-
Anatomy:
- origin: anterior surface of sacrum between and lateral to anterior sacral foramen, capsule of sacroiliac articulation, margin of the
greater sciatic foramen,
and sacrotuberous ligament;
-
insertion: superior border of greater trochanter of femur;
- action: external rotation of hip & abducts thigh at the hip;
- nerve supply: sacral plexus, L5, S1, S2;
- synergists: superior and inferior gemellus, quadratus femoris, internal obturator and external obturator;
Piriformis syndrome. 
