long multifidious crest. These muscles are, enumerating them according to their order of superposition: 1, The trapezius; 2, Great dorsal ; 3, Small anterior respiratory serratus ; 4, Small posterior serratus ; 5, Ilio-spinalis (longissimus dorsi); 6, Common intercostal ; 7, Transversales of the back and loins (semispinalis dorsi and lwmborum). Preparation.—1. Place the animal in the second position. 2. Remove the skin with the panniculus and the mass of olecranian muscles, to show, in a first operation, the trapezius and great dorsal muscles (Fig. 102). 3. In a second operation, remove the entire fore-limb, wita the great dorsal muscle, whose mode of termination may then be studied ; then prepare the two small serrated muscles. 4. Remove these two muscles, as well as the angularis of the scapula and the splenius, to expose the common intercostal and ilio-spinalis (Fig. 106). The superior branch of the latter remaining covered by the great complexus, excise this muscle, leaving only its insertions into the transverse processes of the dorsal vertebre, to show how tiey are fixed between the two branches of the ilio-spinalis (longissimus dorsi). 5. Dissect the transversales (semispinalis) by removing the ilio-spinalis and the internal angle of the ilium. 1. Trapezius. (Fig. 102, 1, 3.) Synonym.—Dorso- and cervico-acromialis—Girard. Situation—Form—Structure-—This is a superficial membranous muscle, situated on the sides of the neck and withers, Its shape is that of a triangle whose base is upwards. It is aponeurotic, rt its upper border and in its centre, which allows it to be distinguished, especially in emaciated subjects, into a cervical and a dorsal portion. The fleshy fibres of the first are directed downwards and backwards; those of the second are oblique forwards. Attachments —By its superior aponeurosis, it is fixed to the cervical cord and to the summits of the teammrexse-processes of the first dorsal vertebra, ¢ where it adheres to the external face of the great dorsal muscle. By~ its central aponeurosis and that of its summit, it is attached to the tuberosity _, of the @keemamiaar spine and the external scapular aponeurosis. ©) Relations.—This muscle is covered by two aponeurotic planes, whose « fibres cross its own at aright angle. Inwardly, it responds to the rhom- boideus, splenius, angularis, sterno-prescapularis, the supra- and infra- spinatus, and the great dorsal. ‘Action.—It raises the shoulder, and carries it forward or backward, according as one or other of its muscular portions contract. 2. Great Dorsal. (Fig. 102, 2.) ~ synonyms.—Dorso-humeralis— Girard. (Latissimus dorsi—Pereivall.) Form—Situation—Structure—Attachments—A very broad triangular muscle, extended over the loins, back, and side of the thorax, and formed of . an aponeurotic and a muscular portion. ; The aponeurosis is attached, by its superior border, to the summits 204 THE MUSCLES, of the spinous processes of all the lumbar and the last fourteen or fifteen dorsal vertebrae—fived insertion of the muscle, : : The fibres of the fleshy portion are detached from the inferior border of the aponeurosis, at the twelth or thirteenth ribs, to the cartilage of the scapula. They are directed forwards and downwards, and all converge into a flat tendon which is inserted into the internal tuberosity on the body of the humerus—movable insertion. This tendon is remarkable, at its termination, for being placed at the external face of the teres magmis or adductor of the arm, from which it receives fibres, and between it and the long extensor of the fore-arm ; it then turns inwards, on the inferior extremity of the first, in such a manner that this extremity is comprised Fig. 105. MUSCLES OF THE SPINAL REGION OF THE NECK, BACK, AND LOINS, MIDDLE LAYER; AND OF THE COSTAL AND ABDOMINAL REGION, SUPERFICIAL LAYER. 1, 2, Rhomboideus ; 3, Angular muscle of the scapula; 4, Splenius; 5, Its mastoid aponeurosis ; 6, Mastoid portion of the small complexus; 7, Its tendon; 8, Cer- vical insertions of the mastoido-humeralis; 9, Atloidean tendon common to the mastoido-humeralis, splenius, and small complexus; 10, Great anterior straight muscle of the head; 11, Inferior scalenus; 12, Superior scalenus; 13, Small anterior serratus; 14, Posterior ditto; 15, Great serratus; 16, Transverse muscle of the ribs; 17, One of the external intercostals; 18, Great oblique - muscle of the abdomen; 20, Straight muscle of the abdomen; 21, Stylo-maxil- lary portion of the digastric muscle. within a duplicature of the membranous tendon of the latissimus dorsi (Fig. 121). Relations—This muscle is covered by the skin, panniculus carnosus, dorsal portion of the trapezius, and the mass of olecranian muscles. It covers the infraspinatus; the cartilage of the scapula; the rhomboideus; the small anterior and posterior serrated muscles, whose aponeurosis is directly joined to its own; the ilio-spinalis; the principal gluteal ; a portion of the external surface of the last ribs, to which its aponeurosis strongly adheres; as well as the corresponding external intercostals, and the great serrated muscle. Between the last rib and the external angle of the ilium, MUSCLES OF THE TRUNK. 205 the aponeurosis unites with the small oblique, but more particularly with the great oblique, muscle of the abdomen ; it is prolonged, posteriorly, on the muscles of the croup to constitute the gluteal aponeurosis. Action.—It carries the arm backwards and upwards; and it may, cecording to & great number of authors, serve as an auxiliary in inspiration when its fixed point is the humerus. According to others, but in whose opinion we do not share, it is an expiratory muscle. 3. Small Anterior Serrated Muscle. (Fig. 105, 18.) Synonyms.—Dorso-costalis—Girard, Anterior portion of the long serrated muscle —Bourgelat. (Superficialis costarum—Percivall. Anterior serrated muscle of Leyh. Serratus posticus superior of Man.) Form—Situation.—This is a flat, thin, and quadrilateral muscle, situated beneath the rhomboideus and the great dorsal muscle. Structure.—It is composed of an aponeurotic and a fleshy portion. The first is confounded, in front, with the aponeurosis of the splenius, and is insinuated, behind, underneath that of the posterior small serratus, with which it soon becomes united. Its inferior border gives origin to the muscular portion, a little above the interval which separates the common intercostal and the ilio-spinalis. Narrow and elongated antero-posteriorly, the muscular portion is composed of bright-red fibres directed obliquely backwards and downwards, and which form at the inferior border irregular, and sometimes but faintly marked, festoons. Aitachments.—It takes its fixed insertion, by the superior border of its aponeurosis, from the summits of the antericr dorsal spines, with the exception of the first, to the thirteenth inclusive. The movable insertion takes place on the external surface and anterior border of the nine ribs succeeding the fourth, by means of the digitations of the fleshy portion. This muscle is also attached to the external surface of these ribs by a short fibrous band, which is detached from the internal face of the aponeurosis, near its inferior border, and penetrates the space between the ilio-spinalis and the common intercostal muscle. Relations —Outwards, with the rhomboideus, great serratus, great dorsal, and the posterior small serratus, which covers its three last festoons ; inwards, with the ilio-spinalis, the common intercostal, and the external intercostals. Action.—This is an inspiratory muscle, and it also serves as a check to the deep spinal muscles. 4, Small Posterior Serrated Muscle. (Fig 105, 14.) ‘Synonyms.—Lumbo-costalis— Girard. Posterior portion of the long serrated muscle —Bourgelat. (Superficialis costarum—Pereivall. The posterior serrated muscle of Leyh, The serratus posticus inferior of Map.) Situation Situated behind the preceding, which it follows, and present- ing the same form and arrangement, this muscle also offers the following particular features for study : aoe 1. Structure—Its muscular portion, which is thicker and of a deep-red colour, is cut into nine well-defined digitations.' The fibres which compose it run in an almost vertical direction. 9, Attachments.—Its aponeurosis, closely united to that of the great dorsal muscle, which covers it, is attached to the spinous processes of the dorsal 1 It frequently happens that only eight digitations are found. 206 THE MUSCLES. vertebre after the tenth, and to some lumbar vertebre. Its digitations are fixed to the posterior border and external face of the nine last ribs. 3. Relations. —Outwards, with the great dorsal; inwards, with the small anterior serratus, the ilio-spinalis, common intercostal, and the external intercostals. Some of its posterior digitations are partly con- cealed by those of the great oblique muscle of the abdomen; the last, indeed, is entirely covered by that muscle. ; ; 4, Action.—This is an expiratory muscle, in consequence of its drawing the ribs backwards and upwards. 5. The Ilio-spinalis Muscle. (Fig. 106.) Synonyms.—It represents the long dorsal, short transversal, and long spinous of Bourgelat. Cuvier and others have described it as consisting generally, in mammalia, of five particular muscles, designated as longissimus dorsi, transversalis cervicis, semi- spinalis dorsi, and semispinalis colli. It corresponds to the longissimus dorsi, and trans- versalis cervicis of Man. (Percivall designates this important muscle the longissimus-dorsi—the name given to its analogue in Man. By Girard, Leyh, and Chauveau, it is styled the éléo-spinalis.) Extent—Situation.—This, the most powerful and complex of all the muscles in the body, extends along the dorso-lumbar spine, above the costal arches, from the anterior border of the ilium to the middle of the cervical stalk. Form.—tlt is elongated from before to behind, and flattened above and below in its posterior half, which represents the common mass in Man; this mass is prismatic in form, thick inwards, and thin outwards. Anteriorly, it is flat on both sides, and bifurcates into two voluminous branches, a superior and inferior, between which pass the insertions of the complexus to be fixed into the transverse processes of the first dorsal vertebree. Attachments.—1, Upon the lumbar border, the external anglo and internal surface of the ilium, the sacro-iliac ligament, and the sacrum; 2, To the spinous processes of all the lumbar and dorsal, and last four cervical vertebra ; 3, To the articular tubercles of the lumbar vertebre and the transverse processes of all the dorsal, and the last four cervical vertebra ; 4, To the costiform processes of the lumbar vertebra, and the external surface of the fifteen or sixteen last ribs. : Structure.—If this muscle is examined posteriorly, in the part which forms the common mass, it will be found to be composed of very compact fleshy fibres, covered in common by a thick aponeurosis. These fibres commence at the posterior.extremity of the muscle, and all proceed forward, stopping to take successive insertions on the various bony eminences in its track, and forming three different orders of fasciculi, which are more or less tendinous at their anterior or terminal extremity. These fasciculi are internal and superficial, internal and deep, and external, The internal and superficial, or spinal fasciculi, pass to the summits of the spinous processes already noticed when speaking of the attachments. These fasciculi are little, if at all distinct posteriorly ; but they become more so anteriorly. About the sixth dorsal vertebra, they separate from the other fasciculi to form the superior branch of the muscle (Fig. 106, 3). The internal and profound, or transverse fasciculi, are those which attach the muscle to the articular tubercles of the lumbar vertebree and transverse processes of the back and neck. They are well detached from each other, cven posteriorly, and are very tendinous. Anteriorly, they pass into the inferior branch of the ilio-spinalis, which they, in common with Uy A Pnsias OF THE TRUNK, 207 Fig. 106. 