掌骨骨折致伤方式法医学鉴定附27例分析

目的探讨掌骨骨折的形成机制,为掌骨骨折致伤方式的法医学推断提供参考。方法通过对27例致伤方式明确的掌骨骨折案例进行回顾性分析．对不同部位、性质的掌骨骨折结合其致伤方式进行损伤机制分析,并分类统计。结果诸掌骨中以第5掌骨骨折最为常见。就部位而言,又以基底部骨折最为常见,多见于间接暴力传导作用所致;其次为掌骨颈骨折．往往为纵向暴力作用所致。常见于攻击伤、撞击伤;掌骨头骨折常见于握拳时暴力直接打击所致;掌骨体横行或粉碎性骨折为直接暴力作用所致．斜形或螺旋形骨折多为旋转暴力作用所致。结论根据掌骨骨折的部位、性质,通过分析其骨折的形成机制,可以推断其致伤方式,从而为司法鉴定提供有力证据。     

MRI在膝关节细微骨折法医学鉴定中的应用价值

目的探讨膝关节细微骨折的MRI表现及其在法医学鉴定中的应用价值。方法分析24例经MRI诊断并经CT及临床证实的膝关节细微骨折的MRI表现,并与CT和X线检查结果进行比对。结果24例患者中X线仅检出2处骨折,CT检出27处,MRI检出31处骨折;其中MRI诊断同一患者2处以上骨折共有5例。所有骨折均无明显分离或错位,T1WI STIR和FE-T2WI序列是显示细微骨折的最佳序列。结论MRI能明确诊断膝关节细微骨折,为法医学鉴定提供有力的依据。     

稳定型骨盆前环骨折移位伤残评定20例

目的探讨通过骨盆骨折移位距离来判定骨盆前环骨折畸形愈合。方法通过测量骨盆前环骨折伤者影像学资料的骨折移位最大距离;对20例被鉴定人进行回访,询问其遗留的症状。结果 20例中有14例(70%)骨盆前环骨折移位大于4mm;在16例接受回访的被鉴定人中,有12例(75%)长时间站立或行走后有盆部隐痛或明显疼痛症状。结论骨盆前环有两处或以上部位骨折且移位超过4mm,多数可考虑认定骨盆畸形愈合;骨盆前环单处骨折,移位超过6mm,可考虑认定骨盆畸形愈合。     

颅骨骨折断面细微结构的观察研究

作者利用扫描电子显微镜,对颅骨骨折断面上微细结构的形态学特征进行了观察与研究,发现在颅骨骨折断面上有微细的骨折裂线,向断面深部的骨质中延伸,其宽度为5至100um不等,主要分布在颅骨外板内,或外板与板障的交界处.分布于板障内的微细裂线可造成骨小梁横行、纵行和螺旋形骨折.骨折时,骨基质中的胶原纤维束可被分离或断裂,各胶原纤维层可分开.骨内血管可被骨折裂线横断或纵形撕裂,损伤的血管可被从哈佛氏管中拉出.生前骨折时,在微细裂线的深方可清楚见到纤维蛋白网和红细胞相互粘集,死后骨折则未见到此现象.本文还探讨了颅骨骨折发生的机理和推断生前骨折的可能性.     

Abusive Pediatric Thoracolumbar Fracture Due to Forced Hyperextension: Case Report,Biomechanical Considerations,and Review of the Literature

Pediatric thoracolumbar fractures are rare due to the physiological differences which afford greater resilience to the immature spine. Most pediatric thoracolumbar fractures occur as the result of high energy trauma, such as motor vehicle accidents, and modes of reasonable accidental injuries are limited by age and developmental capabilities of the child. These fractures can occur as the result of inflicted blunt force trauma and child abuse, and in most cases, the mechanism of injury to the spine is not known. We report the death of a 29-month-old man due to blunt force trauma to the back and forced hyperextension of the thoracolumbar spine causing fracture of the fourth lumbar (L4) vertebral body. A complete forensic examination revealed a previous healing fracture of the anterior aspect of the L4 vertebral body, with acute disruption of the anterior longitudinal ligament overlying the fracture site, complete fracture of the vertebral body, and fatal retroperitoneal hemorrhage. We present a review of the biomechanical considerations of the pediatric spine, a survey of pediatric spinal fractures, and a review of the literature on pediatric abusive thoracolumbar fractures. In this case, there was never a provided explanation for how the injury occurred; however, understanding the biomechanics of the pediatric spine allowed for the determination of the mechanism, force required to produce this specific pattern of abusive spinal injury, and the manner of death.     

