Mechano- and morphogenesis of gunshot fractures in the flat bones

Gunshot fractures in flat bones, bullet defects in the continuum were studied in experiment. The laws of gunshot fracture formation were formulated. In far distance, bullet has a direct and radial blow action. The direct blow induces comminution and disintegration of the bone tissue with dislocation of bone fragments; radial blow potentiates bone destruction. Morphological characteristics of gunshot fractures of flat bones depend on the force of the direct and radial impact action and can be used for estimation of the far shot distance, kinetic energy and shape of the head of the shell.     

毛发枪弹损伤的环境扫描电镜研究

目的探讨毛发枪弹损伤微观形态与射击距离之间的关系。方法应用环境扫描电镜/能谱仪对64式手枪在0~200cm范围内射击造成的毛发损伤及附着物进行形态和成分分析。结果0~30cm射击,毛发表面粘附有大量密集分布的球形射击残留物颗粒,鳞片有严重斑纹状损伤和崩裂缺损;30~60cm射击,毛发表面粘附有较多散在分布的球形射击残留物颗粒,鳞片有轻微斑纹状损伤和崩裂缺损;100cm距离射击,毛发表面粘附有少数个别射击残留物颗粒,鳞片无斑纹状损伤;200cm距离射击,毛发表面无射击残留物。毛发枪弹射击断裂形态差异较大,大体分为剪切断裂和牵拉断裂两种类型,与射击距离无明显相关性。结论毛发表面粘附的大量球形射击残留物颗粒及其造成的鳞片斑纹状损伤对于法医学鉴定贴近距离射击((30cm)具有重要的实用价值。     

A Biomechanical Evaluation of Skull–Brain Surrogates to Blunt High‐Rate Impacts to Postmortem Human Subjects

The field of forensic injury biomechanics is an emerging field. Biomechanically validated tools may assist interdisciplinary teams of investigators in assessing mechanisms of blunt head trauma resulting in skull fractures. The objective of this study is to assess the biofidelity of spherical, frangible skull–brain (SB) surrogates. Blunt impacts were conducted at 20 m/s, using an instrumented 103 g rigid impactor, to the temporo‐parietal region of four defleshed cephalic postmortem human subjects (PMHS). Force–deformation response, fracture tolerance, and fracture patterns were recorded for comparison to spherical skull–brain surrogates. Three brain substitutes were assessed: 10% gelatin, lead shot with Styrofoam and water. Force–deformation response of the skull–brain surrogates was similar to defleshed PMHS up to the point of fracture; however, none of the surrogates fractured at tolerance levels comparable to the PMHS. Fracture patterns of the skull–brain surrogates were linear and radiating, while PMHS fractures were all depressed, comminuted.     

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。     

Histomorphology of healing of fractures, splits, and defects in the cranial bones

The histomorphology of healing of fractures in the calvarial bones were studied: 39 autopsies and 61 bioptic samples were investigated within the time span ranging from 1 to 5 years; as well as 32 experiments with dogs were made. A tight contact between fracture edges is the key condition for fracture healing (of the mentioned bones) through central callus. Should there be no such contact, the fracture edges were joined by fibrous tissue, which lacks any osseous structures. The periosteum of the internal bone lamella and the adjoining dura mater of brain are the main sources for bone regeneration in the calvarium.     

舌骨假阳性骨折12例分析

目的 探讨舌骨假阳性骨折形成的原因以及法医学鉴定要点. 方法 整理12例在实际检案中舌骨假阳性骨折案例资料并分析其形成原因. 结果 舌骨假阳性骨折主要是由于检验时人为操作（4例）以及先天性分离型舌骨（8例）误判所致. 结论 通过骨折周缘肌肉、软组织出血以及骨折断端检验,可以对人为操作因素致舌骨骨折、分离型舌骨等舌骨假阳性骨折与真性骨折进行区分.     

Fatal neck injuries caused by blank cartridges.

