Distal terminal branches are Tibial nerve and Common peroneal nerve.Muscular branches supplies hamstring muscle and ischial part of adductor magnus.Articular branches arise proximally to supply the hip joint through its posterior capsule, which sometimes may arises from sacral plexus.
The nerve can be represented on the back of the thigh by a line drawn from just medial to the midpoint of the line from the ischial tuberosity to the apex of greater trochanter down to the apex of popliteal fossa. The tibial nerve is derived from the anterior divisions of the sacral plexus, and the common fibular nerve is made up of the posterior divisions of the plexus. Prior to diverging, the tibial and common peroneal nerves are structurally separate and only loosely held together as the sciatic nerve. The nerve ends at the upper aspect of the popliteal fossa where it branches to distal nerves (tibial and common peroneal nerve). The nerve is crossed obliquely on its superficial aspect by the long head of Biceps Femoris. Nerves branch off to the hamstring muscles. Descending vertically, it enters the thigh at the lower border of gluteus maximus, where it lies on the posterior surface of Adductor Magnus. The Posterior Femoral Cutaneous Nerve and the Inferior Gluteal Artery lie on its medial side. It passes inferiorly crossing Obturator Internus, the Gemelli Muscles and Quadratus Femoris. Below the piriformis it lies deep to Gluteus Maximus.
Initially deep to piriformis, it runs inferiorly and laterally posterior to the ischium, crossing over the nerve to Quadratus Femoris. It leaves the pelvis through the greater sciatic foramen, inferior to the Piriformis muscle, and descends between the greater trochanter of the Femur and the ischial tuberosity.
It is formed from the ventral rami of the fourth lumbar to third sacral spinal nerves and is a continuation of the upper part of the sacral plexus. At the upper aspect of popliteal fossa, it branches medially to the Tibial Nerve and laterally to the Common Peroneal Nerve. The sciatic nerve is the thickest (approximately 2cm in wide) nerve in the body which travels in the posterior compartment of the thigh and supplies major part of the lower extremity.
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