what is composed of flexible cartilage which is enclosed with skin?
auricle (pinna)
what is slightly curved, contains sebaceous and ceruminous glands?
external auditory meatus
The external ear consists of
The auricle(pina), and external auditory meatus.
what separates the external and middle ear and vibrates when hearing?
tympanic membrane
what is hammer-shaped and transmits vibrations from eardrum to inner ear?
malleus
what is the most superior part of the cavity and is a moveable joint; is anvil-shaped, the largest ossicle; transmits vibrations from malleus to stapes; articulates with head of the malleus
Incus
what is the Smallest ossicle, the smallest bone in the human body; stirrup shaped; footplate goes into an oval window.
stapes
what contains auditory ossicles and is between the medial part of the eardrum and bony wall of the inner ear?
tympanic cavity
what connects the middle ear to the nasopharynx, is 4cm, travels downward, and maintains an equal amount of pressure on both sides of the tympanic membrane; pressure allows air to flow from the nasal cavity to the middle ear?
Beginning of eustachian tube
the middle ear consists of?
the tympanic membrane, auditory ossicles; malleus, incus, Stapes
What have hollow channels filled with perilymph fluid (plasma & CSF)
bony labyrinth
what is associated with equilibrium?
the vestibule and three semicircular canals- bony labyrinth
what consists of the inner ear?
bony labyrinth, membranous labyrinth, oval window, round window, cochlea, semicircular canals
what is the main hearing organ, spiral-shaped embedded into the temporal bone and connected to the cerebrum by the vestibulocochlear nerve?
Cochlea
the cochlea is divided into 3 chambers
scala vestibuli, scala tympani, scala media
what is filled with perilymph?
scala vestibuli
what is considered as the second chamber within the cochlea?
scala tympani
what is located on the cochlear duct, third chamber, and contains endolymph
scala media
what is located between the scala vestibule and tympani
cochlear duct
what is seperated by the vestibular membrane?
scala vestibuli
what is separated by a basilar membrane?
tympani
what holds the organ of corti?
basilar membrane
what is formed with auditory receptors cells, receives/conducts sound stimulus, hair cells in the organs of corti stimulates cochlear nerve
organ corti
what is converted into info for the brain to process in the cochlea and is known as the sensorineural mechanism
Nerve impulses
nerve impulses travel to?
common vestibule, auditory area, central nervous system (temporal lobe)
a series of vibrations is often referred to as?
sound waves
sound travels from
the outer ear, middle ear, malleus, incus, stapes, move in out of the oval window, inner ear, cochlea
What causes damage to stapes?
osteosclerosis
osteosclerosis is?
an abnormal growth of bone that hardens at the base of the stapes in the middle ear resulting in hearing loss due to the inability to vibrate.
who discovered osteosclerosis?
Antonio Maria Valsalva
hearing loss due to a lesion or disorder affecting ear canal/ middle ear
conductive hearing
hearing loss due to a disorder in the inner ear or affecting the 8th cranial nerve (vestibulocochlear nerve)
sensorineural hearing
Biology confirmed with
audiogram and CT scan
who is affected by otosclerosis?
3 million American 10% of the population
Caucasian or Asian American
Ages between 10-30
women
pregnant women
Gene (25% if one parent, 50% if both parent)
Treatment:
originally entire stapes was removed
currently entire removal of stapes is removed if stapes is SEVERELY damaged
what is used to gain function and movement of stapes in order to restore hearing
Prosthesis
what is the most used prosthetics?
its comprised of a piston with a wire loop.
what type of prosthetics is used to crimp the wire loop around the incus
laser
reasons why surgery may not be recommended
active external or middle ear infection
pre-existing perforation of the tympanic membrane
Patient anatomy (inner ear malformations)
poor physical health
What is the second most common cause of failure
necrosis of the incus
Patient positioning is?
supine and head turned to the non-operative side
Patient prep:
patient eyes are taped
circulator places grounding pad on thigh
Surgeon shaves small amount of hair behind the ear using clippers
patient prepped with betadine
Patient draping
surgical tech drapes microscope
patient is draped with an aperture drape and followed with ENT split drape
Anesthesia:
general anesthesia administered a dose of 1% lidocaine with 1:100,000 of epi auricle and ear canal
wound is closed with
3-0 polyglactin on 910 suture, tissue adhesive, and steri strips.
a measurement of the length from the underside of the incus to the hole made in the footplate is made for
the prosthesis using the measuring rod.
Dressings:
Wicks soaked in saline may be placed for any drainage
Bacitracin may also be injected into the ear
A cotton ball covered in bacitracin is placed into the ear
The dressing is applied and then fastened around the head.
Recovery -> post-op for patients:
avoid driving for at least a week to avoid inflammation and possible displacement
The patient will receive antibiotic drops for the following week
packing and suturing will be removed from the ear in 7 days.
Avoid lifting heavy objects Ride in an airplane, blow their nose
swim for three weeks
do not get your ear wet to avoid inner ear infections can cause hearing loss
avoid loud noises.
Audiogram is done for aftercare between?
1-4 months
An audiogram is done depending on?
how long patient can regain hearing
for revision surgery audiogram will not be done until?
3-6 months.