1, 2, 3, 4, Ilio-spinalis; 5, Com- mon intercostal; 6, Principal portion of the great complexus ; 7, Anterior portion of the same ; 8, Mastoid fasciculus of the small complexus; 8’, Its ten- don; 9, Atloid fasciculus of that muscle; 9’, Its tendon; 10, At- loid insertion of the splenius turned forward; 11, Ditto of the mastoido-humeralis; 12, Intertransversales of the neck; 13, Long flexor of the head; 14, Inferior scalenus; 15, Superior scalenus; 16, Internal inter- costals; 17, Dependent fasci- culus of the small oblique, form- ing the retractor of the last. rib, according to German anatom- ists; 17’, Small oblique muscle of the abdomen; 18, Transverse muscle of the abdomen, / DEEP MUSCLES OF THE SPINAL REGION OF THE NECK, BACK, AND LOINS, AND THE COSTAL AND INFERIOR ABDOMINAL REGIONS, = Some ene gS wie a ae 208 THE MUSCLER® a the external fasciculi, go to form. From profound, they now become superficial ; and they are seen springing up betwéen the others, which appear to separate to allow them to pass (Fig. 106, 4, 4)... ; The external, or costal fasciculi, turn a little outwards to reach the ribs and costiform processes of the lumbar region ; they are no} very apparent in this direction (Fig 106, 2, 2). 4 It will be easily understood that all these fasciculi do no! come from the common mass, which would be expended long before its termination at the neck, in consequence of the successive emissions of the fasciculi composing it. To prevent this expenditure, there are continually added to it numerous reinforcing bundles of fibres, which arise either|from its aponeurotic envelope, or from the bones on which the primary’ fasciculi terminate, and comport themselves absolutely like these, which {hey are charged to continue to the neck. Relations.—The ilio-spinalis is covered by the pyramidal point} of the « principal gluteal muscle, which it receives in a particular excavation,‘and by the: aponeurosis of the great dorsal and the small serrated muscles. It covers the intertransyersales of the lumbar region, the transversales of the back and loins, the supercostals (levatores costarwm) and the external,” intercostals. Outwards, it is bordered by the common intercostal. ‘, The superior branch is covered by the great complexus and the t versales colli. Inwardly, it responds to the cervical ligament and the anal gous branch of the opposite muscle. The inferior branch responds, outwardly, to the angularis of the scapula. it covers some intertransversales colli, and the aponeurotic digitations whic: attach the great complexus to the transverse processes of the first dorsal vertebre. From these digitations it even detaches a number of musculay fasciculi, which go to strengthen this branch of the ilio-spinalis. Action.—It is a powerful extensor of the vertebral column, which, wh it acts singly, it inclines to one side. It may also take part in expiration. é 6. Common Intercostal Muscle. (Fig. 106, 5.) Synonyms.—Trachelo-costalis— Girard. The sacro-lumbulis of Man. (Transversalis costarum—Percivall.) ody Form—Situation.—A long, narrow, and thin muscle—particularly at its extremities—situated along the external border of the preceding muscle, with which it is confounded behind the last rib. ee Structure—Attachments.—This muscle, whose structure has been com plicated at will by so many anatomists, is yet extremely simple. It is formed of a series of fasciculi, directed obliquely forwards, downwards, and out- wards, tendinous at their extremities, and originating and terminating successively on the external surface of the ribs. The most posterior leave the external border and inferior face of the common mass. The tendinous digitation of the anterior fasciculus is inserted into the transverse process of hes last cervical vertebra, in common with the inferior branch of the ilio- spinalis. ‘ Felations.—Outwards, with the great and small serratus: inwards, with the external intercostals, , ie, re depresses the ribs, and may extend the dorsal portion of the MUSCLES OF THE TRUNK. - 209 7. Transverse Spinous Muscle of the Back and Loins. (Fig. 106, 3.) Synonyms.—Transverso-spinous—Girard. Dorso-lumbar portion of the semispinali of Man. (The spinalis and semispinalis dorsi—Percivall.) as ene Situation—Extent.—This is a very long muscle, directly applied to the supersacral and dorso-lumbar spine, and continuous, in front, with the transversales colli; these two muscles, therefore, measure nearly the whole length-of the spine. Structure.—It is formed of an assemblage of short fasciculi, which are flattened on both sides, tendinous at their extremities, directed obliquely forwards and downwards, and a little inwards, thus crossing at a right angle the spinous processes they cover. Attachments—These fasciculi are attached, below, to the lateral lip of the sacrum, the articular tubercles of the lumbar vertebra, and the trans- verse processes of the dorsal vertebre—origin. They are fixed, above, to the spinous processes of the sacral, lumbar, and dorsal vertebra, and into that of the last cervical vertebra—termination. It is to be remarked that they do not attain the summits of these spinous processes in the first half of the dorsal region. Relations.—Outwards, with the lateral sacro-coccygeal and ilio-spinalis muscles, which are confounded with it near its posterior extremity ; inwards, with the sacral spine and the spines of the lumbar and dorsal vertebre, and with the interspinous ligaments of these three regions. Action.—It is an extensor of the spine. DIFFERENTIAL CHARACTERS OF THE MUSCLES IN THE SPINAL REGION OF THE BACK AND LOINS IN OTHER THAN SOLIPED ANIMALS. 1. Ruminants.—In the Ox, Sheep, and Goat, the trapezius is thick and very broad. The anterior small serrated muscle is inserted, by its last digitation, into the ninth rib, The posterior serrated is fixed into the four last ribs. 2. Pia.—Its trapezius is well developed. The great dorsal is voluminous, and ig attached to the surface of the ribs, which it covers by digitations from its fleshy portion. It is fixed near the small trochanter to the lip of the bicipital groove. The inferior branch of the ilio-spinalis of this animal is easily divided into two portions, traces of which are found in the Horse: one is formed by the costal fasciculi, the other by the transversal fasciculi. The latter constitutes the muscle to which Bourgelat has given the name of short transversal. . 3. Carnivora.—Several of the spinal muscles in the Dog resemble those of the Pig; such are the trapezium, the great dorsal, and the ilio-spinalis. In animals of this group, it is remarked that the anterior serrated is very thick and very developed, and that it is attached to the eight ribs succeeding the second by as many well-marked festoons. The posterior has only three digitations, which are attached to the three last ribs. The common intercostal exactly resembles the sacro-lumbalis of Man ; behind the last rib, it constitutes a thick fleshy body, separated by a fissure from the ilio-spinalis, with which it is attached to the coxa. Lastly, the transverse spinal muscle of the hack and loins is very strong in the lumbar region, and is prolonged on the coccygeal vertebrz. ) (According to Leyh, the interspinales muscles are absent in the Horse and Ruminants; they are found in the Pig between the spinous processes of the dorsal and lumbar vertebr, and in Carnivora between the spinous processes of the cervical vertebrae.) COMPARISON OF THE MUSCLES OF THE BACK AND NECK IN MAN WITH THE ANALOGOUS MUSCLES IN THE DOMESTICATED ANIMALS, It is usual, in human anatomy, to describe by the name of muscles of the back and neck those which correspond to the superior cervical region, and those of the spinal region “of the back and loins of the domesticated animals. The muscles of the inferior cervical region are described in Man as muscles of the neck, with the hyoid muscles and the scalenus. 210 THE MUSCLES. A. Muscles of the Back and Cervix. ; ; : ‘stiipnished, In the trapezius of Man, a cervical and a dorsal portion can no longer be distinguis Rove, it is atlenhed to the superior occipital curved line ; below, it is fixed to the external third of the upper border of the clavicle, and to the acromion and scapular spine, Fig. 107. FIRST, SECOND, AND PART OF THIRD LAYER OF MUSCLES OF THE BACK OF MAN} THE FIRST LAYER OCCUPIES THE RIGHT, THE SECOND THE LEFT SIDE. 1, Trapezius; 2, Tendinous portion, forming, with a corresponding part of the opposite muscle, the tendinous ellipse on the back of the neck; 3, Acromion process and spine of scapula; 4, Latissimus dorsi; 5, Deltoid; 6, Muscles of dorsum of the scapula: infraspinatus, teres minor, and teres major; 7, Obliquus externus; 8, Gluteus medius; 9, Glutei maximi; 10, Levator anguli scapule; 11, Rhomboideus minor; 12, Rhomboideus major; 13, Splenius capitis, overlying the splenius, above; 14, Splenius colli, partially seen: the common origin of the splenius is attached to the spinous processes below the origin of the rhomboideus major; 15, Vertebral aponeurosis; 16, Serratus posticus inferior; 17, Supra- spinatus; 18, Infraspinatus; 19, Teres minor; 20, Teres major; 21, Long head of triceps, passing between teres minor and maior to the arm; 22, Serratus magnus, proceeding forwards from its origin at the base of the scapula; 23, Obliquus internus abdominis. The fibres of the trapezius which are fixed into the clavicle, represent a portion of the mastoido-humeralis of quadrupeds. The great dorsal resembles that of the Dog and Pig, its fleshy portion being very developed ; itis attached to the external face of the four last ribs by muscular digitations, and tcrminates on the border of the bicipital groove, MUSCLES OF THE TRUNK. 