Part 1

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Transcriber’s Notes

Text printed in italics in the source document has been transcribed _between underscores_, text printed in bold face =between equal signs=. Small capitals have been transcribed as ALL CAPITALS.

More Transcriber’s Notes may be found at the end of this text.

ANATOMY OF THE CAT

BY

JACOB REIGHARD _Professor of Zoology in the University of Michigan_

AND

H. S. JENNINGS _Instructor in Zoology in the University of Michigan_

WITH _ONE HUNDRED AND SEVENTY-THREE ORIGINAL FIGURES_ DRAWN BY LOUISE BURRIDGE JENNINGS

NEW YORK HENRY HOLT AND COMPANY 1901

ROBERT DRUMMOND, PRINTER, NEW YORK.

PREFACE.

Although the cat has long been in common use for the practical study of mammalian anatomy, a clear, correct, not too voluminous account of its structure, such as should be in the hands of students in the laboratory, has remained a desideratum. A number of works have been published on the cat, some of them of much value, yet there is none which fulfils exactly the conditions mentioned. The books which have appeared on this subject are the following:

1. Strauss-Durckheim, H. Anatomie descriptive et comparative du Chat. 2 vols. Paris, 1845.

2. Mivart, St. George. The Cat: an Introduction to the Study of Back-boned Animals, especially Mammals. New York, 1881.

3. Wilder, Burt G., and Gage, Simon H. Anatomical Technology as applied to the Domestic Cat. New York, 1882.

4. Gorham, F. P., and Tower, R. W. A Laboratory Guide for the Dissection of the Cat. New York, 1895.

5. Jayne, H. Mammalian Anatomy. Vol. I. Philadelphia, 1898.

The first of these works treats only of the muscles and bones, and is not available for American students. Its excellent plates (or Williams’s outline reproductions of the same) should be in every laboratory.

The second book named is written in such general terms that its descriptions are not readily applicable to the actual structures found in the dissection of the cat, and experience has shown that it is not fitted for a laboratory handbook. It contains, in addition to a general account of the anatomy of the cat, also a discussion of its embryology, psychology, palæontology, and classification.

The book by Wilder and Gage professedly uses the cat as a means of illustrating technical methods and a special system of nomenclature. While of much value in many ways, it does not undertake to give a complete account of the anatomy of the animal.

The fourth work is a brief laboratory guide.

The elaborate treatise by Jayne, now in course of publication, is a monumental work, which will be invaluable for reference, but is too voluminous to place in the hands of students. At present only the volume on the bones has been published.

As appears from the above brief characterization, none of these books gives a complete description of the anatomy of the cat in moderate volume and without extraneous matter. This is what the present work aims to do.

In the year 1891-92, Professor Reighard prepared a partial account of the anatomy of the cat, which has since been in use, in typewritten form, in University of Michigan classes. It has been used also at the Universities of Illinois, Nebraska, and West Virginia, and in Dartmouth College, and has proven so useful for college work in Mammalian Anatomy that it was decided to complete it and prepare it for publication. This has been done by Dr. Jennings.

The figures, which are throughout original, are direct reproductions of ink drawings, made under the direction of Dr. Jennings by Mrs. Jennings.

The book is limited to a description of the normal anatomy of the cat. The direct linear action of each muscle taken alone has been given in the description of muscles; other matters belonging to the realm of physiology, as well as all histological matter, have been excluded. It was felt that the monumental work of Jayne on the anatomy of the cat, now in course of publication, forms the best repository for a description of variations and abnormalities, so that these have been mentioned in the present volume only when they are so frequent as to be of much practical importance.

