Mastoid air cells, muscles, Auditory Tube, clinical

Question 1

what is the auditory tube also known as?

Answer 1

eustachian tube

Question 2

what is the auditory tube?

Answer 2

a cartilaginous and bony tube that connects the middle ear to the nasopharynx

Question 3

function of the auditory tube?

Answer 3

It acts to equalise the pressure of the middle ear to that of the external auditory meatus

Question 4

where does the auditory tube extend?

Answer 4

It extends from the anterior wall of the middle ear, in anterior, medioinferior direction

Question 5

where does the auditory tube open onto?

Answer 5

the lateral wall of the nasopharynx

Question 6

In joining the two structures (auditory tube and lateral wall of nasopharynx), what does the auditory tube provide a pathway for?

Answer 6

In joining the two structures, it is a pathway by which an upper respiratory infection can spread into the middle ear

Question 7

where are mastoid air cells located?

Answer 7

posterior to epitympanic recess

Question 8

what are mastoid air cells?

Answer 8

a collection of air-filled spaces in the mastoid process of the temporal bone

Question 9

what are the air cells are contained within a cavity called?

Answer 9

the mastoid antrum

Question 10

how does the mastoid antrum communicates with the middle ear?

Answer 10

via the aditus to mastoid antrum

Question 11

what do the mastoid air cells act as?

Answer 11

a ‘buffer system‘ of air – releasing air into the tympanic cavity when the pressure is too low

Question 12

what is middle ear infection?

Answer 12

otitis media

Question 13

where can middle ear infections spread to?

Answer 13

mastoid air cells

Question 14

what are mastoid air cells suitable for? (think otitis media)

Answer 14

due to their porous nature, they are a suitable site for pathogenic replication

Question 15

what can be infected in otitis media?

Answer 15

the mastoid process itself

Question 16

where can infection spread to if the mastoid process is infected? causing?

Answer 16

middle cranial fossa and into the brain, causing meningitis

Question 17

if mastoiditis is suspected, what must you do?

Answer 17

the pus must be drained from the air cells

Question 18

when draining pus from the air cells in mastoiditis, what must one be cautious of?

Answer 18

care must be taken not to damage the nearby facial nerve

Question 19

how many muscles are there in the middle ear? function?

Answer 19

There are two muscles which serve a protective function in the middle ear

Question 20

what are the 2 protective muscles of the middle ear?

Answer 20

the tensor tympani and stapedius

Question 21

how do the tensor tympani and stapedius act in the middle ear?

Answer 21

They contract in response to loud noise, inhibiting the vibrations of the malleus, incus and stapes, and reducing the transmission of sound to the inner ear

Question 22

what are the actions of tensor tympani and stapedius called?

Answer 22

acoustic reflex

Question 23

where does the tensor tympani originate from? attach?

Answer 23

the auditory tube and attaches to the handle of malleus, pulling it medially when contracting

Question 24

what is the tensor tympani innervated by?

Answer 24

a branch of the mandibular nerve

Question 25

where does the stapedius muscle attach to?

Answer 25

the stapes

Question 26

what is the stapedius muscle innervated by?

Answer 26

the facial nerve

Question 27

what is glue ear?

Answer 27

Otitis media with effusion

Question 28

how does glue ear arise?

Answer 28

It arises from persistent dysfunction of the auditory tube.

Question 29

what will happen if the auditory tube is unable to equalise middle ear pressure?

Answer 29

a negative pressure develops inside the middle ear

Question 30

what causes auditory tube to not be able to equalise middle ear pressure?

Answer 30

due to blockage, inflammation, genetic mutation

Question 31

what does the negative pressure within middle ear from auditory tube unable to equalise middle ear pressure cause?

Answer 31

This negative pressure draws out a transudate from the mucosa of the middle ear, creating an environment suitable for pathogens to replicate and cause infection.

Question 32

Upon inspection of a patient with otitis media with effusion, how will the eardrum appear?

Answer 32

the eardrum will appear inverted, with fluid visible inside the ear