The piriformis (also piriformis muscle, latin: musculus piriformis) is a small skeletal muscle located in the gluteal region.
The piriformis originates in the lesser pelvis from the anterior surface of sacrum.
The piriformis exits the lesser pelvis through the greater sciatic foramen and inserts at the great trochanter.
The major functions of the piriformis are adduction and external rotation of the femur.
The piriformis is innervated by the muscular branches of the sacral plexus.