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* Neuro
 #504020  
  sjsmmd - 05/04/10 16:08
 
  A 40 year old man presented with double vision and was found to have normal vertical eye movements.On left lateral gaze, there was absence of adduction of the right eye, and nystagmus in the abducting left eye. This eye movement disorder can be explained by a lesion in the:
A. Left cerebellopontine angle
B. Right parietal area
C. Right medial longitudinal fasciculus
D. Left medial longitudinal fasciculus
E. Left lateral medulla

 
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* Re:Neuro
#2097178
  iqbalian01 - 05/04/10 16:11
 
  c  
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* Re:Neuro
#2097186
  sammy10 - 05/04/10 16:29
 
  CC.  
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* Re:Neuro
#2097194
  usmlee2010 - 05/04/10 16:41
 
  it would be better if anyone of u give a good explaination,,,,,i thought same ans but dont kno Y
plz anyone of both of u sam or iqbaian
 
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* Re:Neuro
#2097195
  sjsmmd - 05/04/10 16:41
 
  anyone can please explain why?
please
 
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* Re:Neuro
#2097201
  usmlee2010 - 05/04/10 16:45
 
  it would be better if anyone of u give a good explaination,,,,,i thought same ans but dont kno Y
plz anyone of both of u sam or iqbalian
 
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* Re:Neuro
#2097212
  sjsmmd - 05/04/10 16:53
 
  nee explanation: is it ipsilat or contralateral?

Answer: c) right medial longitudinal fasciculus. The diagnosis is right internuclear ophthalmoplegia due to a lesion in the right medial longitudinal fasciculus. The likely underlying pathology is multiple sclerosis, other causes of INO include a glioma or vascular lesion.
 
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* Re:Neuro
#2097213
  iqbalian01 - 05/04/10 16:55
 
  the MLF mediates horizontal gaze.
when you look to the left, the left lateral rectus (supplied by CN VI) and the right medial rectus (supplied by CNIII). an intact MLF is required for the medial rectus to adduct on looking to the left. if there is lesion of the MLF on the right side, then the right medial rectus will not be able to adduct the right eye.
 
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* Re:Neuro
#2097214
  usmlee2010 - 05/04/10 17:00
 
  thanks for explaining .
and yes its ipsilateral loss(just checked on net and as iqbalian explained)
 
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* Re:Neuro
#2097217
  sammy10 - 05/04/10 17:06
 
  Frontal eye fild ( Brodman's area 8) is the region that controls the gaze. Fibres from this centre project onto the Pontine Paramedian gaze centre. From the latter, fibres project onto the ipsilateral abducent nucleus and cross to the opposite side and through the MLF connects with the contralateral oculomotor nerve. So a lesion of the MLF is suppose to show up with ipsilateral oculomotor nerve defect.

Now in this case when the patient attempts left gaze, his right oculomotor is failing. That means the right MLF is damaged..
 
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* Re:Neuro
#2097220
  usmlee2010 - 05/04/10 17:09
 
  key point v can memorize is that function of MLF is ''adduction of eye'' or Horizontal gaze of eye.so to find out which side is affcted we can note which eye is not doing adduction.  
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