CT Circle of Willis (Overview) - Video Lesson

Hey everybody, welcome back. This lesson is an overview of the circle of Willis as seen in CT imaging. We'll start with an illustration. This is an illustration of the circle of Willis. The circle of Willis is a vascular structure inside of the brain that directs oxygenated blood into the brain. It's called a circle because the vessels are all interconnected into the shape of a circle. In this illustration, the circle of Willis is displayed flat on a single plane. In reality, the circle of Willis is not actually flat. This is a good way of learning the general position of the vessels. Oxygenated blood is supplied into the circle of Willis by three arteries. Posteriorly, the circle of Willis is supplied by the basilar artery. The basilar artery itself is formed by the union of the vertebral arteries at about the level of the foramen magnum. In this illustration, the left vertebral artery is labeled, but there's an identical right vertebral artery on the other side of the illustration. The anterior side of