The brain is supplied with blood by four arteries: both carotid arteries at the front and both vertebral arteries at the back.
A – Anatomy of the carotid artery.The common carotid artery arises from the aorta and ascends into the neck. It divides, in the median part of the neck, into two arteries, the internal carotid artery and the external carotid artery.The internal carotid artery supplies blood to the brain.The external carotid artery, through its branches, supplies blood to the neck and the face.The segment of the carotid artery that includes the common carotid artery and the branching out of the internal carotid and the external carotid arteries is called the bifurcation of the common carotid artery (see the drawing).The initial part of the internal carotid artery is bulbous and is called the carotid sinus. This carotid sinus is approximately 2 cm long. This is where the atheromatous plaque responsible for carotid stenoses forms. (See the chapter entitled: “Atheromatous plaque” for additional information.)
B – Anatomy of the vertebral artery.
The vertebral artery arises from the subclavian artery and ascends to the brain, where it joins with the contralateral vertebral artery and forms a single artery: the basilar artery.