Gluteus maximus is the largest muscle in the body and forms the bulk of the buttock on each side. It arises from several contiguous sites:
- external surface of ilium posterior to the posterior gluteal line
- posterior third of iliac crest
- lumbar fascia
- lateral mass of the sacrum
- sacrotuberous ligament
Passing inferolaterally, it inserts into two contiguous structures:
- the majority of fibres insert into the iliotibial tract; this passes inferiorly to insert into the anterior surface of the lateral tibial condyle
- a minority of fibres insert into the gluteal tuberosity on the posterior, superior third of the femur
Gluteus maximus is innervated by the inferior gluteal nerve (L5-S2).
Its actions are varied:
- main extensor of the thigh at the hip
- lateral rotation of thigh at the hip
- facilitates knee extension via the iliotibial tract
It is associated with a number of bursae.