THE MOUTH. 



931 



nected in the middle line to the gum of the corresponding jaw by a fold of mucous 

 membrane, the fr&num labii su^erioris and inferioris the former being the larger 

 of the two. 



The labial glands are situated between the mucous membrane and the Orbicu- 

 laris oris round the orifice of the mouth. They are rounded in form, about the 

 size of small peas, their ducts opening by small orifices upon the mucous mem- 

 brane. In structure they resemble the salivary glands. 



The cheeks form the sides of the face and are continuous in front with the lips. 

 They are composed externally of integument, internally of mucous membrane, 

 and between the two of a muscular stratum, besides a large quantity of fat, areolar 

 tissue, vessels, nerves, and buccal glands. 



The mu-- : nine lining the cheek is reflected above and below upon the 



gums, where its color becomes lighter ; it is continuous behind with the lining mem- 



Opening of nasal dvxL 



Bristle passed through 

 Stenson's duct. 



FIG. 552. Sectional view of the nose, month, pharynx, etc. 



brane of the soft palate. Opposite the second molar tooth of the upper jaw is a 

 papilla, the summit of which presents the aperture of the duct of the parotid gland. 

 The principal muscle of the cheek is the Buccinator, but numerous other muscles 

 enter into its formation viz. the Zygomatici, Risorius Santorini, and Platysma 

 myoides. 



The buccal glands are placed between the mucous membrane and Buccinator 

 muscle : they are similar in structure to the labial glands, but smaller. Two or 

 three of larger size than the rest are placed between the Masseter and Buccinator 

 muscles ; their ducts open into the mouth opposite the last molar tooth. They are 

 called iii'jlir ,/lmds. 



The gums are composed of a dense fibrous tissue closely connected to the 



