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Ocular Anatomy > EOM innervation > Flashcards

EOM innervation Flashcards

1
Q

Yoke muscles definition

A

Equal and simultaneous innervation

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2
Q

Yoke muscle questions

A

Draw EOM diagram

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3
Q

EOMs muscle to nerve ratio

A

Low muscle fiber to nerve fiber ratio

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4
Q

Pupillary reflex route

A

Retinal gang cell- pretectal nucleus - ew - ciliary ganglion - short ciliary nerves - sphincter

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5
Q

Oculomots - parasympathetic

A

Mitosis

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6
Q

CNIII afferent fibers

A

Propioceptive

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7
Q

Nerves passing through SOF

A 
Throchlear 
Lacrimal 
Frontal 
Abducen
Inferior + sup oculomotor 
Nasociliary 7

Angela tiene la nariz fea, super intelligente obvio

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8
Q

How many oculomotor nucleus do we have

And where are they located

A

R and L

In the midbrain ( within gray matter that surrounds cerebral aqueduct, anterior to superior colliculus

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9
Q

Components of each CNIII nucleus

A

Oculomotor nuclear complex

Parasympathetic nucleus = EW

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10
Q

Input into CNIII nuclei includes

A

Cerebral cortex : motor and sensory

Midbrain nuclei: MLF ( CNIV, CNVI, CNVIII nuclei)
Pretectal nucleus
Supraoculomotor area
Cerebellum

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11
Q

CNIII input motor cortical regions

A

Voluntary horizontal gazes

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12
Q

Saccades

A

FEF

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13
Q

Pursuits

A

Occipitoparietal cortex

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14
Q

CNIII input sensory cortical region

A

Visual cortex for accommodation and visual reflexes ( superior colliculus)

Visual association areas

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15
Q

CNIII CN 4, 6, 8 nuclei input come via

A

MLF

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16
Q

CNIII pretectal nucleus input

A

Light reflex and vertical gazes

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17
Q

CNIII supraoculomotor area input

A

Acc reflex

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18
Q

Each oculomotor nucleus has

A

Medial subnucleus

3 lateral subnuclei

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19
Q

Medial subnucleus of oculomotor controls

A

Contralateral SR

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20
Q

3 lateral subnuclei of oculomotor nucleus controls

A

3 ipsilateral EOMS

IO, IR, MR

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21
Q

Parts of CNIII nucleus

A

Common central nucleus

Then each oculomotor nucleus (L and R ) - has 1 medial subnucleus, and 3 lateral subnuclei

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22
Q

EW receives

A

Corticonuclear fibers for accommodation

Pretectal fibers (midbrain) for pupillary reflexes

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23
Q

Where is EW located

A

Posterior to the main motor nucleus in the midbrain

24
Q

Preganglionic fibers from EW path

A

Synapse in ciliary ganglion- enter short ciliary nerves - sphincter and ciliary muscle- pupil contraction/accommodation

25
Q

Oculomotor nerve emerges from

A

Anterior aspect of midbrain medial to the cerebral peduncles and b/w posterior cerebral and superior cerebellar arteries

26
Q

Oculomotor nerve passes through which arteries

A

Posterior cerebral and superior cerebellar arteries

27
Q

Posterior cerebral artery

Superior cerebellar artery

A

CNIII nerve passes through

28
Q

CNIII progresses anteriorly parallel to

A

Posterior communicating artery

29
Q

Where does CNIII pierce the dura

A

At the level of the posterior chinoid process of the sphenoid bone and runs in the lateral wall of the cavernous sinus superiorly to CNIV

30
Q

Where are the parasympathetic fibers of CNIII located

A

On the surface of the nerve and migrate down towards orbit

31
Q

What’s incorporated into the oculomotor nerve as it progresses anteriorly

A

Sensory branch from ophthalmic

Sympathetic fibers from carotid plexus

32
Q

When does the CNIII nerve divide into sup and inferior

A

When they enter the orbit through SOF/ inside annulus of Zin

33
Q

Superior division of CNIII

A

SR and levator

34
Q

Inferior division of CNIII

A

3 branches for Other CNIII muscles (except SR) MR,IR, IO

and parasympathetic fibers for Ciliary ganglion

35
Q

Where is the nucleus of the trochlear nerve

A

Inferiorly to oculomotor nucleus at the level of inferior colliculus

36
Q

Exit of SO4/ trochlear muscle

A

Leave in posterior direction and decussate before exiting the dorsal aspect of the midbrain

37
Q

Where does the trochlear nerve pierce the dura

A

It goes around the cerebral peduncle and pierces the dura close to the posterior chinois process and enters cavernous sinus

38
Q

Where does trochlear nerve pass through after going along the lateral wall of the cavernous sinus

A

Between CNIII superiorly and ophthalmic nerves inferiorly

39
Q

How does the trochlear nerve enter the orbit

A

It becomes medial to oculomotor nerve and enter orbit through SOF above the tendinous ring

40
Q

Where is the nucleus of abducens nerve located

A

In the pons beneath the floor of the 4th ventricle

41
Q

Where does abducens nerve exit

A

Within the sulcus located between the pons and the medulla

42
Q

Where does the abducens pierce the dura

A

Level of the dorsal of the sella truck a

43
Q

How does CNVI enter the orbit

A

Through SOF between the inferior and superior divisions of CNIII (inside the oculomotor foramen

44
Q

Most frequent CN palsy

A

CNVI

45
Q

Least common CN palsy

A

CNIV

46
Q

EOMs during Graves

A

Thyroid disease

Enlargement of EOM causes defective ocular motility and exothalmus

Proptosis

47
Q

Palsies that cause head tilt

A

6 and 4

48
Q

Do pts experience diplopia during CNIII palsies

A

Yes

49
Q

What happens if pt with CNIII palsy try’s to look down

A

SO would cause it to move inward

50
Q

What happens to pupil during CNIII palsy

A

Mydryasis

51
Q

Opthalmoplegia

A

Paralysis or weakness of EOMS

52
Q

External ophthalmoplegia

A

EOMS affected, ptosis

53
Q

Internal ophthalmoplegia

A

Paresis of ciliary body and mydryasis

54
Q

Nuclear lesion of CNIII

A

Involves contralateral superior rectus muscle

55
Q

What happens when you look nasally with a CNIV palsy

A

Affected eye goes up

56
Q

What does pt experience during CNIV palsy

A

Vertical diplopia

Fixed by tilting head to opposite side of the affected muscle

57
Q

What happens to eye when we have CNVI palsy

A

Eye is turned inward

Ocular Anatomy (7 decks)

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