Blood Supply to the Brain

This is Dr. Cal Shipley with a review of the blood supply to the brain.

Anterior and Posterior Blood Supply

Blood is supplied to the brain by two pairs of arteries. The anterior supply supplies blood primarily to the middle and front portions of the brain and consists of the left and right carotid arteries. The posterior supply supplies blood primarily to the brain stem and back portions of the brain and consists of the right and left vertebral arteries, which then join together to form the single basilar artery.

Rotating the brain so that we have a view from the left side. We can now more clearly see how the anterior supply originating from the carotid arteries distributes blood primarily to the middle and front portions of the brain. Two of the major arteries in the anterior circulation are the anterior and middle cerebral arteries. The posterior supply originating from the basilar artery supplies mostly the brain stem and the rear portions of the brain. The posterior cerebral artery is a major vessel in the posterior circulation.

The Circle Of Willis

In a prime example of nature’s wonderful design, there is a communicating artery which joins the two systems known as the posterior communicating artery. This vessel is part of the circle of Willis. In the event that there is sudden impairment of blood flow to the brain from either the anterior or posterior system, the communicating arteries allow for crossover flow which may help to prevent damage to the portion of the brain affected by the impaired flow.

Cal Shipley, M.D. copyright 2020