How many sinus cavities do you have?

A healthily developed person has four pairs sinus
cavities:

Between the eyes: these ones are called the
ethmoid sinuses and they are located behind the bridge of the nose between the eyes.  We
are born with them, and as our bodies grow bigger so  do
they.

Forehead: the ones located above the eyes around the
forehead are called the frontal sinuses, and they develop at about seven years of
age.

Cheekbones: the maxillary sinuses are on either side
of your nostrils in the cheek bones, and like the ethmoid sinuses we are also born with
them.

Behind the eyes: the final pair of sinus cavities are
deep in the skill behind the ethmoid insures and the eyes.  These ones don't develop
until your teenage years.