THE MOUTH 



1101 



with the oral cavity proper (aside from the small interdental spaces) only through 

 a space behind the last molar teeth on each side. Opening into the oral cavity are 

 certain accessory glands, the salivary glands. 



Fig. 847. — Coronal Section through Oral Region. 



Maxillary sinus Nasal cavity 



/ 



Masseter 



Parotid 



duct 



Palatine 



glands 



Buccinator 



Vestibulum 

 oris 



~ Mandible 



Genio-glossus*' 



Genio-hyoid 



--Mandibular 

 canal 



— Sublingual 

 gland 

 ~~^ External 



maxillary art. 

 "~ Submaxillary gland 



^Sublingual art. and 

 lingual n. 



\Mylohyoid 

 Digastric 



Structure. — Of the typical layers of the alimentary canal, only the mucous membrane can 

 be recognised as a continuous layer in the mouth cavity. Even this is greatly modified and in 

 structm-e somewhat resembles the skin, from which it is derived and with which it is continuous 



Fig. 848. — Mid-sagittal Section of the Head, through Oral and Nasal Regions. 



(Rauber-Kopsch.) 



Cribriform plate 

 Spheno-ethmoidal 

 Hypophysis recess ] 



Dorsum sellae 



Choanal arch 

 Nasopharyngeal 

 meatus 

 Pharyngeal recess 



Torus tubarius 

 Levator cushion 

 Anterior lip 

 Salpingopharyn- 

 geal fold 



Uvula 



Foramen caecum 

 linguae 

 Palatopharyngeal fold 



Epiglottis 



Incisive canal 

 Upper lip 



Vestibulum oris 

 Oral cavity proper 

 Lower lip 



Sublingual mucous 

 membrane 



Hyoid bone 



Mental spine 



at the rima oris. The submucosa is a strong fibrous layer connecting the mucosa with adjacent 

 structures, and lodging numerous racemose mucous glands. The muscles in the walls of the 

 mouth cavity are not homologous with the typical muscularis of the alimentary canal. The 

 outer fibrous tunic is also wanting. 



