The piriformis muscle is a flat, pyramidal to pear-shaped skeletal muscle that belongs to the group of deep hip muscles and is innervated via the Sacral plexus (L5-S2)[^1].
Anatomy
The piriformis muscle originates by several slips from the pelvic surface of the Sacrum, lateral to the anterior sacral foramina and from the margin of the greater sciatic notch. It passes through the greater sciatic foramen and inserts on the inner aspect of the apex of the greater trochanter.
Function
In standing, the piriformis muscle acts as an external rotator and abductor and contributes to retroversion.