Local and regional anaesthesia: thoracic kyphosis and spinal spread: practice question

A Anaesthesia 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

Anaesthesia · Local and regional anaesthesia: thoracic kyphosis and spinal spread

Sample item

Hyperbaric bupivacaine is injected at L3-4 in a supine patient and spreads to the mid-thoracic region, then stops rising. Which anatomical feature mainly limits further cephalad spread?

AThe lowest point of the thoracic kyphosisBThe narrowing of the sacral canalCThe cervical lordosisDThe apex of the lumbar lordosis

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

The answer and the reasoning

A. The lowest point of the thoracic kyphosis

A hyperbaric solution settles under gravity toward the lowest part of the spine. In the supine position, this lowest point is in the mid-thoracic region where the thoracic kyphosis lies, so the drug pools there. The apex of the lumbar lordosis is near L3 and is the highest point, so the drug flows away from it.

Option by option

A. The lowest point of the thoracic kyphosis (correct)
Correct. The drug is heavier than CSF and pools at the lowest point of the thoracic curve.
B. The narrowing of the sacral canal
Sacral canal narrowing affects caudal spread, not cephalad spread.
C. The cervical lordosis
The cervical lordosis is higher and the drug rarely reaches it unless the head is lowered.
D. The apex of the lumbar lordosis
The lumbar lordosis apex is a high point in supine patients, so the solution flows away from it.

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 Anaesthesia question

What is the answer to this Anaesthesia question?

The best answer is A, The lowest point of the thoracic kyphosis. A hyperbaric solution settles under gravity toward the lowest part of the spine.

Why is "The narrowing of the sacral canal" not the answer?

Sacral canal narrowing affects caudal spread, not cephalad spread.

Why is "The cervical lordosis" not the answer?

The cervical lordosis is higher and the drug rarely reaches it unless the head is lowered.

Why is "The apex of the lumbar lordosis" not the answer?

The lumbar lordosis apex is a high point in supine patients, so the solution flows away from it.

What concept does this question test?

It tests Local and regional anaesthesia: thoracic kyphosis and spinal spread in Anaesthesia. In the supine position, this lowest point is in the mid-thoracic region where the thoracic kyphosis lies, so the drug pools there. The apex of the lumbar lordosis is near L3 and is the highest point, so the drug flows away from it.

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 Local and regional anaesthesia: thoracic kyphosis and spinal spread?

Make a table of each agent, its key advantage and its main side effect. Then use the flashcards and the other Anaesthesia 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.