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Flashcards in cranial nerves Deck (38)
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1

decrease in bilateral constriction when light is shone in affected eye vs unaffected eye is due to

afferent pupillary defect: optic nerve damage or severe retinal injury
called a Marcus Gunn pupil

2

diminshed or no pupillary light reflex in affected eye (direct and consenual) is due to

efferent pupillary defect: CN3 (oculomotor n.) damage due to compression from PCA aneurysm or uncal herniation

3

inner part of CN 3 includes

motor fibers for EOM, levator palpebrae
susceptible to ischemia from diabetes: glucose → sorbitol

4

outer part of CN 3 includes

parasympathetic fibers for pupillary light reflex
susceptible to compression

5

ptosis + down + out gaze due to

ischemia damage to CN3 (inner part of nerve)

6

lateral rectus m. innervated by

CN 6

7

superior oblique m. innervated by

CN 4

8

all the rest of EOM's innervated by

CN 3

9

what is the lesion?
eye looks down + out
ptosis
pupillary dilation
loss of accommodation

CN 3 damage

10

eye looks upward especially with contralateral gaze (problems going down stairs)
head tilt toward side of lesion

CN 4 damage

11

eye looks medially
no abduction

CN 6 damage

12

bitemporal hemianopsia due to lesion at

optic chiasm

13

L or R homononymous hemianopsia due to lesion at

contralateral optic tract

14

L or R anopsia due to lesion at

optic nerve (CN 2)

15

macula lesion due to

macular degeneration

16

L or R homonymous hemianopsia + macular sparing due to lesion at

contralateral PCA infarct

17

nerve that provides touch to anterior 2/3 of tongue

mandibular branch (V3) of CN 5

18

nerve that provides taste to anterior 2/3 of tongue

facial nerve (CN 7)

19

nerve that provides touch to posterior 1/3 of tongue

glossopharyngeal nerve (CN 9)

20

nerve that provides taste to posterior 1/3 of tongue

glossopharyngeal nerve (CN 9)

21

nerve that provides taste to epiglottis

vagus nerve (CN 10)

22

paralysis of ISPSILATERAL side of ENTIRE face caused by this lesion (smile droop + can't close eye)

facial nerve (CN 7)/nucleus lesion (Bell's palsy)

23

paralysis of ISPSILATERAL side of ENTIRE face caused by this lesion

facial nerve (CN 7)/nucleus lesion (Bell's palsy)

24

paralysis of CONTRALATERAL side of LOWER face caused by this lesion

facial motor cortex lesion (stroke)
if able to raise forehead + eyebrows - r/o facial nerve (CN 7) palsy
facial motor cortex receives motor fibers for the LOWER face only from the CONTRALATERAL cortex but receives motor fibers for the UPPER FACE from BOTH cortices

25

CONTRALATERAL uvula deviation due to lesion of

vagus nerve (CN 10) or nucleus ambiguus (medulla lesion)
levator veli palatini m. not elevating the palate on the side of the nerve lesion so uvula deviates in opposite direction (only side pulling up on palate)

26

IPSILATERAL tongue deviation when sticking out due to lesion of

hypoglossal nerve (CN 12)/nucleus
"LICK THE WOUND"

27

IPSILATERAL tongue deviation when sticking out due to lesion of

hypoglossal nerve (CN 12)/nucleus
"LICK THE WOUND" - like a wheelbarrow

28

motor neurons of vagus nerve (CN 10) originate in

nucleus ambiguus in medulla

29

functions of nucleus ambiguus

swallowing + speech + palate elevation

30

nucleus ambiguus in medulla receives input from BOTH motor cortices via corticobulbar tracts

lesion in L or R motor cortex above nucleus ambiguus WON'T cause uvula deviation

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