The Outer Ear

Question 1

What is the function of the outer ear?

Answer 1

to collect, resonate and localize sound as well as provide protection

Question 2

What frequencies does the outer ear resonate?

Answer 2

2000Hz - 7000Hz

Question 3

What is the resonant frequency of the EAM?

Answer 3

~2700 Hz

Question 4

The pinna forms at the same time as the _________ during embryological development

Answer 4

kidneys

Question 5

At what age does the pinna reach adult size?

Answer 5

~8 years old

Question 6

What is anotia?

Answer 6

an absent pinna

Question 7

what is microtia?

Answer 7

a very small pinna

Question 8

what is macrotia?

Answer 8

a very large pinna

Question 9

what is meltier?

Answer 9

displacement of the pinna

Question 10

What is the name of the surgery for pinning back ears?

Answer 10

otoplasty

Question 11

What are the two main components of the outer ear?

Answer 11

1) pinna

2) EAM

Question 12

Describe the outer 1/3 of the EAM

Answer 12

skin-covered cartilage

has sebaceous glands and follicles

Question 13

Describe the inner 2/3 of the EAM

Answer 13

skin-covered bone with no follicles or glands

Question 14

What is the name of the place where the outer and inner portions of the EAM meet

Answer 14

the osseocartilaginous junction

Question 15

Where your osseocartilaginous junction is, is often where your __________ joint is located

Answer 15

temperomandibular joint

Question 16

T or F the condyle sits bellow the OC junction at rest

Answer 16

True

Question 17

If the condyle presses into the OC junction, where is the pain often felt?

Answer 17

referred pain felt in the ear

Question 18

What determines the colour of your ear wax?

Answer 18

it is genetically based - based on your melanin

Question 19

Earwax grows in an _______ fashion

Answer 19

outward

Question 20

Cleaning your ears ________ the production of ear wax

Answer 20

increases

Question 21

What is atresia of the ear canal?

Answer 21

full closure of the ear canal

Question 22

What is stenosis of the ear canal?

Answer 22

narrowing or collapsing of the EAM

Question 23

Stenosis of the EAM is especially common in what population?

Answer 23

the elderly

Question 24

What is external otitis?

Answer 24

infeciton in the skin lining of the outer ear, AKA swimmers ear

Question 25

Does stenosis usually involve real world hearing loss?

Answer 25

no

Question 26

What are the 5 main components of the middle ear?

Answer 26

1) tympanic membrane 2) ossicles 3) middle ear space 4) Eustachian tube 5) Middle ear muscles

Question 27

Describe the structure of the tympanic membrane (TM)

Answer 27

- concave, disk like structure - area is 63-90 mm2 - width is 0.7mm - very rich in blood supply

Question 28

What are the three layers of the TM

Answer 28

- epidermal - fibrous - mucous

Question 29

The tympanic membrane is held in position by what structure?

Answer 29

the tympanic annulus

Question 30

Movement of the TM as little as __________________ can stimulate hearing

Answer 30

one billionth of a cm

Question 31

T or F a healthy TM is translucent

Answer 31

true

Question 32

What is it called when there is a hole in the tM

Answer 32

perforation

Question 33

How does scar tissue affect the TM?

Answer 33

it makes it more flaccid

Question 34

What is myringitis?

Answer 34

inflammation of the TM

Question 35

What is a tympanoplasty?

Answer 35

patching of a perforation in the TM

Question 36

What is the function of the ossicles?

Answer 36

they conduct TM vibration to the inner ear, and 'amplify' sound

Question 37

T or F: the malleus moves on its own and the incus and stapes move as one

Answer 37

F - the malleus and incus move as one, the stapes moves on its own

Question 38

What do we call it when the ossicles have been displaced from each other?

Answer 38

disarticulation

Question 39

What is otosclerosis?

Answer 39

starts when spongy bone forms over the stapes, and then it hardens and the footplate becomes fixed, causes conductive hearing loss

Question 40

Please describe the middle ear

Answer 40

air filled (2cm3) and has a mucous membrane lining

Question 41

The middle ear is connected to the nasopharynx via the _________

Answer 41

eustachian tube (ET)

Question 42

Where is the ET located?

Answer 42

it sits above the tonsils

Question 43

The ET is ______ at rest

Answer 43

closed

Question 44

what muscle is responsible for opening the ET?

