Validity of the use of porcine bone in forensic cut mark studies

Porcine bone is often used as a substitute for human bone in forensic trauma studies, but little has been published on its comparative mechanical behavior. The factors affecting mechanical properties and therefore selection of bone models are complex and include the age of the animal at death, and physiological loading conditions, the latter being of particular relevance when using a quadrupedal animal as a human substitute. The regional variation in hardness of adult and infant porcine bones was investigated using Vickers’ indentation tests and compared to published data for human limb bones to relate differences to inherent genetic effects and loading influences, and to examine the validity of the porcine‐human model. Significant differences in hardness were observed both along and around the adult porcine humerus and femur, but no significant differences were found along the length of the infant bones. Significant differences were found between the forelimb and hindlimb, but only in the infant specimens. The hardness values for porcine adult cortical bone from the femur (52.23 ± 1.00 kg mm^?2) were comparable to those reported in the literature for adult human cortical bone from the fibula, ilium, and calcaneus. These data will help inform subject selection in terms of both species and bone type for use in future trauma studies.     

Analysis of histomorphometric variables: Proposal and validation of osteon definitions

Histological analysis of bone tissue has been used to explore a variety of questions relating to age-at-death, habitual behaviors, health, and nutritional stress. Identification of intact and fragmentary osteons is of key interest to many researchers in these studies, yet the definitions of these features vary between researchers making cross-study comparisons problematic. Furthermore, histological variable definitions are often ambiguous or require subjective classifications by the observer. As a result, and as indicated by previous studies, observer error and misclassification of certain variables, namely intact and fragmentary osteons, can be significant. This study proposes new definitions for intact and fragmentary osteons that are designed to limit observer subjectivity and also explore efficacy of combining osteon types into one variable. A sample of 30 6th rib cross-sections from a modern forensic population was used to test the validity of the proposed definitions. Observations of intact osteon population density (OPD(I)) and fragmentary osteon population density (OPD(F)) were made by three observers for each cross-section. These observations were used to explore the interobserver error associated with the proposed definitions and determine if combining variables into one variable (OPD) mitigates persisting classification difficulties. Results indicate that the proposed definitions significantly reduce interobserver error and misclassification of intact and fragmentary osteons. However, the interobserver error associated with fragmentary osteons is still high. Evaluation of the variables independently indicates that combining variables has potential to reduce the predictive strength of an age estimation model and the ability to interpret age-related bone remodeling.     

Gunshot residues on dry bone after decomposition-a pilot study

Abstract: Very little literature exists concerning radiochemical and microscopic analyses of gunshot wounds in decomposed material, and even less concerning skeletonized samples; the most advanced technologies may provide useful indications for the diagnosis of suspect lesions, especially if gunshot wounds are no longer recognizable. However, we know very little of the survival of gunshot residues (GSR) in skeletonized samples. This study examined nine gunshot wounds produced on pig heads which then underwent skeletonization for 4 years, and four gunshot entries on human heads from judicial cases which were then macerated to the bone in water; the samples underwent scanning electron microscopy coupled with energy dispersive X‐ray (SEM‐EDX) analysis. Positive results for GSR were observed only in four of the nine animal samples and in all four human samples. Among the human samples, two lesions showed Pb and Sb, one lesion only Pb, and one Pb, Sb, and Ba. This pilot study showed the survival of GSR in skeletal material and therefore the crucial importance of SEM‐EDX analyses on skeletonized material. Further studies are needed in order to ascertain the role of environmental modifications of GSR.     

An investigation of model forensic bone in soil environments studied using infrared spectroscopy

Infrared spectroscopy has been used to examine changes to bone chemistry as a result of soil burial. Pig carcasses were buried as part of a controlled field study, and pig bone was used in soil environments established in the laboratory. The variables of species type, bone pretreatment, soil type and pH, moisture content, temperature, and burial time were investigated. The crystallinity index (CI) and the organic and carbonate contents of the bones were monitored. The data revealed decreasing trends in the organic and carbonate contents and an increase in the CI of the bone with burial time. An acidic soil environment and soil type are the factors that have the most influence on bone chemistry as a result of burial. The study demonstrates the potential of infrared spectroscopy as a straightforward method of monitoring the changes associated with aging of bones in a variety of soil environments.     

