Nose Anatomy

Question 1

What do you call the area between the root and apex of the nose?

Answer 1

Dorsum

Question 2

What is the significance of the ethmoid bone?

Answer 2

contributes to nasal cavities

Question 3

What are the roof, lateral wall and septum formed by?

Answer 3

Roof - cribriform plate and crista Galli Lateral - superior and middle conchae, ethmoidal air cells, orbital plate of the ethmoid and inferior conchae Septum - perpendicular plate of ethmoid bone and vomer

Question 4

Which level of le Fort fracture can disrupt the ethmoid bone?

Answer 4

2 and 3 as these fracture at the cribriform plate of the ethmoid

Question 5

What is the danger of le fort fractures 2 and 3?

Answer 5

danger of infection spreading from the nasal cavity and paranasal sinuses into the anterior cranial fossa

Question 6

What forms the lateral wall of the nasal cavity?

Answer 6

Superior and middle concha, inferior concha (one individual bone),, ethmoidal air cells and orbital plate of ethmoid bone. The maxilla and palatine bone also contribute along with the nasal bone

Question 7

What is the septum made from?

Answer 7

Perpendicular plate of ethmoid bone and vomer plus septal hyaline cartilage

Question 8

What is a feature of hyaline cartilage?

Answer 8

Avascular

Question 9

What is the type of mucosa at each of the 3 locations?

Answer 9

1. Keratinised stratified epithelium
2. respiratory epithelium
3. olfactory epithelium

Question 10

What are the features of keratinised stratified squamous epithelium?

Answer 10

It is found at the apex of the internal aspect of the nose and contains small hairs that filer foreign objects. it is considered to be a ‘skin-like’ mucosa.

Question 11

What are the features of respiratory epithelium?

Answer 11

Cilliated and produced mucous this is in order to trap and move foreign bodies to be swallowed and to humidify and warm air

Question 12

What are the features of olfactory epithelium?

Answer 12

Contain nerve fibres from the olfactory nerve which sense smell.

Question 13

What do you know about the olfactory nerve?

Answer 13

It is CN 1.

It is a special sensory nerve

It’s first neurons are in the olfactory mucosa (called receptor cells) and hang down through the cribiform plate. These detect smell. The signal then travels to the olfactory bulb (which is a ganglion containing the 2nd neurons and this is where synapses occur). The signal then continues down the optic tract to the temporal lobe.

Question 14

Are olfactpry receptor cells present on just the lateral wall of the nose?

Answer 14

No, they are present on both the medial and lateral walls

Question 15

What is the somatosensory supply to the nose?

Answer 15

The anterosuperior aspect is supplied by the opthalmic branch of the trigeminal nerve (CNV1)

The posteroinferior aspect is supplied by the maxillary division of the trigeminal nerve (CNV2)

present on both lateral wall and septum.

Question 16

What are the branches of the external and internal arteries that supply the nose?

Answer 16

External - facial and maxillary

Internal - opthalmic

Question 17

Which arteries give rise to the labelled arteries in the diagram?

Answer 17

Anterior and posterior ethmoidal - opthalmic

Sphenopalantine and greater palantine - maxillary

Lateral (or septal) - facial

Question 18

What is Kiesselbach’s area?

What is its clinical significance?

Answer 18

This is the site of anastamoses between the anterior and posterior ethmoidal, sphenopalantine, greater palantine and lateral arteries.

This is the most common site for epitaxis (nose bleeds)

Question 19

What are conchae and what are their functions?

Answer 19

There are 3 conchae (superior, middle and inferior) and can be called the turbinate bones. They are all covered in respiratory epithelium (so increase surface area for humidifying, warming and trapping bacteria) but also create turbulent air flow (which leads to better gas exchange).

Question 20

What are meatuses?

How many are there?

Answer 20

These are the spaces behind the conchae and are where the paranasal sinuses drain to.

3 + 1 sphenoethmoidal recess which sits posterior to the superior concha

Question 21

How would you ensure a nasogastric tube has made it to the stomach?

Answer 21

Taking an x-ray to below the diaphargm. The tube should stay midline until the level of the diaphragm, should not be coiled and the tip should be clearly visible. If measured the tip should be about 10cm from the GOJ.

Question 22

What are the paranasal sinuses?

Answer 22

These are air filled spaces within the bones surrounding the nasal cavity.

Question 23

How many paransal sinuses are present in the skull?

Answer 23

Ethmoid bone - many ethmoid air cells

Frontal bone - should have 2 (right and left separated by a septum)

Maxilla - 2

Sphenoid bone - 2

Question 24

What lines the paranasal sinuses?

Answer 24

Respiratory mucosa (cilliated and mucous secreting)

Question 25

What is the function of paranasal sinuses?

Answer 25

This is still debated but theories include:

• making the skull lighter as decrease the amount of dense bone in the skull
• Help with voice resonance
• Filters foreign bodies

Question 26

Where does mucous secreted from the paranasal sinuses drain into?

Answer 26

Drains through the ostia in the lateral walls of the nasal cavities. These then drain into meatuses (spaces below the concha)

Question 27

Where does each parasinuse drain to specifcally?

Answer 27

Superior meatus - Ethoidal air cells

Middle Meatus - ethmoidal air cells, frontal sinus, maxillary meatus

Sphenoethmoidal recess - sphenoid sinuses

Question 28

What drains to the inferior meatus?

Answer 28

The nasolacrimal duct - this is why when you cry you get a runny nose!

Question 29

What is sinusitis?

Answer 29

This is the inflammation of the mucosa of the paranasal sinuses cause by infection, allergy or autoimmune issues.

Question 30

Which nerve senses pain from sinusitis?

Answer 30

CNV1 and CNV2

(can present as referred pain to the tooth as shared common nerve supply)

Question 31

Why are the maxillary sinuses predisposed to sinusitis?

Answer 31

This is because in order for the sinus to drain the mucous must move against gravity as the ostia is located superiorly to the sinus (at the middle meatus).

It is also in close proximity to the teeth so an abscess that moves through the bone (causing a fistula) can cause infection.

Question 32

Why is there referred pain to the teeth in sinusitis?

Answer 32

As there is a common sensory supply through the trigeminal nerve.