211 _ The rhomboideus is bifid, as in the smaller quadrupeds. Less developed than in these animals, the angularis is only fixed in front to the four first cervical vertebra. In Man, the splenius is large, but by its insertions it resembles that of Solipeds. The great complexus, thick and broad above, is incompletely divided into two fleshy bodies, which are attached, superiorly, to the sides of the external occipital crest. The small compleaus is not fixed into the axis and atlas, its superior extremity passing directly to the oe brovete: ere is nothing particular to note regarding the straight posterior and oblique muscles of the head ; the differences they offer in their form are allied to the Cantons ten of the bones in this region. _Of the two small serrated muscles, that which corresponds to the anterior serrated of animals rises very high; for it is attached by an aponeurosis to the spinous processes of the three first dorsal vertebree, the seventh cervical, and the cervical ligament. There are found in Man, lying along the vertebral furrows, several muscles which represent the ¢lio-spinalis and the common intercostal of Solipeds. Thus the common masz covering the lumbar vertebre behind, is prolonged by two series of fleshy and ten- dinous fasciculi: one forms the sacro-lumbalis, which resembles the common intercostal of animals; the other, the long dorsal, represents the inferior branch of the ilio-spinalis. The superior branch of the latter is found in the transversalis colli. Lastly, there are also seen in Man w transverse spinal and intertransverse muscles, which correspond: the first, to the transverse spinous of the back and loins and transverse spinous of the neck ; the second, to the intertransversales of the loins of the domesticated species, : B. Muscles of the Neck. The mastotdo-humeralis is not present in Man, being peculiar to quadrupeds; but we should see a portion of its fasciculi in the cleido-mastoideus muscle, and in the clavicular portions of the trapezius and deltoid. The sterno-mastoideus corresponds to the sterno-mazillaris of animals: as in the Dog, it is inserted into the external face of the mastoid process and the external two-thirds of the superior occipital curved line. Below, it commences by two fasciculi—one from the sternum, the other from the clavicle. We have already alluded to this clavicular fasciculus. The sterno-hyotdeus and sterno-thyroideus are large and well developed, resembling in their disposition those of the smaller animals. It is to be noted that the sterno-hyoideus leaves the sternum, the first costal cartilage, and the internal extremity of the clavicle. The scapulo-hyoideus is digastric. The anterior great straight muscle of the head is attached to four cervical vertebra, as in Ruminants and the Pig. The anterior small straight, the lateral small straight, and the long muscle of the neck, comport themselves as in the smaller animals. The anterior sealenus is very developed, for it is attached to the six last cervical vertebrae. SUBLUMBAR, OR INFERIOR LUMBAR REGION. The muscles of this region are deeply situated at the inferior face of the lumbar vertebre and the ilium, concurring to form the roof of the abdominal cavity, and are in more or less direct contact with the viscera contained in that cavity. They are nine pairs. Three have received the generic name of psoas, and are of large volume; they are maintained by a strong aponeurosis. the iliac fascia, and are distinguished as the great psoas, iliac psoas, and small psoas. A fourth is named the square muscle of the loins (quadratus lumborum), The other five, placed between the transverse processes of the lumbar vertebra, represent, in consequence of their connection with these kind of fixed ribs, veritable intercostal muscles; these are the intertransverse muscles of the loins. Preparation.—1. Place the subject in the first position ; open the abdominal cavity by completely removing its inferior walls; empty the cavity of the viscera it contains, and excise the diaphragm, as that muscle prevents the anterior extremity of the great and small psoas muscles being seen, 2. First study the iliac fascia, its form, relations with the long abductor of the leg, its attachments, its continuity with the tendon of the small psoas, and the expansion reflected from the aponeurosis of the great abdominal oblique muscle. 3. Expose the three psoas muscles by removing the iliac fascia, the two adduc- torg of the leg, and the three adductors of the thigh. 4. Remove the psoas muscles for the dissection of the quadratus and intertransversales. 212 THE MUSCLES 1. Iiae Fascia or Lumbo-iliac Aponeurosis. (Fig. 108, a.) This is a very resisting fibrous expansion, covering the great and iliac psoas muscles. Attached, inwardly, to the tendon of the small psoas, out- wardly to the angle and external border of the ilium, this aponeurosis, as it extends forwards over the great psoas, degenerates into cellular tissue, Behind, it also becomes attenuated in accompanying the two muscles it eovers until near their insertion into the internal trochanter of the femur. Its external or inferior face receives, posteriorly, the insertion of the crural arch, and gives attachment to the long adductor of the leg; for the re- mainder of its extent, it is covered by the peritoneum. 2. Great Psoas Muscle. (Fig. 108, 1.) Synonyms.—Sublumbo-trochantineus—Girard, Psoas—Bourgelat. (Lumbo-femoral- Leyh. Psoas magnus—Percivall.) Form—Situation.—This is a long muscle, flattened above and below at its i. anterior extremity, prismatic in its middle, and terminated in a cone at its posterior extremity. It lies beneath the transverse processes of the lumbar vertebrae. Structure-—Almost entirely fleshy, this muscle is formed of fasciculi, very delicate in texture, directed backwards, and long in proportion to their superficial and deep situation. They all converge to a tendon which is enveloped by the iliac muscle, and is confounded with it. Aitachments.—The great psoas is attached: 1, By the anterior extremity of its fleshy fasciculi to the bodies of the last two dorsal and the lumbar vertebra, except the hindermost, and t6-the inferior face of the two last ribs and the transverse processes of the lumbar vertebre; 2, By its posterior tendon to the internal trochanter, in common with the psoas iliacus. Relations.—Below, with the pleura, the superior border of the diaphragm, the lumbo-iliac aponeurosis, which separates it from the peritoneum and the abdominal viscera situated in the sublumbar region; above, with the two last internal intercostals, the quadratus, and the intertransversales muscles; inwardly, with the small psoas and the internal branch of the iliac psoas; outwardly, for its posterior third, with the principal branch of the latter muscle. aes Action.—A flexor and rotator of the thigh outwards when its fixed point is the loins, this muscle also flexes the lumbar region when the thigh is a fixed point. It is, therefore, one of the agents which determine the-arching of the loins, and which operate, during exaggerated rearing or prancing, in bringing the animal into a quadrupedal position again. 3. Iliac Psoas Muscle. (Fig. 108, 8, 4.) Synonyms.—Ilio-trochantineus—Girard. (Leyh divides this muscle into two por- tions. which he describes as the great and middle ilio-femoralis, Iliacus—Percivail.) Form—Situation—Direction.—This is a very strong, thick, and prismatic muscle, incompletely divided into two unequal portions by the groove for the reception of the tendon of the great psoas: an external portion, somewhat considerable in size; and an internal, small, These two muscular portions lie at the entrance to the pelvis, on the inner face of the ilium, in an oblique direction downwards, backwards, and inwards. Structure.—It is almost entirely fleshy. The fasciculi forming it are MUSCLES OF THE TRUNK, 213 spread out in front, and collected behind, where they b i ibr and unite with the tendon of the iat aa Pree ea se Attachments.—It has its fixed insertion on the whole of the iliac surface, on the external angle of the ilium, the sacro-iliac ligament, and the ilio- Fig. 108. MUSCLES OF THE SUBLUMBAR, PATELLAR, AND INTERNAL CRURAL REGIONS 1, Psoas magnus; 1’, Its terminal tendon; 2, Psoas parvus; 3, Iliac psoas; 4, Its small internal portion; 5, Muscle of the fascia lata; 6, Anterior straight muscle of the thigh; 7, Vastus internus; 8, Long adductor of the leg; 9, Short adductor of the leg; 11, Pectineus; 12, Great adductor of the thigh; 12’, Small adductor of the thigh; 13, Semimembranosis; 14, Semitendinosis.—a, Portion of the fascia iliaca; B, Portion of the membrane reflected from the aponeurosis of the abdominal great oblique muscle, forming the crural arch (Poupart’s ligament); c, Pubic tendon of the abdominal muscles; D, Origin of the pubio-femoral ligament. pectineal crest. Its movable insertion is into the small internal trochanter, in common with the great psoas. Relations.—Above, with the ilium; below, with the iliac fascia and the long adductor of the leg; outwardly, with the muscle of the fascia lata and 17 214 THE MUSCLES. the origin of the anterior straight muscle of the thigh, from which it is separated by a space filled with fat; inwardly, with the crural vessels. It passes between the vastus internus and the pectineus, to reach the trochanter. . Actions.—It is a flexor and rotator outwards of the thigh. 4, Small Psoas Muscle. (Fig. 108, 2.) as ins—Bourgelat. Sublumbo-pubialis, or sublumbo-iliacus. ioe ePwes een eal The Tanba-thiaous of Leyh.) : Situation—Form—Structure.— Placed at the inner side of the great psoas, very much elongated, and semipenniform in shape, this muscle is terminated behind by a flattened tendon, and is composed of fleshy fibres, the longest of which are anterior. These fasciculi are all directed backwards and outwards to gain the tendon. Attachments.—1, To the bodies of the three or four last dorsal, and to all the lumbar vertebra, by the anterior extremity of its fleshy fibres; 2, To the ilio-pectineal eminence and the lumbo-iliac aponeurosis, by the posterior extremity of its tendon. Relations.—By its inferior face with the pleura, the superior border of the diaphragm, the aorta or posterior vena cava, and the great sympathetic nerve; by its upper face, with the psoas magnus. It is traversed, near its vertebral insertions, by numerous vascular and nervous branches. Actions.—It flexes the pelvis on the spine, when the loins are the fixed point ; but should the pelvis be fixed, it arches or laterally inclines the lumbar region. It is also the tensor muscle of the lumbo-iliac aponeurosis. Fig. 109. 5. Square Muscle of the Loins. (Fig. 109, 1.) Synonyms. — Sacro-costalis — Girard. (Sacro-lumbalis— Pereivall. Quadratus lumborum of Man.) Situation — Form — Structure —Attachments—This muscle is comprised between the trans- verse processes of the lumbar region and the great psoas, and is elongated from before to be- hind, flattened above and below, and divided into several very tendinous fasciculi. The prin- cipal fasciculus, situated out- wardly, takes its origin from the sacro-iliac ligament, near the angle of the sacrum, and ex- tends directly forward to gain the posterior border of the last rib, after being attached by its upper face to the summits of the transverse processes of the lum- DEEP MUSCLES OF THE SUBLUMBAR REGION. Quadratus lumborum; 2, 2, Intertransversales : a 8, Small retractor muscle of the last rib—a de- bar vertebre, The other fasei pendent of the small oblique of the abdomen. culi are: longer as they are an- terior; they leave the internal border of the first, and are directed obliquely forward and inward, to be MUSCLES OF THE TRUNK 215 fixed into the transverse processes of the majority of the lumbar vertebra, and the inner face of the two or three last ribs. Relations.—By its upper face, with the intertransversales, the small retractor of the last rib, and the fibrous fascia which unites that muscle to the small oblique of the abdomen. By its inferior face, to the great psoas. Actions.—It draws the last ribs backwards, and inclines the lumbar spine to one side. 6. Intertransverse Muscles of the Loins. (Fig. 109, 2, 2.) (Synonym—Intertransversales lumborum—Percivall.) These are very small flat muscles which fill the intervals between the transverse processes of the lumbar vertebre. The muscular fibres entering into their composition are mixed with tendinous fibres, and are carried from We anterior border of one transverse process to the posterior border of the other. They respond, by their superior face, to the ilio-spinalis (longissimus dorsi), and by their inferior face to the quadratus, as well as the psoas magnus. They act by inclining the lumbar region to one side. DIFFERENTIAL CHARACTERS OF THE MUSCLES OF THE SUBLUMBAR REGION IN OTHER ‘ THAN SOLIPED ANIMALS. In Ruminants and the Pig, the muscles of this region so closely resemble those of Solipeds, that a special description is unnecessary. In the Dog, the great psoas is little developed, and only commences at the third, or even the fourth lumbar vertebra; the iliac psoas is very slender, particularly in its external portion ; otherwise it is scarcely distinct from the great psoas, with which it may be said to form one muscle; the small psoas is relatively larger than the great; it is not - prolonged into the pectoral cavity, and its anterior extremity is confounded with the quadratus lumborum, which is longer and stronger than in all the other animiuls. COMPARISON OF THE SUBLUMBAR MUSCLES OF MAN WITH THOSE OF ANIMALS. In human anatomy, by the names of psoas and iliacus are described the greut psoas and iiiae psoas of animals. The psoas magnus of May is distinguished from that of £olipeds by its superior insertions, which do not go beyond the last dorsal vertebrae. The small psoas is often absent; when present, it is attached, above, to the bodies of the twelve dorsal vertebrae. below, to the ilio-pectineal crest. The intertransversales have been studied with the muscles of the back. The quadratus of the loins, classed by anthropotomists with the abdominal muscles, is distinctly divided into three series of fasciculi: ¢dio-costul fasciculi, which pass from the upper border of the ilium to the twelfth rib; lwmbo-costal fasiculi, passing from the transverse processes of the three or four last lumbar vertebrae to the twelfth rib, and ilio- lumbar fasciculi, going from the iliac crest to the posterior face of the transverse processes of all the Jumbar vertebra. COCCYGEAL REGION. This region is composed of four pairs of muscles destined for the movements of the tail: three, named the sacro-coccygeal, are disposed longitudinally around the coccygeal vertebrae, which they completely envelop; the fourth is designated the ischio-coccygeus. 