Spine: Denis three-column concept: practice question

A Orthopaedics 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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Orthopaedics · Spine: Denis three-column concept

Sample item

According to Denis, which feature makes a thoracolumbar injury mechanically unstable?

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

The answer and the reasoning

D. Disruption of at least two of the three columns

Denis described anterior (anterior longitudinal ligament and anterior two-thirds of the body), middle (posterior third of the body and posterior longitudinal ligament) and posterior (neural arch and ligaments) columns. Failure of the middle column together with another is considered unstable.

Option by option

  • A. A single transverse process fracture

    Transverse process fractures are stable.

  • B. Fracture of a spinous process only

    Spinous process fractures are minor stable injuries.

  • C. Disruption of the anterior column only

    Isolated anterior column injury such as a wedge fracture is usually stable.

  • D. Disruption of at least two of the three columns (correct)

    Correct. Two-column failure, especially including the middle column, is unstable.

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.

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Questions about this Orthopaedics question

What is the answer to this Orthopaedics question?

The best answer is D, Disruption of at least two of the three columns. Denis described anterior (anterior longitudinal ligament and anterior two-thirds of the body), middle (posterior third of the body and posterior longitudinal ligament) and posterior (neural arch and ligaments) columns.

Why is "A single transverse process fracture" not the answer?

Transverse process fractures are stable.

Why is "Fracture of a spinous process only" not the answer?

Spinous process fractures are minor stable injuries.

Why is "Disruption of the anterior column only" not the answer?

Isolated anterior column injury such as a wedge fracture is usually stable.

What concept does this question test?

It tests Spine: Denis three-column concept in Orthopaedics. Failure of the middle column together with another is considered unstable.

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 Spine: Denis three-column concept?

Pair each fracture with its classic complication and nerve injured. Then use the flashcards and the other Orthopaedics 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.