The =plantar nerves=, internal and external (N. plantaris medialis,
lateralis), result from the bifurcation of the tibial nerve in the lower
part of the leg (Figs. 458, 459). They continue at first in the same
direction and relations as the parent trunk, in direct apposition and
inclosed in a common sheath. At the hock they diverge at a very acute
angle and descend in the tarsal canal behind the deep flexor tendon in
company with the plantar arteries. The internal plantar nerve supplies
cutaneous nerves to the inner aspect of the tarsus and metatarsus,
descends along the inner border of the flexor tendons behind the
superficial plantar metatarsal vessels, and is otherwise arranged like
the corresponding volar nerve of the fore limb. The external plantar
nerve deviates outward between the two flexor tendons to reach their
outer border. It supplies a branch to the suspensory ligament, and in
its further course resembles the corresponding nerve of the fore limb.
In so-called “tibial” neurectomy the operator really cuts the two
plantar nerves which have not yet separated. The anastomotic branch
between the two plantar nerves is smaller than that which connects the
corresponding nerves of the fore limb, and is absent in 30 per cent.
of the cases, according to Rudert.