Acromioclavicular joint cyst - Geyser sign

Case contributed by Maulik S Patel
Diagnosis almost certain

Presentation

Swelling overlying the acromioclavicular joint for 6 months, pain and restricted shoulder movements.

Patient Data

Age: 70 years
Gender: Female

Visible swelling above the acromioclavicular (AC) joint.

Non-visualization of the long head biceps tendon.

Thin and abnormal echopattern of the subscapularis tendon.

Acromiohumeral distance of 3 mm (Normal is >6 mm).

Supraspinatus and infraspinatus muscles bellies show significant volume loss and fatty infiltration.

Case Discussion

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.

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