The Rotator Cuff is a group of muscles and their tendons that connecting the humerus (upper arm) to the scapula (the shoulder blade). The four muscles of the rotator cuff are:

1. Musculus Supraspinatus – The supraspinatus abducts, or elevates, the shoulder joint.
2. Musculus Infraspinatus – The infraspinatus externally rotates the shoulder joint.
3. Musculus Subscapularis – The subscapularis muscle works to depress the head of the humerus allowing it to move freely in the glenohumeral joint during elevation of the arm
4. Musculus Teres minor – The teres minor muscle externally rotates the shoulder joint.

The four muscles also stabilize the head of the humerus in the glenohumeral joint, or shoulder joint. The muscles, tendons and other tissues form a cuff around the humerus. The Rotator Cuff tendons provide stability to the shoulder, the muscles allow the shoulder to rotate. (more…)