sinus cavities - why?

[justinh]

I have sinus problems. My question is why? not why do I have problems but what is the biological use of these cavities?

[Duck_Duck_Goose]

Google, “purpose sinus cavities”, Hit #1.

http://id.essortment.com/sinustrouble_nnd.htm

The purpose of all of these cavities is a question of debate. Some experts claim that they serve no purpose whatever. Others, though, have identified the following as reasons why we have sinus cavities:

(1) They lighten the weight of the skull

(2) They improve the resonance of our voices

(3) They help to moisten as well as warm the air we breathe

(4) They help the body to rid itself of waste matter, such as mucous and phlegm

You’re welcome.

[Perderabo]

Here’s what a noted columnist had to say…

Why do we have sinuses?