Lecture 26: Nasal Cavity & Paranasal Sinuses

Question 1

What forms the bony part of the nose?

Answer 1

Maxilla and nasal bones form bridge

Question 2

What is the rest of the nose made up of?

Answer 2

System of cartilage - septal, alar, lateral and hyaline

Question 3

What does the septal cartilage do?

Answer 3

Split nose into two halves

Question 4

What does alar cartilage do?

Answer 4

Forms lateral aspect of nostrils

Question 5

What is the shape of the ethmoid bone in the coronal plane and what are its projections?

Answer 5

M shaped

Has one midline projection (crista gali) and two lateral projections

Question 6

What happens if the nose breaks and causes fracture to the cribiform plate?

Answer 6

Due to close proximity to the brain and meninges there can be infection and bleeding introduced to these regions

Question 7

What is the relationship between the olfactory bulb and the crista gali?

Answer 7

Bulb sits lateral to the crista gali on each side and has little filaments that project through holes in the cribriform plate to reach nasal cavity

Question 8

What is rhinorrhea?

Answer 8

Leaking of the CSF from the subarachnoid space into the nose (may occur if the cribiform plate is broken)

Question 9

What forms the floor of the nasal cavity?

Answer 9

Maxilla

Question 10

What forms the posterior boundary of the nasal cavity?

Answer 10

Palatine bone

Question 11

What forms the septum of the nose?

Answer 11

Septal cartilage anteriorly and vomer posteriorly

Question 12

What is the posterior nare?

Answer 12

The posterior opening of the nasal cavity

Question 13

What are the features of the vestibule?

Answer 13

Lined with keratinised (thickened) skin and hair - skin provides protection and hair traps foreign particles

Question 14

What area is a nose bleed associated with?

Answer 14

Vascular mucosa

Question 15

What are the features of the mucous membrane?

Answer 15

Highly vascular and continues from nasal cavity to airways

Question 16

Why is it important that the mucous membrane is vascularised?

Answer 16

To warm up the air to get it closer to body temp - avoid cold air causing smooth muscle spasm

Question 17

What is the role of the mucous cells?

Answer 17

Humidify the air

Question 18

What area in the nasal cavity and throat is ciliated and what is the function of this?

Answer 18

Inferior 2/3 and airways - cilia actively beat from lower airways to nose to expel mucous

Question 19

What changes in the cilia of a smoker?

Answer 19

Not as active, mucous build up, difficulty breathing

Question 20

What part of the nasal cavity is the olfactory area?

Answer 20

Upper third

Question 21

What is the role of the conchae?

Answer 21

Produce turbulence in air as we breathe to allow it to remain in the nasal cavity longer to be heated and humidified

Question 22

What is under each concha and what opens here?

Answer 22

Meatus - openings for paranasal sinuses

Question 23

What paranasal sinus is more prone to infection and why?

Answer 23

The frontal, ethmoid and sphenoid sinuses are less prone to infection than the maxillary sinus because they sit above the nasal cavity and open downwards (bacteria has to work against gravity) and they also drain well. The maxillary sinus opens high on the medial wall and so doesn’t drain well in the upright position

Question 24

What encourages drainage of the maxillary sinus?

Answer 24

Patient lying in a downwards tilted position

Question 25

What can happen to the maxillary sinus when teeth are removed?

Answer 25

Fracture inferior part of maxillary sinus - pathway for infection

Question 26

What happens if there is compression of the mucous membrane?

Answer 26

Due to innervation there will be pain - pain referred to respective areas due to trigeminal nerve innervation

Question 27

What sinus cannot be seen in a radiographic sagittal plane?

Answer 27

Sphenoid

Question 28

Where do paranasal sinuses open?

Answer 28

Superior and middle meatuses

Question 29

Where does the frontal sinus open?

Answer 29

Middle meatus and the anterior end of the hiatus semilunaris

Question 30

Where does the sphenoid sinus open?

Answer 30

Sphenoethmoidal recess: back end of the top of the nasal cavity near the superior concha

Question 31

What else opens into the superior meatus?

Answer 31

Posterior ethmoidal sinuses

Question 32

What is the hiatus semilunaris?

Answer 32

Crescent shaped groove in the middle meatus, associated with bulla ethmoidalis (swelling). Important landmark because at the very anterior part of the hiatus there are openings for the frontal sinus and the anterior ethmoidal air cells and the posterior end of the hiatus forms an opening for the maxillary sinus

Question 33

What opens into the bulla ethmoidalis?

Answer 33

Middle ethmoidal air cells

Question 34

What is the nasolacrimal duct orifice?

Answer 34

Opening for nasolacrimal duct - drains from lacrimal gland to lacrimal sac - reason why nose runs when crying

Question 35

What is the blood supply to the quadrants of the nasal canal?

Answer 35

Posterior Quadrants: sphenopalatine artery (thick – if you get a bad nose break there will be high pressure bleeding)

Superior Quadrants: branches of the ophthalmic artery (gives of ethmoidal arteries)

Inferior Quadrants: supplied by branches of greater palatine artery (moves through opening in hard palate)

Anterior Quadrants:
Lateral: lateral nasal branches of facial arteryMedial: superior labial arteries

Question 36

What veins drain the nasal cavity?

Answer 36

Submucosal plexus drains via ophthalmic, sphenopalatine and facial veins

Question 37

What is the nerve supply to the anterior superior region of the nose?

Answer 37

Branches of the ophthalmic division (anterior ethmoidal nerves V1)

Question 38

What is the nerve supply to the posterior inferior region of the nose?

Answer 38

Branches of the maxillary division (branches of greater and lesser palatine nerves V2)