Histology: growth plate: 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 · Histology: growth plate

Sample item

An obese 12-year-old boy has hip pain and a limp, and a radiograph shows the femoral epiphysis displaced posteriorly and inferiorly on the neck (slipped capital femoral epiphysis). Through which zone of the growth plate does the slip typically occur?

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

The answer and the reasoning

C. Zone of hypertrophic cartilage

The hypertrophic zone has swollen chondrocytes and little matrix, so it is the mechanically weakest layer of the physis and the site of slippage. Shear forces from obesity and a growth spurt exceed its strength. The slip is then treated by in-situ pinning.

Option by option

  • A. Proliferative (columnar) zone

    The proliferative zone is where chondrocytes divide into columns, and impaired proliferation here underlies achondroplasia.

  • B. Zone of primary spongiosa

    The primary spongiosa is metaphyseal bone laid on calcified cartilage and is a typical site for haematogenous osteomyelitis.

  • C. Zone of hypertrophic cartilage (correct)

    Correct. The hypertrophic zone is the weak layer where shear causes the epiphysis to slip.

  • D. Reserve (resting) zone

    The resting zone anchors the epiphysis and supplies progenitor cells but is not the plane of failure.

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.

More Anatomy questions

Questions about this Anatomy question

What is the answer to this Anatomy question?

The best answer is C, Zone of hypertrophic cartilage. The hypertrophic zone has swollen chondrocytes and little matrix, so it is the mechanically weakest layer of the physis and the site of slippage.

Why is "Proliferative (columnar) zone" not the answer?

The proliferative zone is where chondrocytes divide into columns, and impaired proliferation here underlies achondroplasia.

Why is "Zone of primary spongiosa" not the answer?

The primary spongiosa is metaphyseal bone laid on calcified cartilage and is a typical site for haematogenous osteomyelitis.

Why is "Reserve (resting) zone" not the answer?

The resting zone anchors the epiphysis and supplies progenitor cells but is not the plane of failure.

What concept does this question test?

It tests Histology: growth plate in Anatomy. Shear forces from obesity and a growth spurt exceed its strength. The slip is then treated by in-situ pinning.

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 Histology: growth plate?

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.