fore-arm contains distinct bones called the radius
and the ulna. The corresponding region in the horse seems at first
to possess but one bone. Careful observation, however, enables us to
distinguish in this bone a part which clearly answers to the upper end
of the ulna. This is closely united with the chief mass of the bone
which represents the radius, and runs out into a slender shaft which may
be traced for some distance downwards upon the back of the radius, and
then in most cases thins out and vanishes. It takes still more trouble
to make sure of what is nevertheless 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