Lateral Wall of the Cavum Nasi in Man. 645 



Sometimes there is apparently no attempt at the formation of 

 individual conchae in the region of the ascending rami, hence in 

 these cases the meatuses — with the exception of the meatus medius 

 — do not possess individual ascending rami (fig. 23). In other 

 instances the meatus superior and medius have ascending rami, 

 but the remaining ethmoidal meatuses do not (fig. 25). The 

 ascending ramus of the meatus superior is occasionally so well 

 developed that it reaches nearly to the cribriform plate of the eth- 

 moid bone (fig. 24). 



A reference to figs. 21 to 30 will indicate the irregularity and 

 inconstancy of the ascending rami, with the single exception of 

 the meatus medius. Notwithstanding this inconstancy of the 

 ascending rami, we occasionally have ascending rami as well 

 marked as the descending rami (fig. 24). Rarely we find them all 

 fairly well marked (fig. 21), but in the vast majority of cases the 

 ascending rami of the supreme meatuses vary from an extremely 

 rudimentary state to a complete absence. The number of times 

 the ascending rami are present in some form, however, justifies 

 the division of the ethmoidal meatuses into ascending and descend- 

 ing portions. 



The descending rami. The descending rami of the ethmoidal 

 meatuses are as a rule much better differentiated than are the 

 corresponding ascending rami. What has been said of the ascend- 

 ing rami, i.e., a gradual change from an oblique to a more or less 

 vertical plane, as one passes from the meatus medius to the meatus 

 suprema HI, applies also, although with less degree, to the 

 descending rami. 



The descending ramus of the meatus medius lies practically in 

 a horizontal plane, and the corresponding ramus of the meatus 

 superior varies from it but little in its general direction (fig. 22). 

 On the other hand, the descending rami of the meatus suprema 

 I, II, and HI assume a more vertical direction — the latter being 

 most marked in the meatus suprema III (fig. 21). In very many 

 cases the descending rami of the meatus suprema II and 

 III are extremely rudimentary or not at all differentiated 

 (fig. 29). The descending ramus of the meatus suprema I is 

 present in some form, according to my specimens, in practically 



