What are the carotid arteries?
- Left common carotid artery.
- Right common carotid artery.
Your common carotid arteries travel from your upper chest to your skull. Along the way, each one divides (or “bifurcates”) into two branches:
- Internal carotid artery.
- External carotid artery.
Your internal and external carotid arteries give rise to many smaller artery branches that carry blood throughout your head and neck, nourishing your organs and tissues.
What is the function of the carotid arteries?
Your carotid arteries are an important part of your circulatory system. They send oxygen-rich blood to organs and tissues in your head and neck, including your brain.
Ideally, this is a smooth journey. But a blockage or blood clot in one of your carotid arteries can interfere with this process and cause serious complications.
Where are the carotid arteries located?
Your carotid arteries are located primarily in your neck. They begin in your upper chest, just below your neck, and travel upward toward your skull. The chart below shows anatomical landmarks where each specific carotid artery begins and ends.
|Left common carotid artery.||Branches from your aortic arch.||Divides into your left internal and left external carotid arteries at the left carotid bifurcation.|
|Right common carotid artery.||Branches from your brachiocephalic artery.||Divides into your right internal and right external carotid arteries at the right carotid bifurcation.|
|Internal carotid arteries (left and right).||Begin at the carotid bifurcation on either side of your neck.||Divide into your anterior cerebral artery and middle cerebral artery. These are part of a major junction of blood vessels at the bottom of your brain called the circle of Willis.|
|External carotid arteries (left and right).||Begin at the carotid bifurcation on either side of your neck.||Divide into your internal maxillary artery and superficial temporal artery on either side of your neck, up near your ear.|
What is the anatomy of the external carotid artery?
Your external carotid arteries begin at the carotid bifurcation on either side of your neck. Each external carotid artery travels upward along the side of your neck toward your ear. Near your ear, it divides into its two terminal branches: your maxillary artery and superficial temporal artery.
Branches of the external carotid artery
Your external carotid arteries each give rise to eight branches, which supply blood to many structures in your neck and face. These branches include your:
- Superior thyroid artery.
- Ascending pharyngeal artery.
- Lingual artery.
- Facial artery.
- Occipital artery.
- Posterior auricular artery.
- Maxillary artery.
- Superficial temporal artery.
What is the anatomy of the internal carotid artery?
Your internal carotid arteries begin at the carotid bifurcation on either side of your neck. Each artery travels up through your neck until it reaches the base of your skull. Researchers call this part of the internal carotid artery the C1 or cervical segment. “Cervical” means something related to your neck.
Each internal carotid artery then goes through an opening in your skull known as the carotid canal. This is an anatomical landmark that divides the extracranial and intracranial parts of your artery. Extracranial means outside your skull, and intracranial means inside your skull. Once inside your skull, your internal carotid artery follows a twisting, winding path. Healthcare providers divide the intracranial part into six segments:
- C2: Petrous segment.
- C3: Lacerum segment.
- C4: Cavernous segment.
- C5: Clinoid segment.
- C6: Ophthalmic segment.
- C7: Communicating segment.
Some providers use other classification systems to describe these segments. For example, an older system divides your internal carotid artery into four parts:
- C1: Cervical part.
- C2: Petrous part.
- C3: Cavernous part.
- C4: Cerebral part.
Many people never need to know the names of these segments. But this information can be helpful if you have a condition like an aneurysm that affects your carotid arteries. Your healthcare provider may use these terms to describe the aneurysm’s location. An aneurysm is an abnormal dilation, or ballooning, of your blood vessel. It can form if the wall of the blood vessel is weakened by infection, damage or inflammation.
Branches of the internal carotid artery
Your internal carotid arteries each give rise to several branches inside your skull. These arteries supply blood to your brain and eyes.
Branches of your internal carotid arteries include your:
- Ophthalmic artery.
- Posterior communicating artery.
- Anterior cerebral artery.
- Middle cerebral artery.
Conditions and Disorders
What conditions and disorders affect the carotid arteries?
Problems that can affect your carotid arteries include:
- Carotid artery disease: This condition is also called carotid artery stenosis. Stenosis means “narrowing.” Narrowed carotid arteries usually occur due to atherosclerosis. This is an accumulation of plaque along your artery walls. In your carotid arteries, this plaque often forms near the carotid bifurcation. Plaque buildup raises your risk of a transient ischemic attack (TIA) or a stroke. That’s because blood clots can form on the plaque and ultimately break off, traveling to an artery in your brain and blocking blood flow. The plaque itself can also rupture, and a piece can break off and travel to your brain.
- Carotid artery aneurysm: If the wall of your carotid artery is weak, an aneurysm can form. This is a bulge in your artery that may get bigger over time. Blood clots can form in the aneurysm and interfere with blood flow to your brain. If the aneurysm grows large enough, it can burst (rupture).
- Carotid artery dissection: This is a tear in the lining of your carotid artery that can slow or stop blood flow to your brain. It can lead to serious complications like a stroke.
- Fibromuscular dysplasia (FMD): This is a disorder that affects how the layers of your blood vessels develop. It can lead to narrowing of your carotid arteries, aneurysms or dissections.
For most people, carotid artery conditions cause no symptoms until there’s a medical emergency like a TIA or stroke.
Call 911 or your local emergency number if you experience:
- Drooping or paralysis of one side of your face.
- Slurred speech or difficulty forming words.
- Sudden loss of vision in one or both eyes. You may notice a dark shade coming down over your field of vision.
- Weakness or loss of muscle strength in one or both sides of your body.
- Loss of feeling in one or both sides of your body.
Depending on your symptoms, you may not be able to call for help. Educate your loved ones about these symptoms so they know when to seek help for you.
Common tests to check your carotid arteries
To check your carotid arteries, your provider may use a stethoscope to hear blood flow through your neck. They listen for a whooshing sound called a carotid bruit, which may indicate the presence of turbulent blood flow. Such blood flow can be a hint that there may be some plaque formation.
If you have a bruit, or your provider has other reasons to suspect problems, you may need imaging tests such as:
- Carotid ultrasound.
- Computed tomography (CT) scan.
- Carotid angiogram.
- Magnetic resonance angiogram (MRA).
Medications and surgical procedures can treat narrowed or blocked carotid arteries. If you have a carotid artery blockage, your healthcare provider may recommend medications such as:
Procedures you may need include:
How can I keep my carotid arteries healthy?
To keep your carotid arteries healthy, you may need to reduce your cholesterol levels. Your provider may prescribe medication to help.
You can also make lifestyle changes to support your blood vessels and heart, including:
- Avoid smoking, vaping and all tobacco products. Ask your provider for resources to help you quit.
- Eat a heart-healthy diet like the Mediterranean diet.
- Exercise for at least 30 minutes per day. But be sure to ask your provider before starting any new exercise plan.
- Keep a weight that’s healthy for you.
What questions should I ask my doctor?
You may want to ask your healthcare provider:
- Do I have any risk factors for carotid artery disease?
- What lifestyle changes can I make to help keep my carotid arteries healthy?
- Do I need imaging tests to check the condition of my carotid arteries?
- If I have blockages in my carotid arteries, what treatments should I consider?
A note from Cleveland Clinic
Your carotid arteries are a vital part of your circulatory system. They have the important job of sending oxygen-rich blood to your brain and other parts of your head and neck. If you have concerns about the health of your carotid arteries, talk to your healthcare provider. They can share information on lifestyle changes to help keep all of your blood vessels working at their best.
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