196 THE HEAD AND NECK 



trickles down the middle meatus and passes into the naso- 

 pharynx. Assistance in the diagnosis is obtained by the use of 



FIG. 57. Radiogram of Skull, showing normal Maxillary and 

 Frontal Sinuses. 



transillumination and radiograms. In both, the diseased sinus 

 is more opaque than the healthy one (Fig. 58). 



The sinus may be approached for the purpose of drainage in 

 three ways : (a) The tooth at fault may be extracted and a hole 



