Ear

Question 1

Describe the sensory innervation of the ear? What can ear pain be referred from?

Answer 1

Sensory innervation of the auricle/pinna, external auditory meatus and tympanic membrane is from 
multiple nerves (cranial & somatic)
Mandible, mandibular teeth, TMJ joint, Laryngopharynx, Larynx, Cardiac

Question 2

What is inflammation of the EAM called?

Answer 2

Otitis externa

Question 3

What is the sensory innervation of the EAM?

Answer 3

CN Vc and CN X

Question 4

How would you pull the ear (to straighten it) in an adult vs a child?

Answer 4

Adult - pull posterior and superiorly

Child - pull posterior and inferiorly

Question 5

What nerve might you see in the upper 1/3rd portion of the tympanic membrane?

Answer 5

Chorda Tympani - controls taste

Question 6

What is the sensory innervation of the resp mucosa of the tympanic membrane?

Answer 6

CN IX

Pain referred from pharynx

Question 7

What cranial nerve carries sensory from ALL portions of the Pharynx, Middle Ear, Auditory Tube & inner side of TM?

Answer 7

CN IX - glossopharyngeal n

Question 8

What are the names of the 3 middle ear ossicles?

Answer 8

Malleus, Incus, Stapes

Question 9

What two muscles in the middle ear control the vibrations of the ossicles? Mention their nerve supply.

Answer 9

Tensor Tympani - CN Vc

Stapedius - CN VII (facial)

Question 10

What happens in the ear if CN VII is damaged? (facial nerve palsy)

Answer 10

Hyperacusis

CN VII controls stapedius

Question 11

What are the 6 relations of the middle ear? (box)

Answer 11

Ant - carotid wall
Post - mastoid wall
Sup - tegmental 
Inf - jugular
lat - membranous
med - labarynthine

Question 12

What is mastoiditis?

Answer 12

Otitis Media infections in the middle ear can spread through the posterior wall into the mastoid air cells.
If left untreated can lead to a cerebral abscess or Dural venous thrombosis

Question 13

What clinical issues can occur as a result of blockage of the auditory/pharyngotympanic tube?

Answer 13

Otitis media:
produces pus
inf spread from nasopharynx to middle ear
perforation of TM can provide relief

Glue Ear:
inc mucus production
conductive hearing loss

Question 14

What ossicles do the 1st and 2nd pharyngeal arches form? mention nerve supply
What do the 1st cleft and 1st pouch form?

Answer 14

1st arch - Malleus and Incus (CN V)
2nd arch - Stapes (CN VII)
1st cleft - EAM
1st pouch - Middle ear and auditory tube

Question 15

What pharyngeal arch 1 defect can occur?

Answer 15

An additional external auditory meatus (small/non-functional) can develop
Auricular sinus can be quiescent or become infected (cysts)
OR Treacher Collins Syndrome

Question 16

How can test the choclear portion of CN VIII?

Answer 16

Rinne and Weber’s tests

Question 17

Describe the Weber test.

Answer 17

Tuning fork on forehead
Normal - no lateralisation
Conductive loss - loudest in affected ear
Sensorineural loss - loudest in normal ear

Question 18

Describe the Rinne test.

Answer 18

Tuning fork on mastoid process and then near ear canal

Normal: Air conduction > bone conduction (+ve test)