The Vestibulocochlear Organ
前庭蜗器
山东大学医学院 解剖教研室
李振华
General Features
Three parts



External ear 外耳: collects
sound waves
Middle ear 中耳: transmits
sound waves
Internal ear 内耳:
containing the organs of
hearing and balanc
External Ear 外耳

Auricle 耳郭
External acoustic meatus 外耳道

Tympanic membrane 鼓膜

Auricle 耳郭
External Acoustic Meatus 外耳道


A slender canal that extends
from external acoustic pore to
tympanic membrane
Two parts





Cartilaginous part－ lateral 1/3
Bony part－medial 2/3
Lined by a layer of thin skin
This S-shaped passage
medially, at first forward and
upward, then backward and,
finally forward and downward
In babyhood, it is shorter and
more horizontal than in adult
Tympanic Membrane 鼓膜



A thin, fibrous membrane that
is pearly gray
Two parts
 Flaccid part 松弛部:
upper 1/8-1/6
 Tense part 紧张部:
lower 7/8-5/6
Umbo of tympanic membrane
鼓膜脐

Cone of light 光锥
Middle Ear 中耳



Tympanic cavity 鼓室
Auditory tube 咽鼓管
Mastoid antrum 乳突窦 and mastoid cells 乳突小房
Tympanic Cavity 鼓室


An air-containing cavity in
the petrous portion of
temporal bone and is
lined with mucous
membrane
Has six walls
Walls of Tympanic Cavity
Roof or tegmental wall 盖壁
Lateral wall or
membranous wall
膜壁
Posterior
Anterior
Wall wall or
or
carotidmastoid
wall
颈动脉壁
wall
乳突壁
Floor or jugular wall 颈静脉壁
Medial wall or
labyrinthine wall
迷路壁
Walls of Tympanic Cavity

Roof or tegmental wall
盖壁



Formed by tegmen
tympani
Separates tympanic cavity
from middle cranial fossa
Floor or jugular wall
颈静脉壁

separates the cavity from
superior bulb of internal
jugular vein
Walls of Tympanic Cavity

Anterior wall or carotid
wall 颈动脉壁

Separates tympanic cavity
from carotid canal,
superiorly lies two
openings:


Upper opening for tensor
tympani muscle
Lower opening for
auditory tube, which
communicates with
nasopharynx
Walls of Tympanic Cavity

Posterior wall or mastoid
wall 乳突壁

Aditus of mastoid antrum
乳突窦入口

Pyramidal eminence 锥隆起
Walls of Tympanic Cavity

Lateral wall or
membranous wall 膜壁


Tympanic membrane
Epitympanic recess
Walls of Tympanic Cavity

Medial wall or labyrinthine wall 迷路壁




Promontory 岬
Fenestra vestibuli 前庭窗:covered by base of stapes
Fenestra cochleae 蜗窗 closeted by secondary tympanic
membrane 第二鼓膜
Prominence of facial canal 面神经管凸
Acute otitis median
急性中耳炎
Perforation, inflammation or
trauma 鼓膜穿孔（炎症或外伤）
Auditory Ossicles 听小骨



Consists of chain of three
bones:
 Malleus 锤骨
 Incus 砧骨
 Stapes 镫骨
Articulate by synovial joints
Transmit vibration of tympanic
membrane to footplate of
stapes in fenestra vestibuli
Muscles of Auditory Ossicles


Tensor tympani 鼓膜张肌
Stapedius 镫骨肌
Auditory Tube 咽鼓管


About 3~4 cm long, extends
from the anterior wall of
tympanic cavity downward,
forward, and medially to the
nasopharynx
Two parts




Bony part: posterolateral 1/3
Cartilaginous part:
anteromedial 2/3
Functions to equalize air
pressure on either side of
tympanic membrane
In childhood, it is shorter,
wider and more horizontal
than in adult
Auditory Tube 咽鼓管
Mastoid Antrum 乳突窦
and Mastoid Cells 乳突小房


