Vestibulocochlear Organ SHANDONG UNIVERSITY Liu Zhiyu The Vestibulocochlear
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
External ear 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 鼓膜脐 Cone of light
Middle ear Consists of three parts n Tympanic cavity n Auditory tube n Mastoid antrum and mastoid cells
Tympanic cavity n 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.
Middle ear n Boundaries: (1) Roof or tegmental wall: (2) inferior wall or jugular wall: separates the cavity from superior bulb of internal jugular v.
Tympanic cavity (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
Middle ear (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 Prominence of facial canal
Middle ear 2. Aditory tube : Bony part : posterolateral 1/3 , open into the anterior wall of tympanic cavity Cartilaginous part : anteromedial 2/3, open into the nasopharynx In childhood: shorter, wider and more horizontal than in adult
Middle ear 3. Mastoid antrum and mastoid cells
Middle ear 2）content of tympanic cavity (1)auditory ossicles： 3 malleus incus stapes （2） tensor tympani stapedius
Internal ear Position: lies in the petrous part of the temporal bone, and consists of two parts: bony labyrinth membranous labyrinth
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 Scala vestibuli Scala tympani Modiolus Osseous spiral lamina
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 the posterior wall 5 opennings of emicircular canals. On its anterior wall, a large opening communicates with the scale vestibuli of cochlea.
bony labyrinth (3) Bony semicircular canals: three in number, the ant. , post. , and lateral simple bony crus ampullar bony crura bony ampulla common bony crus Posterior semicircular canal Lateral semicircular canal Anterior semicircular canal
2. Membranous labyrinth (1) Cochlear duct : in cochlear spiral canal (2) Utricle and saccule: in vestibule (3) Semicircular ducts:
2. Membranous labyrinth 膜迷路 (1) Cochlear duct : superior wall : vestibular wall inferior wall : tympanic wall or basilar membrane spiral organ （Corti） lateral wall:
Membranous labyrinth (2) Utricle and saccule: Connected to each other by utriclosaccular duct receptors of balance, respond to macular utricli linear acceleration and deceleration macular sacculi
Semicircular ducts Cochlear duct saccule Utricle
Membranous labyrinth (3) Semicircular ducts : membranous ampullae crista ampullaris ： 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： the sound wave the external acoustic meatus tympanic membrane fenestra vestibuli chain of auditory ossicles perilymph within the scala vestibuli endolymph within cochlear duct nerve impulse vestibulocochlear n. spiral organ brain
The summary Bony labyrinth: Membranous Abyrinth ： Bony semicircular canals Semicircular ducts Receptors： crista ampullaris Vestibule Utricle、saccule Macular utricli Receptors of balance Macular sacculi Cochlear duct spiral organ Receptor of hearing
Cochlear n. Facial n. Veastibular n.
Fenestra vestibuli Prominence of facial canal Pyramidal eminence Promontory Fenestra cochleae
Conduction of sound External ear Tympanic membrane chain of auditory ossicles fenestra vestibuli Internal ear spiral organ cochlear n.
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