The Adson test assesses thoracic outlet syndrome due to compression of which artery?

• A. Brachial artery compression
• B. Axillary artery compression
• C. Subclavian artery compression
• D. Vertebral artery compression

Answer: (C)

Adson’s test targets compression of the subclavian artery as it passes through the thoracic outlet, usually where the anterior scalene muscle overlaps the first rib. When the head is extended and turned toward the tested side and the patient inhales deeply, the space between the clavicle/first rib and the scalene muscles narrows. A diminished radial pulse during this maneuver indicates arterial compression of the subclavian artery, which is why this test is used for thoracic outlet syndrome. The vertebral artery isn’t the vessel affected by this test, and the axillary or brachial arteries are downstream vessels not primarily evaluated by Adson’s maneuver.