Final answer:
The four rotator cuff muscles that stabilize and move the GH joint are the supraspinatus, infraspinatus, teres minor, and subscapularis.
Step-by-step explanation:
The four muscles on the scapula that help with movement and stabilization of the glenohumeral (GH) joint are known as the rotator cuff muscles. These include the supraspinatus, which abducts the arm; the infraspinatus, which laterally rotates the arm; the teres minor, which also assists in lateral rotation and extension of the arm; and the subscapularis, which medially rotates the arm. These muscles originate from the scapula and attach to the greater or lesser tubercles of the humerus. As they cross the shoulder joint, their tendons encircle the head of the humerus and fuse with the anterior, superior, and posterior walls of the articular capsule, forming the rotator cuff. This structure provides the primary support for the shoulder joint and allows the muscles to serve as dynamic ligaments, which is essential for the movement and stabilization of the GH joint.