Numerous opinions have been expressed on the question of the function of the paranasal sinuses but without any general agreement. One reason for failure to arrive at a positive conclusion has been the mistake of considering the sinuses as a whole; if some separation be made between the various components, the explanation of their purpose is, in many instances, made clear.
I propose to approach the subject from the easiest aspect and to consider first those sinuses which appear to have a positive function; next to consider the sinuses left as unwanted spaces in previously functional areas; and thirdly to review sinuses for which no explanation can be found.
Sinuses of Positive Function
Provision of an Extensive Olfactory Region.
—If all vertebrates are reviewed, both as to habit and structure, it will readily be understood that a wide olfactory area is required by the majority, not only for the selection