Which test assesses AC joint stress by compressing the acromioclavicular joint with interlaced fingers?

• A. AC shear test
• B. Cross body adduction
• C. Yergason's test
• D. Adson's test

Answer: (A)

Assessing AC joint pathology by applying a compression across the acromioclavicular joint. The AC shear test uses interlaced fingers placed behind the shoulder to squeeze the clavicle and acromion together, creating a shearing force that stresses the AC joint. If there’s sprain, separation, or inflammation, this maneuver commonly reproduces pain and may reveal joint instability.

This differs from the cross-body adduction maneuver, which stresses the AC joint by bringing the arm across the chest to load the joint, producing pain through a different loading pattern. Yergason's test targets the biceps tendon in the bicipital groove, not the AC joint, while Adson's test screens for thoracic outlet issues affecting vascular and neural structures rather than the AC joint itself.