Week 1.7 - Anatomy and Physiology of the Nose

Question 1

What is the passage of air to the lungs?

Answer 1

nasal passage - nasal pharynx - oropharynx - larynx - lungs

Question 2

What are the functions of the nose?

Answer 2

• humidifies and warms air
• immune
• olfactory
• taste sensation

Question 3

Where are olfactory receptors found?

Answer 3

roof of nasal cavity. bind odour molecules, connect to olfactory nerve passing through cribriform plates to the olfactory bulb, which goes to the olfactory tract to the olfactory cortex

Question 4

What is choanal atresia?

Answer 4

failed recanalisation of the nasal fossa during foetal development. neonate cant breathe as nasal airway is blocked.

Question 5

What is the immune role of the nose?

Answer 5

• produces mucus which can neutralise organisms and has IgE and IgA. smoking reduces no. of cilia and thus viscocity of mucus

Question 6

What is the speech role of the nose?

Answer 6

nasal airway modifies speech resonance. paranasal sinuses also. blocked nose ends in bunged sounding voice.

Question 7

What is the structure of the nose?

Answer 7

vestibule, resp.region, olfactory region superior, auditory tube opening and nasopharynx posterior

Question 8

What are paranasal sinuses and their role? (6)

Answer 8

air filled cavities within nasal cavity.
- reduce skull weight,
- physical barrier for injury
- vocal resonance,
- humidification
- insulation
- immune barrier

Question 9

What is the structure of the external nose?

Answer 9

• nasion is junction of frontal and nasal bones
• labella - bony prominence above nasion
• rhinion - is junction between nasal bones and cartilage
• dorsum - base to tip
• columella - septum

Question 10

What is the nasal skeleton made up of?

Answer 10

bone and cartilage parts
- nasal bones
- paired upper and lower lateral cartilages and septal cartilage

Question 11

how do you deal with a nasal bone fracture?

Answer 11

mend within 1-2 weeks after swelling has reduced. can be permanent if heals without fix.

Question 12

What should we be aware of following a nasal trauma?

Answer 12

septal haematoma. may lead to saddle nose deformity - perforation of cartilage due to inadequate perfusion

Question 13

What are causes of saddle nose deformity?

Answer 13

• untreated septal haematoma
• cocaine use
• vasculitis
• iatrogenic

Question 14

What is the vasculature of the external nose?

Answer 14

• supratrochlear and dorsal nasal arteries from opthalmic artery
• infraorbital artery from maxillary artery
• septal and ala cartilage from angular artery and lateral nasal artery - external carotid
• venous drainage is facial vein

Question 15

What is the danger triangle and what is a risk?

Answer 15

highly anastamotic venous system which may allow infection to spread, causing cavernous sinus thrombosis. life and sight threatening.

Question 16

What are the nasal aerodynamics?

Answer 16

air flow at vestibule is laminar. as passage narrows, flow becomes turbulent. this allows prolonged contact with mucosa - for warming, humidification and trapping of particles

Question 17

What veins are within the danger triangle?

Answer 17

• superior and inferior opthalmic veins
• facial vein
• supraorbital vein
• maxillary vein

Question 18

What are signs of cavernous sinus thrombosis?

Answer 18

• proptosis
• chemosis
• cranial nerve palsies which run through cavernous sinus
• papilloedema with retinal haemorrhages
• decreased visual acuity and blindness
• fever, tachycardia, sepsis, headache with neck stiffness

Question 19

What is the innervation of the external nose?

Answer 19

• motor innervation is facial nerve Cr.N.Vii
• sensory from V1 infratrochlear and extra nasal nerves
• also V2 infraorbital nerve