How does Pott disease cause collapse of the vertebrae and a hunchback deformity?

Pott disease, also known as tuberculous spondylitis, occurs when the tuberculosis bacillus (Mycobacterium tuberculosis) infects the vertebral column.12

The infection typically begins in the body of a vertebra, which is the most common site for bone tuberculosis. As the infection progresses, it causes the bone to soften and eventually collapse. Because the vertebral bodies are weakened and destroyed, they can no longer support the weight of the upper body effectively. This structural failure leads to the characteristic hunchback deformity, medically referred to as kyphosis, which is an increased outward curvature of the thoracic spine.134

As the disease spreads to contiguous structures, it may lead to the formation of abscesses that drain into adjacent soft tissues. While modern chemotherapy and orthopedic care have made the condition rare in developed nations, it remains a serious health concern in many parts of the world, particularly among children.1