The Ear

Question 1

what bone houses the vistibulocochlear apparatus

Answer 1

petrous part of temporal bone

Question 2

what two cranial nerves exit the skull through the internal acoustic meatus

Answer 2

CN VII and VIII

Question 3

what emerges through the stylomastoid foramen

Answer 3

the facial nerve

Question 4

what are the three broad areas of the ear

Answer 4

external
middle
inner

Question 5

what does the tympanic membrane separate

Answer 5

external ear from middle ear

Question 6

what does the pharyngotympanic tube join

Answer 6

the middle ear to the nasopharynx

Question 7

what is the function of the external ear

Answer 7

leads sound waves to tympanic membrane

Question 8

what is the function of the middle ear

Answer 8

contains ossicles which mechanically transmit sound

Question 9

what is the function of the inner ear

Answer 9

contains semi-circular canals and cochlea which convert the mechanical signals to electrical signals carried by CN VIII to the brain

Question 10

what aspect of the external ear does the great auricular nerve supply

Answer 10

the medial surface, back of ear and helix and lobules

Question 11

what part of the external ear does the auriculotemporal nerve supply

Answer 11

tragus and crus

Question 12

what comprises the external acoustic meatus

Answer 12

lateral cartilagenous 1/3 and bony medial 2/3

Question 13

what epithelium is present in the external acoustic meatus

Answer 13

stratified squamous epithelium

Question 14

what glands are present in the external acoustic meatus

Answer 14

ceruminous glands

Question 15

what is the function of the ceruminous glands

Answer 15

secretes earwax to keep foreign bodies away from tympanic membrane

Question 16

what is the tympanic membrane held to the temporal bone by

Answer 16

fibrocartilaginous ring

Question 17

what is the umbo of the tympanic membrane

Answer 17

the peak

Question 18

what is the cone of light

Answer 18

caused by light of the otoscope which is characteristic of a healthy middle ear as there is no fluid accumulation

Question 19

what is the middle ear

Answer 19

air filled chamber in petrous part of temporal bone which contains ossicles and two muscles

Question 20

what two muscles are contained in the middle ear

Answer 20

tensor tympani and stapedius

Question 21

what are ossicles

Answer 21

chain of mobile small bones

Question 22

what is the maleus attached to

Answer 22

tympanic membrane

Question 23

what are the three ossicles

Answer 23

maleus
incus
stapes

Question 24

what is the structure of the stapes

Answer 24

kind of looks like a ring

Question 25

what is the function of the ossicles

Answer 25

to increase force and decrease amplitude of vibrations from tympanic membrane

Question 26

what is the function of the tensor tympani

Answer 26

dampens movement of tympanic membrane to protect ear from loud sounds

Question 27

what is the function of the stapedius

Answer 27

dampens or resists movement of ossicles

Question 28

innervation of tensor tympani

Answer 28

CN V3

Question 29

innervation of stapedius

Answer 29

CN VII

Question 30

what is the function of the auditory tube

Answer 30

pressure equalisation between middle ear and atmospheric pressure

Question 31

what is a potential clinical consideration of the internal acoustic meatus

Answer 31

this is where CN VII and VIII exit and there can be a Schwonnoma here which could require surgery

Question 32

what does the CN VII give off when it passes through the middle ear

Answer 32

greater petrosal nerve

Question 33

what is the role of the greater petrosal nerve

Answer 33

carries parasympathetic fibres to pterygopalatine ganglion

Question 34

what nerve is given off just before CN VII exits via the stylomastoid foramen

Answer 34

chorda tympani

Question 35

what two blood vessels run proximal to the middle ear

Answer 35

internal carotid artery internal jugular vein

Question 36

where does the chorda tympani travel in relation to the tympanic membrane

Answer 36

travels deep to the upper portion of tympanic membrane

Question 37

what does the mastoid antrum connect

Answer 37

the mastoid process and middle ear

Question 38

what is conductive deafness

Answer 38

where there is an issue with transmission of the sound (mechanically) via the ossicles - NOT the nerve

Question 39

where is the vestibulocochlear organ housed

Answer 39

inner ear

Question 40

what is the bony labyrinth of the inner ear

Answer 40

semi-circular canals, cochlea and vestibule

Question 41

what fluid is contained in the bony labyrinth

Answer 41

perilymph and endolymph

Question 42

where does the CN VIII split into the vestibular and cochlear parts

Answer 42

after exiting the internal acoustic meatus

Question 43

where does the cochlear part of CN VIII travel to

Answer 43

travels to the cochlea

Question 44

where does the vestibular part of CN VIII travel to

Answer 44

semicircular canals

Question 45

function of cochlear part

Answer 45

hearing

Question 46

function of vestibular part

Answer 46

balance