Carotid artery: Either of the two key arteries located in the front of the neck, through which blood from the heart goes to the brain. The right and left common carotid arteries are located on each side of the neck. Together, these arteries provide the principal blood supply to the head and neck. The left common carotid artery arises directly from the aorta. The right common carotid artery arises from the brachiocephalic artery, which, in turn, comes off the aorta. Each of the two divides to form external and internal carotid arteries. Cholesterol plaque on the inner wall of the carotid artery can lead to a stroke.