The quadratus femoris muscle is an important muscles that provides stabilisation in the hip joint. The size of the muscle can be measured by the golden standard MRI and MSK ultrasound. MSK ultrasound is less expensive and easily feasible. The anterior and medial muscle groups measured with MSK ultrasound is valid. The quadratus femoris muscle is yet not examined according to the literature. During the measurement there can be include if there’s par example a muscle tear, the therapy can be made patient specific.