Piriformis muscle

Piriformis muscle
Buttocks seen from behind (the piriformis and the rest of the lateral rotator group are visible)
Muscles of the gluteal and posterior femoral regions seen from the front
Details
Origin	Sacrum
Insertion	Greater trochanter
Artery	Inferior gluteal, lateral sacral and superior gluteal artery,
Nerve	Nerve to the piriformis (L5, S1, and S2)
Actions	External rotator of the thigh
Identifiers
Latin	musculus piriformis
TA98	A04.7.02.011
TA2	2604
FMA	19082
Anatomical terms of muscle [edit on Wikidata]

The piriformis muscle (from Latin piriformis 'pear-shaped') is a flat, pyramidally-shaped muscle in the gluteal region of the lower limbs. It is one of the six muscles in the lateral rotator group.

The piriformis muscle has its origin upon the front surface of the sacrum, and inserts onto the greater trochanter of the femur. Depending upon the given position of the leg, it acts either as external (lateral) rotator of the thigh or as abductor of the thigh. It is innervated by the piriformis nerve.