Ear and Temporal Bone

Which structures of the temporal bone comprise the ear?

tympanic and petrous portions

What are the three basic structure of the outer ear?

pinna
external acoustic meatus
tympanic membrane

What separates the middle and outer ear?

tympanic membrane

What are the structures of the middle ear?

- ossicles: malleus, incus, stapes
- auditory/eustachian tube
- stapedius, tensor tympani
- oval window/round window
- chorda tympani
- tympanic plexus

What separates the middle ear from the outer ear?

tympanic membrane

What separates the middle ear from the inner ear?

oval and round windows

What is the function of the ossicles?

amplify sound vibrations (on tympanic membrane) into fluid pressure waves (in the cochlea)

What does the malleus contact?

tympanic membrane

What does the stapes contact?

oval window

What is the function of the oval window?

transmit sound vibrations into cochlea

What is the function of the round window?

compensate changes in pressure

What is the function of the auditory/Eustachian tube?

equalize pressure on either side of tympanic membrane

What is Ottis media?

middle ear infection (treated with tubes)

Where does the tensor tympani attach?

malleus

Where does the stapedius attach?

stapes

What is the function of the tensor tympani and stapedius?

dampen amount of sound conveyed to cochlea by reducing vibration of ossicles

What connects the mastoid air cells to the tympanic cavity?

aditus antrum

What is the chorda tympani?

Branch of a facial nerve

What is the function of the chorda tympani?

1. pass through middle ear
2. enter infratemporal fossa
3. join lingual n. (branch of V3)

What is the tympanic plexus?

VII, IX, X - innervation to mucosa of the inner ear

What is the entrance of the stapedius?

pyramid

What are the structures of the inner ear?

cochlea
semicircular canals
CN VII
CN VIII
internal acoustic meatus

What do the utricle and saccule control?

linear motion

What do the semicircular canals control?

rotational motion

What is the location of the cochlea, vestibule, and canals?

petrous portion of temporal

What is the pathway of sound processing?

1. air wave (external)
2. vibration (middle)
3. fluid wave (inner)
4. impulse