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323 - anatomy > lecture 15: CN III, IV, VI > Flashcards

lecture 15: CN III, IV, VI Flashcards

1
Q

true or false and explain: all visual information entering the right eye will end up on the left primary visual cortex

A

false, it is all information from th right visual field

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2
Q

true or false: the right temporal optic radiations carry info from the upper left visual quadrants

A

true

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3
Q

true or false and explain: the temporal aspects of the retina always receive information from the right visual field

A

false, receive info from medial visual fields

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4
Q

true or false and : all neurons carrying information from the fovea (bilateral) will decussate at the optic chaise

A

false

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5
Q

following a head injury, friend says they can barely smell and nose seems runnier than usual (but not congested) what part of olfactory pathway is affected

A

olfactory n (if runny, CSF)
cribirome plate can be broken and damage olfactory nerves

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6
Q

what are the orbits

A

paired pyramidal osseous cavities

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7
Q

what are the 7 bones that contribute to each orgbit

A

frontal
sphenoid
ehhmoid
palatine
lacrimal
maxilla
zygomatic

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8
Q

what fissure is located between the greater and lesser wings of sphenoid

A

superior orbital fissure

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9
Q

explain the oblique orientation of the orbit

A

each apex points in a posteromedial direction, creating an oblique orientation

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10
Q

each apex of orbit points in a BLANK direction, creating an oblique orientation

A

POSTERMOEDIAL

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11
Q

the orbital axis points in what direction

A

posteromedial

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12
Q

true or false, the orbital axis does not equal the optic axis

A

true

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13
Q

explain how the axis of eyeball (optical axis) does not equal the axis of orbit (or=bital axis)

A

orbital axis points posteromedially while optic axis is a straight vertical line

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14
Q

what is at the apex od the orbit

A

optic canal

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15
Q

what n passes thru the optic canal

A

optic n

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16
Q

how many extraocculator muscles are there

A

7

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17
Q

true or false: all 7 extraoccualtor muscles attach to the eye

A

false, only 6

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18
Q

what are the 7 extraoccualar muscles

A

superior obloqie
inferior oblique

medial rectus
lateral rectus
inferior rectus
superior rectus

levator palpeerde superioris

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19
Q

what is the one extraoccular muscle that does not attach to the eyeball

A

levator palpebrae superioris

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20
Q

what are the 3 rotation axes of the extraoccular muscles

A

horizontal (transverse)
vertical
anteroposterior

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21
Q

vertical axis of the eye allows what movements

A

abduction and adduction

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22
Q

anteroposterior axis of the eye allows what movements

A

lateral and medial rotation

aka intorsion and extorsion

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23
Q

tranverse axis of the eye allows what movements

A

evlevation and depression

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24
Q

true or false; eyes usually move along a single plane/single axis

A

false, rarely
extraoccular muscles work in various combos to facilitate muscles

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25
Q

do the rectus muscles attach on the anterior or posterior part of the eyeball

A

anterior

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26
Q

do the oblique muscles attach on the anterior or posterior part of the eyeball

A

posterior

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27
Q

know the locations of the extraocculato eye moments

A
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28
Q

the medial and lateral rectus attach where

A

to common tendinous ring and anterior sclera on medial and lateral sides respective

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29
Q

the medial and lateral rectus only contribute to movement about what axis (and what movements)

A

about the vertical axis (adduction and abduction)

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30
Q

true or false:the medial and lateral rectus only contribute to movement about transverse axis (ie: elevation and depression)

A

false, only vertical axis (adduction and abduction)

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31
Q

what are the only two types of movement possible for the medial and lateral rectus and why

A

only adduction and abduction because they can only contribute to movement about the vertical axis

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32
Q

what os the action of the medial rectus

A

adduction

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33
Q

adduction is medial or lateral erctus

A

medial

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34
Q

what os the action of the lateral rectus

A

abduction

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35
Q

abduction is medial or lateral rectus

A

lateral

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36
Q

is adduction of eye getting closer to further from nose

A

closer

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37
Q

where do the superior and inferior rectus attach

A

to the common tendinous ring and to the anterior sclera on the superior and inferior aspects respectively

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38
Q

the primary action for the superior and inferior rectus is along what axis

A

about the horizontal axis (elevation and depression)

