What is the Internal Carotid Artery?

Illustration of the human carotid artery
Illustration of the human carotid artery. Getty Images/SEBASTIAN KAULITZKI/Science Photo Library


The carotid (ka-ROT-id) artery is a large blood vessel in the neck that carries oxygen-rich blood away from the heart to the head and brain. There are two carotid arteries located on either side of the neck. They are further divided into internal and external carotid arteries. The function of internal carotid arteries is to supply the brain with oxygen-rich blood. The external carotid arteries function is to supply oxygen-rich blood to the face, neck, and scalp.

If diseased, the carotid artery becomes narrowed or blocked and blood is unable to flow to the brain. The main cause of a stroke is a blockage in the carotid artery.

Causes of Carotid Artery Disease

Carotid artery disease is caused by the buildup of plaque in the arteries that supply blood to the brain. Plaque causes the artery to become stiffened and narrowed, also known as atherosclerosis (ATH-er-o-skler-O-sis). Over time, if the artery becomes blocked, the oxygen and nutrients that are important to structures in the brain are unable to reach the brain and form blood clots – causing a stroke.

Risks of Developing Carotid Artery Disease

Risks of developing carotid artery disease include the following:

The brain survives on a continuous supply of oxygen carried to it in the blood. Brain cells that have been deprived of fresh blood will become damaged, known as ischemia, and brain cells will die, a condition known as infarction.

This results in either a stroke, which is the permanent loss of brain function or a transient ischemic attack, or TIA. A TIA is considered to be a temporary alteration of brain function. However, brain damage is permanent if the lack of blood flow lasts for more than three to six hours. Carotid artery disease is responsible for more than half of all strokes.

Symptoms of Carotid Artery Disease

Carotid artery disease develops over time. Yet, in early stages of the disease, there may be no signs or symptoms. Sometimes it goes unnoticed until a stroke or TIA occurs.

Signs and symptoms of a stroke of TIA may include the following:

  • Numbness or weakness in the face or limbs, often on one side of the body
  • Problems speaking and understanding
  • Tingling around the mouth
  • Inability to see in one or both eyes
  • Sudden dizziness or a loss of balance
  • A headache that occurs suddenly and is severe with no apparent cause

Diagnostic Testing of Carotid Artery Disease

After a thorough medical examination and a test of mental and physical abilities, the following diagnostic tests may be performed:

  • Ultrasound of the carotid artery area n the neck
  • CT Scan
  • MRI scan
  • CT angiography
  • MR angiography (MRA)

Treatment of Carotid Artery Disease

Depending on the amount of blockage – mild to moderate, treatment of carotid artery disease may involve making lifestyle changes such as the following:

  • Quitting smoking
  • Losing weight
  • Eating healthier foods
  • Reducing sodium in the diet
  • Exercising regularly
  • Controlling blood pressure with medication
  • Lowering cholesterol levels with diet and medication
  • Using blood thinners to prevent blood clots

If the blockage is severe and if there is evidence of a stroke or TIA, the option may include surgery such as:

  • Carotid endarterectomy
  • Carotid angioplasty and stenting

Prevention of Carotid Artery Disease

Preventing of carotid artery disease includes adopting the following guidelines:

  • Not smoking
  • Maintaining a healthy weight
  • Limiting cholesterol and fat
  • Eating a variety of fruits and vegetables
  • Limiting the use of sodium
  • Exercising regularly
  • Limiting the use of alcohol
  • Controlling chronic conditions

Patients with risk factors for carotid artery disease should speak with their health care professional to discuss their options.

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