Muscle
Piriformis
Key landmark of the gluteal region
High-yield
Divides the greater sciatic foramen; sciatic nerve usually exits below it. Lateral rotator of the extended hip.
Overview
A pear-shaped muscle exiting the greater sciatic foramen that laterally rotates the extended thigh and is the central landmark of the gluteal region.
Reference facts
- Origin
Anterior (pelvic) surface of the sacrum
- Insertion
Superior border of the greater trochanter of the femur
- Action
Laterally rotates the extended thigh; abducts the flexed thigh; stabilises the hip
- Innervation
Nerve to piriformis (anterior rami S1, S2)
- Blood supply
Superior and inferior gluteal arteries