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39
Q

explain the primary, secondary and tertiary actions (along what axes) of the superior and inferior rectus

A

primary action about horizontal axis
secondary action about AP axis
tertiary action about the vertical axis

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40
Q

the secondary action for the superior and inferior rectus is along what axis

A

AP axis (intorsion/extorsion_

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41
Q

the tertiary action for the superior and inferior rectus is along what axis

A

vertical axis (adduction/abduction)

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42
Q

what is the primary action of the superior rectus

A

elevation

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43
Q

what is the secondary action of the superior rectus

A

intersion

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44
Q

what is the tertiary action of the superior rectus

A

adduction

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45
Q

what is the primary action of the inferior rectus

A

depression

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46
Q

what is the secondary action of the inferior rectus

A

extorsion

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47
Q

what is the tertiary action of the inferior rectus

A

adduction

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48
Q

true or false: both thes superior and inferior rectus do adduction

A

true

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49
Q

explain how there is multiracial actions of the superior and inferior rectus muscles

A

can be attributed to the lack of alignment between the optical and orbital axes

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50
Q

true or false: both superior oblique and rectus are abductiors

A

false
superior oblique = abductor
superior rectus=adduction

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51
Q

explain why adduction is a tertiary action for superior and inferior rectus

A

since the medial and lateral rectus are always the primary adductors and abductors

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52
Q

explain attachment of the superior obliqeu

A

attaches to the sphenoid and passes thru a fibrous ring (trochlea) resulting in a change of direction (redirects line of pull)

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53
Q

explain why there is a redirection of line of pull in the superior oblique

A

attaches to the sphenoid and passes thru a fibrous ring (trochlea) resulting in a change of direction (redirects line of pull)

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54
Q

explain the attachment of the inferior oblique

A

attaches to the maxilla on the anterior medial floor of orbit

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55
Q

explain the primary, secondary and tertiary actions (along what axes) of the superior and inferior oblique

A

primary action about the AP axis (torsion)
secondary about the horizontal axis (dep elevation)
tertiary about the vertical axis (adduction/abduction)

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56
Q

the primary action for the superior and inferior oblique is along what axis

A

AP axis (torsion)

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57
Q

the secondary action for the superior and inferior oblique is along what axis

A

horizontal axis (dep and elevation)

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58
Q

the tertiary action for the superior and inferior oblique is along what axis

A

vertical axis (abduction)

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59
Q

what is the primary action of the superior oblique

A

intorsion

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60
Q

what is the secondary action of the superior oblique

A

depression

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61
Q

what is the tertiary action of the superior oblique

A

abduction

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62
Q

what is the primary action of the inferior oblique

A

extorsion

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63
Q

what is the secondary action of the inferior oblique

A

elevation

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64
Q

what is the tertiary action of the inferior oblique

A

abduction

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65
Q

both the superior and inferior obliques are adductors or abducors

A

abductors

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66
Q

both the superior and inferior rectus are adductors or abducors

A

adductors

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67
Q

which extraocculatr muscles do adduction

A

MAIN: medial rectus

side: superior and inferior rectus

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68
Q

which extraocculatr muscles do abduction

A

main: lateral rectus

side: superior and inferrer oblique

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69
Q

which extraocculatr muscles do elevation

A

MAIN: superior rectus

side: inferior oblique

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70
Q

which extraocculatr muscles do depression

A

main: inferior rectus

side: superior oblique

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71
Q

which extraocculatr muscles do intorsion

A

main: superior oblique

side; superior rectus

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72
Q

which extraocculatr muscles do extorsion

A

main: inferior oblique

side: inferior rectus

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73
Q

explain the seemingly inverted actions of the obqlieu muscles about the horizontal axis (ie: superior oblique=depression)

A

can be attributed to how the oblique muscles run anterior to posterior

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74
Q

true or false: the oblique muscles run posterior to anterior

A

false
anterior or posterior

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75
Q

what is the test for extraoccualtor muscles

A

H test

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76
Q

how do you assess the extraoccular muscles (and aosciatdd cranial n)

A

H test

requires isoalated each muscle individually (most movements require multiple muscles)

accomplished by aligning the optical axis with the line of pull for the SR/IF and SO/IO

