O'Brien's Test is suggestive of either SLAP lesion or AC joint pathology.

• A. Subacromial impingement
• B. SLAP lesion or AC joint pathology
• C. Rotator cuff tear
• D. Biceps tendonitis

Answer: (B)

O'Brien's test is used to screen for intra-articular shoulder pathology involving the superior labrum and the AC joint. To perform it, position the arm in 90 degrees of forward flexion with a slight adduction and the forearm in internal rotation (thumb pointing down), then have the patient resist a downward force. A positive result is when pain or a painful click occurs in this position.

If the pain is reproduced and then decreased or absent when the forearm is supinated (or externally rotated), this pattern points toward a SLAP lesion. If pain remains localized to or is worsened at the AC joint, the finding suggests AC joint pathology. The test is not specific for subacromial impingement, rotator cuff tear, or biceps tendonitis, which are better evaluated with other provocative tests.