Neuroanatomy: optic radiation: 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 · Neuroanatomy: optic radiation

Sample item

A 50-year-old woman with a right parietal lobe tumour notices that she misses objects on the floor to her left, with a field defect below the horizontal meridian in both eyes. Which fibres are interrupted?

ARight superior optic radiation in the parietal lobeBLeft optic nerve at the orbital apexCRight optic tract before the geniculate bodyDRight inferior optic radiation in the temporal lobe

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

The answer and the reasoning

A. Right superior optic radiation in the parietal lobe

The superior fibres of the optic radiation pass through the parietal lobe and carry the lower visual field to the upper bank of the calcarine sulcus. Their interruption causes a contralateral inferior quadrantanopia, whereas fibres looping through the temporal lobe carry the upper field.

Option by option

A. Right superior optic radiation in the parietal lobe (correct)
Correct. Parietal fibres carry the opposite lower quadrant, matching the field loss.
B. Left optic nerve at the orbital apex
A left optic nerve lesion would cause monocular visual loss in the left eye alone.
C. Right optic tract before the geniculate body
An optic tract lesion causes a full homonymous hemianopia rather than a single quadrant.
D. Right inferior optic radiation in the temporal lobe
The temporal loop carries the upper visual field, so its interruption would cause a superior quadrantanopia.

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 A, Right superior optic radiation in the parietal lobe. The superior fibres of the optic radiation pass through the parietal lobe and carry the lower visual field to the upper bank of the calcarine sulcus.

Why is "Left optic nerve at the orbital apex" not the answer?

A left optic nerve lesion would cause monocular visual loss in the left eye alone.

Why is "Right optic tract before the geniculate body" not the answer?

An optic tract lesion causes a full homonymous hemianopia rather than a single quadrant.

Why is "Right inferior optic radiation in the temporal lobe" not the answer?

The temporal loop carries the upper visual field, so its interruption would cause a superior quadrantanopia.

What concept does this question test?

It tests Neuroanatomy: optic radiation in Anatomy. Their interruption causes a contralateral inferior quadrantanopia, whereas fibres looping through the temporal lobe carry the upper field.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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 Neuroanatomy: optic radiation?

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.