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77
Q

how can you test the medial and lateral rectus

A

just have them abduct and adduct (since they are the primary movers) and if intact and symmetrical on both sides its good

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78
Q

how can you test the superior and inferior rectus muscles

A

put eye into 23 degrees abduction (produced by lateral rectus) which aligns the optical axis with the line of pull for the superior and inferior rectus muscles

=ask patient to elevate and depression (is only being done by rectus muscles and not obliques)

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79
Q

by putting the eye intoput eye into 23 degrees abduction (produced by lateral rectus), what does this allign

A

which aligns the optical axis with the line of pull for the superior and inferior rectus muscles

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80
Q

if the eye is in 23 degrees abduction, what are the only muscles working for elevation and depression

A

SR and IF

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81
Q

do test SR and IR, does the eye need to be in adduction or abduction

A

abduction

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82
Q

do test SO and IO, does the eye need to be in adduction or abduction

A

adduction

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83
Q

how can you test the superior and inferior oblique muscles

A

put eye into 51 degrees adduction (produced by medial rectus) which aligns the optical axis with the line of pull for the superior and inferior oblique muscles

=ask patient to elevate and depression (is only being done by oblique muscles and not rectus)

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84
Q

by putting the eye intoput eye into 51 degrees adduction (produced by medial rectus), what does this allign

A

aligns the optical axis with the line of pull for the superior and inferior oblique muscles

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85
Q

if the eye is in 51 degrees adduction, what are the only muscles working for elevation and depression

A

inferior and superior oblique

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86
Q

be able to do h test

A
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87
Q

which cranial n is the king of the eyeball

A

oculomotor n (CN III)

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88
Q

what are the 3 cranial n involved in extra occular muscles

A

CN III (oculomotor0
CN IV (trochlear)
CN VI (abducens)

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89
Q

is oculomotor a sensory, motor, or both nerve

A

motor

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90
Q

is trochlear a sensory, motor, or both nerve

A

motor

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91
Q

is abducents a sensory, motor, or both nerve

A

motor

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92
Q

where do all 3 cranial nerves of extra occular muscle innervation (III, IV, VI) exit the skull

A

via the superior orbital fissure

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93
Q

true or false: cranial n III, IV and VI only carry motor info

A

true

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94
Q

what is the only n out of these (trochlear, oculomotor and abducens) that carries visceral motor info

A

oculomotor

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95
Q

what does the superior branch of the oculomotor n innervat

A

SR, levator palp superioris

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96
Q

SR, levator palp superioris are innervated by what

A

superior branch of occulmotor

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97
Q

what does the inferior branch of the oculomotor n innervate

A

IR , MR, IO (preganglionic parasymp fibers)

98
Q

IR , MR, IO (preganglionic parasymp fibers) is innervated by what

A

inferior branch of oculomotor

99
Q

what carries preganglionic parasymp fibers for the eye

A

inferior branch of oculomotor n

100
Q

what carries postganglionic parasymp fibers for the eye

A

short cilliary n

101
Q

what is the parasympathetic ganglion near the eye

A

ciliary ganglion

102
Q

what are the small nerves coming from the ciliary ganglion and what is their function

A

short ciliary nerves

carry post ganglionic parasympathetic fibers (go to our ciliear muscles and scphinter muscles)

103
Q

which nerves carry the postganglionic parasymp fibers for the eye

A

short ciliary n

104
Q

what is the target tissue for the post ganglionic parasympathetic fibers of the eye

A

to ciliary muscles (change the shape of the lens) and sphincter papillae (change the size of the pupil)

105
Q

what does the trochlear n innervate in the eye

A

superior oblique m

106
Q

superior oblique m is innervated by what

A

trochlear n

107
Q

what does the abducens n innervate

A

lateral rectus muscle

108
Q

lateral rectus muscle is innervated by what

A

abducens

109
Q

lesion to abducens n will cause probelms with what movement

A

abduction

110
Q

what is the location of the oculomotor n at the brainstem level

A

interpenduncular fossa (level of superior colliculi)

111
Q

what is the location of the trochlear n

A

dorsal aspect of midbrain (level on inf colliculi)

