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.     

Patterns of Trauma Induced by Motorboat and Ferry Propellers as Illustrated by Three Known Cases from Rhode Island*

Abstract: Understanding patterns of trauma is important to determining cause and manner of death. A thorough evaluation of taphonomy, trauma, and bone fracture mechanisms is necessary to reconstruct the circumstances of the death. This study examines the skeletal trauma caused by boat propeller strikes in terms of wound characteristics and location based on three cases from Rhode Island. These case studies review the traumatic characteristics caused by propeller injuries and highlight the anatomic regions most likely to sustain skeletal trauma. With this information, investigators may be able to identify propeller trauma even in severely decomposed remains. The discussion of boat propeller trauma also raises issues regarding how forensic anthropologists and forensic pathologists classify trauma (specifically blunt force vs. sharp) and highlights semantic issues arising in trauma classification. The study also discusses why these propeller cases should be classified as blunt trauma rather than sharp or chop/hack trauma. Ultimately, the authors urge consistency and communication between pathologist and forensic anthropologists performing trauma analyses.     

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.     

Scanning Electron Microscope Analysis of Gunshot Defects to Bone: An Underutilized Source of Information on Ballistic Trauma

Recent years have seen increasing involvement by forensic anthropologists in the interpretation of skeletal trauma. With regard to ballistic injuries, there is now a large literature detailing gross features of such trauma; however, less attention has been given to microscopic characteristics. This article presents analysis of experimentally induced gunshot trauma in animal bone (Bos taurus scapulae) using full metal jacket (FMJ), soft point (SP), and captive bolt projectiles. The results were examined using scanning electron microscopy (SEM). Additional analysis was conducted on a purported parietal gunshot lesion in a human cranial specimen. A range of features was observed in these samples suggesting that fibrolamellar bone response to projectile impact is analogous to that observed in synthetic composite laminates. The results indicate that direction of bullet travel can be discerned microscopically even when it is ambiguous on gross examination. It was also possible to distinguish SP from FMJ lesions. SEM analysis is therefore recommended as a previously underexploited tool in the analysis of ballistic trauma.     

Understanding rib fracture patterns: incomplete and buckle fractures

Reconstructing traumatic thoracic events, especially when soft tissues are absent, requires an advanced understanding of ribcage fracture patterns. The morphology and orientation of ribs complicate the fracture pattern, as a single blow often causes multiple fractures at various locations. Furthermore, fracture types observed in ribs are not explained easily by current bone biomechanic literature. Using evidential skeletal material archived at the Regional Forensic Center, Memphis, the ribs of 43 blunt force trauma cases were analyzed. A total of 195 incomplete fractures and 63 buckle fractures were noted. Incomplete fractures, previously thought to be common in children but rare in adults, were found among individuals ranging in age from 21-76 years. A buckle fracture, failure resulting from compressive instability, has been undefined previously in bone trauma literature but was repeatedly observed in this sample. This study elucidates recognizable rib fracture patterns while emphasizing gross bone examination for force and mechanical factors.     

Differentiation of traumatic and heat-induced dental tissue fractures via SEM analysis

Previous studies have examined the effects of heating on teeth; however, none have identified characteristics that allow analysts to differentiate traumatic from heat-induced fractures. This study examined our ability to discern notable differences in preincineration traumatic fractures and heat-induced fractures in postincineration dentition. Twelve anterior dental specimens were subjected to blunt force trauma while a second set were not. All 24 samples were then incinerated in a muffle furnace at a peak temperature (900°C) consistent with house fires. The specimens were subsequently examined with a scanning electron microscope to identify and compare heat-induced and traumatic fractures. The results obtained during examination yielded no differences between the features displayed by specimens that had been inflicted with preincineration trauma and those that did not. Unlike bone, distinguishing features for the differentiation of traumatic and heat-induced fractures could not be compiled.     

