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Old 02-16-2011
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Question Neuroanatomy Q (Anatomy)

A 42 year old woman comes to the clinic with complaints of vision, she says she has trouble looking to the right and that she must turn her head to the side to help her see. She also complains that the right corner of her mouth is disfigured and that lately she cannot tolerate simple things like watching, cellphones listening to music or the sound of the doorbell ringing. When she is asked to look towards the right neither eyes move and she is diagnosed with lateral gaze palsy. Where is the location of the lesion?

A) Right frontal lobe
B) Medial longitudinal fasciculus
C) Left frontal lobe
D) Right abducens nerve
E) Right abducens nucleus
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Old 02-16-2011
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E- Right abducens nucleus???

This will explain the lateral gaze paralysis but I can't figure out why the disfigurement and hyperacuses as that shows facial nerve involvement.
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Old 02-16-2011
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Default Right Nucleus Of Abducens

VII nevre nucleus is near of VI nucleus. Maybe This is some kind of "Pontine" Syndrome which involves VII and VI nuclei.
It also could be Left Frontal Lobe (Brodmann 8 Area), but VII is invovled and I think lesion is located in Pons.
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Old 02-16-2011
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Arrow E) Right abducens nucleus

My ans is E) Right abducens nucleus

Pt in this qn stem described that he's experiencing an isolated lesions of the VI nerve nucleus, in other word you can say ipsilateral gaze palsy.

Lesion on the brainstem can produce isolated lesions of the VI nerve nucleus. This will not give rise to an isolated VIth neve palsy because paramedian pontine reticular formation fibers pass through the nucleus to the opposite IIIrd nerve nucleus. therefore, a nuclear lesion will give rise to an ipsilateral gaze palsy.

In addition, fibers of the seventh cranial nerve wrap around the VIth nerve nucleus, and, if this is also affected, a VIth nerve palsy with ipsilateral facial palsy will result. In Millard Gubler syndrome, a unilateral softening of the brain tissue arising from obstruction of the blood vessels of the pons involving sixth and seventh cranial nerves and the corticospinal tract, the VIth nerve palsy and ipsilateral facial paresis occur with a contralateral hemiparesis.

Extra

Foville's syndrome can also arise as a result of brainstem lesions which affect Vth, VIth and VIIth cranial nerves.

Hope this will clear your doubt...
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Old 02-16-2011
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woooo that sure does! Thank you!!!
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aktorque was spot on.

The point was to illustrate the relationship between the nucleus of VI and the fact that the CN VII wraps around the nucleus of VI and can be involved in lesions affecting it.
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it is a good question, and in addition to the fact the the VIIth cranial nerve wrap around the VIth nucleus you should also know that the medial longitudinal fasciculus project from the VIth nucleus to the opposite oculomotor nucleus and NOT directly from the paramedian pontine reticular formation.
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