1. Anatomy of ear
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2. components
Auricle
External acoustic canal
Tympanic membrane
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3. Auricle /pinna
single piece of yellow elastic cartilage covered with skin
Closely adherant to perichondrium on lateral surface than
medial
Incisura terminalis: no cartilage between tragus n crus of
helix .incision in this area for epidural approach use: as
source of source of graft for reconstruction surgery of middle
ear etc
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4. External acaustic /auditory canal
24 cms along posterior wall
 upper wall directed upwards, backwards, medially
Inner part: downwards, forwards ,medially
For allignment :pulled upwards, backwards, medially
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5. (a)Cartilagenous part
8mm
has 2 deficiencies:fissure of santorini; part through which
parotid or superior mastoid infection occur
Furuncles(staphylococcal infection) in outer 1/3 of canal due
to hair follicles

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6. (b)Bony part
16mm devoid of hair, ceruminous glands
6mm lateral to tympanic membrane bony meatus presents
narrowing :”isthmus”
Anteroinferior part of deep meatus beyond isthmus presents
recess-”ant recess”
Anteeroinferior part of bony canal may presents deficiency
(foramen of huschke)
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8. Tympanic memb/ear drum
9-10mm tall,8-9mm wide,.1mm thick
Divided into 2 parts
(a) pars tensa
Thick perifery ,form fibrocartlagenous ring called ”annulus
tympanicus”
Central part tensed inwards at tip of malleus ‘UMBO’
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9. (b)Pars flacida /shrapnels membrane
Between notch of rivinus n anterior n posterior malleal folds
LAYERS OF TYMPANIC MEMBRANE
Outer epIthelial layer
Inner mocosal layer
Middle fibrous layer
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10. Nerve supply of external ear
Greater auricular nerve
Lesser occipital nerve
Auriculo temporal nerve
Auricular branch of vagus
EXTERNAL AUDITORY CANAL
Facial nerve
Auriculo temporal nerve
Auricular br of vagus nerve
TYMPANIC MEMBRANE
Auriculo temporal nerve
Auri br of vagus nerve
Jacobsons nerve
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11. MIDDLE EAR
Middle ear cleft: eustachian tube,aditus,antrum,mastoid air cells
Divided into: mesotympanium,epitympanum,hypotympanum
Linked to 6 sided box
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12. roof
Formed by thin plate of bone : tegmen tympani,forms
roof of aditus n antrum
FLOOR
Thin plate of bone seperates tympanic cavity from jug bulb
ANTERIOR WALL
Thin plate of bone seperates cavity from internal carotid
art
2 openings: eustachian tube, tensor tympani muscle
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13. Posterior wall
Close to mastoid air cells
Presents bony progectn”pyramid”,tendon of stapedius is
attachad to neck of stapes
Surgically important as direct access can be made through
middle ear
Facial recess/ posteauor sinus: depression in post wall lateral
to pyramid
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14. Medial wall
Formed by labyrinth
Presents bulge” promontary”
Oval window fixed to foot plate
Round window covered by sec tympanic membrane
Over oval window is canal for facial n
Just anterior to oval window, hook like progection” pocessus
cochleariformis”
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15. Lateral wall
Formed by tympanic membrane n bony outer attic wall
”scutum”
 OSSICLES OF MIDDLE EAR
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16. Malleus:head,neck,handle,lateral and anterior process
Incus:body,short and long process
Stapes: head, neck, anterioe and posterior crura, foot plate
INTRA TYMPANIC MUSCLES
Tensor tympani
stapedius
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17. THE INTERNAL EAR
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18. Bony and membranous labyrinth filled with endolymph and
perylymph respectively
 Bony labyrinth
3 parts:vestibule,semicircular canals,cochlea
Vestibule:the central canal of labrynth
Latwral wall:oval window
Medial wall: 2 recess: spherical and elliptical
Below opening of elliptical recess is opening of aqueous duct
through which passes endolymphatic duct
Posterior part of vestibule:5 openings of semisircular canals
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19. Semicircular canals3 in number: lateral,posterior,superior at right angles to each
other
Has amputated n nonamputated end,
Nonamputated ends of posterior n superior canals unite to form
channel ”crus commune”
 conchae
Coiled tube making2.5-2.75 turns round central pyranid
”modiolus”
“osseous spiral lamina”:around modiolus winding spirally like
thread of screw
3 componants:
 scala vestibuli
 Scala tympani
 Scala mediapgmedicalworld.com

20. THANK YOU
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