NASOFRONTAL REGION IN MAN 



135 



moidale. If in figure 1 the sinus frontalis had developed from 

 the same frontal furrow as in figure 6, the relation between the 

 ductus nasofrontalis and the infundibulum ethmoidale would 

 have been less intimate. 



The dissection of the adult nasofrontal region illustrated in 

 figure 9 gives evidence of the early embryologic frontal furrows 

 or pits. The adult derivatives of the latter are readily identi- 



Cellulae ctk.erMt _ _ 

 Cellvlae etk.post. . 

 Sinus spJienoidalis 



Hj/pop7i7fsis cerebn 

 ConcJia ?ms. siipnmal 

 Conclia nas. sup. . 

 Ccj-'cJta 7tas. med. 



. Sinus froraails 



^^\P'obe in ductus nasofrontalis 



..Celhla^ eth. ant. 



, Concha uas. med. 



_ J7if?if/dih. eth 



Ostiujft 7/)axilJ/ire 



A- _ Jf-oc.7inci?iizt?/s 



4 



Fig. 7 From an adult. Recessus frontalis and nasofrontal connections ex- 

 posed for .study. Especially note the derivatives of the frontal pits, the tortuous 

 and narrow ductus nasofrontalis, and the termination of the ventral extremity 

 of the infundibulum ethmoidale. See text. 



fied. The first frontal pit developed into a small cellula eth- 

 moidalis anterior which is in direct communication with the re- 

 cessus frontalis by means of its ostium. The second and the third 

 frontal pits developed into sinus frontales (sinus frontalis in du- 

 plicate). Both of the latter communicate directly by means of 

 independent ostia with the recessus frontalis — no ductus naso- 

 frontalis being present. A study of the dissection shown in 

 figure 9 clearly points out that the infundibulum ethmoidale ter- 



