 Hey everybody, Dr. O here. Let's talk about the para nasal sinuses. So what are they? They're hollow air filled spaces that are in certain bones of the skull. Their primary function is to lighten the skull but they also do play a role in residence which you know if you've ever, if you've ever been stuffed up it makes you sound a lot different. These sinuses are all covered or lined with nasal mucosa and at the mucosa production is increased and the sinuses get filled with fluid and that's going to change how you sound but also cause a lot of pressure and pain and discomfort. If you've ever had a sinus infection you know that's kind of a unique kind of pain. I've only had it one time and I certainly don't want to have any more. Alright let's go ahead and look at the sinuses so we'll start with their name for whatever skull bone they're actually in so the frontal sinus there at the top can either be the two like you see in this image or it can be one few sinus there. They're going to be the most anterior or the one that's closest to the front of your face. The largest sinus is the maxillary sinus. Sinus is also the one that is the most likely to be involved in sinus congestion and sinus infections these kind of things because of how they drain there since they're below the nose and the opening to where they drain is near the top. They're much harder to drain than the other sinuses so they can get filled up pretty easily. Next we have the sphenoid sinus so this is a single one. This is by far the most posterior of the sinuses. It's inside the sphenoid bone there and that's going to be the most posterior of your perinazle sinuses. Oh again, they're called perinazle sinuses because these are the ones that all connect to the nose just so you know. And then lastly we have the ethmoid air cells, these small little air sacs, these small spaces that are inside the ethmoid bone there. They're sitting right behind the superior nasal conche there in your nasal cavity. All right so those are your perinazle sinuses. Their functions are to lighten the bone and then play a role in sound production or resonance anyways and when there are problems they can get filled and lead to sinus congestion and sinus infections. I hope this helps. Until next time, be blessed.