The obturator internus muscle, like the piriformis muscle, is both a muscle of the pelvic wall and of the gluteal region. It originates within the pelvis, and continues as a flattened tendon posteriorly through the lesser sciatic foramen (between ischial spine and tuberosity).
- anterolateral wall of true pelvis
- deep surface of obturator membrane and pelvic surfaces of pubis and ischium
- insertion: medial side of greater trochanter of femur
- laterally rotates the extended femur at hip joint
- abducts the flexed femur at hip joint
- arterial supply: inferior gluteal artery
- innervation: nerve to the obturator internus