掌骨骨折损伤程度及法医学鉴定

探讨掌骨骨折的致伤特点及活体损伤程度的法医学鉴定。对 5 2例掌骨骨折的案例资料按不同掌骨及损伤类型进行分析。第 1～ 5掌骨分别对于掌骨头、掌骨颈、掌骨干、掌骨基底部的骨折发生率和致伤机理各有不同 ,直接暴力所致第 2掌骨头、间接暴力所致第 5掌骨颈、第 3和 4掌骨干及第 1掌骨基底部等部位的骨折最常见。分析结果表明 ,掌骨骨折损伤程度不同 ,其损伤机理不同 ,各有其特点     

Perimortem or Postmortem Bone Fractures? An Experimental Study of Fracture Patterns in Deer Femora*

The determination of perimortem trauma is important for forensic anthropologists. Characteristics of bone fractures such as sharp edges, presence of fracture lines, the shape of the broken ends, fracture surface morphology, fracture angle on the Z-axis, and butterfly fractures are said to differentiate perimortem from postmortem trauma. A Drop Weight Impact Test Machine was used to break 76 deer femora of various ages since death. The results of this study suggest that the characteristics listed above are unreliable at differentiating a perimortem fracture from a postmortem fracture in a forensic case. There are, however, statistically significant differences between fresh bones broken less than 4 days old and dry bones broken 44 days or 1 year old after death.     

A Proposed Scheme for Classifying Pediatric Rib Head Fractures Using Case Examples

Pediatric rib head fractures are typically described as “posterior” or “costovertebral,” terms lacking specificity. To resolve this issue, a scheme was developed to describe the location of rib head fractures observed in a pediatric forensic population. The scheme uses three anatomical landmarks, terminus (tip), tubercle, and costovertebral articular surface to divide the rib head into two subregions, costovertebral and costotransverse. Examples of five cases of infants with rib head fractures are presented using this scheme. Forty‐eight rib head fractures were observed in these infants with the following frequencies: 56% (three infants) at the terminus; 21% (three infants) in the costovertebral subregion; 21% (one infant) at the costovertebral articular facet; and 2% (one infant) in the costotransverse subregion. Due to the small number of cases assessed, statistical analyses could not be performed; however, the data demonstrate the variation in distribution of pediatric rib head fractures.     

Physical Matching of Metals: Grain Orientation Association at Fracture Edge

The objective of this study was to examine whether surface crystal orientation can be used to associate or differentiate metal fracture fragments. The orientations of individual crystals and crystals across the fracture plane were measured on polished steel and iron alloy surfaces using Electron Backscattered Diffraction/ Orientation Imaging Microscopy (EBSD/OIM). This investigation examined crystallographic characteristics within a metal. This study showed that for transgranular fracture, it is feasible that pieces of grains could be associated across the fracture surface with the difference in orientation between grains (misorientation) along a length sequence of grain orientations on one side of the fracture surface to associate the other side of a fracture surface. Regarding pair comparisons of crystals on fracture surfaces, it was estimated that the probability for an ordered sequence of six distinct oriented grains along a fracture surface to occur again is about 1 in 4.82 (10)³⁰ or 2.07 (10)⁻³¹.     

Classification of Pelvic Ring Fractures in Skeletonized Human Remains

Pelvic ring fractures are associated with high rates of mortality and thus can provide key information about circumstances surrounding death. These injuries can be particularly informative in skeletonized remains, yet difficult to diagnose and interpret. This study adapted a clinical system of classifying pelvic ring fractures according to their resultant degree of pelvic stability for application to gross human skeletal remains. The modified Tile criteria were applied to the skeletal remains of 22 individuals from the Cleveland Museum of Natural History and Universidad Nacional Autónoma de México that displayed evidence of pelvic injury. Because these categories are tied directly to clinical assessments concerning the severity and treatment of injuries, this approach can aid in the identification of manner and cause of death, as well as interpretations of possible mechanisms of injury, such as those typical in car-to-pedestrian and motor vehicle accidents.