Lastly, we’re looking at the arterial supply to the circle of Willis. Now for detail, that will be
covered in another lecture. But the purpose of your understanding at this point is to remember
that the internal carotid arteries and the vertebral arteries are the vessels that are going to
supply the cerebral circulation. The internal carotids are shown here and here. There are no
branches of the internal carotid arteries until you get into the skull. Then you can start to see
some of the branches here. Again, those will be described in detail in another lecture.
The vertebral arteries are shown here, these major vessels. They come together joined
to form the vessel or artery that we see here. The take home message here is that the
internal carotid arteries contribute to what is known as the anterior circulation to the brain
through their branching pattern that we see around here, whereas the posterior circulation
is supplied by the vertebral arteries. Here is the internal carotid artery labelled for you.
Then here’s the vertebral artery labelled for you as well.