1. Sacro-coccygeal Muscles. (Fig. 181, 1, 2, 3.) These three muscles are inclosed, with those of the opposite side, in a common aponeurctic sheath which is continuous with the inferior ilio-sacral and sacro-ischiatic ligaments. They commence on the sacrum, are directed backwards and parallel with the coccyx, gradually diminishing in thickness, and are decomposed into several successive fasciculi terminated by small 216 THE MUSCLES, tendons, which are inserted into each of the coceygeal bones. With regard to their situation, these muscles are distinguished as sacro-coccygeus superior, sacro-coccygeus inferior, and sacro-coccygeus lateralis. a. Sacro-coccygeus Superior. (Synonym.—Erector coceygis— Percivall.) The fasciculi which form this muscle take their fixed insertion either from the summits and sides of the three or four last processes of the super- sacral spine, or from the coccygeal vertebre themselves. ‘The tendons through which they effect their movable insertion into these vertebre are always very short. This muscle, covered by the coccygeal aponeurosis, in turn covers the vertebra it is designed to move. It responds: inwardly, to the analogous muscle of the opposite side ; outwardly, to the lateral sacra-coccygeus, and, near its anterior extremity, to a very strong aponeurotic expansion which separates it from the transverse spinous muscle. It directly elevates the tail, or pulls it to one side, according as it acts in concert with its fellow or singly. b. Sacro-coccygeus Inferior. (Synonym.—Depressor coccygis—Percivall.) This muscle is thicker than the preceding; its constituent fasciculi take their origin from the inferior surface of the sacrum, towards the third vertebra, and from the internal face of the sacro-ischiatic ligament and the coccygeal bones. It readily divides into two parallel portions, which Bourgelat has described as two separate muscles. The fasciculi of the internal portion are inserted, by their posterior extremity, into the inferior face of the first coccygeal vertebra. Those of the external portion are all furnished with strong superficial tendcns, néi.rly all of which are for the bones of the tail. This muscle responds : outwardly, to the ischiatic ligament, the ischio- coccygeus and coccygeal aponeurosis ; inwardly, to the muscle of the opposite side, and to the coccygeal attachment of the rectum; above, to the sacrum, the bones of the tail, and the lateral muscle; below, to the rectum and the coccygeal aponeurosis. It either directly depresses the tail or inclines it to one side. ce. Sacro-coccygeus Lateralis. (Synonym.—COurvator coccygis—Percivall.) This muscle may be considered as the transverse spinous of the coccygeal region; indeed, it is confounded with that muscle of the back and loins by its anterior extremity, and appears to continue it to the inferior extremity of the tail. The fasciculi composing it have their origin from the spinous processes of the last lumbar vertebra, through the medium of the transverse spinous, and from the coceygeal bones. The tendons terminating these fasciculi are deep and not very distinct. It responds; outwardly, at the posterior extremity of the ilio-spinalis, to the inferior ilio-sacral ligament and the coccygeal aponeurosis; inwardly, to the transverse spinous and the coccygeal vertebra ; above, to the superior muscle; below to the inferior muscle, from which it is nevertheless MUSCLES OF THE HEAD, 217 separated by several small independent muscular fasciculi, which are carried from one coccygeal vertebra to another. (Leyh designates these the inter. transversales of the tail.) It inclines the tail to one side. 2. Ischio-coceygeus. (Fig 181, 41.) Synonym.—Compressor coccygis—Percivall.) A small, thin, wide, and triangular muscle, situated against the lateral wall of the pelvis, at the internal face of the sacro-ischiatic ligament. It is attached, by an aponeurosis, to that ligament and to the ischiatic crest; it is then directed upwards to be fixed, by its muscular fibres, to the side of the last sacral vertebra and the first two coccygeal bones. It is related, outwardly, with the sacro-ischiatic ligament, and inwardly to the lateral sacro-coccygeus and the rectum. It depresses the entire caudal appendage. REGION OF THE HEAD. The head comprises a large number of muscles, of which only those covering the bones of the face, and those which move the lower jaw and os hyoides, will be described. The others will be studied with the apparatus to which they belong. A. Facial Region. This region includes those muscles of the head which form a part of the framework of the lips, cheeks, and nostrils: that is, all those which are grouped around the face, properly called. Authors are far from being unanimous with regard to the nomenclature and description of these muscles. Girard recognised eleven, to which he gave the following names: labialis, alveolo-labialis, zygomatico-labialis, lachrymo-labialis, supernaso-labialis, super- mawillo-labialis, supermamill.-nasalis magnus, supermasxillo-nasalis parvus, transversalis nasi, maxillo-labialis, mento-labialis. To these eleven muscles, three of which are single, two others are added; these were described by Bourgelat as the middle (intermediate) anterior and middle (intermediate) pos- terior muscles, which Girard wrongly considered as belonging to the labial. ' 1. Labialis, or Orbicularis of the Tips. (Fig. 110, 27.) (Synonym.—Orbicularis oris—Percivall.) Preparation.—Remove with scissors the skin covering the two portions of this muscle; afterwards the buccal mucous membrane and subjacent glands within the lips, to expose its internal face. The labialis, disposed as a sphincter around the anterior opening of the mouth, is regarded as the intrinsic muscle of the lips, and is composed of two portions or fasciculi, one for the upper, the other for the lower lip. United to each other at the commissures of the mouth, and confounded with the superficial layer of the alveolo-labialis, which they appear to continue, these two muscular portions also receive a large portion of the fibres belonging to the majority of the extrinsic muscles, such as the supermaxillo- nasalis magnus and supernaso-labialis. The orbicularis is not attached to the neighbouring bone ; its component fibres affecting a circular form, have, consequently, neither peginning nor ending, except in being continuous with other fibres. The internal face of the superior fasciculus responds to a layer of salivary 218 THE MUSCLES. glands, which in part separate it from the buccal mucous membrane. The external, covered by the skin, adheres to it in the most intimate manner, and. is found isolated from it only on the median line, at first by the aponeurotic expansion of the supermaxillo-labialis, then by a musculo-fibrous layer analogous to that which forms the mento-labialis. _ By its internal face, the inferior fasciculus likewise responds to the buccal mucous membrane, and to some salivary glands. By its external face, it Fig, 110. SUPERFICIAL MUSCLES OF THE FACE AND HEAD. 1, Temporo-auricularis externus, or attollens maximus; 2, Levator palpebra, or corrugator supercilii; 3, Temporo-auricularis internus, or attollens posterior ; 4, 5, Zygomatico-auricularis, or attollens anterior; 6, Orbicularis palpebrarum; 7, Parotido-auricularis, or deprimens aurem; 8, Parotid gland; 9, Temporal, or subzygomatic vein; 10, Ditto, artery; 11, 12, Superior and inferior maxillary nerves; 13, Fascia of the masseter muscle; 14, Nasal bones; 15, Supernaso- labialis, or levator labii superioris alzeque nasi; 16, Supermaxillo-labialis, or nasalis longus labii superioris; 17, External maxillary or facial artery; 18, Facial vein; 19, Supermaxillo-nasalis magnus, or dilatator naris lateralis; 20, Superior maxillary nerve; 21, Zygomatico-labialis, or zygomaticus; 22, Parotid, or Stenon’s duct; 23, Masseter; 24, Alveolo-labialis, or buccinator ; 25, Super- maxillo-nasalis parvus, or nasalis brevis labii superioris; 27, Labialis, or orbicu- laris oris; 28, Maxillo-labialis, or depressor labii inferioris; 29, Mento-labialis, or levator menti. forms an intimate union with the cutaneous integument, like the superior fasciculus. This muscle plays the part of a constrictor of the anterior opening of the mouth, and has complex functions to perform in suction, the prehension of food, and in mastication. 2. Alveolo-labialis. (Fig. 110, 24.): Synonyms,—Molaris externus et internus—Bourgelut. (Buceinator—Percivall. Leyh divides this muscle into two portions; its superficial plane he designates the buccinator, and the deep plane the molaris.) Preparation.—Proceed to the ablation of the masseter; dissect the external surface of the muscle, taking care of the risorius Santorini and zygomaticus, which are confounded with it. Then divide-it in the middle, as far as the commissure of the lips; turn down each strip on the jaws, and remove the mucous membrane, in order to study the ete face of the muscle and the attachments of the superficial plane to the maxillary ones, MUSCLES OF THE HEAD. 219 Situation—Form.—Situated on the sides of the face, partly concealed by the masseter muscle, and applied to the mucous membrane of the cheeks, the alveolo-labialis is a flat, thin muscle, elongated in the direction of the head and formed of two superposed planes. __Extent—Structure—Attachments.—The deep plane, the longest and least wide, is narrower at its extremities than its middle, and is formed of strongly aponeurotic muscular fasciculi, which are attached, posteriorly: 1, To the alveolar tuberosity ; 2, To the external surface of the superior maxillary bone, above the last three molar teeth; 8, To the anterior border of the inferior maxillary bone, behind the sixth molar, in common with the maxillo- labialis. On reaching the commissure of the lips, this muscular layer appears to be continued by small tendons with the fibres of the orbicularis. The superficial plane only begins about the middle of the deep one, whose anterior half it entirely covers. Its fibres, less tendinous than those of the latter, extend from a median raphé which also divides the deep layer in its length, and are directed, some forwards, some backwards, to terminate in the following manner : the first are inserted into the external face of the super- maxillary bone, above the first molar tooth and the superior interdental space ; the second are attached to the inferior interdental space alone. Relations.