What is the Common Carotid Artery?

The common carotid artery is a blood vessel that delivers blood from the heart to the head and neck. A major branch of the aorta, it is a paired vessel, with the left common carotid artery supplying the left side of the neck and head and the right common carotid artery supplying the right side. Each subsequently splits to form the internal and external carotid arteries, with the internal carotid bringing blood to the brain and the external carotid bringing blood to various areas of the head and neck, including the face, larynx, and skull. The function of this vessel is to transport oxygenated blood, rich in energy-supplying nutrients like glucose, to these parts of the body.

Originating in the thoracic or chest region, the common carotid artery arises from the arch of the aorta. The aorta is the largest artery exiting the heart, ascending a few inches in the thorax, curving to the left, and then changing its course to descend past the heart and deliver blood to the rest of the body. The arch is found where it switches direction.

Arising directly from the aortic arch in the thorax is the left common carotid, which ascends the neck. The right common carotid does not exit the aorta directly but rather is a branch of the brachiocephalic artery, which splits off the aortic arch just to the right of the left common carotid. It is not until the brachiocephalic artery reaches the right sternoclavicular joint in the base of the neck, where the right collarbone meets the right side of the sternum, that the right common carotid artery arises.

The two branches of the common carotid artery then climb either side of the anterior neck, each roughly in line with the angle of the jawbone. Upon reaching the top of the thyroid cartilage, better known as the Adam’s apple, the left and right common carotid divide into their respective internal and external carotid arteries. The internal carotid is the larger of the two, as it has the significant task of bringing nutrient-filled blood to the brain. Without the glucose this vessel transports, the brain would not receive the fuel it requires to continue functioning.

Though the external carotid artery supplies a greater number of structures, it is much smaller than the internal carotid. The common carotid artery forms this branch at the level of C4, the fourth cervical vertebra in the neck. While the internal carotid continues straight upward past the angle of the jaw, the external carotid courses slightly forward as it ascends, quickly branching into several smaller vessels like the superior thyroid, lingual, which supplies the tongue, and facial arteries.