73 - superior gluteal nerve

The superior gluteal nerve is a nerve that originates in the pelvis which supplies the gluteus medius, the gluteus minimus, and the tensor fasciae latae muscles.

Structure

The superior gluteal nerve originates in the sacral plexus. It arises from the dorsal divisions of the fourth and fifth lumbar and first sacral nerves. It leaves the pelvis through the greater sciatic foramen above the piriformis, accompanied by the superior gluteal artery and the superior gluteal vein. It then divides into a superior and an inferior branch.

• The superior branch accompanies the upper branch of the deep division of the superior gluteal artery and ends in the gluteus minimus.
• The inferior branch runs with the lower branch of the deep division of the superior gluteal artery across the gluteus minimus; it gives filaments to the gluteus medius and minimus, and ends in the tensor fasciae latae.

The superior gluteal nerve and vessels travel above the piriformis muscle through the greater sciatic foramen; the inferior gluteal nerve and vessels travel below the muscle.

Pathology

In normal gait, the small gluteal muscles on the stance side can stabilize the pelvis in the coronal plane. Weakness or paralysis of these muscles caused by a damaged superior gluteal nerve can result in a weak abduction in the affected hip joint. This gait disturbance is known as Trendelenburg gait. In a positive Trendelenburg test the pelvis sags toward the normal unsupported side (the swing leg). The opposite, when the pelvis is elevated on the swing side, is known as Duchenne limp. Bilateral loss of the small gluteal muscles results in a waddling gait.