obturator internus (muscle)

ob·tu·ra·tor in·ter·nus (mus·cle)

[TA]
intrapelvic muscle extending into gluteal region; origin, pelvic surface of obturator membrane and margin of obturator foramen; insertion, passes out of pelvis through lesser sciatic foramen, in so doing, making a 90° turn to insert into the medial surface of greater trochanter; action, rotates thigh laterally; nerve supply, nerve to obturator internus (sacral plexus).