Shoulder > Rotator Cuff Tear

What is the Rotator Cuff?

The rotator cuff consists of four muscles (supraspinatus, infraspinatus, teres minor, and subscapularis) that originate at the shoulder blade and attach to the ball of the shoulder joint. The four rotator cuff muscles coalesce to form one continuous tissue that resembles the "cuff" of a shirt sleve. It controls the rotation of the ball-shaped head of the upper arm bone (humerus) in the shoulder socket and keeps the ball centered in the socket as it is rotating. The top of the shoulder is called the acromion. Between the acromion and the rotator cuff muscles is lubricated tissue, called the bursa sac, which cushions and decreases friction in the shoulder.

When force is applied to the shoulder or the shoulder is raised over the head, the rotator cuff squeezes against the top of the shoulder, compressing the bursa sac. This pinching of the tendons and muscles, called impingement, causes a condition called bursitis. This irritation in the bursa leads to inflammation and damage in the rotator cuff as muscles and tendons grind in the shoulder joint. Wear and tear to the rotator cuff may first cause slight muscle pulls or mild strains. As this process proceeds, frank tearing of the rotator cuff may occur. Depending on the amount of strain put on the shoulder, rotator cuff tendons may be partially torn (partial thickness rotator cuff tear) or completely ruptured (full thickness rotator cuff tear).

Overuse, especially in people who engage in repeated overhead motions, commonly causes rotator cuff tears. Excessive or traumatic force also can cause rotator cuff tears that develop quickly. Trying to catch a heavy falling object or lifting heavy weights with your arms straight can cause what is called an acute traumatic rotator cuff tear. Contact sports like boxing, wrestling, and football also can cause acute tears.

Some rotator cuff tears, particularly partial tears in young people, may not cause much pain and not require surgery. The initial treatment is often rest, ice, and anti-inflammatory medication to control pain. But complete tears in the rotator cuff that hinder you from raising your arm usually require surgery.

There usually are three parts to an orthopedic evaluation: medical history, a physical examination, and tests that your doctor may order.

Your physician likely will ask about your activities, which may be causing the pain in your shoulder. He will probably ask when the soreness or pain began. If you have had any prior shoulder injuries, your physician will ask about treatments you have tried in the past. You may be asked about your work environment to determine if any continuous overhead activities are causing your pain. Physicians also typically ask about other conditions, such as arthritis, diabetes, and allergies, and medications currently being taken. You may also be asked about your physical and athletic goals – information that will help your physician decide what treatment might be best for you in achieving those goals.

Your physician usually presses on many different areas of the shoulder and tries to pinpoint your pain. Your shoulder may be lifted and rotated in many directions to determine its range of motion. If your doctor can move your arm in a normal range of motion but you cannot do the same on your own, you may have a rotator cuff tear. The following physical tests may help your doctor check the strength of specific rotator cuff muscles:

   Subscapularis lift-off test – With your arm rotated behind your back and your elbow flexed, you try to push away against resistance. Inability to push away signals injury to the subscapularis muscle.

   Supraspinatus test – Your arms are held straight out at shoulder height with your thumbs pointing down. You attempt to hold your arms at shoulder height while your doctor presses your arms down. If you cannot hold your arms up, your supraspinatus muscle has a weakness.

Your doctor also may perform other tests to determine if you have rotator cuff impingement, which is a pinching of the tendons and the protective bursa sac; or shoulder instability, a general condition where the upper arm bone is not held securely in the socket.

Should your doctor need to take a closer look, the following tests may be ordered:

   X-rays are used to check for bone spurs or for abnormal alignment of the bones in the shoulder blade that could be pinching the rotator cuff. X-rays also may reveal calcium deposits, which can harden rotator cuff muscles and tendons.

   Arthrograms can reveal tears in rotator cuff tissues. A dye is injected into the shoulder joint and X-rays are taken. If the dye leaks out into the bursa, a tear is confirmed.

   MRI (magnetic resonance imaging) can create images with magnetic waves that help doctors look at tendons in the rotator cuff.

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