Discrimination of Falls and Blows in Blunt Head Trauma: Assessment of Predictability Through Combined Criteria*

Abstract: The discrimination of falls from homicidal blows in blunt head injuries is a common but difficult problem in both forensic anthropology and pathology. Three criteria have been previously proposed for this distinction: the hat brim line rule, side lateralization of fractures, and number of lacerations. The aim of the present study was to achieve a better distinction rate by combining those criteria and assess the predictability of these combined criteria tools. Over a 6‐year period, a total of 114 cases (92 males and 22 females) were studied: 21 cases of downstairs falls, 29 cases of falls from one’s own height, and 64 cases of head trauma by a blunt weapon. The results revealed predictability rates varying from 62.5 to 83.3% for criteria pointing towards a fall. As for combined criteria in favor of a blow, the assumption was accurate in all cases (100%).     

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.     

The Frequency of Cranial Base Fractures in Lethal Head Trauma

The interpretation of cranial base injuries has never been investigated from a purely anthropological perspective. Very little exists in forensic literature in order to interpret the significance of cranial base fractures. We analyzed 296 cases of deaths due to skull–brain injuries. The frequency of vault fractures was 75.7% and that of base fractures was 91.9%. We observed the distribution of cases of death according to manner of death and manner of injury and number of fossae involved. These observations were analytically compared to different variables (age, sex, manner of injury, and mode of injury). The study presented the proportion of base fractures associated with vault fractures, and the frequency of absence of base fracture in subjects with no vault fractures. Interesting associations of base fractures to age and manner of death are shown.     

Discrimination of falls and blows in blunt head trauma: systematic study of the hat brim line rule in relation to skull fractures

In the discrimination of falls from blows in blunt head trauma, the hat brim line rule is one of the most often used criteria. The present study assesses the validity of the hat brim line rule for skull fractures and looks at other possible criteria. All autopsy cases were retrospectively analyzed on a 5-year period. Cases selected consisted of downstairs falls (n = 13), falls from one's own height (n = 23), and homicidal blows (n = 44). Results show that fractures above the hat brim line are more in favor of blows, while fractures in the hat brim line zone are more difficult to distinguish. The majority of fractures were located on the left side for homicidal blows and on the right side for falls. A higher average number of lacerations was revealed for homicidal blows. In conclusion, this study establishes three criteria in favor of blows: (i) localization of a wound above the hat brim line; (ii) left side lateralization; and (iii) a high number of lacerations.     

Interpreting Injury Mechanisms of Blunt Force Trauma from Butterfly Fracture Formation

According to biomechanics of fracture production during blunt impact, tubular bones are subject to compressive (impact site) and tensile (opposite impact site) forces; this causes bones to break in tension before compression, producing Y-shaped fracture patterns with breakaway (butterfly) fragments. In current forensic models, the side of the bone exhibiting the breakaway fragment is designated the impact side, with initial breakage occurring opposite. Fracture production and patterning of blunt impacts to 255 sheep femora were analyzed. Contra the existing model, only 60% of complete butterfly fractures exhibited impact side breakaway fragments. Although fractures initiated on the tension, nonimpact side, butterfly fragments formed on either compression or tension sides. Using newly defined breakaway fragment shape criteria, impact side was estimated with 98% accuracy for both complete and partial butterfly fractures. Furthermore, the results suggest that the impact site is the located on one of the Y-fracture's arms, not the butterfly fragment's center, as previously modeled.     

Examination of Hacking and Blunt Force Skeletal Trauma

Hacking trauma is prevalent in forensic cases involving genocide and dismemberment, but research into the identification of this type of trauma is lacking. The present study examines characteristics of hacking and blunt force skeletal trauma in order to determine if there is a point at which blunt force trauma becomes distinguishable from hacking trauma. Ten implements with a range of blade angles (i.e., the striking surface of the implement) were used in conjunction with a controlled-force hacking device to impact 100 limb bones of white-tailed deer (Odocoileus virginianus). Observations of the trauma included the occurrence and degree of fragmentation, the entrance widths of the impacts, and composite scores of six hacking characteristics, especially the distinctive V-shaped kerf. ANOVA tests and regression analyses were used to assess the relationships between these characteristics and the blade angles. A significant relationship (p-value = 0.011) was found between the composite hacking scores and the blade angles, indicating that blunt force and hacking trauma can be distinguished. The entrance widths of the impacts exhibited a significant relationship with the blade angles (p-value = 0.037). There was also a significant relationship between the visibility of a V-shaped kerf in the bones (p-value = 0.003), with visibility decreasing around the 60° blade angle. These data should assist in establishing guidelines to differentiate hacking and blunt force skeletal trauma in cases where the implement is on a spectrum between sharp and blunt.     

