The differential diagnosis and the identification importance of the track of the heel of stabbing-cutting weapons in skin wounds

Data on 123 cut-stab wounds and 52 knives were examined in the course of medicolegal expert evaluation. It was found that 30 knives possessed heels which could have two forms: symmetric and asymmetric. Heel traces were seen in 16 expert evaluations (34%) in 31 wounds (25.2%) and in some of them particular features of knife blade heel were represented. Differences between butt end and heel trace according to series of signs were noted.     

Morphologic, experimental-comparative investigation as an identification of the injuring instrument method

Aiming to identify the injuring tool characteristics and the tool itself morphologic, experimental-comparative investigations of the skin wound, rib and cartilage injuries taken during the autopsy are performed. During 1995-2004, 489 investigations were performed for this purpose. In 418 cases, knives were submitted for identification of the specific injuring tool (in total-835 knives). In 205 cases the investigation included not only skin wounds, but also the injured rib cartilages. Identification investigations were performed by investigating both the skin wounds morphologic characteristics and dynamic traces-trails in the rib cartilage tissue left by the micro relief of the knife blade edge. In the case of the investigated and experimental skin wounds characteristics coincidence the experimental and comparative dynamic traces investigation was performed when the traces were suitable for the tool identification purposes. In the case of the investigated and experimental skin wounds, dynamic traces coincidence, the totality of the coincided characteristics was considered individual. In those cases, the conclusion included the fact that the injury had been made by a particular knife. According to our data during 1995-2004 in 23 cases-15.9% (5.5% out of the total investigated cases), the knife identification was based on the skin wound characteristics and dynamic traces in the rib cartilage tissue. In our opinion, the dynamic traces in the rib cartilage tissue investigations supplement the identification field and are valuable in the tool identification. In 11 (2.6% out of the total investigated cases) cases knives were identified only by the skin wounds morphologic characteristics, the ribs being not injured or dynamic traces being not suitable for the tool identification.     

Gunshot residue testing in suicides: Part I: Analysis by scanning electron microscopy with energy-dispersive X-ray

Several different methods can be employed to test for gunshot residue (GSR) on a deceased person's hands, including scanning electron microscopy with energy-dispersive x-ray spectroscopy (SEM-EDX) and inductively coupled plasma-atomic emission spectrometry (ICP-AES). Each of these techniques has been extensively studied, especially on living individuals. The current studies (Part I and Part II) were designed to compare the use and utility of the different GSR testing techniques in a medical examiner setting. In Part I, the hands of deceased persons who died from undisputed suicidal handgun wounds were tested for GSR by SEM-EDX over a 4-year period. A total of 116 cases were studied and analyzed for caliber of weapon, proximity of wound, and results of GSR testing, including spatial deposition upon the hands. It was found that in only 50% of cases with a known self-inflicted gunshot wound was SEM-EDX positive for at least 1 specific particle for GSR. In 18% of the cases there was a discernible pattern (spatial distribution) of the particles on the hand such that the manner in which the weapon was held could be determined. Since only 50% of cases where the person is known to have fired a weapon immediately prior to death were positive for GSR by SEM-EDX, this test should not be relied upon to determine whether a deceased individual has discharged a firearm. Furthermore, in only 18% of cases was a discernible pattern present indicating how the firearm was held. The low sensitivity, along with the low percentage of cases with a discernible pattern, limits the usefulness of GSR test results by SEM-EDX in differentiating self-inflicted from non-self-inflicted wounds.     

Unusual shotgun injury. Gas blowout of anterior head region

During a 6-month period, we encountered two examples of tight contact wounds of the temple region which were associated with ovoid, fairly regular, perforating wounds of the skull and overlying skin. These wounds were located between the eyes with the upper border near the glabella and the lower border near the level of the lower eyelids. There was no evidence that these wounds were entry wounds and in both cases the projectiles were still within the cranial cavity. Therefore, they were interpreted as gas blowout wounds. No similar cases have been found in the literature. Law enforcement personnel and pathologists should be aware of this rather rare blowout type of shotgun injury since it may be subject to various misinterpretations, including that of an entry wound.     

