A torn rotator cuff is a common injury causing weakness and instability of the shoulder. Your shoulder is made up of the scapula (shoulder blade), the clavicle (collar bone) and the humerus (long bone of the upper arm). The head of the humerus fits into a small depression in the scapula called the glenoid; it is held in place by the rotator cuff, which is composed of four different muscles that come together to form a network of tendons surrounding the head of the humerus. The bursa is a sac that lubricates the bone and allows the tendons to glide freely. When a rotator cuff is torn, this means that one or more of the tendons that hold the head of the humerus in place within the scapula are damaged. This often starts by fraying of the tendon (partial tear), progressing to complete tearing in some cases (full-thickness tear).
Acute tears may occur when you lift a heavy object in an abrupt fashion or fall on an outstretched arm. Traumatic rotator cuff injuries can also occur in association with other injuries, such as a dislocated shoulder or a fractured clavicle.
Wear and tear
More often, rotator cuff tears occur as a process of wearing down of the affected tendon, as may be associated with aging. Bone spurs caused by arthritis, repetitive stress and decreased blood supply to the rotator cuff tendon are all risk factors for this type of injury.
Symptoms of rotator cuff damage include: pain even at rest (i.e. lying on the affected shoulder), pain upon lifting or lowering the affected arm, a cracking or popping sound (crepitus) when rotating the shoulder and weakness in the affected arm. Tendons that are torn as the result of trauma may cause severe immediate pain and weakness of the affected arm.
Non-surgical treatment consists of rest, immobilization, physical therapy and possibly cortisone injections to reduce inflammation. When non-surgical interventions fail, surgery to reattach the affected tendon to the head of the humerus may be recommended.