Arterial Perfusion—A Useful Technique for Evaluating Incised Wounds

A 54‐year‐old woman was found deceased with incised wounds of both sides of her neck and both wrists. Postmortem CT scanning revealed air in the heart and in the dural veins in continuity with air in the right jugular vein. Death was due to incised wounds of the wrist and neck with blood loss and air embolism. The manner of death was suicide. At autopsy, perfusion of the thoracic ascending aorta produced a fine stream of water emanating from an incised wound of the right ulnar artery with no significant leakage of water from the wound of the left wrist. There was also leakage from the facial artery branch of the right external carotid artery. Perfusion testing can be used as a screening test prior to formal dissection and also to identify small vessels that may not be obvious on standard examination of an exsanguinated field.     

Microscopic Analysis of Sharp Force Trauma in Bone and Cartilage: A Validation Study,,

Sharp force trauma research lacks agreement on reported error rates for correctly identifying toolmark characteristics on bone and cartilage. This study provides error rates for determining blade class (serrated, partially serrated, nonserrated) and type of edge bevel (left, right, even). Three analysts examined cuts to a wax medium, cartilage, and bone using two types of microscopes. Additionally, the observers examined impressions taken from the wax medium and the cartilage. Overall, a total of 504 observations were performed. Serrated blades were distinguishable from nonserrated blades due to their patterned striations. Some difficulties were encountered in distinguishing serrated and partially serrated blades; however, when these groups were considered together as one classification type (serrated), classification accuracy improved from 79% to 96%. Classification accuracy for edge bevel was 65%. Error rates were similar when comparing direct observation of the cut marks versus indirect observation (impressions). Additionally, the type of microscope used did not affect error rates.     

Forces Required for a Knife to Penetrate a Variety of Clothing Types

In stabbing incidents, it is usual for the victim to be clothed and therefore a knife penetrates both clothes and skin. Clothes (other than leather) have been thought to make little difference to the penetration force. However, there is little quantitative data in the literature. In this study, a range of clothes have been tested, either singly or in layers of, for example, T‐shirt and shirt, to quantify the additional force required when clothes are present. A materials testing system has been used to test the penetration force required to stab through clothes into a foam–silicone rubber skin simulant. The results show that the force required can be significantly different, particularly when layers of clothing are penetrated. A cotton t‐shirt adds c. 8 N to the penetration force, while a T‐shirt and jacket can add an additional 21 N. The results allow a more quantitative assessment of forces required in stabbing.     

Patterns of trauma in conflict victims from Timor Leste

Understanding population-level trauma patterns has implications for the recognition of war crimes and crimes against humanity. Trauma data were abstracted from autopsy and anthropology reports for 105 victims from the 1999 conflict in Timor Leste. A significant number of individuals displayed no evidence of injury. No trauma was found in 25% of the sample, while a further 5% had only minor, nonlethal wounds. Where trauma was evident, sharp force injuries were most common (35%), followed by gunshot (20%) and blunt force (13.33%). Timorese frequencies of trauma differ significantly from percentages found in prior reports of mass killings from Cambodia, Bosnia, Croatia, and Afghanistan but closely resemble reported trauma patterns in Rwanda. Decomposition and percentage of body recovered were shown to have a significant impact on the presence/absence of trauma. Complete, fleshed remains were 10.4 times more likely than skeletal remains to have evidence of major or lethal trauma.     

SEM and Stereomicroscopic Analysis of Cut Marks in Fresh and Burned Bone

This study documents the prevalence of cut mark characteristics in fresh and burned domestic pig ribs. Stab wounds from single edge serrated and smooth‐edged knives were inflicted in the vertebral and sternal regions of each fresh rib. Each rack of ribs was then divided into vertebral and sternal units. Vertebral units were defleshed and their associated cut marks were examined using a stereomicroscope. Sternal units were burned in an outdoor fire pit and examined with the addition of a scanning electron microscope (SEM). Linear cuts, V‐shaped cross‐sections, mounding, hinge fractures, and wastage were all observed on burned ribs. There was an overall decrease in the prevalence of all features (up to a 40% decrease), regardless of knife type, in burned ribs. Striations within cut marks were not observed in either fresh or burned ribs. Oblique faulting and bone lifts could only be observed using the SEM. Mounding and wastage were obliterated during the burning process. Therefore, cut marks in burned bone should ideally be examined for their characteristics utilizing an SEM.     

