THE CELLULE ETHMOIDALES 

 Cr. eLl. 



57 



C. sup. 

 C.med. 

 N.i rx{ re^orb. -^ 



Cel.etH.pos-t. 

 Proc. 

 S.maoc. 



C.iTxi. 



FIG. 19. SPECIMEN FROM A CHILD ONE MONTH AND EIGHT DAYS OLD. (Series 



D, No. 2.) 



Posterior view of coronal section cut 16 mm. posterior to the nasion, showing 

 the extent of supero-inferior and lateral development of sinus maxillaris and 

 cellulse ethmoidales posterior. Note the proximity of developing teeth to the 

 orbital floor. Cr.gal., Crista galli; Cel.eth.post., cellulse ethmoidales posterior; 

 Proc.unc., posterior extremity of processus uncinatus; S.max., sinus maxillaris; 

 C.inf., concha inferior; N.infraorb., nervus infraorbitalis; C.med., concha 

 media; C.sup., concha superior. 



B.etK. 

 Os-t.b.etK.] 

 Cel.etK.poat. 



S.lrorct. 



ln.iorirf.etVx. 

 D o c-t .n &. .la-c.T*. 



FIG. 20. SPECIMEN FROM A CHILD FOUR MONTHS AND TWENTY-SEVEN DAYS 



OLD. (Series D, No. 5.) 



Lateral portions of frontal, ethmoidal, and maxillary areas have been re- 

 moved to show the extent of pneumatization. S.front., sinus frontalis de- 

 veloping from a furrow in the recessus cqnchalis; Infund.eth., infundibulum 

 ethmoidale; Duct.na.lacr., ductus nasolacrimalis; Ost.max., ostium maxillare; 

 S.max., sinus maxillaris; Cel.eth.post., cellula ethmoidalis posterior; Ost.b.eth., 

 ostium bulla3 ethmoidalis, opening into the suprabullar furrow; B.eth., bulla 

 ethmoidalis. 



