EOMs Flashcards
(123 cards)
1
Q
henry’s law of equal innervation
A
innervation to the muscles of the two eyes is equal and simultaneous
2
Q
MR pathway
A
parallel medial orbital wall –> pass through CT pulley –> follows curve of globe
3
Q
I band
A
light skeletal muscle only actin (double helix)
4
Q
add- muscle
A
muscle is perpendicular, only torsional movement- no vertical
5
Q
spiral of tillaux
A
based on the closeness of insetion
6
Q
LR insertion
A
6.9mm from limbus
7
Q
epimysium
A
holds all of the muscles together connective tissue
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
9
Q
right gaze
A
dexi version
10
Q
what muscles elevate
A
SR, IO
11
Q
primary position: SR secondary acton
A
SR secondary: intortion (y axis)
adduction (z axis)
12
Q
muscle movement: perpendiclar
A
only torsional (y-axis)
13
Q
primary position: IR primary
A
IR primary: depression (x axis)
14
Q
SO origin
A
anatomical: lesser wing og sphenoid
effective: trochlea
15
Q
synergistic/agonist
A
muscles work together to accomplish the same action
16
Q
OMT- VEM
adducted position
if eye does not elevate
A
IO
17
Q
SO pathway
A
-anterior through trochlea –> reverse posteriorly to the insertion of the eye –>
18
Q
movement in primary position
horizontal rectus muscles
A
horizontal rectus muscles only have one action
19
Q
thyroid eye disease
A
muscles turn red + can be seen on the eye
20
Q
EOM assessment
A
do cover test to find primary gaze problem
21
Q
SR innervation
A
superior division of CN3
22
Q
SO insertion
A
superior, posterior, lateral globe
23
Q
when do you get pain with retrobulbar ON
A
converging + nasally (MR + SR)
24
Q
insertion
A
on something that moves; end
25
antagonist muscles
work in opposite direction
26
what muscles depress
IR, SO
27
depression
infraversion
28
what muscles abduct
LR, SO, IO
29
left gaze
levo version
30
what muscles adduct
MR, SR, IR
31
So angle
55
32
actin
thinner fiber, double helix formation, w/in the grooves you find troponin and tropomyosin
33
H zone
contains only myosin
34
what muscles extort
IO, IR
35
primary position: IR secondary
IR secondary: extortion (y-axis)
| adduction (z- axis)
36
primary gaze
straight ahead into the distance
37
myosin
thicker protein, composed of all shafts with head on the end- long filament- 2 heads at each end
38
sarcolemma
plasma membrane- surrounds muscle fibers- contains sarcoplasm
39
primary position: IO primary
IO primary: extorsion (y-axis)
40
origin of the rectus muscles
CTR
41
sarcoplasm
cytoplasm
| nuclei, ER, muscle fibers- contracts in the muscle
42
MR innervation
inferior division of CN 3
43
what is the functional origin of the muscles
pulley
44
tertiary position
vertical + horizontal gazes
| -up and left, right and down
45
IR origin
CTR
46
IR innervation
inferior division of CN3
47
IO angle
51
48
OMT-VEM
adducted position
if eye does not depress
SO
49
list the closest to farthest insertion of rectus muscles
MR, IR, LR, SR
50
SR insertion
-7.7 from limbus
51
OMT- VEM
abducted position
if eye does not depress
IR
52
VEM- adducted position
IO + SO are parallel to axis, allowing only vertical movement
53
A band
dark band- myosin (entire length); actin
54
OMT- HEM
| if eye does not abduct
LR
55
what muscles attach to the dural sheath of the optic nerve
MR and SR
56
orbital layer
adjacent to orbit, stabilize --> acts as a muscle pulley, influence movement but doesn't cause it
-better accuracy
57
what muscle is the biggest and most used (why)
medial rectus, most used- converge out eyes alot
58
SR angle
23 degree
| pull eye up and inward
59
primary position: SO secondary
SO secondary: depression (x-axis), abduction (z-axis)
60
what things shorten w/ muscle contraction
I band + H zone
61
z line
connects; bisects I band - attaches 2 pieces of actin
62
secondary movement: horizontal rectus muscles
slight increase in elevation when eye is elevated
slight increase in depression when the eye is depressed
63
abd- muscle
muscle is parallel, vertical movement-no torsion
64
in primary position all of the muscles are
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
park 3 step
| 2. is the vertical deviation greater in left or right gaze
adducted--> oblique muscles
| abducted--> rectus muscles
66
x axis
horizontal, runs nasal to temporal