112
Q

true or false, the trochlear n emerges from ventral brainstem

A

false, dorsal aspect

113
Q

what is the location of the abducens n

A

pontomedullary junco ventrally (most medial)

114
Q

true or false: abducens n carries both somatic and visceral motor info

A

false, oculomotor does

115
Q

oculomotor, abducens and tracheal all emerge from foramina in what skull bone

A

sphenoid

116
Q

true or false: CN III, IV have brainstem nuclei while CN VI does not

A

false, they all are associated with brainstem nuclei

117
Q

why does the oculomotor n have two brainstem nuclei

A

since it carries both visceral and somatic motor info

118
Q

where is the locations of the oculomotor nuclei

A

in rostral midbrain (superior colliculi)
=ventral to cerebral aqueduct near midline)

119
Q

in rostral midbrain (superior colliculi)
=ventral to cerebral aqueduct near midline)

is associated with what brainstem nuclei

A

oculomotor

120
Q

what is the oculomotor nuclei that carries main somatic motor info

A

nucleus of CN III (oculomotor n)

121
Q

what is the oculomotor nuclei that carries visceral motor info

A

accessory oculomotor n

122
Q

true or false: it is almost impossible to damage one oculomotor nucleus without the other

A

true, they are so close

123
Q

what is the location of the trochlear n nucleu

A

caudal midbrain (at inf colliculi)

ventral to cerebral aqueduct

124
Q

caudal midbrain (at inf colliculi)
ventral to cerebral aqueduct

is what brainstem nuclei

A

trochlear

125
Q

true or false: trochlear n comes from the dorsal brainstem

A

true

126
Q

where is the location of the abducens nuclei in the brainstem

A

caudal pons

127
Q

true or false: trochlear n brainstem nuclei is located at caudal pons

A

false, thats abducens

128
Q

what is the somatic motor brainstem nuclei of the trochlear n called

A

nucleus of CN IV/ trochlear nucleus

129
Q

where does the abducens exit the brainstem

A

at the pontomedullary junction

130
Q

true or false: the oculomotor n has the longest intracranial route

A

false, the abducens does

131
Q

in the caudal pons, are the abducens nuclei located more ventral or dorsal

A

dorsal

132
Q

in the caudal pons, are the abducens nuclei located more lateral or medial

A

medial

133
Q

what is the name of the brainstem nuclei for abducens n

A

nucleic of CN VI / abducens nucleus

134
Q

true or false, the right trochlear nucleus gives rise to left trochlear n

A

true

135
Q

are the somatic motor nuclei of CN III, IV, VI located more medial or lateral

A

medial

136
Q

explain the course of the extraoccular muscle n

A

all three n (3,4,6) pass through (or along the wall of) the cavernous sinus en route to the orbit

137
Q

what 3 nerves pass through or along the wall of the cavernous sinus

A

CN III, IV, VI

138
Q

what cranial n passes THROUGH the cavernous sinus out of III, IV, VI

A

abducens (VI)

139
Q

what are some additional structures that pass thru the cavernous sinus (besides CN III, IV, VI)

A

CN V1 and V2, internal carotid a and carotid plexus

140
Q

what sits at the centre of cavernous sinus (but not actually in it)

A

pituitary gland

141
Q

if you have a cavernous sinus hemmorange, what cranial n are affected

A

III, IV, VI

V1 and V2

142
Q

true or false: CN III, IV and VI exit the skull via the inferior orbital fissure of the sphenoid bone

A

false, superior

143
Q

where are the cavernous sinus located

A

lateral to the sella turcica

144
Q

infection of the cavernous sinus that infects cranial n III, IV and VI can lead to what

A

a situation where you no longer have voluntary movement of your eyes

145
Q

true or false: the oculomotor nucleus carries visceral motor

A

false, somatic motor

146
Q

located in the midbrain at the level of the superior colliculi which brainstem nuclei

A

oculomotor n

147
Q

what are the 3 subnuclei of the on=culomotor nucleus

A

lateral
medial
centra

148
Q

what does the lateral sub nucleus or oculomotor supply

A

IPSILATERAL IR, IO, MR

149
Q

IPSILATERAL IR, IO, MR is supplies by what oculomotor sibnucleus

A

lateral

150
Q

what does the medial subnucleus of oculomotor supply

A

CONTRALATERAL SR

151
Q

CONTRALATERAL SR is supplied by what oculomotor subneir

A

medial

152
Q

what does the central sub nucleus of oculomotor supply

A

supplies lev palp superioris bilaterally

153
Q

supplies lev palp superioris bilaterally is done by what oculomotor subnucleus

A

central subnucleus

154
Q

true or false: the central subnucleus of oculomotor supplies lev palp superioris unilaterally

