Paediatric orthopaedics: amniotic band syndrome: 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 · Paediatric orthopaedics: amniotic band syndrome

Sample item

A newborn has circumferential constriction rings around the forearm with distal lymphoedema, and fusion of the fingertips with proximal clefts. The rest of the skeleton is normal. What is the likely cause?

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

The answer and the reasoning

A. Entanglement of the fetal limb by fibrous amniotic bands

Amniotic band sequence arises when the amnion ruptures and fibrous strands entangle fetal parts, causing constriction rings, distal oedema, acrosyndactyly and sometimes intrauterine amputation. It is sporadic and not inherited. Release of tight rings is done by Z-plasty, and urgent release is needed when the circulation is compromised.

Option by option

  • A. Entanglement of the fetal limb by fibrous amniotic bands (correct)

    Correct. Fibrous bands that encircle the limb in utero give constriction rings and acrosyndactyly.

  • B. Autosomal dominant mutation in the HOX gene family

    HOX mutations cause inherited patterns of synpolydactyly, not sporadic constriction rings.

  • C. Failure of the radial ray to form

    Radial ray failure produces a radial club hand with absent thumb, not circumferential rings.

  • D. Maternal thalidomide exposure

    Thalidomide causes phocomelia and radial ray deficiencies, not ring constrictions.

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 A, Entanglement of the fetal limb by fibrous amniotic bands. Amniotic band sequence arises when the amnion ruptures and fibrous strands entangle fetal parts, causing constriction rings, distal oedema, acrosyndactyly and sometimes intrauterine amputation.

Why is "Autosomal dominant mutation in the HOX gene family" not the answer?

HOX mutations cause inherited patterns of synpolydactyly, not sporadic constriction rings.

Why is "Failure of the radial ray to form" not the answer?

Radial ray failure produces a radial club hand with absent thumb, not circumferential rings.

Why is "Maternal thalidomide exposure" not the answer?

Thalidomide causes phocomelia and radial ray deficiencies, not ring constrictions.

What concept does this question test?

It tests Paediatric orthopaedics: amniotic band syndrome in Orthopaedics. It is sporadic and not inherited. Release of tight rings is done by Z-plasty, and urgent release is needed when the circulation is compromised.

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 Paediatric orthopaedics: amniotic band syndrome?

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.