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Visual System Anatomy > EOMs > Flashcards

EOMs Flashcards

1
Q

henry’s law of equal innervation

A

innervation to the muscles of the two eyes is equal and simultaneous

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2
Q

MR pathway

A

parallel medial orbital wall –> pass through CT pulley –> follows curve of globe

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3
Q

I band

A 
light skeletal muscle
only actin (double helix)
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4
Q

add- muscle

A

muscle is perpendicular, only torsional movement- no vertical

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5
Q

spiral of tillaux

A

based on the closeness of insetion

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6
Q

LR insertion

A

6.9mm from limbus

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7
Q

epimysium

A

holds all of the muscles together connective tissue

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8
Q

what do muscles do for eyes

A
  • stabilize the eye while the other EOMs are working/moving

- ensure that the EOM action that is wanted is the only motion happening

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9
Q

right gaze

A

dexi version

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10
Q

what muscles elevate

A

SR, IO

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11
Q

primary position: SR secondary acton

A

SR secondary: intortion (y axis)

adduction (z axis)

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12
Q

muscle movement: perpendiclar

A

only torsional (y-axis)

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13
Q

primary position: IR primary

A

IR primary: depression (x axis)

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14
Q

SO origin

A

anatomical: lesser wing og sphenoid
effective: trochlea

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15
Q

synergistic/agonist

A

muscles work together to accomplish the same action

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16
Q

OMT- VEM
adducted position
if eye does not elevate

A

IO

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17
Q

SO pathway

A

-anterior through trochlea –> reverse posteriorly to the insertion of the eye –>

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18
Q

movement in primary position

horizontal rectus muscles

A

horizontal rectus muscles only have one action

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19
Q

thyroid eye disease

A

muscles turn red + can be seen on the eye

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20
Q

EOM assessment

A

do cover test to find primary gaze problem

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21
Q

SR innervation

A

superior division of CN3

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22
Q

SO insertion

A

superior, posterior, lateral globe

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23
Q

when do you get pain with retrobulbar ON

A

converging + nasally (MR + SR)

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24
Q

insertion

A

on something that moves; end

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25
Q

antagonist muscles

A

work in opposite direction

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26
Q

what muscles depress

A

IR, SO

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27
Q

depression

A

infraversion

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28
Q

what muscles abduct

A

LR, SO, IO

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29
Q

left gaze

A

levo version

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30
Q

what muscles adduct

A

MR, SR, IR

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31
Q

So angle

A

55

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32
Q

actin

A

thinner fiber, double helix formation, w/in the grooves you find troponin and tropomyosin

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33
Q

H zone

A

contains only myosin

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34
Q

what muscles extort

A

IO, IR

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35
Q

primary position: IR secondary

A

IR secondary: extortion (y-axis)

adduction (z- axis)

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36
Q

primary gaze

A

straight ahead into the distance

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37
Q

myosin

A

thicker protein, composed of all shafts with head on the end- long filament- 2 heads at each end

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38
Q

sarcolemma

A

plasma membrane- surrounds muscle fibers- contains sarcoplasm

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39
Q

primary position: IO primary

A

IO primary: extorsion (y-axis)

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40
Q

origin of the rectus muscles

A

CTR

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41
Q

sarcoplasm

A

cytoplasm

nuclei, ER, muscle fibers- contracts in the muscle

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42
Q

MR innervation

A

inferior division of CN 3

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43
Q

what is the functional origin of the muscles

A

pulley

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44
Q

tertiary position

A

vertical + horizontal gazes

-up and left, right and down

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45
Q

IR origin

A

CTR

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46
Q

IR innervation

A

inferior division of CN3

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47
Q

IO angle

A

51

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48
Q

OMT-VEM
adducted position
if eye does not depress

A

SO

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49
Q

list the closest to farthest insertion of rectus muscles

A

MR, IR, LR, SR

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50
Q

SR insertion

A

-7.7 from limbus

51
Q

OMT- VEM
abducted position
if eye does not depress

52
Q

VEM- adducted position

A

IO + SO are parallel to axis, allowing only vertical movement

53
Q

A band

A

dark band- myosin (entire length); actin

54
Q

OMT- HEM

if eye does not abduct

55
Q

what muscles attach to the dural sheath of the optic nerve

56
Q

orbital layer

A

adjacent to orbit, stabilize –> acts as a muscle pulley, influence movement but doesn’t cause it
-better accuracy

57
Q

what muscle is the biggest and most used (why)

A

medial rectus, most used- converge out eyes alot

58
Q

SR angle

A

23 degree

pull eye up and inward

59
Q

primary position: SO secondary

A

SO secondary: depression (x-axis), abduction (z-axis)

60
Q

what things shorten w/ muscle contraction

A

I band + H zone

61
Q

z line

A

connects; bisects I band - attaches 2 pieces of actin

62
Q

secondary movement: horizontal rectus muscles

A

slight increase in elevation when eye is elevated

slight increase in depression when the eye is depressed

63
Q

abd- muscle

A

muscle is parallel, vertical movement-no torsion

64
Q

in primary position all of the muscles are

A

in balanced state

  • each muscle is exerting just enough effort to keep the eye centered in the orbit
  • if one muscle is not working, the eye will be deviating away from the primary position in the direction of the antagonist muscle
65
Q

park 3 step

2. is the vertical deviation greater in left or right gaze

A

adducted–> oblique muscles

abducted–> rectus muscles

66
Q

x axis

A

horizontal, runs nasal to temporal

67
Q

IR pathway

A

parallels the floor + SR –> through Ct pulley + follow the globe –> IR sheath extends into inferior tarsal plate

