The =femoral= (or anterior crural) nerve (N. femoralis) is derived
chiefly from the fourth and fifth lumbar nerves, but commonly receives a
fasciculus from the third nerve also (Fig. 524). It is the larger of the
two nerves which are given off from the anterior part of the
lumbo-sacral plexus. It runs backward at first between the psoas major
and minor, then crosses the deep face of the tendon of insertion of the
latter, and descends under cover of the sartorius in the furrow between
the two heads of the iliacus. It gives off the saphenous nerve, crosses
the lower part of the outer head of the iliacus, and divides into
several branches which dip into the interstice between the rectus
femoris and the vastus internus (Fig. 450). These branches are
accompanied by the anterior femoral vessels and innervate the quadriceps
femoris. Collateral muscular branches are supplied to the ilio-psoas and
sartorius.
The =saphenous nerve= (N. saphenus) (Figs. 450, 451, 457) is given off
as the parent trunk crosses the furrow between the psoas major and the
outer head of the iliacus. It descends with the femoral vessels in the
femoral canal, and gives branches to the sartorius, gracilis, and
pectineus. About the middle of the thigh it divides into several
branches which emerge from between the sartorius and gracilis, perforate
the deep fascia and ramify on the inner surface and the front of the
limb as far downward as the hock. The longer posterior branches
accompany the saphenous vessels, while the anterior branches deviate
forward toward the stifle and the anterior surface of the leg.