Stroke

A stroke is defined as a sudden loss of brain function due to a blocked or burst blood vessel. There are two classifications of stroke, ischemic and hemorrhagic. Ischemic strokes account for approximately 80 percent of all strokes and result from blockage of the blood supply to the brain. Hemorrhagic strokes account for the remaining 20 percent of all strokes and result from bleeding in the brain. When the bleeding is in the brain itself, it is an intracerebral hemorrhage; if the bleeding occurs between the brain and the skull, it is a subarachnoid hemorrhage.

The brain needs a continuous and fresh supply of oxygen and glucose to function. Oxygen and glucose are carried in the blood and reach the brain through four arteries arranged in two systems. The carotid arteries in the neck carry most of the blood to the brain. The vertebral arteries in the spine join at the base of the brain to form the basilar artery. They supply blood to the core of the brain, which deals with vital functions. Any interruption of blood supply to the brain interferes with the brain’s ability to function.