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。     

烧骨个体识别的研究进展

烧骨DNA检测在火灾、焚尸、爆炸等事故中的个体识别和亲权鉴定方面,发挥着越来越重要的作用。STR作为重要的遗传标记系统,已广泛应用于法医学个体识别、亲权鉴定等领域。本文从焚烧温度及时间对烧骨STR分型的影响、烧骨STR基因座的选择和烧骨DNA的提取方法三个方面结合目前的研究进展进行了概述。     

民用取暖炉焚尸骨骼残渣的法医学检验

对杀人焚尸案中的碳化尸体及烧骨残片如何进行法医学检验已有报告，对烧骨残渣做DNA检验进行身源鉴定也有专门的研究，但是，如果烧骨的有机质全部消失，骨骼残渣破碎严重，则进行法医学鉴定难度较大。     

桡血管沟影误为桡骨骨折线一例分析

在临床实践及法医检案中常会遇到因为闽片人对骨解剖及正常变异的X线影象不了解，而将骨曲正常变异的X线担象误认为骨折线的情况。现将一例烧血管沟误认为挽骨骨折的案例报告如下：塞话摘星韩某，女，32岁。既往体健，无外伤史。自诉：1994年2月25日晨8时许，推自行车上班途中被一块砖头击中左前＊。当时感左前＊疼痛难忍，活动受限。使前在某大医院诊治。经对受伤部位行X线摄影，诊断为外伤性左挠骨中上段骨折。受当地公安机关的委托，对其左前＊的损伤进行了临床法医学鉴定。活体检验所见及法医学鉴定结论：伤着韩某，年轻女性，步入诊…     

45例眶骨骨折法医学鉴定的探讨

眼眶骨组织因结构的特殊性,眼部受钝性暴力作用后,极易造成眶骨骨折。本文现对受理的45例眶骨骨折法医学鉴定进行分析和探讨。1一般资料45例眶骨骨折,均由CT检查确诊。其中左眼眶内壁(筛板)骨折18例,右眼眶内壁骨折21例(包括同时双侧眼眶内壁骨折3例),眶下壁4例(左眼1例,右眼3例),外侧壁骨折1例,眶外壁、眶下壁及眶内壁合并骨折1例。眶内壁骨折40例占眶骨骨折例数的88.89%。眶骨骨折伴眶内、皮下积气32例,占眶骨骨折例数的71.11%,眶骨骨折相邻窦腔积血33例占眶骨骨折例数的73.33%。眶骨骨折伴球结合膜下出血38例,占眶骨骨折例数的84.44%。…     

利用放射性核素骨显像检查鉴别鼻部骨折新旧程度回顾性法医学分析

目的 利用放射性核素骨显像检查鉴别鼻部骨折的新旧程度.方法 对48例疑似陈旧性鼻部骨折伤者放射性核素全身骨显像、局部断层骨显像及CT融合图像在鼻部骨折处放射性分布、浓聚情况的分析,鉴别鼻部骨折的新旧程度.结果 48例中8例放射性核素全身骨显像、局部断层骨显像及CT融合图像在鼻部骨折处显示放射性分布增高、浓聚区,诊为新鲜骨折,评定为轻伤;40例在鼻部骨折处未见明显异常放射性分布增高、浓聚区,诊为陈旧骨折,与本次外伤无因果关系.结论 放射性核素骨显像检查在鉴别鼻部骨折新旧程度方面可得到满意结果.     

生理性小骨骺分离的影像学观察及其与骨端骨折的鉴别研究

目的探讨生理性小骨骺分离的影像学特征及其与骨端撕脱性小骨折片的鉴别方法。方法回顾性分析21例怀疑骨端骨折而行法医学鉴定的案例,通过观察骨端游离小骨周边是否存在连续的骨皮质、小骨片相对侧表面是否有连续的骨皮质和局部软组织肿胀情况,并结合损伤机理考察骨折形态。结果21个案例中,6例游离小骨片与相对侧骨表面呈锐利的骨折线,并缺乏连续的骨皮质,周边可见软组织肿胀,考虑骨端撕脱小骨折;15例游离小骨与相对侧骨表面存在连续性骨皮质,考虑为骨关节端永存分离性小骨骺。观察游离小骨周边和相对侧骨表面是否有骨皮质,高分辨CT可以获得满意的结果;观察小骨周边相应的软组织肿胀,MRI较好。结论通过对骨端游离小骨详细的影像学观察,有助于鉴别骨折与生理性小骨骺分离。     

