Anatomy Of The Nose, Nasal Cavity + Air Sinuses Flashcards
Functions of the nasal cavity
- smelling
- resonating chamber for speech
- infection prevention/filter (mucous + cilia)
- passage for air
- humidification + warming of incoming air
Extent of the nasal cavity
- entrance at nares (nostrils)
- ends at choanae (posterior nasal aperture)
Regions of the nasal cavity
Vestibule
Respiratory region
Olfactory region
Nervous supply to the nasal cavity
Trigeminal nerve V:
Opthalamic branch Va
Maxillary branch Vb
What is nasal polyps?
Benign swelling of the nasal mucosa
Normally bilateral
Presentation of nasal polyps
- nasal congestion
- rhinorrhoea
- hypo or anosmia
- snoring
- post nasal drip > cough
What is rhinitis?
Inflammation of the nasal mucosa
Symptoms of rhinitis
- nasal congestion
- rhinorrhoea
- sneezing
- post nasal drip
- nasal irritation
Types of rhinitis
Infective
Allergic
What are the paranasal air sinuses?
Air filled spaces that are extensions of the nasal cavity
Functions of the paranasal air sinuses
- Humidify + warm inspired air
- Reduce weight of the skull
What epithelia lines the vestibule of the nasal cavity?
Keratinised stratified squamous epithelia
What bones make up the roof of the nasal cavity?
Nasal bone
Frontal bone
Ethmoid bone
Sphenoid bone
What bones make up the floor of the nasal cavity?
Maxilla
Palatine bone
Functions of the concha
Slows down air flow
Increases SA for humidification
Types of conchae
Superior
Middle
Inferior
What are the nasal conchae?
- Bony plates located on the lateral wall of the cavity
- Superior, middle + inferior conchae
What are the meatuses of the concha?
- Three spaces located beneath the conchae
- superior, middle + inferior meatuses
What makes up the medial wall of the nasal cavity?
Septal cartilage
Perpendicular plate of ethmoid bone
Vomer bone
What makes up the lateral wall of the nasal cavity?
Conchae
What is a septal haematoma?
- due to trauma to cartilage > perichondrium is stripped off
- can lead to avascular necrosis
- causes saddle nose deformity
What causes saddle nose deformity?
Septal haematoma
Treatment of a septal haematoma
- drainage (prevents infection
- reattach perichondrium to re-establish blood slow
- prophylactic antibitoics
When would you use an x ray with a patient with a nasal bone fracture?
If you suspect complications e.g cranial fossa fracture
Blood supply to the nasal cavity
- anterior + posterior ethmoidial arteries (from ophthalmic artery)
- sphenopalatine artery (from maxillary artery)
- greater palatine artery (from maxillary artery)
- superior labial artery (from facial artery)
What is Kiesselbach’s area?
Area of nose where 5 different blood vessels anastomose
What is the Opthalamic artery a branch of?
Internal carotid artery
Blood supply to the lateral wall of the nasal cavity
Anterior + posterior ethmoidal arteries
Sphenopalatine artery
What is the maxillary artery a branch of?
External carotid artery
A nose bleed involving which artery is more concerning?
Sphenopalatine artery
What sinus is most commonly affected in sinusitis?
Maxillary sinus
Demographic of nasal polyps
Men
>40 years old
Cystic fibrosis
What is post nasal drip?
What can it cause?
- mucous drips from nose +accumulates in the back of the throat > irritation
- chronic cough
What is a worrying presentation if a patient has nasal polyps?
Why?
- unilateral
- bloody discharge
- potentially nasal cancer
What can cause allergic rhinitis ?
Hay fever
Pets
Dust
Which blood vessels anastomose at Kiesselbach’s area?
- anteior + posterior ethmoidal arteries
- sphenopalatine artery
- greater palatine artery
- superior labial artery
What type of epithelia lines the paranasal air sinuses?
