Middle Ear Flashcards
The function of the middle ear is to…
Transmit sound from acoustical energy to mechanical energy
The middle ear cavity is air filled or fluid filled?
Air filled
The superior portion of the middle ear cavity is called the…
Epitympanic Recess
The bulge of the cochlea into the middle ear cavity is called the…
Promontory
The outer rim of the tympanic membrane is called the…
Tympanic Annulus
The major portion of the tympanic membrane that makes up 1/9 of it by area
Pars flaccida
The major portion of the tympanic membrane that makes up 8/9 of it by area
Pars tensa
When performing otoscopy on a patient’s left ear, the cone of light would be at…
7 o’clock
The ossicles are suspended in the middle ear cavity.
True
The footplate of the stapes makes contact with which structure?
Oval window
Which part of the malleus makes contact with the tympanic membrane?
Manubrium (Handle)
The two muscles suspending the ossicles in the middle ear cavity are the _______ and the _______.
Stapedius muscle
Tensor tympani muscle
What is the function of the ossicles?
The ossicles collectively transmit sound from the tympanic membrane to the cochlea
Name the structure that controls the pressure of the middle ear
Eustachian Tube
The first 1/3 of the eustachian tube is the ____ portion and is ___ mm long
Bony
12
The remaining 2/3 of the eustachian tube is the ____ portion and is ___ mm long
Cartilaginous
18-24
The eustachian tube opens when a person is _____, _____ or experiences _____
Chewing
Yawning
A change in atmospheric pressure
The eustachian tube is controlled by the _____ and _____ muscles
Levator Veli Palatini
Tensor Veli Palatini
What are the differences between adult and pediatric eustachian tubes?
The adult eustachian tube sits at a 45 degree angle, while the pediatric eustachian tube is more flat
What does the tensor tympani do?
Pulls the handle of the malleus medially
Tenses the tympanic membrane
What does the stapedius muscle do?
Dampens vibrations passed to the cochlea via the oval window
The malleus and incus move together in a ______ motion while the stapedial footplate moves in a _____ motion at the oval window
pivot-like
rocking
Impedance is the…..
The opposition to the flow of energy or the reluctance to accept energy
A mismatch in impedance in the auditory system is caused by _____.
A difference in impedance between air (the conductive medium of the middle) and fluid (specifically perilymph, the conductive medium of the scala vestibuli and scala tympani).
Name the three components of the middle ear transformer
Area differential between the TM and stapedial footplate
The lever action of the ossicular chain
The buckling effect of the curved membranous structure of the TM
Rank the three components of ME transformer by contribution
Area differential between the TM and stapedial footplate
The buckling effect of the curved membranous structure of the TM
The lever action of the ossicular chain
What is the total effect of the ME transformer?
40:1 or 32 dB increase in gain that allows the middle ear to overcome impedance mismatch
The ME transformer does not change by frequency
False, it dampens low frequency sounds
What is the resonance of the ossicles?
2 kHz
What is the resonance of the middle ear collectively?
800 - 1200 Hz
What is the source of the occlusion effect?
When sound is trapped in the inside the EAC, the trapped sound is amplified
Label the middle ear
Label the middle ear
Label the ossicles