The Erratic Behavior of Lesions in Burnt Bone

This study analyses depressed fractures (by blunt force trauma) and circular full‐thickness injuries (drill injuries and gunshot wounds) in charred bones. Fifty bovine ribs (total 104 lesions) were divided into three groups. The first group consisted in 20 depressed hammer‐produced fractures; in the second one, 60 round drill‐holes were produced (30 circular, 30 semicircular); in the third group, 12 fleshed and 12 skeletonized ribs were hit by 9‐mm bullets. Each specimen was carbonized in an electric oven up to 800°C. Morphological and metric analyses were performed before and after: morphological features were preserved, but depressed fractures showed an increase in their dimensions (p‐value < 0.05); the drilled holes shrunk (p‐value < 0.01); the charring cycle increased the number of fractures in samples with gunshot wounds differently in fleshed and defleshed ribs. This study showed the complex behavior of charred bone, for what concerns the interpretation of trauma and how caution should be applied.     

Characteristics and Frequency of Chipping Effects in Near‐Contact Gunshot Wounds

The presence of “chipping” or “flaking” around the edges of gunshot entry wounds has been described among the characteristics of gunshot wounds in bone. In this study, the real frequency of such a peculiar feature was investigated. The presence of “chipping” was assessed on 22 gunshot wounds fired at a near‐contact range on bovine ribs with 9‐mm bullets. As controls, five samples were shot with a 3 cm range, and five from 40 cm. In 77% of cases shot at near‐contact range, a detachment of small fragments of the upper layers of bone was detected, mainly with a circumferential disposition, whereas this feature was lacking in control samples. The study demonstrated the frequency of “chipping” and that it may probably be due to a combined ballistic effect of impact of the bullet itself and expansion of gases. It may be thus considered indicative of close‐range shots.     

Macroscopic and microscopic analysis of knife stab wounds on fleshed and clothed ribs

Stab wounds upon bone are analyzed to interpret the weapon used and the physical context in which the attack occurred. The literature demonstrates that most research conducted pertaining to wound patterns has been carried out on defleshed and unclothed bone samples, not adequately replicating actual circumstances. For this research, six half pig torsos (Sus scrofa), fleshed (including muscle, fat, epidermis, and dermis layers) and clothed, were stabbed using three knife types, applying both straight and downward thrusts. Analysis conducted macroscopically and through a scanning electron microscope with an environmental secondary electron detector revealed a general lack of consistency in wound pattern and associated secondary effects. Consequently, it was not possible to establish wound pattern per knife type as suggested in previous research or relate it to stab motion. Advantage of microscopic analysis was evident in recognizing wound traits and observation of trace evidence not visible macroscopically.     

Computational Approach to Identify Different Injuries by Firearms

Complications arise in the analysis of gunshot wounds to the maxillofacial region, when neither the projectile nor the gun is found at the crime scene. We simulated 5‐ and 15‐cm firing distances at a human mandible to investigate the external morphology of entrance wounds based on fire range. The ammunition models, .40‐caliber S&W, .380‐caliber, and 9 × 19‐mm Luger, were constructed with free‐form NURBS surfaces. In a dynamic simulation, projectiles were fired against mandibular body 3D model at 5 and 15 cm. All entrance wounds presented oval aspect. Maximum diameter and von Mises stress values were 16.5 mm and 50.8 MPa, both for .40‐caliber S&W fired at 5 cm. The maximum energy loss was 138.4 J for .40 S&W fired at 15 cm. In conclusion, the mandible was most affected by .40‐caliber S&W and morphological differences were observable in holes caused by different incoming projectile calibers fired at different distances.     

