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': 'Earliest site of bone involvement in hematogenous osteomyelitis is ? \nSelect and explain. \nA. Metaphysis, B. Epiphysis, C. Diaphysis, D. Apophysis', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Metaphysis Pathophysiology of acute osteomyelitis Organism reach the bone through blood stream from a septic focus elsewhere in the body. Metaphysis of long bone is the earliest and most common site involved because : - i) Metaphysis is highly vascular ii) Commonest site is metaphysis. This is because of the peculiar arrangement of the blood vessels in that area, which leads to relative vascular stasis, ouring bacterial colonization. . iii) Metaphysis has relatively few phagocytic cells than physis or diaphysis. iv) Metaphysis has thin coex.", 'role': 'assistant'}]