carotids

The carotids are the major arteries in the neck that supply the head and brain. Each side has a common carotid artery that ascends within the carotid sheath. Around the level of the upper border of the thyroid cartilage, the common carotid divides into the internal carotid artery, which continues to the skull, and the external carotid artery, which supplies the face and neck.

The internal carotid artery enters the skull and contributes to the cerebral circulation, including branches that participate in the Circle of Willis; it supplies the anterior and middle parts of the brain. The external carotid artery gives off several branches in the neck and face, such as the superior thyroid, lingual, facial, occipital, posterior auricular, maxillary, and superficial temporal arteries, which supply the neck, face, and scalp.

The carotid sinuses and bodies are specialized sensors located near the bifurcation. The carotid sinus contains baroreceptors that regulate blood pressure, while the carotid body contains chemoreceptors that respond to changes in blood oxygen and carbon dioxide levels.

In clinical practice, carotid disease is most often due to atherosclerotic stenosis of the common or internal carotid arteries and can lead to transient ischemic attack or stroke. Evaluation commonly uses duplex ultrasonography, CT or MR angiography. Treatments include medical management and, in selected cases, carotid endarterectomy or carotid artery stenting.