Adson's sign

Adson’s sign or Adson’s maneuver is used to diagnose thoracic outlet syndrome. The clinician has the patient extend their neck and turn their head to the side that is being tested. The patient then holds their breath and the radial pulse is palpated. If the pulse decreases, then vascular compromise is present suggesting thoracic outlet syndrome. Alternatively, auscultation of the subclavian artery can be done. The Adson’s maneuver would cause a subclavian artery bruit to be heard if positive.

Thoracic outlet syndrome occurs when there is nerve compression at the superior thoracic outlet caused by pressure on a neurovascular bundle that passes between the anterior scalene and middle scalene muscles. There is some degree of variability regarding the number of nerves involved that innervate the upper limb. Arterial circulation can also be compromised in a similar fashion, specifically the subclavian artery and rarely the subclavian vein, which does not normally pass through the scalene hiatus.