管状骨扭转外力性骨折的形态学分析

在民事纠纷和刑事伤害案件中,人体四肢管状骨扭转外力所造成的骨折,往往因双方当事人大相径庭的陈述.使法医对骨折致伤方式的推断增加了难度。为此,作者对四肢管状骨扭转外力性骨折的形态和骨折角,进行了回顾性分析。资料     

68例长管状骨不规则骨折法医学分析

长管状骨骨折在法医损伤鉴定中是一种较常见的肢体损伤。本文报告的不规则骨折类型主要是指斜形、横斜形、蝶形、螺旋形和粉碎形骨折。不同的骨折形态与致伤原因有着密切的联系。本文通过对68例长管状骨骨折的统计分析,着力从法医力学角度探讨损伤因素与骨折类型产生之间的关系等,现总结如下。     

管状骨扭转性骨折的法医形态学分析

本文对１９８５年１０月至１９９４年３月，作者对所办理的９８８例案件中的３２例四肢管状骨扭转骨折的形态学进行了分析。结果表明：其骨折形态有７２％呈螺旋形，２８％呈斜形；骨折角平均为２６．８°，与４５°的传统标准差异显著。作者认为：影响骨折角的原因很多，除与骨骼成份、结构和复合加载等因素有关外，骨骼组织并不服从虎克力学定律，是造成显著差异的主要因素，因而认为骨折角不是恒定的常数而是变量，４５°的传统标准需要在实践中进一步验证。另外，作者对管状骨扭转骨折的生物力学也进行了探讨。     

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.     

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.     

烧骨残片种属鉴定的研究

为了找出常见动物骨骼焚烧残片的种属鉴定方法,笔者对猪、羊,股骨及肱骨的断端,猪、羊、牛颅骨的残片(额顶部),焚烧后进行了观察及测量,并与人类股骨、肱骨及焚烧的颅骨残片进行了比较.结果发现,长骨滋养孔的位置,骨干骨壁厚度,以及颅骨厚度,颅缝形态及内板表面特征等方面,是鉴定骨骼残片种属的有价值的特征.根据对常见动物长骨及颅骨残片的现察及研究,提出了骨骼残片种属鉴定的方法.     

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.     

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.     

Craniometric diagnosis of skeletal and somatotype mass

The paper presents diagnostic models for evaluation of ash mass (bone fragments, bone ashes), sex, length and mass of the burned body. Individual data by M. Warren and W. Maples (1997) on 85 adult Americans were used. On the basis of a canonical discriminant analysis and multiple linear regression equations the authors have developed models for diagnosis of ash residue mass as well as the burned body's sex, body length and mass. The above models can be used directly on the place of the criminal body cremation. They do not require determination of anatomic appurtenance of bone fragments and their osteometric examination.     

X‐ray Scattering Evaluation of Ultrastructural Changes in Human Dental Tissues with Thermal Treatment

Micro‐ and ultrastructural analysis of burned skeletal remains is crucial for obtaining a reliable estimation of cremation temperature. Earlier studies mainly focused on heat‐induced changes in bone tissue, while this study extends this research to human dental tissues using a novel quantitative analytical approach. Twelve tooth sections were burned at 400–900°C (30‐min exposure, increments of 100°C). Subsequent combined small‐ and wide‐angle X‐ray scattering (SAXS/WAXS) experiments were performed at the Diamond Light Source synchrotron facility, where 28 scattering patterns were collected within each tooth section. In comparison with the control sample, an increase in mean crystal thickness was found in burned dentine (2.8‐fold) and enamel (1.4‐fold), however at a smaller rate than reported earlier for bone tissue (5–10.7‐fold). The results provide a structural reference for traditional X‐ray scattering methods and emphasize the need to investigate bone and dental tissues separately to obtain a reliable estimation of cremation temperature.     

A microscopic comparison of fresh and burned bone.

Examination of the microstructure of human bone is useful in estimating age at death in forensic science cases. This technique has been tested and is well accepted, however samples of burned bone may complicate analysis because of possible changes in the microstructure occurring during the burning process. In a comparison of fresh and burned ground thin sections taken from midshaft femorae of eight dissecting-room cadavers of known age and sex, this study finds significant shrinkage of microstructural elements through the burning process. These results are compared to previous work on the subject, which found the microstructural elements to increase through the burning process.