—Externally, with the masseter, zygomatico-labialis, cuticularis, great supermaxillo-nasalis, supernaso-labialis, the parotid duct, which crosses it to enter the mouth, and the facial artery and veins; internally, with the buccal mucous membrane. The deep plane is accompanied and covered at its anterior border by the upper molar glands; its posterior border is margined by the inferior molar teeth, which it partially covers. The superficial layer is distinctly separated from the deep one in its anterior part, which is attached to the superior maxillary bone. Behind, these two planes adhere more intimately to one another, though they are found completely isolated by an interstice in which one or two large veins pass. Actions —The function of the alveolo-labialis is particularly related to mastication : this muscle, in fact, pushes between the molar teeth the portions of food which fall outside the alveolar arches ; but it cannot aid in bringing the two jaws together, as M. Lecoq has correctly observed. 3. Zygomatico-labialis. (Fig. 110, 21.) Synonyms.—Portion of the cuticularis of Bourgelat. The zygomatecus major of Man. (Zygomaticus—Percivall.) A very small, pale, and thin ribbon-like muscle, arising from the surface of the masseter, near the maxillary spine, by an aponeurosis which is con- founded with the cuticularis; it terminates on the surface of the alveolo- labialis, at a short distance from the commissure of the lips. Covered by the skin, it covers the alveolo-labialis muscle, and some of the superior molar glands, vessels, and nerves. . This muscle pulls backwards the commissure of the lips when it is in a state of contraction. 7 In Solipeds there is also sometimes found a muscle resembling the zygomaticus minor of Man. It is a very small fasciculus situated under the preceding muscle, near its superior extremity. It appears that this fasciculus is continued, above, by the fibres of the lachrymo-labialis, and is lost, below, on the alveolo-labial surface, a little beneath the carotid canal. 220 THE MUSCLES. 4, Lachrymo-labial, or Lachrymal Muscle. (Synonym.—Not mentioned by Percivall. It is the énferior palpebral muscle of Leyh.) A wide and very thin muscle, situated superficially below the eye: it is continuous, in front, with the supernaso-labialis; behind, with the cu- ticularis; above, with the orbicularis of the eyelids. Its fibres, partly muscular and partly aponeurotic, leave the external surface of the lachrymal and zygomatic bones, are directed downwards, and become lost in a cellular fascia which covers the alveolo-labialis ; some pass beneath the zygomatico- labialis and form the zygomaticus minor, when this is present. This muscle is supposed to corrugaterand twitch the skin below the eye. ; ui 5. Supernaso-labialis. (Fig. 110, 15.) Synonyms.—The maxillaris of Bourgelat. The levator labii superioris aleque nasi of Man. (Levator labii superioris aleque nasi—Percivall. Fronto-labialis—Leyh.) Sitwation— Direction—Form—Structure.—Situated on the side of the face, in an oblique direction downwards and backwards,! the supernaso- labialis is a wide muscle, flattened on both sides, elongated from below to above, aponeurotic at its superior extremity, and divided inferiorly into two unequal branches, between which passes the great supermaxillo-nasalis, Attachments.—It has its origin, by its superior aponeurosis, from the frontal and nasal bones, and unites on the median line with the muscle of the opposite side. Its anterior branch, the widest and thickest, goes to the external ala of the nose and to the upper lip, where its fibres are confounded with those of the orbicularis. The posterior branch terminates at the commissure of the lips. Relations.—Outwards, with the skin; inwards, with the supermaxillo- labialis, the posterior portion of the small supermaxillo-nasalis, and vessels and nerves. Its posterior branch covers the great supermaxillo-nasalis, and the anterior is covered by that muscle. Actions.—It elevates the external ala of the nose, the upper lip, and the commissure of the lips. 6. Supermawillo-labialis. (Fig. 110, 16.) Synonyms.—Levator labii superioris of Bourgelat. The levator labii superioris proprit of Man. (Nasalis longus labii superioris—Percivall.) Sitwation—Direction—Form— Structure.—Lying vertically on the side of the face, below the supernaso-labialis, this muscle is a thick and conical fleshy mass, terminated inferiorly by a tendon. Attachments.—It is attached, by the upper extremity of its fleshy body, to the external surface of the supermaxillary and zygomatic bones—origin. Its terminal tendon passes over the transverse muscle of the nose, to unite with that of the opposite side, and with it to form a single aponeurotic expansion, which dips by small fibres into the subcutaneous musculo-fibrous tissue of the upper lip. Relations.—Covered by the lachrymal and supernaso-labialis muscles, this muscle in turn covers the supermaxillary bone, the bottom of the false nostril, the small supermaxillo-nasalis, and the transversalis nasi. Actions.—It raises the upper lip, either directly or to one side, as it acts singly or in concert with its congener. " It is to be remembered that we suppose the head maintained in a vertical position, f MUSCLES OF THE HEAD. 221 7. Great Supermawillo-nasalis. (Fig. 110, 19.) Synonyms.—The pyramidalis-nasi of Bourgelat, The cuninusof Man. (Dilatator naris lateralis—Percivall.) Situation—Direction—Form—Structure.—This muscle, situated on the side of the face, between the two branches of the supernaso-labialis, in an almost vertical direction, is of a triangular form, and slightly tendinous at its summit. Aitachments.—It has its origin, by the aponeurotic fibres of its summit, from the external face of the supermaxillary bone, below its ridge.—It terminates, by its base, on the skin covering the external wing of the nostril, ie a posterior fibres being confounded with those of the orbicularis of the lips. Relations.—Outwardly, with the skin and the inferior branch of the supernaso-labialis ; inwardly, with the anterior branch of that muscle, and with vessels and nerves. Actions.—It dilates the external orifice of the nasal cavity, by pulling outwards the external wing of the nostril. ‘ { 8. Small Supermawillo-nasalis, (Fig. 110, 25.) Synonyms.—The nasalis brevis, and portion of the subcutaneous muscle of Bourgelat. (Nasalis brevis labit superioris—Percivall.) Girard has described, by the above name, a small, thick, and short muscular fasciculus which covers the external process of the premaxillary bone, and whose fibres, either originating from that, the supermaxillary bone, or the internal face of the supernaso-labialis muscle, terminate in the skin of the false nostril, and the appendix of the inferior turbinated bone. Rigot has attached to this muscle that described by Bourgelat as the short muscle. The latter is composed of short, transverse fibres, applied to the expansion of the cartilaginous septum of the nose which projects laterally beyond the nasal spine. These fibres abut, by their most eccentric extremities, against the skin of the false nostril and the appendix of the superior turbinated bone. In adopting Rigot’s description, it is found that the small supermaxillo- nasalis is composed of two portions, which border the re-entering angle formed by the large process of the premaxillary bone and the nasal spine. These two portions, posterior and anterior, unite at their upper extremities. The first appears to be confounded, below, with the middle anterior (depressor ale nasi), the second is continuous with the transversalis nasi. When they contract, they concur in the dilatation of the false nostril and the proper nasal cavity. JY 9. Transversalis Nasi. Synonym.—{ Dilatator naris anterior—Pereivall.) A single, short, and quadrilateral muscle, flattened before and behind, applied to the widened portion of the nasal cartilages, and composed of transverse fibres proceeding from one cartilage to the other. Covered by the skin and the aponeurotic expansion of the two elevator muscles of the upper lip, the transverse muscle of the nose covers the cartilages to which it is attached, and is confounded below with the orbicularis of the lips. Designed to bring together the internal alee of the nose, this muscle ought to be considered more particularly as the dilator of the nostrils. 222 THE MUSCLES. \ 10. The Middle (Intermediate) Anterior Muscle. Synonyms —Medius anterior—Bourgelat. Myrtiformis of Man. (Depressor labii supertori—Percivall. Incisive muscle of the upper lip—Leyh. A portion of the ..« orbicularis, according to Rigot.) Bourgelat thus names a deeply-situated muscle which is fixed to the inner face of the premaxillary bone, above the incisor teeth, and whose fibres ascend to meet those of the posterior portion of the small super- maxillo-nasalis muscle, to terminate with them on the anterior appendix of the inferior turbinated bone; some fibres become lost in the lip. Itis regarded as a dilator of the entrance to the nasal fossa. To study this muscle, it is necessary to raise the upper lip and remove the mucous membrane covering it. It may be dissected at the same time as the bony attachments of the superficial plane of the alveolo-labialis muscle. 11. Mazillo-labialis. (Fig. 110, 28.) Synonyms.—Depressor labii inferioris—Rigot. A dependency of the buccinator of Man. (Depressor labii inferioris—Percivall. Inferior maxillo-labtalis—Leyh. Depressor angult oris of Man.) Situation—Direction—Form—Structure.—Situated along the inferior border of the alveolo-labialis, whose direction it follows, this muscle forms a long narrow fasciculus, terminating inferiorly by an expanded tendon. ‘Attachments —1, By its superior extremity, to the anterior border of the lower jaw, in common with the deep plane of the alveolo.labialis—fixed origin ; 2, By its terminal tendon, to the skin of the lower lip—movable insertion. Relations.—Outwardly, with the masseter and the facial portion of cuticularis of the neck; inwardly, with the maxillary bone; in front, with the alveolo-labialis muscle, with which it is directly united in its upper two- thirds. Actions.—It separates the lower from the upper lip, and pulls it to the side if one alone acts. in 12. Mento-labialis or Muscle of the Chin. (Fig. 110, 29.) (Synonyms.—Percivall appears to describe this and the next muscle as one. It is the quadratus menti of Man.) This name is given to a musculo-fibrous nucleus, forming the base of the rounded protuberance beneath the lower lip in front of the beard. This single nucleus is confounded, in front, with the orbicularis of the lips, and receives into its upper face the insertion of the two posterior middle muscles (levatores menti). 13. Middle (Intermediate) Posterior Muscle. Synonyms.~- Medius posterior—Bourgelat. (Levator menti—Percivall. Incisive muscle of the lower lip—Leyh.) Bourgelat describes, by this name, a small muscular fasciculus, analogous in every respect to the medius anterior. This little muscle takes its origin from the external surface of the body of the lower jaw, beneath the inter- mediate and corner incisors; from thence it descends into the texture of the lip, to unite with that of the opposite side on the upper face of the,amento- labialis. Several authors have described it as a dependent of the last miigcle. MUSCLES OF THE HEAD. 223 It is an energetic elevator of the lower lip. To dissect this muscle, the directions given for the preparation of the anterior medius will suffice. B. Masseteric or Temporo-maxillary Region. _ ‘This pair region comprises five muscles for the movement of the lower. Jaw. These are: the masseter, temporal, internal pterygoid, external pterygoid, and digastricus. Preparation.