Session 9 - anatomy of the nose Flashcards
what are the functions of the nose and the nasal cavity
sense of smell provides a route for inspired air filters inspired air-trapping particles in nasal hair mucous moistens and warms inspired air resonating chamber for speech
where is the nose do you find hair and mucous glands
in the inner part of the external norse
why is the nasal bone so susceptible to fractures and what is done following a fracture of the nose
it is very prominent
reposition the nose once swelling and inflammation has gone down
what happens to the flow of air as it goes through the nasal cavity
As air goes from nostril to nasal cavity the cross sectional area increases and the flow of the air decreases (air slowed down)
how can a pituitary tumour be accessed
can be accessed via the nose through the sphenoid
what type of mucous membrane lines the top of the nasal cavity
what do we find there
olfactory mucosa
where we find ends of the olfactory nerve to perceive smell
what type of epithelium is found in the nasal cavity
pseudostratified columnar ciliated epithelium
how is the lining of the nasal cavity adapted to its function
– Filters (mucous/cilia)
– Humidifies (watery secretions)
– Warms (rich blood supply)
what drains into the nasal cavity
paranasal sinuses nasolacrimal duct (drains eye) it is a communication between the orbit and the eye and explains why your nose runs when you cry
what is the floor of the nasal cavity
hard palate
failure to fuse is seen in cleft palate and this can form a communication between the nasal and oral cavities
what is the medial wall of the nasal cavity
nasal septum
what is the found on the lateral wall of the nasal cavity
bony projection called conchae (superior,middle and inferior) lined with respiratory mucosa
meatuses are found between the conchae
the paranasal air sinuses drain into the nasal cavity underneath the meatuses
how do the conchae aid the function of the nasal cavity
slows airflow by causing tubulence of airflow (irregular because of inwards projections)
increases surface area over which air passes
which bones form the roof of the nasal cavity
what happens if there is fracture here
frontal bone
crista gali and cribirform plate of ethmoid bone
sphenoid bone
CSF and blood can leak into the nasal cavity
what bones forms the medial wall of the nasal cavity
septum compromised of boney and cartilaginous parts
boney part made from perpendicular part of ethmoid bone and vomer bone
what is a spetal heamatoma
Trauma to nose can lead to buckling of septum and shearing of blood vessels
Cartilaginous part of septum takes blood supply from overlying perichondrium
Blood accumulates between perichondrium and cartilage
how can you develop a saddle nose deformity
Untreated septal haematoma leads to
avascular necrosis of cartilaginous septum
– Saddling of nasal dorsum (‘saddle-nose’
deformity)
important to tampoande and aspirate a septal heamatoma
Can also develop infection in the collecting
haematoma
– Septal abscess formation further increases likelihood of avascular necrosis of septum
which nerve carries general sensation from the nasal cavity
trigeminal nerve
opthamlic and maxillary divisions
what are nasal polyps
how does it present
symptoms
Fleshy, Benign Swellings of Nasal Mucosa
usually bilateral and common in those over 40
obstrcuts air flow
pale or yellow in appearance/fleshy and reddened
blocked nose and water rhinorrhoea
Post-nasal drip
Decreased smell and reduced taste
Unilateral polyp +/- blood-tinged secretion may suggest tumour
what is rhinitis
what can cause it
Inflammation of the nasal mucosal lining Many causes, all lead to similar symptoms – Nasal congestion – Rhinorrhoea (“runny” nose) – Sneezing – Nasal irritation – Postnasal drip • Common causes – Simple acute infective rhinitis (viral- the common cold!) – Allergic rhinitis (hayfever)
what is the blood supply to the nasal cavity
Arterial supply to nasal cavity arises from branches of ophthalmic artery and maxillary artery
– Arterial anastomoses in anterior septum (Kiesselbach’s area/plexus)
• Most common source of bleeding in epistaxis
what is the venous drainage of the nasal caivty
Venous drainage from nasal cavity into pterygoid venous plexus, cavernous sinus and facial vein
where do you commonly get nose bleeds
Kiesselbach’s area
where do you get nose bleeds less commonly
if you get bleeding as result of damage to the sphenopalatine area
nose bleeds here are potentially more serious and difficult to treat
what are the paranasal sinuses
Air filled spaces that are extensions of nasal cavity
– Rudimentary or absent at birth
Lined with respiratory muscosa (thus are also ciliated and secrete mucous)
Named according to bone in which they are found: four ‘pairs’
• Help humidify and warm inspired air
– Reduce weight of the skull
• All drain into the nasal cavity via small channels called ostia into a meatus
– Most into middle meatus
what is sinusitis
• Infections in nasal cavity can involve the para nasal sinuses (sinusitis)
– Maxillary sinus most commonly affected
which bones contain paranasal sinuses
and what is their innervation
frontal Va ethmoid Va sphenoid Va maxillary Vb the roots of upper teeth can sometimes project in maxillary sinus
what causes acute sinusitis
how is it diagnosed
what are the symptoms
An acute inflammation of lining of sinus
– Commonly infective and often secondary to viral infection of nasal cavity (common cold)
• Diagnosis usually based on history and examination
– Non-resolving cold or flu-like illness
– Pyrexia
– Blocked nose and rhinorrhoea +/- green/ yellow discharge
– Headache/ facial pain (in area of affected sinus)
• Worse on leaning forward
what is the pathophysiology of sinusitis
Primary infection (e.g. rhinitis) leads to
reduced ciliary function, oedema of nasal mucosa and sinus ostia and increased nasal
secretions
• Drainage from sinus is impeded
• Stagnant secretions within the sinus become ideal breading ground for bacteria-secondary
infection
why is the maxillary sinus most likely to get blocked in sinusitis
the opening from the maxillary sinus into the nasal cavity is very narrow
if you get a cold and get mucous oedema the drainage of the sinus becomes easily blocked
the sinus is continuously making producing mucous secretions which it cannot secrete into the nasal cavity
usually self limiting
