Which maneuver directly assesses AC joint involvement?

• A. Yergason's test
• B. Neer test
• C. Cross-body adduction test
• D. O'Brien's test

Answer: (C)

Cross-body adduction directly loads the acromioclavicular (AC) joint by bringing the arm across the chest, which pinches and stresses the AC joint. If there is pathology there—such as AC joint arthritis, sprain, or AC separation—this maneuver typically reproduces pain at the top of the shoulder. The other tests target different structures: Yergason’s test assesses the biceps tendon and transverse ligament; Neer’s test stresses the subacromial space and impingement; O’Brien’s test is used for labral (SLAP) lesions with secondary AC involvement being less specific. Because the cross-body adduction maneuver specifically provokes the AC joint, it is the best choice for directly assessing AC joint involvement.