Week 9

Question 1

Where does the nasal cavity start

Answer 1

from the nostrils (the anterior nares) - air goes through here and passes back through the nasal cavity to the back edge of the nasal septum where the nasal cavity ends

Question 2

What is the posterior nares

Answer 2

where air comes out from the nasal cavity into the nasopharynx (sometimes called choanae)

Question 3

What are the conchae

Answer 3

• There are large folds of bone covered by mucous membranes that project into the nasal cavity from the lateral wall and these are called the conchae

Question 4

What is the inferior conchae

Answer 4

The inferior conchae is the largest of them and it is a bone in its own right

Question 5

What is the superior conchae

Answer 5

○ The superior and middle conchae are considered part of the ethmoid bone

Question 6

What is the nasal cavity lined by

Answer 6

• The nasal cavity is lined by respiratory epithelium - pseudostratified columnar epithelium with cilia and goblet cells interspersed between

Question 7

Where is the special epithelium

Answer 7

• At the top of the nasal cavity in the lateral wall and the roof and onto the septum, there is special olfactory epithelium for the sense of smell

Question 8

What is the blood supply of the nasal cavity like

Answer 8

• The mucosa of the nasal cavity has a rich plexus of blood vessels

Question 9

What is the function of the blood supply of the nasal cavity

Answer 9

to provide warmth to the air as it comes in and goblet cells produce mucus to collect any dust breathed in to prevent it going into the longs and the cilia waft the mucous back the way where it is swallowed

Question 10

Where does the air pass

Answer 10

• The air passes in the passageways below the conchae called the meatuses and they are named after the conchae above

Question 11

What is the area at the top between sphenoid and ethmoid bone called

Answer 11

• The area at the top is not a meatus and since the ethmoid bone forms the roof and the sphenoid bone sits behind, it is called the spheno-ethmoidal recess

Question 12

What is the vomer

Answer 12

is a part of the septum too

Question 13

Where can the nasolacrimal duct be seen

Answer 13

○ The bony canal opens into the inferior meatus of the nasal cavity about a third of the way along where the conchae is at its highest point

Question 14

What is the function of the nasolacrimal duct

Answer 14

○ It drains tears from the lacrimal sac of the eye into the nasal cavity.

Question 15

What does the nasolacrimal duct run through

Answer 15

○ The duct runs through a bony canal within the lateral wall of the nasal cavity

Question 16

What is hiatus semilunaris

Answer 16

• Hiatus semilunaris - it is a curved recess which is a crescent moon shape in the lateral wall of the middle meatus

Question 17

What is seen in hiatus semilunaris

Answer 17

frontal sinus opening - upper end

maxillary sinus opening - lower end

Question 18

When are the sinuses often infected

Answer 18

if there is a bad respiratory tract infection and it may spread to the frontal sinus giving a feeling of headaches and if the frontal sinuses are infected then it is likely infected material will pass into the maxillary sinus as it will trace down the hiatus and drop into the maxillary sinus

Question 19

What is the ethmoidal bulla

Answer 19

• In the area near the concavity of hiatus semi lunaris is the ethmoidal bulla which is a bulging piece of bone covered by mucous membranes and in this area there are lots of little holes called ethmoidal air cells (ethmoidal sinuses) and they have little ducts which open t various points on the in the vicinity of the bula or even on the other side of the middle conchae

Question 20

What can be seen inside the sphenoid bone

Answer 20

nside the sphenoid bone we can see the pituitary fossa where the pituitary gland

Question 21

What is below the sella tursica

Answer 21

there is the sphenoidal sinuses and they communicate with the nasal cavity via the spheno-ethmoidal recess

Question 22

What is the function of the sinuses

Answer 22

The sinuses may help warm air, lighten the skull or give strength to it

Question 23

What is the shape of the maxillary sinus

Answer 23

shaped like a 3 sided pyramid lying on its side and the base is the medial side next to the nasal cavity and hard palate
• One of the corners of the ‘pyramid’ lies close to the teeth
• The ‘apex’ is the corner which extends into the zygomatic process of the maxilla

Question 24

Why is it difficult for the maxillary sinus to drain

Answer 24

• It is difficult for the sinus to drain as the opening is high up on the medial side so if someone gets infective material gathering in the sinus then it may require intervention via antibiotics or even drainage

Question 25

What runs in the roof of the maxillary sinus

Answer 25

the infra orbital nerve which raises a bony ridge above it. The nerve starts off in foramen rotundum, going through the pterygopalatine fossa and then the maxillary nerve comes out into the orbit and then it changes its name to the infra orbital nerve and sinks into the floor of the orbit/roof of the maxillary sinus

Question 26

When can the infra orbital nerve be injured

Answer 26

if someone gets hit in the eye and the sudden impact can raise the pressure in the orbit, breaking the orbital floor and the orbital contents fall into the maxillary sinus and the infraorbital nerve may get displaced causing numbness, it requires surgical intervention

Question 27

What is a malignancy of the sinus

Answer 27

Can develop a carcinoma where the tumour is made of stratified squamous cells but the lining of the sinus is respiratory epithelium. Half of cases present as pain of the face as the tumour interferes with the infra orbital nerve or branches given to upper teeth

Other half of px present with tumour passing through floor of maxillary sinus and appearing in the gum area

Question 28

What does an oro-antral communication

Answer 28

may result in patient having fluid gathering in the maxillary sinus and the fluid comes out of the nose

Question 29

What is an oroantral fistula

Answer 29

when communication is not detected and the opening epithelium joins the epithelium of the oral cavity so the fistula is an epithelial lined channel

Question 30

What is the sphenopalatine foramen

Answer 30

this is the route the nasopalatine nerve takes when it goes into the nasal cavity to get to the septum and it goes down the septum to get to the palate where it enters via the incisive fossa

Question 31

Where is the anterior superior alveolar nerve found

Answer 31

• Anterior superior alveolar nerve is found in the lateral wall inside the bone but not raising a ridge, it has an S shaped course

Question 32

What can be seen at the back of the maxillary sinus

Answer 32

• At the back fairly low down you can see the posterior superior alveolar nerve which is a direct branch of the maxillary nerve and it is in the bone of the maxilla, close to the lining of the sinus

Question 33

What does the infra orbital nerve supply

Answer 33

supplies the skin of the face and it comes through the infra orbital foramen to supply the skin of the front part of the cheeks, the side of the nose (palpable part), the lower eyelid, the upper lip as well as innervating the mucosa inside the lip and gums anterior to the incisor teeth region

Question 34

When does the name of the maxillary nerve change to infra orbital

Answer 34

○ The maxillary nerve changes its name to the infra orbital nerve as soon as it runs into the orbit through the inferior orbital fissure

Question 35

Where is the anatomical location of the infra orbital nerve

Answer 35

○ The infraorbital nerve is tucked below the projecting inferior orbital margins and it is deep to muscles like levator anguli oris which has high attachments to the bone just below it

Question 36

What is the greater palatine artery a branch of

Answer 36

the maxillary artery