Skin simulants for wound ballistic investigation - an experimental study.

Gunshot wound analysis is an important part of medicolegal practice, in both autopsies and examinations of living persons. Well-established and studied simulants exist that exhibit both physical and biomechanical properties of soft-tissues and bones. Current research literature on ballistic wounds focuses on the biomechanical properties of skin simulants. In our extensive experimental study, we tested numerous synthetic and natural materials, regarding their macromorphological bullet impact characteristics, and compared these data with those from real bullet injuries gathered from medicolegal practice. Over thirty varieties of potential skin simulants were shot perpendicularly, and at 45°, at a distance of 10 m and 0.3 m, using full metal jacket (FMJ) projectiles (9 × 19 mm Luger). Simulants included ballistic gelatine at various concentrations, dental silicones with several degrees of hardness, alginates, latex, chamois leather, suture trainers for medical training purposes and various material compound models. In addition to complying to the general requirements for a synthetic simulant, results obtained from dental silicones shore hardness 70 (backed with 20 % by mass gelatine), were especially highly comparable to gunshot entry wounds in skin from real cases. Based on these results, particularly focusing on the macroscopically detectable criteria, we can strongly recommend dental silicone shore hardness 70 as a skin simulant for wound ballistics examinations.

New alginate-gelatine method for casting of staining inside firearm barrels.

Contact shots to the head often leave behind biological traces inside firearm barrels, a phenomenon of great forensic interest. Until now, the visualization and preservation of these traces presented a significant challenge, lacking a reliable method. This study addresses this gap by searching for a suitable method to extract the traces within a casting. Using alginate or gelatine as suitable materials, the results were hampered by serious adhesion issues and their extraction out of the firearm barrel was impeded. Finally, the combination of 11% gelatine with 1% alginate, introduced into the barrel around a 'central spine', succeeded to consistently produce replicable castings. Experimental contact shots displayed a distinct staining gradient from the muzzle to the rear of the barrel, as revealed through endoscopy and proved in the macroscopic casting. The technique proved effective for various common handgun barrels and successfully preserved blood and gunshot residue (GSR) patterns within the barrel. This method offers the dual benefits of visually mapping staining patterns and securing localized samples for targeted molecular genetic analysis in forensic investigations.

Children's toys no longer: a porcine model study of the lethality of modern air rifles.

AIMS: We observed modern spring-loaded air rifles reaching velocities similar to small-bore rifles, raising concerns about their potential lethality. After encountering two life-threatening thoracic injuries in our practice, we conducted a study to assess the injuries that a commonly available air rifle could cause in a porcine cadaver model. METHODS: We conducted shooting experiments from 5 and 10 metres away using a .22 calibre spring-loaded airgun, firing five shots into the anterolateral chest on the left side at both distances. Additionally, we repeated the experiment with ten shots into 10% ballistics gel behind an explanted chest wall to evaluate chest wall penetration reliability. RESULTS: Out of the ten combined shots, six resulted in lethal or potentially lethal injuries, including multiple cardiac injuries. Moreover, we observed chest wall penetration in 9 out of 10 shots, with an average penetration depth of 106mm. Non-life-threatening injuries appeared to be influenced by shot location rather than an inability to penetrate the chest wall. CONCLUSION: Our study raises significant concerns about the potential lethality of unrestricted air rifles in New Zealand. With muzzle velocities comparable to small-bore rifles, these firearms should be reconsidered in terms of regulation and possibly restricted to gun license holders.

Ballistic long bone fracture pattern: an experimental study.

