60 ANATOMY OF THE HEAD AND NECK. 



cervical and first dorsal nerves. We thus have four branch( 

 representing five original trunks. 



DISSECTION IX. 



The section known in the French amphitheatres as the coupe (hi 

 pharynx is now to be made. The trachea and oesophagus, being divi led 

 opposite the top of the sternum, are to be turned up over the face ; 

 the chisel is to be applied at the apex of the angle formed by the 

 upper part of these and the vertebral column, and, keeping it close to 

 the latter, the basilar process is to be broken through behind the sella 

 turcica: the skull is then to be separated into two halves, one ante- 

 rior and the other posterior, by a section with the saw carried behind 

 the styloid process and directed inward and a little forward ; the two 

 sides should be sawed separately and the two incisions should meet 

 where the basilar process has been cut through with the chisel; the 

 occiput and vertebral column will then constitute one of the pieces, 

 while the other will be made up of the face, tongue, trachea, and 

 pharynx. 



Upon the latter of these pieces, the student should exa- 

 mine the lips, to see the frena formed by the mucous 

 membrane and which attaches them to the lower and 

 upper jaws upon the median line. The orifice of Steno's 

 duct, in the cheek (p. 24), near the second molar tooth of 

 the upper jaw, should also be sought for and explored by 

 probing. 



PHARYNX. 



The lower jaw should be removed, except about half an inch ou 

 each side of the symphysis. The pharynx should be stuffed with tow, 

 cotton-wool, or like material ; and, when thus distended, the con- 

 strictor muscles will be easily dissected. 



The PHARYNX is the dilated upper extremity of the ali- 

 mentary* tube, extending from the cavity of the mouth to 

 the oesophagus, about four and a half inches ; its inner 

 surface is lined with mucous membrane, continuous with 

 that of the mouth and oesophagus, and its walls are formed 

 by muscles called constrictors. 



The constrictor muscles are three in number on each 

 side, and are so arranged that the lower overlaps the mid- 

 dle, and the middle the upper muscle ; they are attached 

 superiorly by an aponeurotic expansion to the base of the 

 skull, and anteriorly to the larynx, hyoid bone, tongue, and 

 bones of the nasal cavity. 



