Paranasal sinus Flashcards
what are the paranasal sinuses?
air-filled extensions of the respiratory part of the nasal cavity
how many paranasal sinuses are there and how are they named? what are they?
4 paired sinuses, named according to the bone in which they are located:
maxillary, frontal, sphenoid and ethmoid
function of sinuses?
not clear:
they may contribute to the humidifying of the inspired air
They also reduce the weight of the skull
when and how are sinuses formed?
formed in childhood by the nasal cavity eroding into surrounding bone
how do paranasal sinuses relate to nasal cavity?
outgrowths of the nasal cavity
where do paranasal sinuses drain?
they all drain back into nasal cavity (outgrowths)
where are openings to the paranasal sinuses found?
on the roof and lateral walls of the nasal cavity
what is the inner surface of the paranasal sinuses lined by?
respiratory mucosa
pseudostratified ciliated columnar epithelium with goblet cells
where are the frontal sinuses found?
These are the most superior in location, found under the forehead, always triangular-shaped
where do frontal sinuses drain into?
the nasal cavity via the frontonasal duct, which opens out at the hiatus semilunaris on the lateral wall
where do sphenoid sinuses lie?
relatively superiorly, at the level of the spheno-ethmodial recess
where are the sphenoid sinuses found?
more posteriorly, and are related superiorly and laterally to the cranial cavity
where do the sphenoid sinuses drain into?
drain out onto the roof of the nasal cavity
clinical relevance of sphenoid sinuses?
the pituitary gland can be surgically accessed via passing through the nasal roof, into the sphenoid sinus and through the sphenoid bone
ethmoidal sinuses? how many and where do they empty into?
There are three ethmoidal sinuses; anterior, middle and posterior. They empty into the nasal cavity at different places
