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The vestibulocochlear organ
广西医科大学解剖学教研室
劳明 制作
Copyright @2003 lao ming All rights reserved
Composition
The vestibulocochlear (ear)
External ear
Middle ear
Internal ear
The external ear
1.the auricle
the auricle
External acoustic meatus
tympanic membrane
1) location
each side of the head
2) Structure
Elastic fibrocartilage
covered with skin
(Lack of fat)
3)shape:
auricular lobule
external acoustic pore
2.External acoustic meatus
1)Two parts
Cartilagious part
Bony part
2) Covered with
skin closely
3) curve
Lat.—forwards
upwards
Med.—forwards
downwards
3.The tympanic membrane
*two parts: flaccid & tense part
*cone of light (bright area)
on anterioinferior to the umbo
of tympanic membrane
* to observe cone of light
the auricle should be drawn
upwards backwards in adult.
downwards backwards in children .
▲thin, semitransparent
▲ act as the floor of meatus ,45 °obliquely
▲ concave outside
The middle ear
Tympanic cavity
Auditory tube
Mastoid air cells
1.Tympanic cavity
1)The six walls
superior wall (tegmental wall)
inferior wall (jugular wall)
anterior wall(carotid wall)
posterior wall (mastoid wall )
lateral wall (membranous wall )
medial wall (labyrinth wall)
(Key & difficult point)
2)The chain of auditory
ossicles & muscles
in tympanic cavity
1). malleus → incus→stapes
↓
↓
(Tympanic
Membrane)
2).Tensor tympanic
Stapedius
( fenestra
vestibuli)
2.Auditory tube
*two parts: bony & cartliginous parts
*two openings: pharyngeal & tympatic orifices
*auditory tube in children
is shorter,
wider and more
horizontal
(inflammation of the
pharynx causes otitis
media easily
in children)
中耳 位于外耳和内耳之间。包括鼓室、
3.The mastoid antrum & cells
in the mastoid
The internal ear (labyrinth)----( two parts)
bony
bony
Semicircular
Cochlea
vestibule
labyrinth
canals
Cochlear
Membranous semicircular Utricle
saccule duct
ducts
labyrinth
1. The bony semicircular canals
• 3 in number (anterior, posterior and lateral ~)
• 5 crura
• 3 ampulla
2.vestibule
•Fenestra ventibuli—closed by the stape
•Fenestra cochleae---closed by second
tympanic
membrane
vestibule
3.The cochlea
bony canals of cochlea
winding for 2 1/2 around
central modilus
three parts:
Scala vestibuli
cochlear duct
scala tympani
The membranous labyrinth
Semicircular
ducts
utricle
saccule
Cochlear
duct
The Receptors inside
membranous labyrinth
1.ampulary crest
organ of kinetic balance
2.maccuae of saccule and utricles
organ of static balance
3.spiral organ (Corti’s apparatus)
for auditory sensation
Corti’s apparatus
Perilymph & Endolymph
Perilymph: between bony & membranous labyrinth
Endolymph: within membranous labyrinth
The conduction of sound:
air conduction
conduction of sound: air conduction
The sound wave → the external acoustic meatus
→ tympanic membrane → chain of the auditory
ossicles → fenestra vestibuli → the perilymph
within the scale vestibuli → the endolymph within
the cochlear duct → the spiral organ →nerve
impulse