Embryology: spina bifida occulta: 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: spina bifida occulta

Sample item

An asymptomatic child has a tuft of hair over the lumbosacral region, and X-ray shows a gap in the L5 vertebral arch. Which description fits the defect?

AExposed open neural plate without skin coverBHerniation of meninges alone through the arch defectCIncomplete fusion of the vertebral arch with intact meninges and cordDProtrusion of meninges and spinal cord through the defect

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

The answer and the reasoning

C. Incomplete fusion of the vertebral arch with intact meninges and cord

Spina bifida occulta is a failure of fusion of the vertebral arches in which the neural tube and meninges are normal and covered by skin. A tuft of hair or a dimple may mark the site, and it is usually asymptomatic.

Option by option

A. Exposed open neural plate without skin cover
An exposed open neural plate describes myeloschisis.
B. Herniation of meninges alone through the arch defect
Meningeal herniation without cord tissue is a meningocele.
C. Incomplete fusion of the vertebral arch with intact meninges and cord (correct)
Correct. Only the bony arch is deficient and the neural tissue is normal.
D. Protrusion of meninges and spinal cord through the defect
Protrusion of cord and meninges is a meningomyelocele.

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.

Questions about this Anatomy question

What is the answer to this Anatomy question?

The best answer is C, Incomplete fusion of the vertebral arch with intact meninges and cord. Spina bifida occulta is a failure of fusion of the vertebral arches in which the neural tube and meninges are normal and covered by skin.

Why is "Exposed open neural plate without skin cover" not the answer?

An exposed open neural plate describes myeloschisis.

Why is "Herniation of meninges alone through the arch defect" not the answer?

Meningeal herniation without cord tissue is a meningocele.

Why is "Protrusion of meninges and spinal cord through the defect" not the answer?

Protrusion of cord and meninges is a meningomyelocele.

What concept does this question test?

It tests Embryology: spina bifida occulta in Anatomy. A tuft of hair or a dimple may mark the site, and it is usually asymptomatic.

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: spina bifida occulta?

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.