Neuroanatomy: central cord syndrome: practice question

A Anatomy 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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Anatomy · Neuroanatomy: central cord syndrome

Sample item

A 68-year-old man with cervical spondylosis hyperextends his neck in a fall and has greater weakness in both arms than legs, with burning hands. Perianal sensation is preserved. What best explains the sparing of sacral function?

AThe sacral roots leave the cord below the level of the injuryBSacral fibres run in the posterior columns, which a central lesion sparesCSacral fibres lie peripherally in the lateral tracts, away from the central lesionDThe sacral cord is supplied by the posterior spinal arteries alone

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

The answer and the reasoning

C. Sacral fibres lie peripherally in the lateral tracts, away from the central lesion

In the corticospinal and spinothalamic tracts the cervical fibres lie medially and the sacral fibres laterally. A central haemorrhage or oedema damages cervical fibres first and spares the peripheral sacral fibres, producing arms-worse-than-legs weakness with sacral sparing.

Option by option

A. The sacral roots leave the cord below the level of the injury
Sacral roots do arise below the injury, but that does not explain preserved tract function.
B. Sacral fibres run in the posterior columns, which a central lesion spares
Sacral spinothalamic and corticospinal fibres are not in the posterior columns.
C. Sacral fibres lie peripherally in the lateral tracts, away from the central lesion (correct)
Correct. Lamination places sacral fibres outermost, so a central lesion spares them.
D. The sacral cord is supplied by the posterior spinal arteries alone
The anterior spinal artery also supplies the central cord, and the sacral cord is not supplied by the posterior arteries alone.

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 Anatomy question

What is the answer to this Anatomy question?

The best answer is C, Sacral fibres lie peripherally in the lateral tracts, away from the central lesion. In the corticospinal and spinothalamic tracts the cervical fibres lie medially and the sacral fibres laterally.

Why is "The sacral roots leave the cord below the level of the injury" not the answer?

Sacral roots do arise below the injury, but that does not explain preserved tract function.

Why is "Sacral fibres run in the posterior columns, which a central lesion sp…" not the answer?

Sacral spinothalamic and corticospinal fibres are not in the posterior columns.

Why is "The sacral cord is supplied by the posterior spinal arteries alone" not the answer?

The anterior spinal artery also supplies the central cord, and the sacral cord is not supplied by the posterior arteries alone.

What concept does this question test?

It tests Neuroanatomy: central cord syndrome in Anatomy. A central haemorrhage or oedema damages cervical fibres first and spares the peripheral sacral fibres, producing arms-worse-than-legs weakness with sacral sparing.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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 Neuroanatomy: central cord syndrome?

Learn every nerve by its route, its muscles and what a lesion looks like at the bedside. That one habit answers a large share of questions. Then use the flashcards and the other Anatomy 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.