Carotid artery
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The carotid artery is a major artery of the head and neck. There are two carotid arteries, one on the left and one on the right. Their accessibility and proximity to the surface makes them useful for checking the pulse.
From their origins and for about half their length, the carotid arteries are known as common carotid arteries. The left carotid arises from the arch of the 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. The carotids then continue along similar paths within their respective sides of the neck and skull.
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 latter two could be considered a terminal bifurcation of the artery; the maxillary artery is the larger of the two.
The internal carotid artery has no branches in the neck. It ascends and enters the skull through the carotid canal. Inside the cranium, it gives off the ophthalmic artery and trifurcates into the anterior cerebral artery, middle cerebral artery, and posterior communicating artery. The latter three arteries contribute to an important anastomosis supplying the brain, the Circle of Willis.
See also blood pressure.