Stroke Blood Flow

Oxygen is essential for brain function: 25 percent of the body’s oxygen is used by the brain, yet the brain represents only one fortieth of the body’s weight. Arteries transport oxygen rich blood to the brain. A lack of blood and oxygen to any part of the brain can result in a stroke. The supply of freshly oxygenated blood from the heart to the brain is delivered via the carotid and basilar arteries.

Carotid Arteries

The carotid arteries run up both sides of the neck, and supply oxygen to the “carotid territory” of the brain. The carotid territory includes the frontal and temporal lobes. Strokes in the carotid territory, the “front” of the brain, are referred to as anterior strokes. Anterior strokes produce the most common stroke symptoms. Anterior strokes can be caused by blood clots or narrowing in the carotid arteries as well as in smaller arteries within the brain. Speech difficulties, vision problems, tingling, and paralysis may result from an anterior stroke.

Basilar Arteries

Blood CirculationThe basilar arteries are part of the vertebrobasilar circulation system, located at the base of the skull. The two vertebral arteries connect to form a single basilar artery that provides the “vertebrobasilar territory” of the brain with oxygen. This territory includes the brain stem, cerebellum, and occipital lobes. A stoke in this region of the brain is referred to as a posterior stroke (meaning the stroke affects the back of the brain). Posterior strokes cause some of the less common stroke symptoms.

Strokes in the basilar territory can sometimes affect both sides of the body. Posterior strokes may also cause headaches, visual disturbances, speech problems, nausea, difficulty swallowing, and weakness in the legs or arms.

Hypertension and Arteries

Hypertension (high blood pressure) damages artery walls. The walls become fragile and “brittle.” If artery walls in the brain rupture, a hemorrhagic stroke may occur. Controlling hypertension is an essential part of stroke prevention and treatment.

Resources

Beers, M. H.