tendon, and reflected on to the navicular bone and the interosseous
ligament of the pedal joint. This will be of particular interest when we
come to deal with cases of pricked foot from picked up nails. Above, it is
in connection with the synovial membrane of the pedal articulation and that
of the metacarpo-phalangeal sheath.

_Action_.--The action of the perforans is to flex the third on the second,
and the second on the first phalanx. The latter it flexes in turn on the
metacarpus. It also assists in the flexion of the entire foot on the
forearm, and in supporting the angle of the metacarpo-phalangeal
articulation when the animal is standing.


D. THE ARTERIES.

So far as the arteries supplying the foot are concerned, we shall be
interested in following up the distribution of the two digitals, which are
the terminal branches of the Large Metacarpal.

THE LARGE METACARPAL, OR COLLATERAL ARTERY OF THE CANNON.--This, the larger
terminal branch of the posterior radial artery, needs brief mention, for
the reason that we shall be afterwards concerned with it in the operation
of neurectomy. Its point of origin is the inside of the inferior extremity
of the radius. Descending in company with the flexor tendons, and passing
behind the carpus and beneath the carpal sheath, it continues its descent,
in company with the internal plantar nerve and the internal metacarpal
vein, on the inner side of the flexor tendons until just above the fetlock.
At this point it bifurcates into the digital arteries.

From the carpus downwards the large metacarpal artery, the internal