The Nasal Cavity 2

Question 1

what forms a portion of the roof of the nasal cavity?

Answer 1

The cribriform plate (part of the ethmoid bone) It forms a portion of the roof of the nasal cavity

Question 2

what openings does the cribriform plate (ethmoid bone) contain? what travels through?

Answer 2

very small perforations, allowing fibres of the OLFACTORY (CN I - smell) nerve to enter and exit

Question 3

where is the sphenopalatine foramen located?

Answer 3

At the level of the superior meatus

Question 4

what is the function of the sphenopalatine foramen?

Answer 4

This hole allows communication between the nasal cavity and the pterygopalatine fossa

Question 5

what passes through the sphenopalatine foramen?

Answer 5

The sphenopalatine artery,

nasopalatine and superior nasal nerves

Question 6

what is the incisive canal?

Answer 6

a pathway between the nasal cavity and the incisive fossa of the oral cavity

Question 7

what travels through the incisive canal?

Answer 7

nasopalatine nerve and greater palatine artery

Question 8

how is the blood supply like in the nose? why?

Answer 8

very rich vascular supply – allows it to effectively change humidity and temperature of inspired air

Question 9

where does the nose receive blood supply from?

Answer 9

both the internal and external carotid arteries

Question 10

what are branches of the internal carotid artery which supplies the nose?

Answer 10

Anterior ethmoidal artery

Posterior ethmoidal artery

Question 11

what are the ethmoidal arteries branches of?

Answer 11

the opthalmic artery

Question 12

how do the ethmoidal arteries travel through the skull?

Answer 12

They descend into the nasal cavity through the cribriform plate

Question 13

what are the branches of the external carotid artery which supply the nose?

Answer 13

Sphenopalatine artery
Greater palatine artery
Superior labial artery
Lateral nasal arteries

Question 14

In addition to the rich blood supply, what happens to the arteries supplying the nose?

Answer 14

they anastamoses with each other

Question 15

where is anastomoses of the arteries most prevalent?

Answer 15

in the anterior portion of the nose

Question 16

where do the veins of the nose travel and drain to?

Answer 16

The veins of the nose tend to follow the arteries

drain into the pterygoid plexus, facial vein or cavernous sinus

Question 17

what can nasal veins join with in some individuals? resulting in?

Answer 17

a few nasal veins join with the sagittal sinus (a dural venous sinus)
represents a potential pathway by which infection can spread from the nose into the cranial cavity

Question 18

what is epistaxis?

Answer 18

nosebleed

Question 19

where is epistaxis most common?

Answer 19

anterior 1/3rd of nasal cavity - Kisselbach’s area

Question 20

causes of epistaxis?

Answer 20

local e.g. trauma

systemic e.g. hypertension

Question 21

how can the innervation of the nose be divided?

Answer 21

into special and general innervation

Question 22

what is special sensory innervation of the nose?

Answer 22

the ability of the nose to smell

carried out by the olfactory nerves (CN I)

Question 23

what is the olfactory bulb and where is it found?

Answer 23

part of the brain, lies on the superior surface of the cribriform plate, above the nasal cavity

Question 24

where do branches of the olfactory nerve (special sensation: smell) travel?

Answer 24

run through the cribriform plate (ethmoid bone)

Question 25

where does general sensory innervation to the septum (middle) and lateral walls from?

Answer 25

the nasopalatine nerve and the nasociliary nerve

Question 26

what are the nasociliary and nasopalatine nerves a branches of?

Answer 26

nasociliary = ophthalmic nerve (V1 - higher up)
nasopalatine = maxillary nerve (V2)

Question 27

what supplies innervation to the external skin of the nose?

Answer 27

the trigeminal nerve

Question 28

causes of fracture of the cribriform plate?

Answer 28

can occur as a result of nose trauma

either fractured directly by the trauma, or by fragments of the ethmoid bone

Question 29

what can a fractured cribriform plate result in?

Answer 29

A fractured cribriform plate can penetrate the meningeal linings of the brain, causing leakage of cerebro-spinal fluid

Question 30

what happens if there is leakage of CSF?

Answer 30

Exposing the brain to the outside environment, increases risks of meningitis, encephalitis and brain abscesses

Question 31

what else can be irreversibly damaged in a cribriform plate fracture?

Answer 31

The olfactory bulb lies on the cribriform plate and can be damaged irreversibly by the fracture

Question 32

how will patients present if the olfactory bulb is damaged?

Answer 32

anosmia (loss of smell)