Eye and Eye movements Flashcards

1
Q

What are the bones of the orbit?

A

St Louis Zoo Makes Entrance Passes Free

Sphenoid

Lacrimal

Zygomatic

Maxillary

Ethmoid

Palatine

Frontal

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2
Q

What passes through the superior orbital fissure?

A

CNs 3, 4, V1, and 6

opthalamic Vs

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3
Q

What passes through the optic canal?

A

optin n

opthalamic A

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4
Q

What passes through the infraorbital fissure?

A

infraorbital A, zygomatic N (branch of maxillary N = V2)

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5
Q

What are the major paranasal sinuses to know?

A

Frontal = sup to orbit

ethmoid = medial to orbit

maxillary = inf to orbit

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6
Q

How do orbital blow out fractures usually occur and what can happen because of them?

A

usually occurs medial and inferiorly involving the maxillary bone (sometimes ethmoid)

blood and other orbital contents can prolapse –> go to maxillary sinus

can get iplopia, globe ptosis, exophthalmos

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7
Q

How is the eye positioned in relation to the orbit?

A

medial walls of orbit are parallel and in line w/ gaze

lateral walls are at right angles

axes of orbit diverge at 45 degree angles

(lateral side of eyeball is more exposed)

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8
Q

What are intorsion and extorsion and upon what axis do they occur?

A

intorsion = medial rotation

extorsion = lateral rotation

on AP axis

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9
Q

What extraocular Ms are innervated by what nerves?

A

SO4 LR6

occulomotor (CN III) –> levator palpebrae superioris, IO, SR, IR, MR

Trochlear N (CN IV) –> superior oblique

Abducent N (6) –> Lateral rectus

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10
Q

What is the action of superior oblique m?

A

(out and down)

abducts

depresses

medially rotates eye

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11
Q

What is the action of inferior oblique m?

A

laterally rotates

elevates

abducts

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12
Q

What occurs to elevation and depression when the eye is abducted by lateral rectus?

A

only rectus ms can produce elevation and depression

(so looking out and up tests SR, looking out and down tests IR)

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13
Q

What happens to elevation and depression during adduction by medial rectus?

A

only the oblique muscles can produce elevation and depression

(looking in and up tests IO, looking in and down tests SO)

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14
Q

What are the branches of V1 (opthalmic n) in the orbit?

A

first breaks into frontal n, nasociliary n, and lacrimal n

lacrimal n –> lacrimal gland

frontal –> supratrochlear and supraorbital n

nasociliary n –> posterior ethmoidal, anterior ethmoidal, infratrochlear, long ciliary, sensory root of ciliary ganglion

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15
Q

What nerves go through both the superior orbital fissure and the common tendinous n?

A

superior and inferior divisions of occulomotor n

nasociliary n (branch of V1)

abducent n (CN 6)

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16
Q

What structures go through the superior orbital fissure but not the common tendinous ring?

A

trochlear n (4)

superior ophthalmic v

frontal n (V1)

lacrimal n (v1)

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17
Q

How do sympathetics get to the eye and what do they innervate?

A

From T1-T4 –> synapse at superior cervical ganglion

postsynaptic fibers –> to internal carotid plexus –> either on CN 3 or V1 –> either to ciliary ganglion and then short ciliary ns

or on their own to muscles via long ciliary n(5) or CN3

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18
Q

What muscles are innervated by sympathetics in the eye?

A

Levator palpebrae superioris m

dilator pupilae

super and inf tarsal muscles

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19
Q

How do parasympathetics travel to and within the orbit?

A

Travel with CN III –> synapse in ciliary ganglion –> short ciliary n to ms

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20
Q

What eye muscles are innervated by PS?

A

sphincter pupilae

ciliary muscle

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21
Q

What types of fibers are in long ciliary nerves?

A

general sensory

post-synaptic sympathetics

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22
Q

What type of fibers are in short ciliary nerves?

A

general sensory

post-synaptic sympathetic

post-synaptic parasympathetic

23
Q

What eye parts are innervated by general sensory fibers?

A

choroid

iris

cornea

24
Q

What occurs in trochlear palsy?

A

Trochlear n innervates superior oblique m (abducts, depresses, medially rotates)

so eye is stuck laterally rotated –> head tilts away from affected side to compensate

diplopia worse on downward gaze

25
Q

What occurs in abducens palsy?

A

CN C innervates lateral rectus m

can’t look laterally w/ affected eye

26
Q

What are the different types of oculomotor palsy?