We report three cases where fatal neck injuries were caused by blanks from starting pistols. The weapons were loaded with blank cartridges or tear gas cartridges. Neither live ammunition nor any form of projectile was used. All three cases involved a contact discharge. The gas pressure caused by firing the weapons created extensive wound cavities in all three cases. Each victim died from blood loss as a result of ruptured cervical vessels; there were no air embolisms. In one case, a man shot himself eight times with two different starting pistols, and the wounds could be matched to each gun by the muzzle imprint marks on the neck.     

有限元法研究高坠中躯干不同部位着地的肋骨骨折机制

目的利用有限元法研究躯干不同部位着地的肋骨损伤机制,对重建高坠过程提供新技术与新方法。方法采用有限元法观察全人类安全模型THUMS4.0在躯干部不同部位着地时的肋骨损伤情况,并与实际案例进行比较,从生物力学角度分析高坠导致的肋骨骨折形成机制。结果不同部位着地所形成的应力、应变分布及肋骨骨折部位存在一定差异。躯干前侧着地时双侧均发生肋骨骨折,骨折主要位于肋骨-肋软骨交界处和腋中线区域;躯干右前侧着地时,着地一侧首先发生肋骨骨折,骨折分布于右侧腋中线至腋后线区域以及双侧肋骨-肋软骨交界处;躯干后侧着地时,骨折主要位于双侧肋骨后侧;躯干右后侧着地时,着地部位易发生多发性肋骨骨折。塑性应变多集中于骨折处,von Mises应力除集中于骨折处,也可位于其他部位。结论躯干部不同部位着地时,肋骨骨折部位及损伤机制具有一定差异。     

Healed fractures of the larynx and lingual bone in forensic autopsy]

Laryngohyoid fractures are a frequently investigated matter, especially in the forensic literature. On the other hand, there are only very few (old) forensic reports of such fractures in survived cases. However, healed fractures are not seldom found in forensic autopsies: In a personal series of 1160 forensic autopsies (adult persons) a careful dissection of the laryngohyoid complex was done by 1 investigator. Only a macroscopic examination of the cartilages was carried out; radiographs and histological slices were not regularly made. Therefore only a part of existing old fractures is detectable; for example, healed fissures are not visible with this simple method. Furthermore, asymmetries of the thyroid laminae cannot be declared as posttraumatic without additional examination, because this condition is described as possible anatomic anomaly. From that, the injury frequencies presented here only mark the lower threshold of the existence of such findings. Healed fractures of the upper thyroid horns and the major hyoid horns can be easily detected even in a routine examination, if healing resulted in a fixed dislocation or apposition of bone surrounding the former fracture site. In the present series, this was the predominant localization of old fractures: the upper thyroid horns (43 cases), followed by the hyoid cornua (12 cases), a combination of both sites (5) and cricoid fractures (5). Of the total 65 healed fractures (5.6%), 35 were found in the group of 290 chronic alcoholics (12.1%) and only 3.4% in non-alcoholics. In the subgroup of middle-aged alcoholics, the fracture rate increased up to 19%. However, this group did not present a higher rate of fresh laryngohyoid injuries (not related to strangulation) than the other cases. The old fractures probably resulted from minor "daily" injuries (like falls), which are common, especially in chronic alcoholics. The frequency of such findings should be in mind if an apparently fresh fracture, found in an actual autopsy, should be related to the cause of death: there is a real chance, that this fracture occurred prior, and without causal connection to the factors resulting in death. Therefore a histological examination of the age of this finding is necessary. Cricoid fractures are quite uncommon, except in serious external neck trauma. In 1 of our 5 cases, this fracture was caused by repeated cruelty, finally resulting in death.     

