The Circle of Willis is a ring or circle of arteries located at the base of the brain. It is also known by several other names, most commonly the cerebral arterial circle and arterial Circle of Willis. This part of the brain was first discovered by the English doctor Thomas Willis in the 17th century. The circle is important to itself and the brain, because the way the arteries are laid out provides a form of backup in case any of them is obstructed. If one artery is constricted or blocked, the flow of blood from the other arteries in the circle will most often be enough to preserve the necessary flow to the brain and prevent damage.
Once the Circle of Willis was discovered, years of research were conducted into its purpose and functions. It has been determined that the circle provides the necessary blood and fuel for all thought processes and even physical processes in the brain. This very efficient cluster of arteries essentially provides all of the blood that comes and goes from the brain, which it needs to survive and operate.