A "skin-skull-brain model" for the biomechanical reconstruction of blunt forces to the human head

In order to create and study blunt force wound morphology, a "skin-skull-brain model" had to be designed which would make the laboratory reproduction of a blunt force injury to the head possible. During the evaluation of the "skin-skull-brain model", it was possible to show that injuries inflicted to this model are fully comparable to the morphology of equivalent real blunt forces injuries to humans. Utilization of the "skin-skull-brain model" presents some significant advantages: the model is inexpensive, easy to construct, instantly available for use, and eliminates ethics conflicts. The main advantage of such a model is, in comparison with biological substances, the high reproducibility of experimentally inflicted traumas.     

A study of the morphology of gunshot entrance wounds, in connection with their dynamic creation, utilizing the "skin-skull-brain model"

The goal of this study was to document the dynamic effects created within, and the developing mechanisms of a gunshot entrance wound to the skin utilizing high-speed photography and the "skin-skull-brain model". The high-speed photography was taken with an Imacon 468/Hadland-Photonics camera. Full metal jacketed, 9 mm Luger projectiles were fired at the target model from a distance of 10 m. During the evaluation of the "skin-skull-brain model", it was possible to show that injuries inflicted to this model are fully comparable to the morphology of equivalent real gunshot entrance wounds. It has been possible to document and study the dynamic process of the "bullet-skin-interaction" in the gunshot entrance wound. The development of the morphologic terms of the entrance wound are discussed. In combination with high-speed photography, this "skin-skull-brain model" is a perfect tool for the documentation and the study of the dynamic development of gunshot entrance wounds in the skin.     

The dynamic development of the muzzle imprint by contact gunshot: high-speed documentation utilizing the "skin-skull-brain model"

Many contact gunshots produce a muzzle imprint in the skin of the victim. Different mechanisms have been discussed in literature as being responsible for the creation of the muzzle imprint. Experimenting upon the synthetic non biological skin-skull-brain model, our goal was to document and study the creation of the muzzle imprint with the aid of high-speed photography. In our experiments, we could document with our high-speed photography (at exposure rates in the range of nanoseconds) the bulging, the pressing against the muzzle, and the splitting of the artificial skin. Furthermore, it was possible to photographically record the back pattern of synthetic tissue particles. And, the soot and gunpowder cavity could be reproduced experimentally. In conclusion the experiments completed with the skin-skull-brain model, using high-speed photography for documentation, show the promising possibilities of experimental ballistics with body models.     

High-speed documented experimental gunshot to a skull-brain model and radiologic virtual autopsy

The authors documented and evaluated experimental gunshots to a skull-brain model with high-speed photography and subsequent radiographic examination for comparison of the morphologic findings in the model. The artificial skull was a polyurethane ball constructed in layers, with a porous diploe sandwiched between a tabula externa and a tabula interna. The brain itself was simulated with gelatin 10% at 4 degrees C, a material well known in wound ballistics. Gunshots were fired at the model from a distance of 10 m and documented with high-speed photography (up to 50 million frames/sec). Subsequently, a complete examination of the artificial skull was performed, including spiral computed tomography (with two-dimensional and three-dimensional reconstructions) and classic skull autopsy. The high-speed photographs clearly showed the dynamic development of the skull fracture system from an external perspective. The subsequent radiographic examination of the entire head volume created two-dimensional reformations in any plane and three-dimensional reconstructions of the gunshot injury of the polyurethane skull-brain model, especially the wound channel and the fracture system. Thanks to the model and high-speed photographs, the dynamic development of the morphology of a gunshot wound could be documented and studied. The data from computed tomography, using two-dimensional and three-dimensional postprocessing with a perspective view, were very similar to those from classic head autopsy, but derived in a hands-off and nondestructive manner. This examination method leads the way to radiographic digital autopsy or virtual autopsy.     

Forensic medical expert evaluation of gunshot injuries of brain skull

Forensic medical experts are offered a set of morphological signs which help identify the gunshot origin of a skull injury, identify which of the injuries is the inlet and which is the outlet, specify the direction of the shot and succession of formation of injuries in cases with several shots. The author suggests evaluating a gunshot wound in the head with due consideration for the mechanisms of its formation. From a complex of signs of a gunshot injury to the brain skull he singles out the tissue defect with a conical channel and the edge of bone defect, additional injury to the external compact plate near the inlet, and type, number, and location of the radial and concentric cracks. Analysis of the morphology of the above listed signs of gunshot injuries to the skull notable extends the potentialities of forensic medical expert evaluation in cases with gunshot injuries.     

Secondary combined suicide viewed by the wife]

A 47-year-old man was found dead at the bottom of a wall outward the door of the cellar of his house. Preliminary physical examination at the scene of the death revealed a laceration of the scalp, an incised wound in front of the neck and several stab wounds in the left chest penetrating through the clothing. Questioned by the police his wife told that her husband who suffered from severe depression had inflicted the incised and the stab wounds himself, had made an unsuccessful attempt at self-strangulation and had finally jumped down from the wall beside the stairs declining to the cellar of their house. As the circumstances of the scenario were suspicious and as the pattern of injuries arose doubts concerning self-infliction homicide was taken into consideration as well. Autopsy showed additional hesitation marks adjacent to the left end of the incised wound in front of the neck. The stab wounds of the chest were restricted to the region of the heart and displayed only minimal penetration of the chest-wall, findings characteristic of self-infliction. As a consequence the manner of death could be determined as prolonged suicide, and exact reconstruction was possible with the help of the wife's testimony.     

