Question: the action of the quadratus femoris muscle is?
Answer: The main action of the quadratus femoris muscle is external (lateral) rotation of the thigh. ... When the leg is in the anatomical position, quadratus femoris, pectineus and the inferior fibers of gluteus maximus assist the thigh adductor muscles (adductor longus, magnus and brevis) to adduct the thigh at the hip joint.