Lateral Wall of the Cavum Nasi in Man. 687 



and also encroach upon the lumina of the frontal sinuses. Should 

 the intervening walls break down we would have established a 

 communication between either of the sinuses and certain of the 

 ethmoidal cells. Ethmoid cells very frequently extend into the 

 ventral extremity of the concha media, into the ventral extremity 

 ofthe processus uncinatus, and into the agger nasi. The bulla 

 ethmoidahs is almost invariably shell-like because of air cells. At 

 times the concha nasalis media contains multiple air cells or it 

 may contain a very large single cell which causes the concha to 

 look bleb-like. It is very common for the posterior ethmoid cell 

 which develops from the ventral and superior extremity of the 

 meatus nasi superior to extend beyond the limits of the lateral 

 ethmoidal mass into the concha media. Sometimes a cell develops 

 from the so-called sinus of the concha media, which more or less 

 hollows out the ventral extremity of the concha. Anterior eth- 

 moidal cells may also extend into the concha media. The cells 

 that extend into the agger nasi and processus uncinatus may com- 

 municate either with the meatus medius directly or with the supe- 

 rior and ventral extremity of the infundibulum ethmoidals The 

 concha nasalis media at times curls laterally and superiorly and 

 thus forms the so-called sinus of the middle concha. This curl- 

 ing is, however, not extensive as a rule and the area included by it 

 always opens freely into the middle meatus. It is usually unim- 

 portant. 



These conchal cells have led to conflicting and some erroneous 

 theories as to their genesis. They surely are nothing other than 

 ethmoidal cells which have developed beyond the limits of the 

 lateral ethmoidal masses into the appendages of these masses, i.e., 

 into the conchae. Occasionally a cell develops into the concha me- 

 dia which has its anlage-point on the lateral surface of this concha 

 (figs. 34 and 35). 



These conchal cells may become the seat of pathological con- 

 ditions, just as do the other paranasal chambers, but the cells do 

 not in any manner owe their origin to such conditions. For a fur- 

 ther consideration on conchal cells the reader is referred to a pre- 

 vious paper bearing directly on these cells. 



