Musculoskeletal imaging: cam femoroacetabular impingement: practice question

A Radiology 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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Radiology · Musculoskeletal imaging: cam femoroacetabular impingement

Sample item

A 25-year-old footballer has groin pain on hip flexion and internal rotation. A cross-table lateral radiograph shows a bump at the femoral head-neck junction with an increased alpha angle. Which mechanism is most likely?

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

The answer and the reasoning

A. Cam-type femoroacetabular impingement

An aspherical femoral head or head-neck bump, shown by an increased alpha angle, impinges on the acetabular rim in flexion and rotation and is typical of cam impingement in young active men. Pincer impingement arises from acetabular overcoverage, and the other options have different radiographic features.

Option by option

  • A. Cam-type femoroacetabular impingement (correct)

    Correct. A head-neck bump with a raised alpha angle is cam impingement.

  • B. Legg-Calve-Perthes disease

    Perthes disease affects children with femoral head collapse.

  • C. Pincer-type femoroacetabular impingement

    Pincer impingement is caused by an overcovering acetabulum, not a femoral bump.

  • D. Transient osteoporosis of the hip

    Transient osteoporosis shows osteopenia with marrow oedema, not a bump.

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 Radiology question

What is the answer to this Radiology question?

The best answer is A, Cam-type femoroacetabular impingement. An aspherical femoral head or head-neck bump, shown by an increased alpha angle, impinges on the acetabular rim in flexion and rotation and is typical of cam impingement in young active men.

Why is "Legg-Calve-Perthes disease" not the answer?

Perthes disease affects children with femoral head collapse.

Why is "Pincer-type femoroacetabular impingement" not the answer?

Pincer impingement is caused by an overcovering acetabulum, not a femoral bump.

Why is "Transient osteoporosis of the hip" not the answer?

Transient osteoporosis shows osteopenia with marrow oedema, not a bump.

What concept does this question test?

It tests Musculoskeletal imaging: cam femoroacetabular impingement in Radiology. Pincer impingement arises from acetabular overcoverage, and the other options have different radiographic features.

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 Musculoskeletal imaging: cam femoroacetabular impingement?

Learn signs with the image, and the disease they point to. Then use the flashcards and the other Radiology 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.