Lateral Wall of the Cavum Nasi in Man. 



693 



The duplication of the ostiwn maxillare. In a previous para- 

 graph I spoke of the double pouching of the primitive maxillary 

 sinus. By the distal fusion of the two pouches the points of 

 evagination would remain as the adult ostia maxillaria, yet the 

 adult cavity would be single. Other duplications of the regular 



Bulla ethmoldalis 

 Recesstis fron la lis 



Sin us fron fa lis 



Infundibttlum ethmoi 

 dale 



Processus 

 Mucinatus 



Fig. 46 A semidiagrammatic drawing of an adult lateral nasal wall. The con- 

 cha nasalis media is represented as partly cut away so as to expose the underlying 

 structures. Note the nasofrontal relations, and that there is no true nasofrontal 

 duct. The frontal sinus presumably developed by an extension of the frontal 

 recess directly. Compare this with the conditions represented in figs. 47, 48, and 

 49. 



maxillary ostium are doubtless caused in a manner similar to the es- 

 tablishment of the ostium accessorium, ^.e.,by the attenuation and 

 ultimate rupture of the mucous membrane in this position. The 

 same conditions prevail here as in the position of the ostium acces- 

 sorium, since it is in the immediate neighborhood. 