Human coxal bone sexual dimorphism and multislice computed tomography: geometric morphometric analysis of 65 adults

The authors studied sexually dimorphic differences in coxal shape using geometric morphometric analysis of 15 osteometric landmarks recorded by multislice computed tomography (MSCT), based on three-dimensional reconstructions of 65 Caucasian adults. Geometric morphometric analysis, principal component analysis, canonical variates analysis, and other discriminant analysis (Goodall's F-test and Mahalanobis distance) were performed for the three separate bones of the left innominate (pubis, ilium, and ischium), the modified pubis (pubis and ischiopubic ramus), the modified ilium (ilium and ischial spine), three bone complexes (ischiopubic, iliopubic, and ilio-ischial), and the complete innominate. A cross-validation test was also performed. All areas studied were dimorphic, but results for sexual dimorphism in decreasing order were as follows: the modified pubis, followed by the ischiopubic complex, the iliopubic complex and the complete innominate, the pubis, the modified ilium, the ilio-ischial complex, the ilium, and finally the ischium. These results show the potential of this approach for future anthropological research.     

TW2、TW3法腕骨骨龄评价方法的诊断性试验

目的比较TW2法英国人标准、TW2法中国人南方标准和TW3法测定腕骨骨龄对特发性性早熟(IPP)女孩的诊断价值。方法女性IPP患儿55例;对照组83例。回顾性分析初诊左腕X线片,用TW2法、TW2CHC中国人南方标准和TW3法盲法分期,分别测得其腕骨骨龄及其百分位,并分为5个连续性的工作点,即:>P97、>P90、>P75、>P50和、≤P50。结果敏感度(Sen)和特异度(Spe)都比较高的有以下3个工作点:TW2CH“>P90”点,TW3“>P90”点,TW2“>P90”点。结论TW系统3种腕骨骨龄对于IPP女孩都有诊断价值,TW3法和TW2法中国人南方标准诊断价值比较高,TW2法英国人标准的诊断价值为中等。     

中国汉族人耻骨性别判定的研究

目的为了探讨耻骨性别判定的更为简便可靠的方法。方法对96副已知生前确切性别的耻骨进行了性别差异的研究,其中男性耻骨73副,女性耻骨23副。测量项目有:缘枝角,耻骨宽,耻骨联合面的高及厚。结果将耻骨的测量数据输入电脑,用SPSS软件,对耻骨的测量数据进行了统计分析,建立了耻骨性别判定的判别方程。结论其性别判别率最高可达95.5%,该方法可以用于法医学实践。     

3种骨骼DNA提取方法的应用效果比较

目的对3种方法提取骨骼DNA的效果进行比较,为实际应用中选择方法提供参考。方法应用骨骼孵化液法、DNA Investigator试剂盒法和CTAB法对同一骨骼样本进行脱钙、消化、提取DNA,用紫外分光光度计检测DNA的浓度值;使用Identifilerplus试剂盒进行PCR扩增,3130xl型遗传分析仪检测分型,并用SPSS 19.0软件对各项实验结果进行统计分析。结果 1g骨粉样本经上述3种方法提取,得到的DNA浓度分别为26.53ng/μL±5.47ng/μL、23.63ng/μL±4.56ng/μL、14.93ng/μL±3.88ng/μL;单因素方差分析表明3组数据之间差异性具有统计学意义。PCR扩增后电泳检测结果显示,骨骼孵化液法和DNA Investigator试剂盒法基因座检出率和峰值大致相同,均优于CTAB法。结论本文比较的3种方法均可用于骨骼样本的实际检案,检出率较高的两种方法可作为优选方案。     

246例高坠案件中坠落高度与损伤分析

目的对高坠案件进行统计分析,为相关鉴定研究提供参考。方法收集上海市浦东地区最近十年来记录有坠落距离的246例高坠案件,对人体损伤的特点进行比较分析。结果自杀高坠的高度显著高于意外高坠的高度(25.70m:13.98m);所有高坠中,头部损伤概率较高(75.2%),颈部损伤概率较低(6.5%);意外高坠的头部损伤概率高于自杀组(89.4%:75.2%)。结论意外高坠的死者比自杀高坠的死者更缺乏四肢对于头部的保护;过低的颈部损伤发现率提示国内法医工作者应该更加重视在高坠案件中的对于颈部损伤的检查。     

A New Method for Determination of Postmortem Interval: Citrate Content of Bone*

Abstract: Few accurate methods exist currently to determine the time since death (postmortem interval, PMI) of skeletonized human remains found at crime scenes. Citrate is present as a constituent of living human and animal cortical bone at very uniform initial concentration (2.0 ± 0.1 wt %). In skeletal remains found in open landscape settings (whether buried or not), the concentration of citrate remains constant for a period of about 4 weeks, after which it decreases linearly as a function of log(time). The upper limit of the dating range is about 100 years. The precision of determination decreases slightly with age. The rate of decrease appears to be independent of temperature or rainfall but drops to zero for storage temperature <0°C.