Mastoid antrum乳突窦:
a small chamber between
tympanic cavity and
mastoid cells
Mastoid cells乳突小房:


A series of communicating
cavities within the mastoid
process of temporal bone
Continuous above with the
mastoid antrum and the
tympanic cavity
Internal Ear 内耳
General features


Lies within the petrous
portion of temporal bone
Key contents of internal ear
 Bony labyrinth 骨迷路
contains perilymph
 Membranous labyrinth
膜迷路 is filled with
endolymph and contains
the sensory organs
Bony Labyrinth 骨迷路



Cochlea 耳蜗
Vestibule 前庭
Bony semicircular canals 骨半规管
Vestibule 前庭



Hollow bony space
In its lateral wall are the fenestra vestibuli and
fenestra cochleae
Contains utricle 椭圆囊 and saccule 球囊
Bony Semicircular Canals 骨半规管

Semicircular duct in each
(anterior, posterior, and
lateral)

Canal at right angles to
each other

Bony ampullar 骨壶腹
dilated ampulla in each
canal at its end
Cochlea 耳蜗


It somewhat resembles a
snail’s shell
Cupula of cochlea faces
anterolaterally and the base of
cochlea faces posteromedially
Cochlea 耳蜗

Modiolus



蜗轴
Osseous spiral lamina 骨螺旋板
Spiral canal of modiolus 蜗轴螺旋管
contain cochlear ganglion 蜗神经节
Cochlear spiral canal 蜗螺旋管:
makes two and one-half
spinal turns around the
modiolus


Scala vestibuli 前庭阶
Scala tympani 鼓阶
Membranous Labyrinth 膜迷路


Cochlear duct 蜗管
Utricle and saccule
椭圆囊和球囊

Semicircular ducts
膜半规管
INNER EAR ANATOMY: LOCATION OF
SENSORY RECEPTORS
Membranous of ampullae
Cochlear duct
Saccule
Utricle
Cochlear Duct 蜗管
Contains:
 Spinal organ 螺旋器 (of Corti)
 The sound receptors lies on
tympanic wall of cochlear
duct 蜗管鼓壁
Utricle and Saccule 椭圆囊和球囊
Contain:



Macular utriculi 椭圆囊斑
Macular sacculi 球囊斑
End organs of balance, which
respond to linear acceleration
and deceleration, static of
gravity
Semicircular Ducts 膜半规管

Each duct has a
membranous ampullae
膜壶腹

Containing crista
ampullaris 壶腹嵴,
receptors of balance
that respond to
rotational acceleration
in three different planes
Conduction of Sound
Sound waves
Cochlear nerve
Air-conduction of sound
Bony- conduction of Sound
Sound waves
Skull
Bony labyrinth
Endolymph within cochlear duct
Cochlear nerve
Perilymph
Spinal organ
Internal acoustic Meatus 内耳道


Extends from internal acoustic
pore to fundus of internal
acoustic meatus
Facial, vestibulocochlear
nerves and vessels of
labyrinth pass through the
fundus of internal acoustic
meatus
STRUCTURE OF A MACULA
Macula
Otoliths
“Hairs”
Gelatinous
membrane
Hair
cells
Nerve
fibres
Supporting
cells
FUNCTION OF A MACULA
3. Neural impulse
generated
1. Gelatinous
membrane
pulled
downwards
2. Hairs of hair
cells bend
Gravity
Organs of Dynamic Equilibrium:- The Semicircular
Canals
Rotational head movements detected in ampullae at
base of semicircular canals by specialised receptors
called the CRISTAE AMPULLARES
Main features
• support cells
• receptor hair cells
• overlying membrane - cupula
Movements of the head induce the fluid
in the semicircular canals to move
• cupula + hair cells bent - neural impulse
DYNAMIC EQUILIBRIUM:- LOCATION OF CRISTAE
AMPULLARES
Semicircular
canals
Ampulla
STRUCTURE OF A CRISTA AMPULLARIS
Cupula
Hair
cell
Hair cell
Nerve
fibres