A

false, bilaterally

155
Q

true or false: the right SR will actually be receiving innervation form the right medial subnucleis

A

false, receiving from the left medial subnucleus (since contralateral projections)

156
Q

which is located more dorsal, the oculomotor nucleus or the accessory oculomotor

A

accessory

157
Q

the accessory oculomotor n carries somatic or visceral motor

A

visceral

158
Q

what does the accessory occulomotor nucleus supply

A

ciliary muscles (change in lens shape) and sphincter pupil (constrict pupils) via ciliary ganglion

159
Q

ciliarymuscles (change in lens shape) and sphincter pupil (constrict pupils) via ciliary ganglion is supplied by what brainstem nucelsi

A

accessory occulomotor

160
Q

ciliary muscles (change in lens shape) and sphincter pupil (constrict pupils) are supplied via what ganglio

A

via ciliary ganglion

161
Q

contraction of ciliary muscles increases or decreases internal diameter of the lens

A

decreases (lens becomes fatter)

162
Q

contraction of sphincter pupil constricts or dilates pupil

A

contacts

163
Q

construction of pupil is done by para or sympathetic fibers

A

parasympathetic (via ciliary ganglia)

164
Q

explain sympathetic innervation of dilator pupils

A

comes from thoracic level horns and synapse in superior cervical ganglionsu

165
Q

superior cervical ganglion is for dilating or constricting pupil

A

dilating (sympa)

166
Q

ciliary ganglion is for dilating or constricting pupil

A

constricting (parasympathetic)

167
Q

what are the 3 symptoms of horners syndrome

A

miosis (constricted pupil)
anhidrosis (reduced sweat)
slight ptosis (droopy eyelids)

168
Q

what is miosis

A

constricted pupil

169
Q

what is anhidrosis

A

reduced sweat

170
Q

what is ptosis

A

eyelid drooping

171
Q

miosis, anhydrous and slight ptosis is associated with what condtion

A

horners syndrome

172
Q

horners syndrome is associated with damage to sympathetic or parasympatethic neurons inneravting face and neck

A

sympatethic

173
Q

explain the pathway for horners syndrome

A

higher order, downstream signalling from subcortical structures (eg. hypo)

communicate with preganglionic sympathetic neurons with cell bodies in upper thoracic lateral horns (t1-t2)

preganglionic synapse with posterior ganglionic sympathetic neurons in superior cervical ganglion)

fibers move thru carotid plexus

=innervate the dilator papillae, superior tarsal muscles and eccrine sweat glands

174
Q

in innervation to dilator pupillae, where are the preganglionic sympathetic neurons located

A

cell bodies in lateral horns of upper thoracic area

175
Q

in innervation to dilator pupillae, where do the preganglionic sympathetic neurons synapse with post

A

in superior cervical ganglion (highest region of sympa g=chain)

176
Q

true or false: you can get a droopy eyelid from both parasympathetic and sympathetic damage

A

true just with parasympthieic the affects will be more severe

177
Q

where will the symptoms present in oculomotor n plays

A

all symptoms will present ipsilateral to lesion if the NERVE is affected

178
Q

what are the symptoms of an oclumotor n palsy

A

strabismus (down and out position)
ptosis (droop eyelid)
dilated pupil (decrease sphincter pupil tone)
unresponsive to light and unable to accommodate (loss of ciliary muscle innervation)

179
Q

true or false: all lesions to nerves affected the extraoccualr muscles will result in strabismus

A

true

180
Q

explain why the eye will present in an down and out position for oculomotor n palsy

A

only left with lateral rectors and superior oblique muscles (since they are innervated by trochlear

181
Q

explain why you have a dilated pupil in oculomotor n plasy

A

because there is a decrease sphincter pupilae tone (since innervated by accessory nucleus of oculomotor)

