d between the extensor longus pollicis, and
extensor communis tendons, the former being taken as a guide for the
incision. In passing the ligature around this vessel at either of these
situations, care is required to avoid including the venae comites and
the accompanying nerve.

The sole of the foot is covered by a hard and thick integument, beneath
which will be seen a large quantity of granulated adipose tissue so
intersected by bands of fibrous structure as to form a firm, but elastic
cushion, in the situations particularly of the heel and joints of the
toes. On removing this structure, we expose the plantar fascia, B, Plate
68, Figure 1, extending from the os calcis, A, to the toes. This fascia
is remarkably strong, especially its middle and outer parts, which serve
to retain the arched form of the foot, and thereby to protect the
plantar structures from superincumbent pressure during the erect
posture. The superficial plantar muscles become exposed on removing the
plantar fascia, to which they adhere. In the centre will be seen the
thick fleshy flexor digitorum brevis muscle, B, arising from the
inferior part of the os calcis, and passing forwards to divide into four
small tendons, b b b b, for the four outer toes. On the inner side of
the foot appears the abductor pollicis, D, arising from the inner side
of the os calcis and internal annular ligament, and passing to be
inserted with the flexor pollicis brevis, H, into the sesamoid bones and
base of the first phalanx of the great toe. On the external border of
the foot is situated the abductor minimi digiti, C, arising from the
outer side of the os calcis, and passing to be inserted with the flexor
brevis minimi digiti into the base of the first phalanx of the little
toe. When the flexor brevis digitorum muscle is removed, the plantar
arteries, L M, and nerves, are brought partially into view; and by
further dividing the abductor pollicis, D, their continuity with the
posterior tibial artery and nerves, K L, Plate 67, Figure 1, behind the
inner ankle may be seen.

The plantar branches of the posterior tibial artery are the internal and
external, both of which are deeply placed between the superficial and
deep plantar muscles. The internal plantar artery is much the smaller of
the two. The external plantar artery, L, Plate 68, Figure 1, is large,
and seems to be the proper continuation of the posterior tibial. It
corresponds, in the foot, to the deep palmar arch in