TREPHINING THE MAXILLARY SINUSES. 33 



If the partition between the two sinuses is intact it may 

 be necessary to destroy it immediately above IM', Plate III, 

 in order to drain the median portion of the superior maxil- 

 lary sinus if that is required. If a molar has been removed 

 and in so doing the bony wall leading down from the nerve 

 conduit, NF, Plates IV-VII, destroyed in the operation, 

 sufficient drainage may be afforded into the mouth and the 

 opening through the turbinated bone rendered unnecessary. 

 It generally occurs in extensive empyema of the sinuses 

 that an opening in the turbinated bone takes place by 

 necrosis and in some cases affords the desired drainage 

 while in the majority the pathologic opening is so placed 

 that it is incomplete. Leave all wounds entirely open and 

 irrigate daily with antiseptic solutions. 



Dangers. Care must be exercised to not injure the 

 superior maxillary division of the trifacial nerve, NF, 

 Plates IV-VII, either in trephining or after the sinuses 

 have been opened. The bony conduit of this nerve is in 

 rare cases entirely resorbed by pressure from dental cysts or 

 other causes, leaving it stretched across the cavity as a white 

 nacrous cord, intensely sensitive. Any injury to this nerve 

 causes intense pain and renders the animal very resistant 

 to the necessary manipulations in the after care of the 

 wound and may leave it pernamently nervous about the 

 handling of its face. 



Hemorrhage is generally not severe and may occur from 

 the skin, where it should be controlled by compression or 

 ligation ; from the inter-osseous vessels, where it may be 

 checked by pressure with absorbent cotton, by pushing a 

 small portion of cotton into the channel of the vessel with 

 a needle or tenaculum or by plugging the vessel with a 

 conical piece of wood ; from the wounded turbinated bones 

 where it may be stopped by packing with cheese cloth. 

 These tampons should be removed after twenty-four hours. 



3 



