Overview
Introduction
A high‑grade plaque or occlusion just before the vertebral artery origin turns the subclavian artery into a low‑pressure conduit.
A high‑grade plaque or occlusion just before the vertebral artery origin turns the subclavian artery into a low‑pressure conduit. When the arm works, its metabolic demand pulls blood down the vertebral artery, stealing flow that should nourish the brainstem, cerebellum, and occipital cortices. The resulting vertebrobasilar hypoperfusion produces dizziness, visual fog, or ataxia that appear only with ipsilateral arm activity. Because the problem is vascular, the nurse’s first clues are a measurable blood‑pressure gap and a change in pulse character—findings that can be obtained at the bedside before any imaging is ordered.