A

down and out eye: loss of occular m innervation, but SO and LR are still intact (I by 4 and 6)

complete ptosis: loss of I to levator palpebrae superioris m

pupil dilation: loss of PS to pupil

27
Q

What are the 4 steps of the pupillary light reflex?

A
  1. light sensed by CN 2 –> synaps in pretectal nucleus
  2. cells from pretectal nucleus synapse in edinger-westphal nucleus
  3. presyn PS travel w/ CN 3 –> synapse at ciliary ganglion
  4. PS neurons go to pupillary constrictor m
28
Q

What is the corneal reflex?

A
  1. receptors in cornea detect touch –> travel in CN V –> synapse in trigeminal sensory nucleus or spinal trigeminal nucleus
  2. cells from trigeminal nuclei project to facial nucleus
  3. neuron in facial n will cause eye to blink via tarsal m
29
Q

What makes up the fibrous layer of the eye?

A

sclera

cornea

30
Q

What makes up the vascular layer of the eye?

A

choroid

ciliary body

iris

31
Q

What makes up the inner layer of the eye?

A

retina = optic n, covered w/ meninges until it goes in eye

32
Q

What are palpebral and bulbar conjuctiva?

A

palpebral lines innermost part of eyelids

bulbar lines the outermost part of the eyeball

33
Q

What innervates the superior tarsal m?

A

sympathetics

keeps eye open

34
Q

What innervates orbicularis oculi and what does it do?

A

facial N

closes eye

35
Q

What is a subconjunctival hemorrhage?

A

ruptures of vasculature under conjuctiva

see red patches in sclera

36
Q

What are the conjuctival fornices?

A

sac btw bulbar and palpebral conjuctiva

37
Q

What occurs in complete vs partial ptosis?

A

complete = CN3 lesion, levator palpebrae superioris doesn’t work

partial = sympathetics issue that won’t keep eyelid up via Tarsal muscle, usually horner’s syndrome

38
Q

What is papilledema?

A

caused by increased intracranial pressure

see bulging optic disc

39
Q

What is the macula?

What is the fovea?

A

macula = center of vision

fovea = area of macula most concentrated by cones

* have blind spot in optic disc

40
Q

The occlusion of what artery will certainly cause blindness?

A

central retinal artery

quick occlusion of any orbital a –> most likely blindness

slow occlusion –> enough anastomoses that you will be okay

41
Q

What are the 3 main endpoints for venous drainage from the eye?

A

to cavernous sinus

to pterygoid plexus

to facial V and internal jugular

42
Q

What occurs in central retinal vein occlusion?

A

hardening of CRA or HTN can compress –> backup of blood and hemorrhages

dilated veins

looks like ketchup on retina

43
Q

What occurs in central retinal artery occlusion?

A

retina appears white

cherry red spot = macula

veins and arteries attenuated

44
Q

What innervates the lacrimal gland?

A

lacrimal n from CN 5 innervates sensory

PS innervation from greater petrosal n (CN 7)

45
Q

What does the lacrimal part of orbicularis oculi m do?

A

contracts –> opends lacrimal sac to hold more tears

46
Q

What is the general path of tears?

A

lacrimal gland –> to lacrimal canaliculi –> lacrimal sac –> nasolacrimal duct to nose

if tears overflow lacrimal sac –> cry

47
Q

How are tears produced?

A
  1. greater petrosal n (CN 7) and deep petrosal n from n of pterygoid canal
  2. PS fibers synapse in pterygopalantine ganglion
  3. travel w/ V2 then w/ zygomatic branch, communicating branch, then lacrimal n of V1
48
Q

What is the ciliary body?

A

circumferential tissue inside the eye composed of ciliary m and ciliary processes

49
Q

What do ciliary processes do?

A

secrete aqueous humor –> fills ant and post chambers

50
Q

What define the anterior and posterior chambers?

A

part of anterior cavity which is anterior to lens

ant chamber = btw cornea and iris/pupil

post chamber = btw iris/pupil and lens and ciliary body

51
Q

What can glaucoma in relation to aqueous humor?

A

schlemm’s canal = how aqueous humor drains out of anterior cavity of eye

blockage of this canal –> increased pressure = glaucoma

52
Q

What is hyphema?

A

blood pooled btw cornea and iris

53
Q

How do the ciliary ms affect vision?

A

muscles contract –> loosens suspensory L of lens –> lens more round –> near vision

muscles loose –> lens flat –> far vision