Tympanic Membrane- - Lateral WallThree-layersmembraneOuter epithelial layer laterally （continuouswithexternal auditorymeatusMiddle fibrous layer (have three fibres:theradial,circular,parabolic.Inner mucosal layer (continuous withrespiratory mucosa of middle ear)
Tympanic Membrane- - Lateral Wall ◼ Three-layers membrane ◼ Outer epithelial layer laterally ( continuous with external auditory meatus) ◼ Middle fibrous layer (have three fibres:the radial,circular,parabolic.) ◼ Inner mucosal layer (continuous with respiratory mucosa of middle ear)
Tympanic Membrane - Lateral WallTM adherentto:Physiologicarea is 17timesmalleusat umboand lateralthat of oval window (soundprocesspressure amplified byfactorTympanicring at fibrous annulus.of 17).Pars Tensa -circular fibersLongcrusof incusSound conductionPosteriormallearfoldParsflaccidaPars Flaccida- elastic fibersAnteriormallearfoldentrancetoepitympanumLateralprocessofmalleusParstensaManubriumofmalleusUmboConeoflightRighttympanicmembrane(eardrum)viewedthroughspeculum
Tympanic Membrane - Lateral Wall ◼ TM adherent to : ◼ malleus at umbo and lateral process ◼ Tympanic ring at fibrous annulus. ◼ Pars Tensa - circular fibers. Sound conduction. ◼ Pars Flaccida - elastic fibers. entrance to epitympanum. ◼ Physiologic area is 17 times that of oval window (sound pressure amplified by factor of 17)
Tympanic Membrane - Lateral Wall.Withoutan annulus,ParsLong crusofincusflaccida.May hidePosteriormallearfoldParsflaccidacholesteatomaAnteriormallearfold.Sensory:lateral from V,VII,IXLateralprocessofmalleusXParstensaManubriummedial from tympanic plexus ofofmalleusUmboIXConeof lightVasc:auricular(lateral)Righttympanicmembrane (eardrum)viewedthroughspeculumtympanic(medial)branchesof internal maxillary
Tympanic Membrane - Lateral Wall •Without an annulus, Pars flaccida. May hide cholesteatoma •Sensory: lateral from V, VII, IX, X medial from tympanic plexus of IX •Vasc: auricular (lateral), tympanic (medial) branches of internal maxillary
Clinical Correlation - PerforationPlate 76.Near-total perforation with dry middlePlate77.Spontaneouslyhealedposterior-inferiorear.perforation
Clinical Correlation - Perforation
Middle Ear Anatomy - WallsShortcrusonteriorprocessofmalleusRoof:PosteChordatympaninerveTegmenTympani-flooriormallearfoldof Middle Cranial FossaanimuscleAthinplateof boneExtendposteriorlytoform theroof of aditusandantrumThefloor of middlecranialfossa
Middle Ear Anatomy - Walls ◼ Roof: ◼ Tegmen Tympani – floor of Middle Cranial Fossa ◼ A thin plate of bone ◼ Extend posteriorly to form the roof of aditus and antrum ◼ The floor of middle cranial fossa