Postmortem bite injuries cause by a domestic cat]

A 70-year-old farmer was found dead in front of a barn. The emergency doctor did not note any significant findings at the external examination of the body. When the corpse was picked up by the undertaker, he noticed facial injuries. Several domestic cats were strolling around the barn at this time. External examination by a forensic pathologist revealed both sharp and crenated wound margins around the removed ear with punctured stabs adjacent to the mutilation. Further small perforating but not mutilating skin lesions were found also on other parts of the face. Given the typical morphology of the skin lesions and the observation of cats at the death scene, it is concluded that the injuries were inflicted by at least one domestic cat. In the forensic literature, reports on depredation of human corpses by cats are rare. To our knowledge, this is the first case report of outdoor cat depredation in the early postmortem interval. The case shows that domestic cats feed on human corpse even if other food is available.     

Site, number and depth of wounds of the scalp in falls and blows--a contribution to the validity of the so-called hat brim rule

The sites, numbers and lengths of wounds of the skin of the scalp and head caused by blunt injuries (falls from standing position, falls downstairs, blows) in an autopsy series. Analysis of the localization, length and number of wounds located at the head in 305 autopsy cases of falls from a standing position (203 cases), falls downstairs (51 cases) and blows with relatively long materials (51 cases). For the distinction between falls and blows, among several other aspects the so-called rule of the hat-brim-line is described: in cases of falls from a standing position down to a flat bottom, contusions can be expected in or near a line which represents the greatest horizontal circumference of the skull, whereas in cases of blows the contusions lay above this area. Although such a tendency was found in our material, a rule could not be confirmed: only approximately 55% of the wound due to blows were above this line, and in cases of falls from a standing position ca. 1/3 of the wounds were above this area. Only in the (dorso-frontal and parietal) region "top of the head" contusions due to falls from a standing position were quite uncommon. The mean length and length distribution of wounds in the hat-brim-zone was not different between the 3 causes of injuries; in positions above this, wounds due to blows were longer compared to those by falls. In falls from a standing position, only exceptionally more than 1 wound was found, whereas in cases of homicide several or many wounds were common. Single wounds due to blows were only found in cases, in which the victims were knocked down but not killed by blunt forces, and death was caused by other methods (e.g. strangulation or stabbing).     

Vital animal predation of the genital region caused by a mongrel dog

A 79-year-old man, who was in a helpless situation due to cardiac decompensation, suffered dog bite injuries on the left thigh and in the genital region while still alive. Two extensive soft-tissue defects with contused and bruised wound edges were surrounded by multiple slit-like skin lesions. The outer genitals were almost completely missing. Because of surgical emergency treatment, molecular biological investigations were no longer possible. Therefore, the cause of the bite injuries had to be determined solely on the basis of the documented morphology of the wounds.     

Release of proteinase inhibitors as a vital reaction in the early post-traumatic interval

In a pilot study paraffin-embedded sections of open skin wounds (stab and slash wounds, lacerations) were investigated to determine the presence of a vital reaction. Granulocytes were detected by naphthol AS-D chloroacetate esterase, the enzyme "lysozyme", and eight proteinase inhibitors by the indirect immunoperoxidase method. The tissue specimens were taken from consecutive autopsy material. The survival time could be determined in 14 cases (10-165 min) and was unknown in 12 other cases of sudden death due to injury of the major vessels or heart. The controls were cases with injuries inflicted after and cases of sudden death due to massive blunt trauma served death. In vital injuries, accumulations of proteinase inhibitors, particularly alpha-2-macroglobulin and alpha-1-antichymotrypsin, were demonstrable in the corium parallel to the wound surface. In comparison, the reaction of proteinase inhibitors that neutralize only enzymes participating in blood coagulation or complement activation (C1-esterase inhibitor and protein C) was absent or weak. Protein accumulation was observed only sporadically in cases of sudden death and never in cases with wounds inflicted after death. No relationship could be established between semiquantitatively estimated staining and survival time. Granulocytes and lysozyme were first observed in the corium after a survival time of more than 60 min.     

Skin and soft tissue artifacts due to postmortem damage caused by rodents.

Five cases of postmortem bite-injuries inflicted by rodents are presented (five males between 41 and 89 years; three cases caused by mice, one case by rats, one case of possible mixed rodent activity by rats and mice). The study presents a spectrum of phenomenological aspects of postmortem artifacts due to rodent activity to fresh skin and soft tissue: the majority of the injuries have a circular appearance. The wound margins are finely serrated with irregular edges and circumscribed 1-2 mm intervals within, partly showing protruding indentations up to 5 mm. Distinct parallel cutaneous lacerations deriving from the biting action of the upper and lower pairs of the rodents incisors are diagnostic for tooth marks of rodent origin but cannot always be found. No claw-induced damage can be found in the skin beyond the wound margins. Areas involved in the present study were: exposed and unprotected parts of the body, such as eyelids, nose and mouth (representing moist parts of the face); and the back of the hands. Postmortem rodent activity may occasionally be expected on clothed and therefore protected parts of the body. The phenomenon of postmortem rodent activity to human bodies can be found indoors especially under circumstances of low socioeconomic settings; outdoors this finding is particularly observed among fatalities among homeless people.     

