How should the arm be positioned during external rotation of the shoulder?

During external rotation of the shoulder, the arm is positioned in a way that allows the humerus to rotate outward away from the body. This movement involves the external rotators of the shoulder, primarily the infraspinatus and teres minor muscles. Positioning the arm externally helps to properly visualize the shoulder joint and surrounding structures during imaging, as it aligns the scapula and provides clear visualization of the glenohumeral joint space. This orientation is crucial for accurate diagnosis and treatment planning, as it can reveal potential pathologies such as rotator cuff injuries or impingement that might not be visible in other positions.