TREPHINING OF THE FRONTAL SINUSES 17 



the surgical principle that suppurating cavities should be 

 provided with ample drainage from the most dependent 

 part. The direction to leave the external wound open, at 

 first thought, seems antagonistic to general surgical princi- 

 ples but it should be remembered that the wound consists 

 only of the incision through the skin, connective tissue and 

 bone, penetrating a suppurating cavity, and that any object 

 which we can place in this opening can only serve to dam 

 back the secretions of the cavity and can not prevent them 

 from coming in contact with the wounded surface. It must 

 further be regarded that the respiratory mucosa of the 

 upper air passages is not irritated or injured in any 

 manner so far as we can observe clinically by the direct 

 admission of air into them through a trephine, or other 

 artificial opening, but, on the contrary, the suppuration in a 

 sinus is constantly aggravated by the retention of the pus 

 and exclusion of air, and recovery is facilitated by thorough 

 drainage and aeration. 



3. TREPHINING OF THE FRONTAL SINUSES 

 Figs. 3-11 



Uses. Fracture of the bony walls, necrosis, tumors. 



The ample communication below with the superior max- 

 illary sinus (See FE. Figs. 5 and 6) prevents the accumu- 

 lation of pus or fluids in the frontal sinuses even if formed 

 therein unless the superior maxillary sinus first becomes 

 filled and the contents back up into the latter. In empy- 

 ema of the frontal sinuses, trephining of them alone can 

 not give relief, but calls for a repetition of the operation on 

 the maxillary sinuses. 



Instruments. Razor, scissors, convex scalpels, artery 

 forceps, tenacula, probe, trephine, curette, gouge, Luer's 

 sharp bone forceps (rongeur forceps), hammer, chisel. 



