Shoulder impingement syndrome is an umbrella term that describes the painful pinching of soft tissue between the shoulder’s ball-and-socket joint (glenohumeral joint) and acromion. It results from swelling of the soft tissue in the shoulder.
A reduction in joint space caused by shoulder osteoarthritis or from the swelling caused by shoulder bursitis may lead to shoulder impingement syndrome. Frozen shoulder is a condition with symptoms very similar to shoulder impingement.
Shoulder impingement syndrome and the irritation that it causes to components such as bursa and tendons may also lead to the development of arthritic conditions in the shoulder. With modern medical imaging, physicians can typically pinpoint a more exact diagnosis of a shoulder condition.