lecture 34 paranasal sinuses

air-filled spaces located within the bones of the skull and face

what are the paranasal sinuses?

four

how many paired paranasal sinuses are there?

centered around nasal cavity and communicate with nasal cavity

why are the sinuses termed "paranasal"?

ostia

what are the openings or passageways between the nasal cavity and the paranasal sinuses?

unknown

what is the exact function of the paranasal sinuses?

lighten weight of skull, humidity and condition inhaled air (role of NO), provide resonance chambers for phonation, provide areas for plastic deformation in cases of facial trauma

what are possible functions of the paranasal sinuses?

respiratory mucosa

what are paranasal sinuses lined by?

continuous mucous membrane that lines the nasal cavity, larynx, trachea, and bronchial tree

what is the respiratory mucosa?

simple columnar, simple squamous, ciliated columnar epithelium with mucin producing goblet cells and glands

depending on location, what are the different types of epithelial cell linings that might exist?

ciliated columnar epithelium

what does the respiratory membrane lining the paranasal sinuses primarily consist of?

maxillary sinus, frontal sinus, sphenoid sinus, ethmoid sinus

what are the four sets of paired sinuses?

sphenoid sinus

which paranasal sinus appears to be a single cavity but has a wall separating it into two?

anterior and inferior

where is the sphenoid sinus located in relation to the sella turcica?

maxillary sinus

what is the largest paranasal sinus?

early during embryological period

when does the maxillary sinus develop?

inferior to orbit in the maxillary bone

where is the maxillary sinus located?

maxillary sinus (r)

the root of which sinus forms the floor of the orbit?

irregular, 3 recesses and medial wall composed of cartilage

describe shape of maxillary sinus

high on medial wall so that it drains to middle nasal meatus

where is the ostium of the maxillary sinus located?

in frontal bone superior to eyes in the forehead

where is the frontal sinus housed?

fan-shaped

what is the shape of the frontal sinuses?

in the most inferior and medial aspect of the sinus

where are the ostia of the frontal cavities located?

middle nasal meatus

what do the frontal sinuses drain into?

sphenoid bone at center of head

where do the sphenoid sinuses originate?

due to variability in placement of septum

why are sphenoid sinuses asymmetric?

posterior and superior to superior nasal concha

where is the sphenoid sinus ostium located?

ethmoid bone, just deep to medial wall of orbit

where do the ethmoid sinuses arise?

ethmoidal air cells (jenna ♡s these)

which sinuses are groups of several distinct air cells that are pyramidal in shape and separated by thin bony septa?

anterior and posterior ethmoidal air cells

what are ethmoidal air cells grouped into?

ostium

each group of ethmoidal air cells has a separate ___

as outgrowths from nasal cavity

how do the sinuses develop?

false, can drain directly or indirectly

true or false: all of the paranasal sinuses drain directly into the nose

inferiorly

the nasal conchae are the three bony outgrowths that curve ___ from the lateral walls of the nasal cavity?

meatus

what is the space under each concha caled?

sphenoid sinuses

what drains into the spheno-ethmoidal recess?

posterior ethmoidal air cells

what drains into superior nasal meatus?

anterior ethmoidal air cells, frontal sinus, maxillary sinus

what drains into the middle nasal meatus?

nasolacrimal duct

what drains into the inferior nasal meatus?

aseptic

the paranasal sinuses should be ___

cilia

what moves secretions from sinuses to nasal cavity?

viral URIs causing rhinitis

what might cause inflammation that blocks ostia of the paranasal sinuses?

negative due to utilization of oxygen

when blocked, fluid build up in the paranasal sinuses and pressure in the sinuses becomes...

maxillary sinus

what sinuses are most likely to be affected?

pansinusitis

what is it called when all four sinuses become inflamed at one time?

more severe

how do the symptoms of pansinusitis compare to those associated with sinusitis?

bacteria from nasal cavity to be drawn into paranasal sinuses to set up bacterial infection

what does negative pressure in the sinus permit?

inflammation of mucosa of nasal cavity

what is rhinitis?

inflammation of mucosa of paranasal sinuses

what is sinusitis?

inflammation of paranasal sinuses and mucosa of nasal cavity

what is rhinosinusitis?

rhinitis and sinusitis rarely occur independently

why is the term rhinosinusitis preferred?

viral

sinus infections are usually ___ in nature

1. >95% 2. 50-70%

sinus infections are viral in nature in what percentage of 1. adult cases and 2. pediatric cases are

bacterial

what causes of sinus infections are less common?

several ostia open in close proximity

bacterial sinus infections may spread between sinuses because...

1. <5% 2. 30-50%

what percentage of 1. adult cases and 2. pediatric cases of sinusitis are bacterial cases?

Strep. pneumoniae (most common), H. influenzae, and M. catarrhalis

what are the most likely pathogens that cause bacterial cases of sinusitis?