This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': 'Which of the following is not TRUE about osteomyelitis? \nSelect and explain. \nA. Epiphysis most commonly involved region, B. In sickle cell anemia salmonella is causative organism, C. Sequestrum is a piece of dead bone, D. Involvement is dense sclerotic bone overlying a sequestrum', 'role': 'user'}, {'content': "Answer: A \nExplanation: 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: Apley's 8/e, Page 28,32; Ebnezar Textbook of Ohopedics By John Ebnezar 4/e, Page 541-42; Maheswari 3/e, Page 157-162.", 'role': 'assistant'}]