ss the fact, that a small part of the
lower end of the bone of the horse's fore-arm, which is only distinct in
a very young foal, is really the lower extremity of the ulna.

What is commonly called the knee of a horse is its wrist. The "cannon
bone" answers to the middle bone of the five metacarpal bones, which
support the palm of the hand in ourselves. The "pastern," "coronary,"
and "coffin" bones of veterinarians answer to the joints of our middle
fingers, while the hoof is simply a greatly enlarged and thickened nail.
But if what lies below the horse's "knee" thus corresponds to the middle
finger in ourselves, what has become of the four other fingers or
digits? We find in the places of the second and fourth digits only two
slender splint-like bones, about two-thirds as long as the cannon-bone,
which gradually taper to their lower ends and bear no finger joints, or,
as they are termed, phalanges. Sometimes, small bony or gristly nodules
are to be found at the bases of these two metacarpal splints, and it is
probable that these represent rudiments of the first and fifth toes.
Thus, the part of the horse's skeleton which corresponds with that of
the human hand contains one overgrown middle digit, and at least two
imperfect lateral digits; and these answer, respectively, to the third,
the second, and the fourth fingers in man.

Corresponding modifications are found in the hind limb. In ourselves,
and in most quadrupeds, the leg contains two distinct bones, a large
bone, the tibia, and a smaller and more slender bone, the fibula. But in
the horse, the fibula seems, at first, to be reduced to its upper end; a
short slender bone united with the tibia, and ending in a point below,
occupying its place. Examination of the lower end of a young foal's
shin-bone, however, shows a distinct portion of osseous matter, which
is the lower end of the fibula; so that the apparently single lower end
of the shin-bone is really made up of the coalesced ends of the tibia
and fibula, just as the apparently single lower end of the fore-arm bone
is composed of the coalesced radius and ulna.

The heel of the horse is the part commonly known as the hock. The hinder
cannon-bone answers to the middle metatarsal bone of the human foot, the
pastern, coronary, and coffin bones, to the middle toe bones; the hind
hoof to the nail, as in the fore-foot. And, as in the fore-foot, there
are merely two splints to represent the second and the fourth toes.