Embryology: anorectal malformation: 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: anorectal malformation

Sample item

A newborn boy has no anal opening and passes meconium in the urine. Which embryological error is responsible?

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

The answer and the reasoning

B. Defective urorectal septum partitioning the cloaca

The urorectal septum divides the cloaca into the urogenital sinus anteriorly and the anorectal canal posteriorly. Incomplete division leaves a rectourethral fistula, so meconium passes in the urine.

Option by option

  • A. Non-fusion of the urethral folds

    Non-fusion of the urethral folds causes hypospadias.

  • B. Defective urorectal septum partitioning the cloaca (correct)

    Correct. Incomplete septation of the cloaca leaves a fistula between the rectum and the urinary tract.

  • C. Failed neural crest migration to the rectum

    Failed neural crest migration produces Hirschsprung disease, and the anus is present.

  • D. Persistent vitelline duct to the ileum

    A persistent vitelline duct connects the ileum to the umbilicus and does not involve the anus.

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, Defective urorectal septum partitioning the cloaca. The urorectal septum divides the cloaca into the urogenital sinus anteriorly and the anorectal canal posteriorly.

Why is "Non-fusion of the urethral folds" not the answer?

Non-fusion of the urethral folds causes hypospadias.

Why is "Failed neural crest migration to the rectum" not the answer?

Failed neural crest migration produces Hirschsprung disease, and the anus is present.

Why is "Persistent vitelline duct to the ileum" not the answer?

A persistent vitelline duct connects the ileum to the umbilicus and does not involve the anus.

What concept does this question test?

It tests Embryology: anorectal malformation in Anatomy. Incomplete division leaves a rectourethral fistula, so meconium passes in the urine.

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: anorectal malformation?

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.