Finite element analysis dynamic simulation of projectile impact caliber .40 S&W in temporal bone with neural tissue

Aim: Temporal bone is often hit by projectiles. Temporal gunshot wounds must be deeply evaluated in order to establish wound morphology and stress distribution. Finite element analysis is a promising tool that can support forensic aspects. Ballistic studies have already been performed by finite element analysis. However, all involved only the simulation of bone tissues. Until the present study, it remained unknown whether the presence of soft neural tissues would alter the outcome of the analysis. Material and Methods: Segmentation of bone anatomical structures was performed in Materialize MIMICS Research v. 18 (Materialize Belgium) from cone beam tomography data of a dry skull. Three-dimensional finite element model of the dry skull fulfilled with neural soft tissue and projectile .40 S&W -caliber flat point were obtained in Ansys v17.2 and Rhinoceros. Two situations were simulated in Ansys v17.2. Leaning shots fired at 90° with and without neural soft tissue. Results: Results exhibit different morphologies in entrance bony wounds as well as a strong influence of soft tissue. Von mises stress distribution and energy loss showed higher values at the presence of neural tissue. There was projectile deviation downwards with neural tissues. There was a good reproducibility between bone and neural tissue real behavior and the finite element model built. Conclusion: The presence of neural soft tissue cannot be neglected, since it does alter results.