Picture of the Carotid Artery

Human Anatomy

Medically Reviewed by Carol DerSarkissian, MD on June 23, 2021

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The carotid arteries are major blood vessels in the neck that supply blood to the brain, neck, and face. There are two carotid arteries, one on the right and one on the left. In the neck, each carotid artery branches into two divisions:

  • The internal carotid artery supplies blood to the brain.
  • The external carotid artery supplies blood to the face and neck.

Like all arteries, the carotid arteries are made of three layers of tissue:

  • Intima, the smooth innermost layer
  • Media, the muscular middle layer
  • Adventitia, the outer layer

The carotid sinus, or carotid bulb, is a widening of a carotid artery at its main branch point. The carotid sinus contains sensors that help regulate blood pressure. The carotid artery pulse can normally be felt in the neck by pressing the fingertips against the side of the windpipe, or trachea.

Carotid Artery Conditions

  • Carotid artery vasculitis: Inflammation of the carotid artery, due to an autoimmune condition or an infection. 
  • Stroke: A sudden blood clot in the carotid artery can interrupt blood flow to the brain, causing a stroke. Fragments of cholesterol plaque in the carotid artery may also travel into the brain to cause a stroke.
  • Carotid artery stenosis: Narrowing of the carotid artery, usually due to cholesterol plaque buildup, or atherosclerosis. Carotid artery stenosis does not usually cause symptoms until it becomes severe.
  • Carotid artery aneurysm: A weak area of the carotid artery allows part of the artery to bulge out like a balloon with each heartbeat. Aneurysms pose a risk for breaking, which could result in stroke or severe bleeding.
  • Carotid artery embolism: A fragment of cholesterol plaque, or embolus,   may break off from the carotid artery wall and travel to the brain, causing a stroke.
  • Carotid artery atherosclerosis: Cholesterol plaque may slowly build up in the carotid artery wall, over decades. The growing plaque may eventually narrow the carotid artery, known as stenosis, and can lead to a stroke.
  • Amaurosis fugax: Temporary blindness in one eye, usually caused by a fragment of cholesterol plaque, or embolus, breaking off from the wall of the carotid artery. The embolus can get stuck in an artery supplying the eye, blocking blood flow.
  • Temporal arteritis: An autoimmune condition in which branches of the carotid artery become inflamed, known as vasculitis. Fever, a severe headache on one side of the head, and jaw pain when chewing can be symptoms.
  • Carotid hypersensitivity syndrome: In a few people, applying pressure to the carotid sinus can cause fainting from a sudden drop in blood pressure. Symptoms may occur while shaving or wearing a tight shirt collar.

Carotid Artery Tests

  • Carotid artery ultrasound: A probe placed against the skin reflects sound waves off the carotid artery, and a computer constructs images on a screen. Doppler ultrasound can be used to measure blood flow in the carotid artery, including any areas of narrowing, or stenosis.
  • Carotid artery angiography, known as an angiogram: Contrast dye is injected into blood vessels, and X-rays are taken of the neck, revealing images of the carotid arteries. A narrowing, or stenosis, and a bulging, or aneurysm, in the carotid artery may be detected by angiography.
  • Computed tomography angiography (CTA scan): A CT scanner takes multiple X-rays, and a computer compiles them into images of the carotid artery and other arteries of the neck and brain. Contrast dye injected into the blood vessels can help reveal more details of the carotid arteries, such as narrowing or bulging, aiding diagnosis.
  • Magnetic resonance angiography (MRA scan): An MRI scanner uses a high-powered magnet and a computer to create highly detailed images of the carotid artery and other arteries that supply the brain. MRA is superior to CT scanning in detecting strokes and most carotid artery problems.
  • Carotid sinus massage: In a controlled setting, a doctor massages the neck directly over the carotid sinus. This maneuver may unmask carotid sinus problems and can be used to treat certain abnormal heart rhythms.

Carotid Artery Treatments

  • Carotid endarterectomy: A surgery to open a narrowing, or stenosis, caused by cholesterol plaque in the carotid artery. A vascular surgeon cuts open the carotid artery, removes the plaque, and sews the artery closed.
  • Statins: Cholesterol-lowering medicines taken in pill form daily. Statins may reduce the risk of stroke and heart attack in some people with narrowing of the carotid artery, known as stenosis.
  • Aspirin: In people at high risk for heart attack or stroke, a daily aspirin may reduce the risk of a future stroke or heart attack. Aspirin works by interfering with the components of blood that help blood to clot, known as platelets.
  • Clopidogrel (Plavix): Clopidogrel may be used with or without aspirin in people at high risk for stroke or heart attack. Like aspirin, clopidogrel interferes with the components of blood that help blood to clot, known as platelets.
  • Carotid artery stenting: A wire is moved through an artery in the leg up to the carotid artery, and a small wire tube, or stent is expanded inside a narrowing of the carotid artery. Carotid artery stenting can be performed in people with carotid artery stenosis who are poor candidates for endarterectomy.
  • Medications: For temporal arteritis, treatment may consist of corticosteroid medications (steroids), methotrexate or a biologic drug called tocilizumab (Actemra). Tocilizumab is given as an injection under the skin. This medicine may be used along with steroids to lower the amount of steroids that a person needs.