Determination of questionable suicide as a homicide by studies of criminal stains

In a woman found dead with cuts on both arms in a domestic sauna plastered with blood were assumed next to a bleed to death. The question self-infliction or by a third party of arm injuries could not be decided. By investigation of blood traces only could be clarified the cause of death. The husband had strangled his wife and inflicted several cuts on both arms with a razor blade to simulate suicide. Afterwards, he also inflicted several cuts on himself with a razor blade with the intention of suicide. He survived these injuries.     

Aiming at the chest, but hitting the back

Gunshot injuries in the back may suggest the unjustified use of firearms. A wound in the back inflicted by a firearm should not automatically imply that the shooter aimed at the back. A previous study demonstrated that it is possible for men to turn their trunk faster than it takes for a shooter to fire or throw a hand-operated weapon. With a high speed motion camera the authors were able to demonstrate that it is also possible for women to turn their trunk fast enough, so that a shot in the back could have been aimed at the front of the body. This conclusion is also likely to apply to hand-operated or thrown weapons, since the velocity of their projectiles is considerably lower than that of firearms.     

Shooting Through Clothing in Firearm Suicides

Abstract: There is a longstanding empirical rule that people who commit suicide rarely shoot through their clothing, but rather put it aside to expose the nude skin. Signs of shots through clothing have always been considered suspicious, raising presumptions of the presence of an abettor. Our report, based on a retrospective study of fatal suicidal firearm injuries from the years 1980 to 2007, points out that suicide victims only rarely remove clothing from the site of the future entry wound. The report covered 43 cases with fatal gunshot wounds in the area of the thorax, with only four persons (9%) removing the clothing present in the area of the subsequent self‐inflicted wound. Defects present on the clothing of a victim cannot, therefore, be understood as an absolute criterion for disproving the possibility of suicide, and nor do they necessarily indicate an unfortunate accident or homicide. If, however, the suicide victim removes the clothing from the area of the future wound, then this is almost always an indication of suicide.     

The evaluation of a synthetic long bone structure as a substitute for human tissue in gunshot experiments

Our goal was to compare experimental gunshot wounds in our non-biological bone model with similarly created wounds in swine bones, and evaluate the results. The design of the synthetic (polyurethane) bone was patterned after human bone structure, with a compact outer layer covering a porous inner layer. Ordnance gelatin, as substitute bone marrow, was injected into the bone's hollow core. To simulate the periostium, the bone was covered with a layer of latex. Then the bone was embedded in gelatin used to simulate surrounding soft tissue. For comparison, fresh swine bones were also embedded in gelatin, and fired upon under the same guidelines. All gunshots were high-speed filmed. In our experimental study, gunshot wounds to swine bones, and to our synthetic, non-biological bones were compared. The results (the comparison between the biological swine bones and the non-biological model bones) in regard to the following points are absolutely equal: the loss of velocity and energy after striking bone, bone fragmentation, bullet deformation, and the penetrating wound channel. Continuing studies with our synthetic bone model will bring about an even greater understanding of the mechanisms of "bullet-bone interaction". For this reason, we have extended our variety of bone models to include other skeletal structures such as skull, spine, pelvis and flat bones for further gunshot experiments.     

Classification of skin injuries inflicted by the teeth of the carnivorous animals

The current approaches to the classification of skin injuries inflicted by the teeth of the carnivores on the human body are discussed. The new morphological classification is proposed taking into consideration the current views of the mechanisms underlying the formation of tooth marks on the integumental tissues of the victims of attacks by carnivorous animals. Morphological characteristics of skin injuries are briefly described in the framework of the new classification.     

The hydrodynamic effect of gunshots in cranial explosive shots

Case report on five fatal gunshot injuries in which discharge of the cranial contents had occurred owing to a skull blast. Despite an appreciable explosive action with destruction of the bony cranium, the brains were not completely destroyed. In analogy to the "Kr?nlein shot", comparative reflections were made concerning wound ballistics. The case reports show that injury patterns resembling "Kr?nlein shot" may arise in cranial blast shots in rare cases despite destroyed projectile parts and even in a mouth shot.     

An unusual case of child head injury by coat hanger*

Traumatic brain injury is the leading cause of morbidity and mortality among children suspected of child abuse. Penetrating cranio-facial injuries are generally rare in the pediatric age group and are caused by both accidental and inflicted mechanisms. We report an unusual case of a 2-year-old female who was admitted to a pediatric emergency room with an industrial stainless steel coat hanger impaled in her skull. Pertinent clinical forensic medicine examination, coupled with home inspection and interviews by the local law enforcement, revealed a horrible episode of domestic violence.