The rotator cuff muscles are important in shoulder movements and in maintaining glenohumeral joint (shoulder joint) stability. These muscles arise from the scapula and connect to the head of the humerus forming a cuff at the shoulder joint. They hold the head of the humerus in the small and shallow glenoid fossa of the scapula. The glenohumeral joint is often likened to a golf ball(head of the humerus) sitting on a golf tee(glenoid fossa). During abduction of the arm, the rotator cuff compresses the glenohumeral joint in order to allow the large deltoid muscle to further elevate the arm. In other words, without the rotator cuff, the humeral head would ride up partially out of the glenoid fossa, lessening the efficiency of the deltoid muscle. During flexion of the arm infraspinatus and subscapularis act as joint stabilizers. During extension subscapularis and supraspinatus help stabilize the shoulder joint. Subscapularis stabilizes the joint during external rotation.
Rotator cuff tear
Main article: Rotator cuff tear
The tendons at the ends of the rotator cuff muscles can become torn, leading to pain and restricted movement of the arm. A torn rotator cuff can occur following a trauma to the shoulder or it can occur through "wear and tear" of the tendons (most commonly that of the supraspinatus) under the acromion. It is an injury frequently sustained by athletes whose duties involve making repetitive throws, such as baseball pitchers, American football quarterbacks, volleyball (due to their swinging motions), water polo players, swimmers, boxers, kayaking, fast bowlers in cricket, and tennis players (due to their service motion). This type of injury also commonly affects conductors (music), choral conductor, orchestral conductor, due to the swinging motions and other movements used to lead their ensemble. It is commonly associated with motions that require repeated overhead motions or forceful pulling motions.
 Rotator cuff impingement
A systematic review of relevant research found that the accuracy of the physical examination is low. The Hawkins-Kennedy test has a sensitivity of approximately 80% to 90% for detecting impingement. The infraspinatus and supraspinatus tests have a specificity of 80% to 90%.
 Reduce pain and swelling
As with all muscle injuries, R.I.C.E. is the modality recommended by physicians, DOs, physical therapists, athletic trainers, and chiropractors.
Rest means ceasing movement of the affected area.
Icing uses ice to reduce inflammation.
Compression limits the swelling.
Elevation involves placing the area higher to reduce inflammation and swelling.
Cold compression therapy is very useful for all muscle tears and strains as it reduces pain and swelling. Using a cold compression therapy wrap for 15 minutes before sleeping can aid in reducing the pain that causes restless sleep.
The rotator cuff can be strengthened to rehabilitate shoulder injuries, and prevent future ones. There are different exercises to target the individual rotator cuff muscles