The Shoulder Joint
The shoulder is a ball and socket joint. The arm bone (humerus) ends in a ball shaped surface (humeral head) that fits into a very shallow socket (glenoid). This socket is part of the wingbone (scapula). This shallow socket allows the shoulder joint tremendous range of motion.
The Rotator Cuff
The rotator cuff is a group of four muscles which rotate the humerus and hold the shoulder in place by keeping the humeral head in the proper position inside the glenoid socket. These muscles allow everyday repetitive motions like scratching behind your head or back, painting, waxing, using hand tools, reaching, and lifting overhead. They are used extensively in athletic activities like throwing a ball, serving a tennis ball and driving a golf ball.
Rotator Cuff Injuries
Injuries to the rotator cuff are very common. Typical symptoms of a rotator cuff tear include pain, weakness, and loss of shoulder range of motion. However, a significant number of tears cause no symptoms. There is little medical consensus for what treatment is best and there is large geographic variation in surgical rates.
Pain is frequently not a good predictor of injury severity, but does indicate that an injury is likely. (Ref)
Both non-operative and operative treatment can be effective. A visit to a qualified health care provider is a must to make a proper diagnosis. Once a diagnosis is made, treatment options can be discussed.