This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Infection of Bones & Joints, Subject name: Orthopaedics
[{'content': 'Earliest X-Ray finding in Osteomyelitis: \nSelect and explain. \nA. Involucrum, B. Sequestrum, C. Cloacae, D. Periosteal reaction', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. (d) Periosteal reactionRef. Maheshwari 8th ed. /169; Harrison's 18th cd. Ch 126* Earliest X-Ray change: Loss of soft tissue plane which is seen after 24 hours. In case of osteomyelitis X-Ray is normal during first 24 hours.* 2nd X-Ray change seen in periosteal reaction, which is usually seen 7-10 days after infection.* Periosteal reaction can be of 3 types:# No reaction: seen in case of TB# Narrow zone of activity: Benign condition (Ex: in infection like osteomyelitis)# Wide zone of activity: Malignant condition (Ex: Codmans triangle in osteosarcoma)", 'role': 'assistant'}]