Name
Pronunciation
(piri-FOR-mus)
Origin/Proximal Attachment
Pelvic surface of sacrum
Insertion/Distal Attachment
Medial surface of greater trochanter (through greater sciatic foramen)
Action/Relevance
Externally rotates the thigh when extended
Abducts thigh when flexed
Innervation
Nerve to piriformis (S1, 2)
Notes
Lies in the same plane as glut medius
Often fuses its insertion with ob internus and the gemelli.