Hip internal and external rotation are the two ways the hip joint moves. Internal rotation is when the toes of the feet are close to the midline and the heels are away from the midline, while external rotation is the opposite. The patient lies flat on a diagnostic bed with both lower extremities straight, feet close together, but not quite together, and toes pointing vertically upward. In internal rotation, the toes are tilted medially and the heels are tilted laterally. In external rotation, the toes are tilted to the outside and the heels are tilted to the inside. Under normal circumstances, internal rotation can reach 35 degrees and external rotation 45 degrees, and there is no pain or discomfort in the hip joint during internal and external rotation. If there is pain in the hip joint during internal and external rotation, it may be due to bony structural lesions of the hip joint such as hip joint effusion, ischemic necrosis of the femoral head, or it may be due to muscular lesions such as gluteus, vastus tensor fasciae latae muscle, or pyriformis muscle injuries.