The Accuracy and Applicability of 3D Modeling and Printing Blunt Force Cranial Injuries

The purpose of this study was to determine the factors affecting the accuracy of 3D models and 3D prints of cranial blunt force trauma, to evaluate the applicability and limitations of modeling such injuries. Three types of cranial blunt force lesions were documented (hinge, depressed, and comminuted) using three forms of surface scanning (laser, structured light scanner, and photogrammetry) at two different quality settings (standard and high). 3D printed models of the lesions were produced using two different materials (a gypsum‐like composite powder called VisiJet^® PXL and an acrylic engineered composite plastic called VisiJet^® M3 in crystal colour). The results of these analyzes indicate the prints in this study exhibit some statistically significant differences from the actual bone lesions, but details of the lesions can be reproduced to within 2 mm accuracy.     

Identification of traumatic injury in burned cranial bone: an experimental approach.

Interpreting patterns of injury in victims of fire-related deaths poses challenges for forensic investigators. Determining manner of death (accident, suicide or homicide) using charred remains is compounded by the thermal distortion and fragmentation of soft and skeletal tissues. Heat degrades thin cranial structures and obscures the characteristic signatures of perimortem ballistic, blunt, and sharp force trauma in bone, making differentiation from thermal trauma difficult. This study documents the survivability and features of traumatic injury through all stages of burning for soft tissue reduction and organic degradation of cranial bone. Forty cadaver heads were burned in environments simulating forensic fires. Progression of thermal degradation was photographically documented throughout the destructive stages for soft tissues and bone to establish expected burn sequence patterns for the head. In addition to testing intact vaults, a percentage were selectively traumatized to introduce the variables of soft tissue disruption, fractures, impact marks, and incisions throughout the cremation process. Skeletal materials were recovered, reconstructed, and correlated with photographs to discern burn patterns and survivability of traumatic features. This study produced two important results: (1) Identification of preexistent trauma is possible in reconstructed burned cranial bone. Signatures of ballistic (internal and external bevel, secondary fractures), blunt force (impact site, radiating fractures), and sharp force (incisions, stabs, sectioning) survive the cremation process. (2) In non-traumatized specimens, the skull does not explode from steam pressure but does fragment as a result of external forces (collapsed debris, extinguishment methods) and handling. The features of both results are sequentially described throughout the progression of thermal destruction.     

Identification of traumatic injury in burned cranial bone: an experimental approach.

Interpreting patterns of injury in victims of fire-related deaths poses challenges for forensic investigators. Determining manner of death (accident, suicide or homicide) using charred remains is compounded by the thermal distortion and fragmentation of soft and skeletal tissues. Heat degrades thin cranial structures and obscures the characteristic signatures of perimortem ballistic, blunt, and sharp force trauma in bone, making differentiation from thermal trauma difficult. This study documents the survivability and features of traumatic injury through all stages of burning for soft tissue reduction and organic degradation of cranial bone. Forty cadaver heads were burned in environments simulating forensic fires. Progression of thermal degradation was photographically documented throughout the destructive stages for soft tissues and bone to establish expected burn sequence patterns for the head. In addition to testing intact vaults, a percentage were selectively traumatized to introduce the variables of soft tissue disruption, fractures, impact marks, and incisions throughout the cremation process. Skeletal materials were recovered, reconstructed, and correlated with photographs to discern burn patterns and survivability of traumatic features. This study produced two important results: (1) Identification of preexistent trauma is possible in reconstructed burned cranial bone. Signatures of ballistic (internal and external bevel, secondary fractures), blunt force (impact site, radiating fractures), and sharp force (incisions, stabs, sectioning) survive the cremation process. (2) In non-traumatized specimens, the skull does not explode from steam pressure but does fragment as a result of external forces (collapsed debris, extinguishment methods) and handling. The features of both results are sequentially described throughout the progression of thermal destruction.     

Resolving Reflection and Resolution in 3D Imaging of Fresh Bone

Structured light scanning is a noninvasive, accurate, and cost-effective 3D imaging technique, but due to reflection issues is yet to be utilized for tool mark analysis on fresh bone. During imaging, reflection from shiny surfaces, such as greasy bone, disrupts image formation. This study tested the David SLS-1 scanner's ability to image saw marks and explored six strategies to reduce reflection by [1] dulling the surface or [2] altering the projected light. The surface was dulled by freezing, talcum powder, dulling spray, or compressed air. The projected light was altered with a diffuser or limited to single pattern-coded. Results demonstrated that the resolution was insufficient for capturing minute details of striae. All six tests failed to reduce reflection sufficiently to produce complete images, but projecting vertical pattern-coded light showed the most promise. Future research is required concentrating on enhancing resolution and exploring the role of pattern-coded light in reducing reflection.     

