Shoulder abduction is a movement that involves raising the arm away from the body. This action primarily occurs at the shoulder joint, where the humerus moves upward and outward. It typically starts when the arm is at the side and can be performed to various angles, usually up to 90 degrees or more, depending on flexibility and strength. The primary muscles involved in shoulder abduction include the deltoid and the supraspinatus. These muscles work together to lift the arm, making this movement essential for many daily activities, such as reaching for objects or lifting items overhead.