Nose, Nasal Cavity And Paranasal Sinuses

Question 1

What do the nose and nasal cavity do?

Answer 1

Sense of smell

Provides a route for inspired air

Filters inspired air- trapping particles in nasal hair or mucous

Moistens (humidifies) and warms inspired air

Resonating chamber for speech

Question 2

What is the external nose made from?

Answer 2

Cartilage

Nasal bone - susceptible to fracture because is very prominent

Question 3

What is the vestibule?

Answer 3

Space inside external nose.

Lined with skin containing sebaceous glands and hair.

This is where inspired air enters.

Hairs assist in filtering trapped air.

Question 4

What are the boundaries of the nasal cavity?

Answer 4

Roof: Cribiform plate

2 x lateral walls: with bony projections on

Floor: Hard palate (roof of the oral cavity)

Medial: Nasal septum

Question 5

Why is the lateral wall irregular?

Answer 5

Because it contains 3 bony projections called conchae.

Superior conchae
Middle conchae
Inferior conchae

Question 6

Why are the conchae in the lateral wall important?

Answer 6

They slow airflow by causing turbulence to allow for the air to be humidified. They also increase the surface area over which air passes and create 3 meatuses.

Question 7

Why do you normally breath out of nose?

Answer 7

As nose allows you to modify the air so you don’t dry out the mucosa.

Question 8

Other than conchae and meatuses, what else does the lateral wall contain?

Answer 8

Openings under the meatuses to allow for the drainage of paranasal air sinuses and the nasolacrimal duct into nasal cavity.

Question 9

What does the nasal septum consist of and how does this structure allow for the formation of a septal haematoma?

Answer 9

Cartilage and bone

Cartilage of nasal septum receives blood supply from overlying perichondrium

Injury to nose can buckle septum and shear blood vessels.

Blood accumulates sub-perichondrium depriving underlying cartilage of it blood supply -septal haematoma.

Question 10

What is a saddle nose deformity?

Answer 10

The consequence of an untreated septal haematoma.

It is avascular necrosis of cartilaginous septum causing saddling of nasal dorsum.

Can also develop infection in the collecting haematoma - septal abscess formation further increases the likelihood of avascular necrosis of septum.

Question 11

What cranial never carries general sensation from the nasal cavity?

Answer 11

Trigeminal (Va and Vb) -ophthalmic and maxillary

Question 12

Why is the nasal cavity highly vascular and lined with a mucous membrane?

Answer 12

Olfactory mucous membrane houses the olfactory receptor neurones to allow for smell.

The respiratory mucus membrane is made from pseudostratified columnar ciliated epithelium rich in goblet cells.
Mucus and cilia allow for air to be FILTERED, watery secretions allowed for air to be HUMIDIFIED and the rich blood supply allows for air to be WARMED.

Question 13

What are nasal polyps?

Answer 13

Fleshy, benign swellings of nasal mucosa.

Usually bilateral and common in over 40yrs

Pale or yellow in appearance / fleshy and reddened

Question 14

What are symptoms of nasal polyps?

Answer 14

Blocked nose and watery rhinorrhoea 
Post-nasal drip 
Decreased smell and reduced taste 
Snoring
Unilateral polyp +/- blood tinged secretions may suggest tumour.

Question 15

What is rhinitis?

Answer 15

A cold - an inflammation of the nasal mucosal lining

Commonly caused by acute infection or an allergic reaction

Question 16

What are the symptoms of rhinitis?

Answer 16

Nasal congestion 
Rhinorrhoea (runny nose)
Sneezing 
Nasal irritation 
Postnasal drip

Question 17

What is the arterial supply to the nasal cavity?

Answer 17

Branches of ophthalmic artery (from internal carotid) and maxillary artery (from external carotid).

They anastomose in the anterior septum in Keisselbach’s plexus (little’s area)

Question 18

where does Epistaxis most commonly come from?

Answer 18

Little’s area - plexus of blood vessles in vestibule.

Question 19

What is the venous drainage of the nasal cavity?

Answer 19

Pterygopalatine venous plexus.

Question 20

What are paranasal air sinuses?

Answer 20

Air filled spaces that are extensions of nasal cavity.

They are lined with respiratory mucosa and are named according to the bone in which they are found.

Question 21

What do the paranasal sinuses do?

Answer 21

Help humidify and warm inspired air - reduce the weight of the skull.

They all drain into the nasal cavity via small channels called ostia. Most drain into the middle meatus.

Question 22

What are the four paranasal air sinuses?

Answer 22

Frontal
Ethmoid
Sphenoid
Maxillary

Question 23

What is acute sinusitis?

Answer 23

Symptomatic
inflammation of mucosal lining of nasal cavity and paranasal air sinuses often secondary to a viral infection of the nasal cavity.

It is self-limiting and so treatment is symptomatic.

Question 24

What are the symptoms of acute sinusitis?

Answer 24

This is a clinical diagnosis based on history and examination,

Recent upper respiratory tract infection,
Blocked nose and rhinorrhoea +/- green/yellow discharge,
Pyrexia,
Headache / facial pain in area of affected sinus and worse on leaning forward.

Question 25

What is the pathophysiology of acute sinusitis?

Answer 25

Primary infection 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 26

What makes it more likely to be an acute bacterial sinusitis?

Answer 26

Symptoms particularly severe at onset

Symptoms over 10 days without improvements (under 4 weeks)

Symptoms that worsen after initial improvement - secondary bacterial infection.

Question 27

What are some common bacteria for acute bacterial sinusitis?

Answer 27

Steptococcus pneumonia,
Haemophilus influenza,
Moraxella catarrhalis