Findings of chronic rotator cuff tear:

1. nonvisualization of supraspinatus and infraspinatus tendon. Retraction more than 30-35 mm
2. significant fatty infiltration and volume loss of supraspinatus and infraspinatus muscle bellies
3. acromiohumeral distance 3 mm, which should be more than 6 mm (basically a radiographic measurement)

Due to absent tendons, the deltoid pulls the humeral head up. The humeral head repeated strikes the undersurface of the acromion and acromioclavicular joint. There is sclerosis of the undersurface of the acromion and tearing of the inferior acromioclavicular ligament. Joint fluid escapes into the acromioclavicular joint. Later on there is a tear of the superior acromioclavicular ligament. Joint fluid escapes into subcutaneous tissues, producing swelling. This called the Geyser phenomenon.