The Forensic Implications of Amphetamine Intoxication in Cases of Inflicted Blunt Craniocerebral Trauma

The effects of D‐amphetamine on outcome after blunt craniocerebral trauma are characterized and the potential legal implications discussed. Traumatic brain injury (TBI) was induced under general anesthesia in adult, male Sprague Dawley rats using the impact acceleration model. At 10 min prior to injury, D‐amphetamine (5 mg/kg) or saline vehicle was administered subcutaneously; animals were subsequently assessed over a 7‐day period post‐trauma for motor outcome using a rotarod device. D‐amphetamine treated animals performed significantly better (p < 0.001; ANOVA) than vehicle treated controls on their motor assessment, suggesting that D‐amphetamine exposure prior to injury either is neuroprotective or enhances motor performance. It is possible, therefore, that an individual who has taken amphetamines may function at a better motor level after head trauma than one who has not been exposed to the drug. Future interpretations of the potential effects of amphetamines on TBI should include this possibility.     

The Accuracy and Applicability of 3D Modeling and Printing Blunt Force Cranial Injuries

The purpose of this study was to determine the factors affecting the accuracy of 3D models and 3D prints of cranial blunt force trauma, to evaluate the applicability and limitations of modeling such injuries. Three types of cranial blunt force lesions were documented (hinge, depressed, and comminuted) using three forms of surface scanning (laser, structured light scanner, and photogrammetry) at two different quality settings (standard and high). 3D printed models of the lesions were produced using two different materials (a gypsum‐like composite powder called VisiJet^® PXL and an acrylic engineered composite plastic called VisiJet^® M3 in crystal colour). The results of these analyzes indicate the prints in this study exhibit some statistically significant differences from the actual bone lesions, but details of the lesions can be reproduced to within 2 mm accuracy.     

Cardiac Injuries Caused by Blunt Trauma: An Autopsy Based Assessment of the Injury Pattern

Abstract:  Nonpenetrating chest trauma with injury to the heart and aorta has become increasingly common, particularly as a result of rapid deceleration in high-speed vehicular accidents, over the past 2–3 decades. The high mortality rate of cardiac injuries and possible late onset complications make blunt cardiac injuries an important challenging point for legal medicine. One hundred and ninety cases with blunt cardiac injuries in a period of 3 years were analyzed retrospectively in terms of patterns of cardiac injury, survival times, and demographic profiles of the cases in this study.     

Comparing Known and Reconstructed Circumstances of Death Involving a Blunt Force Trauma Mechanism through a Retrospective Analysis of 21 Skeletonized Individuals

Little is known about to what extent the events surrounding death can be reliably reconstructed from blunt force trauma analysis alone. In this study, we reconstruct circumstances of death from a blind blunt force trauma analysis using a sample of 21 individuals of known death circumstances, obtained from two identified skeletal collections in Portugal. Fresh versus dry bone trauma and probable mechanism of fracture production were identified. The overall pattern of injuries was then used to reconstruct the most likely circumstances of death. Results show an agreement between the proposed and the reported circumstances for 13 individuals (68.4%), disagreement for 3 (15.8%), and similarity in 3 cases (15.8%). Although the significant amount of agreement highlights the potential of trauma analysis, the cases with disagreement draw attention to the pitfalls and shortcomings of attempting to reconstruct the death circumstances from skeletal trauma analysis alone.     

Characterization and Comparison of Injuries Caused by Accidental and Non‐accidental Blunt Force Trauma in Dogs and Cats

Motor vehicle accidents (MVA) are often difficult to distinguish from non‐accidental injury (NAI). This retrospective case–control study compared animals with known MVA trauma against those with known NAI. Medical records of 426 dogs and cats treated after MVA and 50 after NAI were evaluated. Injuries significantly associated with MVA were pelvic fractures, pneumothorax, pulmonary contusion, abrasions, and degloving wounds. Injuries associated with NAI were fractures of the skull, teeth, vertebrae, and ribs, scleral hemorrhage, damage to claws, and evidence of older fractures. Odds ratios are reported for these injuries. MVA rib fractures were found to occur in clusters on one side of the body, with cranial ribs more likely to fracture, while NAI rib fractures were found to occur bilaterally with no cranial–caudal pattern. Establishing evidence‐based patterns of injury may help clinicians differentiate causes of trauma and may aid in the documentation and prosecution of animal abuse.     

A Unique Type of Birth Trauma Mistaken for Abuse

Pediatric abusive head trauma is a challenging subject across many disciplines. Of particular importance is the identification of mimics of abuse, so cause and manner of death can be properly assigned. We present the case of suspected child abuse involving an infant who presented unresponsive to the hospital with hypoglycemia, hypothermia, and bilateral parietal fractures. An autopsy revealed fractures associated with organizing scalp hemorrhage and gross leptomeningeal congestion and hemorrhage. The fractures were circular with external displacement, rounded margins, and subperiosteal new bone formation indicative of healing. Birth records revealed vacuum assist and cesarean section delivery. Although vacuum extraction‐related injuries are typically cephalohematomas and/or linear fractures, the outbending and circular morphology of the fractures are consistent with vacuum extraction. Moreover, microscopic neuropathological examination revealed hemorrhagic purulent leptomeningitis. This unique case demonstrates the importance of considering birth trauma in the determination of cause and manner of death of an infant.     

