Embryology: digit separation: 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: digit separation

Sample item

A newborn has fusion of the skin and soft tissue between the third and fourth fingers. Failure of which process during the seventh and eighth weeks is responsible?

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

The answer and the reasoning

B. Programmed cell death of interdigital tissue

The fingers separate when the tissue between the digital rays is removed by apoptosis during the seventh and eighth weeks. If this programmed cell death fails, syndactyly results.

Option by option

  • A. Outgrowth of the apical ectodermal ridge

    Apical ectodermal ridge outgrowth lengthens the limb, and its loss would truncate the limb.

  • B. Programmed cell death of interdigital tissue (correct)

    Correct. Interdigital apoptosis separates the digits, and its failure causes syndactyly.

  • C. Chondrification of the phalanges

    Chondrification forms the skeletal template and is unrelated to webbing.

  • D. Proliferation of digital ray mesenchyme

    Proliferation of ray mesenchyme builds the digits and does not remove tissue between them.

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, Programmed cell death of interdigital tissue. The fingers separate when the tissue between the digital rays is removed by apoptosis during the seventh and eighth weeks.

Why is "Outgrowth of the apical ectodermal ridge" not the answer?

Apical ectodermal ridge outgrowth lengthens the limb, and its loss would truncate the limb.

Why is "Chondrification of the phalanges" not the answer?

Chondrification forms the skeletal template and is unrelated to webbing.

Why is "Proliferation of digital ray mesenchyme" not the answer?

Proliferation of ray mesenchyme builds the digits and does not remove tissue between them.

What concept does this question test?

It tests Embryology: digit separation in Anatomy. If this programmed cell death fails, syndactyly results.

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: digit separation?

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.