Mayo Clinic Neurology Board Review

"The cerebrospinal vasculature originates at the aortic arch. The right brachiocephalic artery divides into the right common carotid artery and the right subclavian artery. The left common carotid and left subclavian arteries arise directly from the aortic arch. The 2 common carotid arteries bifurcate into the internal and external carotid arteries. The anterior circulation of the brain includes the distal branches from the internal carotid artery, including the anterior cerebral artery and the middle cerebral artery. The vertebral arteries arise from the subclavians and join at the pontomedullary junction, forming the basilar artery. The vertebrobasilar system and distal branches are commonly known as the posterior circulation of the brain"--