Lecture 9: Nasal Cavity

Question 1

What are the nasal regions?

Answer 1

1. nasal vesitubule
2. respiratory region
3. olfactory region

Question 2

External nose structures?

Answer 2

These cartilage plates are the ‘growth plates’ for the nose and damage in childhood can result in deformed growth in older age

Question 3

Bones of the medial wall

Answer 3

Septal cartilage is of clinical importance as damage may result in breakage of the septal arteries leading to a septal haematoma which if not drained can lead to loss of the nose.

Question 4

Floor of the nasal cavity?

Answer 4

Made up of the horizontal plate of the palatine bone and the palatine process of the maxilla. These both have nasal crests that articulate with the Vomer

Question 5

Bones that make up the roof of the nasal cavity?

Answer 5

• nasal bones
• nasal spine of the frontal bone
• Cribriform plate - ethmoid bone
• sphenoid bone

Question 6

The ethmoid bone is made of?

Answer 6

Made of three parts coming together to make a bony structure.

Consists of:

• crista galli
• cribriform plate (with perforations for olfactory nerves)
• perpendicular plate
• laterally the ethmoidal labyrinth, superior and middle turbinate (inferior comes from another structure)

Question 7

Lateral wall of the nasal cavity?

Answer 7

• Superior and middle concha (ethmoid bone)
• Inferior concha
• perpendicular plate of the palatine bone
• medial pterygoid plate of the sphenoid bone
• lacrimal bone
• frontal process of maxilla (+small part of frontal bone itself)
• nasal bone
• cartilage - lateral process of septal, major alar, minor alar

Question 8

What are the paranasal sinuses? where do they drain?

Answer 8

Above the superior turbinate is the sphenoidal sinus that drains in via the sphemoethmoidal recess.

Under the superior turbinate is the posterior ethmoidal sinus

Under the middle turbinate lies the middle ethmoidal sinus (via the ethmoid bulla), the anterior ethmoid sinus, frontal sinus and maxillary sinus

Under the inferior turbinate is the nasolacrimal duct where tears come out (runny noe when you cry)

Question 9

Answer 9

Question 10

Gateways into the nasal cavity?

Answer 10

1. naris
2. Incisive canal
3. foramen cecum
4. cribriform plate
5. sphenopalatine foramen
6. small foramina on the lateral wall

Question 11

Bloody supply? Area of risk for bleeding?

Answer 11

Septal branch of the anterior ethmoidal artery (from the opthalmic), septal branch of the nasal artery and the terminal part of greater palatine artery and also some extensions of the posterior ethmoidal artery may reach the anastamoses at the septum - risk of bleeding

Laterally the sphenopalatine artery comes through the sphenopalatine foramen and mainly contributes to the lateral wall - bleeding requires immdiate attention to stop

Question 12

venous drainage?

Answer 12

They drain into the facial vein, pterygoid plexus mostly (but also the cavernous sinus and also the nasal vein runs through the foramen cecum)

Question 13

Innervation of the nasal cavity? lymphatics?

Answer 13

General sensation comes from V1 and V2

PS = CN VII and S = T1

Lymphatics drain to the submandibular gland and then to the deep cervical llymph node.