The Sinus Maxillaris in Man. 355 
of which Giraldés and Zuckerkandl speak, is very evident in 
many specimens. I, however, believe with Zuckerkand|! that we 
must, in the majority of cases, look elsewhere than to a patho- 
logical process for the determining factor in this condition. 
In this connection it is important to note that out of the 34 
stnus maxillares having accessory ostia, 27 of them had positive 
relations with the sinus frontalis; i. e., the infundibulum eth- 
moidale continuous with the nasofrontal duct. This would 
indicate that 77 per cent of sinus maxillares having positive 
fronto-maxillary relations have accessory ostia communicating 
directly with the meatus nasi medius. 
Another explanation for this accessory ostium may be found 
in the fact that since the sinus maxillaris develops by the growth 
of the sae and resorption of surrounding bone, its walls have a 
tendency to become thinned out most at points of least resist- 
ance. Such a point is found in the membranous portion of 
the base of the sinus, where bone is entirely wanting—the usual 
seat of the accessory opening. The mucous membrane in this 
position may become thinned out to such an extent, by the 
growth of the sinus, that an opening is formed; thus establishing 
the ostium maxillare accessorium. 
Since the ostium maxillare opens into the infundibulum eth- 
moidale, and secondarily by way of the hiatus semilunaris 
into the meatus nasi medius, it is apparent that the ostium max- 
illare accessorium, with its more dependent location and direct 
communication with the meatus nasi medius, is more advanta- 
geously placed as a drainage opening for the sinus maxillaris. In 
some cases the ostium maxillare certainly seems inadequate— 
due to its position, relations, and size—to properly drain the sinus. 
Why then may we not say that this accessory ostium, in some 
cases, of necessity comes to be formed as a means by which the 
sinus maxillaris can more readily dispose of accumulated fluid? 
The process by which this is brought about need not necessarily 
be termed pathological. Doubtless more information is neces- 
sary on this point before we dare draw conclusions. 
Of course some specimens present accessory ostia which look 
decidedly pathological; and as Zuckerkandl points out some are 