An Anthropological Examination of the Types of Skeletal Fractures Resulting from Fatal High (˃3 m) Free Falls,

Fatal falls from heights (?3 m) often result in blunt force trauma (BFT) to the skeleton. The fracture patterns that result from this BFT mechanism are well understood in forensic anthropology and forensic pathology; however, details of the specific types of fractures that result remain poorly documented. The aim of this study was to provide a detailed examination of the types of fractures that may result from fatal high falls. Fractures were recorded from 95 full‐body postmortem computed tomography scans of individuals known to have died from a high fall. Trauma was then analyzed taking into account the extrinsic and intrinsic variables known to influence a fall using multiple logistic regression. A total of 339 types of fractures were classified, of which 16 were significantly associated with this BFT mechanism. Classified fracture types will augment anthropological interpretations of the circumstances of death from BFT in cases of suspected high falls.     

Discrimination of Falls and Blows in Blunt Head Trauma: Assessment of Predictability Through Combined Criteria*

Abstract: The discrimination of falls from homicidal blows in blunt head injuries is a common but difficult problem in both forensic anthropology and pathology. Three criteria have been previously proposed for this distinction: the hat brim line rule, side lateralization of fractures, and number of lacerations. The aim of the present study was to achieve a better distinction rate by combining those criteria and assess the predictability of these combined criteria tools. Over a 6‐year period, a total of 114 cases (92 males and 22 females) were studied: 21 cases of downstairs falls, 29 cases of falls from one’s own height, and 64 cases of head trauma by a blunt weapon. The results revealed predictability rates varying from 62.5 to 83.3% for criteria pointing towards a fall. As for combined criteria in favor of a blow, the assumption was accurate in all cases (100%).     

The Difficult Task of Assessing Perimortem and Postmortem Fractures on the Skeleton: A Blind Text on 210 Fractures of Known Origin

The distinction between perimortem and postmortem fractures is an important challenge for forensic anthropology. Such a crucial task is presently based on macro‐morphological criteria widely accepted in the scientific community. However, several limits affect these parameters which have not yet been investigated thoroughly. This study aims at highlighting the pitfalls and errors in evaluating perimortem or postmortem fractures. Two trained forensic anthropologists were asked to classify 210 fractures of known origin in four skeletons (three victims of blunt force trauma and one natural death) as perimortem, postmortem, or dubious, twice in 6 months in order to assess intraobserver error also. Results show large errors, ranging from 14.8 to 37% for perimortem fractures and from 5.5 to 14.8% for postmortem ones; more than 80% of errors concerned trabecular bone. This supports the need for more objective and reliable criteria for a correct assessment of peri‐ and postmortem bone fractures.     

Microscopic Pattern of Bone Fractures as an Indicator of Blast Trauma: A Pilot Study

The assessment of fractures is a key issue in forensic anthropology; however, very few studies deal with the features of fractures due to explosion in comparison with other traumatic injuries. This study focuses on fractures resulting from blast trauma and two types of blunt force trauma (manual compression and running over), applied to corpses of pigs; 163 osteons were examined within forty fractures by the transmission light microscopy. Blast lesions showed a higher percentage of fracture lines through the Haversian canal, whereas in other types of trauma, the fractures went across the inner lamellae. Significant differences between samples hit by blast energy and those runover or manually compressed were observed (p < 0.05). The frequency of pattern A is significantly higher in exploded bones than in runover and compressed. Microscopic analysis of the fracture line may provide information about the type of trauma, especially for what concerns blast trauma.     

A Preliminary Assessment of the Identification of Saw Marks on Burned Bone*

Abstract: This study assesses the degree of modification to the saw mark characteristics of dismembered skeletal remains when exposed to a controlled outdoor fire of limited duration. The sample consists of 36 adult pig hind limbs which were dismembered fleshed. Six handsaws and six power saws were used, with three limbs dismembered and burned for each of the saw types. Results indicate that fire exposure affects the visibility and identifiability of saw mark striae. With the handsaws, the bow saw, hacksaw, and keyhole saw were consistently recognizable. In the power saw group, the saw marks of the jigsaw, reciprocating saw, and chainsaw remained identifiable. Although the bone ends exhibited thermal alterations, the false starts were well preserved with minimal damage. Given the parameters of this study, it is possible to identify the class of saw based on the diagnostic characteristics present on the cremated bones.     

