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III. Binocular Vision > Labs (M1) > Flashcards

Flashcards in Labs (M1) Deck (43):
1

Where is the nucleus for CN VI (and at one level)? 1. What does it innervate? 2.

1. beneath the floor of the fourth ventricle (junction of pons and medulla)
2. ipsilateral LR

2

For Type II Duane's Retraction syndrome is abduction or adduction impaired?

adduction

3

What is the yolked muscle for the superior rectus? 1. Superior oblique? 2

1. inferior oblique
2. inferior rectus

4

What is the position the eye must be in to isolate the vertical action of the obliques?

adducting eye (54deg)

5

What is the ocular muscle layer that has high oxidative enzymes and supports prolonged contraction?

orbital layer

6

What are the signs of Inter-nuclear Ophthalmoplegia?

1. adduction lag
2. may have nystagmus on abduction
3. convergence unaffected

7

Where is the origin of the MR? 1. Insertion? 2. What are the muscle movements (primary to tertiary)? 3

1. annulus of Zinn
2. 5-6mm behind cornea
3. adduction

8

What are the possible paretic muscles for a right hyper deviation (left hypo) that increases in right head tilt?

RSR, RSO, LIO, LIR

9

While covering the paretic eye and doing the H test will the look of the covered eye be an overshoot or undershoot?

undershoot

10

What is the position the eye must be in to isolate the vertical action of the recti?

abducting eye (23deg)

11

For Type I Duane's Retraction syndrome is abduction or adduction impaired? 1. What causes retraction? 2

1. abduction
2. adduction

12

What parts of the brain detect motion?

1. middle superior temporal lobe
2. middle temporal lobe

13

What is the stimulus for a saccade?

target displacement on the retina

14

Where is the nucleus for CN III (and at one level)? 1. What does the inferior bifurcation innervate? 2. Superior bifurcation? 3

1. mesencephalon (superior colliculus)
2. IR, IO, MR, parasympathetic (all ipsilateral)
3. SR, LPS (all ipsilateral)

15

What is a partial paralysis of muscle function called?

paresis

16

What are the possible paretic muscles for a right hyper deviation (left hypo) in primary gaze?

RIR, RSO, LIO, LSR

17

What is the pathway for the left eye when making a saccade to the right?

frontal cortex through the omnipause neurons to the paramedian pontine reticular formation (PPRF) through the MLF to CN III to medial rectus

18

What presents like a RIO palsy but is restrictive in nature? 1. What is used to decide between the two? 2. Is this congenital or acquired? 3

1. Brown's Syndrome
2. ductions (full in non-restrictive) and forced ductions (full in non-restrictive)
3. congenital or traumatic

19

What is the law that states that contraction of an agonist muscle occurs concurrently with the relaxation of the antagonist muscle in the same eye?

Sherrington's law of reciprocal innervation

20

What are the steps for the Park's procedure?

1. determine direction of the vertical deviation in primary gaze
2. determine if vertical is greater in right or left gaze
3. determine if vertical deviation is greater with right or left head tilt

21

What are the eye movements that compensate for head motion and rotations?

vestibular eye movements

22

Where is the origin of the SR? 1. Insertion? 2. What are the muscle movements (primary to tertiary)? 3

1. annulus of Zinn
2. 8mm behind cornea
3. elevation, intorsion, adduction

23

What is the pathway for the left eye when making a vestibular eye movement to the right?

vestibular nuclei to paramedian pontine reticular formation (PPRF) through the MLF to CN III to medial rectus

24

Where is the origin of the IO? 1. Insertion? 2. What are the muscle movements (primary to tertiary)? 3

1. anterior floor of orbit (near lacrimal fossa)
2. posterior globe
3. extorsion, elevation, abduction

25

Where is the origin of the SO? 1. Insertion? 2. What are the muscle movements (primary to tertiary)? 3

1. body of sphenoid (trochlea effectively)
2. posterior globe
3. intorsion, depression, abduction

26

Where is the nucleus for CN IV (and at one level)? 1. What does it innervate? 2.

1. lower mesencephalon (inferior colliculus)
2. contralateral SO

27

What is the pathway for the right eye when making a saccade to the right?

frontal cortex through the omnipause neurons to the paramedian pontine reticular formation (PPRF) to CN VI to the lateral rectus

28

What is a total loss of innervation or muscle function called?

paralysis

29

What are the possible paretic muscles for a right hyper deviation (left hypo) that increases in left gaze?

RIO, RSO, LSR, LIR

30

While covering the normal eye and doing the H test will the look of the covered eye be an overshoot or undershoot?

overshoot

31

What does Inter-nuclear Ophthalmoplegia mimic? 1. What is its etiology? 2

1. partial CN III palsy (MR)
2. MS or vertibrobasilar disease

32

Where is the origin of the LR? 1. Insertion? 2. What are the muscle movements (primary to tertiary)? 3

1. annulus of Zinn
2. 7mm behind cornea
3. abduction

33

Where is the origin of the IR? 1. Insertion? 2. What are the muscle movements (primary to tertiary)? 3

1. annulus of Zinn
2. 6-7mm behind cornea
3. depression, extorsion, adduction

34

What is it called when an ocular muscle is tethered to the globe over more area than just the insertion?

muscle pulleys

35

What could mean either a paralysis or a paresis?

palsy

36

What is the pathway for the right eye when making a vestibular eye movement to the right?

vestibular nuclei to paramedian pontine reticular formation (PPRF) to CN VI to lateral rectus

37

Which cranial nerve exits the brain dorsally?

CN IV

38

What is the ocular muscle disorder in which co-contraction of MR and LR (due to CN VI developing incorrectly) causes retraction of the globe on adduction? 1. Is this congenital or acquired? 2

1. Duane's Retraction syndrome
2. congenital

39

For Type III Duane's Retraction syndrome is abduction or adduction impaired?

both abduction and adduction

40

What type of muscle are ocular muscles?

striated

41

What is the grade given for a 2mm over-action? 1. And 1mm under-action? 2

1. grade 2 (+2)
2. grade 1 (-1)

42

What is the ocular muscle layer that has high glycolytic enzymes and is for twitch movements?

global layer

43

What is the law that states during any eye movement, ocular innervation is such that the magnitude of rotation of the two eyes is equal?

Hering's law of equal innervation