Microscopic Pattern of Bone Fractures as an Indicator of Blast Trauma: A Pilot Study

The assessment of fractures is a key issue in forensic anthropology; however, very few studies deal with the features of fractures due to explosion in comparison with other traumatic injuries. This study focuses on fractures resulting from blast trauma and two types of blunt force trauma (manual compression and running over), applied to corpses of pigs; 163 osteons were examined within forty fractures by the transmission light microscopy. Blast lesions showed a higher percentage of fracture lines through the Haversian canal, whereas in other types of trauma, the fractures went across the inner lamellae. Significant differences between samples hit by blast energy and those runover or manually compressed were observed (p < 0.05). The frequency of pattern A is significantly higher in exploded bones than in runover and compressed. Microscopic analysis of the fracture line may provide information about the type of trauma, especially for what concerns blast trauma.     

Death caused by a signal rocket--not an isolated case*

Fatalities related to sporting events are predominantly caused by blunt force injuries especially due to the emotional involvement of crowd, but occasionally other types of trauma are reported as well. A case of very rare trauma caused by shooting with a hand-held parachute signal rocket during a football match is presented. A 17-year-old football fan sustained fatal injuries, a combination of mechanical trauma caused by rocket penetration, as well as extensive thermal burning of the thoracic viscera. Analysis of the event was based on autopsy findings and evidence produced by medicolegal and ballistic experts. Improper use of a hand-held signal rocket, designed for marine distress signals, may cause serious injuries either mechanically, due to explosion, or as a result of thermal discharge. In the reported case, pattern of injuries is discussed, and medical finding corroborated to other available evidence. The presented case is a reminder that the forensic pathologist should be informed accordingly on the type and features of weapon suspected to produce injury, to be able to understand traumatic changes, and look for potential presence of foreign bodies at postmortem examination.     

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。     

Primary and secondary skeletal blast trauma

This study examines primary (resulting from blast wave) and secondary (resulting from disintegrated, penetrating fragments) blast trauma to the skeleton. Eleven pigs were exposed to semi-controlled blast events of varying explosive type, charge size, and distance, including some cases with shrapnel. Skeletal trauma was found to be extensive, presenting as complex, comminuted fractures with numerous small, displaced bone splinters and fragments. Traumatic amputation of the limbs and cranium was also observed. Fractures were concentrated in areas nearer the blast, but there was generally no identifiable point of impact. Fractures were more random in appearance and widespread than those typically associated with gunshot or blunt force injury events. These patterns appear to be uniquely associated with blast trauma and may therefore assist forensic anthropologists and other forensic examiners in the interpretation of skeletal trauma by enabling them to differentiate between blast trauma and trauma resulting from some other cause.     

Shark‐Inflicted Trauma: A Case Study of Unidentified Remains Recovered from the Gulf of Mexico*

Abstract: Here, we present a case of an unidentified male whose remains, except for the right arm, were recovered from the Gulf of Mexico 10 years prior to osteological analysis by forensic anthropologists. After the poorly preserved soft tissue was removed and the bones cleaned, forensic analysis revealed an unusual series of hard tissue trauma later attributed by a shark expert as shark scavenging and/or predation. Identified were five unique hard tissue trauma patterns that are bite mark artifacts produced by sharks: punctures without fractures, punctures with associated fractures, striations with bone shaving, overlapping striations, and incised bone gouges. The cooperation among experts provided a comprehensive death case analysis and a better understanding of shark‐inflicted trauma on human skeletal remains.     

Analysis of blunt trauma injuries: vertical deceleration versus horizontal deceleration injuries

There are several similarities found in blunt trauma injuries to humans sustained as a result of vertical deceleration (falling) and those sustained as a result of deceleration in a horizontal plane (automobile accidents). However, examination of the patterns of traumatic skeletal injuries can distinguish those injuries associated with falling from heights from those associated with automobile accidents. While there is considerable variation within each type of blunt trauma injury dependent on the angle at which one falls or is struck, there are several characteristic skeletal features associated with each type of trauma. In this study we review both the current literature and human skeletal remains from the University of New Mexico's Documented Collection known to have been subjected to blunt trauma. This collection is used to characterize and differentiate the pattern of skeletal injuries to various parts of the body for each type of trauma. These assessments are applied to investigate the traumatic skeletal lesions observed in a forensic case where the manner of death is unknown. Analyses suggest two possible scenarios that would explain the death of the individual investigated, with death most likely related to a vehicular-pedestrian accident.     

