The inferior gluteal nerve is the main motor neuron that innervates the gluteus maximus muscle. It is responsible for the movement of the gluteus maximus in activities requiring the hip to extend the thigh, such as climbing stairs. Injury to this nerve is rare but often occurs as a complication of posterior approach to the hip during hip replacement. When damaged, one would develop gluteus maximus lurch, which is a gait abnormality which causes the individual to 'lurch' backwards to compensate lack in hip extension. Anatomy The largest muscle of the posterior hip, gluteus maximus, is innervated by the inferior gluteal nerve. It branches out and then enters the deep surface of the gluteus maximus, the principal extensor of the thigh, and supplies it. Origin The muscle is supplied by the inferior gluteal nerve which arises from the dorsal branches of the ventral rami of the fifth (L5), the first (S1) and second (S2) sacral nerves. The lumbosacral trunk, which is made up of L5 and a small branch of L4, effectively connects the lumbar and sacral plexuses. The lower branches of the L4 and the L5 nerves enter the sacral plexus. The sacral plexus is formed by the lumbosacral trunk, the first to third sacral ventral rami, and part of the fourth, the remainder of the last joining the coccygeal plexus. The sacral plexus is formed in the pelvis in front of the piriformis muscle. The sacral plexus is formed anterior to the piriformis muscle and gives rise to the sciatic nerve, the superior and inferior gluteal nerves, and the pudendal and posterior femoral cutaneous nerves. However, most of the sacral plexus nerves are scarcely recognizable, because they leave the pelvis through the greater sciatic foramen. From the pelvis, the anterior primary branches of the nerves entering the plexus (the first sacral nerve being a particularly large one) and a mass of nerves on the piriformis can be recognized. Course The inferior gluteal nerve leaves the pelvis through the greater sciatic foramen and runs underneath the piriformis muscle. It then divides into muscular branches to supply the gluteus maximus that pass posteriorly into the deep surface of the gluteus maximus muscle. The inferior gluteal nerve is superficial to the sciatic nerve. It has been described as having multiple branches with subsequent innervation of the overlying gluteus maximus. The inferior gluteal nerve entered the deep surface of gluteus maximus very