Which muscles are primarily responsible for glenohumeral stability?

The rotator cuff muscles are primarily responsible for glenohumeral stability due to their unique anatomical positioning and function. This group comprises four muscles—the supraspinatus, infraspinatus, teres minor, and subscapularis—that encircle the shoulder joint. They play a crucial role in stabilizing the humeral head within the shallow glenoid cavity of the scapula during arm movements.

These muscles work by providing dynamic stability, meaning they maintain joint congruity and proper alignment while allowing for a full range of motion. Their ability to engage and contract actively enables them to counteract forces that may lead to dislocations or instability, particularly when the arm is raised or moved in various directions. The rotator cuff is essential for both the stability and mobility of the shoulder, making it vital for various overhead activities and sports.

In contrast, other muscle groups, while playing roles in shoulder movement or posture, do not primarily contribute to the stabilization of the glenohumeral joint in the same way the rotator cuff does.