Cranial nerves 6

Question 1

where is the olfactory tract and bulb found

Answer 1

on the inferior surface of the frontal lobe

Question 2

where does cranial nerve 8 emerge

Answer 2

with cn7 between the cerebellum and the pons

Question 3

where do olfactory nerves arise from

Answer 3

the olfactory bulb and pass through the cribriform plate of the ethmoid to the upper aspect of the nasal cavity

Question 4

what structures pass through the optic foramen

Answer 4

optic nerve, opthalmic branch of the internal carotid to the orbit

Question 5

what structures lie in the internal accoustic meatus

Answer 5

vestibulocochlear nerve, facial nerve and labyrinthine artery (from basilar)

passes from inside the skull to structures of the inner ear

Question 6

what can cause narrowing of the internal accoustic meatus

Answer 6

acoustic neuroma (most common)
mastoiditis
Paget’s disease

Question 7

where do cn 7 and 8 go after emerging from the internal accoustic meatus

Answer 7

pierce the dura to run in the subarachnoid space to reach the medulla in the angle between the cerebellum and the pons

Question 8

where is the internal accoustic meatus

Answer 8

petrous part of the temporal bone of the skull between the posterior cranial fossa and the inner ear
close to the foramen magnum

Question 9

where is the external accoustic meatus

Answer 9

posterior to the condylar process, superior to the styloid process and anterior to the mastoid process

Question 10

what is the effect of tumours in the internal accoustic meatus and cerebello pontine angle

Answer 10

impingement on cn 7 and 8 giving ipsilateral facial signs

Question 11

what is the choroid plexus

Answer 11

a group of cells that produces CSF in the ventricles

ependymal cells

one in each ventricle

Question 12

what structures make up the external ear

Answer 12

auricle, external accousic meatus

Question 13

what structures make up the middle ear

Answer 13

ossicles, tympanic membrane

connection to pharynx via eustacian/auditory/ pharyngotympanic tube

Question 14

what structures make up the inner ear

Answer 14

semi circular canals,

cochlear

Question 15

what structure passes through the stylomastoid foramen

Answer 15

facial

Question 16

what are the three semicircular canals called

Answer 16

anterior, lateral and posterior, at right angles

Question 17

where can the vestibulocochlear apparatus be found on the petrous bone

Answer 17

middle cranial fossa, petrous temporal bone, on a slight elevation on the bone surface caused by the anterior semicircular canal

Question 18

what is the tympanic plate

Answer 18

part of the temporal bone in front of the mastoid process, surrounds the external part of the ear canal
forms the anterior wall, floor and part of the posterior wall of the bony ear canal

Question 19

what is the function of the cochlear and vestibular aqueducts

Answer 19

allows the membranous labyrintheto connect with the subarachnoid space
for reabsorption of peri and endolymph

Question 20

what is the function of the auricle

Answer 20

catch and funnel sound into the EAM

Question 21

name the main parts of the auricle

Answer 21

helix, antihelix, concha, tragus, antitragus, lobule

Question 22

what nerve supplies muscles that can move the position of the auricle

Answer 22

cn 7, facial

Question 23

how long is the EAM

Answer 23

2.5cm

Question 24

what tissue makes up the lateral third of the EAM

Answer 24

cartilage

Question 25

what tissue makes up the medial third of the EAM

Answer 25

bone

Question 26

what tissues line the EAM

Answer 26

skin, hairs, ceruminous glands that secrete ear wax

Question 27

how can the EAM be straightened to facilitate examination of the tympanic membrane

Answer 27

by
pulling the ear
superiorly,
posteriorly and
slightly laterally

Question 28

what is the sensory supply to the auricle

Answer 28

greater auricular nerve (C2 and 3)

facial nerve

lesser occipital (c2 and 3)

auriculotemporal nerve (cnV3)

Question 29

what is the sensory supply of the EAM

Answer 29

auricular branch of vagus

auriculotemporal branch of V3

Question 30

what is the sensory supply to the tympanic membrane and the middle ear

Answer 30

glossopharyngeal 9

Question 31

how is the tympanic membrane held within the temporal bone

Answer 31

by a fibrocartilaginous ring

lies facing downwars and anteriorly

Question 32

what tissues make up the tympanic membrane

Answer 32

skin, facia, mucous membrane

cn9

Question 33

what is the umbo

Answer 33

a rounded protruberance on the tympanic membrane caused by attachment of the tip of the malleus

Question 34

what is the function of the round window

Answer 34

pressure release from the cochlear

Question 35

where is sound tranmitted to after the ossicles

Answer 35

oval window of the cochlear which converts the mechanical impulses to electrical signals

Question 36

which ossicle is in contact with the oval window

Answer 36

stapes

Question 37

in what order do the ossicles lie in

Answer 37

malleus, incus, stapes

Question 38

what is hyperacusis

Answer 38

intolerance to everyday sounds that causes distress