A Preliminary Investigation into the Accuracy of 3D Modeling and 3D Printing in Forensic Anthropology Evidence Reconstruction,

There is currently no published empirical evidence‐base demonstrating 3D printing to be an accurate and reliable tool in forensic anthropology, despite 3D printed replicas being exhibited as demonstrative evidence in court. In this study, human bones (n = 3) scanned using computed tomography were reconstructed as virtual 3D models (n = 6), and 3D printed using six commercially available printers, with osteometric data recorded at each stage. Virtual models and 3D prints were on average accurate to the source bones, with mean differences from ?0.4 to 1.2 mm (?0.4% to 12.0%). Interobserver differences ranged from ?5.1 to 0.7 mm (?5.3% to 0.7%). Reconstruction and modeling parameters influenced accuracy, and prints produced using selective laser sintering (SLS) were most consistently accurate. This preliminary investigation into virtual modeling and 3D printer capability provides a novel insight into the accuracy of 3D printing osteological samples and begins to establish an evidence‐base for validating 3D printed bones as demonstrative evidence.     

Assessment of Wear‐Related Features of the Kerf Wall from Saw Marks in Bone*†

Abstract: Analyses of saw marks in bone may yield important information about the class characteristics of saws used in postmortem dismemberments, yet little research has been directed at identifying saws’ individualizing characteristics. This study adds to existing saw mark analysis methodologies by examining wear‐related features of kerf walls using light‐ and environmental scanning electron microscopy. A crosscut saw and hacksaw were used to create sequences of 30 cuts in bone; these sequences reveal patterns of progressive loss of fine details of kerf wall morphology with increasing saw blade wear, because of the rounding of sharp points and edges. Nevertheless, diagnostic kerf wall features used to establish class characteristics persist despite these wear‐related changes. Unsuccessful attempts at statistical analysis of wear‐related changes, based on striae width and density, suggest these patterns are not readily quantifiable. Additionally, despite the scanning electron microscope’s superior imaging capabilities, it provided few practical, methodological gains over traditional light microscopy.     

Manners of Killing and Rituals in Apulian Mafia Murders*

Abstract: The Apulian (South of Italy) territory saw the birth of a criminal organization called Sacra Corona Unita (SCU, United Holy Crown) which transformed the rules of traditional mafia organizations. This work examined 83 victims of the SCU between 1980 and 2000. The bodies were mainly of SCU members and in some cases, of police and law enforcement officers and other citizens caught in the crossfire. Some of these were discovered; thanks to the collaboration of “repented” SCU members who became police informers. The condition of the bodies varied in relation to the date and manner of killing. In some cases anthropometric research methods were necessary. In 73% of the cases, lesions of the head were the only marks left on the body. In conclusion, the existence of some social aspects connected with the symbolisms and membership rites that characterized the origin, evolution, and decline of the SCU is stressed.     

Comparison of wound patterns in homicide by sharp and blunt force

A comparison of patterns of injuries between sharp force and blunt force homicide was performed. Male predominance was seen in both types of homicides. Most of the victims of sharp force were between 21 and 40 years and those of blunt force between 31 and 40 years. There was no difference in the incidence of victims below 20 years age, but blunt force was almost five times more than sharp force in victims of age above 60 years. Thorax was the commonest site to be involved in sharp force in contrast to head in blunt force. Hand and forearm were the commonest sites of defence injuries in sharp and blunt force homicides, respectively. The majority of the blunt force victims had lesions in only one region in contrast to involvement of 2-4 regions in sharp force. The majority of the victims were killed by acquaintances in blunt force, but criminals always prefer sharp force to kill their victims. Single weapon was more commonly used in blunt force as compared to sharp force. Knife and wooden/iron rods were the weapons of choice in their respective categories. Most of the victims of sharp force were killed outdoor in contrast to victim's own domicile in blunt force.     

A method for defleshing human remains using household bleach

Medical examiners and forensic anthropologists are often faced with the difficult task of removing soft tissue from the human skeleton without damaging the bones, teeth and, in some cases, cartilage. While there are a number of acceptable methods that can be used to remove soft tissue including macerating in water, simmering or boiling, soaking in ammonia, removing with scissors, knife, scalpel or stiff brush, and dermestid beetles, each has its drawback in time, safety, or potential to damage bone. This technical report using the chest plate of a stabbing victim presents a safe and effective alternative method for removing soft tissue from human remains, in particular the chest plate, following autopsy, without damaging or separating the ribs, sternum, and costal cartilage. This method can be used to reveal subtle blunt force trauma to bone, slicing and stabbing injuries, and other forms of trauma obscured by overlying soft tissue. Despite the published cautionary notes, when done properly household bleach (3-6% sodium hypochlorite) is a quick, safe, and effective method for examining cartilage and exposing skeletal trauma by removing soft tissue from human skeletal remains.     

