In spinal tuberculosis (Pott's disease), the anterior column is predominantly affected because:

• A The posterior column has a richer blood supply that clears mycobacteria more effectively
• B Mycobacterium tuberculosis reaches the vertebral bodies via the paravertebral venous plexus, and the subchondral bone with its end-arterial circulation is most susceptible to haematogenous seeding ✓
• C The disc space acts as a barrier to posterior spread, confining infection to the posterior elements
• D The anterior longitudinal ligament promotes abscess tracking, spreading infection anteriorly

Explanation

Spinal TB begins in the vertebral body (anterior column), typically in the anteroinferior or anterosuperior region near the end plate, because haematogenous spread via the nutrient arteries seeds the subchondral region, which has end-arterial circulation and relative tissue hypoxia. The infection then erodes into the avascular disc, which has no immune cells or blood supply to contain the mycobacteria. Contrary to option C, the disc is primarily a victim, not a barrier. The posterior elements are relatively spared unless there is paradiscal involvement.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.