—1. First study the digastricus and its stylo maxillary portion, with the internal pterygoid, in preparing the hyoid muscles as they are represented in fig. 111. 2, Expose the pterygoideus externus, by removing in this preparation the hyoid bone and its dependencies, as well as the two preceding muscles. 3. To dissect the temporalis, excise the external pterygoideus from its inferior border, an operation which exposes the orbital fasciculus of the temporalis; then turn over the piece, saw off the orbital process at each end, and remove the eye and auricular muscles. 4. Dissect the masseter in clearing away from its external surface the cuticularis and the vessels and nerves which cover it. 1. Masseter, (Fig. 110, 23.) Synonyms.—Zygomatico-maxillaris—Girard, (The zygomatico mazillaris of Leyh.) Situation—Form —Structure.— Applied against the external face of the lower jaw, the masseter is a short, wide, and very thick muscle, flattened on both sides, irregularly quadrilateral, and formed of several superposed planes, two of which are perfectly distinct towards the temporo-maxillary articula- tion, by the somewhat different direction of their fibres. These are divided by a considerable number of intersections, and are covered by a strong aponeurotic layer, which becomes gradually thinner backwards and down- wards. Attachments.—The fasciculi of the masseter have their fixed insertion on the zygomatic crest.—Their movable insertion is on the imprints which cover the upper half of the inferior maxillary branch. Relations—It responds, by its superficial face, to the facial portion of cuticularis colli, to the nerves of the zygomatic plexus, and several venous and arterial vessels; by its deep face, to the inferior maxillary bone, the alveolo-labialis and maxillo-labialis muscles, the superior molar glands, and two large venous branches; by its inferior border, with the parotid canal, and the glosso-facial artery and vein; by its superior and posterior border, to the parotid gland. Its deep plane responds, anteriorly, with the temporo- maxillary articulation, and is so intimately confounded with the temporalis, that it is impossible to define the respective limits of the two muscies. Action.—This muscle, the special elevator of the lower jaw, plays an important part in mastication. It always acts as a lever of the third class, the middle line, which represents the resultant of all its constituent fibres, passing behind the last molar. 2. Temporal or Crotaphitic Muscle. Synonyms.—Temporo-maxillaris—Girard. (The temporo-maxillaris of Leyh.) Situation— Form— Structure—Situated in the temporal fossa, to which it is moulded, and which it fills, this muscle is flattened from above to below, divided by strong tendinous intersections, and covered by a nacrous aponeygotic layer. Give takes its origin: 1, In the temporal fossa and on the 224 THE MUSCLES. bony crests which margin it; 2, By a wide fasciculus, paler than the other portion of the muscle, but not unconnected with it, from the imprints situated behind the crest surmounting the orbital hiatus. It terminates on the coronoid process and the anterior border of the branch of the lower anv. : Relations.—This muscle covers the temporal fossa, and is covered by the temporo-auricularis muscles, scutiform cartilage, internal scuto-auricularis, the fatty cushion at the base of the ear, and by another adipose mass which separates it from the ocular sheath. Its deep fasciculus responds, by its internal face, to the two pterygoid muscles. Action.—It brings the lower jaw in contact with the upper, by acting as a lever of the first kind; but the orbital portion of the muscle elevates tho inferior maxilla and moves it laterally by a lever of the third class. 3. Internal Pterygoid. Synonyms.—Portion of the spheno-maxillaris of Bourgelat. (The pterygoideus internus of Percival]. Leyh designates the pterygoideus internus and externus as one muscle, tha spheno-maxillaris or internal masseter.) Situation—Form—Structure—Situated in the intermaxillary space, opposite the masseter, the pterygoideus internus, although not so strong as that muscle, yet so closely resembles it in form and structure as to be named by Winslow the internal masseter. Attachments—1. To the palatine crest and subsphenoidal process—fixed insertion: 2. In the hollow excavated on the inner face of the branch of the lower jaw—movable insertion. Relations—Outwardly, with the pterygoideus-externus, the orbital fasciculus of the temporal, the maxillo-dental nerves, mylo-hyoideal, and lingual muscles, arteries and veins, and the inner surface of the bone which receives its movable insertion. Inwardly, with the tensors palati—external and internal, the guttural pouch, the hyoideus magnus, hyoid bone, digastricus, the hypoglossal and glosso-pharyngeal nerves, glosso-facial artery and vein, the hyoglossus longus and brevis muscles, the laryngo-pharyngeal apparatus, the Stenonian duct, and the submaxillary glands. Action.—It is an elevator of the lower jaw, and also gives it a very marked lateral or deductive motion. If the left muscle acts, this movement carries the inferior extremity of the lower jaw to the right; and if it be the right muscle, then in the contrary direction. 4, Haternal Pterygoid. Synonym.—Portion of the spheno-maxillaris of Bourgelat. Form—Situation—Structure—Attachments—A small, short, and very thick muscle, situated within and in front of the temporo-maxillary articulation, formed of slightly tendinous fasciculi which leave the inferior face of the sphenoid bone and the subsphenoidal process, and are directed backwards and upwards to be fixed to the neck of the inferior maxilliry condyle. Relations.—Outwardly, with the orbital fasciculus of the temporal muscle, and the temporo-maxillary articulation. Inwardly, with the numerous nerves emanating from the inferior maxillary branch, and with the internal pterygoid and tensors palati. Action.—When the two external pterygoids act in concert, oo maxilla is pulled forward; but if only one contract, the propu is MUSCLES OF THE HEAD. 225 accompanied by a lateral movement, during which the extremity of the jaw is carried to the opposite side. 5. Digastricus. Synonyms.—Bourgelat has made two disti is— i i etylomasilass, gee ee described AE igre Ba ig et tne ev. ollowe: ourgelat's ex ivi i igastré to paler, Leyh ae sak tien ne the muscle into digastricus and Form—Structure—Situation—Direction—Composed of two fleshy bodies more or less divided by intersections, and united at their extremities by a median tendon, this muscle is situated in the intermaxillary space, and extends from the occiput to near the symphysis of the chin, describing a curve upwards. Aittachments.—It takes its origin from the styloid process of the occipital bone, by its superior fleshy body. It terminates: 1, On the curved portion of the posterior border of the lower jaw by a considerable fasciculus, which is detached from the superior fleshy body ;! 2, On the internal face of the same bone and the straight portion of its posterior border, by aponeurotic digitations which succeed the muscular fibres of the inferior fleshy body. Relations.—The superior belly of the muscle responds, superficially, to the parotid gland and the tendon of insertion of the sterno-maxillaris; deeply, to the guttural pouch, the submaxillary gland, and the larynx and pharynx. The median tendon passes through the ring of the hyoideus magnus. The lower belly is in contact, outwards, with the ramus of the inferior maxilla; inwards, with the mylo-hyoideus muscle. Action.—When this muscle contracts, it acts at the same time on the hyoid bone, which it raises in becoming straight, and on the lower jaw, which it pulls backwards and depresses at the same time. C. Hyoideal Region. This region includes six muscles grouped around the os hyoides, which they move. Five of these are pairs: the mylo-hyoideus, genio-hyoideus, stylo- hyoideus, kerato-hyoideus, and the occipito-styloideus. ‘The single one is the transversalis hyoidei. Preparation.—Separate ‘the head from the trunk, and remove the muscles of the cheeks on one side, with the parotid gland. 2. The branch of the inferior maxilla being thus exposed, it is sawn through in two places; at first behind the last molar, then in front of the first. 3. After having separated the pterygoids and the stylo-maxillaris from the upper fragment or condyle, and the coronoid process, it is torn off by pulling it backwards ; then the pterygoids and the digastricus are excised. 4. The inferior fragment of the jaw bearing the molar teeth is turned down by isolating the mylo-hyoideus from the mucous membrane. 5. Carefully remove the tongue by separating its extrinsic muscles from the genio-hyoideus, the anterior appendix of the hyoid bone, the transverse muscle, and the small hyoideus, ‘ The dissection having been performed in this manner, the large hyoideal branch may be separated from the small, by sawing through the head longitudinally, leaving the symphysis menti intact, and turning down the corresponding half to the side already dissected, as well as the great hyoid branch, the pharynx, larynx, and soft palate. 1. Mylo-hyoideus. Form—Situation—Structure—A membranous muscle situated in the intermaxillary space, flattened from side to side, elongated in the direction Lgmis is the fasciculus which Bourgelat has described as a distinct muscle, and na the stylo-maxillaris. 226 THE MUSCLES. of the head, thinner and narrower below than above, and formed entirely of fleshy fibres which extend transversely from its anterior to its posterior border, Inferiorly, it is composed of a small fasciculus, which is distinguished from the principal portion by the slightly. different direction of its fibres, and which covers in part the external surface of the muscle, Fig. 11 HYOIDEAL AND PHARYNGEAL REGIONS. 1, Neck of inferior maxilla; 2, Hard palate; 3, Molar teeth ; 4, Buccal membrane; 5, Submaxillary glands; 6, Soft palate; 7, Tendon of hyoideus magnus through which the tendon, 8, of she digastricus passes; 9, Lower portion of digastricus; 10, Stylo-hyoideus; 11, Buccal nerve; 12, Zygomatic arch, 13, Orbital branch of fifth pair of nerves; 14, Articular process of temporal bone; 15, Right cornu of hyoid bone; 16, Hyo-glossus longus, or Kerato-glossus; 17, Lingual nerve; 18, 18, Tongue; 19, Angle of left branch of inferior maxilla; 20, Submaxillary gland, left side; 21, Subscapulo-hyoideus; 22, Great hypoglossal nerve; 23, Hyo- thyroideus; 24, Sterno-hyoideus; 25, Sterno-thyroideus; 26, Subscapulo hyoi- deus; 27, Thyroid gland; 28, External carotid artery ; 29, Pneumogastiic nerve; 30, Stylo-hyoideus ; 31, Genio-hyoideus, Attachments.—It originates from the mylo-hyoid line by the anterior extremities of its fibres. Its movable insertion takes place on the inferior face of the hyoid body, on its anterior appendix, and on a fibrous raphé which extends from the free extremity of this appendix to near the genial surface, and which unites, on the median line, the two mylo-hyoidean muscles. Relations.—By its external face, with the inferior maxilla, the digastric muscle, and the submaxillary lymphatic glands. By its internal face, with the sublingual gland, the Whartonian duct, the hypoglossal and lingual nerves, the genio-glossus, hyo-tlossus longus and brevis, and genio-hyoideus. Its superior border responds to the internal pterygoid. Action.—In uniting on the median line with that of the opposite side, this muscle forms a kind of wide band or brace on which the tongue rests. When it contracts, it elevates this organ, or rather applies it against the palate. 2. Genio-hyoideus. Form—Structure—Situation.