Lateral Wall of the Cavum Nasi in Man. 



677 



Does the embryology- account for the varying adult relations 

 of the nasofrontal duct and the sinus frontalis, with the structures 

 in the ventral and superior portion of the meatus nasi medius? 

 To this question I must give an affirmative answer, because I 

 think that careful analyses of this region in a series of adult 

 specimens justifies our embryological conclusions. 



Frontal furroiet (an- , — , 

 lages of anterior^ / fj 

 ethmoid cefh) ' -' 



Men tilt na») tnedius 



Duclta naiolaerimalu 



Fig. 44 (X 3.9) Drawing of a frontal section through the nose of a term fetus 

 (series D, slide 4). The frontal furrows have pouched towards the frontal region 

 and have established early anterior ethmoid cells. The frontal recess is obliter- 

 ated by the coalescence of the frontal folds with the lateral surface of the concha 

 nasalis media — compare with fig. 36 B. 



It will doubtless aid in making the adult conditions one meets 

 more comprehensible if we here refer to specific fetal conditions. 

 In fig. 41 the infundibulum ethmoidale is in line with the third 

 frontal furrow, but not directly continuous with it. If in this 

 case the frontal sinus should develop from the anterior ethmoid 

 cell of the first or second frontal furrows, or from the frontal 

 recess directly, the nasofrontal duct of the adult sinus would 

 doubtless communicate directly with the meatus nasi medius 