An unusual blunt force trauma pattern and mechanism to the cranial vault: Investigation of an atypical infant homicide

This case report presents an unusual fracture pattern in the cranium of a four-month-old infant indicative of child abuse. Upon postmortem examination, the infant presented with numerous bilateral linear cranial fractures running perpendicular to the sagittal suture with depressed and curvilinear fractures apparent on the supra-auricular surfaces of the cranium. Histological evidence indicates multiple traumatic events to the cranium. In addition, the stair-step pattern of a parietal fracture may represent multiple contiguous fractures from repeated loading of the head at different times with variation of the focal points of compressive force. Additionally, the left humerus, left radius, and left ulna have healing metaphyseal fractures, and the left ulna also has an antemortem diaphyseal fracture which resulted in the distal metaphysis being rotated 45 degrees medially. Integration of autopsy, anthropological, and neuropathological reports for this case suggest multiple inflicted injury episodes with a repeated atypical mechanism(s) to the cranial vault of the infant. During investigative interviews, the caretaker admitted to squeezing the infant's head and neck on multiple occasions to quiet the child. This reported abusive mechanism is consistent with the pattern of symmetric cranial fractures and soft tissue injuries indicating asphyxiation. This case report provides forensic investigators with a potential trauma mechanism to explore in cases when a similar pattern of cranial trauma is observed and highlights the need for greater research on fracture propagation and fracture healing in the infant cranium.     

Nonfracture-associated fatal fat embolism in a case of child abuse

Fatal fat embolism is usually thought of as a sequel to long-bone fracture, although cases secondary to soft tissue injury and atraumatic conditions have been infrequently reported. In this case of a two-year-old child-abuse victim who sustained multiple blunt traumatic injuries without skeletal fractures, pulmonary and systemic (brain and kidney) fat emboli were identified. At autopsy, all thoracic and abdominal viscera were intact; cranial contents exhibited only diffuse symmetrical petechial hemorrhages of the white matter. Because of the severe and widespread nature of soft tissue hemorrhage, and the absence of a grossly discernible cause of death, fat embolism was suspected. Using a combination of frozen section with oil red O staining and formalin-fixed osmium stained tissues, the immediate cause of death was determined to be diffuse fat embolism. Review of the literature reveals a pathophysiologic basis for fat embolism in the absence of fracture, both as a consequence of an acute increase in local pressure at the site of trauma and an alteration of the emulsification of blood lipids during shock. In light of these findings, we present this case to remind the forensic science community to consider fat embolism as the cause of death in cases of blunt-force injury without fracture.     

Examination of misconceptions surrounding fatal fire victims

Fire deaths are not unusual in forensic investigative practice but due to the destructive nature of fire they are often very difficult to investigate. With the need to identify the deceased and the events surrounding the manner and cause of death, knowledge of thermally induced alteration to the human body is important. Within the fire investigation community, a number of misconceptions have been present for years regarding the protrusion of the tongue as an indicator of life during the fire, and fractured skulls as the result of brains boiling and skulls exploding. This work presents qualitative analysis on the experimental burning of 42 unembalmed human donated cadavers by the San Luis Obispo Strike Team (SLOFIST) on their annual Forensic Fire Death Investigation Course (FFDIC) between 2017 and 2019. Prior to burning, the position of the tongue within the dental arch was confirmed and sharp, blunt, surgical and gunshot trauma to the cranium documented. Temperature was recorded from ignition through to suppression with thermocouples present both within the scene and the body. Post burn analysis on the position of the tongue, observation of cranial fractures and presence of brain tissue were recorded and analysed in conjunction with thermocouple data, fire scene dynamics and body demographics. The results provide a more comprehensive understanding of the thermal environmental factors involved in producing the phenomena that facilitate these misconceptions, identifying that a more thorough understanding of individual fire scenes and their development is essential when interpreting alteration and injury to the body of the fatal fire victim.     

Injuries of the Head from Backface Deformation of Ballistic Protective Helmets Under Ballistic Impact

Modern ballistic helmets defeat penetrating bullets by energy transfer from the projectile to the helmet, producing helmet deformation. This deformation may cause severe injuries without completely perforating the helmet, termed “behind armor blunt trauma” (BABT). As helmets become lighter, the likelihood of larger helmet backface deformation under ballistic impact increases. To characterize the potential for BABT, seven postmortem human head/neck specimens wearing a ballistic protective helmet were exposed to nonperforating impact, using a 9 mm, full metal jacket, 124 grain bullet with velocities of 400–460 m/s. An increasing trend of injury severity was observed, ranging from simple linear fractures to combinations of linear and depressed fractures. Overall, the ability to identify skull fractures resulting from BABT can be used in forensic investigations. Our results demonstrate a high risk of skull fracture due to BABT and necessitate the prevention of BABT as a design factor in future generations of protective gear.     

