Inferior gluteal nerve
The inferior gluteal nerve is formed from the posterior divisions of the L5, S1 and S2 nerve roots of the sacral plexus. The nerve is the primary motor nerve that supplies the gluteus maximus muscle.
The inferior gluteal nerve arises from the posterior divisions of the sacral plexus. It is formed from the L5-S2 nerve roots and shortly after forming exits the pelvis through the greater sciatic foramen beneath the lower border of the piriformis muscle and along the posterior aspect of the sciatic nerve.
After exiting the pelvis the inferior gluteal nerve enters the gluteal region and immediately pierces the gluteus maximus muscle at its origin (at the medial end of the muscle).
The course of the nerve within the gluteus maximus muscle is short and it gives no cutaneous branches. The inferior gluteal nerve pierces the deep surface of the gluteus maximus muscle along the inferior third of the muscle and ramifies extensively to supply both the muscle and hip capsule.
The inferior gluteal nerve is closely related to the sciatic nerve to which it is medial and posterior as it exits the pelvis inferior to the piriformis muscle.
Variations of the inferior gluteal nerve have been noted in several cadaveric studies. The inferior gluteal nerve has been shown to emerge from the suprapiriform foramen in 1-4% of cadavers studied. Furthermore, case series indicate that the inferior gluteal nerve may perforate the piriformis muscle to access the gluteus maximus muscle typically with the common peroneal nerve. It was noted that this variation was more common in women than in men.
A posterior approach to the hip in surgical procedures may result in damage to the inferior gluteal nerve either by dissection of the nerve or by stretching and retraction of the nerve. Evidence suggests that the risk of damage to the inferior gluteal nerve increases when an incision exceeds 5 cm from the tip of the greater trochanter of the femur across the gluteus maximus muscle towards the posterior superior iliac spine.