VestibulocochlearOrganExternal earcollecting&transmittingsoundwavesMiddle earreceivethestimulationofbothsoundwavesInternalearandchangesofthepositionoftheheadexternal earmiddleearinternalear
Vestibulocochlear Organ External ear Middle ear Internal ear collecting & transmitting sound waves receive the stimulation of both sound waves and changes of the position of the head
Section1 ExternalearI .AuricleII.ExternalacousticmeatusIII.Tympanic membraneexternalearmiddleearinternalear
Section 1 External ear Ⅰ. Auricle Ⅱ. External acoustic meatus Ⅲ. Tympanic membrane
I.Auricle·iscomposedofathinplateofelasticfibrocartilagecoveredwithskin·Shell-like,collectthesoundwave·Auricularlobule·Externalacousticporemiddleearinternalearexternalear
Ⅰ. Auricle • is composed of a thin plate of elastic fibrocartilage covered with skin • Shell-like, collect the sound wave • Auricular lobule • External acoustic pore
I.Externalacousticmeatus·Externalacousticpore→tympanicmembrane.·2.5cmlength,S-shapedcurvaturepassageway·Lateral 1/3 cartilaginous part: runs forwards and upwards, then backwards·Medial2/3bony part:runsforwards and downwards-WhiletoexamineorchecktympanicmembraneInadult:pulltheauricleposteriorly& superiorlyInchildren:pulltheauricleposteriorly&inferiorlymiddleearinternalearexternalear
Ⅱ. External acoustic meatus • External acoustic pore → tympanic membrane. • 2.5 cm length, S-shaped curvature passageway • Lateral 1/3 cartilaginous part: runs forwards and upwards, then backwards • Medial 2/3 bony part: runs forwards and downwards ☞ While to examine or check tympanic membrane In adult: pull the auricle posteriorly & superiorly In children: pull the auricle posteriorly & inferiorly
III.Tympanicmembrane·oval in shape,thinand semi-transparent·separatesthemiddle earfromtheexternal acousticmeatus· it inclines greatly and forms an angle of 45° with the floor of the meatus.·superior1/4flaccidpart+②inferior3/4tensepart·umbo: outer surface of the membrane is concave with a centraldepression.handle of the malleus is firmly attached to the inner surface of the umboMalleusUmbo2
Ⅲ. Tympanic membrane ① ② • oval in shape, thin and semi-transparent • separates the middle ear from the external acoustic meatus • it inclines greatly and forms an angle of 45°with the floor of the meatus. • ① superior 1/4 flaccid part + ② inferior 3/4 tense part • umbo: outer surface of the membrane is concave with a central depression • handle of the malleus is firmly attached to the inner surface of the umbo Umbo Malleus