Lecture 20 Content Flashcards
Describe the Auditory canal?
- Skin of canal innervated by CN X (vagus)
- tympanic membrane (ear drum) = 2 layers
- external auditory canal = Cartilage + meatus (bone)
- TMD = TMJ dysfunction (shared nerves)
What makes up the middle ear?
outer ear/ear drum + pharynx + mastoid sinus + inner ear
What does the petrosal portion of the ear do?
Massive
- protect inner and middle ear
How is the ear drum placed in the auditory canal?
it is stretched across
What is on the lateral border of the middle ear?
tympanic membrane collects sound waves
What is on the medial border of the middle ear?
bony wall separating middle ear from inner ear
What is on the superior border of the middle ear?
petrous portion of the temporal bone
What is on the posterior border of the middle ear?
pneumatized (mastoid antrum)
What is on the anterior border of the middle ear?
opening of the auditory (eustachian tube)
what are the 3 auditory ossicles?
malleus, incus, stapes
What do the auditory ossicles do?
they carry vbrations from ear drum > oval window
what muscle is connecting the malleus and what attaches to the stapes?
malleus - tensor tympani muscle
stapes - stapedius muscle
What does the tympanic membrane do in hearing?
(tympanic reflex)
- tensor tympani places tension across eardrum
- stapedius “locks down the ossicular chain
= dampens vibration from excessively loud sounds
Describe the Auditory tube? or Eustachian tube?
Connects middle - ear to pharynx
- tube is supported by muscle and cartilage
- EQUALIZES pressure across tympanic membrane
What can happen when fluid builds up in the auditory tube?
- will become inflamed and will swell shut
- fluid can be trapped in middle ear
- fluid build up, and pressure = pain
- threatens the ear drum and sense of hearing/ balance
What can happen when fluid builds up in the auditory tube?
- will become inflamed and will swell shut
- fluid can be trapped in middle ear
- fluid build up, and pressure = pain
- threatens the ear drum and sense of hearing/ balance
What is a Myringotomy?
- drainage tube
- insertion of tube tat perfortrates the ear drum
- release fluid / pressure in the middle ear
- if fluid is not released infection can spread - - on dif. notecard