Brown Sequard Syndrome - HELP!

[StressedMedStud]

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I had a question -> case -> complete spinal cord hemisection on the LEFT at T10.

Which finding is the patient most likely to exhibit?


A) loss of pain and temp on lower left limb

B) flaccid paralysis of left lower limb

C) hyperactive reflexes in left lower limb


The answer is C b/c this represents UMN lesion.

My question is why cant the answer be A? So I understand spinal hemisection to be equivalent to loss of the left side of the spinal cord. Is that correct?

So if there is loss of left half of spinal cord, then for spinalthalamic tract, lets say pain fibers come into the left side of the spinal cord, it has to synapse in the dorsal horn on the LEFT side then cross then go up the right side of spinal cord.

So wouldnt the answer be A because the synapse occurs on the left side of the spinal cord at dorsal horn and if there is left sided hemisection, then how will pain information from left side of body make it up to the right side of the cortex? So i think the answer should be loss of pain information from left lower limb.

 

[loveoforganic]

You would have loss of pain and temp ipsilateral for 1-2 levels below the lesion, but that's it - you wouldn't be making it to the lower limb. All of that is going to be contralateral (from beyond 1-2 levels below the lesion)

 

[HelpPleaseMD]

in brown sequard you lose pain on the contralateral side cause you cut the ascending pathways after the pain fibers dessicute the anterior white commisure. you will only lose the pain/temp sensation on the left for that specific level.
http://www.google.com/imgres?um=1&h...&ndsp=24&ved=1t:429,r:3,s:0,i:94&tx=68&ty=104

maybe that pick will help.

 

[StressedMedStud]

Maybe I dont understand the questions. I thought the pain information from the left lower extremity first has to enter the left side of the spinal cord, which in this patient is hemisected, so if pain fibers cant even make it in the left side of the spinal cord to go up to the brain, then there is loss of pain sensation from the left lower body.

What am i missing?

 

[thinkenergy]

Pain & Temp enters spinal cord via Lissauer's tract, ascends 2-3 levels before it crosses over to contralateral STT via Anterior commissure.

In the question you have a hemisection on left at T10, which means you are lesioning anterior commissure (as well as left STT), this means pain & temperature on right side from T12 or L1 as well as all levels below that cannot be transmitted, but levels above T12-L1 on right side will be normal.

So A is incorrect.

 

[StressedMedStud]

I get it now !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Thanks everyone!!!!!!!!!!!!!!!!!!!!!!!!!!!!