sequestrum

thumb|right|X-ray of a child's femur, showing a bony sequestrum indicated by the blue arrow. A sequestrum (plural: sequestra) is a piece of dead bone that has become separated during necrosis from normal or sound bone. It is a complication (sequela) of osteomyelitis.

The pathological process is as follows: infection in the bone leads to an increase in intramedullary pressure due to inflammatory exudates the periosteum becomes stripped from the ostium, leading to vascular thrombosis lack of blood supply causes bone necrosis sequestra are formed