—A. fleshy, elongated, and a i. tendinous at its extremities, but especially at the inferior one, and ap , with its fellow of the opposite side, to the mylo-hyoidean brace. MUSCLES OF THE HEAD, 227 : Attachments— By its inferior extremity it is fixed to the genial surface— origin ; by its superior, it reaches the free extremity of the anterior appendix of the hyoid body—-termination. Relations.—Outwards und downwards, with the mylo-hyoideus ; inwards, with its fellow, which is parallel to it; above, with the genio-glossus. Action.—It draws the hyoid bone towards the anterior and inferior part of the intermaxillary space. 8. Stylo-hyoideus. (Synonyms.—The hyoideus magnus of Percivall. The kerato-hyoideus magnus of Leyh.) Form — Structure — Situation — Direction —Thin and fusiform, this muscle, smaller than the preceding, and, like it, tendinous at both its extremities, is situated on the side of the laryngo-pharyngeal apparatus and the guttural pouch, behind the large branch of the hyoid bone, whose direction it follows. Attachments.—Above, to the superior and posterior angle of the styloid bone—fiwed insertion; below, to the base of the cornu of the os hyoides —movable insertion. Relations—Outwards, with the pterygoideus internus; inwards, with the guttural pouch, the pharynx, and hypoglossal nerve. Its anterior border is separated from the posterior border of the styloid bone by the glosso-facial artery and glosso-pharyngeal nerve; along the posterior border lies the upper belly of the digastricus, Its inferior tendon is perforated by a ring for the passage of the cord intermediate to the two portions of the latter muscle. Action.—It is antagonistic to the preceding muscle, drawing the body of the hyoid bone backwards and upwards. 4. Kerato-hyotdeus. ‘; ae is the hyoideus parvus of Percivall, and the small kerato-hyoideus of eyh ) A very small fasciculus, triangular in shape, and flattened on both sides. Inserted, on one side, into the posterior border of the styloid cornu and the inferior extremity of the styloid bone; and on the other, to the superior border of the thyroid cornu. It responds, outwardly, to the basio-glossus and the lingual artery; inwardly, to the buccal mucous membrane. It approximates the cornua of the os hyoides to each other. 5. Occipito-styloideus. Synonyms.—This is the muscle which, up to the present time, has been described by veterinary anatomists as the stylo-hyoideus. This name has been given to the muscle named by Girard the kerato-hyoideus magnus. A small, flat, and triangular muscle like the preceding, yet thicker and more spread, filling the space comprised between the styloid process of the occipital and the horizontal portion of the posterior border of the styloid bone. Its fasciculi become longer as they are situated posteriorly, are rather tendinous, and are carried from one of these bones to the other. Outwardly, it responds to the parotid gland; inwardly, to the guttural pouch, which it covers for its whole extent; its posterior border is largely confounded with the superior insertion of the digastricus. When this muscle*acts, it causes the os hyoides to swing, carrying its inferior extremity backwards and downwards. 228 THE MUSCLE 6. Transversalis Hyoidet. By this name Bourgelat has described a short riband of parallel muscular fibres, which unites the superior extremities of the styloid cornua, and approximates them to each other. : DIFFERENTIAL CHARACTERS OF THE MUSCLES OF THE HEAD IN OTHER THAN SOLIPED ANIMALS. : A. Facial Region. Rominants.—There are found in the Oz. 1. An orbicular muscle of the lips, analogous to that in the Horse. 2. An alveolo-labialis of the same kind (fig. 112, 5). 3. A zyqomaticus or zygomatico-labialis, stronger and redder than in Solipeds. Its aponeurosis of origin, covered by the cuticularis muscle of the face, extends upon. the surface of the masseter muscle as far back as the zygomatic arch, to which it ig attached (fig. 112, 7). Fig. 112. SUPERFICIAL MUSCLES OF THE OX’S HEAD. 1, Supermazillo-labialis; 1, 1’, Accessory fasciculi of the supermaxillo-labialis ; 2, Supermaxillo-nasalis magnus; 3, Supernaso-labialis; 4 Lachrymalis; 5, Alveolo-labialis; 6, Maxillo-labialis confounded with the preceding; 7, Zygo- matico-labialis; 8, Frontal, or cuticularis muscle of the forehead; 9, Orbicular muscle of the eyelids; 10, Zygomatico-auricularis; 11, External temporo-auricu- laris; 12, Scutiform cartilage; 13, External scuto-auricularis; 14, Mastoid process; 15, Masseter; 16, Stylo-hyoideus; 17, Digastricus; 18, Sterno-maxil- lary fasciculus belonging to the cuticularis muscle of the neck; 19, Trachelo- hyoideus (subscapulo-hyoideus); 20, Sterno-suboccipitalis (sterno-maxillaris, or mastoideus); 21, Anterior branch of the superficial portion of the mastoido- humeralis (levator humeri); 22, Superior branch of ditto; 23, Deep portion of same muscle; 24, Trachelo-atloideus, peculiar to Ruminants and Pachyderms ; 25, Great anterior straight muscle of the head, MUSCLES OF THE HEAD. 229 4. A lachrymalis, thicker and more developed than in the Horse. Its most anterior fibres glide beneath the zygomaticus, and are lost on the alveolo-labialis surface: the most posterior pass over the aponeurotic tendon of the zygomatico-labialis, and are confounded witb those of the cuticularis. Above, it joins the orbicularis of the eyelids in a still more intimate manner than in the Horse; go that it is almost impossible to distinguish the limits of the two muscles (fig. 112, 4). 5. A supernaso-labialis continued, above, with the inferior border of the frontal or fronto-cuticularis muscle; and divided, inferiorly, into two branches, which comprise between them the supermaxillo-labialis and the pyramidalis-nasalis. These two branches, however, are not disposed as in Solipeds, the anterior covering the preceding muscles, and the posterior, of but little importance, passing beneath them to lose itself in the substance of the upper lip (fig. 112, 3). 6. A supermaxillo-labialis, which gains the middle of the muzzle by passing along the inner side of the nostrils (fig. 112, 1). 7. Two additional supermazillo-labialis muscles, considered as accessories to the first, and which originate with it. Each terminates by a ramifying tendon that passes under the nostril to mix in the tissue of the upper lip (fig. 112, 1’,1'). 8. A pyramidalis or great supermasxillo-nasulis, situated between the supermaxillo- labialis and its two accessory muscles, and deriving its origin, in common with these three muscles, in front of the maxillary spine (fig. 112, 2). , 9. A mazillo-labialis, confounded with the alveolo-labialis, and having no terminal endon. 10. A mento-labialis, attached to the body of the inferior maxillary bone, as in the Horse, by two middle posterior muscles. No anterior middle muscle has been found by us; and it is certain that there is no naso-transversalis or small supermazillo-nasalis present. In the Sheep, the supernaso-labialis does not exist; apart from this peculiarity, there is no difference between the facial muscles of this animal and the Ox. Pic.—This animal has neither the lachrymalis, supernaso-labialis, or naso-transver- salis muscles. The small supermaxillo-nasalis is present ; it is short, very thick, and situated near the margin of the nostrils. The supermazillo-labialis and the great supermaxillo-nasalis are replaced by three fleshy bodies, nearly parallel, lying on the side of the face. The superior originates in the lachrymal fossa, and terminates by a tendon in the middle of the snout. The inferior, with the middle, leaves the imprints in front of the zygomatic ridge, and is continued at its inferior extremity by a tendon divided into several fibrille, which pass below the nostril to be united to the tendon of the superior portion : this is done in such a manner that the external opening of the nose is encircled on the inner side by a kind of fibrous cravat which, when these two muscles contract, carries this opening outwards, It will also be understood that the superior fleshy body, acting alone, ought to elevate the snout, while the inferior depresses it in drawing it to one side. With regard to the intermediate fleshy mass, it is the representative of the pyramidalis of the Ox, and terminates in a great quantity of tendinous fibrillz at the internal ala of the nose. Caryivora.—In the Dog and Cat the following peculiarities are found :— The labialis (or orbicularis) is quite rudimentary. The buccinator is very thin and formed of only one muscular plane. The zygomatico-labialis is continued, superiorly, with the zygomato-auricuralis. The supernaso-labialis represents a wide, undivided, muscular expansion, united superiorly to the cuticularis of the forehead, and terminating inferiorly on the upper lip. The supermazillo-labialis and the supermazillo-nasalis magnus constitute a single fleshy body formed of several parallel fasciculi, which take their origin above the supra- orbital foramen, and terminate together at the external wing of the nose and in the upper lip. There is no supermaxillo-nasalis parvus, or naso-transversalis. The middle anterior (depressor alz nasi) is perfectly developed. The mento-labialis and its suspensory muscle. the middle posterior, are scarcely apparent. B. Masseteric or Temporo-mazillary Region. In Ruminants, the masseler and temporal are not so large as in Solipeds. In the Carnivora, however, they offer a remarkable development. The origin of the ptery- goideus internus in Ruminants is nearer the middle line than in the Horse. Its obliquity si also greater, and the movements of diduction it gives the lower jaw are more 18 230 THE MUSCLES. extensive. In all the animals, the stylo-masillaris fasciculus of the digastricus is entirely absent, and the muscle has only a single belly extending directly from the occipital to the maxillary bone. In the Ox is found a small square muscle, formed of transverse fibres, which unites the two digastric muscles by passing beneath the base of the tongue. This muscle, in contracting, may raise the hyoideal apparatus, and in this way supplements the tendon of the digastricus and the inferior ring of the stylo- hyoideus. C. Hyoid Region. The two fleshy planes composing the mylo-hyoideus are more distinct in Ruminants than in the Horse. The stylo-hyoideus of these animals commences by « long thin tendon. The muscle has no ring for the passage of the digastricus, a feature observed in all the domesticated animals except Solipeds. In the Carnivora, the stylo-hyoideus, formed by a narrow, very thin, and pale fleshy band, commences on the mastoid portion of the temporal bone by a small tendon; the kerato-hyoideus is remarkable for its relatively considerable volume ; the oceipito- styloideus and the transversalis hyoideus are absent. COMPARISON OF THE MUSCLES OF THE HUMAN HEAD WITH THOSE OF THE DOMESTICATED ANIMALS, In Man, there are described as muscles of the head, the epicranial muscles, muscles of the face, and those of the lower jaw, The hyoid and digastric muscles are reckoned in the region of the neck. Here they will be placed in the region of the head. A. Epicranial Muscles. The middle portion of the human cranium is covered by an aponeurosis that adheres closely to the hairy scalp, but glides easily on the surface of the bones. To the circum- ference of this epicranial aponeurosis are attached four muscles which move it. One of them, attached behind to the superior occipital curved line, is named the occipital muscle ; another, fixed in front of the forehead, is called the frontal muscle ; the other two, double and lateral, are inserted on the face of the temporal bone or the external ear, and are designated auricular muscles. These epicranial muscles move the scalp for- wards, backwards, and sideways. B. Museles of the Face. These are fourteen in number, ten of which are found in the domesticated animals, We commence by describing these common muscles (fig. 113). 