When dealing with badly preserved cadavers or skeletal human remains, the assessment of death circumstances remains challenging. When forensic evidence cannot be taken from the skin and soft tissue, the information may only be deduced from more resistant elements such as bone. Compared to cranial gunshot injuries, reliable data on ballistic long bone trauma remains scarce. This study aims to define ballistic fracture characteristics in human long bones. The shaft of 16 femurs and 13 humeri from body donors was perpendicularly shot with a 9-mm Luger full metal jacket bullet at an impact velocity of 360 m/s from a distance of 2 m. Some bones were embedded in Clear Ballistics Gel®, and some were shot without soft tissue simulant in order to better visualise the fracture propagation on the high-speed camera. The fractures were examined macroscopically and compared between the sample groups. We consistently found comminuted fractures with a stellate pattern. Fracture details were classified into entrance, exit and general characteristics. For some traits, we detected different occurrence values in the group comparison. The results indicate that some of the traits depend on bone properties such as shaft diameter, bone length and cortical thickness. The presence of ballistic gel also influenced some fracture traits, emphasising the relevance of soft tissue simulant in osseous gunshot experiments. This study revealed new insights in the detailed fracture pattern of human long bones. These may serve as guidelines for the identification and reconstruction of gunshot trauma in human long bones.

Review of non-penetrating ballistic testing techniques for protection assessment: From biological data to numerical and physical surrogates.

Human surrogates have long been employed to simulate human behaviour, beginning in the automotive industry and now widely used throughout the safety framework to estimate human injury during and after accidents and impacts. In the specific context of blunt ballistics, various methods have been developed to investigate wound injuries, including tissue simulants such as clays or gelatine ballistic, physical dummies and numerical models. However, all of these surrogate entities must be biofidelic, meaning they must accurately represent the biological properties of the human body. This paper provides an overview of physical and numerical surrogates developed specifically for blunt ballistic impacts, including their properties, use and applications. The focus is on their ability to accurately represent the human body in the context of blunt ballistic impact.

Two Bullet Wounds, One Bullet: The Atypical Fragmentation of a .223 Caliber Ammunition.

ABSTRACT: As the fifth leading cause of death in individuals aged 1 to 64 years in the United States, forensic pathologists frequently encounter firearm-related deaths and are trained to approach these cases by utilizing information from the investigation, radiographs, and autopsy findings to discern the logical sequence of events that lead to death. We also emphasize the importance and utility of various factors such as bullet wound characteristics, type of ammunition used, and type of tissues involved in a forensic pathologist's determination of events and in medicolegal investigations. However, the unusual presentations of firearm-related deaths can cause confusion and even frustration when there are contradicting circumstances or findings at work. We present the case of a 61-year-old woman with an atypical pattern of 2 distinct irregular entrance gunshot wounds determined to be caused by a single projectile.

Effects of kinetic energy and firearm-to-target distance on fracture behavior in flat bones.

This research implements a fractographic approach to investigate the relationships between kinetic energy, firearm-to-target distance, and various aspects of fracture behavior in gunshot trauma. Gunshot experiments were performed on pig scapulae (n = 30) using three firearms generating different muzzle (initial) kinetic energies, including a 0.32 pistol (103 J), 0.40 pistol (492 J), and 0.308 rifle (2275 J). Specimens were shot from two distances: 10 cm (n = 15) and 110 cm (n = 15). Features evaluated in fractographic analysis such as cone cracks, radiating cracks, crack branching points, and circumferential cracks could be easily identified and measured in flat bones and allowed for statistical comparison of crack propagation behavior under different impact conditions. Higher-energy bullets produced more radiating cracks, more crack branching points, and longer fracture lengths than lower-energy bullets. Distance had no significant effect on fracture morphology at the distances tested. That quantitative measures of crack propagation varied with energy affirms that kinetic energy transfer is important in determining the nature and extent of fracture in gunshot wounds and suggests it may be possible to infer relatively high- versus relatively low-energy transfer using these features. Ranges obtained with the three firearms exhibited considerable overlap, however, indicating that other variables such as bullet caliber, mass, and construction influence the efficiency of energy transfer from bullet to bone. Therefore, fracture morphology cannot be used to identify a specific firearm or to directly reconstruct the muzzle (initial) kinetic energy in forensic cases.

Extracorporeal bullet trajectory determination from scanned phantoms with bullet defects.

