What is the primary role of the supraspinatus muscle?

The primary role of the supraspinatus muscle is to initiate shoulder abduction. This muscle is part of the rotator cuff group and is situated on the superior aspect of the scapula. Its specific function includes abduction of the arm, especially during the initial 15-30 degrees of shoulder elevation.

When the arm is abducted, the supraspinatus pulls on the greater tubercle of the humerus, helping to lift the arm away from the body. This action is vital for many everyday tasks and activities, making the supraspinatus crucial for optimal shoulder function.

Other options like forearm flexion, shoulder internal rotation, and elbow extension do not accurately represent the primary function of the supraspinatus and instead pertain to different muscle groups or different joints entirely.