The obturator internus laterally rotates and abducts the femur at the hip joint and is innervated by the nerve to the obturator internus.
The gemellus superior and inferior (gemelli is Latin for “twins”) are a pair of triangular muscles associated with the upper and lower margins of the obturator internus tendon (Fig. 6.45):
The base of the gemellus superior originates from the gluteal surface of the ischial spine.