TREPHINING THE MAXILLARY SINUSES. 35 



forded into the mouth and the opening through the turbinated 

 bone be rendered unnecessary. 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 

 V and VI, either in trephining or after the sinuses have 

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

 cases entirely re.sorbed by pressure from dental cysts or other 

 causes, leaving the nerve stretched across the cavity as a 

 white nacrous cord, intensely sensitive. Any injury to this 

 nerve causes intense pain and renders the animal very re- 

 sistant to the necessary manipulations in the after care of 

 the wound and ma}' leave it permanently 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 

 controlled by pressure with absorbent cotton, by pushing a 

 small portion of the 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* controlled by packing with cheese cloth. 

 These tampons should be removed after twenty-four hours. 