Shots with two different calibres (0.32 Auto and 9 mm Luger) were fired through phantoms that simulated human torsos, mounted on undercarriages with witness panels. The perforated phantoms were scanned with computed tomography (Siemens) using 80 kV and 140 kV and a slice thickness of 1 mm. The intracorporeal trajectories in the phantoms were compared to the known extracorporeal trajectories, derived from the perforations in witness panels. The discrepancy between the intracorporeal and extracorporeal trajectories, denoted as the absolute angle, was calculated for the trajectories before (front) and after (rear) the phantoms. Mean absolute angles at the front were lower than at the rear (2.27° vs. 4.54°) and the difference was statistically significant (p < 0.001). The results of the study imply that the line between the entrance and the exit wound in a scanned victim can be extended to the extracorporeal bullet trajectory leading towards the entrance wound. The absolute angles presented in this study give an impression of the expected errors with the two calibres. This can be helpful in shooting investigations to assess the position of the shooter from entrance and exit wounds in a scanned victim.

Impact Location Dependence of Behind Armor Blunt Trauma Injury Assessed Using a Human Body Finite Element Model.

Behind armor blunt trauma (BABT), resulting from dynamic deformation of protective ballistic armor into the thorax, is currently assessed assuming a constant threshold of maximum backface deformation (BFDs) (44 mm). Although assessed for multiple impacts on the same armor, testing is focused on armor performance (shot-to-edge and shot-to-shot) without consideration of the underlying location on the thorax. Previous studies identified the importance of impacts on organs of animal surrogates wearing soft armor. However, the effect of impact location was not quantified outside the threshold of 44 mm. In the present study, a validated biofidelic advanced human thorax model (50th percentile male) was utilized to assess the BABT outcome from varying impact location. The thorax model was dynamically loaded using a method developed for recreating BABT impacts, and BABT events within the range of real-world impact severities and locations were simulated. It was found that thorax injury depended on impact location for the same BFDs. Generally, impacts over high compliance locations (anterolateral rib cage) yielded increased thoracic compression and loading on the lungs leading to pulmonary lung contusion (PLC). Impacts at low compliance locations (top of sternum) yielded hard tissue fractures. Injuries to the sternum, ribs, and lungs were predicted at BFDs lower than 44 mm for low compliance locations. Location-based injury risk curves demonstrated greater accuracy in injury prediction. This study quantifies the importance of impact location on BABT injury severity and demonstrates the need for consideration of location in future armor design and assessment.

Observing the fragmentation of two expanding bullet types and a full metal-jacketed bullet with computed tomography-a forensic ballistics case study.

Computed tomography (CT) may have a crucial role in the forensic documentation and analysis of firearm injuries. The aim of this forensic ballistics case study was to explore whether two types of expanding bullets and a full metal-jacketed bullet could be differentiated by inspecting bullet fragments and fragmentation pattern in CT. Three types of .30 caliber bullets (full metal-jacketed Norma Jaktmatch, expanding full-copper Norma Ecostrike, and expanding soft-point Norma Oryx) were test fired from a distance of 5 m to blocks of 10% ballistic gelatine. CT scans of the blocks were obtained with clinical equipment and metal artifact reduction. Radiopaque fragments were identified and fragmentation parameters were obtained from the scans (total number of fragments, maximum diameter of the largest fragment, distance between entrance and the closest fragment, length of the fragment cloud, and maximum diameters of the fragment cloud). The fragmentation patterns were additionally visualized by means of 3D reconstruction. In CT, the bullet types differed in several fragmentation parameters. While the expanding full-copper bullet Ecostrike left behind only a single fragment near the end of the bullet channel, the soft-point Oryx had hundreds of fragments deposited throughout the channel. For both expanding bullets Ecostrike and Oryx, the fragments were clearly smaller than those left behind by the full metal-jacketed Jaktmatch. This was surprising as the full metal-jacketed bullet was expected to remain intact. The fragment cloud of Jaktmatch had similar mediolateral and superoinferior diameters to that of Oryx; however, fragments were deposited in the second half of the gelatine block, and not throughout the block. This case study provides a basis and potential methodology for further experiments. The findings are expected to benefit forensic practitioners with limited background information on gunshot injury cases, for example, those that involve several potential firearms or atypical gunshot wounds. The findings may prove beneficial for both human and wildlife forensics.

