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
Section2Middleear.liesbetweentheexternaland internalears·includes the tympanic cavity, auditory tube and mastoid cells·transmitsoundwaveinternalearexternalearmiddleear
• lies between the external and internal ears • includes the tympanic cavity, auditory tube and mastoid cells • transmit sound wave Section 2 Middle ear
I.Tympaniccavity·anirregularair-filledspacewithinthetemporal bone·contains the auditory ossicles,ligments,muscles and nerves· communicates with the nasopharynx anteriorly through the auditorytubeand withthe mastoid cells posteriorlythroughthe mastoid antrumexternalearmiddleearinternalear
Ⅰ. Tympanic cavity • an irregular air-filled space within the temporal bone • contains the auditory ossicles, ligments, muscles and nerves • communicates with the nasopharynx anteriorly through the auditory tube and with the mastoid cells posteriorly through the mastoid antrum
1.Wallsofthetympaniccavity(1) Lateral / membranous wall: is separted from extenal meatus by tympanic membrane(2) Superior / tegmental wall: separates the middle cranial fossa(3)Inferior/jugularwall:separatesthejugularfossaMiddlecranialfossa
(1) Lateral / membranous wall: is separted from extenal meatus by tympanic membrane (2) Superior / tegmental wall: separates the middle cranial fossa (3) Inferior / jugular wall: separates the jugular fossa 1. Walls of the tympanic cavity Middle cranial fossa
(4)Anterior/ carotidwall: separatesthe internal carotidA(5)Posterior/mastoidwall:isopenedintothetympanicantrumTympanicantrumTympaniccavityMastoidprocessICA
(4) Anterior / carotid wall: separates the internal carotid A. (5) Posterior / mastoid wall: is opened into the tympanic antrum ICA Tympanic antrum Mastoid process Tympanic cavity
middle earinternalearexternal ear6. Medial / labyrinthine wall·Promontory·Fenestra vestibuliFenestracochlea·Prominence of facial canalProminenceoffacial canalFenestra vestibuliPromontoryFenestra cochlea
6. Medial / labyrinthine wall • Promontory • Fenestra vestibuli • Fenestra cochlea • Prominence of facial canal Prominence of facial canal Fenestra vestibuli Promontory Fenestra cochlea