Plate IV. 



Trephining of Facial Sinuses. 



Right side of face, viewed laterall}-, showing extent and 

 relations of the sinuses. O, orbital cavity ; SM, superior 

 maxillary sinus ; IM', median portion of inferior maxillary 

 sinus ; NC, nerve conduit of superior maxillary trunk of the 

 trifacial ; IM, lateral portion of inferior maxillary sinus ; F, 

 frontal sinus ; ST, opening through superior turbinated bone 

 for the establishment of drainage from the frontal and superior 

 maxillary sinuses into the nasal passage ; IT, opening through 

 iuferior turljinated bone for the establishment of drainage 

 from the median portion of the inferior maxillary sinus into 

 the nasal cavitv. 