182
Q

explain why you have unresponsiveness to light and unable to accommodate in oculomotor n palsy

A

loss of ciliary n muscle innervation (innervated by accessory oculomotor nucleus)

183
Q

the pupillary light reflex involves what cranial nerves

A

cranial nerves II and II (optic and oculomotor)

184
Q

explain the pathway of the pupillary light reflex

A

stimulus=light

afferent limb (sensory)
=visual info carried by optic n (CN II)
=fibersbypass lateral geniculate nuclei and project to pretectal nuclei in midbrain

interneurons
=pretectal nuclei sends signals to accessory oculomotor nuclei bilaterally (axons decussate in posterior cominssure)

efferent limb (visceral motor)
=preganglionic parasymp fibers from accessory oculomotor nuclei project to the ciliary ganglia (synapse)
=post ganglionic fibers (short ciliary n) innervate sphincter pupillae muscles

response=contrisction of pupils

185
Q

explain the afferent limb aspect of the pupillary light reflex

A

afferent limb (sensory)
=visual info carried by optic n (CN II)
=fibersbypass lateral geniculate nuclei and project to pretectal nuclei in midbrain

186
Q

true or false, in the pupillary light reflex, sensory information carried by optic n will synapse like normal in the lateral genicualte nucleis

A

=fibersbypass lateral geniculate nuclei and project to pretectal nuclei in midbrain

187
Q

where do optic n fibers project to in the pupillary light reflex

A

pretectal nuclei in midbrain

188
Q

explain the interneuron aspect of the pupialry light reflex

A

interneurons
=pretectal nuclei sends signals to accessory oculomotor nuclei bilaterally (axons decussate in posterior cominssure)

189
Q

where do the pretectal nuclei send their signals

A

interneurons
=pretectal nuclei sends signals to accessory oculomotor nuclei bilaterally (axons decussate in posterior cominssure)

190
Q

do pretectal nuclei sends signals to accessory oculomotor nuclei bilaterally or unilaterally

A

bilaterally (axons decussate in posterior cominssure)

191
Q

explain the efferent limb of the pupillary light reflex

A

efferent limb (visceral motor)
=preganglionic parasymp fibers from accessory oculomotor nuclei project to the ciliary ganglia (synapse)
=post ganglionic fibers (short ciliary n) innervate sphincter pupillae muscles

192
Q

where do preganglionic parasymp fibers from accessory oculomotor nuclei project to in the efferent limb of the pupillary light reflex

A

the ciliary ganglia

193
Q

after preganglionic parasymp fibers from accessory oculomotor nuclei project to the ciliary ganglia (synapse), what do the post ganglionic fibers inneravtes in the pupilary light reflex

A

=post ganglionic fibers (short ciliary n) innervate sphincter pupillae muscles

194
Q

what is the response of the pupillary light reflex

A

cosntriction of pupil

195
Q

is there only direct response for the pupilary light reflex and explain

A

no there is direct (eye getting the light) and consensual (other eye not getting light should also constrict)

196
Q

think of a lesion in the pupillary light reflex that would lead to only direct loss, consentual loss or both

A
197
Q

visual accommodation reflex is carried out by what CN

A

CN II and III

198
Q

when does visual accommodation happen

A

when we look at something close and need to keep it in focus on the fovea

199
Q

the visual accommodation response is coordinated by whaat area

A

supraoculomotor area (in upper midbrain at the junction between dienceptaon)

200
Q

what are the 3 main things that happen for viausla accomodation

A

1) convergence of gaze
2) increase in reactive power
3) increase of depth of field

201
Q

explain convergence of gaze in visual accomodation

A

adduction thru activation of medial rectus muscles bilaterallyis

202
Q

is convergence done by medial or lateral rectus

A

medial (it is adduction)

203
Q

explain increase of refractive power in the visual accomodation

A

increase curvature of the lens (get fatter) thru activation of ciliary muscles bilaterally
=to properly land of fovea

204
Q

explain increase depth of field in visual accomodate

A

constriction of pupil through activation of spincther pupilae bilatearlly

205
Q

be able to know visual accomodation pathway

A
206
Q

be able to know the pupillary light reflex plathway

A
207
Q

in trochlear n palsy, will symptoms appear ipsialtearl or contralateral to lesion

