visual pathway

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visual pathway

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docsrinu
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09/11/06 - 07:34 PM

A 52-year-old man comes to his physician because his wife noticed that his right pupil is "small." Physical examination shows that the right pupil is constricted and does not react to light. His left pupil is normal. These findings are most likely due to a lesion involving which of the following structures on the right?

A) visual cortex
B) Frontal eye fields

C) Lateral geniculate nucleus

D) Optic tract

E) cervical spinal cord

vanshita
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09/11/06 - 07:38 PM

hope99
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09/11/06 - 09:54 PM

mediocre
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09/21/06 - 03:42 PM

please explain your answers.....thanx

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prasanthtalluri
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10/04/06 - 09:05 PM

mediocre wrote:
please explain your answers.....thanx

i think it could be the answer A as it is not reacting to light it could be damage to the optic tract which are the consensual light reflex lesions.

vallia
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10/05/06 - 01:16 PM

E

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young_doc
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10/05/06 - 03:14 PM

prasanthtalluri wrote:

i think it could be the answer A as it is not reacting to light it could be damage to the optic tract which are the consensual light reflex lesions.

If that were true than i don't think it would be constricted under normal conditions?

I think it's E. Or damage to the SANS.

Anyone else?

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Dr.Papez
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10/06/06 - 11:44 AM

Had some discussion on the same topic earlier. Click below.

http://www.prep4usmle.com/forum/comments.php?id=3...

Ig F
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12/08/06 - 01:29 AM

itz E..injury to the sympathetics to pupil cause miosis.........remember cervical spinal cord has sympathetics which result in horners synd.....in which miosis(constricted pupils) r the presentation.......

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mukesh
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02/25/07 - 04:55 AM

#10

I dont think that E is suitable because it may effect on both pupils

Dr.Papez
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03/04/07 - 05:13 PM

#11

how do right side of cervical spinal cord involvement affect both pupils?
Please explain.

babydoc4usmle
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03/05/07 - 06:44 AM

#12

why both? left was normal

indidoc1
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03/05/07 - 08:07 AM

#13

Guys.. i think this is a NBME Q.. Plz indicate that in the topic in future.. PLEASE.. i request u.. sad

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Dr.Papez
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03/05/07 - 06:56 PM

#14

hi baby...!
I am asking Mukesh to explain his comment

babydoc4usmle
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03/07/07 - 05:58 PM

#15

ohh...

lq2006
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05/16/07 - 06:51 PM

#16

cervical spinal cord

Jackofknives
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05/16/07 - 11:46 PM

#17

Dr.Papez wrote:
how do right side of cervical spinal cord involvement affect both pupils?
Please explain.

No mate, lesion to the horner tract in the spinal cord will affect the ipsilateral eye, the innervation is not diffuse. Its basically the same principle that you will get HEMIanhydrosis, one of the symptoms of horner syndrom. Hemi means half, ie one side.

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