Localization and quantification of the nonspecific esterase in injured skin for timing of wounds.

Histochemical quantification of the nonspecific esterase (NSE) in injured skin was performed using histochemical demonstration of the enzyme and a microspectrophotometric scanning technique on specimens taken from 32 Hartley guinea-pigs and 8 cases of human skin wounds. In all antemortem incisions and lacerations, including those made at the agonal stage, NSE activity could be observed in the dermal tissue of the wound edge. The enzyme activity increases with the antemortem duration of the injuries. Both total content and mean concentration of NSE in the wound edge between antemortem and postmortem wound groups differ significantly (less than 0.01). Multiple range test shows that significant differences (P less than 0.05 or P less than 0.01) of total content of NSE in the wound edge also exist in 0-5 min, 15-30 min, 1-h, 2-h and 4-h antemortem incised wound groups and in 0-min, 5-min, 15-30 min, 1-h and 4-h antemortem laceration groups. The positive NSE reactions in 8 cases of human skin wounds were similar. The study indicates that histochemical quantification of NSE in injured skin is very useful in timing wounds and is exactly applicable in medicolegal practice. According to the different influences of inhibitors on enzymes, it was inferred that the enzyme activity in wound edges was due to B-esterase.     

Localization and quantification of histamine in injured skin as parameters for the timing of wounds.

Localization and estimation of the histamine (HA) content in skin wound edges in 86 Sprague-Dawley rats and three cases of human injuries were carried out by a microfluorimetric method specific for this amine which forms a complex with o-phthalaldehyde (OPT). Distribution and density of the mast cells in the same areas were observed at the same time by toluidine blue stain. In all skin specimens with antemortem wounds, both the epidermis and upper dermis exhibit extracellular yellowish fluorescence of the HA-OPT complex. The fluorescent zone spreads in the wound edges with the lapse of time in vital injuries. The HA content increases gradually up to 30 min and then the yellow histamine fluorescence in areas 0-200 microns from the wound edge decreases. None of these features can be observed in normal skin and postmortem-injured skin. Mast cell degranulation can be demonstrated in all antemortem-injured skin. No statistical relationship exists between the number of mast cells and the HA-OPT fluorescence in either ante- or postmortem-injured groups. This study indicates that skin HA microfluorimetry by the OPT method is of practical value for distinguishing ante- from the postmortem wounds and for timing antemortem wounds.     

Neonatal Limb Amputation—An Unusual Form of Postmortem Canine Predation

Cases of postmortem canine predation often involve elderly recluses and their dogs. The face, head, and genitalia are targeted. Two unusual cases of postmortem canine predation of abandoned newborns are described to demonstrate an unusual alternative pattern of mutilation related to the small size of the decedents, marked decomposition, and canine scavenging behavior. Both bodies were abandoned/concealed soon after birth and were subsequently disturbed by dogs. Both were markedly decomposed with absent arms. Other injuries included skin and soft tissue defects of the torsos, with loss of distal portions of the right foot and the left lower leg in one case. No interstitial hemorrhage was observed in any of the exposed soft tissue wounds. There were no significant head or neck injuries. These cases show that patterns of postmortem canine predation will vary depending on the age, physical characteristics, degree of decomposition, and location of decedents.     

Tentative injuries to exposed skin in a homicide case.

A 28-year-old man stabbed both his wife and his 3-year-old son to death, before unsuccessfully attempting to commit suicide. The incident occurred against a background of marital conflict. The child's body exhibited six tentative wounds to the skin in the area of the heart, with no corresponding defects in the overlying clothing, a pattern normally seen only in suicide. Their presence can be explained by the fact that this can be considered an extended suicide, the father's motivation for the killing being comparable to that for true suicide. However, wounds of this nature can be produced in such cases only if the victim is severely limited in his ability to defend himself, here due to the superior physical strength of the father.     

