540 



THE BLOOD VASCULAR-SYSTEM 



vessel of the opposite side; but the anastomosis is so minute that when one lingual artery is 

 injected the injection merely passes across to the opposite side at the tip of the tongue; and when 

 the tongue is divided accurately in the middle line, as in the removal of one-half of that organ, 

 practically no haemorrhage occurs. 



(3) The sublingual artery [a. sublingualis] (fig. 448) usually comes off from the hngual at the 

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

 which it supplies, and finally it usually anastomoses with the submental artery, a branch of 

 the external maxillary (facial). It also supplies branches to the side of the tongue, and gives 

 off a terminal twig, which anastomoses beneath 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 (fig. 448). 



(4) The deep lingual [a. profunda linguae], the termination of the lingual, courses forward 

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

 to the genio-glossus, between that muscle and the inferior lingualis, and is accompanied by the 

 lingual vein and terminal branch of the lingual nerve. It follows a very tortuous course, so 

 that it is not stretched when 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 opposite 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. 



Fig. 448. — Scheme of 



THE Right Lingual Artery. (Walsham.) 

 Glosso-palatinus 



Descending palatine 

 artery 



Pharyngo-palatinus 

 Palatine tonsil 



Ascending palatine 

 branch of external 

 maxillary 

 Tonsillar branch of 

 dorsal lingual 

 Tonsillar branch of 

 external maxillary 

 Stylo-glossus 



Dorsal lingual artery 

 Middle constrictor - 

 Hypoglossal nerve 

 External maxillary 

 artery 

 Posterior belly of digas- 

 tric and stylohyoid 

 Hyoid branch of lingual 

 Sup. laryngeal n. 

 Hyoid branch of sup. 

 thyreoid 

 Internal carotid artery 



Deep lingual artery 



Genio-glossus 



Artery of fraenulum 

 Hyo-glossus 



Sublingual artery 



Genio-hyoid 

 Anterior belly of 



digastric 

 Submental artery 



Superior thyreoid artery 



External carotid artery 

 Common carotid artery 



i 



4. THE EXTERNAL MAXILLARY (FACIAL) ARTERY 



The external maxillary or facial artery [a. maxillaris externa] (fig. 449) arises 

 immediately above the lingual from the fore part of the external carotid, at times 

 as a common trunk with the lingual. It courses forward and upward in a tortuous 

 manner to the mandible, and, passing over the body of this bone at the anterior 

 edge of the masseter muscle, winds obliquely upward and forward over the face 

 to the medial angle of the eye, where it anastomoses, under the name of the 

 angular artery, with the dorsal nasal branch of the ophthalmic. It is usually 

 divided into two portions — the cervical and the facial. 



The cervical portion (fig. 449) ascends tortuously from its origin from the 

 external carcjtid upward and forward 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 forward for a short way beneath the jaw, either 

 imbedded in or lying under the submaxillary gland. It has here the mylo-hyoid 

 and stylo-glossus beneath it. On leaving the cover of the gland it forms a loop 

 passing first downward and then upward over the lower border of the jaw imme- 

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

 ered 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 sub- 

 maxillary triangle, and, in addition to the structures already mentioned as cross- 

 ing it, is covered \)y the skin, superficial fascia, and platysma, and by one or two 

 submaxillary lymphatic nodes. The vein is separated from the artery by the 



