84 



TOPOGRAPHICAL ANATOMY OF THE 



The lingual nerve, a branch of the mandibular, has been followed 

 between the internal pterygoid muscle and the mandible, and then 

 between the niylo-hyoid and stylo-glossal muscles. It finally divides 

 into two branches, superficial and deep. The superficial branch (ramus 

 superficialis) continues forwards on the medial surface of the sublingual 

 gland, and ends in the mucous membrane of the floor of the mouth and 

 the adjacent part of the tongue. A recurrent branch passes towards 

 the posterior part of the tongue and anastomoses with the lingual branch 

 of the glosso-pharyngeal. The deep branch (ramus profundus) bends 

 round the lower border of the stylo-glossal muscle and runs to the tip of 



M. pterygopharyngeus.^ 

 M. palatopharyngeus. ^ ^ 

 M. stylopharyngeus 



palatina ascendens. 

 M. chondro- X 



pharyngeus. ^ 

 M. thyreo- ^^^^ 



pharyngeus. --^^ ^ 

 N. laryngeus ^ 

 cranialis. 



X. glossopharyngeus. 

 , N. hypoglossus. 

 A. Hngualis. 



N. Hngualis (ramus profundus). 

 N. Hngualis 



(ramus superficialis). 



M. thyreoh^-oideus. 



M. hyoglossus. / 



Mm. sternohyoideus et omohyoideus. i 



M. keratohvoideus. 



j ' M. genioglossus. 



I Submaxillary duct. 

 M. geniohyoideus. 



Fig. 29.— Lateral aspect of the pharynx and tongue. 



the tongue on the lateral surface of the genio-glossal muscle. It supplies 

 the mucous membrane, and its twigs unite with the superficial branch 

 and the hypoglossal nerve. 



The teeth (Dentes).— A tooth consists of a crown (corona dentis) 

 visible above the gum, a neck (collum dentis) embraced by the o-um, 

 and a root or roots (radix [radices] dentis) embedded in the bony iooth 

 cavity (alveolus ^ dentalis). The crown has a chewing surface (facies 

 masticatoria), a surface covered by the lips or cheek (facies labialis : 

 facies buccalis), and a surface looking towards the tongue (facies 

 Hngualis). Generally a tooth touches its neighbour by a surface of 

 1 Alveolus (dim. of alvens) [L.], a small trough or cavitv. 