Tool mark striations in pig skin produced by stabs from a serrated blade

Stab wounds produced by serrated blades are generally indistinguishable from stab wounds produced by non-serrated blades, except when visible tool mark striations are left on severed cartilage. Using a pig-skin experimental model, we explored the possibility that similar striations may be left in skin. Stabs into pig skin were made using a straight spine coarsely serrated blade (121), a drop point finely serrated blade (20), a clip point irregular coarsely serrated blade (20), a drop point coarsely serrated blade (15), and as controls 2 non-serrated blades (40). Tool mark striations could be seen on the skin wall of the stab canal in all stabs made using serrated blades but in none with non-serrated blades.The striation pattern, reflecting the class characteristics of the serrated blade, was the same as that described in cartilage but less well defined. Fixation of the specimen with Carnoy's solution best preserved visible striations, and fixation with formaldehyde after staining with 5% Neutral Red was also satisfactory. Casting with vinyl polysiloxane dental impression material greatly facilitated photo-documentation. Applying the technique to homicidal stabbings may help identify stab wounds produced with serrated blades.     

Fetal gunshot wound characteristics

Firearm injury in pregnant women is reported in the literature; however, no articles to date address the forensic analysis of the wounds sustained by the fetus. This is a report of a 40 weeks gestational age fetus who died following multiple perforating gunshot wounds, while his mother survived. The fetal wounds were atypical, consisting of irregular perforations with radiating linear lacerations and adjacent abrasions. The unusual wound pattern may have been due to the presence of interposed targets, the shoring of the fetus against itself and the uterine corpus, and the intrinsic character of fetal skin.     

损伤皮肤中组胺荧光显微定位定量与损伤时间推断的实验研究

本文应用显微荧光分光光度计法研究大白鼠皮肤创缘组织中组胺的分布和含量,并用甲苯胺蓝法观察创缘肥大细胞形态和数量的变化。结果发现,创缘真皮乳头层出现扩散的细胞外黄色荧光和肥大细胞脱颗粒现象为生前伤的重要特点;组胺荧光分布范围及增多的程度与损伤时间密切相关。从而为损伤时间推断提供了一种新的方法。     

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).     

Study of elastic fiber changes of human skin in distinction between antemortem and postmortem wounds

Elastic fiber changes of volunteers' antemortem and postmortem skin wounds of various time were observed in order to find possible differences between them. These sections of the wounds were stained by Hart's modification of Weigert's elastic tissue stain.. However, this study showed that there were no differences in the nature and distribution of the elastic fibers in the dermis of volunteers' antemortem and postmortem human skin wounds. Therefore, this suggests that the appearances of the elastic fibers in the dermis should not be as a means of differentiating antemortem skin wounds from postmortem wounds in forensic identification.     

Pathologic features of fatal shark attacks

To examine the pattern of injuries in cases of fatal shark attack in South Australian waters, the authors examined the files of their institution for all cases of shark attack in which full autopsies had been performed over the past 25 years, from 1974 to 1998. Of the seven deaths attributed to shark attack during this period, full autopsies were performed in only two cases. In the remaining five cases, bodies either had not been found or were incomplete. Case 1 was a 27-year-old male surfer who had been attacked by a shark. At autopsy, the main areas of injury involved the right thigh, which displayed characteristic teeth marks, extensive soft tissue damage, and incision of the femoral artery. There were also incised wounds of the right wrist. Bony injury was minimal, and no shark teeth were recovered. Case 2 was a 26-year-old male diver who had been attacked by a shark. At autopsy, the main areas of injury involved the left thigh and lower leg, which displayed characteristic teeth marks, extensive soft tissue damage, and incised wounds of the femoral artery and vein. There was also soft tissue trauma to the left wrist, with transection of the radial artery and vein. Bony injury was minimal, and no shark teeth were recovered. In both cases, death resulted from exsanguination following a similar pattern of soft tissue and vascular damage to a leg and arm. This type of injury is in keeping with predator attack from underneath or behind, with the most severe injuries involving one leg. Less severe injuries to the arms may have occurred during the ensuing struggle. Reconstruction of the damaged limb in case 2 by sewing together skin, soft tissue, and muscle bundles not only revealed that no soft tissue was missing but also gave a clearer picture of the pattern of teeth marks, direction of the attack, and species of predator.     

