After the origin of the superior labial the facial artery is reduced to a very small size, and its continuation is by some called the external nasal, arteria nasalis externa com munis. It continues to pass obliquely up wards, forwards, and inwards under the levator labii superioris, to which it. gives branches : after anastomosing with the infra-orbital artery and giving off branches, which pass forward on the lateral surface of the nose, namely, e, laterales nasi, andf, dorsales nasi, which freely anastomose with each other, with the artery of the septum, and those of the opposite side on the dorsum of the nose, it emerges from between the two heads of the levator labii superioris, and becoming subcutaneous, ter minates at the inner canthus of the eye by anastomosing with the termination of the nasal branch of the ophthalmic, at which place it has received the name of the angular artery.
Irregularities of the labial or facial artery. It sometimes happens that the facial artery is smaller than usual, and terminates at the angle of the mouth or even below the situation of the usual origin of the inferior coronary; in this case the transverse facial branch of the tempoml genemlly fnrnishes the branches which the coronary has failed to produce ; on the other hand the labial artery is sometimes of a larger size than usual, as happens when it furnishes supernumerary branches, such as the ranine or sublingual. The facial artery is the principal source of communication between the superficial and deep branches of the external carotid by its anastomoses with the infra-orbital, nasal and dental arteries ; and of the external carotid with the internal, by its anastomoses with the ophthalmic.
Internal branch cf the external carotid, Inferior pharyngeal artery, (a. pharyngea in ferior v. ascendens,) arises commonly from the internal side of the external carotid close to its origin, sometimes from the bifurcation of the primitive carotid, more rarely from the internal carotid, and occasionally from the occipital ; sometimes its place is supplied by the inferior palatine or by branches from the trunk of the facial; sometimes it is double, in which case only one of its branches arises from the external carotid, the other being furnished by one of the smaller arteries already mentioned, or by the internal carotid ; this artery is always the smallest branch of the external carotid; it passes perpendicularly upwards internal to the external carotid between the trunk of that vessel and the pharynx, lying on the rectus capitis anticus major muscle, and closely re lated to the superior cervical ganglion of the sympathetic. 'laving furnished branches from
its inner side, both ascending and descending, to the constrictors of the pharynx and other muscles, which also supply the mucous mem brane, and from its external side to the deep muscles of the neck, it terminates at the basis cranii, near the petrous portion of the temporal bone, by giving off its terminal branches, of which one, the proper pharyngeal, is princi pally distributed to the parietes of the pharynx, and communicates by anastomosis with the inferior palatine from the superior thyroid ; a second, the posterior meningeal artery, enters the cranium by the foramen lacerum posterius, or by an opening in the vicinity of the condyle of the occipital bone, and is distributed to the dura mater lining the inferior occipital fossa : and a third ascends to the basis cranii, and per forates the cartilaginous lamella, which fills up the foramen lacerum posterius, to enter the cranium and be distributed to the dura mater.