The Sinus Maxillaris in Man. Bie 
the whole amount passing into the meatus nasi medius. Cryer 
(94, ’01, 07), Fillibrown (96, 97), reported on fronto-maxillary 
relations. Lothrop’s investigations (98) show that in 47 per 
cent of cases the infundibulum ethmoidale is continuous with the 
nasofrontal duct, while 53 per cent show that the infundibulum 
ethmoidale has no connection with the sinus frontalis. ‘Turner 
(01) speaks briefly about the relation, and Wilson (’08) in his 
paper on the “‘ Variations of the Ostium Frontale’’ alludes to this 
important relation. Some clinicians have reported isolated 
cases where they believed the maxillary trouble secondary to 
preéxisting frontal trouble; without, however, attempting to 
explain any anatomical conditions which would justify the 
clinical conclusions. 
In order to secure the fronto-maxillary relations in the speci- 
mens at hand, I undertook a series of investigations; including 
special dissections, filling the sinus frontalis with a fluid to deter- 
mine the direction of drainage, and the determination of the effi- 
ciency of the infundibulum ethmoidale. 
It will be remembered that the infundibulum ethmoidale at 
its superior and ventral termination is either continuous with 
the nasofrontal duct; or ends blindly without dilation, or in an air 
cell. The cases where it is continuous with the nasofrontal duct 
or with the sinus frontalis directly, represent what will be here 
spoken of as the positive fronto-maazillary relations. Where the 
infundibulum ends blindly or in an air cell, the conditions will 
be spoken of as negative fronto-maxilary relations. 
According to the specimens I examined, the sinus frontalis 
may discharge fluid put into it in one of the following ways: 
a. By the nasofrontal duct or the sinus frontalis being 
continuous with the infundibulum ethmoidale (in some cases 
there is no nasofrontal duct and the sinus frontalis is directly 
continuous with the infundibulum ethmoidale) (positive relation) 
(fig. 28). 
b. By the nasofrontal duct communicating directly with the 
meatus nasi medius (negative relation) (fig. 29). 
c. By a combination of the above conditions—in which case 
the sinus frontalis had two nasofrontal ducts; one continuous 
