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20 Cards in this Set
- Front
- Back
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vergent movements |
eyes move in opposite directions e.g. divergent, convergent |
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conjugate movements |
eyes move together |
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saccadic vs smooth eye movements |
saccadic: rapid; moves eyes to a new target; no feedback smooth movement: slow, continuous mvmt, keeps image stable on retina; needs sensory feedback |
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Eye directional movements: adduction vs abduction elevation vs depression intorsion vs extorsion |
adduction: eye moves moves medially abduction: eye moves laterally elevation elevation: upward depression: downward intorsion: top of eye moves medially extorsion: top of eye moves laterally |
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strabismus disorder |
misalignment of eyes |
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diplopia disorder |
double vision |
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nystagmus definition |
oscillatory conjugate movements with smooth and saccadic components - direction is named based on the fast movement |
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abducens nucleus |
- close to midline in front of ventricular system - LMN with axons forming CN VI - innervates lateral rectus - abducens internuclear neurons - project via contralateral MLF to oculomotor nucleus; controls medial rectus |
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abducens nerve lesion |
- lateral rectus muscle doesn't work - horizontal diplopia - ipsilateral eye can't go past the midline - no issues with convergence - no issues looking to the contralateral side |
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- abducens nucleus lesion |
- paralized ipsilateral lateral rectus muscle - paralized contralateral medial rectus muscle - lateral gaze paralysis; ipsilateral lateral eye movement does not work - forced gaze to the contralateral side of the lesion - |
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MLF lesion |
- presenting sign in MS (bilateral) - ipsilateral eye looks laterally - contralateral eye works - ipsilateral eye only goes to midline - monocular nystagmus occurs in contralateral eye - convergence is not affected |
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clinical difference b/w abducens nerve or MLF |
can't abduct = nerve problem (ipsilateral) can't adduct = MLF problem (contralateral) |
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trochlear nucleus |
- innervates contralateral superior oblique muscle - lesions rarely occur - lesion = extorted, up, and in when looking straight ahead; when looking opposite side, ipsilateral eye cannot go down, causing diplopia |
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oculomotor nuclear complex |
- LMNs innervate 5 muscles in orbit (SR, MR, IR, IO, LP) - preganglionic parasympthetics |
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CN III lesion complete |
- complete ptosis = ipsilateral full closure of eye; when lid is opened, pupil is down and out |
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pupillary light reflex |
- normal response = constriction of both pupils - CN III lesion: ipsilateral eye will not constrict |
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superior colliculus |
- makes saccades to contralateral visual field |
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frontal eye field |
- contralateral gaze centers - direct and superior colliculus - voluntary saccades (vertical and contralateral) - lesions = similar to abducens lesion - located in back of frontal lobe |
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posterior parietal field |
- visually guided saccades - located in back of parietal lobe |
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V5 |
- smooth pursuit movements via cerebellum - located in back of temporal lobe, maybe occipital lobe? |
