13. Nose, Nasal Cavity And Paranasal Sinuses

Question 1

The external nose consists of a bony component and a cartilaginous component. What two bones make up the bony component?

Answer 1

Nasal bone.

Frontal process of maxilla.

Question 2

How can the pituitary gland be accessed in surgery?

Answer 2

Via the nose, then through the sphenoid bone.

Question 3

What nerve innervates the olfactory mucous membrane lining the external nasal cavity?

Answer 3

CN I - olfactory nerve.

Question 4

What type of cells line the external nasal cavity?

Answer 4

Respiratory mucous membrane - so pseudo-stratified columnar ciliated epithelium.

Question 5

What is the role of the respiratory mucous membrane lining the external nose?

Answer 5

Mucous/cilia - filters air.
Watery secretions - humidifies air.
Rich blood supply - warms air.

Question 6

What drains into the nasal cavity?

Answer 6

Paranasal sinuses.

Nasolacrimal duct draining the eye.

Question 7

What are the boundaries of the nasal cavity?

Answer 7

Roof - crista galli and frontal bone.
Floor - hard palate.
Medial wall - septal cartilage and nasal septum (vomer bone and perpendicular plate of ethmoid bone).
Lateral wall - meatuses and superior, middle and inferior conchae.

Question 8

What is a septal haematoma?

Answer 8

Trauma to the nose leading to buckling of the septum and shearing of blood vessels supplying blood to the cartilaginous part of the septum from the overlying perichondrium. Blood accumulated between the perichondrium and cartilage forming a haematoma.

Question 9

What causes a saddle-nose deformity?

Answer 9

Avascular necrosis of the cartilaginous septum of the nose as a result of an untreated septal haematoma.
Risk increased if develop infection in collecting haematoma.

Question 10

What cranial nerve carries general sensation from the nasal cavity?

Answer 10

CN V - trigeminal, Va and Vb (mainly).

Question 11

How do nasal polyps present?

Answer 11

Bilateral, pale or yellow in appearance/fleshy and reddened.
>40 years.
Blocked nose and watery rhinorrhoea, post-nasal drip, decreased smell and reduced taste.

Question 12

What would a unilateral nasal polyp with or without blood-tinged secretion maybe suggest?

Answer 12

Tumour.

Question 13

What is rhinitis and what symptoms does it lead to?

Answer 13

Inflammation of the nasal mucosal lining leading to nasal congestion, rhinorrhoea, sneezing, nasal irritation and postnasal drip.

Question 14

What are the two most common causes of rhinitis?

Answer 14

Simple acute infective rhinitis (common cold).

Allergic rhinitis.

Question 15

What artists does arterial supply to the nasal cavity arise from?

Answer 15

Branches of the ophthalmic artery and maxillary artery, with anterior anastomoses in the anterior septum.

Question 16

What is the most common source of bleeding in epistaxis?

Answer 16

Keisselbach’s plexus.

Question 17

Where do veins from the nasal cavity drain into?

Answer 17

Pterygoid venous plexus, cavernous sinus, facial vein.

Question 18

What artery in the morse posterior aspect of the nose causes a small minority of nosebleeds, but can be more serious and difficult to treat?

Answer 18

Sphenopalatine artery.

Question 19

What sinus is most commonly affected in sinusitis?

Answer 19

Maxillary sinus.

Question 20

How do the paranasal sinuses drain into the nasal cavity?

Answer 20

Via Ostia into a meatus.

Question 21

What are the names of the 4 pairs of paranasal sinuses? What nerve is each innervated by?

Answer 21

Frontal - Va.
Ethmoid - Va.
Sphenoid - Va.
Maxillary - Vb.

Question 22

What is acute sinusitis?

Answer 22

Acute inflammation of the lining of a sinus, commonly infective and often secondary to a viral infection of the nasal cavity.

Question 23

Give 3 signs/symptoms of acute sinusitis

Answer 23

Non-resolving cold or flu-like illness.
Pyrexia.
Blocked nose and rhinorrhoea with or without green/yellow discharge.
Headache/facial pain in the area of the affected sinus, which is worse on leaning forward.

Question 24

What leads to acute sinusitis?

Answer 24

Primary infection eg rhinitis, leads to reduced ciliary function, oedema of nasal mucosa and sinus Ostia and reduced nasal secretions. Drainage from the sinus is impeded, and stagnant secretions within the sinus become ideal breeding ground for bacteria secondary to infection.

Question 25

Give 4 functions of the nose and nasal cavity

Answer 25

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

Question 26

What is the function of conchae on the lateral wall of the nasal cavity?

Answer 26

Slows air flow by causing turbulence.

Increases surface area over which air passes so moister and more humid.