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  #1  
Old 05-23-2013
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Neuro Neuroanatomy tract lesion

61 year old man has had weakness of left leg for 6 months. Examination shows increased muscle tone and reflexes in left lower extremity and an extensor plantar response on the left. Which of the following labeled site on spinal cord is most likely damaged?

A. Right dorsal column
B. Right posterior dorsal horn
C. Right lateral cortical spinal tract
D. Right lateral spinothalamic tract
E. Right anterior ventral horn
F. Left anterior ventral horn
G. Left lateral spinothalamic tract
H. Left lateral cortical spinal tract
I. Left posterior dorsal horn
J. Left dorsal column

----

Here is my dilemma:

Lateral corticospinal tract: UMN: Ipsilateral spastic paresis w/ pyramidal signs (i.e. babinski signs = upward fanning of the toes) below the lesion

However, in FA...it also states lateral corticospinal tract (descending voluntary movement of contralateral limbs)

So, if if we get a lesion of the lateral corticospinal tract...is the site of the damage ipsilateral or contralateral?

Thank you so much!
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  #2  
Old 05-23-2013
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Maybe first aid is talking about contralateral to the Neurons of the cerebral cortex? However the corticospinal is ipsilateral to the LMNs until the desscusation of them in the medulla. The answer should be left.
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  #3  
Old 05-23-2013
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I believe it would be left lateral corticospinal tract UMN lesion. corticospinal tract decussates at the pyramid (at the caudal medulla). If there was a lesion above this area then it would be CONTRALATERAL. Again anyone please feel free to correct me.
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  #4  
Old 05-23-2013
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Quote:
Originally Posted by haseebkat View Post
I believe it would be left lateral corticospinal tract UMN lesion. corticospinal tract decussates at the pyramid (at the caudal medulla). If there was a lesion above this area then it would be CONTRALATERAL. Again anyone please feel free to correct me.

How will they describe in the questions so we know that "If there was a lesion above this area then it would be CONTRALATERAL"?

Thanks in advance.
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Old 05-23-2013
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Now that i can't answer stick with what's in kaplan, high yield, first aid, and Uworld
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  #6  
Old 05-23-2013
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sorry guys, i disagree. i would have chosen C - right lateral corticospinal tract. here is my reasoning:
-clearly this patient has a lesion in the pyramidal or corticospinal tract
-he has UMN features i.e. extensor plantar response
t/f: the lesion must be UMN, but they are just asking us to label it in the SC picture.

in order for the answer to be left lateral corticospinal tract, i figured he had to have right side weakness.

let me know if my understanding is wrong.

p.s. is this a UW q? can you tell us what the right answer is?
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  #7  
Old 05-23-2013
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@bam200,

I don't have the correct answer to this question.

So, you're saying that the answer should be H. Left lateral cortical spinal tract?

Can you find any source(s) or sample question (s) that support your answer that a damage to the lateral cortical spinal tract will provides a ipsilateral damage?

I want to believe that the answer is H. Left lateral cortical spinal tract...an ipsilateral damage bc....
If you take a look at the Brown-Sequard syndrome in FA...Hemisection of spinal cord findings: 1. Ipsilateral UMN signs (corticospinal tract) below lesion.

I'm still confused after reading both FA & Kaplan and found these notes below:

Lateral corticospinal tract: UMN: Ipsilateral spastic paresis w/ pyramidal signs (i.e. babinski signs = upward fanning of the toes) below the lesion

However, in FA Neurology section (Spinal tract anatomy & functions)...it states lateral corticospinal tract (descending voluntary movement of contralateral limbs)

So, if we get a lesion of the lateral corticospinal tract...is the site of the damage ipsilateral or contralateral?
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  #8  
Old 05-24-2013
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no i said RIGHT corticospinal tract, because it should be CONTRALATERAL weakness (the patient c/o left side weakness right?).

*I feel that the question is not asking you the level of the lesion (i.e. cortex, medulla, etc), but they just want you to understand that the lesion is in the corticospinal tract and want you to identify the tract on the diagram.

please do correct me if i am wrong.

