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
How many Champy's osteosynthesis lines exist behind and in front of mental foramen? 
Select and explain. 
A. 2 ahead of and 2 behind the mental foramen, B. 1 ahead of and 2 behind the mental foramen, C. 2 ahead of and 1 behind the mental foramen, D. 1 ahead of and 1 behind the mental foramen
C: 2 ahead of and 1 behind the mental foramen
Answer: C: 2 ahead of and 1 behind the mental foramen 
Explanation: Champy described the ideal osteosynthesis lines, which were the areas in mandible which if plated correctly with mini plates and screws, could give adequate functionalstability to the mandible. These were 2 lines in the symphysis and para-symphysis region (anterior to the mental foramen) and 1 line in the body region that curved upward along the external oblique ridge to the anterior border of ramus in the angle region (behind mental foramen). If mini-plates with at least 2 mono-cortical screws of adequate thickness on each side of racture line were applied in these areas, it could give a semi rigid or a functionally stable fixation to the patient without the need of IMF.