The muzzle to target distance -staining inside different parts of the firearm barrel.

Biological traces inside firearm barrels were observed as a result of contact shots to the head. The present study was conducted to investigate the influence of the muzzle to target distance on staining inside the anterior and posterior part of firearm barrels. Ninety-nine shots were fired to so-called reference cubes (10% gelatine, 12 cm edge length, embedded paint-blood-pad) using three current handguns. Shot range was varied from contact to 50 cm distance. High-speed cameras recorded external backspatter. Endoscopic examination assessed visible staining along the barrel. Each two swabbings were gathered from the anterior and the posterior part of the barrel. The first swabs were submitted to quantitative PCR, the second ones to DNA-RNA-co-extraction. Thorough mechanical and chemical cleaning was performed to avoid any contamination which was controlled by negative zero swabs after each cleaning. In single shots up to 50 cm distance, minimal, but DNA-positive sporadic traces were detected inside the barrel in vicinity of the muzzle. Visible complex staining varying in extent was observed in the anterior barrel part for 10 cm or less distance in dependence of the calibre. The posterior part showed detectable traces only after close range shots (< 5 cm). Generally staining inside the barrel decreased from the muzzle to the rear end, which correlated with the yield of DNA. Some contact shots did not cause any staining in the posterior part of the barrel despite massive external backspatter. Blood-specific miRNA was primarily found where DNA was detected. This experience encourages to take a second swab for RNA analysis. The amount of nucleic acids in the barrel at varying muzzle to target distances is subject to large variations between individual shots and therefore appears not suitable for a reliable determination of the shot distance in a particular case on its own. Instead, shot range estimation should also take into account morphology and distribution of traces inside the barrel.

Cutaneous skin defects overlying tangential gunshot wounds: A case series.

In examining deaths resulting from gunshot wounds, it is important to describe the wound pathway created by the projectile. Forensic pathologists must identify all entrance and exit wounds and account for all projectiles. Occasionally, confusion arises as to whether a skin defect represents an entrance wound or not, an exit wound, or some other type of wound. Herein, we propose the descriptor "bullet track skin defect" as a formal description for a superficial skin defect created along the pathway of a projectile within the body. Specifically, we define the "bullet track skin defect" as a partial- or full-thickness skin defect produced by a projectile traveling beneath the skin in a relatively tangential fashion as part of a wound pathway within the body. It is somewhat analogous to a traditional graze or superficial tangential wound, wherein the projectile traveling outside the body strikes the skin tangentially from above, without entering the body. However, the projectile is already traveling within the body with the bullet track skin defect, disrupting the skin tangentially from below rather than from above, without exiting the body. Although these defects are not a common presentation of gunshot wounds, they are certainly not rare. With this case series, we suggest that such defects may be referred to as "bullet track skin defects." Alternative language that can substitute for "bullet track skin defects" includes "bullet track skin wounds" or "bullet track cutaneous defects."

[Features of coarse calico damage by hollow-point bullets of ammunitions to a 12-gauge fire smoothbore weapon (12×70) under the conditions of remote shooting distance]. / Osobennosti povrezhdeniya byazevoi tkani ekspansivnymi pulyami patronov k ognestrel'nomu gladkostvol'nomu oruzhiyu 12-go kalibra (12×70) v usloviyakh neblizkoi distantsii vystrela.

The article presents the experimental study results of damaged clothes imitators' (coarse calico) features in consequence of shot by ammunitions with hollow-point bullet from a 12-gauge fire smoothbore weapon (12×70). The generation mechanism of coarse calico damage during wound of underlying biological human body's imitator by bullet and the factors influencing on mentioned process have been clarified using high-speed video recording.

[Distribution features of gunshot residue from hunting Steyr Mannlicher AUG-Z3 carbine on targets]. / Osobennosti raspredeleniya na mishenyakh produktov vystrela iz okhotnich'ego karabina Steyr Mannlicher AUG-Z3.

