Rotator Cuff 101
The rotator cuff is a combination of four muscles (supraspinatus, infraspinatus, teres minor and subscapularis) which originate on the scapula (shoulder blade) and attach to the humeral head (upper arm). The purpose of the rotator cuff is to stabilize the shoulder joint and to position the upper arm in space.
Injuries to the rotator cuff can lead to shoulder pain and limitation in shoulder motion. The rotator cuff can be injured after a traumatic event such as a fall on an outstretched arm or an attempt to lift a heavy object. A rotator cuff injury may also occur as a result of "wear and tear" over time without a specific traumatic event.
Symptoms associated with an injury to the rotator cuff include pain, usually localizing to the outside (or lateral) aspect of the shoulder, pain in the shoulder with overhead activities and a feeling of weakness in the shoulder. Pain may radiate up into the neck or down the outer portion of the arm to the elbow. A classic symptom of rotator cuff pathology is night pain, or pain that awakens one from sleep, especially after rolling over onto the affected shoulder.
The diagnosis of a rotator cuff injury necessitates a thorough history and physical examination. The location of pain, severity of pain, weakness, associated symptoms such as numbness or tingling, neck pain and history of trauma or prior shoulder surgery are all important factors to be considered in accurately diagnosing a rotator cuff injury. A detailed physical examination can rule out other possible causes of shoulder pain such as arthritis, capsulitis (stiff or "frozen" shoulder), shoulder blade bursitis, biceps tendonitis or herniated (bulging) disc in the neck. Tests such as X-rays or magnetic resonance imaging (MRI) may be necessary to help determine the cause of shoulder pain.