Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Opt 125: Ocular Motility > Test 1 > Flashcards

Test 1 Flashcards

0
Q

Kraskin-Harmon statement

A

The functional origins of the extra ocular muscles are in the neck and back.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

What is vision?

A

Meaning and direction of action

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why do we have 3-4 gaze redirections per second?

A

The image on the retina fades without movement of the eye.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Integration of action and recognition

A

Action: moving the eyes
Recognition: knowing what you’re looking at

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Signs of optic neuritis:

A

Inflammation of CN2

  • pain during EOMs
  • may be (+)APD if retrobulbar
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

SR origin

A

Superior annulus of Zinn

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

SR insertion

A

Obliquely on superior sclera

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

SR movements

A

Coordinated movements with levator because of shared muscle sheath

23* angle with Fick’s axis to allow for more movement than straight up

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

IR origin

A

Inferior annulus of Zinn

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

IR insertion

A

Oblique arc onto inferior sclera

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

IR movement

A

Suspensory ligament of Lockwood

23* angle with Fick’s Y-axis for more movement than just straight down

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

LR origin

A

Upper and lower limb of annulus of Zinn

Process of greater sphenoid bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

LR insertion

A

Parallel to MR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

LR movement

A

Lateral check ligament for added support

Whitnall’s tubercle for attachment to lateral wall

Rotation about the Z axis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

MR origin

A

Upper and lower Annulus of Zinn

Optic nerve sheath

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

MR insertion

A

Vertical line spanning horizontal plane of eye

Closest muscle to limbus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

MR movement

A

Medial check ligament attaches muscle to medial orbital wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the Spiral of Tilleaux?

A

Spiral around limbus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

SO anatomical origin

A

Lesser sphenoid wing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

SO physiological origin

A

Cartilaginous trochlea, superior medial orbital wall

Muscle ends BEFORE trochlea (muscle tendon passes through though)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

SO insertion

A

Lateral posterior globe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What happens during SO tendon flexion when the eye rotates 36 deg outward and is perpendicular to the deflection tendon?

A

Intorsion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What happens during SO tendon flexion when the eye moves 54 deg inward, matching the line of sight to the tendon angle?

A

Depression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Which is the only EOM to originate in the anterior orbit?

A

The IO

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

IO origin

A

Maxillary bone inferior to nasolacrimal fossa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

IO insertion

A

Posterior-lateral globe, inferiorly

Below anterior-posterior horizontal plane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

The angle the IO has with the visual axis

A

51 deg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Where the center of the muscle or tendon first touches the globe

A

Tangential point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Why is the tangential point not fixed?

A

It moves.

It changes when the muscle contracts or relaxes, and the eye moves.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

The arc formed between the tangential point and the center of the insertion on the sclera

A

Arc of contact

30
Q

Why does the arc of contact vary in length?

A

With muscle contracture, the arc length varies.

31
Q

What is determined by a tangential point and the center of rotation?

A

The muscle plane

32
Q

What does the muscle plane describe and determine?

A

Direction of pull of the muscles

Axis of rotation

33
Q

Strabismus surgery: resection

A

Piece taken out

Make muscle short

34
Q

What type of strabismus surgery fixes exotropia?

A

Resection surgery

35
Q

Strabismus surgery: recession

A

Cut the muscle and move it backwards in hopes of weakening the muscle

36
Q

What type of strabismus surgery fixes esotropia?

A

Recession surgery

37
Q

Strabismus surgery: transposition

A

Changes direction of pull by LR and MR upwards

38
Q

What type of surgery will fix a hyper?

A

Transposition surgery

39
Q

What is field of fixation?

A

Area within which central fixation is possible by moving the eyes ONLY

40
Q

Which field of fixation is larger, binocular or monocular?

A

Monocular because the nose doesn’t get in the way

41
Q

What limits the FOF?

A

Structures around the orbit

Refractive state of the globe

42
Q

What is the reference position for ocular rotation?

A

Primary position

43
Q

What are rotations of a single eye?

A

Ductions

44
Q

What are rotations of both eyes?

A

Versions

45
Q

Rotation of 12:00 towards the nose

A

Intorsion

46
Q

Rotation of 12:00 towards the ear

A

Extorsion

47
Q

Sherrington’s Law of Reciprocal Innervation

A

When a muscle contracts, it’s direct (w/i same eye) antagonist relaxes to an equal extent

Ex. LMR and LLR

48
Q

Herings Law of a Equal Innervation

A

Contraction of one EOM occurs with equal and simultaneous contraction of the the Contralateral agonist

Ex. LIO and RSR

49
Q

Positive forced duction test

A

The eye did not move, so we know there is a muscle or orbit problem

50
Q

Negative duction test

A

The eye moves, so we know there is a nerve, neuromuscular junction, or brain problem.

51
Q

Movement of a body in a 2D direction

A

Translation

Commutative

52
Q

Movementof a body in a 3D direction

A

Rotation

Not commutative

53
Q

Fick’s X axis

A

Pitch

54
Q

Fick’s Y axis

A

Yaw

55
Q

Fick’s Z axis

A

Roll

56
Q

Flat movement

A

End position can be described 3 Cartesian coordinates

Cannot return to original position

57
Q

Curved movement

A

End position cannot be described using 3 coordinates

We can get back to the original position though

58
Q

Ruete and Donders

A

Observed the cross grid with after images and discovered false torsion

59
Q

What is happening with false torsion?

A

A different torsional position of the eye is not actually being achieved. It looks like this because curved space and a flat grid do not match.

60
Q

Donder’s Law

A

Wherever the eye lands, there’s only 1 torsional position for that landing point

Only one orientation can be reached by a single rotation

61
Q

Listing’s Law

A

We can figure out what the orientation that Donders was talking about actually is by measuring rotations around Listing’s Plane

62
Q

Listing’s Plane

A

A theoretical plane through the equator of the globe, separating it into anterior and posterior segments

63
Q

How many sequences of rotation are possible?

A

6

64
Q

Fick’s Eye-Fixed System

A

The vertical z axis is fixed in the skull

65
Q

Helmholtz Eye-Fixed System

A

The horizontal x axis is fixed in the skull

66
Q

Euler’s Head-Fixed System

A

New orientation can be represented by rotation around a single axis at a specific angle relative to the vertical axis

67
Q

Listing’s Law in Helmholtz coordinates

A

T=-HV/2

68
Q

Positive quantities for Listing’s Law

A

Clockwise, right, and up from the patient’s POV

69
Q

Listing’s Half-Angle Rule

A

Whatever the angle measure for the tilt of the LOS is, Listing’s plane is rotated from its usual position by half that angle amount

One-eyed situation
Head at rest

70
Q

Binocular extension of Litsting’s law

A

When the eyes converge, they do so at a tilt from the primary position, angle a. The velocity plane for each eye tilts a fourth of angle a away from the normal Listing Plane

2-eyed situation
Head at rest

71
Q

Half Listing’s Law for VOR

A

During head rotation, velocity plane tilts about 1/3 to 1/4 as the LOS

1-eyed situation
Head in motion

72
Q

What is the only EOM without a pulley?

A

The SO, it has the trochlea

73
Q

Functional origins of EOMs

A

At its pulley

In the neck and back (viewing system as a whole)

Opt 125: Ocular Motility (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions