Chemical trace XRF analysis to detect sharp force trauma in fresh and burned bone

Forensic anthropologists may not always be able to differentiate heat-induced fractures from fractures with other aetiologies, namely sharp force traumas, with clear nefarious impact on medico-legal conclusions. The objective of this study was to experimentally investigate if blade chemical traces are transferred to defleshed bone tissue and if they remain there after a burning event. This was accomplished by prompting sharp force traumas in 20 macerated fresh pig ribs with five different instruments, namely a stainless steel knife, an artisanal knife and a ceramic kitchen knife, a small axe and a large axe. Another pig rib was used as control, not being subjected to any trauma. All instruments were probed by X-ray fluorescence (XRF) to establish the composition of each blade. Bone samples, both pre-burned and post-burned (at 500 °C, 700 °C, 900 °C and 1100 °C), were then probed by XRF. All sharp force instruments left detectable chemical traces on pre-burned bone, although not in all samples. Furthermore, traces were still detected after experimental burning in most cases. Potentially, XRF can provide relevant information about the aetiology of fractures in burned and unburned bones, although the effect of soft tissues and diagenesis must still be investigated.     

烧骨的研究现状与展望

本文根据国内外相关文献,对烧骨的宏观、微观形态学特点,烧骨形态特征与各影响因素之间的关系,热致骨折与损伤骨折、条件性骨折的鉴别等方面进行了综述,并对现有研究的局限之处进行了分析,提出改进方向。     

The differentiation of traumatic and heat-related fractures in burned bone.

Interpretations of antemortem and perimortem trauma are complicated when dealing with cases involving extreme exposure to fire. This investigation attempts to discern the signatures of perimortem trauma from heat related trauma. Femora of domestic pig, sus scrofa, with minimal soft tissue and articulated patellae were subjected to varying traumatic forces. Skeletal elements were impacted with blunt and sharp forces, cut with varying instruments, subjected to torsional forces of shot. Bones were burned in various situations in conjunction with Knox County Rural/Metro Fire Department training exercises conducted in Knox County, Tennessee. Following recovery, fragments were subjected to radiographic, macroscopic, and microscopic analyses. Skeletal elements were reconstructed to permit accurate comparison with pre-fire visual records. In addition, fracture surfaces were examined under both transmitted light and scanning electron microscopy in an attempt to discern surface signatures of the causal fracture (trauma, heat, or situational). Results indicate that signatures of sharp force trauma remain evident following incineration. Furthermore, radiopaque spatter was not observed in any shot specimen. However, these initial findings suggest that the interpretation of blunt force and torsional trauma requires a rigorous examination and comparison of fracture patterns in conjunction with surface morphology.     

A simple and efficient method for extracting DNA from old and burned bone

It has been a challenge to extract DNA from bones previously soaked in water, burned, or buried for a long time, due to the reduced quality and quantity of DNA in the bone samples. The dramatic degradation of the DNA and the presence of PCR inhibitors in the collagen significantly complicate the process of DNA identification in dated and charred bones. In this article, we present a novel strategy to obtain DNA from bones based on the use of cetyltrimethylammonium bromide (CTAB) lysis buffer and isoamyl alcohol-chloroform extraction with subsequent DNA purification using the DNA IQ System, or alternatively the QIAquick system. When applied to bones soaked, burned or buried for up to nine years, this method increases the purity and yield of DNA with respect to the traditional phenol-chloroform method and significantly improves multiplex STR genotyping using fluorescence-based methods. The results of this research will assist forensic scientists in the identification of DNA from victims whose bodies underwent significant trauma or burning, precluding the utilization of traditional forensic DNA identification techniques.     

Forensic medical expertise on burned bone remains

The series of 1138 cadaveric humerus and femurs of people of both sexes who died at the age of 17-91 years and 468 animal bones (cow, pig, sheep) was studied. Bones were burned (experimentally) at various temperature values and in different conditions. Investigations were carried out using osteometric, microscopic, microroentgenographic and mathematical methods. Species identification as well as sex and age determination using burned bone remains are possible regardless of the level of their burning. Regression equations to calculate victim's stature according to fragments of burned bones were received.     

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.     

烧骨组织形态变化及DNA技术在个体识别中的应用

烧骨在火灾、焚尸、交通、爆炸等案件和事故的检材中具有特殊的地位。通过对不同条件焚烧下烧骨组织形态及DNA变化规律的研究,可为法医实践中烧骨的种属鉴定、性别及年龄判定提供准确的依据和标准,同时可利用残存的基因位点对烧骨残块进行个体识别和同一认定。烧骨DNA的提取方法及检测技术也在不断探索和改进。本文对烧骨在形态学、组织学和分子生物学水平研究进展以及烧骨评测的方法、技术进行概述,旨在为法医实践及进一步研究提供新的方法和思路。     

新鲜鼻骨骨折CT诊断指标探讨

法医鉴定工作中,需要明确判断鼻骨骨折为新鲜形成,方可作为人体损伤鉴定的依据.通过案例追踪复查与已知陈旧鼻骨骨折对照及临床表现等方法,依据骨折断端锐利、骨折部位粘膜肿胀、软组织内有小片状低密度影等CT影像表现,结合伤后鼻面部肿胀、鼻出血、鼻腔通气不畅等临床表现作为新鲜鼻骨骨折的影像诊断指标.工作中,须重视鼻骨骨折新旧伤的...     

