Notes on Veterinary Anatomy

by Charles James Korinek

2. Cervical Vertebrae or Neck Bones.—These bones are seven in number. The first and second bones proceeding from the head receive special names. The first one is called the atlas, from which the head is suspended and to which it is attached; it somewhat resembles the body of a bird with wings extended. The second bone receives the name of dentata. This is the bone which allows the head to turn in any direction, hence it is sometimes called the axis or pivot of the neck. Between these two bones, on the upper surface, is the only place where the spinal cord is not covered with bone, a spot about three-fourths of an inch in diameter. The next four bones receive no name, and are about the same in size and length. The last, or the seventh bone, is only about one half the length of the preceding ones and receives no special name.

3. Dorsal Vertebrae or Back-Bone.—Dorsal bones are eighteen in number. The chief point of interest about them are the height of the spines on the upper surface of the bones. These large spines form the withers of the horse, as will be noticed in the skeleton. On either side of these bones the ribs are attached, 18 pairs corresponding with the number of bones in this region.

4. Lumbar Vertebrae (or the bones which form the skeleton of the loins). These bones are six in number, and they are situated immediately above the kidneys.

5. Sacral Vertebrae or Rump Bones.—There are five of these bones in the young horse, but in the adult they unite as a single bone, somewhat triangular-shape. These are situated between the upper hip bones and help to form the rump. Beneath these bones the bladder is situated.

6. Coccygeal Vertebrae or Tail Bones.—These are 18 to 20 in number. There is no complete canal, like in the previous vertebraes, for enclosure of the spinal cord.

7. Pelvic or Hip Bones.—The pelvic bones are flat, but somewhat irregularly-shaped, and they form the sides, floor, and part of the roof of the pelvic cavity. Above they are connected with the sacrum, and below united to each other, in the adult, by ossification (union of bone). In the young animal, as above stated, and especially in the foetus, each side consists of three parts, which retain their names of ilium, ischium, and pubis, even after union by ossification. They all three meet in the acetabulum, or articular cavity for the femur or hip bone.

8. Sternum or Breast Bone.—This bone is small and short in the horse and is situated on the lower surface of the chest cavity. The principle points to be noted in this bone are that of its softness, and that the first eight pairs of ribs are attached to it on either side. This bone, in the horse resembles the keel and cut-water of a boat.

9. Ribs.—In the horse the ribs usually number eighteen on each side. They extend in a series of arches of varying curvature from the dorsal vertebrae above, towards the sternum and sides of the abdomen below. Their shape, in a great measure, determines the conformation or shape of the thorax or chest cavity; they protect its contents, and materially aid in its contraction and expansion. They are continued downward and forward by a small piece of cartilage or gristle, and are just slightly attached to the breast bone or sternum; these are called the false ribs. Note that, starting with the first rib, they get longer until the ninth rib is reached; they then get shorter, the last rib being only a few inches long.

10. Scapula or Shoulder Blade.—The scapula is a flat bone situated on the antero-lateral (front side) surface of the thorax or chest cavity, it is triangular in shape, the base being turned upwards. The inferior or lower extremity articulates with the humerus or shoulder bone.

11. Humerus or Shoulder Bone.—The humerus is a long bone extending from the scapula to the radius and ulna in an oblique direction downwards and backwards. Like all long bones it possesses a shaft and two extremities and two articular surfaces.