Origin The posterior cutaneous nerve of the thigh is a branch of the
sacral plexus. It arises from the posterior divisions of the
S1-
S2, and the anterior divisions of
S2-
S3 sacral spinal nerves.
Course It leaves the
pelvis through the
greater sciatic foramen inferior to the
piriformis muscle. It then descends deep to the
gluteus maximus muscle, medial or posterior to the
sciatic nerve, and alongside the
inferior gluteal artery. It descends within the posterior thigh deep to the
fascia lata (the deep fascia of the thigh) and superficial to the
hamstring muscles. It runs over the long head of the
biceps femoris to the back of the knee. It pierces the
fascia lata posterior to the knee. It then accompanies the
small saphenous vein to about the middle of the posterior leg (i.e. lower leg). Its terminal branches communicate with the
sural nerve.
Branches Its branches are all cutaneous, and are distributed to the gluteal region, the perineum, and the back of the thigh and leg. • The
inferior clunial nerves (or gluteal branches), three or four in number, turn upward around the lower border of the
gluteus maximus, and supply the skin covering the lower and lateral part of that muscle. • The
perineal branches are distributed to the skin at the upper and medial side of the
thigh. • The main part to the back of the thigh and leg consists of numerous filaments derived from both sides of the nerve, and distributed to the skin covering the back and medial side of the thigh, the
popliteal fossa, and the upper part of the back of the leg.
Distribution The posterior cutaneous nerve of the thigh provides sensory innervation to most of the posterior surface of the
thigh (upper leg), and the superior part of the posterior surface of the
leg (lower leg), as well as (the inferior part of) the
gluteal region (via
inferior cluneal nerves, derived from anterior rami of S1-S2), and the
perineum (via the perineal branch). == Clinical significance ==