67
IR pathway
parallels the floor + SR --> through Ct pulley + follow the globe --> IR sheath extends into inferior tarsal plate
68
y axis
horizontal, runs anterior to posterior
69
secondary gaze
vertical or horizontal gazez
| R,L, up, down
70
primary position: IO secondary
IO secondary: elevation (x-axis) abduction (z-axis)
71
SR pathway
beneath levator muscle- shares a sheath
| -parallel the roof --> through CT pulley + follows the globe
72
MR insertion
5.5mm from limbus
73
IO pathway
medially inferior orbit to lateral globe --> parallel the SO
74
rotation around the x axis
elevation
depression
elevation: supraduction
depression: infraduction
75
muscle movement: parallel
only vertical (x-axis)
76
perimysium
divides muscles into bundles called fascicles
| -surrounds each fascicle
77
rotation around the z axis
medially
laterally
medially: adduction
laterally: abduction
78
what is the origin of the MR
- CTR
| - sheath of ON
79
z axis
vertical, superior to inferior
80
primary position: SO primary
SO primary: intorsion ( y-axis)
81
origin
never moves- start
82
secondary movement: vertical rectus muscles
Abduction:
SR
IR
SR: elevate
IR: depress
83
orbital CT pulleys
muscles are stabilized to the orbital wall by connective tissue sheaths known as pulleys
84
versions
movement of both eyes in the same direction
85
secondary movement: oblique muscles
Adduction:
SO
IO
SO: depression
IO: elevation
86
what muscle is the longest + thinnest
SO
87
rotation around the y axis
nasally
temporally
nasally: intorsion, incycloration
temporally: extorsion, excyclorotation
88
elevation
supraverson
89
OMT- VEM
abducted position
if eye does not elevate
SR
90
LR origin
CTR, greater wing of the sphenoid
91
what do tendons merge with and do
pierce tenons capsule + merge with scleral fibers
92
SR origin
CTR, sheath og ON
93
IO innervation
inferior division of CN 3
94
IR angle
23 degree, pulls inwards + downwards
95
IO origin
maxillary bone
96
primary position: LR contraction
abduct
97
secondary movement: vertical rectus muscles
Adduction:
SR
IR
SR: intorsion
IR: extorsion
98
both eyes adducted
convergence
99
park 3 step
| 3. is the vertical deviation greater with the right or left head tilt
intorsion --> superior muscles
| extorsion --> inferior muscles
100
primary position: MR contraction
adduct
101
sherrington's law of reciprocal innervation
contraction of one muscle is accompanied by a simultaneous + proportional relaxation of the antagonist muscle
102
secondary movement: oblique muscles
Abduction:
SO
IO
SO: intorsion
IO: extorsion
103
SO innervation
CN 4
104
park 3 step
| 1. which eye is hyper in primary gaze?
hyper eye: IR or SO (not pulling the eye down)
| hypo eye: IO or SR (not pulling the eye up)
105
ductions
only looking at movements of one eye
106
OMT-HEM
| if eye does not adduct
MR
107
LR pathway
parallel the lateral orbital wall --> the CT pulley + follows the globe
108
IO insertion
inferior, posterior, lateral globe
109
insertion of rectus muscles
into the globe; part that moves
| -insert into the anterior globe
110
what muscles intort
SO, SR
111
both eyes abducted
divergence
112
retrobullbar optic neuritis
- neuritis behind the eye, ON completely normal,
- pain w/ eye movements
- converging + nasally (MR + SR)
113
vergences
movement of both eyes in opposite directions
114
global layer
closest to globe, adjacent to globe, connects to globe, what is actually moving the eye
115
VEM- abducted position
IR + SR are parallel, only allowing vertical movement
116
endomysium
surrounds individual muscle fibers
117
what are the functions of the pulleys
- 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
primary position: SR primary + secondary acton
SR primary: elevation (x axis)
119
LR innervation
CN 6
120
EOM characteristics
denser blood supply, densely innervated (fine movement, high velocity), EOMs have a layered organization
121
what are the steps of muscle contraction
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
yoke muscle
the muscles of the two eyes that work together to cause symmetric, binocular eye movements
-looking in the same direction
123
muscle palsy
the opposing muscle can sometimes overact with a palsy b/c there is nothing restricting it