68
Q

y axis

A

horizontal, runs anterior to posterior

69
Q

secondary gaze

A

vertical or horizontal gazez

R,L, up, down

70
Q

primary position: IO secondary

A

IO secondary: elevation (x-axis) abduction (z-axis)

71
Q

SR pathway

A

beneath levator muscle- shares a sheath

-parallel the roof –> through CT pulley + follows the globe

72
Q

MR insertion

A

5.5mm from limbus

73
Q

IO pathway

A

medially inferior orbit to lateral globe –> parallel the SO

74
Q

rotation around the x axis
elevation
depression

A

elevation: supraduction
depression: infraduction

75
Q

muscle movement: parallel

A

only vertical (x-axis)

76
Q

perimysium

A

divides muscles into bundles called fascicles

-surrounds each fascicle

77
Q

rotation around the z axis
medially
laterally

A

medially: adduction
laterally: abduction

78
Q

what is the origin of the MR

A
  • CTR

- sheath of ON

79
Q

z axis

A

vertical, superior to inferior

80
Q

primary position: SO primary

A

SO primary: intorsion ( y-axis)

81
Q

origin

A

never moves- start

82
Q

secondary movement: vertical rectus muscles
Abduction:
SR
IR

A

SR: elevate
IR: depress

83
Q

orbital CT pulleys

A

muscles are stabilized to the orbital wall by connective tissue sheaths known as pulleys

84
Q

versions

A

movement of both eyes in the same direction

85
Q

secondary movement: oblique muscles
Adduction:
SO
IO

A

SO: depression
IO: elevation

86
Q

what muscle is the longest + thinnest

87
Q

rotation around the y axis
nasally
temporally

A

nasally: intorsion, incycloration
temporally: extorsion, excyclorotation

88
Q

elevation

A

supraverson

89
Q

OMT- VEM
abducted position
if eye does not elevate

90
Q

LR origin

A

CTR, greater wing of the sphenoid

91
Q

what do tendons merge with and do

A

pierce tenons capsule + merge with scleral fibers

92
Q

SR origin

A

CTR, sheath og ON

93
Q

IO innervation

A

inferior division of CN 3

94
Q

IR angle

A

23 degree, pulls inwards + downwards

95
Q

IO origin

A

maxillary bone

96
Q

primary position: LR contraction

97
Q

secondary movement: vertical rectus muscles
Adduction:
SR
IR

A

SR: intorsion
IR: extorsion

98
Q

both eyes adducted

A

convergence

99
Q

park 3 step

3. is the vertical deviation greater with the right or left head tilt

A

intorsion –> superior muscles

extorsion –> inferior muscles

100
Q

primary position: MR contraction

101
Q

sherrington’s law of reciprocal innervation

A

contraction of one muscle is accompanied by a simultaneous + proportional relaxation of the antagonist muscle

102
Q

secondary movement: oblique muscles
Abduction:
SO
IO

A

SO: intorsion
IO: extorsion

103
Q

SO innervation

104
Q

park 3 step

1. which eye is hyper in primary gaze?

A

hyper eye: IR or SO (not pulling the eye down)

hypo eye: IO or SR (not pulling the eye up)

105
Q

ductions

A

only looking at movements of one eye

106
Q

OMT-HEM

if eye does not adduct

107
Q

LR pathway

A

parallel the lateral orbital wall –> the CT pulley + follows the globe

108
Q

IO insertion

A

inferior, posterior, lateral globe

109
Q

insertion of rectus muscles

A

into the globe; part that moves

-insert into the anterior globe

110
Q

what muscles intort

111
Q

both eyes abducted

A

divergence

112
Q

retrobullbar optic neuritis

A
  • neuritis behind the eye, ON completely normal,
  • pain w/ eye movements
  • converging + nasally (MR + SR)
113
Q

vergences

A

movement of both eyes in opposite directions

114
Q

global layer

A

closest to globe, adjacent to globe, connects to globe, what is actually moving the eye

115
Q

VEM- abducted position

A

IR + SR are parallel, only allowing vertical movement

116
Q

endomysium

A

surrounds individual muscle fibers

117
Q

what are the functions of the pulleys

A
  • change the function of the rectus muscles in tertiary gaze- not straight ahead
  • refine coordination of muscle movements
  • prevents slideslip of rectus muscles when the eye movements to secondary gaze
118
Q

primary position: SR primary + secondary acton

A

SR primary: elevation (x axis)

119
Q

LR innervation

120
Q

EOM characteristics

A

denser blood supply, densely innervated (fine movement, high velocity), EOMs have a layered organization

121
Q

what are the steps of muscle contraction

A
  1. AP (between nerve + muscle)
  2. release Ach @ NMJ
  3. depolarize the sarcolemma
  4. ca2+ released
  5. binds to troponin/tropomyosin on actin
  6. configuration allowing myosin to bind actin (ATP) –>
  7. tilting of myosin head, pulling actin
  8. shortening of muscle (contractino)
  9. I band + H zone
122
Q

yoke muscle

A

the muscles of the two eyes that work together to cause symmetric, binocular eye movements
-looking in the same direction

123
Q

muscle palsy

A

the opposing muscle can sometimes overact with a palsy b/c there is nothing restricting it

Visual System Anatomy (10 decks)

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