The Sinus Maxillaris in Man. 335 
bears a direct relation to the cavity, and in a slightly larger per- 
centage of cases the second premolar bears a similar relation. 
The three most constant teeth, however, in direct relation to the sinus 
are the three molars. When the sinus maxillaris is small the first 
molar must be omitted from the direct relation (figs. 12 to 16). 
Orbita 
S. Max. 
H.Sem. 
Proc. Unc. 
Fic. 11 (X .8). Photograph of a frontal section of an adult’s face in the 
region of the sinus mavillaris. Note the location of the ostium maxillare and th 
infundibulum ethmoidale. Although the section is not exactly a frontal one 
there is nevertheless a marked asymmetry in the size of the two sinus maxillares. 
There is also quite a difference in the relation of the sinus floor to the nasal floor 
on the two sides. 
S. Max., = sinus maxillaris; B. Eth., = bulla ethmoidalis; H. Sem., = hiatus 
semilunaris; Proc. Unc., = processus uncinatus; C. Info., = canalis infraorbi- 
talis; Inf. Eth., = infundibulum ethmoidale; O. M., = ostium maxillare. 
It is a fairly safe rule to follow that, when the canine fossa 
and the lateral nasal wall are simultaneously approximated, the 
canine and premolar teeth do not bear a direct relation to the 
sinus maxillaris. In such cases a perforator pushed through a pre- 
molar-tooth socket might readily enter the lateral nasal wall—even 
pass through it, passing entirely free of the sinus cavity. Again, if 
the perforator were pushed through the lateral nasal wall, inferior 
