Anatomy- Nasal cavities and Paranasal sinuses Flashcards
what is the function of the nasal cavity
patent conduit for air to get to nasopharynx
filtres air of particulates (vibrissae= small hairs)
humidifies air (glands, goblet cells)
warms inspired air (blood)
sense of smell (olfactory epithelium- CN 1)
what cranial nerve for sense of smell
1- olfactory nerve
what is the ala
wing of the nose
what is the root of the nose
below the brow ride (monobrow)
what separates the nostrils
septum
what makes up the skeletal parts of the bone
base of nose made from nasal bones
nasal and ala cartilage make up the rest
what in the nose does the frontal bone and maxilla bone make
the nasal processes (when face developing)
where are the nasal bones
inbetween the frontal and maxilla bones
what forms the medial aspect of the orbit
the ethmoid bone
what bone makes up the boney part of the septum
perpendicular plates of the ethmoid bone and the vomer
what in nose does the ethmoid bone form
parts of the roof, lateral walls and septum of nasal cavity
where in the ethmoid bone does the olfactory nerve sit
in the central part (the cribiform plate)
where do you find dura in the ethmoid bone
in the crista galli
what makes up the paranasal sinuses
air cells in the lateral portions of the ethmoid bone
where in the ethmoid bone is the nasal cavity
between the middle concha, superior concha and the perpendicular plate
what bone forms the upper palate
maxilla
is the superior concha nigger/small than the middle and inferior concha
concha get bigger as you go down: superior smallest, inferior biggest
what is in the sphenoid sinus
were pituitary sits in sella turcica
what spilts the left and right nasal cavities
the vomer
what fractures can disrupt the cribiform plate of the ethmoid
le fort II and III (both have ethmoid involvement) and basillar skull fractures
what is anosmia
loss of smell
what are the complications of a fracture disrupting the cribiform plate
anosmia
facilitate the spread of infection
(basillar can cause CSF rhinorrhoea)
what is a le fort I fracture
floating palate- maxilla, vomer and palatine involved
what lines the nasal vestibule (chamber under ala/ nostrils)
stratified squamous epithelium (keratonised to non keratinised)
what lines the nasal cavity
inferior and medial concha= respiratory epithelium (pseudostratified columnar epithlium with goblet cells)
superior concha= olfactory epithelium (bipolar olfactory cells)
what is olfaction
sense of smell
what is the olfactory pathway
receptor cells in olfactory epithelium
pass up through cribiform plate (like hairs of a toothbrush)
synapse with olfactory bulb (ganglion)
neurones pass along olfactory tract
to temporal lobe and olfactory areas
what cranial nerves dont go to the brainstem
1 and 2
what is the innervation of the nasal cavity
somatic sensory
top half (tip of nose to superior sinus)= V1 (ophthalmic division of trigeminal) = anterior ethmoidal nerve
lower half (area sided by vomer and inferior sinus) = V2 (maxillary division)= nasopalatine nerve
what is the anterior ethmoid nerve and where does it go
is a branch of the nasociliary nerve, a branch of CN V1
passes through the anterior ethmoidal foramen
what is the nasopalatine nerve and where does it go
branch of CN V2
passes through the sphenopalatine foramen
what do the anterior ethmoid and nasopalatine nerves sense
temp, pain and touch
what is the blood supply to the face and nose
originates from internal and external carotids
internal carotid gives: opthalamic (supplies orbit)
ophthalmic gives anterior and posterior ethmoidal arteries
external carotid gives: maxillary artery (temporal branch), facial artery (under chin- goes to medial aspect of orbit)
maxillary artery gives sphenopalatine and greater palatine ateries
from facial artery comes superior labial artery, lateral nasal and septal branches
what is kiesselsbacks area
site where anastomisis occurs between arterial contributions
located anteroinferiorly on nasal septum
what is epitaxis
a nose bleed
where do nose bleeds usually originate from
kiessebachs area (input from high pressure arteries)
what feeds into kiesselbachs area
Anterior and posterior ethmoidal are branches of the ophthalmic (ICA) which travel through the air cells
Sphenopalatine artery passes through the sphenopalatine foramen gives off a descending palatine which goes towards the greater palatine artery
Superior labial artery gives off the septal branch
Lateral nasal artery comes off the facial artery
what are the parts of the lateral nasal wall
sphenoethmoidal recess superior nasal concha (ethmoid bone) superior meatus middle nasal concha (ethmoid bone) middle meatus inferior nasal concha (own bone) inferior meatus
what is a meatus
spaces below each concha
what is the path of a nasogastric tube
past septum (watch for epitaxis)
past inferior nasal concha (pain from V2)
over hard palate and past soft palate
past
The opening of the eustachian/auditory/ pharyngotympanic tube (from the middle ear) in the lateral wall of the nasopharynx
when reach pharynx will need anaesthetic do stop gagging
oropharynx
laryngopharynx
oesophagus
what are turbinates
e.g. nasal conchae
cause turbulent airflow through the nasal cavity increasing the opportunity for humidifying, warming and filtering
what can impact nasal air flow
engorgement of the nasal mucosa
what causes nasal engorgement
erectile tissue (anteriovenous) (swelling of the mucosa) one side will be engorged for 1-5 hours then switch to other side
what are the paranasal sinuses
open spaces within bone in the nasal cavity: -frontal sinuses -ethmoidal air cells -maxillary sinuses -maxillary sinuses -sphenoid sinuses
what lines each paranasal sinus
respiratory epithelium (cilliated pseudostratified columnar epithelium with goblet cells)
what does the maxillary (para)sinus form
floor of orbit and lateral wall of nose and upper dental arch
where does the sphenoid sinus drain to
sphenoethmoidal recess
where do the posterior ethmoid air cells drain to
superior meatus
where do the frontal and maxillary sinuses and anterior ethmoidal air cells drain to
semilunar hiatus of the middle meatus (created by the curvature of the ethmiodal bulla)
where do the middle ethmoidal air cells drain to
ethmoidal bulla
where does the nasal lacrimal duct drain to
inferior meatus
what is below the superior meatus
the posterior ethmoidal air cells
where is the ethmoidal bulla
in the middle meatus
where does lacrimal fluid drain into the nose
the nasolacrimal duct which drains to the inferior meatus
what is sinusitis
inflammation of the mucosa in 1 or more of the paranasal sinuses
can be acute, sub chronic or chronic
where do the cilia waft mucous towards
the ostia
what cause sinusitis
Viral URTI can cause swelling of mucosa, reducing diameter of ostia (where mucous is swept towards)
Sinuses can become filled with infected mucous and pressure builds
when can sinusitis cause spread of infection to which nerve
if there is a break in the medial wall of the orbit then infection in sinuses can spread to optic nerve
where in sinusitis can pain be referred to
the teeth
what sinus is predisposed to infection and why
Maxillary sinus is predisposed to infection
Ostium of maxillary sinus is location superior in relation to its cavity (drains into middle meatus)
Cilia must work against gravity
what is an oro-antral fistula
communication between maxillary sinus and tooth socket
what are the complications of an oro-antral fistula
(usually caused by tooth extraction)
tooth infection can case sinus infections
sinus infections can present as tooth ache due to referred pain
