Bone and joint infections: Batson plexus in vertebral osteomyelitis: practice question

A Orthopaedics 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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Orthopaedics · Bone and joint infections: Batson plexus in vertebral osteomyelitis

Sample item

A 66-year-old man with a recent urinary tract infection and catheterisation has fever and low back pain. MRI shows destruction of the L3-L4 disc and adjacent endplates. Which anatomical route best explains how a pelvic infection can seed the vertebrae without a systemic arterial source?

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

The answer and the reasoning

D. Retrograde flow in the valveless paravertebral venous plexus

The vertebral venous plexus described by Batson is valveless and communicates with the pelvic veins. Raised intra-abdominal pressure can reverse flow and carry bacteria to the vertebral bodies, which explains vertebral seeding from urinary or pelvic infection. The same route carries pelvic and prostatic cancer to the spine.

Option by option

  • A. Direct extension through the intervertebral foramina

    The foramina transmit nerves and vessels but infection from the urinary tract does not reach the spine by direct extension.

  • B. Lymphatic spread through the thoracic duct

    The thoracic duct drains lymph into the venous system and does not deliver bacteria to vertebral bodies.

  • C. Spread along the psoas sheath to the vertebral bodies

    The psoas sheath is a pathway for an abscess to track downward from the spine, not a route of seeding into it.

  • D. Retrograde flow in the valveless paravertebral venous plexus (correct)

    Correct. Reversed flow in this valveless plexus carries pelvic organisms to the vertebrae.

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.

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Questions about this Orthopaedics question

What is the answer to this Orthopaedics question?

The best answer is D, Retrograde flow in the valveless paravertebral venous plexus. The vertebral venous plexus described by Batson is valveless and communicates with the pelvic veins.

Why is "Direct extension through the intervertebral foramina" not the answer?

The foramina transmit nerves and vessels but infection from the urinary tract does not reach the spine by direct extension.

Why is "Lymphatic spread through the thoracic duct" not the answer?

The thoracic duct drains lymph into the venous system and does not deliver bacteria to vertebral bodies.

Why is "Spread along the psoas sheath to the vertebral bodies" not the answer?

The psoas sheath is a pathway for an abscess to track downward from the spine, not a route of seeding into it.

What concept does this question test?

It tests Bone and joint infections: Batson plexus in vertebral osteomyelitis in Orthopaedics. Raised intra-abdominal pressure can reverse flow and carry bacteria to the vertebral bodies, which explains vertebral seeding from urinary or pelvic infection. The same route carries pelvic and prostatic cancer to the spine.

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 Bone and joint infections: Batson plexus in vertebral osteomyelitis?

Pair each fracture with its classic complication and nerve injured. Then use the flashcards and the other Orthopaedics 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.