Quadratus femoris muscle

At a glance

English

Quadratus femoris muscle

Latin (TA2)

Musculus quadratus femoris

System

Muscle

Region

Lower limb

Side

Paired, left and right

About the quadratus femoris muscle

Quadratus femoris is a flat, four-sided muscle deep in the buttock, the lowest of the short lateral rotators of the hip. It lies below the inferior gemellus and above the upper border of adductor magnus, and its upper and lower edges run almost horizontally, so the three muscles sit edge to edge. It is covered by gluteus maximus, and the sciatic nerve passes down across its back.

It arises from the outer edge of the ischial tuberosity, just in front of the origins of the hamstrings. The fibres pass directly outwards and end on the quadrate tubercle, a small raised area on the intertrochanteric crest at the back of the upper femur, and on the vertical line running down from it. A bursa often separates the front of the muscle from the lesser trochanter, which lies just deep to it.

The muscle is a strong lateral rotator of the thigh, and it can also help adduct the hip. Like the other short rotators, it steadies the head of the femur in the acetabulum. It is supplied by the nerve to quadratus femoris, a sacral plexus branch that also serves the inferior gemellus and the hip joint, and its blood comes mainly from the medial circumflex femoral artery, with help from the inferior gluteal artery. Terminal branches of the medial circumflex femoral vessels emerge between its lower edge and adductor magnus, a gap used by surgeons as a guide.

Because a branch of the medial circumflex artery runs close to it, and because that vessel supplies much of the femoral head, the muscle has been used as a vascular pedicle graft to bring blood to a femoral head at risk of losing its supply. In ischiofemoral impingement, the narrow space between the ischium and the lesser trochanter squeezes the muscle, causing deep buttock or groin pain; imaging then shows oedema in the muscle. Strain or inflammation at its insertion is another, often missed, source of groin pain.

Attachments, action and supply

Origin

Outer edge of the ischial tuberosity.

Insertion

Quadrate tubercle of the femur's intertrochanteric crest and the line below it.

Action

Laterally rotates and assists adduction of the thigh; stabilises the hip by holding the femoral head in its socket.

Nerve supply

Nerve to quadratus femoris (L4, L5, S1).

Blood supply

Medial circumflex femoral artery, with the inferior gluteal artery.