Which muscle is primarily responsible for external rotation of the hip?

• A. Gluteus medius
• B. Psoas major
• C. Tensor fasciae latae
• D. Gluteus maximus

Answer: (A)

External rotation of the hip involves turning the thigh outward around the hip joint. The gluteus medius has posterior fibers that pull the femur into external rotation, especially as the hip extends, making it the most effective external rotator among the muscles listed. The psoas major mainly flexes the hip, the tensor fasciae latae tends to flex and medially rotate, and the gluteus maximus is a powerful extender with an external-rotation role that becomes more prominent when the hip is fully extended. Because the posterior fibers of the gluteus medius actively drive outward rotation in common hip positions, it best explains the external rotation action here.