A review of the current understanding of burned bone as a source of DNA for human identification

Identification of incinerated human remains may rely on genetic analysis of burned bone which can prove far more challenging than fresh tissues. Severe thermal insult results in the destruction or denaturation of DNA in soft tissues, however genetic material may be preserved in the skeletal tissues. Considerations for DNA retrieval from these samples include low levels of exogenous DNA, the dense, mineralised nature of bone, and the presence of contamination, and qPCR inhibitors. This review collates current knowledge in three areas relating to optimising DNA recovery from burned bone: 1) impact of burning on bone and subsequent effects on sample collection, 2) difficulties of preparing burned samples for DNA extraction, and 3) protocols for bone decalcification and DNA extraction. Bone decalcification and various DNA extraction protocols have been tested and optimised for ancient bone, suggesting that prolonged EDTA (Ethylenediaminetetraacetic acid) demineralisation followed by solid-phased silica-based extraction techniques provide the greatest DNA yield. However, there is significantly less literature exploring the optimal protocol for incinerated bones. Although burned bone, like ancient and diagenetic bone, can be considered “low-copy”, the taphonomic processes occurring are likely different. As techniques developed for ancient samples are tailored to deal with bone that has been altered in a particular way, it is important to understand if burned bone undergoes similar or different changes. Currently the effects of burning on bone and the DNA within it is not fully understood. Future research should focus on increasing our understanding of the effects of heat on bone and on comparing the outcome of various DNA extraction protocols for these tissues.     

Frozen human bone: a microscopic investigation

The taphonomic effects of prolonged extreme cold and freezing on human bone have received little research attention. Questions of specific interest include whether previously frozen bone can be identified and whether freezing alters the structural integrity enough to prevent histological aging. There is no evidence from previous studies that freezing damages the structural integrity, and to date no research investigating the freezing process on bone microstructure has been undertaken. This research attempts to distinguish histologically previously frozen bone from nonfrozen bone by identifying patterned defects. To determine the effects of freezing in bone microstructure using light and scanning electron microscopy (SEM), several human bone sections were subjected to prolonged freezing and allowed to thaw before thin sectioning. Light microscopy failed to demonstrate statistically significant differences between frozen and nonfrozen specimens. SEM analysis revealed fractures, although these lacked pattern and did not occur systematically throughout the section. Evidence of microstructural changes caused by liquid expansion, however, was remarkable but did not alter the structural integrity of the microstructure. The results of this study suggest that freezing does not alter the process of histomorphological analysis.     

Pericarotid bone splinter: a microscopic appearance in hanging

The investigation of the neck structures drawn from 145 cases of asphyxia involving pressure on the neck, for which microscopic examination was required at the Pathology Laboratory of the "Hotel Dieu" Hospital from Lyon, France, during January 1, 1999, to May 1, 2001, has pointed out in 3 cases, besides the classic signs already known, a particular lesion unmentioned yet in the literature, namely, a pericarotid bone splinter, placed in the proximity of the common carotid artery bifurcation. The bone splinters had dimensions between 0.25 and 0.7 mm and a certain antemortem character, surrounded by hemorrhagic areas and by fibrin. The 3 cases deal with adult males who had died through complete hanging, with the knot placed lateral, the hanging mark having the maximum depth in the laterocervical region, correspondent with our finding. Given the location of the bone splinter, we believe that this was produced by the tearing out from the transverse apophysis of the fourth cervical vertebra, as a consequence of the sudden traction during hanging. This sign appeared neither at other types of hanging nor at strangulation by hand or by ligature.     

Macroscopic observations of the effects of varying fresh water pH on bone

Little is known about the decomposition of remains in aquatic environments of varying pH, and even less is known about the specific effects of these environments on bone. Bovine bones were placed in solutions of pH 1, 4, 7, 10, and 14 and observed over a period of 1 year. All solutions eventually removed or dissolved the soft tissues from the external surface of the bone. The pH 7 and pH 10 solutions had little effect on the bone, but the other solutions affected the bone to varying degrees. Extreme pH levels were the most destructive, while more moderate pH levels had lesser but significant and interesting effects. Empirical data on postmortem aquatic changes may be extremely useful in forensic contexts for both improving time since death estimates and also for providing better information to underwater recovery experts thereby potentially increasing the quantity and quality of remains recovery.     

法律评价的重新解释

价值法学对法律评价概念的解释存在理论上的局限 ,难以揭示其本质特征。本文从科学认识论出发 ,把法律评价界定为社会主体对法律现象的事实、价值、审美判断三位一体的认识活动 ,并揭示了法律评价的主体性、主观性、法律性、现实性以及主体广泛性等特征。     

The forensic evaluation of burned skeletal remains: A synthesis

In recent years, research and case experience have greatly augmented knowledge regarding the effects of extreme heat on skeletal remains. As a result of this effort, enhanced interpretation is now possible on such issues as the extent of recovery, reconstruction, trauma, individual identification, size reduction, thermal effects on histological structures, color variation, the determination if remains were burned with or without soft tissue, DNA recovery and residual weight. The rapidly growing literature in this area of forensic science includes experimental research that elucidates the dynamics of the thermal impact on skeletal structure and morphology.