Postural Restoration Institute Practice Test

External rotation torque at the hip comes from muscles that have a favorable line of pull around the femoral neck and are positioned to rotate the thigh outward when the pelvis is stabilized. The gluteus maximus is the dominant external rotator when the hip is in extension, giving a strong, leverage-rich pull to turn the thigh outward and to help maintain posterior pelvic tilt. The obturator externus wraps around the deep aspect of the hip and provides a powerful lever for external rotation across a range of hip positions, making it another key external rotator in functional tasks. The psoas, while best known as a hip flexor, contributes to rotational control as well in certain postures where the pelvis is stabilized and the femur can rotate externally; in combined hip-fixation positions used in PRI concepts, it supports the external rotation mechanism alongside the other two muscles. Other muscles listed are not as consistently powerful external rotators across common postural positions. For example, gluteus medius and gluteus minimus are more classic abductors with some rotational action, and the piriformis/gemelli set are deep external rotators but don’t typically impart the same robust external rotation torque as the trio described in this context.