BRANCHES OF THE EXTERNAL MAXILLARY ARTERY 541 



submaxillary gland, the posterior belly of the diagastric muscle, the stylo-hyoid 

 muscle, and the hypoglossal nerve. 



The facial portion (fig. 449) of the external maxillary artery ascends tortuously 

 forward toward the angle of the mouth, passing under the platysma (risorius), 

 the zygomatic muscle, the zygomatic head of the quadratus labii superioris 

 (zygomaticus minor), and the zygomatic and buccal branches of the facial nerve. 

 It here lies upon the jaw and the buccinator muscle. Thence it courses upward by 

 the side of the nose toward the medial angle of the eye, passing over or under the 

 infraorbital and angular heads of the quadratus labii superioris, and under the 

 infraorbital branches of the facial nerve. It lies on the caninus (levator anguli 

 oris) and the infraorbital branches of the fifth nerve. The anterior facial vein 

 takes a straighter course than the external maxillary artery, is separated from it by 

 the zygomatic muscle, and lies lateral to it. 



Branches of the External Maxillary Artery of the Neck 



The branches of the external maxillary artery in the neck are: — (1) The 

 ascending palatine; (2) the tonsillar; (3) the glandular; (4) the submental. 



(1) The ascending palatine [a. palatina ascendens] (figs. 448, 449) — the first branch of the 

 external maxillary, but often a distinct branch of the external carotid — ascends between the 

 internal and external carotids, and then between the stylo-glossus and stylo-pharyngeus mus- 

 cles, and on reaching the wall of the pharynx is continued upward between the superior constrictor 

 and internal pterygoid muscles toward the base of the skull as high as the levator veli palatini, 

 where it divides into two branches, a palatine and a tonsillar. One of these branches, the pala- 

 tine, passes with the levator veli palatini over the curved upper margin of the superior constrictor 

 to the soft palate, where it is distributed to the tissues constituting that structure, and anasto- 

 moses with its fellow of the opposite side and with the descending palatine branch of the internal 

 maxillary, and the ascending pharyngeal, which vessel often to a great extent supplies the place 

 of this artery. The other branch, the tonsillar, supplies the tonsil and the Eustachian tube, 

 anastomosing with the tonsillar branch of the external maxillary (facial) and ascending pharyn- 

 geal arteries. The ascending palatine artery supphes the muscles between which it runs on its 

 way to the palate. 



(2) The tonsillar branch [ramus tonsillaris] (fig. 449) ascends between the stylo-glossus and 

 internal pterygoid muscles to the level of the tonsil, where it perforates the superior constrictor 

 muscle of the pharynx, and ends in the tonsil, anastomosing with the tonsillar branch of the 

 ascending palatine and with the other tonsillar arteries (fig. 448). It gives branches also to the 

 root of the tongue. 



(3) The glandular branches [rami glandulares] are distributed to the submaxillary gland 

 as the artery is passing through or beneath that structure. A small twig from one of these 

 branches usually supplies the submaxillary (TVliarton's) duct. 



(4) The submental artery [a. submentalis] (fig. 449) comes off from the external maxillary 

 as the latter vessel lies under cover of the submaxillary gland, and, passing forward on the 

 mylo-hyoid muscle between the base of the jaw and the anterior belly of the digastricus, supphes 

 these structures and the overlying platysma and integuments. It anastomoses with the sub- 

 lingual artery. The external maxillary also supphes the adjacent muscles of the neck. 



Branches of the External Maxillary Artery on the Face 



From the lateral or concave side of the artery are given off branches which 

 supply the masseter muscle and anastomose with the masseteric and buccinator 

 branches of the internal maxillary artery, the transverse facial artery, and the 

 infraorbital arteries. 



From the medial or convex side the following larger and named vessels are 

 given off : — (1) The inferior labial; (2) the superior labial; and (3) the angular. 



(1) The inferior labial artery [a labiahs inferior] arises at the angle of the mouth and runs in 

 the under Up within the substance of the orbicularis oris, close to the mucous membrane. It 

 anastomoses with the artery of the other side. Frequently an additional branch passes from 

 the external maxillary to the lower lip. 



(2) The superior labial artery [a. labialis superior] arising from the facial a httle higher 

 than the inferior, passes forward beneath the zygomaticus, and then, hke the inferior labial, 

 courses tortuously along the lower margin of the upper Up between the orbicularis oris and the 

 mucous membrane, about 1.2 cm. (| in.) from the junction of the mucous membrane and the 

 skin. It is usually larger than the inferior labial. It anastomoses with its fellow of the opposite 

 side, and gives off a smaU artery to the septum — arteria septi nasi. Compression of this vessel 

 wUl sometimes control haemorrhage from the nose. 



(3) The angular artery [a. angularis] (fig. 449) is the terminal branch of the external max- 

 illary. It supplies the nose and anastomoses at the medial angle of the eye with the dorsal nasal 

 branch of the ophthalmic. It is accompanied by the anterior descending vein from the scalp. 