Answer 44

the tensor veil palatini

Question 45

How often does the ET open during waking?

Answer 45

once/min

Question 46

How often does the Et open during sleep?

Answer 46

once/ 5 min

Question 47

The ET opens during ...

Answer 47

yawning, sneezing, swallowing or excessive nasal pressure

Question 48

Explain the differences in ET structure between adults and children?

Answer 48

- In adults the ET sits at a 30 degree angle, in children it is more horizontal, ~10 degrees - Children still have adenoids that can block the flow of fluid - Children are prone to ET dysfunction

Question 49

____% of the time, fluid in the middle ear of children is not used by infection

Answer 49

50%

Question 50

Air pressure of the middle ear must ______ the air pressure of the EAM

Answer 50

match

Question 51

What is the only natural way to maintain pressure equalization?

Answer 51

the eustachian tube

Question 52

When does the ET lock shut?

Answer 52

at extreme pressures

Question 53

What happens when the ET locks shut?

Answer 53

- great pain occurs - at risk for TM rupture - at risk for middle ear effusion

Question 54

What is meant by a patulous ET

Answer 54

the ET remains open

Question 55

What two groups of people are prone to patulous ET

Answer 55

- body builders (from clenching) | - people with bulimia

Question 56

______% of children have had otitis media by age 3, and _____% by age 5

Answer 56

30% | 75%

Question 57

25-50% of the time, otitis media is _______, meaning it doesn't have any noticeable symptoms

Answer 57

'silent'

Question 58

List as many risk factors as you can for otitis media (OM)

Answer 58

- age 18mos to 3years - bottle feeding - attendance in group day care - exposure to tobacco smoke - cranio-facial involvement - family history - premature birth - season

Question 59

T or F: the reason the risk for OM is higher when the infant is bottle fed is because they are lacking nutrients from the breast milk

Answer 59

no it is more likely the position of the baby during the feeding

Question 60

List the 3 categories of OM

Answer 60

- serous OM - acute OM - chronic OM

Question 61

Describe serous OM

Answer 61

air in the middle ear space is replaced by any type of fluid other than true pus

Question 62

What can cause serous OM?

Answer 62

- ET dysfunction - Mucous secretions blown through the ET - Allergies, upper RT infections, second hand smoke

Question 63

Describe acute OM

Answer 63

the middle ear is filled with bacteria or there is a viral infection -characterized by a rapid onset, fever, pain, irritability, disruption in sleeping or eating patterns

Question 64

Describe chronic OM

Answer 64

any fluid remains for an extended period of time (>8 weeks)

Question 65

List the possible treatments of OM

Answer 65

- wait and see - antibiotics - nasal spray - myringotomy with/without tubes - non-medical

Question 66

When a child has OM, when is waiting and seeing the right treatment?

Answer 66

children with no speech & language delays can be observed with 3 months with no detriments -children with persistent effusion or speech and language delays should be referred

Question 67

When should antibiotics be used to treat OM? Are they always effective

Answer 67

antibiotics should be used when there is an actual infection | -antibiotic therapy is minimally effective

Question 68

What is the function of the middle ear?

Answer 68

- carries vibration from the outer to inner ear | - overcomes loss of sound energy when sound passes from air to fluid

Question 69

When sound travels from air to water how much of sound energy is reflected? give answer in percent and dB

Answer 69

99.9% | 30dB

Question 70

What are the three ways the middle ear amplifier matches the energy loss from air-fluid

Answer 70

1. leverage action of ossicles 2. vibrating area of TM is 17x that of oval window 3. curved shape of TM focuses movement on the malleus

Question 71

The middle ear amplifier results in a pressure increase _________ at the oval window. This is a _____ dB increase

Answer 71

23 | 30dB

Question 72

What are cholesteatomas

Answer 72

benign mass growing in middle ear space due to chronic build up of non-infection based fluid

Question 73

What is petrositis?

Answer 73

infection of the mastoid air cells medial to the inner ear

Question 74

T or F: skull fractures can lead to middle ear problems

Answer 74

True

Question 75

What are the two muscles of the middle ear

Answer 75

- stapedius | - tensor tympani

Question 76

The middle ear muscles can reduce intensity by as much as _____ dB

Answer 76

15 dB