Carotid arteries
The carotid arteries are vital blood vessels that supply oxygen-rich blood to the brain. They branch from the common carotid arteries, which arise from different sources: the left common carotid artery comes directly from the aortic arch, while the right one originates from the brachiocephalic artery. The internal carotid arteries are crucial for brain perfusion, and slight dilations known as carotid sinuses play a role in regulating blood pressure. The external carotid arteries serve the face, neck, and structures such as the thyroid and tongue.
When these arteries become obstructed due to plaque buildup—often influenced by lifestyle factors—carotid artery disease can develop, leading to serious conditions like stroke. Symptoms of a stroke can include weakness, impaired speech, sensory loss, and confusion. The impact of a stroke varies based on the affected arteries and can lead to significant long-term effects on motor and cognitive functions. Awareness of the carotid arteries and their health is essential for understanding strokes and their prevention.
Subject Terms
Carotid arteries
Also known as: Carotid pulse
Anatomy or system affected: Blood vessels, brain, circulatory system, heart, neck
Definition: The two major arteries supplying blood to the head and neck. Each divides into an external common carotid and an internal common carotid branch
Structure and Functions
The internal and external carotid arteries branch from the common carotid arteries at about the level of the thyroid cartilage. The left common carotid artery stems directly from the aortic arch, but the right common carotid artery is derived from the brachiocephalic artery. The external carotid arteries supply blood to the face, thyroid, tongue, and pharynx. A branch from the external carotid arteries, the middle meningeal artery, supplies the deep structures of the face and sends a large branch to the dura mater in the brain. A slight dilation in the internal carotid arteries just past the bifurcation is called the carotid sinus. Specialized nerve endings within the carotid sinuses respond to changes in arterial blood pressure to maintain blood supply to the brain and body. The anterior cerebral arteries provide blood supply to structures such as the frontal and parietal lobes of the brain. An occlusion (obstruction) in the main trunk of an anterior cerebral artery results in contralateral hemiplegia (paralysis) that is greater in the leg than in the arm. Bilateral paralysis and sensory impairment result when there is total occlusion of both anterior cerebral arteries. The middle cerebral arteries supply arterial blood to portions of the temporal, parietal, and frontal lobes of the cerebral cortex. Occlusion of the middle cerebral artery results in severe aphasia (loss of speech) when the language hemisphere is involved, loss of position sense and touch discrimination, and severe hemiplegia in the upper extremities and the face.
Disorders and Diseases
The carotid arteries are responsible for supplying blood and oxygen to the brain. When plaque builds up in these arteries over time and due to lifestyle choices, this blood supply may be blocked, leading to carotid artery disease and stroke. Major clinical features associated with arterial insufficiency in the brain may cause a cerebral vascular accident or stroke. Strokes are associated with signs and symptoms such as weakness in one to four extremities; increased tendon reflexes; ataxia; bilateral Babinski sign; dysphagia; dysarthria; syncope, stupor, coma, dizziness, or memory disturbances; visual disturbances (diplopia, nystagmus, ptosis, paralysis of single eye movements); numbness of the face; confusion; dementia; coma; hemiparesis; visual aphasia or word blindness; occasional blindness; disturbance of all functions involving speech and communication; and dysphasia.
A thorough history and physical examination should be done on all patients with cerebrovascular disease. An inadequate history is probably the most frequent cause of diagnostic error. Often neither the patient nor the family can recall when initial symptoms started. Two significant phenomena that are characteristic of all varieties of stroke are the suddenness of occurrence and the findings of some degree of improvement following stabilization. Hemiplegia is the classic sign of stroke and is found in lesions involving the cerebral hemispheres or brain stem.
Bibliography
A.D.A.M. Medical Encyclopedia. "Carotid Artery Disease." MedlinePlus, July 31, 2011.
A.D.A.M. Medical Encyclopedia. "Carotid Artery Surgery." MedlinePlus, June 4, 2012.
Guyton, Arthur C., and John C. Hall. Guyton and Hall Textbook of Medical Physiology. 12th ed. Philadelphia: Elsevier/Saunders, 2011.
Moore, Keith L. Clinically Oriented Anatomy. Philadelphia: Lippincott Williams & Wilkins, 2009.
National Heart, Lung, and Blood Institute. "What Is Carotid Artery Disease?" National Institutes of Health, November 1, 2010.
Naylor, A. Ross. Carotid Artery Surgery: A Problem-Based Approach. New York: Elsevier Health Sciences, 2000.
Rohen, Johannes W. Color Atlas of Anatomy: A Photographic Study of the Human Body. Philadelphia: Lippincott Williams & Wilkins, 2006.
Rosenberg, Norman. Handbook of Carotid Artery Surgery. New York: Taylor & Francis, 1994.
“What Are The Carotid Arteries?” Cleveland Clinic, 11 Oct. 2022, my.clevelandclinic.org/health/articles/21492-carotid-artery. Accessed 23 July 2023.