694 



Jacob Parsons Schaeffer. 



The communication of the frontal sinus with the middle meatus 



"We previously considered the early conditions of the frontal re- 

 cess with especial reference to the frontal furrows found on its lat- 

 eral wall. Reference was made to the possible points of origin of 

 the sinus frontalis. It now remains briefly to consider the ventral 

 and superior portion of the meatus medius with especial reference 



Ductus nasofrontalis 



Bulla ethmoidalis 



Infundibulum ethmoi 

 dale 



Ostium maxillare 

 aecessoriutn 



Sinus fron ia lis 



Processus 

 uncinatus 



Fig. 47 A semidiagrammatic drawing of an adult lateral nasal wall. The con- 

 cha nasalis media is represented as partly cut away. Compare the nasofrontal 

 relations with those found in fig. 46. In this case there is a nasofrontal duct which 

 meets the infundibulum ethmoidale at an angle. Some of the secretion from the 

 frontal sinus would find its way directly into the meatus medius, and the remainder 

 would pass into the superior and ventral portion of the infundibulum ethmoidale. 

 The frontal sinus in this case presumably developed from an anterior ethmoid 

 cell. 



to the manner of communication of the frontal sinus with the 

 middle meatus in the adult, to see whether our earlier conclusions 

 on this portion of the lateral nasal wall were justifiable. We pre- 

 viously concluded that the frontal sinus might develop from the 

 frontal recess directly; from one or more anterior ethmoid cells 



