What structure is made up of the supraspinatus, infraspinatus, teres minor, deltoid, and subscapularis muscles?

• A. Shoulder capsule
• B. Rotator cuff
• C. Brachial plexus
• D. Joint capsule

Answer: (B)

The structure composed of the supraspinatus, infraspinatus, teres minor, deltoid, and subscapularis muscles is known as the rotator cuff. The rotator cuff is a collection of muscles and their tendons that stabilize the glenohumeral joint (shoulder joint) and allow for a wide range of shoulder movements. Each of these muscles plays a specific role in shoulder motion and stability.

The supraspinatus initiates arm abduction, the infraspinatus and teres minor are primarily responsible for lateral rotation of the humerus, and the subscapularis facilitates medial rotation. Together with the deltoid, they form a protective chamber around the shoulder joint, keeping the humeral head securely in the shallow glenoid cavity of the scapula. This arrangement is crucial for maintaining the integrity and function of the shoulder, especially during activities that require arm movement.

The shoulder capsule and joint capsule are terms often used interchangeably to refer to the fibrous connective tissue that surrounds the shoulder joint, but they do not specifically describe the group of muscles responsible for movement and stabilization like the rotator cuff does. The brachial plexus, on the other hand, is a network