Soft tissue radiography in determining contact and near-contact gunshot wounds.

Contact and near-contact gunshot wounds ordinarily show distinctive gunpowder patterns, muzzle imprints, or tearing of the skin. Microscopic and chemical examination have been used to estimate firing distances. A new method that utilizes soft tissue radiography is described. Nonjacketed lead bullets deposit a pattern of fragments and residues in tissue circumscribing contact and close gunshot wounds. Various patterns are presented to contrast the appearance of contact from distant gunshot wounds using various firearms and different types of bullets. This procedure may be used as an adjunct in the determination of contact and close gunshot wounds.     

Expression of adhesion molecules in skin wounds: diagnostic value in legal medicine

The adhesion molecules identified in recent years can help improve the diagnosis of the wound age, especially of injuries with a short survival time. This is also indicative of the vitality of the wounds. The material investigated in the study originated from 465 skin wounds. The samples were taken from human autopsy material, during the surgical treatment of wounds (excision) of patients and from experimental incised wounds of mice. To judge the age of skin wounds the endothelial adhesion molecules were detected in paraffin sections after autoclaving and using the ABC technique. Human skin wounds: strong positive staining was observed of ICAM-1 1.5 h at the earliest and 3.5 days at the latest, for the P-selectin 3 min at the earliest and 7 h at the latest, for the E-selectin 1 h at the earliest and 17 days at the latest and for VCAM-1 3 h at the earliest and 3.5 days at the latest after the time of injury. The L-selectin was expressed constitutively. Mice skin wounds: strong positive immunohistochemical reactions were found as a rule earlier than in human skin wounds. The detection of an increased expression of ICAM-1, VCAM-1 and P- and E-selectins can improve the wound age assessment in injuries with short survival times.     

Simulation of an attack by self-mutilating cuts and stab wounds

Self-inflicted cut or stab wounds may be used by the injured to make credible a feigned assault. In such cases the alleged traces of the crime are found on the body and the clothing of the informant. Occasionally the very pattern of the injuries points to self-infliction. For example the following findings may be indicative of self-infliction: a greater number of very superficial wounds, wounds parallel or grouped, mostly located on the left side of the body (in right-handers) or symmetry in arrangement, intact clothing or lack of correspondence between wounds and damage of clothing, absence of typical defence and protection injuries. In the light of 4 cases observed from the material at hand, special features of the lesion appearance are shown and possible motives for the deed discussed.     

Pattern of intersecting fractures and direction of fire

In gunshot wounds of the skull, the pattern of intersecting fractures may be used to verify the direction of fire. It may be the only indicator of direction, if overlying skin is destroyed or inconclusive and if bevelling is absent in gunshot defects of thin temporal bone.     

The detection of metallic residues in skin stab wounds by means of SEM-EDS: A pilot study

The morphological analysis of stab wounds may often not be accurate enough to link it with the type of wounding weapon, but a further evaluation may be performed with the search for metallic residues left during the contact between the instrument and the skin. In this study, Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS) was applied to the study of cadaveric stab wounds performed with kitchen knives composed of iron, chromium and nickel, in order to verify the presence of metallic residues on the wound's edge. Two groups of 10 corpses were selected: group A, including victims of stab wounds and a control group B (died of natural causes). Samplings were performed on the lesions and in intact areas of group A, whereas in group B sampling were performed in non-exposed intact skin. Samples were then analysed with optical microscopy and SEM-EDS. In group A, optical microscopic analysis showed the presence of vital haemorrhagic infiltration, while SEM-EDS showed evidence of microscopic metal traces, isolated or clustered, consisting of iron, chromium and nickel. Moreover, in two cases organic residues of calcium and phosphate were detected, as a probable sign of bone lesion. Control samples (group A in intact areas and group B), were negative for the search of exogenous material to optical microscopy and SEM-EDS. The results show the utility and possible application of the SEM-EDS in theidentification of metallic residues from sharp weapons on the skin.