The Sinus Mawyillaris in Man. 361 
We have, therefore, a gutter-like channel, of varying depth and 
efficiency, communicating between the frontal region and the sinus 
maxillaris; including the sinus frontalis in 56 per cent of cases and 
some of the cellule ethmoidales anterior in nearly all cases. 
In the cases where the infundibulum ethmoidale does not end 
in a pocket dorsally (fig. 30), much of the fluid that would other- 
wise be directed into the sinus maxillaris by this pocket, passes 
from the dorsal termination of the infundibulum ethmoidale into 
the meatus nasi medius. This, however, makes little difference— 
the very fact that some of the fluid gets into the sinus maxillaris 
makes the condition similar to the above. It requires merely 
more time to accomplish the same end result—a filled sinus 
makxillaris. 
In case the ostium maxillare is not patent, the fluid after 
reaching the dorsal end of the infundibulum ethmoidale rises 
in the channel and finally passes through the hiatus semilunaris 
into the meatus nasi medius. 
That the sinus maxillaris, because of its position and relations, 
is a reservoir for some or all of the fluid coming to the DORSAL END 
of the infundibulum ethmoidale, is a fact that admits of no debate 
(the ostium maxillare being patent). 
IMPORTANT NERVE RELATIONS OF THE SINUS MAXILLARIS. 
The roof or orbital wall of the sinus maxillaris is traversed 
by the infraorbital suleus and the infraorbital canal. These 
passageways transmit the infraorbital vessels and nerve (con- 
sidering the maxillary nerve as the infraorbital nerve from the 
proximal end of the infraorbital sulcus on). As a rule the canal 
has comparatively thick walls, but in many cases the inferior 
wall of the canal is of a papery delicacy and is easily compressed 
against the contained nerve and vessels. Frequently the canal 
is replaced by a groove, with the opening of the groove directed 
towards the sinus mazxillaris. The  structures—infrarobital 
nerve and vessels—contained in the groove are merely covered 
with the mucous membrane of the sinus. 
The posterior superior alveolar (dental) nerves, branches of 
THE AMERICAN JOURNAL OF ANATOMY, VoL. 10, NO. 2. 
