Neurophysiology: spinal cord hemisection: practice question

A Physiology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Physiology · Neurophysiology: spinal cord hemisection

Sample item

A man has a stab injury causing right-sided hemisection of the spinal cord at T10. Which finding is expected?

ALeft-sided spastic weakness of the legBLoss of pain and temperature sensation on the right below the lesionCLoss of pain and temperature sensation on the left below the lesionDLoss of vibration sense on the left leg

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

C. Loss of pain and temperature sensation on the left below the lesion

In Brown-Sequard syndrome the dorsal columns and corticospinal tract are interrupted on the side of the lesion, giving ipsilateral loss of vibration and proprioception and upper motor neuron weakness. Spinothalamic fibres have crossed within a segment or two of entry, so pain and temperature are lost on the opposite side.

Option by option

A. Left-sided spastic weakness of the leg
Weakness is on the same side as the lesion, which is the right.
B. Loss of pain and temperature sensation on the right below the lesion
Pain and temperature are preserved on the lesion side because fibres from that side have crossed.
C. Loss of pain and temperature sensation on the left below the lesion (correct)
Correct. Spinothalamic fibres cross early and are interrupted for the contralateral side.
D. Loss of vibration sense on the left leg
Vibration is lost on the same side, which is the right.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this Physiology question

What is the answer to this Physiology question?

The best answer is C, Loss of pain and temperature sensation on the left below the lesion. In Brown-Sequard syndrome the dorsal columns and corticospinal tract are interrupted on the side of the lesion, giving ipsilateral loss of vibration and proprioception and upper motor neuron weakness.

Why is "Left-sided spastic weakness of the leg" not the answer?

Weakness is on the same side as the lesion, which is the right.

Why is "Loss of pain and temperature sensation on the right below the lesion" not the answer?

Pain and temperature are preserved on the lesion side because fibres from that side have crossed.

Why is "Loss of vibration sense on the left leg" not the answer?

Vibration is lost on the same side, which is the right.

What concept does this question test?

It tests Neurophysiology: spinal cord hemisection in Physiology. Spinothalamic fibres have crossed within a segment or two of entry, so pain and temperature are lost on the opposite side.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Neurophysiology: spinal cord hemisection?

For each system, sketch the key graph (pressure–volume loop, oxygen dissociation curve, nephron handling) and explain it aloud. Then use the flashcards and the other Physiology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.