9.2 The Nasal Cavity & Paranasal Air Sinuses Flashcards
What are the 5 functions of the nasal cavity?
- Sense of smell
- Resonating chamber for speech
- Warms and humidifies air
- Route for air into the lungs
- Traps and filters particles
What is the structure of the nasal cavity?
Medial wall (nasal septum)
2 lateral walls
Roof
Floor
What is the entrance to the nose called? (nostrils)
Nares
What is the region called where the nasopharynx opens into the oropharynx?
Choanae
What are the 3 regions of the nasal cavity?
Vestibule- skin (stratified squamous keratinised epithelia)
Respiratory- pseudostratified ciliated columnar epithelium
Olfactory- sense of smell
What bones contribute to the roof of the nasal cavity?
Nasal
Frontal
Ethmoid
Sphenoid
What bones contribute to the floor of the nasal cavity?
Maxilla
Palatine
Why are the lateral walls of the nasal cavity irregular?
Concha (turbinates) slow down air flow
Increase surface area
What bone makes up the superior and middle conchae?
Ethmoid bone
How many meatuses are there in the nasal cavity and what do they do?
Superior, middle and inferior
Responsible for drainage, connections with paransal sinuses and nasolacrimal duct
What happens to size of the conchae as you move downwards?
Become larger
What does the medial wall of the nasal cavity consist of?
Perpendicular plate of the ethmoid bone
Vomer bone
Septal cartilage
How do you access the pituitary gland surgically?
Transphenoidal surgery, through the sphenoid sinus
What is a septal haematoma?
Trauma to cartilage causes the perichondrium to be stripped off
Blood then accumulates between the cartilage and periochondrium
What can happen if a septal haematoma is not treated?
Can lead to avascular necrosis causing saddle nose deformity
How do you treat a septal haematoma?
Blood accumulation needs to be drained and then packed to prevent further accumulation of blood between perichondrium and cartilage
What cartilage is present on the nose?
Septal cartilage
Lateral
Major alar
Minor alar
Fibro-fatty tissue
What bones contribute to the lateral nose?
Maxilla
Nasal bone
What are the 3 parts of the nose?
Bridge
Dorsum
Tip
How common are nasal bone fractures?
Account for 50% of all facial fractures, protrudes and not particularly strong
What is visible in a nasal bone fracture?
Lots of swelling
Epistaxis
How do you treat a nasal bone fracture?
X-rays generally not needed as doesn’t change treatment
Follow up in several days in outpatient once swelling has settled
Nose may need to be reset if there are breathing issues
Rare complications can result in CSF leak and anosmia
Why is there a rich blood supply to the nasal cavity?
Allows the nose to humidify and warm incoming air
What is the most common site of epistaxis?
Kiesselbach’s area/Littles
All of the blood vessels join at this area
What are the blood vessels supplying the nasal cavity?
Anterior and posterior ethmoidal arteries- branches of the opthalmic artery ICA branch 1
Sphenopalatine artery
Greater palatine artery
(both branches of the maxillary artery, terminal branches of ECA)
Superior labial artery (septal branch)
How do you approach a nose bleed?
- Get patient to lean forwards and hold nose for 10-15 minutes, should hopefully clot if its an anterior bleed
- Next try cauterising the bleed using silver nitrate strips
- Try anterior packing of the nose
- Finally try posterior packing of the nose
- Call ENT may need surgery to repair especially if posterior bleed
What vessel is responsible for posterior nose bleeds?
Sphenopalatine artery, difficulty to stop have to try posterior packing, may have blood drip down into mouth
What is responsible for anterior nose bleeds?
Little’s/ Kiesselbach’s area
What is the sensory nerve supply to the nasal cavity?
Trigemnial nerve, opthalmic and maxillary branch
What are nasal polyps?
Benign swellings of the nasal mucosa
Who is affected by nasal polyps?
M:F 2:1
40< year olds
In children suggestive of cystic fibrosis
Normally bilateral
What do patients with nasal polyps experience?
Nasal congestion
Rhinorrhea- runny nose
Hypo- or anosmia
Snoring
Post nasal drip, causing a cough
What are red flags of nasal polyps?
Unilateral polyp
Bloody discharge
May be indicative of nasal cancer
How do you treat nasal polyps?
Intranasal steroids
What is rhinitis?
Inflammation of the nasal mucosa
What are the two causes of rhinitis?
Infective- usually viral, use pain management and nasal sprays
Allergic- hayfever, animal hair etc.
use antihistamines
What are the symptoms of rhinitis?
Nasal congestion
Rhinorrhea
Sneezing
Post-nasal drip
Nasal irritation
What is a common cause of unilateral bloody discharge from the nose in a child?
Foreign body
What are paranasal air sinuses?
Air-filled spaces that are extensions of nasal cavity
Drain into meatuses via small channels (ostia)
What epithelium lines the paranasal sinuses?
Extension of nasal cavity, therefore respiratory mucosa, thus ciliated and secrete mucous
Why do infections of the nasal cavity affect the sinuses?
Sinuses are connected to the nasal cavity therefore can be involved, leading to sinusitis
Maxillary sinus is the most common sinus as the ostia are high up therefore mucous cannot drain easily and it becomes stagnant
What do paranasal air sinuses do?
Humidify and warm inspired air
Reduce weight of the skull
What are the different paranasal air sinuses?
Frontal sinus
Ethmoid sinus
Maxillary sinus
Sphenoid sinus
What sinuses drain into the middle meatus?
Frontal
Maxillary
Anterior ethmoid
What sinuses drain into the inferior meatus?
Nasolacrimal duct- tears
What sinus drains into the roof?
Sphenoid sinus
What sinuses recieve general sensory innervation from CNVa?
Frontal
Ethmoidal
Sphenoidal
What sinuses recieve general sensory innervation from CNVb?
Maxillary
Label the image
Paranasal air sinus image
What is acute sinusitis?
Inflammation of paranasal air sinuses caused by URTI
What is the pathophysiology of acute sinusitis?
Inflammation of respiratory mucosa causes swelling, reduced cilia movement and increased secretions
Ostia become blocked , sinus cannot drain mucous builds up in sinus causing increased pressure and pain
Can develop secondary bacterial infection
How long does sinusitis have to be to be acute?
Less than 4 weeks, normally resolves within 10 days
What is clinical diagnosis of acute sinusitis based on?
Recent URTI
Blocked nose and rhinorrhoea, may have green or yellow discharge
Pyrexia
Headache/ facial pain, in area of affected sinus, worse on leaning forward
How is acute sinusitis managed?
Conservatively, mostly viral cause, use painkillers etc.
0.5-2% may develop bacterial sinusitis
When is acute bacterial sinusitis the more likely diagnosis?
Symptoms particularly severe at onset
Symptoms lasts longer than 10 days, but less than 4 weeks
Symptoms that worsen after initial improvement, suggesting secondary bacterial infection
What bacteria cause bacterial sinusitis?
Steptococcus pneumoniae
Haemophilus influenzae
Moraxella catarrhalis