Except where the contrary is stated, the descriptions are based throughout on our own dissections and observations and are in no sense a compilation. For this reason we have not thought it necessary to collect the scattered references to the anatomy of the cat that may occur in the literature. A collection of such references may be found in Wilder and Gage’s _Anatomical Technology_. In addition to the works already referred to, we have of course made use of the standard works on human and veterinary anatomy. Among these should be mentioned as especially useful the _Anatomie des Hundes_ by Ellenberger and Baum. Other publications which have been of service in the preparation of the work are Windle and Parson’s paper _On the Myology of the Terrestrial Carnivora_, in the Proceedings of the Zoological Society of London for 1897 and 1898, T. B. Stowell’s papers on the nervous system of the cat in the Proceedings of the American Philosophical Society (1881, 1886, 1888) and in the Journal of Comparative Neurology (vol. I.), and F. Clasen’s _Die Muskeln und Nerven des proximalen Abschnitts der vorderen Extremität der Katze_, in Nova Acta der Ksl. Leop.-Carol. Deutschen Akademie der Naturforscher, Bd. 64.

_Nomenclature._--The question of nomenclature has been one of difficulty. What is desired is a _uniform_ set of anatomical names,--a system that shall be generally used by anatomists. At present the greatest diversity prevails as to the names to be applied to the different structures of the body. The only set of terms which at the present time seems to have any chance of general acceptance is that proposed by the German Anatomical Society at their meeting in Basel in 1895, and generally designated by the abbreviation BNA. This system has therefore been adopted, in its main features, for use in the present work. It seems impossible at the present time, however, to impose any one set of terms absolutely upon anatomists of all nations, and we have felt it necessary to use for certain familiar structures, in place of the BNA terms, names that have come to have a fixed place in English anatomy, and may almost be considered component parts of the English language. The German anatomists have expressly recognized the fact that this would be to a greater or less degree necessary among anatomists of different nations, and have characterized their list as for the present tentative, and capable of farther development. The only purpose of a name is that it shall furnish a key to a common understanding; where the BNA name does not furnish such a key to English readers, and where there is a term in established English usage that does serve this purpose and seems unlikely to be supplanted, we have used the latter. But we have endeavored to make the number of these exceptions as small as possible, and in such cases we have usually cited at the same time the term proposed by the German society, followed by the abbreviation BNA. When, on the other hand, we have adopted a BNA term for which there is also a commonly used English equivalent, the latter has likewise usually been cited in parenthesis.

In deciding whether or not to use in a given case the BNA term many difficult cases arose. Will the common English name _innominate_ bone (os innominatum) be replaced by the BNA term _os coxæ_ or _coxal bone_? We have held this to be highly improbable, and have therefore used the term _innominate bone_, merely citing _os coxæ_ (BNA) as a synonym. In the same way we have used _centrum_ as a designation of a part of a vertebra, in place of _corpus_ (BNA); _premaxillary_ bone or _premaxilla_ in place of _os incisivum_ (BNA); _malar_ bone in place of _os zygomaticum_ (BNA); _trapezoid_ as a name of one of the bones of the carpus, in place of _os multangulum minus_ (BNA), etc. In other cases where it has seemed probable that the BNA term would come into common use, though now unfamiliar, this and the more common English expression are both used or used alternatively; such has been the case, for example, with the Gasserian ganglion or semilunar ganglion (BNA). In naming the cerebral sulci and gyri the system in use for man is not well fitted for bringing out the plan of those in the brain of the cat, so that it was necessary to reject the BNA names for these structures.

As to the use of the Latin terms and their equivalents in English form, we have made a practice of employing in the text sometimes one, sometimes the other; this has the advantage of giving variety, and of impressing the interchangeability of the Latin and English forms on the mind of the student. Where a given structure is called by two equally well-known names, we have used both, holding that the student should become familiar with each and recognize their identity of meaning.

In general we have maintained the principle that the primary purpose of such a work as the present is not to illustrate or defend any particular system of nomenclature, but to aid in obtaining a knowledge of the structures themselves. With this end in view, we have used such terms as would in our judgment best subserve this purpose, making the BNA system, as the one most likely to prevail, our basis. In applying the system we have had to keep in mind a number of sometimes conflicting principles. In some cases the judgment of other anatomists will doubtless differ from our own; but this we feel to be inevitable. The matter of an absolutely uniform nomenclature is not ripe for settlement at the present time.

