Subclavian Steal Syndrome typically presents with symptoms triggered by exercising which limb due to retrograde vertebral artery flow?

• A. Left leg exercise
• B. Left arm exercise
• C. Head turning
• D. Chest wall exercise

Answer: (B)

Subclavian Steal happens when there is significant stenosis near the origin of the subclavian artery, before the vertebral artery joins the basilar system. That blockage creates a pressure gradient so blood can flow backward down the vertebral artery to supply the arm. When the affected arm is exercised, its increased demand pulls blood away from the brain’s posterior circulation, causing vertebrobasilar symptoms such as dizziness, vertigo, or even syncope. This is why the trigger is exercising the limb on the side of the stenosis—most often the left arm, given the left subclavian’s direct connection to the aorta. The other activities listed wouldn’t generate the same retrograde flow, so they don’t produce the characteristic symptoms.