<prompt> Which of the following is not TRUE about osteomyelitis?Epiphysis most commonly involved regionIn sickle cell anemia salmonella is causative organismSequestrum is a piece of dead boneInvolvement is dense sclerotic bone overlying a sequestrum  <response>: Acute osteomyelitis is almost invariably a disease of children. The causative organism is usually staphylococcus aureus 60-80 of cases, less often streptococcus pyogenes and streptococcus pneumoniae. In children Patients with sickle cell disease are prone to infection by salmonella. Metaphysis is common site of osteomyelitis because of hairpin arrangements of blood vessels, Rapid growth in the region, Defective phagocytosis in the region and metaphyseal hemorrhage due to trauma in the region. The lower femoral metaphysis is commonest site for osteomyelitis. Sequestrum is a piece of dead bone, surrounded by a infected granulation tissue. Involucrum is a dense sclerotic bone overlying sequestrum. Ref: Apleys 8e, Page 28,32; Ebnezar Textbook of Ohopedics By John Ebnezar 4e, Page 541-42; Maheswari 3e, Page 157-162. 