Some further explanation is needed in regard to the topographical terms, or terms of direction, used in the present work. We have adopted the BNA terms in this matter also. The terms _superior_, _inferior_, _anterior_, and _posterior_ have been avoided, as these terms do not convey the same meaning in the case of the cat as they do in man, owing to the difference in the posture of the body. In place of these terms are used _dorsal_ and _ventral_, _cranial_ and _caudal_. As terms of direction these, of course, must have an absolutely fixed meaning, signifying always the same _direction_ without necessary reference to any given structure. For example, _cranial_ means not merely toward the _cranium_, but refers to the _direction_ which is indicated by movement along a line from the middle of the body, toward the cranium; after the head or cranium is reached, the term still continues in force for structures even beyond the cranium. Thus the tip of the nose is considered to be _craniad_ of the cranium itself. _Lateral_ signifies away from the middle plane; _medial_ toward it. _Inner_ and _outer_ or _internal_ and _external_ are used only with reference to the structure of separate organs, not with reference to the median plane of the body.

In describing the limbs the _convexity_ of the joint (the elbow or knee) is considered as _dorsal_, the concavity being therefore ventral. _Medial_ refers to that side of the limb which in the normal position is toward the middle of the body; _lateral_ to the outer side. Terms of direction which are derived only from the structure of the limb itself are in some cases more convenient than the usual ones. In the fore limbs the terms _radial_ (referring to the side on which the radius lies) and _ulnar_ (referring to the side on which the ulna lies) are used; in the hind limbs the terms _tibial_ and _fibular_ are used in a similar manner. _Distal_ means toward the free end of a limb or other projecting structure; _proximal_, toward the attached end.

For all these terms an adverbial form ending in _-ad_ has been employed. Experience has shown this to be very useful in practice, and while not expressly recommended by the BNA, it is not condemned. Terms ending in _-al_ are therefore adjectives; those ending in _-ad_ are adverbs.

In compounding these terms of direction, the hyphen has been omitted in accordance with the usage recommended by the Standard Dictionary. Thus _dorsoventral_ is written in place of _dorso-ventral_, etc. The student will perhaps be assisted in understanding these compounds if he notes that the first component always ends in _-o_, so that the letter _o_ practically serves the purpose of a hyphen in determining how the word is to be divided.

In one particular the BNA nomenclature is not entirely consistent. While recommending or at least permitting the use of the general terms _dorsal_ and _ventral_ in place of the human _posterior_ and _anterior_, and _cranial_ and _caudal_ in place of _superior_ and _inferior_, it retains the words _anterior_, _posterior_, _superior_, and _inferior_ as parts of the names of definite organs. For example, we have the muscle _serratus anterior_ in place of _serratus ventralis_; _serratus posterior inferior_ in place of _serratus dorsalis caudalis_. This is very unfortunate, from a comparative standpoint, but we have felt it necessary to retain the BNA terms in order that the structures of the cat may receive the same names as the corresponding structures of man.

In the matter of orthography we have endeavored to follow the best English anatomical usage, as exemplified in Gray’s _Human Anatomy_,--therefore writing _peroneus_ in place of _peronæus_, _pyriformis_ in place of _piriformis_, etc.

The book is designed for use in the laboratory, to accompany the dissection and study of the structures themselves. Anatomy cannot be learned from a book alone, and no one should attempt to use the present work without at the same time carefully dissecting the cat. On the other hand, anatomy can scarcely be learned without descriptions and figures of the structures laid bare in dissection, so that this or some similar work should be in the hands of any one attempting to gain a knowledge of anatomy through the dissection of the cat.

The figures have all been drawn from actual dissections, and have been carefully selected with a view to furnishing the most direct assistance to the dissector. It is hoped that no figures are lacking that are required for giving the students the necessary points of departure for an intelligent dissection of any part of the body. The fore limb is illustrated somewhat more fully than the hind limb, because it was thought that the fore limb would usually be dissected first; the hind limb will be easily dissected, with the aid of the figures given, after the experience gained in dissecting the fore limb.

As the book is designed to accompany the dissection of the specimen in the laboratory, it was deemed best to give succinct specific directions for the dissection of the different systems of organs, together with suggestions as to methods of preserving and handling the material. These are included in an appendix.

