Carotid artery: A key artery located in the front of the neck though which blood from the heart goes to the brain.

There are 2 carotid arteries -- the right and left common carotid arteries -- on each side of the neck. Together, the right and left common carotid arteries provide the principal blood supply to the head and neck.

The left common carotid arises directly from the aorta (the huge artery that comes from the heart). The right common carotid artery arises from the brachiocephalic artery which, in turn, comes off the aorta.

Each of the two common carotid arteries divides to form external and internal carotid arteries. The external carotids are more superficial (closer to the surface) than the internal carotids (which run deep within the neck).

Cholesterol plaques on the inner wall of the carotid artery can lead to strokes.

Picture of Carotid Artery Disease and Plaque Buildup

Carotid comes from the Greek "karotides" which referred to the main arteries going to the head. Interestingly, "karotides" was related to the words "katotikos", stupefying and "karos", deep sleep. The ancient Greeks knew that firm pressure on the carotid arteries produced "deep sleep" by rendering a person unconscious.

"Karotides" also led to the Spanish word "garrote", a term that has entered English, designating both a method of execution by strangulation and the implement (such as a wire, for example, with a handle at each end) used to garrote someone. Garroting caused "deep sleep" (insensibility) and, often, "permanent sleep" (death).