CAROTID ARTERY. The great artery which on each side distributes blood to the different parts-of the head, appears to have derived its name either from Gr. kara, the head, or, more probably, from Gr. kora% sleep, there being an old idea, which the researches of Dr. Alexander Fleming have shown to be correct, that there was some connection between deep sleep and compression of these vessels.
Each C. A. 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 carotid. The external carotid supplies the larynx, tongue, face, and scalp with blood; its principal branches being the superior thyroid, the lingual, the facial, the occipital, the posterior aural, the internal maxillary, and the temporal. The last-named artery is occasionally opened by the surgeon in preference to a vein, as, for example, in certain cases of cerebral apoplexy. The internal carotid enters the cavity of the cranium through a somewhat tortuous canal in the temporal bone, and after per forating 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, which subdivides into several small branches that supply the eye and surrounding parts. See CIRCULA TION. Surgery.—Wounds of the carotid trunks are generally from stabs. Suicides have a vague desire to cut them, but rarely cut sufficiently deep by the side of the windpipe. Of course, should either vessel be wounded, death results almost immediately. Punc
tured wounds, however, may not be immediately fatal; they may heal, or a false aneu rism (q.v.) may result. Such an occurrence happened about twenty years ago in Scotland. A young man was stabbed close to the root of the neck; a pulsating tumor formed, which rapidly increased, and would undoubtedly have burst before lono. had not prof. Symc of Edinburgh cut into it, and, by an operation requiring extraordinary courage and dexterity, tied the common C. A. above and below the part stabbed; thereby saving not only the life of the patient, but that of the man who had inflicted the wound, and who was then in prison awaiting his trial.
Sir Astley Cooper was the first to tie the common carotid for spontaneous aneurism, in Nov., 1805; and since then, the operation has been successfully performed in a num loer of cases. Owing to the numerous interchange of branches between vessels of both sides of the head, cutting off the supply of blood through one carotid is seldom followed by affections of the brain. Such have, however, occurred in a few instances; but Dr. Mussey of America tied both carotids within twelve days of each other without any such result.
The common carotid in the horse is the termination of the right arteria innominata. It is a large vessel, about an inch which emerges from the chest below the wind pipe, and divides into the right and left carotids. These bend upward, having the wind pipe between them, gradually inclining inwards at the upper part, where each divides into external and internal carotid, and a large anastomosing branch arising from beween these two.