The sciatic nerve (S. N) is composed of fibers from L4. L5. S1. S2 and S3. The anterior primary rami of these spinal nerve converge and split into anterior and posterior divisions. The trunk formed by the posterior divisions gives off the superior and inferior gluteal nerves and proceeds toward the sciatic notch as the common peroneal part of the sciatic nerve. The trunk formed by the anterior divisions becomes the tibial part of the sciatic nerve and also proceeds toward the notch. This sciatic nerve (largest nerve in the body) emerges from the pelvis through the lower part of the greater sciatic foramen. The nerve appears below piriformis muscle and curves downward and laterally. Lying successively on the root of the ischial spine, the superior gemellus, the obturator internus, the infenor gemellus, and the Quadratun femoris to reach the back of the adductor magnus muscle. It’s related posteriorly to the posterior cutanous nerve of thing and the gluteus maximus. It leaves the buttock region by passing deep to the long head of the biceps femoris to enter the back of the thing. The sciatic nerve usually gives no branches in the gluteal region. In the thing it is overlapped posteriorly by the adjacent margins of the biceps femoris and semimembranosus muscle. It lies on the posterior aspect of the adductor magnus muscle. In the lower third of the thing it ends by dividing into the tibial and common peroneal nerves. Occasionally the sciatic nerve divides into its two terminal parts at a higher level in the upper part of the thing, the gluteal regions or even inside the pelvis.