Gunshot wounds in parenchymatous organs: the morphology mainly depends on the physical properties of the affected tissues.

In contrast to gunshot wounds in skin and bone, the medico-legal literature pays little attention to the appearance of bullet penetration sites in abdominal organs. It was only in 1983 that Metter and Schulz published an article entitled "Morphological features of gunshot wounds in the liver and spleen." According to their observations, the organs in question showed stellate tears at the bullet penetration sites resembling skin wounds from contact shots to body regions having a bony support. The study presented simulated the real conditions by means of test shots to composite models consisting of porcine organs embedded in ballistic gelatin. The ammunition used was pistol cartridges 9 mm Luger with full metal jacket round nose bullets. The shots were video-documented with a high-speed camera in order to record the bullet's travel through the target. In addition, the composite models fired at underwent CT examinations followed by a macroscopic assessment of the organs. The study confirmed the findings of Metter and Schulz with regard to the star-like appearance of gunshot wounds in the liver and spleen. Likewise, the kidney showed radiating tears originating from the bullet path, whereas the wound track in pulmonary tissue was tube-shaped and lacked additional cracks. The varying wound patterns in parenchymatous organs can reasonably be explained as a consequence of the respective viscoelastic tissue properties

Gunshot-related displacement of skin particles and bacteria from the exit region back into the bullet path

In previous studies, it was shown that there is a gunshot-related transport of skin particles and microorganisms from the entrance region into the depth of the bullet path. The present study deals with the question of whether gunshots may also cause a retrograde transport of skin particles and microorganisms from the bullet exit region back into the bullet path. For this purpose, we used a composite model consisting of rectangular gelatin blocks and pig skin. The skin pieces were firmly attached to the gelatin blocks on the side where the bullet was to exit. Prior to the test shots, the outer surface of the pig skin was contaminated with a thin layer of a defined bacterial suspension. After drying the skin, test shots were fired from a distance of 10 m using cartridges calibre .38 spec. with different bullet types. Subsequent analyses showed that in all shots with full penetration of the composite model, the bullet path contained displaced skin particles and microorganisms from the skin surface at the exit site. These could be regularly detected in the distal 6-8 cm of the track, occasionally up to a distance of 18 cm from the exit hole. The distribution of skin particles and microorganisms is presented and the possible mechanism of this retrograde transport is discussed

Effect of shortening the barrel in contact shots from rifles and shotguns

In a suicidal gunshot fired to the chest from a carbine, the barrel of which had been shortened to half its original length, an unexpectedly large degree of destruction of the anterior thoracic wall with extensive undermining of the subcutis was found. This phenomenon was investigated for reconstructive purposes by firing test shots from two different long guns (caliber 7.92 x 57 repeating rifle with full-jacketed pointed bullet and caliber 12/70 single-barreled shotgun with shotgun slug) into blocks of soap (38 x 25 x 25 cm). The contact shots were fired before and after shortening the barrels (repeating rifle from 60 to 30 cm and single-barreled shotgun from 72 to 36 cm). The volume of the cavities in the simulant was visualized three-dimensionally with the help of a multislice computed tomography (CT) scanner and calculated sectionally. With the repeating rifle and the single-barreled shotgun, the shots from the sawed-off barrels produced significantly larger cavity diameters in the first section of the bullet track. This effect is attributable to the fact that, with a shortened barrel, the gas pressure at the muzzle is higher, thus, leading to increased expansion in the initial part of the wound track in contact shots