Y DOES CAHART NOTCH OCCUR????
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Y DOES CAHART NOTCH OCCUR????
u ppl ll be familiar with the term cahart notch !! ie., the dip in bone conduction curve at 2000Hz freq cf of OTOSCLEROSIS.. . .
can anyone explain y does it appear?? ? ? ?
can anyone explain y does it appear?? ? ? ?
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Re: Y DOES CAHART NOTCH OCCUR????
to understand y it occurs lets see the bone conduction first
BONE CONDUCTION:
sound from the environment r transferred to ear thru vibration of TM(air conduction)
and bone conduction.
bone conduction has TWO ROUTES -->
1) thru vibrations of skull
2) and thru vibraton of ossicles (vibrations of skull secondarily vibrates the ossicles which then transmittd thru round window and ABLE to hear )
normally the 1 & 2 doesnt occur at the same time. there is a time lag. . WHICH RESULTS IN OSSICULAR INERTIA. this is very impt for a bone conduction to be normal
now in otosclerosis foot plate of stapes is fixed. so now the skull and the ossicles are a single unit . ie both vibrates at the same time -
LOSS IN OSSICULAR INERTIA which results in loss of bone conduction in otosclerosis.
but y does it occur only at 2000Hz ??
for every freq a particular str is vibratd (*2) . and for 2000Hz freeq the str vibrated is the foot plate of stapes .
thats y in otosclerosi where v see fixation of stapes foot plate . loss of ossicular inertia ocuurs particularly for 2000hz and the loss is there at 2000Hz resulting in the CAHARTS NOTCH
thnx for hearing the story ..!! hope u understood!!!
BONE CONDUCTION:
sound from the environment r transferred to ear thru vibration of TM(air conduction)
and bone conduction.
bone conduction has TWO ROUTES -->
1) thru vibrations of skull
2) and thru vibraton of ossicles (vibrations of skull secondarily vibrates the ossicles which then transmittd thru round window and ABLE to hear )
normally the 1 & 2 doesnt occur at the same time. there is a time lag. . WHICH RESULTS IN OSSICULAR INERTIA. this is very impt for a bone conduction to be normal
now in otosclerosis foot plate of stapes is fixed. so now the skull and the ossicles are a single unit . ie both vibrates at the same time -
LOSS IN OSSICULAR INERTIA which results in loss of bone conduction in otosclerosis.
but y does it occur only at 2000Hz ??
for every freq a particular str is vibratd (*2) . and for 2000Hz freeq the str vibrated is the foot plate of stapes .
thats y in otosclerosi where v see fixation of stapes foot plate . loss of ossicular inertia ocuurs particularly for 2000hz and the loss is there at 2000Hz resulting in the CAHARTS NOTCH
thnx for hearing the story ..!! hope u understood!!!
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Re: Y DOES CAHART NOTCH OCCUR????
i indeed did
good one
good one
gogeta- NeWBie
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