Bullet Caliber and Type Categorization from Gunshot Wounds in Sus Scrofa (Linnaeus) Long Bone

Studies on ballistic trauma to the ribs and thorax, cranium, and long bones demonstrate the potential of obtaining a bullet caliber from an entrance wound. In order to validate prior research on caliber estimation in bone tissue and assess the viability of bullet type determination based on the macroscopic evidence at the entrance wound, thirty fleshed pork (Sus scrofa) shoulders (humeri) were shot with either lead or copper jacketed bullets in one of three calibers; 0.22, 9 mm, or 0.38. Overall, our findings are consistent with previous research indicating that calibers can be grouped into “small” and “large” categories. Bullet type, lead or copper jacket, can be ascertained based on cortical flaking and the analysis of materials deposited around the entry wound. The addition of this evidence holds value in cases where no firearm or ballistic evidence is recovered from a crime scene.     

Fatal and Nonfatal Rip Saw Injuries

This paper deals with a fatal stab wound suffered by a 29-year-old man and nonfatal injuries of 35-year-old and 67-year-old saw operators. Rip saw is a machine that is specially designed for making a rip cut, a cut made parallel to the direction of the wood grain. Rip-saw-related injuries mostly occur when a person is struck by the cutting material, which usually involves splinters of irregular shape and diameter. When the splinter strikes the body diagonally, the injuries may include abrasions, lacerations, and cut wounds; in situations where the victim is struck directly, the most common injuries are oval- or star-shaped stab wounds with a varying width of abrasions around the wounds. Therefore, such injuries may come across as injuries produced by a knife-like instrument, which is an added difficulty in the interpretation of such injuries.     

Patterns of Trauma Induced by Motorboat and Ferry Propellers as Illustrated by Three Known Cases from Rhode Island*

Abstract: Understanding patterns of trauma is important to determining cause and manner of death. A thorough evaluation of taphonomy, trauma, and bone fracture mechanisms is necessary to reconstruct the circumstances of the death. This study examines the skeletal trauma caused by boat propeller strikes in terms of wound characteristics and location based on three cases from Rhode Island. These case studies review the traumatic characteristics caused by propeller injuries and highlight the anatomic regions most likely to sustain skeletal trauma. With this information, investigators may be able to identify propeller trauma even in severely decomposed remains. The discussion of boat propeller trauma also raises issues regarding how forensic anthropologists and forensic pathologists classify trauma (specifically blunt force vs. sharp) and highlights semantic issues arising in trauma classification. The study also discusses why these propeller cases should be classified as blunt trauma rather than sharp or chop/hack trauma. Ultimately, the authors urge consistency and communication between pathologist and forensic anthropologists performing trauma analyses.     

Pseudo-Stab Wounds: Putrefactive Dehiscence of Remote Surgical Incisions Masquerading as Stab Wounds

Abstract:  Artifacts due to decomposition can be mistaken for antemortem injury leading to an incorrect suspicion of foul play. We describe an instance of postmortem wound dehiscence that mimicked antemortem stab wounds. A man with a history of colon cancer and substance abuse was found dead. There were advanced putrefactive changes and multiple defects of the anterior torso that resembled stab wounds. Subsequent investigation revealed that 11 months earlier, he had a laparoscopic-assisted colon resection that involved surgical incisions corresponding in location and size to the above defects. Putrefactive gases may cause bloating of the body. This distension may cause recent and remote healed incisions to dehisce. Correlation of these "defects" at autopsy with the antemortem clinical history is crucial in determining their etiology.     

皮肤切创愈合过程中TLR2、TLR4表达及其法医学意义

目的探讨皮肤切创组织中单核-巨噬细胞TLR2和TLR4阳性表达与损伤时间的相关性,以寻找损伤时间推断的新方法。方法应用免疫组织化学技术研究45例不同损伤时间小鼠皮肤切创组织中TLR2、TLR4的表达情况,同时以3例正常小鼠皮肤组织作对照。结果皮肤切创组织中单核-巨噬细胞TLR2和TLR4阳性表达与损伤时间具有相关性。单核-巨噬细胞TLR2、TLR4阳性细胞比率(单核-巨噬细胞阳性细胞数与中性粒细胞、单核-巨噬细胞及成纤维细胞三种阳性细胞总数之比率)与损伤时间的回归方程分别为y=23.8099 0.9572x-0.0077x2 1.5×10-5x3(R2=0.872);y=25.2256 0.7893x-0.0059x2 1.0×10-5x3(R2=0.879)。结论TLR2、TLR4在小鼠皮肤切创愈合过程中损伤区内单核-巨噬细胞阳性表达比率与损伤时间相关;检测损伤区单核-巨噬细胞TLR2、TLR4的表达可望成为推断损伤时间的新方法。     