OBJECTIVE: To study the morphology of distribution of shot factors on white targets made of coarse calico at different distances. MATERIAL AND METHODS: The study was conducted on 57 experimental damages of targets made of cotton fabric, caused by shots from hunting self-loading Steyr Mannlicher AUG-Z3 carbine of.223 Rem caliber. The number of experimental firings equal 19 was done by 3 shots at the distance from close range to 250 cm. The examination of shot targets was carried out using the visual, metric, stereoscopic (Leica 125M microscope) methods, in ultraviolet rays (LUMATEC SUPERLITE M Series light). RESULTS: The nature and morphology of distribution of gunshot residue on targets' surfaces made it possible to establish close range firing zones. The nature in which soot is deposited during shot under the conditions of point-blank range and in the first zone of close range (up to 8 cm) allows to establish the position of weapon's transverse plane relative to the target basing on a specific blowout of a gas-powder jet from special design of flame arrestor. The performed experimental shooting from hunting self-loading Steyr Mannlicher AUG-Z3 carbine made it possible to determine the metric and morphological characteristics of the close range firing zones: 1 zone is equal a distance up to 8 cm; 2 zone - up to 30 cm; 3 zone - up to 100 cm from muzzle of weapon. The design features of Steyr Mannlicher AUG-Z3 carbine's flame arrestor allow to identify the type of weapon according to the morphological pattern of target's damage. The complex of obtained data makes it possible to determine the firing distance with high accuracy.

Heridas por proyectil de arma de fuego. Atipicidad en orificios de entrada y el fenómeno de ''cola de cometa": Reporte de caso / Gunshot wounds. Atypicality in entry holes and the "comet tail" phenomenon: Case report

El análisis de los orificios de entrada por proyectil de arma de fuego en una autopsia médico legal representa un importante papel en la determinación de la forma y causa de muerte en casos relacionados con armas de fuego. Su valoración puede proporcionar información valiosa sobre las características del arma utilizada, la distancia entre el arma de fuego y la víctima, entre otros factores que contribuyen a la investigación. El fenómeno de ''cola de cometa" observado en ciertos orificios de entrada es poco frecuente y conocido. Por lo anterior, el objetivo de este artículo es investigar las características y mecanismos de producción de los orificios de entrada con este fenómeno, proporcionando información sobre su formación, las posibles implicaciones y consideraciones médico legales a tomar en cuenta para su diagnóstico de esta causa de muerte. Se presenta un reporte de caso que destaca la descripción del fenómeno de ''cola de cometa" en una investigación forense de la vida real, proporcionando información valiosa sobre su utilidad y potencial para mejorar la precisión del análisis de heridas de bala. Se realizó revisión de artículos científicos, sobre orificios de entrada en heridas por proyectil de arma de fuego con el fenómeno de ''cola de cometa".

The analysis of firearm projectile entry holes in a medicolegal autopsy plays an important role in determining the manner and cause of death in cases involving firearms. The assessment can provide valuable information about the characteristics of the weapon used, the distance between the firearm and the victim, among other factors that contribute to the investigation. The ''comet tail" phenomenon observed in certain entry holes is rare and well known. Therefore, the objective of this article is to investigate the characteristics and mechanisms of production of the entrance orifices with this phenomenon, providing information about their formation, the possible implications, and medical-legal considerations to be taken into account for the diagnosis of this cause of death. A case report is presented highlighting the description of the ''comet tail" phenomenon in a real-life forensic investigation, providing valuable insight into its utility and potential to improve the accuracy of gunshot wound analysis. A review of scientific articles was carried out on entry holes in gunshot wounds with the "comet tail" phenomenon.

[War wounds and ballistics]. / Plaies de guerre et balistique.

Ballistic wounds, which historically concerned military populations, now also affect civilian practice. Terrorist attacks, urban violence and certain accidents have brought them into the daily routine of some French hospitals. Their frequency fully justifies the need for every health-care professional to be aware of the major issues involved in their management. In this section, we will describe the various penetrating ballistic wounds and their specific features. We will also rectify certain preconceived ideas that should not be peddled by healthcare professionals, in order to maintain a high standard of care.

