The AC Compression Test most directly indicates injury to which structures?

• A. Damage to the AC ligament or to the coracoclavicular ligament
• B. Subacromial bursa
• C. Rotator cuff
• D. Glenoid labrum

Answer: (A)

The technique loads the acromioclavicular joint directly, stressing the stabilizing ligaments that hold the clavicle to the acromion. If the AC ligaments are torn or stretched, or the coracoclavicular ligaments are involved in a more severe sprain, the joint becomes painful or unstable under this stress. That’s why this test most directly indicates injury to the AC ligament and, in more pronounced cases, the coracoclavicular ligaments, which are the primary stabilizers of horizontal and vertical movement at the AC joint. The subacromial bursa, rotator cuff tendons, and glenoid labrum aren’t the structures this maneuver is designed to assess, so they’re less likely to be implicated by this specific test.