Persistence of Biological Traces at Inside Parts of a Firearm from a Case of Multiple Familial Homicide

Backspatter from wounds caused by contact shots against a biological target had before been shown to be propelled into firearms' barrels where they can persist and be retrieved from as relevant forensic evidence. Herein, that insight was applied to the investigation of a case of multiple familial homicide with a firearm. Samples of backspatter were collected from the firearm using DNA‐free swabs. DNA was extracted from the swabs, and 16 STR systems were PCR‐amplified to generate DNA profiles of all victims shot by the firearm. The quality of the resulting DNA profiles was sufficient to exclude the perpetrator as donor and to differentiate the three closely related victims thereby proving that all three victims had been shot by the same firearm from very close or contact distance. A key insight gained from this case was that not only a firearms' barrel inside but other inner surfaces may be charged with profilable DNA.     

The Role of Interface on the Impact Characteristics and Cranial Fracture Patterns Using the Immature Porcine Head Model

The role of impact interface characteristics on the biomechanics and patterns of cranial fracture has not been investigated in detail, and especially for the pediatric head. In this study, infant porcine skulls aged 2–19 days were dropped with an energy to cause fracturing onto four surfaces varying in stiffness from a rigid plate to one covered with plush carpeting. Results showed that heads dropped onto the rigid surface produced more extensive cranial fracturing than onto carpeted surfaces. Contact forces generated at fracture initiation and the overall maximum contact forces were generally lower for the rigid than carpeted impacts. While the degree of cranial fracturing from impacts onto the heavy carpeted surface was comparable to that of lower‐energy rigid surface impacts, there were fewer diastatic fractures. This suggests that characteristics of the cranial fracture patterns may be used to differentiate energy level from impact interface in pediatric forensic cases.     

Fracture patterns on the infant porcine skull following severe blunt impact

The objective of this study was to document patterns of fracture on infant porcine skulls aged 2-28 days (n = 57) because of a single, high energy blunt impact to the parietal bone with rigid (nondeformable) and compliant (deformable) interfaces. Fracture patterns were mapped using Geographic Information System software. For the same generated impact force, the rigid interface produced more fractures than the compliant interface for all ages. This study also showed that this increased level of impact energy versus an earlier study using a lower energy resulted in new sites of fracture initiation and also caused previously defined fractures that propagate into an adjacent bone. Several unique characteristics of bone and diastatic fracture were documented as a function of specimen age, impact energy, and interface. These data describe some baseline characteristics of skull fracture using an animal model that may help guide future studies from forensic case files.     

Fractures of the arches of the atlas: a study of their causation

The autopsy findings in 32 accidental deaths which showed fracture(s) of the arches of the atlas have been correlated to reconstructions of the course of events in the accidents. Flexion of the head causing fracture(s) of the neural arch or odontoid process of the axis also resulted in fracture(s) of the posterior arch due to downward traction. Extension of the head causing fracture of the odontoid process of the axis gave rise to fractures of the posterior arch due to pressure from below. Tilting of the head caused marginal fractures of the anterior arch due to oblique traction. Tilting of the head also caused fracture(s) of the anterior and/or posterior arch due to transverse extension of the atlas ring and/or superior dislocation of one lateral mass in relation to the other. Oblique flexion or extension of the head resulted in similar fractures. Flexion of the head with some rotation combined with compression of the neck can cause the anterior margin of one upper joint surface of the axis to act as a wedge separating the anterior arch of the atlas from below. Extension of the head with some rotation combined with compression of the neck can lead to a fracture running through one lateral mass due to its tilting-dislocation in posterior direction. It is striking that there was no fracture of the atlas which could be ascribed to a simple and symmetric compression of the neck (classical Jefferson's fracture).     

Frequency of blood spatters on the shooting hand and of conjunctival petechiae following suicidal gunshots wounds to the head

A total of 103 suicidal and 29 homicidal gunshot fatalities were evaluated. In 42% of the suicides, characteristic findings like blood spatters and/or powder soilings, could be found on the shooting hand by naked-eye inspection indicating the importance of an accurate examination of the deceased's hands at autopsy for a preliminary diagnosis. Petechial hemorrhages of the conjunctivae due to the gas pressure after discharge of the weapon were observed in 22% of those cases with contact shot wounds to the head/neck, but not in cases of distant shot injuries following the use of non-high velocity ammunition. Therefore, conjunctival petechiae can be regarded as an additional but optional sign of contact head shots in cases without alterations possibly influencing the development of conjunctival pin-point bleedings. The evidence of such findings can be of practical importance if the entrance shot wound cannot be examined for whatever reason.     