Last edited by bam200; 05-24-2013 at 05:45 AM.
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  #9  
Old 05-24-2013
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Default don't get confused with Brown Sequard b/c

The corticospinal tract crosses at the level of the medulla, and since Brown Sequard - is a hemisection of the SPINAL CORD, it would make sense that it causes ipsilateral weakness (i.e. b/c the fibers have already crossed). But, this patient has no other neurologic deficits, hence I don't think Brown Sequard is even an option.
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Old 05-24-2013
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I think left lateral corticospinl tract.
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  #11  
Old 05-25-2013
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Bam please tell us what resources say this.
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  #12  
Old 06-12-2013
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the answer is C
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Old 06-12-2013
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Guys ...
The answer is very easy .. you don't have to think alot about it .. you are labeling a structure in the Spinal Cord ... It has already crossed .. So it is Left lateral Corticospinal tract .. and yes .. Lateral Corticospinal tract is UMN and it synapse with alpha motor neurons in the anterior horn at the level it innervates the muscle .. the alpha motor neuron is the LMN..
and they are labeled right and left after decussation not before.
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Old 06-13-2013
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dr. mma you are wrong, the signs are present of umn lesion not lmn lesion, and corticospinal tracts dcussate at the medulla so any lesion above the decussation will cause contralateral weakness and anything below ispsilateral but as the questions depics it seems like umn lesion,, you are confusing them with sensory tracts
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Last edited by jugraj; 06-13-2013 at 03:54 PM.
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Old 06-13-2013
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after studying about this extinsively I figured out that its right corticospinal tract as they are showing picture of spinal cord, in spinal cord any injury of corticospinal side will be on the ipsilateral side while if it is above decussation than it will be on the opp side, correct me if I am wrong
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Old 06-13-2013
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Quote:
Originally Posted by jugraj View Post
after studying about this extinsively I figured out that its right corticospinal tract as they are showing picture of spinal cord, in spinal cord any injury of corticospinal side will be on the ipsilateral side while if it is above decussation than it will be on the opp side, correct me if I am wrong

the question describes inc reflexes on the left side ... hypertonicity in the left side .... so if they are showing us the Spinal cord one might assume that they are taking about the injury in the SC .... so the tract has already decussated at the pyramid so the lesion should be at the left corticospinal tract so as to give the ipsilateral signs ...

If the question said anything about the injury to the head and brainstem ... as a car accident or hitting something in the head then we should assume that they are directing us to the braintem injury and then we should chose the right corticospinal tract as a answer ...assuming the tract hasn't decussated
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  #17  
Old 10-14-2016
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Default Tract Explanation

The affected area the patient is getting worried is his weakness of the left leg. The weakness of the leg could also be called problems with balance, footing, slow movement, coordination. That tells your right there the lesion is of motor neurons. Remember also that when neurons reach the anterior ventral horn end they connect with lower motor neurons, well most of them do. Also remember that problems in muscle movement only refer to descendant spinal tract pathway.

The most important motor tract is the corticospinal: it controls voluntary movement of all the body. It divides into two neuronal processes, one is anterior the other is lateral. Anterior corticospinal tract controls voluntary muscles of the trunk (thorax and abdomen), lateral corticospinal tract controls voluntary movement of upper & lower limbs. It if was a problem with movement of the head or neck it is a corticobulbar tract problem. Those are the only two who are involved in voluntary movement, others motor tracts do its job involuntarily.

To explain left leg weakness, you have to know that the right hemisphere of the brain in the motor cortex area gives neuronal proyections that deccusate (cross) the medulla oblongata in what is called the deccusation of the pyramids, this is the place where this neuronal proyection cross to the other side. This is why if a person has an injury above this deccusation, a person would have contralateral loss of movement, if the person has ipsilateral (same side) damage, the damage would occur below the deccusation of the pyramids and must a direct damage to the area.

The inside information i can give you is that if they said stroke of traumatic hit to the head, they mean contralateral and if they don't say nothing at all like this case you must assume that is contralateral because in medical journal they describe that lower limbs movement is contralateral. If it ipsilateral they must tell you if there was an accident beforehand.
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Thanks for the question
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it nust be C
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