Carotid Artery

Carotid Artery, the great artery which on each side distributes blood to the different parts of the head, appears to have derived its Greek name carotis from Gr. karos, 'sleep,' there being an old idea that deep sleep was caused by the increased flow of blood through the carotids. Each carotid artery consists of the primitive or common carotid, which, at the upper margin of the larynx or organ of voice, separates into two great divisions, of nearly equal size—the external and the internal carotids. The external carotid supplies the larynx, pharynx, tongue, face, and scalp with blood; its principal branches being the superior thyroid, the lingual, the facial, the occipital, the posterior auricular, the internal maxillary, and the temporal. The internal carotid enters the cavity of the cranium through a somewhat tortuous canal in the temporal bone, and after perforating the dura-mater, or fibrous membrane of the brain, separates into the anterior and middle cerebral arteries, which are the principal arteries of the brain; while in its course through the dura-mater, it gives off the ophthalmic artery. See AORTA, CIRCULATION.