« AnteriorContinuar »
PECULIARITIES IN THE ANATOMY AND PHYSIOLOGY OF THE DOG.
The Skeleton including the Teeth.— The Muscular System.—The Brain and
Nervous System.- The Digestive System.- The Heart and Lungs.-- The Skin.
THE SKELETON*, INCLUDING THE TEETH.
In the skeleton of the dog and in that of the horse, as well as of all other animals remarkable for their speed, there is a peculiar formation of the chest which deserves to be noticed. The principle of construction in every thorax, as this part is called scientifically, is that of dilatation and contraction, by which its entire contents are lessened or increased, and thereby air is made to pass in and out. In man this is chiefly caused by the front of the chest rising and falling, and in this way increasing the diameter from before backwards, but in the dog, horse, deer, &c., the increase is from side to side, the ribs being sickle-shaped, and acting laterally like the gill-covers of a fish. From this it often arises that a narrow-chested horse or dog may have better wind than another with a round barrel, because he is able to alter the cubic contents of his chest more rapidly, and thus inspire and expire a larger volume of air. A round barrel is nearly at its greatest expansion, and though it can contract it cannot dilate its volume, while the chest that is too flat can expand rapidly, but then it
a, a, a. The ligamentum nuchæ.
22, 22. Twenty caudal vertebræ verteI. II. III. IV. V. VI. VII. The seven ver
bræ of the tail. tebræ of the neck.
23. The left os innominatum. 13. The thirteen dorsal vertebræ.
24. Right ditto. 7. The seven lumbar vertebræ.
The nine true ribs, with their cartilages. 21. Os sacrum, or rump-bone.
The four false ribs, with their cartilages. 0,0. The sternum.
THE LEFT ANTERIOR EXTREMITY.
1. The scapula, or shoulder-blade.
11. Os metacarpi digiti quarti fourth 2. Os humeri, or arm-bone.
metacarpal. 3. Radius—the lesser bone of the arm. 12. Os metacarpi digiti quinti. 4. The elbow, or olecranon process of 13, 13, 13, 13. The first phalanges of the the ulna.
fore feet. 7. Os pisiforme, or pisiform bone.
14, 14, 14, 14. The second ditto. 10. Os metacarpi digiti tertii — the third 15. The third ditto. metacarpal bone.
16. The sesamoid bone.