Anatomy & physiology of nose, nasal cavity, nasal septum

Question 1

In intra-uterine life, the nasal cavities are separated from what?

Answer 1

From the primitive buccal cavity

Question 2

What separates the primitive buccal cavity from the nasal cavities?

Answer 2

The bucconasal membrane

Question 3

What happens to the bucconasal membrane?

Answer 3

It breaks down

Question 4

When does the bucconasal membrane break down?

Answer 4

During the 6th week of intrauterine life

Question 5

What is the anatomy of external nose?

Answer 5

(A) Bony-cartilaginous skeleton, covered by (B) Soft Tissue

Question 6

What is the composition of the bony-cartilaginous part of external nose?

Answer 6

1) The Bony part:
- Forms the upper 1/3 of external nose
- Composed of the 2 nasal bones, which are:
* Connected together by the internasal suture
* Superiorly attached to the frontal bone
* Laterally attached to the frontal process of
maxilla

2) The Cartilaginous part:
- Forms the lower 2/3 of external nose
- Composed of 2 pairs of cartilages:-
* A Pair = upper lateral cartilages
* A Pair = lower lateral cartilages

Question 7

What is the composition of the soft tissue part of external nose?

Answer 7

1. Skin
2. Subcutaneous tissue
3. Muscles, all supplied by facial nerve

Question 8

What is function of the nasal septum?

Answer 8

Divides the nasal cavity into two separate cavities

Question 9

What are the openings of each nasal cavity?

Answer 9

Each nasal cavity has:

1. Nostril (anterior opening), communicating with the outside atmosphere.
2. Choana (posterior opening), communicating with the nasopharynx.

Question 10

What are the divisions of each nasal cavity?

Answer 10

1) Vestibule of the nose

2) Nasal cavity proper

Question 11

What is the vestibule of the nose lined by?

Answer 11

Skin carrying short stout hairs (vibrissae)

Question 12

What are the divisions of the nasal cavity proper?

Answer 12

1) Respiratory part:
- Occupies the lower 80% of the nasal cavity proper
- Lined by respiratory mucosa
- Function: Air conditioning

2) Olfactory part:
- Occupies the upper 20% of the nasal cavity proper
- Lined by olfactory mucosa
- Function: Smell

Question 13

What are the walls of the nasal cavity?

Answer 13

• Roof
• Floor
• Medial wall
• Lateral wall

Question 14

What composes the roof of the nasal cavity?

Answer 14

Cribriform (hortizontal) plate of ethmoid bone

Question 15

What composes the floor of the nasal cavity?

Answer 15

Hard palate

Question 16

What composes the medial wall of the nasal cavity?

Answer 16

Nasal septum

Question 17

What composes the lateral wall of the nasal cavity?

Answer 17

• Maxilla

- Ethmoid bones

Question 18

What is the nasal septum composed of?

Answer 18

Bony part and cartilaginous part

Question 19

What is the bony part of the nasal septum composed of?

Answer 19

1. Perpendicular plate of ethmoid bone

2. Vomer

Question 20

What is the cartilaginous part of the nasal septum composed of?

Answer 20

The nasal septal cartilage

Question 21

In which region are the three nasal turbinate bones located?

Answer 21

The lateral wall of nasal cavity

Question 22

Name the three nasal turbinates

Answer 22

1. Superior turbinate
2. Middle turbinate
3. Inferior turbinate

Question 23

Describe a nasal turbinate

Answer 23

A turbinate is a bony projection (concha) coverd by thick mucous membrane made of pseudostratified ciliated columnar epithelium

Question 24

What is a meatus?

Answer 24

Space underneath each turbinate bone

Question 25

Name the three meatuses

Answer 25

1. Superior meatus 2. Middle meatus 3. Inferior meatus

Question 26

What is the spheno-ethmoidal RECESS?

Answer 26

The space ABOVE the SUPERIOR turbinte bone

Question 27

What does the inferior meatus receive?

Answer 27

Opening of nasolacrimal duct

Question 28

What does the middle meatus receive?

Answer 28

- Opening of anterior ethmoid sinus - Opening of middle ethmoid sinus - Opening of maxillary sinus (= Receives openings of ALL sinuses EXCEPT opening of posterior ethmoid sinus and sphenoid sinus)

Question 29

What does the superior meatus receive?

Answer 29

Opening of posterior ethmoid sinus

Question 30

What does the spheno-ethmoidal recess receive?

Answer 30

Opening of sphenoid sinus

Question 31

What is the arterial supply of the nose?

Answer 31

A) ICA > Opthalmic artery: 1. Anterior ethmoidal artery 2. Posterior ethmoidal artery B) - ECA > Maxillary artery: 1. Sphenopalatine artery (artery of epistaxis) 2. Greater palatine artery 3. Other nasal branches > Facial artery: 1. Superior labial branch, septal branch

Question 32

Where is Little's area?

Answer 32

On the antero-inferior part of the nasal septal cartilage

Question 33

Where is Kisselbach's plexus?

Answer 33

At Little's area on the antero-inferior part of the nasal septal cartilage

Question 34

What is Kisselbach's plexus?

Answer 34

Anastomosis of arteries present at Little's area on the antero-inferior part of the nasal septal cartilage

Question 35

What are the arteries contributing to Kisselbach's plexus?

Answer 35

``` 1. Anterior ethmoidal artery inferior 2. Sphenopalatine artery (artery of epistaxis) 3. Greater palatine artery 4. Superior labial artery, septal branch ```

Question 36

What is the significance of Little's area?

Answer 36

It is the commonest site of anterior epistaxis

Question 37

Where is the commonest site of anterior epistaxis?

Answer 37

Little's area

Question 38

What is the significance of the venous drainage of the nose?

Answer 38

Significant role in INTRACRANIAL SPREAD of infection from the nasal cavity and the paranasal sinuses.

Question 39

What is the lymphatic drainage of the nose?

Answer 39

1. Sub-mandibular LN 2. Retro-pharyngeal LN And they both ultimately drain into Upper Deep Cervical LN

Question 40

What is the nerve supply of the nose?

Answer 40

1. Olfactory nerves (contribute to intracranial spread on infection) 2. Trigeminal nerve 3. Parasympathetic nerve supply 4. Sympathetic nerve supply

Question 41

Physiological function of the nose?

Answer 41

1. An airway for breathing 2. Air conditioning (filtration, humidification, warming) 3. Reflex functions, such as sneezing 4. Olfaction