Origin Internal surface of obturator membrane and posterior bony margins of obturator foramen Insertion Medial surface of greater trochanter of femur, in common with superior and inferior gemelli Action Rotates the thigh laterally; also helps abduct the thigh when it is flexed Innervation Nerve to the obturator internus and superior gemellus -- a branch of the sacral plexus (L5, S1) (L5, S1) Arterial Supply Internal pudendal and superior and inferior gluteal arteries