TREPHINING THE INFERIOR MAXILLARY SINUS 29 



4-10, either in trephiniug 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 the patient permanently nervous about the 

 handling of its face. 



Hemorrhage is generally not severe and may occur from 

 the skin, where it may be readily controlled by compression 

 or ligation ; from the intra-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 gauze. These 

 tampons should be removed after twenty- four hours. 



5. TREPHINING THE INFERIOR MAXILLARY SINUS 



Figs. 3-11 



Uses and instruments. Same as in the preceding. 



Anatomical Outline. The inferior maxillary sinus is an 

 exceedingly irregular cavity, differing in details of form 

 and extent in individuals and at various ages. As shown 

 in the illustrations, its disposition might be compared to a 

 pair of saddle bags hanging over the nerve conduit, the 

 lateral and median chambers not very unlike in extent. 

 As suggested in Figs. 4, 5. the floor of the lateral cavity is 

 broken up by irregular bony septa, which in some cases cut 

 the sinus up into quite separate cavities. Sometimes it 

 extends downward barely below the end of the zygoma, 



