Thorax: first rib relations: 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 · Thorax: first rib relations

Sample item

On the superior surface of the first rib, the scalene tubercle gives attachment to scalenus anterior. Which structure lies in the groove immediately behind the tubercle?

AInternal thoracic arteryBSubclavian veinCSubclavian artery and lower trunkDPhrenic nerve

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

The answer and the reasoning

C. Subclavian artery and lower trunk

The subclavian vein runs in the groove in front of the scalene tubercle, while the subclavian artery and the lower trunk of the brachial plexus run in the groove behind it. Both pass over the first rib on their way to the axilla. A cervical rib can compress the artery and the lower trunk.

Option by option

A. Internal thoracic artery
The internal thoracic artery arises from the first part of the subclavian and descends behind the costal cartilages.
B. Subclavian vein
The subclavian vein lies in front of the tubercle, separated from the artery by scalenus anterior.
C. Subclavian artery and lower trunk (correct)
Correct. The artery and lowest trunk of the plexus pass behind the tubercle.
D. Phrenic nerve
The phrenic nerve crosses the front of scalenus anterior and not the rib groove.

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, Subclavian artery and lower trunk. The subclavian vein runs in the groove in front of the scalene tubercle, while the subclavian artery and the lower trunk of the brachial plexus run in the groove behind it.

Why is "Internal thoracic artery" not the answer?

The internal thoracic artery arises from the first part of the subclavian and descends behind the costal cartilages.

Why is "Subclavian vein" not the answer?

The subclavian vein lies in front of the tubercle, separated from the artery by scalenus anterior.

Why is "Phrenic nerve" not the answer?

The phrenic nerve crosses the front of scalenus anterior and not the rib groove.

What concept does this question test?

It tests Thorax: first rib relations in Anatomy. Both pass over the first rib on their way to the axilla. A cervical rib can compress the artery and the lower trunk.

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 Thorax: first rib relations?

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.