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Old 09-03-2011
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Help PPRF injury !

QUESTION 1 : If the 'Paramedian Pontine Reticular Formation' is injured due to an infarction or whatever..there will definitely be lateral gaze paralysis. BUT WILL THE CONVERGENCE BE INTACT OR NOT?

It is not clear to me wheather PPRF and abducent nucleus are 2 different structures OR are one and the same ?


QUESTION 2 : Right PPRF inured , both eyes will not be able to gaze to the right direction. Left gaze is normal. At rest, both eyes are centrally (normally alligned). DID I GET ANYTHING WRONG, just checking !?:sorry:
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Old 09-04-2011
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somebody ???
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Old 09-04-2011
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Quote:
Originally Posted by hope007 View Post
QUESTION 1 : If the 'Paramedian Pontine Reticular Formation' is injured due to an infarction or whatever..there will definitely be lateral gaze paralysis. BUT WILL THE CONVERGENCE BE INTACT OR NOT?

It is not clear to me wheather PPRF and abducent nucleus are 2 different structures OR are one and the same ?


QUESTION 2 : Right PPRF inured , both eyes will not be able to gaze to the right direction. Left gaze is normal. At rest, both eyes are centrally (normally alligned). DID I GET ANYTHING WRONG, just checking !?:sorry:
ok let me try here. for question 1. i think convergence should be intact.
question 2. you are correct
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Old 09-04-2011
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Question 1
The lesion of PPRF causes lateral gaze palsy and convergence is not intact cause the 2nd order neuron from PPRF also innervates the Occulomoter nucleus of the contraltereal side.So Medial rectus of the contralateral eye will be paralysed leading to loss of convergence.
Rather there will be slow drift to the contralateral side because of the unopposed action of the other PPRF.

They are two different nucleus but situated PPRF is situated near the Abducens nerve nucleus.

Question 2
See the above explanation
there will be a slow drift towards left.
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Old 09-04-2011
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[QUOTE=usmle2011;65994]Question 1
The lesion of PPRF causes lateral gaze palsy and convergence is NOT intact cause the 2nd order neuron from PPRF also innervates the Occulomoter nucleus of the contraltereal side.So Medial rectus of the contralateral eye will be paralysed leading to loss of convergence.
Rather there will be slow drift to the contralateral side because of the unopposed action of the other PPRF.

i still think convergence should be intact coz Convergence has nothing to do with MLF, the reason being in MS pts. they have intranuclear opthalmoplegia, the gaze palsy but their convergence is intact???
correct me if i m wrong.
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Old 09-04-2011
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convergence should be intact because its mediated by 3rd cranial nerve through its EW nuclei ...........which is directly connected pretectal nuclei ......accommodation convergence and pupilary reflex are mediated through this pathway ........NO involvement of MLF
gaze pathways are located above this level....
and both voluntary and involuntary involves MLF.....

Correct me if I am wrong!!!!!!!!
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Old 09-06-2011
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Thanks Guys for correcting me
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Old 09-08-2011
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Thank you all for participating. Now it is much clearer
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