The carotid arteries are the main arteries that supply blood to the brain, neck, and face. There are two of them — the left and right common carotid arteries. Each one runs up the side of the neck. The right common carotid originates from the brachiocephalic artery, while the left comes directly off the aortic arch. As they ascend the neck, each common carotid artery divides into an internal and an external branch. The internal carotid artery travels deeper into the skull to supply the brain, wh