Questions about paranasal sinuses?

[scilearner]

Hello everyone,

 

First of all I have not seen a paranasal sinus for real, so I'm bit confused how it looks like.

 

 

For example the maxillary sinus. So to see it you have to cut half of maxilla from front right. Then it is covered by mucous membrane, is this mucos membrane on top of bone. What I'm asking is do you have cut the maxilla from behind as well to see the sinus, or only from the front. Thank you

 

I also don't understand the function of these sinuses. How do they reduce the weight of the front of the skull (the air filled cavities reduce weight is that it,rather than having bone). Also more importantly how do they resonate voice. When you speak how does air travel to them for resonance? Do they travel from trachea?

 

Thanks