9. Anatomy Of Nose, Nasal Cavity And Paranasal Air Sinuses

Question 1

What are some general functions of the nose and nasal cavity?

Answer 1

Sense of smell
Provides route for inspired air
Filters inspired air - trapping particles in nasal air or mucous
Moistens and warms inspired air
Resonating chamber for speech

Question 2

What is the role of the vestibule?

Answer 2

Lined with skin containing sebaceous/sweat glands and hair - filters inspired air

Question 3

Describe the structure of the nasal cavity?

Answer 3

Has bony boundaries and is divided into left and right halves by midline septum

Question 4

What are the bony projections and spaces of the lateral wall?

Answer 4

Bony: Conchae - superior, middle and inferior
Superior and middle are part of ethmoid bone
Spaces: meatuses - superior, middle, inferior

Question 5

Why are there irregularities in the lateral wall?

Answer 5

Slows airflow by causing turbulence of airflow

Increases surface area over which air passes

Question 6

What do the openings under the meatuses allow?

Answer 6

Allow for drainage of paranasal air sinuses and nasolacrimal duct into nasal cavity

Question 7

Which bones form the roof of the nasal cavity?

Answer 7

Frontal bone
Nasal bone
Ethmoid bone - cribiform plate
Sphenoid bone

Question 8

How do surgeons access the pituitary gland?

Answer 8

Using an endoscope into the nose and passing through the sphenoid bone - transsphenoidal surgical approach

Question 9

What is the medial wall made up of?

Answer 9

Nasal septum - cartilaginous and bony (ethmoid bone and vomer bone)

Question 10

What is a septal haematoma?

Answer 10

Potential complication from nasal surgery
Trauma to cartilage, tearing of blood vessels, accumulation of blood that strips perichondrium away from cartilage
Starving cartilage of blood supply, cartilage can start to necrose

Question 11

What happens if a septal haematoma is not treated?

Answer 11

Saddle-nose deformity

No treatment leads to avascular necrosis of cartilaginous septum

Question 12

What is the nerve innervation to nose and nasal cavity?

Answer 12

Trigeminal nerve - mainly ophthalmic and maxillary divisions

Question 13

What is the lining of the olfactory region of the nasal cavity?

Answer 13

Olfactory mucous membrane - contains dendrites of olfactory nerves
Covers over roof of nasal cavity

Question 14

What is the lining of the respiratory region of the nasal cavity?

Answer 14

Respiratory mucous membrane - pseudostratified columnar ciliated epithelium rich in goblet cells
Filters
Humidifies
Warms

Question 15

What are nasal polyps?

Answer 15

Fleshy, benign swellings of nasal mucosa
Usually bilateral
Common >40 years
Pale or yellow in appearance/fleshy and reddened

Question 16

What are the symptoms of nasal polyps?

Answer 16

Blocked nose and water rhinorrhoea
Post-nasal drip
Decreased smell and reduce taste 
At higher risk of sinusitis 
Unilateral polyp +/- blood-tinged secretion may suggest tumour

Question 17

What is rhinitis?

Answer 17

Inflammation of nasal mucosal lining

Question 18

What are the symptoms of rhinitis?

Answer 18

Nasal congestion
Rhinorrhoea
Sneezing
Nasal irritation
Post-nasal drip

Question 19

What are the common causes of rhinitis?

Answer 19

Simple acute infective rhinitis

Allergic rhinitis

Question 20

What does the rich blood supply to the nasal mucosa allow for?

Answer 20

Allows for warming and humidification of inspired air

Question 21

What is the arterial supply to the nasal mucosa?

Answer 21

Branches of ophthalmic artery (anterior and posterior ethmoid) and maxillary artery (sphenopalatine and greater palatine)

Arterial anastomoses in anterior septum (Kiesselbach’s plexus)
- most common source of bleeding in epistaxis (pinch nose to stop)

Question 22

What is the venous drainage of the nasal cavity?

Answer 22

Into pterygoid venous plexus (also drainage to cavernous sinus and facial vein)

Question 23

What are paranasal sinuses?

Answer 23

Air filled spaces that are extensions of nasal cavity - rudimentary or absent at birth
Lined with respiratory mucosa

Question 24

What are the functions of paranasal sinuses?

Answer 24

Humidify and warm inspired air

Reduce weight of skull

Question 25

Where do the paranasal sinuses drain?

Answer 25

Drain into nasal cavity via small channels (ostia) into a meatus - most into middle meatus

Question 26

What are the different paranasal sinuses?

Answer 26

Frontal
Ethmoidal
Sphenoidal
Maxillary

Question 27

What are the important anatomical relations of the paranasal sinuses?

Answer 27

Nasal cavity
Orbit
Anterior cranial fossa

Question 28

Wha is the general sensory for the paranasal sinuses?

Answer 28

Branches of CNV
Va - frontal, ethmoidal, sphenoid
Vb - maxillary sinus

Question 29

What is acute sinusitis?

Answer 29

Symptomatic inflammation of mucosal lining of nasal cavity and paranasal air sinuses
Potential secondary to viral infection of nasal amity

Question 30

What is the clinical diagnosis based on history and examination of acute sinusitis?

Answer 30

Recent URTI
Blocked nose and rhinorrhoea +/- green or yellow discharge
Pyrexia
Headache/facial pain - worse on leaning forward

Question 31

What is the pathophysiology in acute sinusitis?

Answer 31

Primary infection leads to reduced ciliary function, oedema of nasal mucosa and sinus ostia and increased nasal secretions
Drainage form sinus is impeded
Maxillary sinus is most commonly affected
Stagnant secretions within the sinus become ideal breeding ground for bacteria

Question 32

What are the most common bacteria in acute sinusitis?

Answer 32

Streptococcus pneumoniae
Haemophilus influenzae
Moraxella catarrhalis

Question 33

When is acute bacterial sinusitis more likely?

Answer 33

Symptoms particularly severe in onset
Symptoms >10 days without improvement
Symptoms that worsen after an initial improvement