What does external rotation involve?

External rotation refers to the movement of a joint in a way that turns a body part away from the midline of the body. This action occurs at various joints, including the shoulder and hip. For example, when the arm is at the side and rotated outward, that is external rotation; the arm moves away from the center of the body.

Understanding this movement is essential for fields like sports medicine, as it helps in analyzing body mechanics, rehabilitation exercises, and injury prevention strategies. The other options describe different types of movements: rotating towards the midline indicates internal rotation, while moving parts upward or downward describes elevation and depression, respectively. Each of these movements has its own specific anatomical definitions and implications in physical therapy and athletic training.