Improvement of forensic medical diagnosis of projectile type injuries from automatic firearm chambered in 5.45 mm caliber through spatial 3D modeling

Abstract

Spatial 3D modeling has become one of the modern and most accurate evidential methods of research, carving out its niche in various fields of medical science and practice. Therefore, our focus has been on laying the groundwork for its implementation in the process of conducting forensic medical examinations of gunshot injuries, which have garnered significant attention from all forensic physicians, particularly after unprovoked aggression from Russia and the onset of active hostilities in our country. The aim of the study was to improve the forensic medical diagnosis of projectile type in injuries from automatic firearm AKS-74U chambered in 5.45x39 mm caliber by utilizing spatial 3D modeling of specific elements within the wound channel. The entire series of experimental shots was conducted using an AKS-74U firearm, with a bullet caliber of 5.45x39 mm. As the research material, Roma Plastilina Number 1 ballistic clay, manufactured in the USA, was used for conducting standardized ballistic tests according to NIJ (National Institute of Justice) and HOSDB (Home Office Scientific Development Branch) standards. The series of experiments consisted of 15 gunshots; then the physical characteristics of the bullet, main morphological elements of the wound of skin and different portions of wound channel were investigated (195 measurements in general). The morphological features of individual elements within the wound channel were measured using conventional measurement tools, and also after their 3D modeling using graphic editors such as "Agisoft Photoscan" and "3ds max." Direct and strong correlations (ranging from 0.60 to 0.72) have been established between the initial velocity, kinetic energy, specific energy of bullet, and the diameter of the entry wound in 3D modeling, as well as the diameters of the wound channel in its central portion, measured both by conventional measuring tools and based on the results of their 3D modeling (р=0,02). Furthermore, inverse correlation relationships of moderate strength (ranging from -0.63 to -0.66) have been detected between the initial velocity, kinetic energy, specific energy, and the presence of abrasion collar around the entry wound (р=0,03). The created conditions allow to conduct the differentiation in diagnosing the type of projectile, the identification and study of new characteristics of key elements in firearm-related injuries, and improvement in measurement accuracy. They also enhance clarity and objectivity during the execution of forensic medical examinations in cases of combat-related firearm injuries.