Gluteus maximus muscle

At a glance

English

Gluteus maximus muscle

Latin (TA2)

Musculus gluteus maximus

System

Muscle

Region

Lower limb

Side

Paired, left and right

About the gluteus maximus muscle

The gluteus maximus is the largest and most superficial of the gluteal muscles and gives the buttock its rounded bulk. It is a thick, roughly four-sided sheet whose coarse fascicles run parallel, grouped into bundles by fibrous partitions. Beneath it lie gluteus medius and minimus, the deep lateral rotators and the sciatic nerve as it leaves the pelvis.

The muscle takes a wide origin along the back of the pelvis: the outer surface of the ilium behind the posterior gluteal line and the adjoining part of the iliac crest, the back of the lower sacrum and the coccyx beside it, the sacrotuberous ligament, the thoracolumbar fascia, and the gluteal aponeurosis covering gluteus medius. Its fibres slope downward and outward. Most of them, including the upper part and the superficial lower fibres, pass over the greater trochanter into the iliotibial tract of the fascia lata; the deep lower fibres fix to the femur at its gluteal tuberosity. Bursae ease its movement over the greater trochanter, the ischial tuberosity and the vastus lateralis tendon.

Its main job is powerful hip extension: climbing stairs, rising from a chair or straightening up after bending forward, when it pulls the pelvis back over the thighs together with the hamstrings and adductor magnus. Working from below, it holds the pelvis and trunk steady on the femoral head, most clearly when standing on one leg. Through the iliotibial tract it tenses the fascia lata and steadies the extended knee. Its lower fibres also rotate the thigh laterally and adduct it, while the upper fibres help abduct the hip.

Its size is a distinctive human feature tied to upright posture and bipedal walking. Clinicians test it with functional tasks such as repeated sit-to-stand, and its upper outer part is a common site for intramuscular injection because that quadrant lies well away from the sciatic nerve.

Attachments, action and supply

Origin

Outer ilium behind the posterior gluteal line and the nearby iliac crest, dorsal lower sacrum and coccyx, thoracolumbar fascia, sacrotuberous ligament and gluteal aponeurosis.

Insertion

Mostly into the iliotibial tract of the fascia lata; the deep lower fibres onto the femoral gluteal tuberosity.

Action

Extends the hip and laterally rotates the thigh; steadies the pelvis on the femur, tenses the iliotibial tract, and its upper fibres assist abduction while its lower fibres assist adduction.

Nerve supply

Inferior gluteal nerve (L5, S1, S2).

Blood supply

Superior and inferior gluteal arteries, with contributions from the first perforating branch of the profunda femoris.