1. The orbicularis of the lips, which has a fasciculus that passes to the skin from the columna of the nose; this fasciculus is termed the depressor of the columna, or moustache muscle (naso labialis). 2. The buccinator, corresponding to the alveolo-labialis of animals. Besides its office in mastication, it takes an important part in the blowing of wind instruments. 3. The superficial elevator of the wing of the nose and the upper lip. It resembles the supernaso-labialis, descends from the orbital margin of the supermaxilla, passes along the wing of the nose, and is lost in the upper lip. 4. The deep elevator of the wing of the nose and the upper lip, whose analogue is found in the supermaxillo-labialis of animals. 5. The great zygomaticus, whose presence is constant in all species. 6. The small zygomaticus. represented in the Horse by only the small oblique fasciculus sometimes found beneath the great zygomaticus. The small zygomaticus and the two elevators of the lips are lachrymal muscles; by their simultaneous contraction they express discontent and melancholy. The great zygomaticus, on the coutrary, is the muscle of laughter; it draws the commissures of the lips outwards. 7. The canine, or great supermaxillo-nasal of animals, is attached beneath the infra- orbital foramen, and terminates in the skin of the upper lip. 8. The risorius of Santorini. 9. The muscle of the chin (mento-lalialis). 10. ‘The myrtiformis, or middle anterior of Bourgelat. The other facial muscles of Man, whose analogues it is difficult or impossible to find in animals, are :— MUSCLES OF THE TRUNK. 231 11. The triangularis of the lips, which is inserted into the anterior face of the inferior maxilla, and is carried upwards to the commissure of the lips. By its contraction it gives the face an expression of melancholy or contempt. 12. The quadratus menti, which, after being attached to the maxilla within the mental fora. men, passes upwards on the skin of the lower lip, which it depresses, and thus contributes to the expression of fear or dismay. 13. The transversalis nasi (compressor nas’), a muscle which is fixed into the supermaxilla and on the bridge of the nose, where it is con- founded with the opposite muscle. 14. The dilator of the ala of the nostril, a very small triangular fasciculus applied to the external part of the nostril, which, by contract- ing, it elevates. C. Muscles of the Lower Jaw. There is nothing remarkable to be noted in the masseter, temporal, or pterygoid muscles, The upper belly of the digastricus is not at- tached directly to the inferior maxilla. D. Hyoid Muscles. These are only three in number :— 1. The mylo-hyoideus. 2. The stylo-hyoideus, which commences at the styloid process of the temporal bone, and shows a ring for the tendon of the digastricus, 3. The genio-hyoideus. We do not find in Man the occipito-styloideus, kerato-hyoideus, or the transversalis-byoideus. Axillary Region. This comprises two muscles, pairs, placed beneath the sternum, in the arm- pit, which terminate on the anterior limb. These are the superficial and deep pec- torals.+ Preparation—i. Place the animal in the first position. 2. Unfasten one of the fore-limbs, and allow it to hang, so as to separate it from the opposite one. 3. Remove the skin with care, and dissect, on the side corresponding to the detached limb, the two muscles which form the superficial pectoral, 4, Prepare the deep pectoral on the opposite side. To do this, Fig. 113. MUSCLES OF THE HUMAN HEAD, SUPERFICIAL LAYER, 1, Frontal portion of the occipito-fronta- lis; 2, Its occipital portion; 3, Its aponeurosis; 4, Orbicularis palpebra- rum; 5, Pyramidalis nasi; 6, Com- pressor nasi; 7, Orbicularis oris; 8, Levator labii superioris aleque nasi; 9, Levator labii superioris proprius ; 10, Zygomaticus minor; 11, Zygo- maticus major; 12, Depressor labii inferioris; 13, Depressor anguli oris; 14, Levator labii inferioris; 15, Super- ficial portion of masseter; 16, Its deep portion; 17, Attrahens aurem; 18, Buccinator; 19, Attollens aurem; 20, Temporal fascia covering temporal muscle; 21, Retrahens aurem; 22, Anterior belly of the digastricus, with tendon passing through pulley; 23, Stylo-hyoid muscle; 24, Mylo-hyoi- deus; 25, Upper part of sterno-mas- toid; 26, Upper part of trapezius— the muscle between 25 and 26 is the splenius. remove the panniculus cautiously, so as not to injure the muscle about to be examined ; divide the superficial pectoral transversely, and turn back the ent portions to the right and left: divide also the mastoido-humeralis (levator humeri) and cervical trapezius near their insertion into the limb, and reflect them upon the neck. 1. Superficial Pectoral. (Fig. 114, 9, 10.) Symonyms.~-Muscle common to the arm and fore-arm—Bourgelat. Pectoralis magnus of Men. t pestoralis transversus—Percivall. Leyh divides this muscle into two portions, which he designates the sterno-radialis and small sterno-humeralis). F.r a justification of the employment of these uew denominations, see the note at p. 177. 232 — \ ( Mi) Wl MUSCLES OF THE AXILLARY AND CERVICAL REGIONS. Portion of the cuticularis colli; 2, An- terior portion of the mastoido-hume- ralis; 3, Posterior portion of ditto; 4, Sterno-maxillaris ; 5, Subscapulo-hyoi- deus; 6, Sterno-hyoideus; 7, Sterno- thyroideus; 8, Scalenus; 9, Sterno- humeralis; 10, Sterno-aponeuroticus ; 11, Sterno-trochineus (pectoralis mag- nus); 12, Portion of the fascia en- veloping the coraco-radialis, receiving part of the fibres of the sterno-trochi- neus; 13, Sterno-prescapularis; 14, {ts terminal aponeurosis, THE MUSCLES. Situation—Composition.—This muscle is situated between the two anterior limbs, occupies the inferior surface of the chest, and is formed by two por- tions which adhere closely to each other, but are yet perfectly distinct. Following the example of Girard, we will describe these as two particular muscles by the names of sterno-humeralis, and sterno- aponeuroticus. A. Srervo-HumeRatis. — Form — Structure.— This is a short, bulky muscle, flattened above and below, contracted at its termination, and composed almost entirely of thick parallel fibres. Direction and Attachments.—It com- mences on the anterior appendage and the inferior border of the sternum, and is directed obliquely backwards, downwards, and inwards, to reach the anterior ridge of the humerus, where it terminates by an aponeurosis common to it, the mas- toido humeralis, and the sterno-aponeuro- ticus. Relations—It responds, by its ex- ternal face, to the skin, from which it is separated by a cellular layer, and to the inferior extremity of the cuticularis colli; by its internal face, to the sterno- aponeuroticus and sterno-prescapularis. Its anterior border forms, with the mas- toido-humeralis, a triangular space occn- pied by the subcutaneous, or “ plate,” vein of the arm. Action—It acts principally as an adductor of the anterior limb. B. Srervo-aponevrotricus.—Form— Structure — Direction — Attachments. —A very wide, thin, and pale quadrilateral muscle formed of parallel fleshy fibres, which arise from the entire inferior border of the sternum, to pass at first outwards, then downwards, and terminate in the following manner: the anterior fibres go to the aponeurosis which attaches the mastoido-humeralis and sterno-hu- meralis to the anterior ridge of the humerus; the posterior fibres are also continued by a very thin fascia, which is spread inside the limb to the external face of the antibrachial aponeurosis. Relations—By its superficial face, MUSCLES OF THE TRUNK. 233 with the skin, which adheres intimately to it by means of a dense cellular tissue, and with the sterno-humeralis, which covers its anterior border. By its deep face, with the two portions of the deep pectoral, the coraco- radialis (flexor brachii), and the long extensor of the fore-arm; it also responds, by this face, to the antibrachial aponeurosis and the sub- cutaneous vein of the fore-arm, which it maintains applied against that aponeurosis, Action—It is an adductor of the anterior limb, and a tensor of the antibrachial aponeurosis. 2. Deep Pectoral. (Figs. 114, 11, 18; 115, 1.) Synonym.—The pectoralis parvus of Man. Volume—Situation—Composition—An enormous muscle, situated be- neath the thorax, and composed, like the preceding, of two perfectly distinct portions, described by Girard as two muscles, and designated by him as the sterno-trochineus and sterno-prescapularis. A. Srerno-rrocuineus.—Pectoralis magnus of (Percivall, Rigot, and) Bourgelat. (The great sterno-humeralis of Leyh.) Volume—Extent.—This muscle, the largest of the two, offers a con- siderable volume. Extending from the ninth or tenth rib to the upper extremity of the arm, it at first lies beneath and against the abdomen, then beneath the chest, and at last is comprised between the walls of the latter cavity, and the internal face of the anterior limb. Form.—It is thin and flat above and below in its posterior third, thicker and depressed from side to side in its middle third, and narrow and pris- matic in its anterior third. Its general form may be compared to that of a somewhat irregular triangle, elongated from before to behind, which would have a very short posterior border, a longer internal or infcrior border, and an external or superior still more extensive. Structure.—It is entirely composed of thick, parallel, fleshy fasciculi, all of which leave the posterior or internal border of the muscle to gain its narrow or anterior extremity. These fasciculi, as they approach the superior border, become longer, and those which proceed from the posterior border com- mence by aponeurotic fibres. Unfrequent intersections of fibrous tissue exist towards the anterior extremity of the muscle. Attachments.—It originates: 1, From the tunica abdominalis by the apo- neurotic fasciculi of its posterior border; 2, By its internal border, from the posterior two-thirds of the inferior border of the sternum. It terminates, by its anterior extremity, on the internal tubercle at the head of the humerus, the tendon of origin of the coraco-humeralis, and the fascia enveloping the coraco-radialis. Through the medium of this fascia, it is inserted into the external lip of the bicipital groove formed by the great trochanter, and is united to the two terminal branches of the supraspinatus muscles. (See Fig. 114, 12.) oes . ; Relations.—Its deep face, which is successively superior and internal, covers the external oblique and the straight muscle of the abdomen, the serratus magnus, costo-sternalis, and sterno-prescapularis, as well as some thoraco-muscular nerves; all these relations are maintained by means of a loose and abundant cellular tissue. Its superior face, which alternately looks downwards and outwards, responds: to the skin, from which it is separated by a slight cellulo-fibrous fascia; to the sterno-aponeuroticus ; and to the muscles, vessels, and nerves of the inner aspect of the arm, through. 234 THE MUSCLES. the medium of the subbrachial aponeurosis of the panniculus and a con- siderable quantity of cellular tissue. Its upper border adheres in an intimate manner to the last-named muscle, and is bordered by the spur (external thoracic) vein. The large vascular trunks which leave the chest to reach Their attachment to the sternum; 5, 16, Panniculus; 8, 19, Levator humeri, ctoral muscle; 11, Sterno-thyroideus; 12, 15, Rhomboideus; 17, Point of sternum ; alis parvus; 3, Superficial pectoral, or pectoralis trans- g aast eye Be ; Bye ak. a a sb ae SaacsD 2esa92 > 8 eeaseq < 5a.8% Bue eva: fe} vom a a Bip govn's H6Enew og eVvgous BP QaZ oO 2AAnOe