LING UA I.— FA CIA L 485 



branches with the vessel of the opi)()site side; l)ut the anastomosis is so minute tliat 

 when one lingual artery is injected, the injection merely passes across to the opi)0- 

 site side at the tip of the tongue; and wlicn the tongue is divided accurately in the 

 middle line, as in the removal of one-half of that organ, practically no luemorrhage 

 occurs. 



(3) The sublingual artery (fig. 333) usually comes off from the lingual at the 

 anterior margin of the hyo-glossus. It passes beneath the mylo-hyoid to the 

 sublingual gland, which it supplies, and, perforating the muscle, anastomoses with 

 the submental artery, a branch of the facial. It also supplies branches to the side 

 of the tongue, and gives off a terminal twig, which anastomoses l)eneath the mucous 

 membrane of the floor of the mouth (to which it also gives twigs) with the artery 

 of the opposite side. The artery of the fraenum is usually derived from this 

 vessel (tig. 3.')o). 



(4) The ranine artery, the termination of the lingual, courses forwards beneath 

 the mucous membrane, on the under surface of the tongue, to the tip. It lies 

 external to the genio-hyo-glossus, between that muscle and the inferior lingualis, 

 and is accompanied by the ranine vein and terminal branch of the gustatory nerve. 

 It follows a very tortuous course, so that it is not stretched Avhen the tongue is 

 protruded. Branches are given off from it to the contiguous muscles and mucous 

 membrane. Near the tip of the tongue it communicates with its fellow of the oppo- 

 site side, as shown by the fact that when the lingual artery of one side is injected 

 the injection fluid passes into the branches of the artery of the other side. 



4. THE FACIAL ARTERY 



The facial artery (fig. 334) — also called the external maxillary — arises imme- 

 diately al)Ove the lingual from the fore part of the external carotid, at times as a 

 common trunk with the lingual. It courses forwards and upwards in a tortuous 

 manner to the lower jaw, and, passing over the body of this Ijone at the anterior 

 edge of the masseter muscle, winds ol)liquely upwards and forwards over the face 

 to the inner canthus of the eye, where it inosculates, under the name of the angular 

 artery, with the nasal liranch of the ophthalmic. It is usually divided into two 

 portions — the cervical and the facial. 



The cervical portion (fig. 334) ascends tortuously from its origin from the 

 external carotid u})Avards and forwards beneath the posterior belly of the digastric 

 and stylo-hyoid muscles, and usually also beneath the hypoglossal nerve, and then 

 making a turn runs horizontally forwards for a short way lieneath the jaw, either 

 imbedded in or lying under the sul)maxillary gland. It has here the mylo-hyoid 

 and stylo-glossus beneath it. On leaving the cover of the gland it forms a l(Jop 

 passing first downwards and then upwards over the lower liorder of the jaw imme- 

 diately in front of the masseter muscle, where it is superficial, being merely covered 

 by the integument and platysma. Here it can be felt beating, and can be readily 

 compressed. In the above course it lies in the posterior part of the submaxillary 

 triangle, and, in addition to the structures already mentioned as crossing it, is 

 covered by the skin, superficial fascia, and platysma, and by one or two submaxil- 

 lary lymphatic glands. The vein is separated from the artery liy the submaxillary 

 gland, the posterior l)elly of the digastric muscle, the stylo-hyoid muscle, and the 

 hypoglossal nerve. 



The facial portion (fig. 334) of the facial artery ascends tortuously forwards 

 towards the angle of the mouth, i)assing under the })latysma (risorius) and zygomatic 

 muscles and the supramaxillary and buccal ])ranches of the facial nerve. It here 

 lies upon the jaAV and the l^uceinator muscle. Thence it courses upwards by 

 the side of the nose towards the inner canthus of the eye, being covered by the 

 levator labii superioris, levator labii superioris akvque nasi, and infraorlntal branches 

 of the facial nerve, and lying on the levator anguli oris (sometimes on the levator 

 labii superioris, instead of beloAV it) and the infraorbital branches of the fifth nerve. 

 The facial vein takes a much straighter course than the artery, is separated from it 

 by the zygomatic muscles, and lies to its outer side. 



