Nose and Paranasal sinuses

Question 1

What are the functions of the nose?

Answer 1

Olfaction (smell)
Respiration
Filter and humidify
Drain & eliminate paranasal sinus and nasolacrimal duct secretions

Question 2

Briefly describe the external nose.

Answer 2

Provides opening into nasal cavity

Bony and (predominantly) cartilaginous components

Nostrils bounded laterally by alae

Skin covering nose extends into the vestibule

Question 3

List the bones that constitute the external nose.

Answer 3

Nasal bone
Frontal process of maxilla
(Lacrimal bone?)

Question 4

List the cartilage of the external nose.

Answer 4

Septal cartilage
   - Lateral process of septal cartilage
   - Superior margin of septal cartilage
Major alar cartilage
Minor alar cartilage

Question 5

What is the most common facial fracture?

Answer 5

Nasal fracture

Question 6

Tell me a little bit about nasal fractures.

Answer 6

Most common facial fracture
History of force to the face
Deformity
Complications include septal haematoma

Question 7

What are the openings to the nasal cavity called?

Answer 7

Nares

Question 8

What are the passage ways from the nasal cavity to the nasopharynx called?

Answer 8

Choanae

Question 9

What bones contribute to the skeleton of the nose?

Answer 9

Frontal
Nasal
Ethmoid (plus its perpendicular plate)
Sphenoid
Vomer
Palatine process of maxilla
Horizontal process of palatine bone
Inferior concha

Question 10

What are the lateral walls of the nasal cavity?

Answer 10

Conchae (a.k.a. turbinates) (creates 5 passages within cavity - 1 unpaired and 3 paired) (made from ethmoid bone)
Openings into the nasal cavity
- Draining
   - Sinuses
   - Lacrimal apparatus
   - Middle ear

Question 11

What are on the medial walls (septum) of the nasal cavity?

Answer 11

Bony part - ethmoid bone

Cartilaginous part

Question 12

What re the passages of the naval cavity called?

Answer 12

Sphenoidal recess
Superior meatus
Middle meatus
Inferior meatus

Question 13

Describe the ethmoidal bone.

Answer 13

It has a perpendicular plate in the centre with a cribriform plate at the top
Cribriform plate has lots of holes - for olfaction
Two Ethmoidal labyrinths (air cells) joined by the cribriform plate
The cribriform plate has the crista galli on top
Crista galli anchors falx cerebri
Infundibulum - a groove penetrating ethmoidal labyrinth and drains frontal sinus

Question 14

What are the openings inside the nasal cavity?

Answer 14

Cribriform plate - olfaction
Sphenopalatine foramen
Incisive foramen - nerve and artery exchange (to mouth)
Foramen cecum - nasal veins to superior sagittal sinus
(some individuals)

Question 15

Give an overview of the blood supply of the nasal cavity.

Answer 15

Facial artery (external carotid artery)
   - Brachial superior labial artery
Maxillary artery (external carotid artery)
   - Sphenopalatine artery
   - Greater palatine artery
Ophthalmic artery (internal carotid artery)
   - Anterior ethmoidal artery
   - Posterior ethmoidal artery

Question 16

What is the clinical significance to nasal blood supply?

Answer 16

An area of anastomoses:
- Kiesselbach’s plexus - (a.k.a. Little’s area)
So any damage can lead to epistaxis (nose bleed)

Question 17

Give an overview of the venous drainage of the nasal cavity

Answer 17

Drains to:

• Cavernous sinus
• Facial vein
• Pterygoid plexus

Question 18

Name some deformities of the nose and nasal cavity.

Answer 18

Nasal septum deviation
   - Congenital / acquired
   - Narrowing / obstruction
Nasal septum necrosis
   - Injury to nasal septum
   - Saddle nose deformity

Question 19

Give an overview of the innervation of the nasal cavity.

Answer 19

Special sensory innervation
- CN I: Olfactory Nerve
General sensory innervation to septum and lateral walls
- Ophthalmic (CN V1) and Maxillary (CN V2)
Posterior inferior of nasal cavity
- Maxillary nerve
- Nasopalatine nerve (septum) & branches greater
palatine nerve to lateral wall
Anterior superior of nasal cavity
- Ophthalmic nerve
- Branches of nasociliary nerve

Question 20

Give an overview of the innervation of the external nose.

Answer 20

Infraorbital nerve (CN V2)
External nasal nerve (CN V1)

Question 21

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

Answer 21

Pseudostratified columnar ciliated, with goblet cells

Question 22

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

Answer 22

Olfactory cells with olfactory receptors

Question 23

What are the paranasal sinuses?

Answer 23

Paired, mucous membrane lined out-pocketings of the nasal cavity, draining into the nasal cavity

Maxillary
Frontal
Sphenoid
Ethmoid

Question 24

What is the function of the paranasal sinuses?

Answer 24

Unknown
May contribute to conditioning of inspired air

Reduce weight of skull

Question 25

Describe the maxillary sinus.

Answer 25

``` Roof = floor of orbit Floor = alveolar part of maxilla Posteriorly = pterygopalatine & infratemporal fossae ``` Present at birth, enlarging from about 8yrs Opens into middle meatus

Question 26

Describe the frontal sinus.

Answer 26

Not present at birth Variable in size Related to anterior cranial fossa and the orbit Drains into the middle meatus through the frontonasal duct

Question 27

Describe the sphenoid sinus

Answer 27

Small at birth, enlarging after puberty Related to: - Pituitary fossa & middle cranial fossa - Cavernous sinus and inferior carotid artery - Posterior cranial fossa & pons - Roof of nasopharynx

Question 28

Describe the ethmoidal sinus.

Answer 28

Ethmoid air cells between orbit and nasal cavity ``` Anterior cells - Middle meatus via infundibulum Middle cells - Bulla - Directly into middle meatus Posterior cells - Superior meatus ```

Question 29

What is the clinical importance of the nasal cavities and the spread of infection?

Answer 29

Infection can spread to: - Anterior cranial fossa - Middle ear - Paranasal sinuses - Lacrimal apparatus & conjunctiva

Question 30

What is rhinitis?

Answer 30

``` Inflammation of the nasal mucosa - Leading to swelling & increased volume of secretion Causes include: - Infective (viral) - Allergic - Nasal polyps ```

Question 31

Tell me abut nasal polyps.

Answer 31

Prevalence ~2-4% Might be linked to chronic rhinosinusitis Grow close to the ostiomeatal complex of the nasopharynx Nasal obstruction - Snoring/obstructive sleep apnoea

Question 32

What is sinusitis?

Answer 32

Inflammation of the mucosal lining of the sinuses Acute: 7 - 30 days Sub-acute: 4-12 weeks Chronic: >90 days Infection - Viral with secondary bacterial infection - S pneumonia & H influenzae