TREPHINING THE NASAL FOSSAE 31 



at other times it reaches down below the intra-orbital fora- 

 men. There is hence no rule by which the operator may 

 at all times make his opening precisely at the lower ex- 

 tremity of the sinus. 



Technic. The general technic is the same as for the 

 frontal and superior maxillary sinuses, but two trephine 

 openings should always be made. The first opening should 

 be made close against the median side of the zygoma near 

 its lower or nasal extremity, Fig. 3, IM, and the inferior 

 border lowered sufficiently with the bone forceps to provide 

 thorough drainage for the lateral compartment of the 

 sinus. 



The second opening is to be made on the median side of 

 the nerve conduit, NC, Figs. 4, 5, as indicated at IM' in 

 Fig. 3. The location may be accurately determined by pal- 

 pating with the index finger through the first opening at 

 IM, Fig. 3. This compartment can not be well drained 

 upon the face through either of the trephine openings, so a 

 third opening, penetrating the inferior turbinated bone at 

 IT, Figs. 4, 5, is essential to ideal results by affording free 

 drainage into the nasal chamber. The opening through 

 the inferior turbine is made in the same manner as de- 

 scribed for the opening through the superior turbine from 

 the frontal. Thorough search should be made throughout 

 the sinus for the causes of disease. Should diseased teeth 

 be present, remove these and follow by after treatment the 

 same as advised for the two preceding operations. 



6. TKEPHINING- THE NASAL FOSSAE 



Figs. 7-10 



Uses. Operations upon the septum nasi, or the turbi- 

 nated bones,or the removal of tumors or foreign bodies from 

 the nasal passages. 



