262 IMPORTANT ANATOMICAL LANDMARKS. 



the first or second molar tooth. It passes in close proximity 

 to the lower border of the inalar bone. The transverse 

 facial artery lies just above the duct, and an important 

 branch of the facial nerve, which supplies the buccinator 

 muscle, accompanies it along its upper edge. 



The antrum of the superior maxilla ma}^ easily be reached 

 by perforating the bone at the fossa on its anterior surface, 

 just over the second bicuspid tooth, or, through the alveolar 

 cavity from which a molar tooth has been extracted. 



The facial artery crosses the lower jaw obliquely towards 

 the angle of the lips, in front of the insertion of the mas- 

 seter muscle, the outline of which is distinguishable in most 

 subjects. In front of the angle of the inferior maxilla, the 

 finger will detect a superficial notch, in which, with rare 

 exceptions, the facial artery lies, and where its pulsations 

 may be felt. 



The mental foramen, from which issues the inferior den- 

 tal branch of the fifth nerve, is situated a little nearer to the 

 alveolar than the lower border of the inferior maxilla, at a 

 point corresponding to the canine tooth, or to the interval 

 between it and the bicuspid tooth. The supra and infra- 

 orbital and mental foramina, are not always in a vertical 

 line, one with the other, as is sometimes asserted. 



To explore the throat, the tongue should be slightly pro- 

 truded ; the mouth being widely open, the posterior fauces 

 and pharynx will be displayed by inspiring, and repeatedly 

 pronouncing the syllable " hah." 



The glands of the tongue may be advantageously studied 

 upon the living subject. 



The ranine arteries are situated at the bottom of the 

 frenum linguae, where it blends with the floor of the mouth. 

 The large size of the ranine veins, lying upon the under 

 surface of the tongue, should be noticed. On each side of 

 the lower border of the frenum, the Ewinian and Whartonian 

 ducts open. Their orifices in the centre of an obvious 

 papilla may be plainly seen. 



The tonsil is situated between the anterior and posterior 

 pillars of the fauces. In its natural and healthy condition 

 it hardly projects be} 7 ond these. The internal carotid 

 artery lies at its base, and is separated from it by an inter- 

 vening aponeurosis and by the constrictor muscle of the 

 pharynx. This interval is, however, of considerable thick- 

 ness. The angle of the inferior maxillary bone corresponds 

 externally in its situation to that of the tonsil internally. 



