DISSECTION OF THE HEAD AND NECK 305 



(db) Middle palatine nerve (N. palatinus medius) (0. T. external 



palatine). 

 (do) Posterior palatine nerve (N. palatinus posterior}. 



Near this note the tendinous expansion of the M. tensor 



veli palatini. 



Trace the N. nasopalatinus [Scarpae] also back to its origin. 

 A better view still of the pterygopalatine fossa will be obtained 

 if the orbital process (processus orbit alls) of the palate bone 

 and a portion of the body of the sphenoid bone be cut away with 

 bone-forceps. 



The terminal branches of the internal maxillary artery (A. 

 maxillaris interna) should now be finally reviewed. 



INTRAOSSEOUS COURSE OF N. FACIALIS, N. INTER- 

 MEDIUS, AND N. ACUSTICUS. 



The N. f acialis and N. acusticus should now be followed from 

 the internal acoustic meatus (meatus acusticus internus) in their 

 course through the interior of the petrous portion of the tem- 

 poral bone. 



Remove the temporal bone from the skull, fasten it firmly in 

 a vice in its natural position, and remove the squama temporalis 

 by sawing horizontally through it just above the level of the pars 

 petrosa. 



Make a second horizontal cut through the pars petrosa just 

 above the roof of the internal acoustic meatus ; the vestibule 

 (vestibulum), cavity of the tympanum (cavum tympani), and 

 mastoid cells (cellulae mastoideae) will thus be opened. Upon 

 the mastoid wall (paries mastoidea) will be seen a prominent 

 anteroposterior ridge (prominentia canalis f acialis), due to the 

 canal in which the facial nerve runs, the facial canal of Fallopius 

 (canalis f acialis [Fallopii]) (0. T. aqueduct of Fallopius). 

 Notice that with this is continuous a part of the canal upon the 

 labyrinthine wall of the cavum tympani, above and behind the 

 stapes and the fenestra vestibuli (0. T. foramen ovale). Gain 

 space by removing more of the roof of the tympanum (legmen 

 tympani) with bone-forceps ; open up the facial canal on the 

 labyrinthine wall (paries labyrinthica) with a chisel and expose 

 corresponding part of the N. facialis. Next expose the nerve in 

 the proximal portion of the facial canal by chiselling away the 

 roof of the internal acoustic meatus and following the nerve 

 along forward and lateralward. When the geniculate ganglion 



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