Scavenger Species-typical Alteration to Bone: Using Bite Mark Dimensions to Identify Scavengers

Scavenger-induced alteration to bone occurs while scavengers access soft tissue and during the scattering and re-scavenging of skeletal remains. Using bite mark, dimensional data to assist in the more accurate identification of a scavenger can improve interpretations of trauma and enhance search and recovery methods. This study analyzed bite marks produced on both dry and fresh surface deposited remains by wild and captive red fox (Vulpes vulpes) and Eurasian badger (Meles meles), as well as domestic dog (Canis familiaris). The bite marks produced by foxes were distinguishable from those made by badgers and dogs based on ranges of mean length and breadth of pits. The dimensional data of bite marks produced by badgers and dogs were less discernible. Bone modifications vary due to a variety of factors which must be considered, such as scavenger species-typical scavenging behavior, scavenger species' dentition, condition and deposition of remains, and environmental factors.     

Rolando骨折成伤机制的法医学研究

目的研究与分析第一掌骨基底部Rolando骨折成伤原因，拟为法医学解决相应类型案件提供技术帮助与科学证据。方法对49例形成原因无争议的Rolando骨折临床病历资料进行整理分析，对21例尸体双手第一掌骨不同部位进行钝性打击实验以观察骨折类型及形态，综合分析Rolando骨折成伤原因。结果临床病历资料统计分析及法医尸体打击实验均证实第一掌骨基底Rolando骨折系拇指屈曲内收时偏桡侧作用于第一掌骨头部并沿掌骨长轴传导的轴向暴力作用所致；Rolando骨折断面呈T形或Y形，骨折线通过第一掌腕关节。结论第一掌骨基底Rolando骨折系拇指屈曲内收时偏桡侧作用于第一掌骨头部并沿掌骨长轴传导的轴向间接暴力作用所致。     

Fracture Characteristics of Entrapped Head Impacts Versus Controlled Head Drops in Infant Porcine Specimens,,

In many forensic cases, the job of forensic pathologists and anthropologists is to determine whether pediatric death is due to an abusive act or an accidental fall. The goal of this study was to compare the cranial fracture patterns generated on the parietal bone of a developing, infant porcine (pig, Sus scrofa) model by a controlled energy head drop onto a plate versus previous data generated by blunt force impact at the same energy onto the head constrained to a plate. The results showed that blunt force impacts on a head constrained to a rigid plate produces more fracture, but the same general pattern, as that for a head dropped onto the plate with the same level of impact energy. The study suggests that head constraint may be an important factor to consider in the evaluation of death causation for blunt force impacts to the pediatric skull.     

钝器致鼻部骨折95例法医学分析

目的探讨钝器致鼻部骨折种类、骨折及其修复的X线与CT表现差异等特点,为鉴定实践提供参考。方法对福建省古田县1999年1月至2013年12月发生的95例成年人因钝器致鼻部骨折的实际案例,按基本情况、骨折部位、致伤方式、确诊方式、鉴定意见等信息进行描述性统计,并对不同损伤根据新旧标准得出的鉴定意见进行比对。结果 95例成年人中,男性87例,女性8例,骨折部位、数量与鼻骨解剖关系、受力大小和方向均有明显的关联,复合性骨折多见,X线检查无法确定的骨折,经CT检查均可明确诊断。不同骨折类型按新旧标准鉴定意见有所不同。结论鼻部骨折数存在性别差异,外力大时易出现复合性骨折,CT检查明显优于X线检查。     

Three dimensional visualization and comparison of impressions on fired bullets

Currently, optical devices, such as microscopes and CCD cameras, are utilized for identification of bullets and tool marks in the field of forensic science. While these optical methods are easily manageable and effective, they are under great influence of illumination condition. In other words, appearances of striations through these optical devices have possibility to be changed by lighting condition. Besides these appearance-based approaches, we can utilize three dimensional (3D) geometric data of tool marks that are free from lighting condition. In this study, we focused on 3D geometric data of landmark impressions on fired bullets for identification. We obtained the 3D surface data of tool marks by a confocal microscope and reconstructed virtual impressions on a PC monitor from the geometric data. Furthermore, the 3D data are exploited to numerical matching of two surface shapes. We also visualized the difference of two shapes. In order to do this, two surface models are aligned automatically. In this process, pairings of correspondent points on both surfaces are determined. Distance analysis between these pairs leads to a shape comparison. Since comparison results are visualized, they are intuitive and easily perceptive.     

Wounds inflicted by survival-knives

A homicidal fatality is presented to demonstrate that the pattern of injuries may suggest the use of an unusual sharp force, a survival-knife, the characteristics of which are in any case well defined. This knife has saw teeth along the back that can leave characteristic scrape marks on the skin.