peripheral distribution of cn i-vi

Question 1

where do cranial nerves 1 and 2 exit from?

Answer 1

the cerebrum

Question 2

where does cn 3 exit from?

Answer 2

midbrain-pontine junction

Question 3

where does cn4 exit?

Answer 3

midbrain

Question 4

where does cn 5 exit?

Answer 4

pons

Question 5

where do 6, 7, 8 exit?

Answer 5

pontine-medullary junction

Question 6

where do 9, 10, 11 exit?

Answer 6

medulla

Question 7

where does 12 exit?

Answer 7

medulla

Question 8

what does the olfactory nerve control?

Answer 8

smell

Question 9

what fibres make up the olfactory nerve?

Answer 9

special sensory afferent

Question 10

where is the FON of the olfactory nerve found?

Answer 10

endothelium of the nose

Question 11

where do the axons of the FON go?

Answer 11

pierce through cribiform plate and into the olfactory bulb where they synapse with mitral cells to form the olfactory tract

Question 12

what is the optic nerve responsible for?

Answer 12

vision

Question 13

what fibres make up the optic nerve?

Answer 13

special sensory afferent

Question 14

what is the optic nerve made up of?

Answer 14

axons of ganglion retinal cells which receive input from the photoreceptors

Question 15

what type of vision are rods responsible for?

Answer 15

low light vision

black and white

Question 16

what type of vision are cones responsible for?

Answer 16

colour vision

Question 17

how are photoreceptors of the eye connected to the visual cortex?

Answer 17

sensory afferents

Question 18

where do the 2 optic nerves connect?

Answer 18

optic chiasm

Question 19

where does the optic tract run?

Answer 19

through the lateral geniculate ganglion in the respective hemisphere

Question 20

how does the optic nerve leave the eyeball?

Answer 20

through the optic canal in the orbit in the sphenoid bone

Question 21

what nerves move the eyeball?

Answer 21

occulomotor
trochlear
abducens

Question 22

what muscles move the eye?

Answer 22

4 rectus muscles
superior oblique
inferior oblique
levator palpabrae superioris

Question 23

where do the rectus muscles originate and where do they attach?

Answer 23

origin - annulus of Zinn

attach - sclera of eyeball

Question 24

what does the levator palpabrae superioris do?

Answer 24

raise the upper eyelid

Question 25

where does the superior oblique originate?

Answer 25

sphenoid bone

Question 26

where does the superior oblique attach and how?

Answer 26

sclera through the trochlea pulley

Question 27

where does the inferior oblique originate and attach?

Answer 27

origin - maxilla bone | attach - sclera (posterior to LR)

Question 28

what is the annulus of zinn?

Answer 28

common tendinous ring at the apex of the orbit in the sphenoid bone

Question 29

what axis do lateral and medial rotation of the eye occur around?

Answer 29

the AP axis

Question 30

what axis do elevation and depression of the eye occur around?

Answer 30

transverse axis

Question 31

what axis do abduction and adduction occur around?

Answer 31

vertical axis

Question 32

what movements does the superior oblique do? which is the main movement?

Answer 32

main: depression intorsion abduction

Question 33

what movements does the inferior oblique do? which is the main movement?

Answer 33

main: elevation extorsion abduction

Question 34

what movements does the medial rectus do?

Answer 34

adduction

Question 35

what movements does the lateral rectus do?

Answer 35

abduction

Question 36

what movements does the superior rectus do?

Answer 36

elevation adduction intorsion

Question 37

what movements does the inferior rectus do?

Answer 37

depression adduction extorsion

Question 38

what fibres make up the occulomotor nerve?

Answer 38

general somatic efferent (GSE), general visceral efferent (GVE)

Question 39

what actions is the GVE responsible for in the occulomotor nerve?

Answer 39

pupil constriction, accommodation reflex (focusing images), pupillary constriction

Question 40

what nucleus gives rise to GSE fibres in the occulomotor nerve?

Answer 40

motor

Question 41

what do the GSE fibres in the occulomotor nerve innervate?

Answer 41

LPS, SR, MR, IR and IO muscles

Question 42

what nucleus gives rise to GVE in the occulomotor nerve and where does the fibre then go?

