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
Injury to popliteal aery in fracture lower end of femur can be caused by ? 
Select and explain. 
A. Proximal fragment, B. Muscle haematoma, C. Distal fragment, D. Tissue swelling
C: Distal fragment
Answer: C: Distal fragment 
Explanation: Ans. is 'c' i.e., Distal fragment In distal third shaft fracture or supracondylar femur fracture, the distal fragment is tilted backward due to strong gastrocnemius pull. This posteriorly tilted distal fragment can cause popliteal aery injury.