What is the role of the supraspinatus muscle in shoulder movement?

The supraspinatus muscle plays a critical role in shoulder movement by initiating shoulder abduction. It is one of the four rotator cuff muscles and is primarily responsible for lifting the arm away from the body. Specifically, it helps to raise the arm during the first 15 degrees of abduction before other muscles, like the deltoid, take over for further movement.

During shoulder abduction, the supraspinatus stabilizes the glenohumeral joint by keeping the head of the humerus centered in the glenoid cavity, which is essential for smooth movement and preventing dislocation. The precise action of this muscle is vital in various activities that require raising the arm, such as reaching or lifting.

In contrast, the other provided choices do not accurately reflect the primary function of the supraspinatus. It does not facilitate shoulder flexion, provide stability during shoulder hiking, or allow deep shoulder rotation. Understanding the specific function of the supraspinatus helps clarify its importance in shoulder mechanics and overall upper limb mobility.