CONTENTS.

PAGE THE SKELETON OF THE CAT 1

I. The Vertebral Column 1 Thoracic Vertebræ 1 Lumbar Vertebræ 7 Sacral Vertebræ: Sacrum 8 Caudal Vertebræ 11 Cervical Vertebræ 11 Ligaments of the Vertebral Column 16

II. The Ribs 18

III. The Sternum 20

IV. The Skull 21 Occipital Bone 22 Interparietal 25 Sphenoid 25 Presphenoid 29 Temporal 30 Parietal 36 Frontal 37 Maxillary 39 Premaxillary 41 Nasal 42 Ethmoid 42 Vomer 44 Palatine 45 Lachrymal 46 Malar 47 Mandible 47 Hyoid 49 The Skull as a Whole 49 Cavities of the Skull 57 Joints and Ligaments of the Skull 61

V. The Thoracic Extremities 62 Scapula 62 Clavicle 64 Humerus 64 Radius 67 Ulna 68 Carpus 69 Bones of the Hand 71 Joints and Ligaments of the Thoracic Limbs 73

VI. The Pelvic Extremities 76 Innominate Bones 76 Femur 79 Patella 80 Tibia 80 Fibula 82 Tarsus 82 Bones of the Foot 85 Joints and Ligaments of the Pelvic Limbs 86

THE MUSCLES 93

I. Muscles of the Skin 93

II. Muscles of the Head 96 _A._ Superficial Muscles 96 _B._ Deep Muscles 107 _a._ Muscles of Mastication 107 _b._ Muscles of Hyoid Bone 112

III. Muscles of the Body 115 1. Muscles of the Back 115 _A._ Muscles of the Shoulder 115 _B._ Muscles of the Vertebral Column 123 _a._ Muscles of the Lumbar and Thoracic Region 126 _b._ Dorsal Muscles of the Cervical Region 131 _C._ Muscles of the Tail 136 2. Muscles on the Ventral Side of the Vertebral Column 138 _A._ Lumbar and Thoracic Regions 138 _B._ Muscles on the Ventral Side of the Neck 139 3. Muscles of the Thorax 144 _A._ Breast Muscles (Connecting the Arm and Thorax) 144 _B._ Muscles of the Wall of the Thorax 148 4. Abdominal Muscles 153

IV. Muscles of the Thoracic Limbs 156 1. Muscles of the Shoulder 156 _A._ Lateral Surface 156 _B._ Medial Surface 161 2. Muscles of the Brachium or Upper Arm 164 3. Muscles of the Antibrachium or Forearm 172 Fascia of the Forearm 172 _A._ Muscles on the Ulnar and Dorsal Side of the Forearm 173 _B._ Muscles on the Radial and Ventral Side of the Forearm 179 4. Muscles of the Hand 184 _A._ Between the Tendons 184 _B._ Muscles of the Thumb 184 _C._ Between the Metacarpals 185 _D._ Special Muscles of the Second Digit 185 _E._ Special Muscles of the Fifth Digit 185

V. Muscles of the Pelvic Limbs 186 1. Muscles of the Hip 186 _A._ On the Lateral Surface of the Hip 186 Fascia of the Thigh 186 _B._ On the Medial Surface of the Hip 192 2. Muscles of the Thigh 194 3. Muscles of the Lower Leg 203 _A._ On the Ventral Side 203 _B._ On the Dorsal and Lateral Surfaces 209 4. Muscles of the Foot 212 _A._ Muscles on the Dorsum of the Foot 212 _B._ Muscles on the Sole of the Foot 212 _C._ Muscles of the Tarsus 215

THE VISCERA 217

I. The Body Cavity 217

II. Alimentary Canal 221 1. Mouth 221 Glands of the Mouth 223 Teeth 224 Tongue 226 Muscles of the Tongue 228 Soft Palate 229 Muscles of the Soft Palate 230 2. Pharynx 231 Muscles of the Pharynx 232 3. Œsophagus 234 4. Stomach 234 5. Small Intestine 236 6. Large Intestine 237 7. Liver, Pancreas, and Spleen 239