Anatomy: structures through the annulus of Zinn: practice question

A Ophthalmology 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.

Try it

Ophthalmology · Anatomy: structures through the annulus of Zinn

Sample item

Which of the following structures passes through the common tendinous ring (annulus of Zinn) and not outside it in the superior orbital fissure?

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

The answer and the reasoning

D. Nasociliary nerve

The annulus of Zinn transmits the optic nerve, both divisions of the oculomotor nerve, the nasociliary nerve and the abducens nerve. The trochlear, frontal and lacrimal nerves and the superior ophthalmic vein lie outside the ring. This explains why only some structures are affected in different orbital apex lesions.

Option by option

  • A. Lacrimal nerve

    The lacrimal nerve passes outside the annulus on the lateral side.

  • B. Frontal nerve

    The frontal nerve runs outside the annulus, above the levator.

  • C. Trochlear nerve

    The trochlear nerve passes above the ring, outside the annulus of Zinn.

  • D. Nasociliary nerve (correct)

    Correct. The nasociliary branch of V1 passes inside the annulus between the oculomotor divisions.

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 Ophthalmology questions

Questions about this Ophthalmology question

What is the answer to this Ophthalmology question?

The best answer is D, Nasociliary nerve. The annulus of Zinn transmits the optic nerve, both divisions of the oculomotor nerve, the nasociliary nerve and the abducens nerve.

Why is "Lacrimal nerve" not the answer?

The lacrimal nerve passes outside the annulus on the lateral side.

Why is "Frontal nerve" not the answer?

The frontal nerve runs outside the annulus, above the levator.

Why is "Trochlear nerve" not the answer?

The trochlear nerve passes above the ring, outside the annulus of Zinn.

What concept does this question test?

It tests Anatomy: structures through the annulus of Zinn in Ophthalmology. The trochlear, frontal and lacrimal nerves and the superior ophthalmic vein lie outside the ring. This explains why only some structures are affected in different orbital apex lesions.

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 Anatomy: structures through the annulus of Zinn?

Group the red eye by what to examine and what the pupil does. Then use the flashcards and the other Ophthalmology 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.