The rotator cuff is the name for a group of four small muscles and their tendons that surround the shoulder joint. This oft-injured muscle group plays an essential role in the normal function of the shoulder.
Anatomy
The shoulder joint is classified as a "ball-in-socket" joint. That classification conjures an image of a ball nestled securely in the confines of a sturdy socket. In the case of the shoulder joint, the ball of the humerus, or arm bone, is quite large in relation to the small, shallow socket of the scapula, or shoulder blade. The relation is more like a golf ball resting on a tee. This configuration allows the shoulder joint to have a tremendous range of motion at the relative expense of structural stability. Although large muscles of the chest and back attach to the humerus, the small, short rotator cuff muscles surround the ball of the humerus and anchor it to the "tee" of the scapula.
Function
As the name suggests, the rotator cuff muscles facilitate rotation movements of the shoulder. Of equal importance is the stabilizing role of the rotator cuff. While larger and stronger muscles are responsible for the reaching, pushing and pulling movements of the shoulder, the rotator cuff muscles work to hold the ball of the humerus in position on the shallow surface of the scapula's socket. In the absence of a normally functioning rotator cuff, even moderate efforts by the larger shoulder muscles would be sufficient to dislocate the ball from the socket.
Injury
Symptoms of a rotator cuff injury, according to the American Academy of Orthopedic Surgeons, typically include pain in the front of the shoulder that radiates down the side of the arm. It may hurt to sleep on the affected side. There may be weakness in the arm and tasks, such as fastening a bra or combing the hair may become difficult. In young persons, the rotator cuff is usually injured from a direct blow, a fall or a sports trauma. In people older than the age of 40, injury more often results from repetitive trauma, typically associated with the arm being used in an overhead position.
Treatments
For tendon inflammation or partial tears of the rotator cuff, physical therapy is usually recommended. In cases where there is a large tear to the rotator cuff, especially if there is significant weakness in raising the arm, surgery is advisable according to Dr. James Dreese, of the University of Maryland Medical Center. Large tears do not have the potential to mend properly without surgical intervention. Physical therapy also plays an important role after surgery. Initial efforts are to restore mobility in the shoulder. Later, resistance exercises are introduced to restore strength. This process can take many months.
Prevention
The National Institutes of Health recognizes that being older than age 40 and participating in sports or activities that involve repetitive motion overhead are risk factors for developing rotator cuff injuries. Although aging is not preventable, steps can be taken to reduce the impact of the other risk factors. Using a ladder when appropriate can reduce the effects of overhead reaching while performing certain tasks. Warming up thoroughly before sports participation and being diligent about maintaining strength and flexibility through proper exercise can help reduce the likelihood of sustaining a sports-related injury.
