Ear Flashcards

1
Q

What nerves carry general sensation from the ear?

A

Cervical spinal nerves C2-3
Vagus
Trigeminal (auricotemporal)
Glossopharyngeal (tympanic)

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2
Q

What makes up the external ear?

A

Pinna
External auditory meatus
Lateral surface of tympanic membrane

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3
Q

What is the role of the external ear?

A

Collect, transmit and focus sound waves onto tympanic membrane

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4
Q

What is a pinna haematoma also known as?

A

Cauliflower ear

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5
Q

What causes a pinna haematoma?

A

Blunt injury to the pinna

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6
Q

What is a pinna haematoma?

A

Accumulation of blood between cartilage and its overlying perichondrium

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7
Q

What is the risk of a pinna haematoma?

A

Subperichondrial haematoma deprives cartilage of its blood supply

Risk of necrosis

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8
Q

How is a pinna haematoma managed?

A

Drainage and compression to prevent re-accumulation of blood

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9
Q

What is the external acoustic meatus?

A

Connects outer ear to tympanic membrane

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10
Q

How long is the external acoustic meatus?

A

~2.5 cm in length

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11
Q

What lines the external acoustic meatus?

A

Keratinising stratified squamous epithelium

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12
Q

What forms the structure of the external acoustic meatus?

A

Outer 1/3 = cartilaginous

Inner 2/3 = bony

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13
Q

What is the shape of the external acoustic meatus?

A

Sigmoid

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14
Q

How is the external acoustic meatus protected?

A

Cartilage part is lined by hair, sebaceous and ceruminous glands

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15
Q

What are ceruminous glands?

A

Wax producing glands

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16
Q

What are common conditions affecting the external acoustic meatus?

A

Wax

Otitis externa

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17
Q

What is otitis externa?

A

Inflammation of the external acoustic meatus

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18
Q

What is otitis externa also known as?

A

Swimmer’s ear

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19
Q

What can cause otitis externa?

A

Water trapped in ear
Damage to skin in ear
Skin problems
Wax build up

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20
Q

What are the symptoms of otitis externa?

A
Itching/pain in ear canal
Watery discharge from ear canal 
Dry flaky skin around outside of ear and in canal 
Reduced hearing 
Discomfort when moving jaw
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21
Q

How is otitis externa managed?

A

Antibiotic + steroid ear drops

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22
Q

What are common abnormalities of the tympanic membrane?

A

Perforation

Bulging - due to otitis media

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23
Q

What is the middle ear?

A

Air filled cavity between tympanic membrane and inner ear containing ossicles

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24
Q

What is the role of the middle ear?

A

Amplify and relay vibrations from the tympanic membrane to the oval window tof the cochlea

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25
Q

What bones make up the ossicles?

A

Malleus
Incus
Stapes

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26
Q

What muscles are involved in the middle ear?

A

Tensor tympani

Stapedius

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27
Q

What is one of the most common causes of acquired hearing loss in young adults?

A

Otosclerosis

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28
Q

What is otosclerosis?

A

Condition where ossicles are fused at articulations due to abnormal bone growth

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29
Q

What bone is most commonly effected by otosclerosis?

A

Stapes

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30
Q

What type of hearing loss occurs in otosclerosis?

A

Conductive

31
Q

What is the role of the pharyngotympanic tube?

A

Equilibrate pressure of middle ear with atmospheric pressure

Ventilation of middle ear

Drainage of mucus from middle ear

32
Q

What is the pharyngotympanic tube also known as?

A

Eustachian tube

33
Q

What is the pressure in the middle ear?

A

Negative pressure - mucous membrane reabsorbs air I middle ear

34
Q

What is a cholesteatoma?

A

Sac of trapped epithelial cells that proliferate and erode

35
Q

What causes cholesteatoma?

A

ET dysfunction - negative pressures pull ‘pocket’ into middle ear

36
Q

What is the pathophysiology of cholesteatoma?

A

Retraction of area of tympanic membrane - forms a sac/pocket

Traps epithelial cells which proliferate and form cholesteatoma

37
Q

What are the symptoms of cholesteatoma?

A

Painless smelly otorrhea

+/- hearing loss

38
Q

What is the risk of a cholesteatoma?

A

Grows slowly and expands

Enzymatic bony destruction

39
Q

What is otitis media with effusion?

A

Build up of fluid and negative pressure in middle ear

40
Q

What is otitis media with effusion also known as?

A

Glue ear

41
Q

What can cause otitis media with effusion?

A

ET dysfunction

42
Q

What can be seen on otoscopy in otitis media with effusion?

A

Tympanic membrane retracted and straw coloured

43
Q

How is otitis media with effusion managed?

A

Most resolve within 2-3 months

Grommets

44
Q

What is acute otitis media?

A

Middle ear infection

45
Q

Who does acute otitis media effect more commonly?

A

Infants/children

46
Q

What are the symptoms of acute otitis media?

A

Otalgia
Fever

Red +/- bulging tympanic membrane

47
Q

Why are ear infections more common in infants?

A

Eustachian tube is more horizontal and shorter

48
Q

What are complications of acute otitis media?

A

Tympanic membrane perforation
Facial nerve involvement
Mastoiditis
Meningitis

49
Q

What is mastoiditis?

A

Infection of mastoid air cells

50
Q

What is the sign of mastoiditis?

A

Swollen red area behind ears

51
Q

How does mastoiditis occur?

A

Middle ear cavity communicates with mastoid air cells via mastoid antrum - route for infections to spread

52
Q

What is the inner ear?

A

Vestibular apparatus and cochlea

53
Q

What is the role of the cochlea?

A

Converts vibration into an electrical signal which is perceived as sound

54
Q

What is the role of the vestibular apparatus?

A

Maintaining our sense of position and balance

55
Q

What is the cochlea?

A

Fluid-filled tube with specialized hair cells (stereocilia) that generate action potentials when moved

56
Q

What cranial nerve is associated with the cochlea?

A

CN VIII - vestibulocochlear

57
Q

What type of hearing loss is associated with cochlea/CNVIII dysfunction?

A

Sensioneural

58
Q

How do we hear?

A

Auricle and external acoustic meatus focus sound waves towards tympanic membrane

Tympanic membrane vibrates

Ossicles vibrate and set up vibrations in cochlear fluid

Vibrations sensed by stereocilia in cochlear duct

Movement triggers CNVIII

Primary auditory cortex

59
Q

What is the vestibular apparatus?

A

Semicircular ducts, saccule and utricle - fluid filled tubes that generate action potentials to do with balance

60
Q

What cranial nerve is associated with the vestibular apparatus?

A

CNVIII

61
Q

What conditions can affect the inner ear?

A

BPPV
Meniere’s disease
Labrynthitis

62
Q

What is BPPV?

A

Benign paroxysmal positional vertigo

  • short bursts of vertigo
  • due to movements of head
  • little crystals in vestibular apparatus
63
Q

What is Meniere’s disease?

A

Progressive disease affecting vestibular apparatus and cochlear

64
Q

What is labyrinthitis?

A

Infection of inner ear

65
Q

What is the normal pattern in a Rinne’s test?

A

Air > bone

66
Q

What occurs in Rinne’s test with sensorineural hearing loss?

A

Air > bone

67
Q

What occurs in Rinne’s test with conductive hearing loss?

A

Bone > air

68
Q

What is the normal pattern in a Weber’s test?

A

Midline

69
Q

What occurs in Weber’s test with sensorineural hearing loss?

A

Lateralises to normal ear

70
Q

What occurs in Weber’s test with conductive hearing loss?

A

Lateralises to the affected ear

71
Q

What causes conductive hearing loss?

A

Pathology involving external or middle ear

Wax
Acute otitis media
Otitis media with effusion
Otosclerosis

72
Q

What causes sensorineural hearling loss?

A

Pathology involving inner ear or CN VIII

Presbyacusis 
Noise-related hearing loss
Meniere's disease
Ototoxic medications
Acoustic neuroma
73
Q

What is presbyacusis?

A

Age-related hearing loss