Answer 42

parasympathetic nucleus | goes to ciliary ganglion then to the sphincter pupillae for constriction and ciliary muscle for accommodation

Question 43

where do sympathetic fibres of the occulomotor nerve come fromand where do they go?

Answer 43

pass through ciliary ganglion from the internal carotid plexus

Question 44

what do the sympathetic fibres of the occulomotor nerve do?

Answer 44

pupil dilation and blood vessel dilation in the eye

Question 45

what fibres make up the trochlear nerve and what do they innervate?

Answer 45

General somatic efferent (GSE) – innervates superior oblique muscle

Question 46

what fibres make up the abducens nerve and what do they innervate?

Answer 46

GSE innervates lateral rectus muscle

Question 47

what shape is the bony orbit?

Answer 47

pyramidal shape

Question 48

how are the medial walls of the orbit orientated?

Answer 48

parallel to each other

Question 49

what angle are the lateral walls of the orbit to each other?

Answer 49

right angles

Question 50

how can a muscle of the eye be tested for a single movement?

Answer 50

Vector pull of the muscle needs to be aligned with the axis of the eye when clinically testing a muscle which carries out more than one movement --> allows muscle to be isolated

Question 51

what are the signs of occulomotor nerve palsy?

Answer 51

``` ptosis stabismus dyplopia dilated pupil down and out - unopposed “down” of superior oblique and “out” of lateral rectus ```

Question 52

what is ptosis?

Answer 52

drooping of the upper eyelid

Question 53

what is stabismus?

Answer 53

eyes not aligned bc the eye starts to pull down

Question 54

what is dyplopia?

Answer 54

double vision

Question 55

what is dilated pupil a sign of occulomotor nerve palsy?

Answer 55

parasympathetic branch of nerve controls constriction of the pupil

Question 56

what causes occulomotor nerve palsy?

Answer 56

Head injury, infection, migraine, brain tumour, aneurysm, diabetes, or high BP

Question 57

what are signs of trochlear nerve palsy?

Answer 57

paralysis of superior oblique eye is elevated, adducted and extorsion patients attempt to minimise diplopia by tilting head

Question 58

what are symptoms of abducens nerve palsy?

Answer 58

paralysis of lateral rectus | affected eye cannot abduct

Question 59

what is abducens nerve palsy a sign of?

Answer 59

raised intracranial pressure

Question 60

what fibres make up the trigeminal nerve?

Answer 60

General somatic afferent, branchiomotor efferent

Question 61

what are the branches of the trigeminal nerve?

Answer 61

v1 - opthalmic v2 - maxillary v3 - mandibular

Question 62

is the opthalmic branch of the trigeminal nerve sensory or motor?

Answer 62

sensory only

Question 63

what are the branches of the opthalmic branch and what do they innervate?

Answer 63

* Lacrimal (doesn’t innervate the gland, just pierces through it), * Frontal (divides into 2 – supertrochlear and superorbital – innervate the upper eyelid and the forehead/skin of the scalp * Nasociliary – sensory supply to the cornea

Question 64

is the maxillary nerve sensory or motor?

Answer 64

sensory only

Question 65

what areas does the maxillary nerve innervate?

Answer 65

Innervates infraorbital, superior alveolar branches (innervates the palate), palatine, zygomatic regions

Question 66

is the mandibular nerve motor or sensory?

Answer 66

both

Question 67

what does the motor branch of the mandibular branch innervate?

Answer 67

Innervates muscles of mastication, ant belly digastric/mylohyoid, tensor tympani, tensor veli palatin

Question 68

what does the sensory branch of the mandibular branch innervate?

Answer 68

buccal (mucous membrane of cheek), auriculotemporal, inferior alveolar, lingual

Question 69

why is there no C1 dermatome?

Answer 69

motor only

Question 70

what causes damage to cranial nerve 5?

Answer 70

Pressure aneurysm, tumour infiltration

Question 71

what are symptoms of cn 5 damage?

Answer 71

- Paralysis muscles of mastication - Loss of sensation to face - Loss of corneal reflex

Question 72

what nerve can a 3rd molar extraction damage and what does this cause?

Answer 72

can damage lingual nerve – loss of sensation to anterior tongue (taste and somatosensory) and reduced salivation due to involvement of the lingual nerve