Blunt force cranial trauma in the Cambodian killing fields

In this paper we present a unique pattern of blunt force cranial trauma that was observed in 10 of a sample of 85 crania from a Cambodian skeletal collection comprised of Khmer Rouge victims. Initial examination of the trauma, which presents as substantial damage to the occipital with fractures extending to the cranial base, suggested the pattern was classifiable as a basilar or ring fracture. However, further investigation, including trauma analysis and historical research, revealed that this fracture type is distinctive from basilar and ring fractures. Historical data indicate that a particular execution method was the likely source of the trauma. Recognition of this trauma pattern is significant because it exemplifies the distinct fracture configuration resulting from an apparently categorical and methodical execution technique. Identification of this fracture type could potentially assist forensic investigators in the recognition of specific methods of murder or execution.     

Punched with a fist: the etiology of a fatal depressed cranial fracture

We report a case in which a 33-year-old man was discovered unconscious following a fistfight with another man. Emergency neurosurgical efforts to repair a depressed temporoparietal skull fracture and associated brain injuries were unsuccessful. The forensic anthropologist and pathologist worked in tandem to sort out a complex combination of cranial evidence, including healed antemortem trauma, perimortem blunt force trauma, remote and recent neurosurgical intervention, and the craniotomy cut performed at autopsy. The victim had suffered head injuries and a right temporoparietal craniotomy ten years prior to death. The perimortem cranial fractures were centrally located within a surgically repaired roundel of bone involving portions of the right temporal and parietal bones. Reportedly, the victim was punched on the right side of his head as he was lying on the ground with the left side of his head against an asphalt surface. A primary question in the case was whether a blow with a fist could have produced the observed cranial injuries. To adequately answer that question, known data on the minimum amount of force required to fracture the temporoparietal region were compared to data on the amount of force generated by a blow with a fist. A biomechanics expert demonstrated that a single blow with a fist to the rigidly supported head of the victim could generate the required force to produce the observed fractures. The previous medical condition possibly predisposed the victim to the cranial fractures and contributed to the depressed nature of the fractures. Although depressed cranial fractures do not typically result from a blow with a fist, it was determined in this case that the fracture pattern was consistent with a punch to the head.     

Identifying chop marks on cremated bone: a preliminary study

The purpose of this analysis is to evaluate the effects of burning on hacking trauma inflicted with a cleaver and to assess the diagnostic potential of cleaver marks exposed to fire. Thirty pig forelimbs (radius and ulna) and 30 beef ribs were each subjected to five blows with a cleaver and five cuts with a knife prior to burning in an outdoor fire. Bones were deliberately agitated to ensure maximum cremation and induce fragmentation. Results indicate that hacking weakens bone, making fire-induced fragmentation more likely at the sites of trauma. Chop marks were easily identified on burned bone, their characteristics largely unaffected by cremation.     

Blast Injury and the Human Skeleton: An Important Emerging Aspect of Conflict‐Related Trauma

Recent decades have seen an accelerating trend in warfare whereby a growing proportion of conflict‐related deaths have been caused by explosions. Analysis of blast injury features little in anthropological literature. We present a review of clinical literature that includes prevalence of injury to anatomical regions and potential indicators of blast injury which can be used by forensic anthropologists. This includes high prevalence of extremity (22.8–91.2%) and facial (19.6–40%) injury in combat contexts, lower limb fractures (19–74.3%) in suicide bombing, traumatic amputation (3–43%) and diffuse fracture patterns in terrorist bombings. Potential indicators of blast trauma include blowout fractures in sinus cavities from blast overpressure, transverse mandibular fractures, and visceral surface rib fractures. Ability to recognize blast trauma and distinguish it in the skeleton is of importance in investigations and judicial proceedings relating to war crimes, terrorism, and human rights violations and likely to become increasingly crucial to forensic anthropology knowledge.