Summary Quadratus femoris Origin Lateral margin of obturator ring above ischial tuberosity Insertion Quadrate tubercle and adjacent bone of intertrochanteric crest of proximal posterior femur Action Rotates the hip laterally; also helps adduct the hip Innervation Nerve to the quadratus femoris (L5, S1) Arterial supply Medial circumflex femoral artery, inferior gluteal artery, 1st - 4th perforating arteries, obturator artery, and some superior muscular branches of popliteal artery