Which test specifically evaluates stability of the acromioclavicular joint?

• A. AC Compression Test
• B. Apprehension Test
• C. Cross-Body Adduction
• D. Relocation Test

Answer: (C)

Stability of the acromioclavicular joint is tested by provoking stresses that directly affect the joint ligaments. The Cross-Body Adduction maneuver moves the arm horizontally across the chest, which converts the scapula and clavicle into a relative horizontal shear and compression across the AC joint. If the AC ligaments (and the supporting structures around the joint) are injured or lax, this stress reproduces pain and can reveal instability at the AC joint. This makes it a focused test for AC joint pathology and stability.

In contrast, the Apprehension and Relocation tests are aimed at the glenohumeral joint’s anterior stability, not the AC joint. The AC Compression Test also targets the AC joint but uses a different mechanism (directly compressing the distal clavicle toward the acromion). So the Cross-Body Adduction maneuver best assesses AC joint stability.