Anatomy/Physiology of the Nose

Question 1

What are the nasal functions?

Answer 1

Warm and humidify air
Important for neonates (obligate nasal breathers)
Immune barrier
Smell
Drainage and aeration of middle ear through eustacian tube
Drainage of paranasal sinuses and lacrimal duct

Question 2

What is the function of the eustachian tube?

Answer 2

To drain and aerate the middle ear

Question 3

What is the function of the sinuses?

Answer 3

Reservoir of warm, humid air
Lighten skull
Crumple zones
Vocal resonance
Lined with same mucosa-immune barrier

Question 4

How is external nasal anatomy relevant in nasal trauma?

Answer 4

Broken bones move back before they heal but broken/bent cartilage cannot be easily unbent

Question 5

Describe the characteristics of a septal haematoma

Answer 5

Occurs post trauma
Almost always bilateral
Results in no blood supply to the septum and so the septum necroses, which leads to perforation

Question 6

What are the causes of septal perforations?

Answer 6

Septal haematoma
Drugs
Digital trauma

Question 7

What is the function of the nasolacrimal duct and where does it lie?

Answer 7

Acts as a drainage pathway of lacrimal secretions

Runs from the lacrimal sac to open underneath the inferior turbinate

Question 8

What are the different paranasal sinuses?

Answer 8

2 frontal
2 maxillary
Sphenoid
Ethmoid air cells (anterior and posterior)

Question 9

Where does the frontal sinus lie and where does it drain?

Answer 9

Lies behind the eyebrows

Drains into the frontal recess via the middle meatus

Question 10

Where do the ethmoid air cells lie and where do they drain to?

Answer 10

Honeycomb structure between eyes
Anterior ethmoids drain into the middle meatus
Posterior ethmoids drain into superior meatus

Question 11

What is the clinical relevance of the ethmoid sinuses?

Answer 11

Infection can spread to orbits

Question 12

How does the sphenoid sinus drain?

Answer 12

Drains via the sphenoethmoidal recess

Question 13

Where do the maxillary sinuses lie and where do they drain?

Answer 13

Lie behind each cheek

Drains via middle meatus

Question 14

What are the characteristics of sinusitis?

Answer 14

Sinosal mucosa easily inflamed
Can be caused by allergies or infection
Normally self limiting but can be chronic if inflammation blocks sinus drainage

Question 15

How is sinusitis managed?

Answer 15

Remove allergic triggers (antihistamines if necessary)
Treat infection
Reduce inflammation
Surgery- remove polyps caused by chronic sinusitis, open up drainage pathways

Question 16

How does the nose receive its blood supply?

Answer 16

From branches of the external carotid artery (sphenopalatine, greater palatine and superior labial) and internal carotid artery (anterior and posterior ethmoidal arteries)