Vestibulocochlear Organ – -- SHANDONG UNIVERSITY Liu Zhiyu

The Vestibulocochlear Organ Parts: external ear middle ear internal ear Conduct the sound wave 。 Contains the receptors of auditory and vestibular organs

External ear The external ear consists of auricle external acoustic meatus tympanic membrane

External ear 1. Auricle Helix Antihelix crura of antihelix triangular fossa Scapha auricular concha externalacoustic pore Tragus Antitragus auricular lobule

2. external acoustic meatus : bony part ： medial 2/3 cartilaginous part ： lateral 1/3 External ear

3. tympanic membrane : Flaccid part : upper 1/4 Tense part : lower 3/4 Umbo of tympanic membrance Cone of light 鼓膜脐

Consists of three parts Tympanic cavity Auditory tube Mastoid antrum and mastoid cells Middle ear

Position : An irregular air-filled cavity locates within the temporal bone, and lies between the tympanic membrane and the lateral wall of the inner ear. It contains the auditory ossicles, ligaments, muscles, vessels and nerves. Tympanic cavity

Middle ear Boundaries: (1) Roof or tegmental wall: (2) inferior wall or jugular wall: separates the cavity from superior bulb of internal jugular v.

(3) Anterior wall or carotid wall : Upper opening for tensor tympani m. lower opening for auditory tube (4) Posterior wall or mastoid wall: Aditus of mastoid antrum: Pyramidal eminence Tympanic cavity

(5) lateral wall or membranous wall:is formed by tympanic membrane epitympanic recess Middle ear

(6) Medial wall or labyrinthine wall: promontory Fenestra vestibuli Fenestra cochleae : covered by secondary tympanic membrane Middle ear Prominence of facial canal

2. Aditory tube : Middle ear In childhood: shorter, wider and more horizontal than in adult Bony part : posterolateral 1/3,open into the anterior wall of tympanic cavity Cartilaginous part : anteromedial 2/3, open into the nasopharynx

3. Mastoid antrum and mastoid cells Middle ear mastoid cells

2 ） content of tympanic cavity (1)auditory ossicles ： 3 malleus incus stapes Middle ear （ 2 ） tensor tympani stapedius

Internal ear bony labyrinth membranous labyrinth Position : lies in the petrous part of the temporal bone, and consists of two parts:

Internal ear The bony labyrinth is composed of the compact bone, and the latter, a series of communicating membranous sacs and ducts, is contained within the bone labyrinth. The membranous labyrinth is filled with endolymph The space between the membrnous and bony labyrinth is filled with perilymph

bony labyrinth Cochlea Vestibule Bony semicircular canals

bony labyrinth (1) Cochlea : Cochlear spiral canal Modiolus Osseous spiral lamina Scala vestibuli Scala tympani Modiolus Osseous spiral lamina Scala vestibuli Scala tympani

bony labyrinth (2) Vestibule : is the central part of bony labyrinth ， and is medial to the tympanic cavity ， it has 4 walls On its lateral wall fenestra vestibuli fenestra cochleae. The medial wall is the fundus of the internal acoustic meatus

bony labyrinth (2) Vestibule : On its anterior wall, a large opening communicates with the scale vestibuli of cochlea. On the posterior wall 5 opennings of emicircular canals.

bony labyrinth Anterior semicircular canal Posterior semicircular canal Lateral semicircular canal (3) Bony semicircular canals: three in number, the ant., post., and lateral simple bony crus ampullar bony crura bony ampulla common bony crus

2. Membranous labyrinth (1) Cochlear duct : in cochlear spiral canal (2) Utricle and saccule: in vestibule (3) Semicircular ducts:

(1) Cochlear duct : superior wall : vestibular wall inferior wall : tympanic wall or basilar membrane spiral organ （ Corti ） lateral wall: labyrinth 膜迷路 2. Membranous labyrinth

receptors of balance, respond to linear acceleration and deceleration (2) Utricle and saccule : Connected to each other by utriclosaccular duct macular utricli macular sacculi Membranous labyrinth

saccule Utricle Cochlear duct Semicircular ducts

(3) Semicircular ducts : membranous ampullae crista ampullaris ： Membranous labyrinth receptor of balance, which respond to rotation of the head

The Vestibulocochlear Organ Internal acoustic meatus structures passing through it Facial nerve vestibulocochlear nerve vessels of labyrinth

The position of internal ear

Conduction of sound 1 、 Air conductive pathway ： brain tympanic membranechain of auditory ossicles fenestra vestibuliperilymph within the scala vestibuli endolymph within cochlear ductspiral organ nerve impulsevestibulocochlear n. the external acoustic meatusthe sound wave

Receptors of balance Receptor of hearing Bony labyrinth: Bony semicircular canals Vestibule Cochlea Membranous Abyrinth ： Cochlear ductSemicircular ducts Utricle 、 saccule Receptors ： crista ampullaris spiral organ Macular sacculi Macular utricli The summary

前庭阶 鼓阶

Facial n. Veastibular n. Cochlear n.

Fenestra cochleae Promontory Prominence of facial canal Pyramidal eminence Fenestra vestibuli

Conduction of sound External ear Tympanic membrane chain of auditory ossicles fenestra vestibuli Internal ear cochlear n. spiral organ