A Case Study for the Spine Fracture of a Pedestrian Impacted by SUV.

Korean J Leg Med. 2005 Oct;29(2):135-140. Korean.

Traffic Engineering Div., Forensic Science Dept., Forensic Medicine Div., Forensic Medicine Dept., National Institute of Scientific Investigation. sungji@nisi.go.kr

Mechanical Engineering Dept., Korea University.

The civilization has given us a great comfort and convenience but also it has been threatening our life at the same time. Among these causes of death the traffic accident is the most dangerous thing to threat our life in recent years. According to the report of traffic accident in 2003, the pedestrian to car accident is almost 50% of all types of traffic accident and this percentage is very high level compare to other countries. So this is why we have to focus on this field of accident. This case is as follows, when a pedestrian was riding a bicycle and crossing the road, a taxi hit the bicycle with left outside mirror. The impact was not so severe, the pedestrian stood up by himself. Unfortunately he was impacted once again by a SUV which was following behind the taxi. The evidence were the SUV, clothing and victim. A complete autopsy was performed on the victim. The skull was slightly fractured with line shape and showed hypodermal bleeding under the head skin. The thoracic vertebrae of No. 11-12 was fractured. The cause of death was apparently head trauma and fracture of thoracic vertebrae. But we could not explain why the thoracic vertebrae was fractured without damage of internal organs in chest and abdomen. To analyze this case, we used a dynamic analysis program Madymo V6.2 and applied the Hybrid-III human model. Finally we could prove that if the pedestrian stand against the SUV, the bending moment in spine was raised suddenly at the beginning of impact. At this moment the leg was started to be move to the backward of pedestrian but the upper part of body could not move because of inertia. This bending moment make the spine hyper-extension and this level of moment can fracture the spine enough in low speed of SUV. In this study we analysis the car to pedestrian accident with engineering view and introduce the detail analysis method to reconstruct the accident involving the human trauma.

Key Words : pedestrian, fracture, thoracic vertebrae, madymo, human model