Sciatic Nerve

Abstract

Despite its long course from the sacrum to the popliteal region, the sciatic nerve is only susceptible to an entrapment neuropathy as it leaves the pelvis passing over the lower rim of the sciatic notch. The nerve is derived from vertebral levels L4–S3. Its peroneal component (L4–S2) merges with its tibial counterpart (L4–S3) distal to the lower lumbar intervertebral and upper sacral foramina, and on the posterior wall of the pelvis. As it passes through the sciatic notch, the nerve usually lies below the piriformis muscle. It continues distally between the lesser trochanter of the femur and the ischial tuberosity. Below this level, the course of the sciatic nerve is uncomplicated. It divides into its tibial and common peroneal branches at the upper margin of the popliteal fossa.