Skeletal Trauma Resulting From Fatal Low (≤3 m) Free Falls: An Analysis of Fracture Patterns and Morphologies

The skeletal trauma resulting from fatal low (≤3 m) free falls is poorly researched and understood by forensic practitioners. The aim of this study was to identify the types of skeletal trauma resulting from low falls through investigating fracture patterns and morphologies. Skeletal trauma was analyzed using full‐body postmortem computed tomography scans of 145 individuals who died from a low free fall. Trauma was then contextualized to the variables that influence how a person falls using multiple logistic regression. Results showed fracture patterning primarily involved the axial skeleton and that there were a number of patterns significantly associated with the height fallen, pre‐existing health conditions, and age. Analysis of fracture morphologies showed 108 possible fracture types, six of which were significantly associated with the height fallen. Understanding the skeletal trauma characteristic of low free falls will further inform anthropological interpretations of trauma in cases where a fall may be considered the possible mechanism.     

Weapon Use in Korean Homicide: Differences Between Homicides Involving Sharp and Blunt Instruments

On the basis of information regarding 276 homicides committed in South Korea between 1987 and 2008, we compared offenders’ and victims’ characteristics, injury locations, weapon‐related behavior, and offending behavior between homicides involving sharp and blunt instruments. The victims of sharp‐force homicide were much younger relative to those of blunt‐force homicide. In addition, homicides involving blunt instruments were more likely to be committed by offenders who lived with the victims. Most sharp‐force homicides involved injuries to the torso, while blunt‐force homicides involved mainly head injuries. Furthermore, perpetrators of sharp‐force homicides tended to preselect their weapons, while those of blunt‐force homicides were likely to use weapons of opportunity. Logistic regression analysis identified a number of factors, including injury location and body transportation, which significantly predicted weapon type. As this was the first South Korean study to compare sharp‐ and blunt‐force homicides, the results have practical implications for homicide investigations.     

Computer Simulations to Investigate the Consequence of Blunt Head Impact

Blunt head impact as sustained in falls or punches against the head can result in rupture of bridging veins. Computer simulations were performed to simulate three different types of falls and punches against the head. The relative brain‐skull motion was recorded. The falls resulted in impact on the backside of the head, whereas the punches struck the face. The maximum resultant translational and rotational acceleration, the Head Injury Criterion (HIC), and the characteristics of the relative brain‐skull motion, as well as the coup and contre‐coup regions were determined. The maximum resultant translational acceleration was found to be between 2982 and 3541 m/s² for falls and between 814 and 942 m/s² for punches. The maximum resultant rotational acceleration reached 632–1000 rad/s² for falls and 252–620 rad/s² for punches. The HIC for falls was found to be at least 1357 and at most 130 for punches. The major brain‐skull displacement calculated for falls and punches was 6.6 and 4.2 mm, respectively. The results of this study suggest that falls are associated with a higher risk for bridging vein ruptures than punches and that cerebral contusions at the contre‐coup side are more serious.     

Histologic evidence of repetitive blunt force abdominal trauma in four pediatric fatalities

In cases of acute fatal child abuse, certain injuries, including cutaneous blunt force trauma, skull fractures, subdural hematomas, intra-abdominal hemorrhage, and retinal hemorrhages are common and well described in the pediatric and forensic literature. These gross findings at autopsy, when taken into consideration with scene investigation and interviews with caregivers, may indicate both a clear manner and cause of death. In such cases, the discovery of additional pathologic changes attributable to older abusive injuries helps support a conclusion of death due to inflicted trauma. We discuss four cases of fatal child abuse in which acute blunt force abdominal trauma was the cause of death. In each of these cases, careful examination with proper sectioning and microscopy of select abdominal tissues revealed that the acute tissue trauma was superimposed on a background of older, healing injury. This older trauma was characterized by classic histologic elements of tissue repair, including fibroblast proliferation, early scar formation, increased vascularity, and hemosiderin-laden macrophages. Iron and trichrome stains were used to confirm the presence of hemosiderin and fibrosis in all four cases, but the recognition of fibroblast proliferation and a reactive vascular pattern was best seen on routine hematoxylin and eosin stains. The gross and microscopic autopsy findings, along with available investigative information, established the diagnosis of chronic physical abuse.     

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.     

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.     

Deaths Due to Child Abuse: A 6‐Year Review of Cases in The Cook County Medical Examiner's Office

Case files from the Cook County Medical Examiner's Office from 2007 to 2012 were reviewed to analyze homicides due to physical child abuse in children <3 years old. Fatal cases mostly involved younger subjects. Intracranial injuries were the leading cause of death, while death due to extracranial injuries was uncommon. Eyes were involved in most of the cases. Spinal cord was involved in about 1/3 of the cases, mostly in the thoracic area. In some cases, previous injuries were present. There were significant differences in the pattern of injuries between age groups. Subjects showing signs of impact to the head and subjects with no evidence of an impact showed no significant difference in internal injuries. The association of multiple injuries is highly suggestive of child abuse. In suspected child abuse, a postmortem examination including neuropathological, ophthalmological, and radiological information should be always evaluated, together with investigative reports and the medical history.