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
Earliest site of bone involvement in hematogenous osteomyelitis is - 
Select and explain. 
A. Metaphysis, B. Epiphysis, C. Diaphysis, D. Apophysis
A: Metaphysis
Answer: A: Metaphysis 
Explanation: Ans. is 'a' i.e., Metaphysis Pathophysiology of acute osteomyelitiso Organism reach the bone through blood stream from a septic focus elsewhere in the body, o Metaphysis of long bone is the earliest and most common site involved because : -Metaphysis is highly vascularCommonest site is metaphysis. This is because of the peculiar arrangement of the blood vessels in that area, which leads to relative vascular stasis, favouring bacterial colonization..Metaphysis has relatively few phagocytic cells than physis or diaphysis.Metaphysis has thin cortex.