Quadratus Femoris

Gluteal & Hip · Lower Limb

Located in the Gluteal & Hip of the Lower Limb, the Quadratus Femoris is a key muscle for anatomy study. Originating at Lateral border of ischial tuberosity, it inserts at Quadrate tubercle on intertrochanteric crest of femur. It is responsible for several movements: Lateral rotation of hip; stabilizes femoral head in acetabulum. Innervation is provided by the Nerve to quadratus femoris (L4, L5, S1).

Origin, Insertion, Action & Nerve

Origin

Lateral border of ischial tuberosity

Insertion

Quadrate tubercle on intertrochanteric crest of femur

Action

Lateral rotation of hip; stabilizes femoral head in acetabulum

Nerve

Nerve to quadratus femoris (L4, L5, S1)

Attachments explained

The Quadratus Femoris is defined first by where it attaches. Its origin is the more fixed anchor, usually the proximal or more stable end that stays put during contraction, while its insertion is the more mobile point that is pulled toward the origin when the muscle shortens.

Origin

Lateral border of ischial tuberosity

Insertion

Quadrate tubercle on intertrochanteric crest of femur

Action & function

When the Quadratus Femoris contracts, it produces the following movements: Lateral rotation of hip; stabilizes femoral head in acetabulum.

As part of the Gluteal & Hip group of the Lower Limb, it works alongside neighbouring muscles to generate smooth, coordinated movement and to stabilise the structures it acts on.

Nerve supply & clinical relevance

The Quadratus Femoris receives its nerve supply from the Nerve to quadratus femoris (L4, L5, S1). This nerve carries fibres from spinal segment(s) L4, L5, S1.

Because a muscle can only contract when its nerve is intact, injury to the Nerve to quadratus femoris or to its spinal roots (L4, L5, S1) can weaken or paralyse the Quadratus Femoris, impairing the movements it normally produces (lateral rotation of hip). This is why knowing the innervation is central to localising nerve lesions in clinical practice.

How to study the Quadratus Femoris (the OIANS method)

OIANS stands for Origin, Insertion, Action and Nerve, the four facts that uniquely define every skeletal muscle. To learn the Quadratus Femoris, work through them in order: picture its origin, trace the muscle to its insertion, reason out the action that shortening between those two points must create, then add the nerve that drives it.

Most students remember the Quadratus Femoris fastest by linking its action back to its attachments rather than memorising each fact in isolation. Once the origin and insertion make sense, the action usually follows logically.