The occurrence of cervical fractures in victims of judicial hanging.

Cervical vertebrae from 34 victims of judicial hanging were examined. In only six cases was there a fracture of the axis and only one other fracture was seen in the series. The fractures were of two types. Three were the traditional 'Hangman's fracture' whilst three were of a type previously unreported. The incidence of fracture was unassociated with drop, date age or hangman. The results of the post mortems on these subjects were reviewed and found to be grossly inaccurate with regard to fractures. The results indicate that the traditional hangman's fracture occurred in only a small proportion of cases of judicial hanging. The cause of fractures and cause of death in judicial hanging are discussed with a brief history of judicial hanging in this country.     

Ring fractures of the base of the skull

Besides complete ring fracture, also incomplete fractures open to the front, back, or side(s) are discussed on the basis of 61 ring fractures of the base of the skull. The fractures were found in casualties from traffic accidents (car passengers, cyclists and motorcyclists, pedestrians), after falls and other accidents. In traffic accidents, compression, traction, hyperextension, extreme lateral movements, and torsional forces can lead to ring fractures. In falls, compression and traction are the main forces. A fall in one plane is also capable of producing an incomplete ring fracture. Incomplete ring fractures may show lateral emphasis. The greater fracture length is found on the impact side (e.g., in falls). In contrast to complete ring fractures, incomplete ring fractures are compatible with longer survival times. Ring fractures are to be classified under direct fractures. This does not exclude the possibility that overall deformations of the skull with bursts can partly determine the course of the fracture.     

Expert evaluation of the gunshot distance based on the volume of wound canal in flat bones

Different-distance experimental shots were made from a rifled gun at flat bones. Those shot distances were established, at which the wound canal had the smallest volume, and, at which entry and exit holes were virtually identical and matched the bullet diameter. A bigger shot distance was associated with an increasing volume of the wound canal caused by a bigger exit hole. A smaller shot distance led, also, to an increasing volume of the wound canal caused by bigger entry and exit holes. The volume of the wound canal in flat bones can be used as a reliable criterion in assessing the shot distance.     

Classification of Porcine Cranial Fracture Patterns Using a Fracture Printing Interface,,

Distinguishing between accidental and abusive head trauma in children can be difficult, as there is a lack of baseline data for pediatric cranial fracture patterns. A porcine head model has recently been developed and utilized in a series of studies to investigate the effects of impact energy level, surface type, and constraint condition on cranial fracture patterns. In the current study, an automated pattern recognition method, or a fracture printing interface (FPI), was developed to classify cranial fracture patterns that were associated with different impact scenarios documented in previous experiments. The FPI accurately predicted the energy level when the impact surface type was rigid. Additionally, the FPI was exceedingly successful in determining fractures caused by skulls being dropped with a high‐level energy (97% accuracy). The FPI, currently developed on the porcine data, may in the future be transformed to the task of cranial fracture pattern classification for human infant skulls.     

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。     

Injuries and fatalities caused by gas-/warning weapons

Detailed report of 5 cases of violation with gas or warning firearms, 3 of them lethal. In one case a modified weapon (elongated barrel) and steel bullets were used, resulting in shot of the head with retained missile and lethal bleeding. In the other cases, regular weapons (8 or 9 mm cartridges) were used for contact shots; violation occurred only by the effect of powder gases. One of these cases was a suizide (lethal temporal gunshot), in the other cases shots by another person: a) shot against the arm with large soft-tissue damage (survived); b) and c) shot against the neck with exceeding rupture of the soft tissues, minimal damage of the neck arteries and in one cases bilateral tears of the hypopharynx. In this case a delayed death after primarily well operated injury occurred after 12 days by bleeding into the airways from ruptured external carotid artery.