24 
THE VETERINARY SCIENCE 
cavity. The principal points to be noted in this bone are that it 
is the softest one in the horse, and that the first eight pairs 
of ribs are attached to it on either side. This bone, in the 
horse, resembles a small, flat boat. 
12. Ribs. — There are eighteen pairs of ribs. They form 
the lateral wall of the thorax or chest cavity and afford pro- 
tection to the heart and lungs. They are attached above to 
the dorsal region of the back bone ; below, the first eight pair 
are attached to the sternum, or breast bone; these are called 
the true ribs of the horse ; the next ten pair are not attached 
to the sternum below, the lower ends being free. They are 
continued downward and forward by a small piece of carti- 
lage or gristle, and are just slightly attached to the breast 
bone; 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. 
13. Number of Bones in the Skeleton of a Horse. — 
Thirty-eight bones are found in the head of a colt, not includ- 
ing the teeth, but in after life a great many bones become 
attached to each other by a process called ossification. 
Head 38 
Spinal column 54 
Pelvic cavity or hips, three pair or six single 6 
Ribs, eighteen pair 36 
Breast 1 
Both front legs 42 
Both hind legs 38 
Ear, bones very small and unimportant, 3 in each ear. . 6 
Total, not including the teeth 221 
The teeth are dealt with separately in Chapter XV. 
