lucci
Forum Senior
Topics: 35
Posts: 52
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50 ys., male, with bifrontal headache for 3 months, sudden vomiting, bilateral papilledema is diagnosed with brain tumor.
Which of the following signs is NOT localizing ?
a. Hemiplegia
b. homonymous hemianopsia
c. oculomotor nerve (III) paralysis
d. abducent nerve (VI) paralysis (lateral oculomotor muscle)
e. unilateral mydriasis
Thank you!
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| aml
Forum Senior
Topics: 5
Posts: 129
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D-6th nerve most common false localising sign.
Possible explanations:
1) stretching of the nerve in its long intracranial course, or compression against the petrous ligament or the ridge of the petrous temporal bone.
or
2) the sixth nerve emerges straight forward from the brain stem, whereas other
cranial nerves emerge obliquely or transversely, it is more liable to the mechanical effects of backward brain stem displacement by intracranial space occupying lesions.
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| ssrpk
Forum Fanatic
Topics: 154
Posts: 2,819
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also, with rising intracranial pressure, the pressure effects itself cause abducens nerve dysfnction as this is the only nerve tht traverses the cavernous sinus!
answer is D
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| mammyQ
Forum Newbie
Topics: 5
Posts: 24
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"Central nervous system lesions of the abducens nerve tract are localized easily secondary to the typical findings associated with each kind of lesion. Damage to the sixth...." Got this from the web page eMedicine.
Why not unilat. Mydriasis?
Please reply.
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