Your rotator cuff is made up of the muscles and tendons in your shoulder. These muscles and tendons connect your upper arm bone with your shoulder blade. They also help hold the ball of your upper arm bone firmly in your shoulder socket. The combination results in the greatest range of motion of any joint in your body.
A rotator cuff injury includes any type of irritation or damage to your rotator cuff muscles or tendons. Causes of a rotator cuff injury may include falling, lifting and repetitive arm activities — especially those done overhead, such as throwing a baseball or placing items on overhead shelves.
About half of the time, a rotator cuff injury can heal with self-care measures or exercise therapy.
Rotator cuff injury signs and symptoms may include:
Pain and tenderness in your shoulder, especially when reaching overhead, reaching behind your back, lifting, pulling or sleeping on the affected side
Loss of shoulder range of motion
Inclination to keep your shoulder inactive
The most common symptom is pain. You may experience it when you reach up to comb your hair, bend your arm back to put on a jacket or carry something heavy. Lying on the affected shoulder also can be painful. If you have a severe injury, such as a large tear, you may experience continuous pain and muscle weakness.
Four major muscles (subscapularis, supraspinatus, infraspinatus and teres minor) and their tendons connect your upper arm bone (humerus) with your shoulder blade (scapula). A rotator cuff injury, which is fairly common, involves any type of irritation or damage to your rotator cuff muscles or tendons, including:
Tendinitis. Tendons in your rotator cuff can become inflamed due to overuse or overload, especially if you’re an athlete who performs a lot of overhead activities, such as in tennis or racquetball.
Bursitis. The fluid-filled sac (bursa) between your shoulder joint and rotator cuff tendons can become irritated and inflamed.
Strain or tear. Left untreated, tendinitis can weaken a tendon and lead to chronic tendon degeneration or to a tendon tear. Stress from overuse also can cause a shoulder tendon or muscle to tear.
Common causes of rotator cuff injuries include:
Normal wear and tear. Increasingly after age 40, normal wear and tear on your rotator cuff can cause a breakdown of fibrous protein (collagen) in the cuff’s tendons and muscles. This makes them more prone to degeneration and injury. With age, you may also develop calcium deposits within the cuff or arthritic bone spurs that can pinch or irritate your rotator cuff.
Poor posture. When you slouch your neck and shoulders forward, the space where the rotator cuff muscles reside can become smaller. This can allow a muscle or tendon to become pinched under your shoulder bones (including your collarbone), especially during overhead activities, such as throwing.
Falling. Using your arm to break a fall or falling on your arm can bruise or tear a rotator cuff tendon or muscle.
Lifting or pulling. Lifting an object that’s too heavy or doing so improperly — especially overhead — can strain or tear your tendons or muscles. Likewise, pulling something, such as a high-poundage archery bow, may cause an injury.
Repetitive stress. Repetitive overhead movement of your arms can stress your rotator cuff muscles and tendons, causing inflammation and eventually tearing. This occurs often in athletes, especially baseball pitchers, swimmers and tennis players. It’s also common among people in the building trades, such as painters and carpenters.