A Rare Case of an Intact Bone Plug Associated with a Gunshot Exit Wound

This case study presents an unusual manifestation of gunshot trauma in skeletal tissue from a post‐World War II human rights abuse sample uncovered in Vilnius, Lithuania. After briefly reviewing the typical wound appearance of projectile trauma in the cranium, we discuss the presence of an intact bone plug associated with a gunshot exit wound in an individual from the Tuskulenai Case. While this individual demonstrated typical gunshot entry and exit wounds to the cranium consistent with high‐velocity trauma, the bone plug indicates that the projectile likely lost much of its kinetic energy while traveling through the cranium resulting in a low‐velocity impact at the exit site. This study reviews a similar instance of a bone plug recovered from a bioarcheological sample in Peru and emphasizes the importance of thorough archeological excavations of mass graves.     

Specific Characteristics of Injuries Inflicted by Claw Hammer

Claw hammers have the specific characteristic of having two distinct ends: one a flat head of variable form, the other bifurcated. So the use of this tool as a blunt instrument will cause varying injuries. The authors present two clinical cases of assault with a claw hammer. Examinations revealed two types of wound. A first injury composed of integumentary lacerations and underlying bone injuries in terms of “shape” suggested the use of a blunt instrument. A second injury made up of damage showing two parallel wounds or two wounds located one in the extension of the other suggested the use of an object with a bifurcated end. The combination of both types of injury should alert examiners to the possibility of the use of a claw hammer in causing the injuries in order to help direct investigators in their investigations and in the search for the weapon used.     

Piercing the surface: A mechanical analysis of stabbing with household tools

Estimating the applied power during a stabbing incident, or estimating the minimal force necessary to penetrate the body with a certain weapon is a challenging task in forensic practice. A thorough forensic evaluation of stabbing forces needs objective numerical experimental data. Stabbing tests of 12 different weapons – including knives, a pair of scissors, a fork, screwdrivers, a rasp, a corkscrew, and a utility knife blade – were performed with a Mecmesin MultiTest-dV material tester on pork loin and ballistic gel to estimate the stabbing forces and dynamics. Penetration force (F_p) and maximal force (F_max) were recorded, and the registered force curves were analyzed. F_max was 159.8–212.07 Newton (N), 30.56–30.58 N, 168.9–185.48 N for various knives; 171.39–190.43 N for the pair of scissors, 233.6 N for the fork; 532.65–562.65 N, 370.31–367.19 N and 314.51–432.89 N for various screwdrivers, 44.14–56.62 N for utility knife during pork loin stabbing. The butter knife, corkscrew and rasp were not able to penetrate the pork loin, and the curved fork bent during stabbing. The results prove that weapon characteristics greatly influence the force necessary for penetration. Maximal stabbing force depends mostly on tip sharpness, and the force sharply decreases after penetration occurs, which indicates that edge sharpness is not as important as tip characteristics during stabbing perpendicular to skin surface. The penetration force during stabbing with a pair of scissors is comparable to the penetration force of knives. Stabbing with screwdrivers generally needs larger force than average knives but depends greatly on screwdriver size.     

Hesitation Wounds and Sharp Force Injuries in Forensic Pathology and Psychiatry: Multidisciplinary Review of the Literature and Study of Two Cases

The aim of this paper was to showcase the significant diagnostic value of hesitation wounds in terms of forensic, psychiatric, and medicolegal interest. A number of studies were reviewed to update and summarize the relevant literature on the incidence, distribution, character, and function of hesitation wounds as well as the sociodemographic variables and psychopathology of the inducers. This study also investigates their importance as a forensic criterion in the distinction between suicide and homicide as well as a psychiatric diagnostic tool in suicide prevention. In addition, the paper reports two new cases. Results conclude that there is equal incidence, but different distribution of hesitation wounds between genders. Furthermore, the low dispersion of hesitation wounds contrasts with the high dispersion of defense wounds. The inducers' psychopathology lies principally in Axis I disorders. Finally, there is a comprehensive analysis of non‐suicidal self‐injury and the role of self‐wounding in suicide prevention.