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19 Cards in this Set
- Front
- Back
Conjugate VS Convergence Eye Movements
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Conjugate: eyes move in same direction (to right, to left)
Convergence: eyes converge in direction onto midline object |
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Intorsion vs Extorsion
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Intorsion: move top of eye toward nose
Extorsion: move top of eye AWAY from nose |
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Actions of superior oblique vs actions of inferior oblique
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Superior oblique: Depression, Abduction, Intorsion
Inferior oblique: Elevation, abduction, Extorsion |
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How can you clinically test damage to CN IV?
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CN IV innervates superior oblique muscle
Have patient move eyes inward and down, see which eye is weaker |
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What is head tild associated with? Why?
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CN IV palsy
Tilted head corrects diplopia (double vision) via rotating good eye (correction via vestibular system) |
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What cranial nerves does the medial longitudinal fasciulus connect?
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CN III and CN VI
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Beginning with the lateral rectus of the left eye, outline the synapses that occur in order for the right eye to track horizontal motion.
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Lateral rectus synapses on Nucleus of CN VI
Nuc of CN VI crosses midline via Internuclear neurons of MLF Internuclear neurons synapse on Nucleus of CN III Synapses on Medial Rectus of right eye |
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What are the symptoms of MLF Syndrome?
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MLF Syndrome = Internuclear Ophthalmoplegia
Symptoms: 1) Failure to ADDuct on side of lzn 2) Nystagmus in ABducting eye 3) convergence preserved (rules out CN III lezion) |
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What is One and a Half Syndrome? Symptoms?
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interrupts CN VI in one eye and bilateral internuclear ophthalmoplegia
Symptoms: 1) No ABduction on side of lesion 2) No ADDuction on side of lzn and on opposite side too |
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What are the non-ocular symptoms of MLF syndrome?
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Spasticity
Babinsky Sign Aphasia (Homonymous Hemianopia: loss of one side of visual field; same side in both sides) |
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What is a saccade? When is it used?
Brain regions involved? |
Quick eye movement
Used during reading; eye jumps between points (moves image across retina) Involves vestibular nucleus and cerebellum |
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What is smooth pursuit? When is used?
Brian regions involved? |
Slow eye movement
Fixes an image on retina (fovea?); REQUIRES a visual target (ex: watch an airplane move across sky) Sup colliculus, reticular formation of pons and midbrain |
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What is the vestibulo-ocular reflex? Input required?
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Reflex that stabilized retinal image despite movements of the head
Doesn't require visual input, solely vestibular input |
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What are optokinetic movements? Input requirements?
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Optokinetic movmts:
Slowly move eyes with target, then reset to next target (quick movmt = optokinetic nystagmus) Requires visual input |
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What kind of eye movement is the reticular formation important for?
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Vertical eye movements (sup/inf rectus, and obliques; CN III/IV with nuc in MIDBRAIN)
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What is Parinaud's Syndrome? Symptoms?
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Parinaud's = paralysis of upward gaze (can't look upward)
Symptom: spontaneous vertical nystagmus |
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How could you clinically rule out a bilateral CN III lesion?
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Hold patient's eyelids up, ask to close eyelids
If eyes move upward, CN III intact |
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Symptoms of a CN III palsy?
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Ptosis
Mydriasis (dilated pupil) |
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What is the ocular effect of a cortical lesion?
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Tonic deviation of the eyes toward side of lesion
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