Rotation describes a turning movement of a body part around its own longitudinal axis. In anatomy, a distinction is made between internal rotation (towards the middle of the body) and external rotation (away from the middle of the body).
In the shoulder joint, internal and external rotation are controlled by parts of the rotator cuff. In the hip joint, the small external rotators such as the piriformis muscle take on this task, among others. In the spine, rotation is generated across segments by the abdominal, back and neck muscles and is required for many everyday movements.