Respiratory mucosa
Ciliated pseudostratified columnar epithelia
List the paranasal sinuses
Frontal sinus
Ethmoid sinus
Sphenoid sinus
Maxillary sinus
Sensory innervation to the paranasal air sinuses
- ophthalmic nerve Va: frontal, ethmoidal + sphenoid sinus
- maxillary nerve Vb: maxillary sinus
What does the middle meatus drain?
Frontal sinus
Maxillary sinus
Anterior + middle ethmoid sinus
What does the interior meatus drain?
Nasolacrimal duct
(Reason why your nose gets blocked when crying)
Cause of acute sinusitis
Viral URTI spreading to sinuses
What time period is classified as acute sinusitis?
< 12 weeks
Pathophysiology of acute sinusitis
- inflammation of respiratory mucosa > swelling, reduced cilia movement + ^ secretions
- ostia becomes blocked
-
fluid builds up in sinus
(can develop secondary bacterial infection 0.5-2%)
Treatment of acute sinusitis
- analgesia
- anti-pyrexia
- high dose steroid nasal spray for 14 days e.g. mometasone
- backup antibiotics if doesn’t resolve - phenoxymethylpenicillin
Treatment of chronic sinusitis (>12 weeks)
- saline nasal irrigation
- steroid nasal sprays or drops - mometasone
- functional endoscopic sinus surgery
- removal of nasal polyps if present
Diagnosis of acute sinusitis
- based on history + exam
- recent UTRI
- blocked nose
- rhinorrhoea
- pyrexia
- headache (worsens on leaning forward)
When would you suspect a patient has acute bacterial sinusitis?
- symptoms >10 days without improvement
- discoloured purulent nasal discharge
- high fever
- severe local pain
- symptoms worsen after an initial improvement
What organisms commonly cause acute bacterial sinusitis?
Streptococcus pneumonia
Haemophilus influenzae
Moraxella catarrhalis
Where are most sources of bleeds in epistaxis from?
Keisselbach’s area
(Anterior bleed)
Where are posterior bleeds in epistaxis from?
Sphenopalatine artery
Special sensory innervation of the nose
Olfactory nerve
What are predisposing factors to nosebleeds?
- age: children or older age
- dry air
- high altitudes
- allergies
- blood thinning medications
- recreational drugs
Managment of epistaxis
In order to
(If first fails, move onto next)
- direct pressure
- cautery (silver nitrate stick)
- anterior packing
- posterior packing +/- surgical innervation
Why is sinusitis most common in the maxillary sinus?
Ostia high up > harder to drain
What arteries supply both the medial + lateral wall of the nasal cavity?
Which only supply the medial?
Both:
- anterior + posterior ethmoidal arteries
- sphenopalatine artery
Medial only:
- greater palatine artery
- superior labial artery
Presentation of acute sinusitis
- Blocked nose
- Rhinorrhoea
- Pyrexia
- Headache which worsens on leaning forwards
Outline the structures involved in the drainage of tears
- lacrimal gland produces
. - lacrimal punctum
- lacrimal canaliculi
- lacrimal sac
- nasolacrimal duct
- nasal cavity
Clinical features of a deviated nasal septum
- a symptomatic septal deviation causes nasal obstruction, predisposes patient to sinusitis + epistaxis
- difficulty breathing
- facial pain and headaches
- sleep apnoea if severe
What does a deviated nasal septum increase your risk of and why?
- sinusitis: - deviation obstructs the ostium of para nasal sinus
- epistaxiss: drying air currents
Diagnosis of a deviated nasal septum
To confirm diagnosis a nasal endoscopy is done to get a detailed view and evaluate impact on airflow
CT can also be used
Management of a deviated nasal septum
- nasal irritation with saline
- advice on allergen avoidance
- intranasal corticosteroids e.g. beconase
- intranasal or non sedating oral antihistamines e.g. fexofenadine
- septoplasty
Clinical features of a nasal fracture
- pain, swelling, bleeding + brusing
- crunching or crackling sound when touching nose
- difficulty breathing through nose
- change in nose shape
- possibly CSF leak + anosmia
Simple vs compound nasal fracture
- simple: skin and mucosa intact
- compound: cartilage/bone exposed
