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18 Cards in this Set
- Front
- Back
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strabismus
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two eyes not directed at same point
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diplopia
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double vision
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nystagmus
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oscillatory conjugate eye movements
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extraocular nuclei
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3, 4, 6
GSE LMNs exclusively efferent |
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abducens nucleus
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GSE to ipsilateral lateral rectus muscle
abducens internuclear neurons AINs - axons ascend in contralateral MLF to synapse in the oculomotor complex on LMNs that innervate medial rectus |
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lesion of CN 6
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paralysis of LR muscle
ipsilateral eye is adducted horizontal diplopia gaze to side opposite lesion is unaffected |
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lesion of abducens nucleus
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destroys abducens LMNs and AINs
both eyes deviate to left (right lesion) both eyes point to midpoint in attempted right gaze |
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MLF syndrome
internuclear opthalmoplegia |
lesion in MLF rostral to abducens nucleus
destroys AINs paresis of ocular adduction, horizontal diplopia monocular horizontal nystagmus opposite lesion (good eye looking for bad one) |
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superior oblique
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intorts, depresses, and slightly abducts pupil
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unilateral lesion of CN4
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oblique diplopia
affected eye is elevated, extorted and adducted children tilt heads to side opposite lesion - elicits VOR to intort normal eye to line up with extorted affected eye. |
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unilateral lesion of trochlear nucleus
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very rare
same clinical signs - on contralateral side |
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OMC
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GSE to ocular muscles
GVE - neurons in EW nuclei, synapse in ciliary ganglia - make lens rounder and constrict pupils |
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lesion of CN 3
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ipsilateral eye immobile
extreme abducted and downward position (LR, SO muscles in tact) ptosis pupil fully dilated (anisocoria) direct and consensual pupillary light reflex absent in affected eye |
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vestibular nuclei
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mediate VOR
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vestibulocerebellum
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suppresses VOR to track object by moving head
participates in smooth pursuit movements |
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horizontal gaze center
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located in pontine RF near abducens nucleus
mediates saccades to ipsilateral side |
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vertical gaze center
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mediates vertical saccades
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superior colliculus
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cortical command center for voluntary saccades
lesion - disrupts ability to orient to visual stimuli in contralateral half of visual field |
