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Carotid artery

The carotid artery is a major artery of the head and neck that supplies blood to the head and neck. There is a left and right carotid artery.

When they first arise, the carotid arteries are known as common carotid arteries. The left carotid arises from the arch of aorta, while the right carotid arises as one of the branches of the bifurcation of the brachiocephalic artery (trunk) into the carotid and right subclavian artery. They then normally continue along similar paths.

At approximately the level of the third cervical vertebra, the common carotid branches into the internal and external carotid arteries.

The external carotid artery usually has eight branches in the neck: superior thyroid artery, lingual artery, facial artery, ascending pharyngeal artery, occipital artery, posterior auricular artery, maxillary artery, and superficial temporal artery.

The internal carotid artery has no branches in the neck. It ascends and enters the cranium through the carotid canal. Inside the cranium, it gives off the opthalmic artery and trifurcates into the anterior cerebral artery, middle cerebral artery, and posterior communicating artery. The latter three arteries contribute to an important anastomosis in the brain, the Circle of Willis.