All are true about chronic osteomyelitis except ?

Ans. is 'c' i.e., Involucrum is dead bone Pathology in chronic osteomyelitis Chronic osteomyelitis occurs most commonly in long bones. Bone is destroyed or devitalized in the affected pa. Cavities containing pus and pieces of dead bone (sequestra) are surrounded by vascular tissue, and beyond that by areas of sclerosis due to reaction new bone formation, which may take the form of a distinct bony sheath (involucrum) Often sinus track leads to the skin surface; the sinus tends to heal and present down recurrently, but if a sequestrum is present it never heals permanently. This is because sequestra act as substrate for bacterial adhesion in much the same way as foreign implants, ensuring the persistence of infection until they are removed or discharged through perforations in the involucrum and sinuses that drain to the skin. Sequestrum Sequestrum is apiece of dead bone, surrounded by infected granulation tissue trying to eat the sequestrum away. The sequestrum is hard, rough, porus, light in weight and lighter in colour than normal. Normal pattern of bone is lost.(Note : Sequestrum in syphilis and TB is heavier than normal bone because sclerosis usually precedes the death of the bone). On x-ray, sequestra show up as unnatural dense fragments, in contrast to the surrounding osteopenic bone. Involucrum Involucrum is reactive new bone overlying a sequestrum. There may be some holes in the involucrum for pus to drain out. These holes are called cloaca.