## 4 Discussion  
A previous study reported that when falling, the body position at the time of impact was a significant factor that affected injury severity and an impact to the lateral region was a significant factor that influenced the injury severity score [20]. Therefore, the mechanism \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Factor** & **Degree of Freedom** & **F Value** & \(p\) **Value** & **Contribution Rate** \\ \hline Pitch angle & 1 & 33.56 & 0.00001 & 10.10\% \\ Roll angle & 2 & 8.37 & 0.00186 & 4.57\% \\ Lateral bending of the face & 1 & 74.12 & 0.00001 & 22.70\% \\ Impact object & 3 & 26.13 & 0.00001 & 23.40\% \\ Pitch angle and roll angle & 2 & 7.03 & 0.00413 & 3.74\% \\ Pitch angle and lateral bending of the face & 1 & 16.79 & 0.00044 & 4.90\% \\ Pitch angle and falling surface & 3 & 7.70 & 0.00097 & 6.24\% \\ Roll angle and lateral bending of the face & 2 & 7.38 & 0.00334 & 3.96\% \\ Roll angle and falling surface & 6 & 4.27 & 0.00494 & 6.09\% \\ Impact object and lateral bending of the face & 3 & 0.68 & 0.57087 & 0\% \\ Error & & & & 14.28\% \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Results of the analysis of variance and contribution rates. Figure 7: Estimation of the factor effect. of injury related to a lateral impact when falling should be analyzed to reduce the severity of injuries related to falling. Reconstruction technology using computer simulations has been widely used to analyze injuries. Specifically, reconstructions of falls by means of computer simulation models have been performed. FE models can be used to simulate deformation modes and force responses accurately. In addition, it is possible to predict whether bones would fracture under given impact conditions by assuming their stress-strain properties around the fracture sites. Research using a human FE model is an advanced method of predicting impact behavior and mechanical responses. The mechanisms involved in mandibular injuries have been evaluated using FE models of the mandible [11; 12; 13; 21]. [PERSON] et al. simulated the conditions of a lateral fall using an FE model of the mandible, but in the present study, we reconstructed a lateral fall using a more sophisticated whole-body FE model [13]. [PERSON] et al. characterized the mechanisms of mandibular fractures in cyclists using the same FE model as in the present study [21]. They reconstructed cyclist injury scenarios, namely an individual falls from a bicyclist in a forward direction and their face makes contact with the road surface, using a similar simulation model to our analysis. Since the mandible was the most common fractured site, they reconstructed injuries to the frontal region of the mandible. In these simulations, higher von Mises stresses were noted in the mandible when the center of the mandibular body struck the road surface. The conditions leading to and frequent sites of mandibular fracture due to a lateral impact as well as the main contributing factors, were examined using FE model analyses in the present study. The impact object and angle of lateral bending of the face strongly influenced the occurrence of mandibular fractures. Contact of the center of the head with the concrete block was the most probable cause of mandibular fractures. When a victim falls laterally, the shoulder or upper arm contacts the road surface before the head, and the speed of the fall of the whole body is reduced, leading to a decreased impact force on the face. However, if the protruding object contacts the center of the head, a higher stress might be produced at the face. Regarding the lateral bending of the face, bending to the opposite side of the falling direction by \(20^{\circ}\) was the most probable condition, resulting in higher stress to the mandible. If there is no bending, the lateral head will have the dominant contact with the block, and less force will be applied to the mandible. In addition, the pitch angle also influenced the occurrence of mandible fractures.