Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

S3 AHNNAS > Anatomy Of The Ear > Flashcards

Anatomy Of The Ear Flashcards

1
Q

List some different symptoms of ear disease

A 
Otalgia
Discharge 
Hearing loss (conductive/ sensorineural)
Tinnitus
Vertigo facial nerve palsy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What makes up the external ear? What is it’s function?

A

Pinnacle / auricle
External auditory meatus
Tympanic membrane lateral surface

Skin lined

Collects, funnels, transmits and focuses sound waves on the tympanic membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What makes up the middle ear? What is it’s function?

A

Ossicles (stapes, malleus, incus) connected via synovial joints - amplify and relay vibrations from the TM to the oval window of the cochlea (vibrations -> waves fluid medium

Pharyngotympanic tube connects to oropharynx - allows equilibrium of pressure

Lined with respiratory epithelium

Air filled cavity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What makes up the inner ear? What is it’s function?

A

Cochlea
Semicircular canals

Fluid filled

Cochlea converts fluid movement (generated by footplate of stapes) causes movement of special sensory cells (stereocilia) into action potentials (CN8) perceived as sound.

Vestibular apparatus converts fluid move,not (generated by position and rotation of head) into action potentials (CN8) perceived as position sense and balance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Which nerves may present as pain in outer/ middle/ inner ear from referred pain from other places?

A

Many nerves carry general sensation from the ear

Branch of vagus Nerve 10

  • external
  • pharynx
  • larynx

Branch glossopharyngeal nerve 9

  • middle ear
  • posterior tongue
  • pharynx
  • tonsils

Nervus intermedius 7
- External ear

Lesser occipital nerve 2,3

  • superior pinna
  • supra- auricular scalp
  • posterolateral scalp

Great auricular Nerve 2,3

  • pinna
  • angle of jaw
  • lateral neck
  • skin over parotid G and mastoid process

Auriculotemporal 5

  • external ear
  • temporal scalp
  • pre- auricular area and tragus
  • temporomandibular joint

CN 8
Special sensory, hearing and balance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Otalgia with normal ear examination should make you suspect an alternative site of pathology. What other sites could it be?

A

Non-otological sites:

TMJ dysfunction CNVc

Diseases of oropharynx CN 9

Disease of larynx and pharynx

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are some pinna/ auricular abnormalities?

A

Ramsey- hunt syndrome - shingles of facial N, facial palsy + painful, red vesicular rash (varicella zosta)

Perichondritis - inflammation of cartilage e.g. infected piercing

Pinna haematoma - accumulation blood between cartilage and perichondrium, blunt injury, strips perichondrium (supplies underlying cartilage). Untreated -> fibrosis, asymmetrical cartilage development -> cauliflower ear (subperichondrial haematoma, deprives cartilage of blood supply + pressure necrosis of tissue) ✅cotton roll pushes perichondrium against cartilage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the external acoustic meatus?

A

2.5 cm

Lined with keratinising, stratified squamous epithelium - self cleaning, desquamation and skin migration laterally off tympanic membrane and out of canal

Cartilaginous (outer 1/3) -
Hair, sebaceous and ceruminous glands (wax), barrier foreign objects

Bony party (inner 2/3)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Common conditions of external acoustic meatus

A

Wax/ foreign bodies

Otitis externa - inflammation of external ear -> malignant (immunocomprimised , excruciating, infection involving bone, can be fatal)

Can be seen with an otoscope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Common abnormalities of tympanic membrane

A

Pressure changes change shape, normally pointing slightly out

Bulging secondary to bacterial acute otitis media

Retracted and evidence of fluid - otitis media with effusion or glue ear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a cholesteatoma?

A

Retraction of pars flaccida (Tm) forms a pocket

  1. Eardrum sucked in due to -ve pressure from black game of Eustachian canal
  2. Pocket forms and skin cells collect - early choesteatoma cyst forms
  3. Cholesteatoma grows, grows in destroys middle ear & then may damage inner ear/ nearby skull/ brain

Painless, smelly otorrhea +/- hearing loss

Slowly grows, enzymatic bony destruction (erode ossicles, mastoid/ petrous bone, cochlea)

Rare

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the acoustic reflex?

A

Tensor tympani and stapedius muscles tamper ossicle movement, contract XS vibration loud noise (protective acoustic reflex)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is otosclerosis? What does it lead to?

