A stroke involves brain damage caused by a loss of blood circulation to an area of the brain. The blockage usually occurs when a clot or (less often) piece of atherosclerotic plaque breaks away from an artery elsewhere in the body and lodges within the vasculature of the brain.
Last reviewed 12/26/2011 by Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Senior Physician, Massachusetts General Hospital.
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