In Pott disease, which of the following describes the characteristic pattern of vertebral body involvement?

Explanation

## Pattern of Vertebral Involvement in Pott Disease **Key Point:** Pott disease characteristically begins in the anterior vertebral body, typically at the junction of the vertebral body and epiphysis, with relative sparing of posterior elements in the early stages. ### Pathological Progression ### Stage 1: Initial Involvement (Anterior Vertebral Body) 1. Infection begins in the metaphyseal region of the vertebral body 2. Granulation tissue and caseous necrosis develop 3. Posterior elements remain uninvolved initially 4. Disc space may be secondarily involved ### Stage 2: Progressive Destruction 1. Anterior vertebral body collapse occurs 2. Kyphotic deformity develops 3. Posterior ligaments stretch but remain intact 4. Spinal cord compression develops gradually ### Stage 3: Late Complications 1. Posterior element involvement (late) 2. Abscess formation (cold abscess) 3. Severe kyphosis and neurological deficit **High-Yield:** The **anterior vertebral body involvement with posterior element sparing** is the hallmark distinguishing feature of Pott disease from other spinal infections (e.g., pyogenic spondylitis, which may involve multiple sites). ### Why Anterior Vertebral Body? **Clinical Pearl:** The metaphyseal region of the vertebral body has the richest blood supply from nutrient arteries, making it the primary site of hematogenous seeding in tuberculosis. ### Mnemonic **POTT = Posterior sparing, Organism (TB), Thoracolumbar, Trabecular involvement** [cite:Robbins 10e Ch 8; Campbell's Operative Orthopaedics 13e Ch 42]