A

Both genetic and environmental causes

Ossicles fuse at articulations due to abnormal bone growth particularly between base plate of stapes and oval window, sound vibrations cannot be transmitted effectively to cochlea ->

Gradual uni or bilateral conductive hearing loss

One of the most common causes acquired hearing loss in young adults

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How does the middle ear equilibrate pressure?

A

Mucous membrane of middle ear continuously reabsorption air causing -ve pressure

Pharyngotympanic/ Eustachiantube allows equilibration of pressure within ear cavity and atmosphere

Allows ventilation and drainage of mucous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is glue ear?

A

otitis media with effusion

Eustachian tube dysfunction - fluid and -ve pressure in middle ear - decreased mobility of Tm (Retracted) and ossicles affecting hearing

Most resolve spontaneously 2-3 months

May persist - impede speech and language/ development school, increased risk of infection

✅ grommets (tympanostomy tube) maintains equilibration of pressures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is acute otitis media, cause and symptoms?

A

Acute middle ear infection, more common infants

  • otalgia
  • temperature
  • red/ bulging Tm and loss of normal landmarks

Most viral aetiology, occasional bacterial (streptococcus pneumonIae, haemophilus influenza)

17
Q

Why is acute otitis media and glue ear more common in infants?

A

Pharyngotympanic tube shorter and more horizontal

Easier passage for infection from nasopharynx -> middle ear

Tube can block more easily, compromising ventilation/ drainage

18
Q

Complications of acute otitis media

A

Tympanic membrane perforation -> pain clears—> discharge

Facial nerve involvement, rare (close facial canal, 2 intrapetrous branches through middle ear (chorda tympani, Nerve to stapedius)

Life threatening but rare: mastoiditis, meningitis, sigmoid sinus thrombosis, brain abscess

19
Q

What is mastoiditis?

A

Middle esrncommunicates via mastoid antrum with mastoid air cells - potential route infections spread into mastoid bone

Swollen red mastoid process, ear turned inwards

20
Q

How do we hear?

A

Auricle and external auditory canal focuses and funnels sound waves towards tympanic membrane which vibrates ->
Vibration ossicles (stapes at oval window) ->
Vibrations cochlear fluid->
Sensed by Stereocilia in cochlear duct which move in ‘organ of corti’ ->
APs cochlear part CN8 ->
Primary auditory cortex in temporal lobe makes sense of input

21
Q

What is the vestibular apparatus made up of

A

Included the semicircular ducts, saccule, utricle (fluid-filled tubes sacs containing stereocilia) -
Fluid movements due to moving head bend stereocilia -> APs CN8 -> brain

Perceive and maintain sense of balance

22
Q

What are stereocilia and where are they found?

A

Specialised hair cells that generate action potentials when moved

Cochlear duct
Vestibular apparatus
Vas deferens
Epididymis

23
Q

What is presbycusis?

A

Sensorineural hearing loss associated with old age - bilateral and gradual ✅hearing aids

24
Q

what is Benign paroxysmal positional vertigo?

A

Vertigo only
Short-lived episodes triggered by movement of head

Dix-hallpike used diagnosis
Epley manoeuvres treatment

25
Q

What is Meniere’s disease?

A

Vertigo, hearing loss, tinnitus (typically unilateral)

Aural fullness, nausea, vomiting sometimes

Symptoms longer 30mins, recurrent

Hearing may deteriorate over time

(Too much endolymph in inner ear)

26
Q

What’s the difference between acute labrynthitis and acute vestibular neuronitis?

A

Both history URTi

AL - involvement of all inner ear structures, hearing loss, tinnitus, vomiting, vertigo

AVN- usually no hearing disturbance or tinnitus, sudden onset vomiting and severe vertigo (days). Just vestibular components of inner ear.

27
Q

What’s the order in which you would carry out if someone presented with hearing loss?

A

History

Examination (inspection/ palpitation external ear & otoscopy)

Gross hearing assessment (whisper word/ number patient repeat back while masking other ear)

Tuning forks test (Weber’s and Rinne’s)

Referral for more formal audiometry test (pure tone audiometry)

28
Q

Conductive hearing loss vs sensorineural

A 
C - pathology of external or middle ear
Wax
Acute otitis media
OM with effusion 
Otosclerosis
S- pathology involving inner ear or Cn8 
Presbyacusis
Noise-related
Ménière’s disease
Ototoxic medications 
Acoustic neuroma

S3 AHNNAS (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions