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This work deals with the examination of tool marks in human cartilage. We compared the effectiveness of several cleaning methods on cut marks in porcine cartilage. The method cleaning by multiple casts achieved the significantly highest scores (P = 0.02). Furthermore, we examined the grain-like elevations (dots) located on casts of cut cartilage. The results of this study suggest that the casting material forms these dots when penetrating cartilage cavities, which are areas where the strong collagen fibres leave space for the chondrocytes. We performed fixation experiments to avoid this, without success. In addition, 31 casting materials were compared regarding contrast under light-microscope and 3D tool marks scanner. Under the light-microscope, brown materials achieved significantly higher values than grey (P = 0.02) or black (P = 0.00) whereas under the 3D scanner, black materials reached higher contrast values than grey (P = 0.04) or brown (P = 0.047). To compare the accuracy and reproducibility of 6 test materials for cartilage, we used 10 knives to create cut marks that were subsequently scanned. During the alignment of the individual signals of each mark, the cross-correlation coefficients (X max ) and lags (L Xmax ) were calculated. The signals of the marks in agarose were aligned with significantly fewer lags and achieved significantly higher cross-correlation coefficients compared to all tested materials (both P = 0.00). Moreover, we determined the cross-correlation coefficients (X C ) for known-matches (KM) per material. Agarose achieved significantly higher values than AccuTrans®, Clear Ballistics™, and gelatine (all P = 0.00). The results of this work provide valuable insights for the forensic investigation of marks in human costal cartilage., (© 2021. The Author(s).)

This paper describes the variety of information that a tool mark analysis on human tissue can provide based on a case of multiple sharp violence. The perpetrator attacked the victim with a sharp-edged weapon against the head, leaving several deep wounds on the back of the skull bone. Three of those marks on the skull bone could be used for a forensic tool mark examination. Silicone casts of the marks were compared by light microscopy with casts of test marks of Japanese katana swords found at the crime scene. One of the swords could be identified as the one responsible for the marks. In addition, the marks and the test marks were scanned in 3D and examined in a visual on-screen comparison confirming the results from the light microscopic examination. Furthermore, a mathematical approach in which the signatures of the marks from the skull bone and the test marks from the sword were compared by cross correlation confirms those findings. In addition, the aforementioned results were used to determine the orientation of the sword in relation to the cranial bone at the time of the respective impact.

Identifying tool mark and involved weapon in sharp force trauma is essential to understanding the circumstances of death. But accuracy and reliability of such expert testimony remains unknown, and validation studies are rare in forensic literature. That is why, we conducted an experiment in order to determine error rates and predictive values on identifying the right implement through different types of knife-inflicted trauma. Human bone cut marks were analysed through epifluorescence microscopy. The samples were examined through a randomised, blinded, controlled study by three researchers with varying degrees of experience with direct and indirect observation of cut marks (photography). Our results showed that identifying the weapon involved is possible thanks to numerous criteria analysis. Correct classification rates were high and misclassifications rare. Asymmetric blades obtained better results than symmetric blades. Predictive values were also calculated, and the negative one reached very high levels, near 100% with regard to all the implements. Positive predictive values were more variable. But even if individual diagnoses remain in doubt, triage can be done and tools not implicated in injury can be eliminated with certainty. Moreover, our work clearly highlighted the importance of experience in such activities. A high level of experience is fundamental to obtain the best values, especially in such a context where evidence reliability is extremely important for forensic admissibility testimony in the court.

Stabbing with a kitchen knife is a common method of homicide in Europe. Serrated knives may leave tool markings (striations) in tissues. Documentation of striations is necessary for their use as forensic evidence. Traditional methods (physical casting and photography) have significant limitations, and micro-computed tomography (micro-CT) has been trialled in cartilage to "virtually cast" wounds. Previous research has shown the proportion of striations in cartilage falls following decomposition. This project has investigated the effects of taphonomic alteration and documentation methods of striations in porcine skin. Fresh, decomposed, mummified, burnt and waterlogged stab wounds in a porcine analogue were excised and imaged using photography, stereo-optical microscopy and micro-CT. The proportion of striations in each taphonomic group was determined from the images by independent analysts. Striations were observed more frequently in serrated blade wounds, although they were also identified in non-serrated blade wounds. The proportion of wounds showing striations declined following decomposition. An inversely proportional linear correlation between advancing decomposition and proportion of striations existed. Dehydration (mummification and burning) rendered serrated and non-serrated blade wounds indistinguishable. Water composition affected the preservation of striations. Identification of striations gradually declined after decomposition in tap water, but persisted to a point when left in brackish water. All three techniques imaged striations; however, the optimum technique was stereo-optical microscopy due to practical advantages and specific limitations affecting photography and micro-CT. This study demonstrates the effects of taphonomic alteration on striations and suggests stereo-optical microscopy is the optimum method for their documentation.

This paper describes a new approach to determine characteristics of the implement used to inflict trauma which involves the histological analysis of exogenous particles. Based on Locard's principle "every contact leaves a trace," we decided to assess whether histological examination of bone and soft tissue around a penetrating injury (sharp force trauma) could provide evidence of the offending implement. Case reports and experimental studies have demonstrated the potential of cut mark features in bone to identify the causative implement and potentially assist in identifying the perpetrator. Scanning electron microscopy in combination with energy-dispersive X-ray spectrometry (SEM/EDS) have previously been reported to identify exogenous particles from various implements. In medical research, histological techniques are used to study the impact of foreign particles in tissues originating from implants. However, the routine use of histology in forensic medicine focuses on understanding type and timing of injuries. Based on three forensic cases, the results presented in this paper demonstrate that histology offers a cost-efficient and reliable means to detect foreign particles related to offending implement and/or to the environment where the victim was located. The interpretation of histological results was performed in conjunction with the macroscopic autopsy findings and anthropological analysis of bone samples.

Characteristics of sharp bone trauma can be extremely useful to determine the origin of cut marks and to provide information regarding the context of death. Using human ribs and clavicle bones, this study analyzes the characteristics of bone kerfs made by different bladed implements, thanks to epifluorescence macroscopy. This technique, which is a nondestructive tool that uses autofluorescence of bones, documents bone damage precisely with high resolution. Both qualitative and quantitative criteria are analyzed. Our results identify unique class characteristics on bone lesions, allowing modeling kerf depending on the weapon, regardless of the type of bone that is wounded. Moreover, we demonstrate for the first time microscopic criteria of directionality, using fluorescence excitation. Orientation of cracks, flakes, and lateral pushing back especially helps in determining the tip and the end of the lesion, leading to the position of the aggressor. Kerf wall characteristics and striation location are also very useful. Epifluorescence macroscopy could be a new tool of choice in anthropology through cut mark analysis in establishing how the blade was used and providing details about the blow.

A block of an injury instrument will be left in wounds sometimes, and the suspect instrument can be discriminated by comparison with the block that was left through elemental analysis. In this study, three brands (Shibazi, Zhangxiaoquan, Qiaoxifu) of kitchen knives with forged, chop, and slice application series were analyzed by inductively coupled plasma atomic emission spectroscopy (ICP-AES) and Infrared Absorption to investigate the type, number of elements and the reference range used for comparing. The results show that when regarding one or more element as the discriminative threshold, together with 5% relative standard deviation (RSD) as the reference range, all the samples could be distinguished among different series. Furthermore, within the same series, the discriminative capability could reach up to 88.57% for all samples. In addition, elements with high content, such as Cr, Mn, and C, were useful to discriminate among different series, and trace elements, such as Ni, Si, and Cu, were useful within the same series. However, in practice, it is necessary to evaluate the accuracy of the method by Standard Reference Material (SRM) before an examination is performed.

This study aims at verifying the potential of a recent radiological technology, cone beam CT (CBCT), for the reproduction of digital 3D models which may allow the user to verify the inner morphology of sharp force wounds within the bone tissue. Several sharp force wounds were produced by both single and double cutting edge weapons on cancellous and cortical bone, and then acquired by cone beam CT scan. The lesions were analysed by different software (a DICOM file viewer and reverse engineering software). Results verified the limited performances of such technology for lesions made on cortical bone, whereas on cancellous bone reliable models were obtained, and the precise morphology within the bone tissues was visible. On the basis of such results, a method for differential diagnosis between cutmarks by sharp tools with a single and two cutting edges can be proposed. On the other hand, the metrical computerised analysis of lesions highlights a clear increase of error range for measurements under 3 mm. Metric data taken by different operators shows a strong dispersion (% relative standard deviation). This pilot study shows that the use of CBCT technology can improve the investigation of morphological stab wounds on cancellous bone. Conversely metric analysis of the lesions as well as morphological analysis of wound dimension under 3 mm do not seem to be reliable.

The timing of skin wounds is one of the most challenging problems in forensic pathology. In the first minutes or hours after infliction, histological examination fails to determine whether a wound was sustained before or after death. The aim of this study was to evaluate the use of three immunohistochemical markers (FVIIIra, CD15, and tryptase) for the interpretation of the timing of cutaneous stab wounds. We evaluated these markers in intravital wounds from autopsy cases (n = 12) and surgical specimens (n = 58). As controls, we used normal skin samples from autopsies (n = 8) and an original ex vivo surgical human model of recent postmortem wounds (n = 24). We found overexpression of FVIIIra in 100 % of vital wounds, but also in 53 % of the controls. The number of CD15-positive cells was higher in wound margins than in internal controls (p < 0.0001) and was significantly correlated with the time interval between incision and devascularization (p = 0.0005; minimal time for positivity, 9 min). Using the anti-tryptase antibody, we found that the mast cell degranulation rate was higher in wound margins (p < 0.0001) and correlated with the time interval (minimal time, 1 min). The sensitivity and specificity for the diagnosis of vitality were respectively 100 and 47 % for FVIIIra, 47 and 100 % for CD15, and 60 and 100 % for tryptase. The inter-observer agreement coefficients were 0.68 for FVIIIra, 0.90 for CD15, and 0.46 for tryptase. Finally, we demonstrated that these markers were not reliable in putrefied or desiccated specimens. In conclusion, CD15 and tryptase, but not FVIIIra, may be useful markers for differentiating recent antemortem from postmortem injuries.

This paper presents an experiment with a knife seized as material evidence in a homicide case. The reason for the experiment was the necessity to determine whether the injuries of the deceased could have been inflicted with this instrument since in the course of the investigation doubt arose as to the origin of linear, parallel scratches around one of the wounds and on the abdominal integuments suggesting a serrated blade. The knife found near the crime scene had a smooth blade and small serrations only on the borderline between its blade and hilt. However, the performed experiment showed that if the knife is directed towards the integuments of the body in a special way, its serrations, even though not located on the blade itself, may leave such striated marks on the body, as those found during the autopsy, suggesting their origin from a serrated blade.

Although evidence of sharp-force trauma on the human body, particularly the skeleton, can be extremely useful in providing information regarding the manner and context of death, there is still a lack of necessary detail available to the investigator. Using ribs, radii, scapulae, vertebrae and carpal bones, this study demonstrated that distinctions could be made between the stab marks left by serrated blades and those of non-serrated blades. Low power and scanning electron microscopy were used to record distinctive 'T'-shaped stab marks from non-serrated blades and 'Y'-shaped stab marks from serrated blades. In addition, elemental evidence of the presence of the blade in the stab-mark kerf was recoverable even when no metal fragment was visible.

Stabbing is the most common method for violent death in the UK. As part of their investigation, forensic pathologists are commonly asked to estimate or quantify the degree of force required to create a wound. The force required to penetrate the skin and body by a knife is a complex function of the sharpness of the knife, the area of the body and alignment with cleavage lines of the skin, the angle of attack and the relative movement of the person stabbing relative to the victim being stabbed. This makes it difficult for the forensic pathologist to give an objective answer to the question; hence, subjective estimations are often used. One area where some degree of quantification is more tractable is in assessing how sharp an implement (particularly a knife) is. This paper presents results of a systematic study of how the different aspects of knife geometry influence sharpness and presents a simple test for assessing knife sharpness using drop testing. The results show that the radius of the blunt edge at the tip is important for controlling the penetration ability of a kitchen knife. Using high-speed video, it also gives insight into the mechanism of knife penetration into the skin. The results of the study will aid pathologists in giving a more informed answer to the question of the degree of force used in stabbing.

A 31-year-old woman was found dead by her daughter, lying in the living room which showed a large pool of blood, secondary droplets and stains from arterial blood spatter, dropping and contact. This bloody scene and two puncture wounds at the anterior aspect of the neck, one of them transecting the left common carotid artery leading to exsanguination, arose suspicion of homicide. However, the wound morphology including notches and a parallel skin incision as well as microradiography demonstrated that the two puncture wounds had been produced by glass. At the scene, a broken wine glass with two dagger-like tips had been standing on a table in front of a sofa where the woman had been sitting, and she most likely sustained the injury when she suddenly moved her head downwards, thus moving into the protruding tips. This self-inflicted accident demonstrates that inspection of the scene and synthesis of autopsy and scene findings can be crucial for a successful medico-legal reconstruction. The mechanism of producing the accidental injury is very extraordinary, in that the woman actively moved into a shattered wine glass instead of falling into an intact architectural glass surface.

The assessment of individual wounds at autopsy may be complicated by the superimposition of a number of injuries or damage to tissues that occurred after death, either of which has the potential to distort the morphology of the initial injury. Additional factors that may change the shape of wounds are (1) the relationship of the wound to the so-called skin cleavage lines (Langer's lines) and (2) tension placed on the skin. Three autopsy cases are reported to demonstrate once more how wound morphology may be altered by such factors. In case 1, rectangular stab wounds to the base of the neck in a 53-year-old man, which suggested that a square or rectangular tool may have caused the injuries, were altered to more typical knife stab wounds once skin tension had been released at autopsy. The uppermost wounds, however, continued to gape due to the effects of skin cleavage lines. In case 2, slit-like wounds resembling stab wounds in the neck of a 54-year-old woman found in a river were shown to be circular once skin tension had been released. In case 3, the effects of either cleavage lines or skin tension could be demonstrated on excised wounds from a 43-year-old man whose body had also been found in a river; tensile forces easily changed circular into slit-like wounds. Tension and/or skin cleavage lines may transform round skin defects into slit-like wounds resembling knife stab wounds, round out genuine stab wounds and artefactually lengthen stab wounds. These factors must be taken into consideration carefully when wounds are assessed at the death scene prior to autopsy.

A case of a 25-year-old male with a deep knife stab injury in the back is reported. The stab wound penetrated the left thorax and the left lung was injured, a thoracotomy was performed and the patient survived. The injured man could not remember what had happened, his bag was missing and the incident was therefore considered to be due to a robbery. Further results of the police investigations and the forensic pathology inspection revealed an extremely unusual accident constellation.

In a knife attack the perpetrator can unintentionally injure his own hand, if the knife does not have an adequate handguard and the tip of the blade hits a solid, mostly bony structure while being violently thrust into the victim's body. The injuries occurring under these conditions are localized on the flexor side of the knife-holding hand and may include the index, middle, ring and little fingers. They are seen particularly often on the little finger at the level of the proximal phalanx and in the skin fold of the proximal interphalangeal joint. The majority of these cuts run transversely to the longitudinal axis of the fingers and can show a step-like arrangement with different distances to the metacarpophalangeal joints, often from ulnar-proximal to radial-distal. In the six cases presented the injuries were most pronounced on the ulnar side of the hand. When the flexor tendons of the fingers are also severed and the tendon stumps are strongly retracted this indicates that the fist was firmly closed at the time of the injury.

A man committed suicide in his bathroom using a small pocket knife. At the autopsy a total of 92 stab wounds on the forehead, in both temples, the anterior aspect of the neck, the back of the neck, the chest and the sides of the trunk were found. In addition, repeated stabbing had caused a large soft tissue defect on the forehead. The frontal bone showed 3 perforations but no brain injury was present and two ribs were severed in the bony part, one of which carried a star-like pattern from repeated stabbing. No major vessels were injured and the cause of death was exsanguination after a considerable survival time. The large number of stab wounds, the perforation of bone and some injury sites, especially the head and back of the neck, are extraordinary findings in suicides which were probably favoured by insufficient anatomical knowledge and the use of a short-bladed knife. A psychiatric history could not be verified.

A man suffered a fatal injury from a self-inflicted accident while handling a special type of knife. A spring in the shaft of the knife accelerated the blade, which perforated the orbital cavity and the frontal lobe at the right side. Death was due to central disregulation. The initial velocity of the blade was measured to be 15 m/s. In a total of 20 experimental shots to a fresh pig cadaver, the blade always penetrated the skin and 5-10 cm of soft tissue as long as the distance did not exceed 1 m. Thin layers of bone were also perforated. The free flight of the blade did not remain stable if the distance was more than 1 m, which resulted in superficial wounds only. So this unusual construction resembling a knife can be considered an effective combat weapon for close range fighting instead of a tool.

A skeletonised body was found in a Danish forest. The examination of the bones revealed several incision on the skeleton, one located on the cervical column, two on the sternum, one perforating incision to the right iliac crest, and several superficial ones to the ribs and the right tibia. The skeletonized body was thought to be that of a young man in the twenties with a height of 170 cm. It was estimated that the body has been lying at the spot for at least 1 or 2 y and had been murdered by several stab wounds to the chest and abdomen. Police enquiries subsequently revealed that the deceased was a 23-year-old male with a height of 171 cm. A man confessed to having murdered the victim 1 1/2 years earlier with several stab wounds to the face/neck, chest, abdominal wall and thigh.

A case of suicide by harakiri is described. The position of the subject, the absence of the shirt and the abdominal L-shape cut agreed well with the formal procedure of harakiri. The characteristics of the stab wounds present on the right-hand side of the neck confirmed the assumption of self-infliction and excluded, from a legal point of view, murder by consent.

A total of 117 vital skin wounds (post infliction intervals between a few seconds and 7 months), 20 postmortem wounds and skin specimens with beginning or advanced signs of putrefaction were investigated. Different markers for macrophage maturation (27 E 10, RM 3/1, 25 F 9, G 16/1) were analyzed by immunohistochemistry. The early stage inflammation marker 27 E 10 stained macrophages, but also monocytes and neutrophilic granulocytes localized in blood vessels or bleeding induced postmortem and therefore provided no further information for a forensic wound age estimation in comparison to the routine histological detection of macrophages. The antigens recognized by the RM 3/1- (intermediate stage inflammation marker) and 25 F 9-antibodies (late stage inflammation marker) were expressed exclusively by histiocytes and inflammatory cells that had migrated from the blood vessels as part of the acute inflammatory response associated with an intravital reaction. The morphometrical analysis revealed positive results (defined as at least a two-fold increase in number in 2 or more microscope fields when compared to the maximum value of histiocytes found in uninjured skin) for the RM 3/1- or 25 F 9-antibody earliest in wounds aged 7 or 11 days, respectively. Similarly to the 25 F 9-antibody, the chronic stage inflammation marker (G 16/1) reacted with a macrophage subpopulation first detectable 12 days after wounding but showed positive results in a comparably reduced percentage of cases. On the other hand, this marker did not stain a relevant number of resident macrophages thus facilitating the evaluation of the specimens.(ABSTRACT TRUNCATED AT 250 WORDS)

The distribution of the proteinase inhibitors alpha-1-antichymotrypsin (alpha 1-act), alpha-2-macroglobulin (alpha-2-m) and lysozyme was analysed immunohistochemically in 27 intravitally acquired wounds, 3 postmortem skin lacerations and 9 specimens of undamaged skin. Intravitally acquired wounds demonstrated distinct positive reactions for all antibodies examined (alpha-1-act 66.6%; alpha-2-m 51.9%; lysozyme 25.9%). However the undamaged skin margins opposite the wound margins also gave positive reactions (alpha-1-act 51.8%; alpha-2-m 37.0%; lysozyme 25.9%). Nearly half of the control cases (specimens of undamaged skin) exhibited weak positive reactions for all 3 antibodies. These could be easily distinguished from the strong positive reactions observed in intravitally acquired wounds. False positive reactions were observed due to contamination resulting from contact with serum components, in cases of advanced autolysis of specimens, and as a result of fixation and drying artefacts. Even though immunohistochemical studies of alpha-1-act, alpha-2-m and lysozyme give some indications concerning wound vitality, they cannot be considered as proof because irrefutable differentiation of true positive and false positive reactions is not possible in all cases.

A total of 56 surgically treated human skin wounds with a wound age between 8h and 7 months were investigated. Tenascin was visualized by immunohistochemistry and appeared first in the wound area pericellularly around fibroblastic cells approximately 2 days after wounding. A network-like interstitial positive staining pattern was first detectable in 3-day-old skin wounds. In all wounds with an age of 5 days or more, intensive reactivity for tenascin could be observed in the lesional area (dermal-epidermal junction, wound edge, areas of bleeding). In wounds with an age of more than approximately 1.5 months no positive staining occurred in the scar tissue. In conclusion, for forensic purposes, positive staining for tenascin restricted to the pericellular area of fibroblastic cells indicates a wound age of at least 2 days. Network-like structures appear after approximately 3 days or more. Since tenascin seems to be regularly detectable in skin wounds older than 5 days, the lack of a positive reaction in a sufficient number of specimens indicates a wound age of less than 5 days. The lack of a positive reaction in the granulation tissue of wounds with advanced wound age indicates a survival time of more than about 1.5 months, but a positive staining in older wounds cannot be excluded.

A total of 39 vital human skin wounds (20 cases with short survival times ranging from a few seconds to approximately 30 min and 19 cases with wound ages between 50 min and 13 days) were investigated. Alpha 1-antichymotrypsin (A1-ACT) was visualized by immunohistochemistry. Additionally, fibronectin was localized in 13 of these wounds (8 cases with short and 5 cases with longer survival times). Furthermore, 13 postmortem lesions (stab wounds) were removed from corpses approximately 4 h after infliction and analyzed for A1-ACT and fibronectin. The "vital" reaction previously described for A1-ACT in form of a band-shaped staining pattern at the wound edges was observed in both vital wounds and in most postmortem lesions. A similar reaction was also obtained for fibronectin in wounds inflicted after death, but could be unambiguously distinguished from vital fibronectin staining by morphological criteria. Therefore, it seems questionable that the vitality of skin wounds can be determined by the immunohistochemical detection of A1-ACT and probably other proteinase inhibitors. The meaning of the localization of fibronectin for the determination of the vitality of human skin wounds with a survival time of at least a few minutes could be confirmed.

Collagen type III and V were visualized immunohistochemically in 79 surgically treated human skin wounds with a wound age between 8 h and 2.5 months. Network-like structures positively staining for collagen type III and associated with fibroblastic cells in the wound area were first detectable in a 2.5-day-old skin lesion and occurred regularly in wounds more than 5 days old. Collagen type V appeared first in the wound area after about 3 days, slightly later than collagen type III, and was detectable regularly in wounds with a survival time of 6 days or more. The immunohistochemical detection of collagen type III or type V thus indicates a wound age of at least 2-3 days. The lack of a positive reaction in a sufficient number of specimens indicates a wound age of less than 6 days. Even though both collagen types could also be detected in older wounds (wound age 2.5 months), further information for the time-estimation of older skin wounds cannot be given due to the observation that the time period during which reparative processes can be observed depends on the extent of the wound area.