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  #1  
Old 10-04-2011
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Question lesion at dorsal columns

During a fight, a 32-year-old man is hit on the back of the neck with a chair. A CT scan reveals a bony fragment that penetrated the lateral portion of the dorsal columns. Which of the following functions would most likely be affected by a lesion at this site?
A. Fine motor control of the ipsilateral fingers
B. Motor control of the contralateral foot
C. Sweating of the ipsilateral face
D. Proprioception from the ipsilateral leg
E. Vibratory sense from the ipsilateral arm
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Old 10-04-2011
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E is the answer
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My answer is E
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E is correct.
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Old 10-04-2011
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E. Vibratory sense from the ipsilateral arm
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  #6  
Old 10-04-2011
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Correct Answer

if the lesion is above the T6 then only arm is involved which has its nucleus in cuneate.
there is no gracaclis for DC above t6! SO NO ARM INVOLVEMENT. so yeh EEEEEEE
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The correct answer is E. At this level, the lateral portion of the dorsal columns (funiculus) is comprised of the fasciculus cuneatus. Axons carrying tactile, proprioceptive, and vibratory information from the ipsilateral arm enter the spinal cord via the dorsal root, ascend the cord in the fasciculus cuneatus, and synapse in the nucleus cuneatus of the caudal medulla. Secondary neurons from this nucleus give rise to internal arcuate fibers, which decussate and ascend to the thalamus (ventral posterolateral nucleus, VPL) as the medial lemniscus. Tertiary neurons from the VPL project to the ipsilateral somatosensory cortex. Therefore, damage to the fasciculus cuneatus would result in a deficit in tactile, proprioceptive, and vibratory sense in the ipsilateral arm, because the fibers that carry this information do not cross until they reach the medulla.
Fine motor control of the fingers (choice A) would be carried principally by the ipsilateral lateral corticospinal tract in the lateral funiculus of the cord.
Motor control of the contralateral foot (choice B) is carried by the ipsilateral corticospinal tract in the lateral funiculus of the cord.
Hemianhidrosis (lack of sweating) over half of the face (choice C) could be produced by interruption of sympathetic innervation to the face. The hypothalamospinal tract projects from the hypothalamus to the intermediolateral cell column at levels T-1 to T-2. It descends in the lateral funiculus of the cord. Interruption of this tract results in Horner's syndrome (miosis, ptosis, hemianhidrosis).
Proprioception from the ipsilateral leg (choice D) is carried by the fasciculus gracilis in the medial part of the dorsal columns.
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Old 05-13-2013
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easy , it should b option E
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