Obturator Internus Muscle
The obturator internus muscle originates on the medial surface of the obturator membrane, the ischium near the membrane, and the rim of the pubis.
It exits the pelvic cavity through the lesser sciatic foramen.
The obturator internus is situated partly within the lesser pelvis, and partly at the back of the hip-joint.
It functions to help laterally rotate femur with hip extension and abduct femur with hip flexion, as well as to steady the femoral head in the acetabulum.
Read more about Obturator Internus Muscle: Origin and Insertion, Bursa/bands, Addtional Images