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02/07/0802/07/08 Tinnitus Support GroupTinnitus Support Group 11
Anatomy and Physiology of the Ear
Anatomy and Physiology Anatomy and Physiology of the Earof the Ear
Eslam Osman, M.D.,F.R.C.S (ORL, H&N Surgery)Eslam Osman, M.D.,F.R.C.S (ORL, H&N Surgery)
02/07/0802/07/08 Tinnitus Support GroupTinnitus Support Group 22
Divisions Of The EarDivisions Of The EarDivisions Of The Ear
External EarExternal EarMiddle EarMiddle EarInner Ear Inner Ear Central Auditory Nervous SystemCentral Auditory Nervous System
02/07/0802/07/08 Tinnitus Support GroupTinnitus Support Group 44
Structures of the Outer Ear Structures of the Outer Ear
PinnaPinnaCollect soundCollect soundLocalizationLocalizationResonatorResonatorProtectionProtection
02/07/0802/07/08 Tinnitus Support GroupTinnitus Support Group 55
External Auditory CanalExternal Auditory Canal
Extends from the pinna to the Extends from the pinna to the tympanic membranetympanic membrane1 1/2 inch in length1 1/2 inch in lengthProtects the eardrumProtects the eardrumWaxWax
02/07/0802/07/08 Tinnitus Support GroupTinnitus Support Group 66
Structures of the Middle EarStructures of the Middle Ear
Tympanic Membrane Tympanic CavityOssiclesMiddle Ear MusclesEustachian TubeMastoid
02/07/0802/07/08 Tinnitus Support GroupTinnitus Support Group 77
Tympanic MembraneTympanic Membrane
The eardrum separates the outer ear The eardrum separates the outer ear from the middle earfrom the middle earCreates a barrier that protects the Creates a barrier that protects the middle and inner areas from foreign middle and inner areas from foreign objectsobjectsThe eardrum vibrates in response to The eardrum vibrates in response to sound pressure waves. sound pressure waves. Changes acoustic energy into Changes acoustic energy into mechanical energymechanical energy
02/07/0802/07/08 Tinnitus Support GroupTinnitus Support Group 88
OssiclesOssicles
Malleus (hammer)Malleus (hammer)Incus (anvil)Incus (anvil)Stapes (stirrup) smallest bone of the Stapes (stirrup) smallest bone of the bodybody
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Middle Ear MusclesMiddle Ear MusclesTensor tympaniTensor tympani•• Attached to malleusAttached to malleus
StapediusStapedius•• Attached to stapeAttached to stape
Middle Ear Muscle Function:Middle Ear Muscle Function:•• Help maintain ossicles in proper positionHelp maintain ossicles in proper position•• Protect inner ear from excessive sound levels Protect inner ear from excessive sound levels •• This protective reflex termed "acoustic reflex"This protective reflex termed "acoustic reflex"
02/07/0802/07/08 Tinnitus Support GroupTinnitus Support Group 1010
Eustachian TubeEustachian Tube
The ET connects the front wall of the The ET connects the front wall of the middle ear with the nasopharynx middle ear with the nasopharynx It operates like a valve, which opens It operates like a valve, which opens during swallowing and yawningduring swallowing and yawningIt equalizes the pressure on either It equalizes the pressure on either side of the eardrum, which is side of the eardrum, which is necessary for optimal hearing.necessary for optimal hearing.
02/07/0802/07/08 Tinnitus Support GroupTinnitus Support Group 1111
MastoidMastoid
Bony ridge behind the auricleBony ridge behind the auricleConnect with middle earConnect with middle earCan get infected ( Mastoiditis)Can get infected ( Mastoiditis)
02/07/0802/07/08 Tinnitus Support GroupTinnitus Support Group 1212
Function of Middle EarFunction of Middle Ear
ConductionConduction
ProtectionProtection
TransducerTransducer
AmplifierAmplifier
02/07/0802/07/08 Tinnitus Support GroupTinnitus Support Group 1313
AmplifierAmplifier
The middle ear enhances the transfer The middle ear enhances the transfer of acoustical energy in two ways: of acoustical energy in two ways: •• The area of the eardrum is about 17 The area of the eardrum is about 17
times larger than the oval windowtimes larger than the oval windowThe effective pressure (force per unit area) The effective pressure (force per unit area) is increased by this amount. is increased by this amount.
•• The ossicles produce a lever action that The ossicles produce a lever action that further amplifies the pressurefurther amplifies the pressure
02/07/0802/07/08 Tinnitus Support GroupTinnitus Support Group 1414
Structures of the Inner EarStructures of the Inner Ear
CochleaCochlea
VestibuleVestibule
Semicircular canalsSemicircular canals
02/07/0802/07/08 Tinnitus Support GroupTinnitus Support Group 1515
CochleaCochleaSnailSnail--shaped organ shaped organ with a series of with a series of fluidfluid--filled tunnelsfilled tunnelsconverts converts mechanical energy mechanical energy into electrical into electrical energyenergyIt contain It contain Organ of Organ of Corti Corti ( end organ of ( end organ of hearing)hearing)
02/07/0802/07/08 Tinnitus Support GroupTinnitus Support Group 1717
Vestibular SystemVestibular System
Consists of vestibule and three semiConsists of vestibule and three semi--circular canalscircular canalsShares fluid with the cochleaShares fluid with the cochleaControls balanceControls balanceNo part in hearing processNo part in hearing process
02/07/0802/07/08 Tinnitus Support GroupTinnitus Support Group 1818
Central Auditory PathwayCentral Auditory Pathway
Pathway between Pathway between cochlea and cochlea and auditory cortexauditory cortex
Cochlear nerveCochlear nerve
Cochlear nucleusCochlear nucleus
02/07/0802/07/08 Tinnitus Support GroupTinnitus Support Group 1919
Causes of TinnitusCauses of Tinnitus
Local causesLocal causesEvery ear disease can be associated Every ear disease can be associated
with deafnesswith deafness
General CausesGeneral CausesCardiovascular diseaseCardiovascular diseaseNeurological conditionsNeurological conditions
02/07/0802/07/08 Tinnitus Support GroupTinnitus Support Group 2020
Classification of TinnitusClassification of Tinnitus
Unilateral or bilateralUnilateral or bilateralSubjective or objectiveSubjective or objectivePulsatile or non pulsatilePulsatile or non pulsatile
02/07/0802/07/08 Tinnitus Support GroupTinnitus Support Group 2121
Key Points in HistoryKey Points in History
Accompanying ear diseaseAccompanying ear diseaseHistory of noise exposureHistory of noise exposureTraumaTraumaOtotoxic medicationsOtotoxic medicationsSystemic DiseasesSystemic Diseases