A rotator cuff injury is the most frequent cause of shoulder pain due to strain and tear in the muscles or tendons of the shoulder. The rotator cuff is made of four muscles that surround and stabilize the shoulder, including the supraspinatus, infraspinatus, teres minor and subscapularis. These muscles form a “cuff” around the head of the humerus, giving us range of motion in our shoulder while also creating stability. The shoulder joint is one of two ball and socket joints, the other being the hip joint. While the hip has less motion and more stability, the shoulder is opposite and has more motion and less stability. This makes the shoulder more prone to injury.
The main causes of rotator cuff injury include repetitive shoulder movement, overloading of the joint by heaving lifting, an accident such as a fall, poor posture, and general wear and tear with age. Injuries can also be secondary to impingement, subacromial bone spurs, and poor blood supply. Rotator cuff injuries are very common in athletes and occupations that require overhead and repetitive activities. The most common tendon to be affected with rotator cuff injury is the supraspinatus tendon, located on the top part of the shoulder. A rotator cuff injury can include tendon inflammation, partial tendon tears or complete tendon tears.
Symptoms associated with a rotator cuff injury include pain and tenderness in the shoulder, weakness of the shoulder, pain when sleeping on the affected side, numbness and tingling in the affected hand and arm, and restricted shoulder movement.
To diagnosis a rotator cuff injury, your doctor will usually ask you a series of questions about your symptoms, examine you and do specific arm movements to see if these cause difficulty and pain. In some cases, imaging such as x-ray, ultrasound or MRI might be required.