What would a positive Adson's test suggest?

• A. Intrinsic Shoulder Stability
• B. Compression of the Brachial Plexus
• C. Rotator Cuff Tear
• D. Cervical Radiculopathy

Answer: (B)

A positive Adson's test suggests compression of the brachial plexus, which is an important finding in the assessment of thoracic outlet syndrome. During the Adson's test, the patient's arm is positioned, and the clinician palpates the radial pulse. The patient is then instructed to take a deep breath and turn their head towards the tested side. If the pulse diminishes or becomes absent, it indicates that the structures in the thoracic outlet, which include the brachial plexus and subclavian artery, may be compressed due to tightness or structural abnormalities in nearby tissues, such as scalene muscles or cervical ribs.

The Adson's test specifically evaluates the relationship between the positional changes of the head and neck and the vascular and neurogenic structures that pass through the thoracic outlet. A positive sign is indicative of neurovascular compromise, which can manifest as pain, numbness, or weakness in the upper extremity. The presence of these symptoms along with a positive test signifies that the brachial plexus is being compromised, confirming the diagnosis of thoracic outlet syndrome rather than conditions like intrinsic shoulder stability, rotator cuff tears, or cervical radiculopathy.