SURFACE MARKINGS OF SPECIAL REGIONS OF HEAD ANu NECK 1297 



mouth outward the mucous membrane of the cheek can be inspected, and on this, 

 opposite the second molar tooth of the maxilla, is the little papilla which marks 

 the orifice of the parotid duct. 



In the floor of the mouth is the tongue (Fig. 1201). Its upper surface is convex 

 and is marked along the middle line by a shallow sulcus; the anterior two-thirds 

 are rough and studded with papilla?; the posterior third is smooth and tuberculated. 

 The division between the anterior two-thirds and the posterior third is marked 

 by a V-shaped furrow, the sulcus terminalis, which is situated immediately behind 

 the line of the vallate papillae. 



Anterior lingual gland 

 Lingual nerve 

 Art. profunda li 



Vena com. n. liypoglossi 

 Longitudinal is inferior 



Plica fimbriata 

 Vena com. n. hypoglossi 

 H^^ Frenulum 



Orifice of submax. duct 

 Plica sublingualis 



FIG. 1202. The mouth cavity. The apex of the tongue is turned upward, and on the right side a superficial 

 dissection of its under surface has been made. 



On the under surface of the tongue (Fig. 1202) the mucous membrane is smooth 

 and devoid of papillae. In the middle line, the mucous membrane extends to the 

 floor of the mouth as a distinct fold the frenulum the free edge of which runs 

 forward to the symphysis menti. Sometimes the ranine vein can be seen immedi- 

 ately beneath the mucous membrane, a little lateral to the frenulum. Close to the 

 attachment of the frenulum to the floor of the mouth, the slit-like orifice of the 

 submaxillary duct is visible on either side. Running backward and lateralward 

 from the orifice of the submaxillary duct is the plica sublingualis, produced by 

 the projection of the sublingual gland which lies immediately beneath the mucous 

 membrane. The plica serves also to indicate the line of the submaxillary duct 

 and of the lingual nerve. At the back of the mouth is the isthmus faucium, bounded 

 above by the palatine velum, from the free margin of which the uvula projects 

 downward in the middle line. On either side of the isthmus are the two palatine 

 arches, the anterior formed by the Glossopalatinus and the posterior by the Pharyn- 

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