Embryology: amniotic band 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 · Embryology: amniotic band syndrome

Sample item

A newborn has a constriction ring around one leg with distal oedema, asymmetrical digit amputations and craniofacial clefts that do not follow embryonic fusion lines. What is the likely cause?

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

The answer and the reasoning

B. Entrapment by fibrous bands after early amnion rupture

Early rupture of the amnion releases fibrous bands that entangle parts of the fetus, causing constriction rings, amputations and bizarre clefts. The pattern is asymmetric and does not follow the usual developmental fields.

Option by option

  • A. Maternal thalidomide exposure

    Thalidomide causes symmetrical limb reduction such as phocomelia.

  • B. Entrapment by fibrous bands after early amnion rupture (correct)

    Correct. Fibrous amniotic bands constrict and amputate fetal parts asymmetrically.

  • C. Defective signalling from the zone of polarising activity

    Defective zone of polarising activity signalling alters anteroposterior limb patterning, not constriction rings.

  • D. Failure of the apical ectodermal ridge to induce outgrowth

    Apical ectodermal ridge failure causes transverse limb truncation without constriction rings.

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 B, Entrapment by fibrous bands after early amnion rupture. Early rupture of the amnion releases fibrous bands that entangle parts of the fetus, causing constriction rings, amputations and bizarre clefts.

Why is "Maternal thalidomide exposure" not the answer?

Thalidomide causes symmetrical limb reduction such as phocomelia.

Why is "Defective signalling from the zone of polarising activity" not the answer?

Defective zone of polarising activity signalling alters anteroposterior limb patterning, not constriction rings.

Why is "Failure of the apical ectodermal ridge to induce outgrowth" not the answer?

Apical ectodermal ridge failure causes transverse limb truncation without constriction rings.

What concept does this question test?

It tests Embryology: amniotic band syndrome in Anatomy. The pattern is asymmetric and does not follow the usual developmental fields.

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 Embryology: amniotic band 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.