Which vertebral region is most commonly affected in Pott disease?

Explanation

## Anatomical Distribution in Pott Disease **Key Point:** The thoracic and lumbar spine are the most frequently involved sites in spinal tuberculosis, accounting for approximately 50% and 35% of cases respectively. ### Frequency by Region | Spinal Region | Frequency | Notes | | --- | --- | --- | | Thoracic | ~50% | Most common; often multiple contiguous vertebrae | | Lumbar | ~35% | Second most common | | Cervical | ~10% | Least common; associated with higher morbidity | | Sacral | <5% | Rare; difficult to diagnose | ### Pathophysiological Basis 1. **Vascular supply predilection** — The vertebral bodies of the thoracic and lumbar regions have rich cancellous bone with slow blood flow, favoring hematogenous seeding of *Mycobacterium tuberculosis*. 2. **Weight-bearing stress** — These regions bear maximum axial load, creating an environment conducive to bacterial proliferation and vertebral body destruction. 3. **Contiguous spread** — Once established, infection spreads to adjacent vertebrae via the anterior longitudinal ligament and intervertebral disc. **High-Yield:** The disease typically begins in the vertebral body (not the posterior elements) and spreads anteriorly, leading to characteristic anterior vertebral body collapse and kyphotic deformity. **Clinical Pearl:** Cervical involvement, though rare, carries a higher risk of neurological complications due to the narrow spinal canal and proximity to vital neurovascular structures.