Ear
Components covered in this ear section:
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Outer Ear
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Middle Ear
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Inner Ear
Outer Ear
Outer ear:
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Helix
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Antihelix
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Tragus
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Antitragus
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External acoustic meatus
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Lobule
Middle Ear
Middle ear:
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Tympanic membrane
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Ear ossicles
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Muscles
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Communications
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Chorda tympani nerve
Tympanic Membrane
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Tympanic membrane- in contact with external ear
Ear Ossicles
Ear ossicles:
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Hammer/Malleus- in contact with tympanic membrane
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Anvil/Incus
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Stirrup/Stapes- in contact with oval window
Muscles
Muscles related to the ear ossicles:
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Tensor tympani- pulls malleus medially tensing tympanic membrane (decreasing amplitude of oscillations)
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Innervated by CN V3 (mandibular nerve)
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Stapedius- pulls stapes posteriorly (decreasing oscillation range)
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Innervated by CN VII (facial nerve)
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Communications
Communications:
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Pharyngotympanic/eustachian tube- connected anteromedially to nasopharynx
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Mastoid air cells- connected posterosuperiorly to mastoid antrum
Chorda tympani nerve
Chorda tympani nerve:
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Branches off CN VII (facial nerve) in middle ear
Inner Ear
Inner ear contains:
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Bony labyrinth- series of bone lined chambers containing perilymph fluid
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Membranous labyrinth- membranous chambers inside bony labyrinth containing endolymph fluid
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CN VIII (vestibulocochlear nerve)
Bony Labyrinth
Bony labyrinth:
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Vestibule
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3 Semicircular canals
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Anterior semicircular canal
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Lateral semicircular canal
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Posterior semicircular canal
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Ampulla- dilatation at the end of SCCs
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Cochlea
Membranous Labyrinth
Membranous labyrinth:
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2 sacs
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Utricle
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Saccule
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3 semicircular ducts
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Anterior semicircular duct
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Lateral semicircular duct
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Posterior semicircular duct
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Cochlear duct