Abdomen and pelvis: obstetric conjugate: 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.

Try it

Anatomy · Abdomen and pelvis: obstetric conjugate

Sample item

Which anteroposterior diameter of the pelvic inlet is the shortest, being the most useful obstetrically, and cannot be measured directly in a living woman?

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

The answer and the reasoning

C. Obstetric conjugate

The obstetric conjugate runs from the sacral promontory to the nearest point on the back of the symphysis pubis, and it is the narrowest anteroposterior inlet diameter through which the fetal head must pass. It is estimated by subtracting a small allowance from the diagonal conjugate.

Option by option

  • A. Anatomical conjugate

    This runs to the upper border of the symphysis and is longer than the obstetric conjugate.

  • B. Diagonal conjugate

    This diameter is longer and can be reached by vaginal examination to the promontory.

  • C. Obstetric conjugate (correct)

    Correct. It is the shortest anteroposterior diameter of the inlet and is estimated, not measured.

  • D. Interspinous diameter

    This is a transverse midpelvic measurement between the ischial spines, not an anteroposterior inlet diameter.

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 C, Obstetric conjugate. The obstetric conjugate runs from the sacral promontory to the nearest point on the back of the symphysis pubis, and it is the narrowest anteroposterior inlet diameter through which the fetal head must pass.

Why is "Anatomical conjugate" not the answer?

This runs to the upper border of the symphysis and is longer than the obstetric conjugate.

Why is "Diagonal conjugate" not the answer?

This diameter is longer and can be reached by vaginal examination to the promontory.

Why is "Interspinous diameter" not the answer?

This is a transverse midpelvic measurement between the ischial spines, not an anteroposterior inlet diameter.

What concept does this question test?

It tests Abdomen and pelvis: obstetric conjugate in Anatomy. It is estimated by subtracting a small allowance from the diagonal conjugate.

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 Abdomen and pelvis: obstetric conjugate?

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.