Adson's test is primarily used to screen for which condition?

• A. Carpal tunnel syndrome
• B. De Quervain's tenosynovitis
• C. Thoracic outlet syndrome
• D. Rotator cuff tear

Answer: (C)

Adson's test screens for thoracic outlet syndrome by provoking compression of the structures as they pass through the thoracic outlet. The patient extends the neck and turns the head toward the side being tested while taking a deep breath, and the clinician palpates the radial pulse. A notable decrease or disappearance of the pulse suggests compression of the subclavian artery (and potentially the brachial plexus) in the thoracic outlet, indicating a positive finding for thoracic outlet syndrome. This test targets the space between the clavicle and first rib and the scalene muscles, where vascular or neural elements can be compressed with certain head positions. It is not used to diagnose carpal tunnel syndrome, De Quervain's tenosynovitis, or rotator cuff tears, which involve different structures (wrist/hand median nerve, first dorsal compartment tendons, or the shoulder tendons, respectively).