[Ballistic injury, decaying wounds: the nurse at the heart of the long rehabilitation process]. / Lésion balistique, plaies délabrantes : l'infirmier au cœur du long parcours de réhabilitation.

Ballistic injuries are disabling. Its functional impact is determined by its trajectory. Whether the injury affects a limb that could jeopardize its preservation, visceral lesions or craniocerebral and vertebro-medullary wounds, the nurse is at the heart of multidisciplinary care to limit and compensate for the after-effects. Directed healing, appropriate analgesia, settling in, technical training for this new, modified body (stoma, self-catheterization, appliances, etc.) and support in accepting the injury are all part of the nurse's role in helping the injured person rebuild his or her life.

A Novel Paradigm to Develop Regional Thoracoabdominal Criteria for Behind Armor Blunt Trauma Based on Original Data.

INTRODUCTION: For behind armor blunt trauma (BABT), recent prominent BABT standards for chest plate define a maximum deformation distance of 44 mm in clay. It was developed for soft body armor applications with limited animal, gelatin, and clay tests. The legacy criterion does not account for differing regional thoracoabdominal tolerances to behind armor-induced injury. This study examines the rationale and approaches used in the legacy BABT clay criterion and presents a novel paradigm to develop thoracoabdominal regional injury risk curves. MATERIALS AND METHODS: A review of the original military and law enforcement studies using animals, surrogates, and body armor materials was conducted, and a reanalysis of data was performed. A multiparameter model analysis describes survival-lethality responses using impactor/projectile (mass, diameter, and impact velocity) and specimen (weight and tissue thickness) variables. Binary regression risk curves with ±95% confidence intervals (CIs) and peak deformations from simulant tests are presented. RESULTS: Injury risk curves from 74 goat thorax tests showed that peak deflections of 44.7 mm (±95% CI: 17.6 to 55.4 mm) and 49.9 mm (±95% CI: 24.7 to 60.4 mm) were associated with the 10% and 15% probability of lethal outcomes. 20% gelatin and Roma Plastilina #1 clay were stiffer than goat. The clay was stiffer than 20% gelatin. Penetration diameters showed greater variations (on a test-by-test basis, difference 36-53%) than penetration depths (0-12%) across a range of projectiles and velocities. CONCLUSIONS: While the original authors stressed limitations and the importance of additional tests for refining the 44 mm recommendation, they were not pursued. As live swine tests are effective in developing injury criteria and the responses of different areas of the thoracoabdominal regions are different because of anatomy, structure, and function, a new set of swine and human cadaver tests are necessary to develop scaling relationships. Live swine tests are needed to develop incapacitation/lethal injury risk functions; using scaling relationships, human injury criteria can be developed.

[Determination of the transfer of composite obstacle material by a gunshot projectile]. / Ustanovlenie fakta perenosa ognestrel'nym snaryadom veshchestva pregrady iz kompozitnykh materialov.

The aim of the experimental study was to establish the transfer of obstacle's composite material (foamed concrete, magnesite concrete, porcelain stoneware, galvanized sheet steel, wood particle board) by the gunshot projectile on firing by rounds sized 5.45´39 from the special shortened Kalashnikov assault rifle (AKS-74U). The shots were fired through various types of obstacles on different parts of animal carcasses from a distance of 3-5 m. Bullets and their fragments, extracted from the bullet trap or the biological target tissue, after appropriate processing were studied by «Leika M125¼ microscope, «Hitachi FlexSem1000 II¼ scanning electronic microscope and «Bruker Quantax 80¼ energy-dispersive X-Ray spectrometer. The conducted light microscopy of gunshot projectiles' fragments, which had overcome the obstacle, revealed the presence of a specific deformation of the bullet head at its penetration of each type of investigated obstacles. Scanning electron microscopy (SEM) and energy-dispersive X-Ray analysis (EDX) have revealed in each case the presence of obstacle particles overlaying over the entire surface of either deformed bullets or their fragments. The performed experimental study has shown that it is possible to establish the fact of person's gunshot injury through a composite obstacle by the use of SEM/EDX.