Editing Paranasal sinuses (section)

== Development ==
Paranasal sinuses form developmentally through excavation of bone by air-filled sacs ([[skeletal pneumaticity|pneumatic diverticula]]) from the [[nasal cavity]]. This process begins prenatally (intrauterine life), and it continues through the course of an organism's lifetime.

The results of experimental studies suggest that the natural ventilation rate of a sinus with a single [[sinus ostium]] (opening) is extremely slow. Such limited ventilation may be protective for the sinus, as it would help prevent drying of its mucosal surface and maintain a near-sterile environment with high [[carbon dioxide]] concentrations and minimal [[pathogen]] access. Thus composition of gas content in the maxillary sinus is similar to [[venous blood]], with high carbon dioxide and lower [[oxygen]] levels compared to breathing air.<ref name="physiology">{{cite web|url=http://jap.physiology.org/content/107/4/1195.long##|title=ARTICLES &#124; Journal of Applied Physiology|website=jap.physiology.org|access-date=2017-09-07}}</ref>

At birth, only the [[maxillary sinus]] and the [[ethmoid sinus]] are developed but not yet pneumatized; only by the age of seven are they fully aerated. The [[sphenoid sinus]] appears at the age of three, and the [[frontal sinus]]es first appear at the age of six, and fully develop during adulthood.<ref>{{cite journal |last1=Towbin |first1=Richard |last2=Dunbar |first2=J. Scott |date=1982 |title=The paranasal sinuses in childhood |journal=RadioGraphics |volume=2 |issue=2 |pages=253–279 |doi=10.1148/radiographics.2.2.253 |doi-access=free }}</ref>

===CT scans, radiographs (x-ray) and other illustrations===
<gallery>
File:CT Paranasal Sinuses Coronal MPR Soft Tissue Window.ogg|[[Coronal_plane|Coronal]] [[Computed tomography|CT]] scan of the paranasal sinuses (soft tissue)
File:CT Paranasal Sinuses Coronal MPR Bone Window.ogg|Coronal CT scan of the paranasal sinuses (bone)
File:Paranasal sinuses radiograph occipitofrontal.jpg|Paranasal sinuses radiograph (occipitofrontal)	
File:Paranasal sinuses radiograph occipitomental.jpg|Paranasal sinuses radiograph (occipitomental)	
File:Paranasal sinuses radiograph lateral.jpg|Paranasal sinuses radiograph (lateral)
File:3DPX-002305 Upper respiratory cast 3DFile Nevit Dilmen.stl|3D cast of maxillary, frontal, ethmoid and sphenoid sinuses, nasal cavity and hypopharynx
</gallery>