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
Commonest cause of hematogenous osteomyelitis: March 2011 
Select and explain. 
A. Streptococcus, B. Staph. aureus, C. Salmonella, D. H. influenza
B: Staph. aureus
Answer: B: Staph. aureus 
Explanation: Ans. B: Staph. aureus Staphylococcus aureus is the commonest causative organism causing acute osteomyelitis Osteomyelitis: Earliest site of involvement in bone: Metaphysis Brodie's abscess: A static cavity remains in bone, without fuher enlargement. Blood culture are positive in 65% of cases Periosteal reaction may be the radiological sign visible (after 10 days) MC cause of acute osteomyelitis: Staph. Aureus