The Ear. 449 



through the same channels with, in addition, the petro- 

 squamosal fissure, and thus induce meningitis, or cerebral 

 or cerebellar abscess, or, it may spread, posteriorly, to the 

 mastoid and cause mastoiditis, with, possibly, secondary 

 involvement of the cranial contents through the veins that 

 pass through the roof of that cavity. In mastoiditis, in- 

 flammation of the skin and other tissues over the mastoid 

 may develop from the venous communication that exists 

 between the exterior and the cavity. The involvement of 

 these tissues over the mastoid is especially prone to occur 

 in young children, since, in them, the outer wall of the 

 mastoid is exceedingly thin. 



The exposed position of the chorda tympani renders 

 it liable to injury in otitis media, with the result, that dis- 

 turbance of taste occurs in the anterior portion of the 

 tongue on the affected side, while caries of the inner wall 

 may cause neuritis of the facial nerve, which runs in a 

 canal in this wall, with resultant facial paralysis. 



Possibly otitis media may be reflexly associated with 

 dentition, through irritation proceeding to the tympanic 

 plexus of nerves from the superior and inferior maxillary 

 nerves that supply the teeth. The path, in this case, 

 may be through the superior maxillary to the 

 spheno-palaitine ganglion and then through the Vi- 

 dian nerve, which runs from this ganglion, as a part 

 of the great superficial petrosal nerve, to the tympanic 

 plexus. If the inferior maxillary nerve were involved, 

 then the path might be to the otic ganglion and thence 

 through the small superficial petrosal to the tympanic 

 plexus. In the treatment of otitis media, Politzer's air- 

 bag is used to inflate the middle ear through the Eusta- 

 chian tube. Normally, this tube is closed except during 

 swallowing, when it is opened by the tensor palati, the le- 

 vator palati and the salpingo-pharyngeus muscles ; hence, 



