THE EXTERNAL CAROTID) (arteria carotis externa, supoficialis vel anterior, Scemm. fa ciale of Chaussier,) extends from the bifurca tion of the primitive carotid to the neck of the condyle of the lower jaw, where it terminates by dividing into the superficial temporal and internal maxillary arteries. In this course it describes a curve, the concavity of which is outwards and a little backwards, as it ascends between the ear and the ramus of the lower jaw. At first it is superficial, merely covered by the integuments, platysma and cervical fascia; it then ascends under the ninth or hypoglossal nerve and the posterior belly of the digastric and stylo-hyoid muscles, and buries itself in the substance of the parotid gland. In ternally it rests at first on the commencement of the internal carotid, then over the middle con strictor of the pharynx, the stylo-pharyngeus and stylo-glossus muscles, the glosso-pharyn geal nerve and the styloid process of the tem poral bone ; the superior and inferior pharyn geal nerves coming from the par vagum also pass under it in their course to the pharyngeal plexus. The part of the parotid gland which the external carotid first enters is the internal surface of its lower extremity, consequently the whole thickness of the gland covers it at that part; but in pas,sing through the gland the artery becomes more superficial as it ascends and is covered only by a very thin layer of the glandular substance at the place where it ter minates. The branches of the portio dura
forming the pes anserinus cross the course of the carotid in the substance of the gland, being superficial to it and separated from it by the posterior facial vein and part of the glandular substance.
Branches qf the external carotid.*—The ex ternal carotid gives off eight principal branches; three anteriorly, the superior thyroid, the lin gual, and the labial or facial ; two posteriorly, the occipital andposterior aural ; one internally, the ascending pharyngeal ; and two superiorly, the superficial temporal and internal maxillary, besides several smaller branches, the number and origins of which are subject to great irregularity, and which are distributed to the stemo-mastoid muscle, the superior cervical ganglion of the sympathetic nerve, the digastric, stylo-hyoid, stylo-pharyngeus, and stylo-glos sus muscles, &c., to the parotid gland, the external ear, and to the integuments.