A

ipsilateral

208
Q

the trochlear nucleus is somatic motor or visceral motor

A

somatic motor

209
Q

true or false: the trochlear nucleus is locared in the midbrain at the level of the inferior colliculi

A

true

210
Q

what does the trochlear nucleus supply (extraoccular muscle)

A

supplies the superior oblique muscle contra laterally

211
Q

right trochlear nucleus gives rise to the right or left trochelear n

A

left (therefore right trochlear nucleus will supply the left superior oblique)

212
Q

trueor false: lesion to trochlear nerve or trochlear nucleus will result in same symptoms and ipsilateral

A

false, same symptoms but they will be contralateral for the nucleus lesion (since it gives rise so the contralateral n)

213
Q

what are the symptoms of a trochlear n palsy

A

vertical or torsional diplopia (double vision) =torsional axes do not line up

hypertropia (eye deviated upwards)
=compensatory posture is tilting head away from affected side

214
Q

vertical or torsional diplopia (double vision) =torsional axes do not line up

hypertropia (eye deviated upwards)
=compensatory posture is tilting head away from affected side

is associated with what cranial n palsy

A

troclear

215
Q

explain why the eye would be deviated upwards in trochlear n palsy

A

because the superior oblique muscle is damaged (eye cannot go downwards)

216
Q

is the abducens nucleus somatic motor or visceral motor

A

somatic motor

217
Q

true or false: the abducens nucleus supplies the lateral rectus ipsialteral

A

true

218
Q

which nerve has a length intranial course and explain

A

abducens

=travels rostrally in posterior cranial fossa
=sharp right angled bend over apex of petrous temporal bone before enteiring cavernous

219
Q

in abducens n palsy, will the eye be slightly adducted or abducted and why

A

slightly adducted (damaging the innervation to lateral rectus, eye cannot abduct properly)

220
Q

explain what would happen with a left abducens n plays (look right, forward and left)

A

look right: all good
look centre: left eye would be slightly adducted
look left: right eye will look left but left eye (affected) will not move and you will get nystagmus

221
Q

ADD SLIDES ON COORDINATION OF GAZE

A
222
Q

where are the frontal eye fields located

A

in and rostral to supplementary motor area

223
Q

what are the projections of the frontal eye fields in coordination of gaze

A

directly to PPRF (voluntary) and indirectly to PPRF via superior colliculi (reflexive)

224
Q

what are the frontal fields best described as

A

cortical area controlling saccadic eye movements

225
Q

cortical area controlling saccadic eye movements ??

A

frontal eye fields

226
Q

what is blood supply to frontal eye fields

A

middle cerebral

227
Q

what areas are primary associated with smooth pursuit

A

parieto-temporo-occipito areas

228
Q

parieto-temporo-occipito areas are assocaited with smooth pursuit or saccadic

A

smooth

229
Q

explain saccades

A

rapid, coordinated eye movements that redirect gaze to different fixaation points

230
Q

rapid, coordinated eye movements that redirect gaze to different fixaation points

=saccadic or smooth

A

saccadic

231
Q

is saccadic voluntary, reflexive or both

A

both

232
Q

find the target would be saccades or smooth prusit

A

saccades

233
Q

explain smooth pursuit

A

coordinated eye movements that stabilize the image of a moving visual stimuli on the retina

234
Q

coordinated eye movements that stabilize the image of a moving visual stimuli on the retina

is saccades or smooth

A

smooth

235
Q

true or false: smooth pursuit is under voluntary control

A

false, it is not

236
Q

follow teh target is associated with smooth or saccases

A

smooth

237
Q

what is the general somatic function of the oculomotor n

A

innervaties 4/6 extraoccular muscles (not lateral rectus or superior oblique) and lev palp superior

238
Q

what is the general visceral function of the oculomotor n

A

inneravtes ciliary and sphincter pupillae muscles

239
Q

true or false: trochlear n innervates superior rectus m

A

false, superior oblique

240
Q

true or false: abducens n inneravtes the medial rectus muscle

A

false, lateral rectus q

241
Q

explain why you have ptosis in oculomotor n palsy

A

since the oculomotor n (specifically the central subnucleus) innervated the levator palp superioisis

323 - anatomy (18 decks)

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