CN III, IV, VI Flashcards Preview

Anatomy > CN III, IV, VI > Flashcards

Flashcards in CN III, IV, VI Deck (31):
1

what do CN III, IV, VI innervate

somatic motor to extraoccular eye muscles

2

all extraoccular eye muscles insert where ?

sclera of the eye

3

what is the function of the superior oblique m. ? inferior oblique m.?

superior oblique - internal rotation
inferior oblique - external rotation

4

what level of the brainstem would you find the occulomotor nucleus

rostral midbrain

5

what level of the brainstem would you find the trochlear nucleus

caudal midbrain

6

what level of the brainstem would you find the abducens nucleus

caudal pons

7

what is the autonomic preganglionic cell body located beside the occulomotor nucleus , and what muscles does it innervate ?

Edinger-Westphal of PNS
-pupillary sphincter
-ciliary muscle for accomodation

8

which muscles does CN III have control over, and of those mm. which one is innervated contralaterally

Superior rectus, medial rectus, inferior rectus, inferior oblique
-superior rectus contralaterally the rest are ipsilateral

9

what would be the autonomic result of an injury to the occulomotor and edingerwestphal nuclei ?

mydriasis - ipsilateral dilated pupil
pupil does not constrict in response to light
can not accomodate for close vision
-happens cuz pupillary constrictor and ciliary mm are dysfunctional

10

any injury to the occulomotor nucleus would result in ?

ipsilateral damage to extraoccular mm. innervated by CN III

11

what is a lateral strabismus and what causes it ?

where an eye deviates laterally, caused by lesion to occulomotor nucleus thus making medial rectus dysfunctional

12

what does CN IV innervate ?

contralateral superior oblique m.

13

which CN nucleus would course through the red nucleus

occulomotor nucleus cuz its in rostral medulla

14

what are the results of a lesion in the CN IV nucleus

-much less noticeable than CN III injury (very mild deficit)
-diplopia when reading or going downstairs
-

15

what is the only CN on the dorsal of the brainstem surface

IV trochlea

16

what does CN VI innervate

ipsilateral lateral rectus

17

what is the result of lesion to CN VI

ipsilateral eye damage causing medial strabismus

18

what is a medail labismus and what causes it

eye is deviated medially b/c of a lesion in the CN VI which innervates lateral rectus

19

what is the MLF and what does it do

Medial longitudinal fasiculus
-coordinates head and specifically eye nuclei for lateral gazing

20

internuclear opthalmoplegia is what ?

paralysis of the eye due to damage b/w nuclei
-removes input from occulomotor nucleus

21

what are the 4 sets of neurons involved in the pupillary light reflex

1 - retinal gangli sends afferent to pretectal nuclei
2 - pretectal nuclei to Edingerwestall nucleus
3- EDW nucleus sends preganglionic PNS fibers to ciliary ganglion
4 - synapse at ciliary ganglion sending postganglionic fibers to contract pupillary sphincter and cilliary m.

22

accomodation for near vision is controlled by what ?

PNS

23

what do the short ciliary nerves do ?

postganglionic PNS fibers to tell pupillary sphincter and ciliary mm to contract

24

in response to accomodation the cisual axis of both eyes tend to converge or diverge ?

converge

25

what muscles of the eye are activated by the SNS

pupilary dilator, levator palpebrae superioris

26

what are the 3 conjugate movements of the eye

scanning - 1 target to another in saccades
tracking - smooth pursuit
compensation - gaze held on object during head movement (vestibulocular reflex)

27

what is a saccade

quick simultaneous movement of eyes

28

what is responsible for horizontal saccades

paramedian pontine reticular formation (PPRF)

29

what is responsible for upward saccades

rostral MLF in midbrain

30

what is responsible for downward saccades

midbrain

31

what saccade is voluntary

left