Head & Neck 1 - Nasal Cavity & Paranasal Sinuses Flashcards
what three bones make up the external nose?
frontal bones
nasal bones
maxillary bones
what holds together the different cartilaginous components of the external nose?
fibrofatty tissue
what are the anterior nares?
nostrils - anterior openings into nasal cavity
what components make up the ROOF of the nasal cavity?
frontal & nasal bones
cribriform plate of ethmoid bone
sphenoid bone
what components make up the FLOOR of the nasal cavity?
hard palate (formed by maxilla & palatine bony components)
what bones form the hard palate?
palatine process of maxilla
horizontal plate of palatine bone
what components make up the MEDIAL WALL of the nasal cavity?
septal cartilage (anterior)
perpendicular plate of ethmoid (superoposterior)
vomer (posteroinferior)
what components make up the LATERAL WALL of the nasal cavity?
lacrimal bones
frontal process of maxilla
superior, middle & inferior conchae
perpendicular plate of palatine bone
pterygoid plate of sphenoid bone
which one of the conchae is NOT part of the ethmoid bone?
inferior concha - is a separate bone
which of the conchae IS part of the ethmoid bone?
superior & middle conchae
what external structure marks the medial wall of the nasal cavity?
nasal septum
what two arteries give off branches that mainly supply the MEDIAL & LATERAL WALL of the nasal cavity?
internal carotid artery
external carotid artery
what 6 arteries supply the medial & lateral walls of the nasal cavity? (from the artery they arise from too)
internal carotid artery
- anterior ethmoidal artery
- posterior ethmoidal artery
external carotid artery
- sphenopalatine artery
- greater palatine artery
facial artery (branch of ECA)
- superior labial artery
- lateral nasal artery
what is the difference between the medial & lateral walls of the nasal cavity?
there isn’t one - both are supplied by the same branches of the internal & external carotid arteries
what structures does the lateral wall of the lateral wall of the nasal cavity consist of?
nasal conchae (3) - superior, middle, inferior
nasal meati (3) - superior, middle, inferior
each nasal meatus is under its corresponding concha - e.g. superior nasal meatus is under the superior nasal concha
what is the function of the nasal conchae?
- increase surface area for efficient airflow into lungs
- warming and humidifying air as it passes to the lungs - rich vascular supply in mucosal lining of nasal cavity
what is the Kisselbach’s plexus?
network of 5 arteries in the nasal cavity
- anterior ethmoidal artery
- posterior ethmoidal artery
- sphenopalatine artery
- greater palatine artery
- superior labial artery
what is epistaxis?
bleeding from the anterior part of the nasal cavity (nosebleed) - often originates from Kisselbach’s plexus
what is the clinical significance of Kisselbach’s plexus?
often the origin of nosebleeds
which of these arteries are NOT part of Kisselbach’s plexus?
A: anterior ethmoidal artery
B: lateral nasal artery
C: sphenopalatine artery
D: superior labial artery
B: lateral nasal artery
what is the general sense innervation for the nasal cavity?
ophthalmic & maxillary divisions of the trigeminal nerve (CNv1 & 2)
what is the special sense innervation for the nasal cavity?
olfactory nerve (CN1)
what type of epithelium covers the majority of the nasal cavity? what area is the exception and what is it covered by instead?
majority of nasal cavity - ‘respiratory epithelium’/ pseudostratified columnar ciliated epithelium
nasal vestibule is the exception - covered by stratified squamous epithelium
what is ‘respiratory epithelium’?
pseudostratified columnar ciliated epithelium
- appears to have multiple cell layers, but consists of a single layer
- has goblet cells which secrete mucus & ciliated cells sweep mucus away
what is the role of the stratified squamous epithelium in the nasal vestibule?
protects against friction & irritation
what are the 4 paranasal sinuses?
frontal
ethmoidal
sphenoidal
maxillary
(they’re all paired!!)
what are paranasal sinuses? what type of epithelium are they lined by?
air-filled cavities connected to the lateral walls of the nasal cavity
lined by pseudostratified columnar ciliated epithelium
what is the main source of blood supply to the paranasal sinuses?
A: branches of the internal carotid artery
B: branches of the facial artery
C: branches of the external carotid artery
D: branches of the common carotid artery
C: branches of the external carotid artery
what cranial nerve innervates the paranasal sinuses?
A: abducens nerve; CN6
B: facial nerve; CN7
C: trochlear nerve; CN4
D: trigeminal nerve; CN5
D: trigeminal nerve; CN5
what are the functions of the paranasal sinuses?
- lighten the skull (as air-filled cavities)
- increase voice resonance
3, help with immune defence of the nasal cavity - humidify inspired air
within what bone is the frontal sinus located?
within the frontal bone - superior to the orbit (eye socket)
where are the ethmoidal air cells/sinus located?
within the ethmoidal bone - form part of the medial wall of the nasal cavity
how many ethmoidal air cells are typically present within the ethmoidal bone?
3-18
- irregularly-shaped air-filled cavities, giving the ethmoid bone a honeycomb appearance
what are the three subdivisions of the ethmoidal air cells?
anterior
middle
posterior
where does the sphenoid sinus lie relative to the sella turcica (which houses the pituitary gland)? what does this mean clinically?
sphenoid sinus lies BELOW/INFERIOR to the sella turcica
clinically means the pituitary gland can be surgically accessed via the nasal cavity and sphenoidal sinus (transsphenoidal surgery)
where does the sphenoidal sinus lie relative to the nasal cavity?
sphenoidal sinus lies BEHIND the nasal cavity
where does the frontal sinus drain?
middle nasal meatus (via the frontonasal duct)
where does the anterior ethmoidal sinus drain?
middle nasal meatus (via the frontonasal duct)
where does the middle ethmoidal sinus drain?
middle nasal meatus (via ethmoid bulla)
where does the posterior ethmoidal sinus drain?
lateral wall of the superior nasal meatus
where does the sphenoidal sinus drain?
sphenoethmoidal recess (superoposterior to superior nasal concha)
where does the maxillary sinus drain?
middle nasal meatus (via the maxillary ostium)
which is the largest of the paranasal sinuses?
maxillary sinus
where is the maxillary sinus located?
within the maxilla
inferior to the orbit (eye socket)
superior to the upper teeth
why is drainage of the maxillary sinus often difficult?
ostium (opening) of the maxillary sinus is higher than the sinus floor - makes its natural drainage against gravity difficult
how does head positioning affect maxillary sinus drainage in individuals with sinusitis?
patients with maxillary sinusitis may feel relief when tilting their head - allows better alignment with gravity for drainage
which of the ethmoidal sinuses DON’T drain into the middle meatus? where does it drain instead?
posterior ethmoidal sinus - drains into lateral wall of the superior nasal meatus
which sinuses drain into the middle meatus? (4)
frontal sinus
anterior ethmoidal sinus
middle ethmoidal sinus
maxillary sinus
