Innervation Tibial division motor semitendinous semimembranous long head biceps femoris sensory innervatton none Peroneal division motor short head of biceps Origin The sciatic nerve originates from lumbosacral plexus L4-S3 tibial division orginates from anterior preaxial branches of L4,L5,S1,S2,S3 peroneal division originates from from postaxial branches of L4,L5,S1,S2 Course Exits sciatic notch runs anterior or deep to piriformis runs posterior or superficial to short external rotators (superior gemellus, inferior gemellus, obturator internus) Posterior leg It then runs down the posterior leg where it breaks into its three main divisions at the level of the mid thigh Terminal branches common peroneal nerve tibial nerve Injury & Clinical Conditions Iatragenic Injury methods to prevent injury routine visual identification not advised in primary THA palpation recommended visual identification is recommened in revision THA hip extension, knee flexion decreases tension on nerve