A snapping or catching sensation felt along the front of the shoulder can be caused by many different problems. There could be a torn rotator cuff or a torn labrum. The labrum is a fibrous rim of extra cartilage around the otherwise shallow shoulder socket. It helps give the shoulder socket more depth and keeps the round ball at the top of the humerus (upper arm bone) in the socket.
Other possible causes of shoulder snapping include bursitis, tendon tears, bone spurs, or loose pieces of cartilage or bone inside the shoulder joint. In this case report, the authors describe the symptoms, diagnosis, and treatment of shoulder snapping in a 23-year-old weight lifter.
When the weight lifter first went to the Mayo Clinic Sports Medicine Center in Rochester, Minnesota, he had an eight-week history of painful shoulder snapping. The snapping occurred whenever he lifted his arm straight forward with the elbow straight or when he used his left arm in a rowing motion. Both of these movements are important in weight lifting activities, so it wasn’t something he could ignore for long.
When he was examined, the shoulder was stable with no sign of a rotator cuff tear. There were no other disturbing symptoms like numbness, tingling, swelling, or weakness. Rest and activity modification did not alter the symptoms so X-rays and ultrasound imaging tests were ordered.
The imaging studies showed a pocket of fluid over the tendon of the subscapularis muscle. The subscapularis muscle is part of the rotator cuff, so although the rotator cuff wasn’t torn or ruptured, there was evidence of a tendinopathy. Tendinopathy refers to chronic changes in the tendon without active inflammation.
Inflamed tissue was observed around the subcoracoid bursa. The subcoracoid bursa is sandwiched between the subscapularis muscle and the coracoid process. The coracoid process is a hook-shaped piece of bone that comes from the shoulder blade to help stabilize the shoulder. This subcoracoid bursa is separate from the subscapularis bursa.
The subscapularis bursa actually drapes itself over the top of the subscapularis tendon rather than between the subscapularis tendon and nearby bones. The difference in location of these two bursae is seen on imaging studies and helps clearly identify the exact cause of the problem.
Treatment for a chronically inflamed bursa (bursopathy) can be conservative (nonoperative), a steroid injection (invasive but still nonoperative), or surgery. This particular patient chose surgery, which involved removing the affected bursa. He had a short (four-week) postop rehab program and returned to weight lifting three months later. The surgeon called this a rare case of subcoracoid bursitis causing painful shoulder snapping.
The subcoracoid bursa is designed to allow for smooth sliding and gliding of the humeral head as it rotates inside the shoulder socket. The primary function of this bursa is to allow smooth, pain free shoulder rotation.
It’s likely that the weight lifting activities involving overhead shoulder lifts led to a subcoracoid impingement (pinching). The head of the humerus presses up against the soft tissues that form an arch above the humeral head. Any number of things can narrow the space under the arch. In the case of a serious weight lifter, the muscles around the area bulk up, thus decreasing the space available for the bursa.
The symptoms in this case were not the same for a typical case of subcoracoid impingement. That’s why some of the standard tests (e.g., Gerber test, Yokum test) weren’t positive. The repetitive weight lifting exercises built up certain shoulder muscles that altered the way the tendons shifted during some shoulder movements.
The authors presented this patient case because it was a rare shoulder bursitis causing shoulder snapping in an otherwise healthy but athletic adult. Ultrasound imaging gave the best picture of what was going on to cause the problem.
Physicians are advised to consider the possibility of a subcoracoid bursitis as a possible diagnosis in cases of shoulder snapping among athletes, especially overhead weight lifters. The underlying cause could be one of several soft tissue changes contributing to pinching of the tendons and/or pinching of the bursa between the humeral head and the coracoid process.