This section is from the book "Anatomy Of The Arteries Of The Human Body", by John Hatch Power. Also available from Amazon: Anatomy of the Arteries of the Human Body, with the Descriptive Anatomy of the Heart.
The Angular Artery is the terminating branch of the facial: it ascends between the two portions of the levator labii superioris alseque nasi, and anastomoses with the nasal or terminating branch of the ophthalmic artery. When it becomes necessary to make an incision into the lachrymal sac, it should be made external to the angular artery.
At its origin this vessel is covered by a few lymphatic glands, some of which accompany it on the face: these may enlarge and displace the submaxillary gland so as to occupy its natural position. A tumor of this kind maybe removed without dividing the trunk of the facial artery; and such has probably been the nature of the tumor in many of those operations that have been termed extirpation of the submaxillary gland. Mr. Colles doubts the possibility of removing it, on account of its connection with the facial artery, and its dipping behind the mylo-hyoid muscle; but a still greater difficulty arises from its vicinity to the lingual nerve, and its intimate connection with the gustatory nerve.
In certain amputations of a portion of the lower jaw, the artery is necessarily cut across, and care should be taken to divide it on the bone, and not beneath it, lest it should retract too deeply into the submaxillary space. Its coronary branches are divided in the operations for hare lip; it is not necessary to tie them, but the suture-needle must be passed sufficiently deep, and near the mucous membrane, in order to close the posterior part of the wound, as otherwise there might be serious hemorrhage into the mouth.
No artery presents greater varieties either as to origin, termination, size, or relations, than the facial; it sometimes arises in company with the lingual; in many cases it terminates by its coronary branches, and in others by the dorsalis nasi; in these cases the branches of the facial are replaced by those of the transversalis faciei: on the other hand, according to Soemmering, it may extend to the forehead, giving off the palpebral and lachrymal arteries. On one side there may be a large facial artery, and a mere rudimentary artery on the other.
The facial artery communicates with the internal maxillary by the infra-orbital and inferior dental branches of the latter, and with the internal carotid by its inosculation with the nasal branch of the ophthalmic.