Session 9 - anatomy of the nose

Question 1

what are the functions of the nose and the nasal cavity

Answer 1

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

Question 2

where is the nose do you find hair and mucous glands

Answer 2

in the inner part of the external norse

Question 3

why is the nasal bone so susceptible to fractures and what is done following a fracture of the nose

Answer 3

it is very prominent

reposition the nose once swelling and inflammation has gone down

Question 4

what happens to the flow of air as it goes through the nasal cavity

Answer 4

As air goes from nostril to nasal cavity the cross sectional area increases and the flow of the air decreases (air slowed down)

Question 5

how can a pituitary tumour be accessed

Answer 5

can be accessed via the nose through the sphenoid

Question 6

what type of mucous membrane lines the top of the nasal cavity
what do we find there

Answer 6

olfactory mucosa

where we find ends of the olfactory nerve to perceive smell

Question 7

what type of epithelium is found in the nasal cavity

Answer 7

pseudostratified columnar ciliated epithelium

Question 8

how is the lining of the nasal cavity adapted to its function

Answer 8

– Filters (mucous/cilia)
– Humidifies (watery secretions)
– Warms (rich blood supply)

Question 9

what drains into the nasal cavity

Answer 9

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

Question 10

what is the floor of the nasal cavity

Answer 10

hard palate

failure to fuse is seen in cleft palate and this can form a communication between the nasal and oral cavities

Question 11

what is the medial wall of the nasal cavity

Answer 11

nasal septum

Question 12

what is the found on the lateral wall of the nasal cavity

Answer 12

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

Question 13

how do the conchae aid the function of the nasal cavity

Answer 13

slows airflow by causing tubulence of airflow (irregular because of inwards projections)
increases surface area over which air passes

Question 14

which bones form the roof of the nasal cavity

what happens if there is fracture here

Answer 14

frontal bone
crista gali and cribirform plate of ethmoid bone
sphenoid bone
CSF and blood can leak into the nasal cavity

Question 15

what bones forms the medial wall of the nasal cavity

Answer 15

septum compromised of boney and cartilaginous parts

boney part made from perpendicular part of ethmoid bone and vomer bone

Question 16

what is a spetal heamatoma

Answer 16

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

Question 17

how can you develop a saddle nose deformity

Answer 17

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

Question 18

which nerve carries general sensation from the nasal cavity

Answer 18

trigeminal nerve

opthamlic and maxillary divisions

Question 19

what are nasal polyps

how does it present

symptoms

Answer 19

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

Question 20

what is rhinitis

what can cause it

Answer 20

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)

Question 21

what is the blood supply to the nasal cavity

Answer 21

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

Question 22

what is the venous drainage of the nasal caivty

Answer 22

Venous drainage from nasal cavity into pterygoid venous plexus, cavernous sinus and facial vein

Question 23

where do you commonly get nose bleeds

Answer 23

Kiesselbach’s area

Question 24

where do you get nose bleeds less commonly

Answer 24

if you get bleeding as result of damage to the sphenopalatine area
nose bleeds here are potentially more serious and difficult to treat

Question 25

what are the paranasal sinuses

Answer 25

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

Question 26

what is sinusitis

Answer 26

• Infections in nasal cavity can involve the para nasal sinuses (sinusitis)
– Maxillary sinus most commonly affected

Question 27

which bones contain paranasal sinuses

and what is their innervation

Answer 27

frontal Va
ethmoid Va
sphenoid Va
maxillary Vb
the roots of upper teeth can sometimes project in maxillary sinus

Question 28

what causes acute sinusitis
how is it diagnosed
what are the symptoms

Answer 28

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

Question 29

what is the pathophysiology of sinusitis

Answer 29

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

Question 30

why is the maxillary sinus most likely to get blocked in sinusitis

Answer 30

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