Bilateral First Rib Anomalous Articulations with Pseudarthroses Mimicking Healing Fractures in an Infant with Abusive Head Injury

Bilateral symmetric bone nodules were observed in the anterolateral first ribs of an infant with shaking injuries at autopsy. The location prompted diagnostic considerations of healing fractures versus anomalous articulations with pseudarthroses. The forensic pathologist worked with forensic anthropologists and pediatric radiologists to evaluate autopsy findings and compare premortem and postmortem X‐rays. Gross examination of the bones by the pathologist and anthropologists confirmed bilateral, callus‐like bone nodules in first‐rib locations associated with pseudarthroses. Histologic examination of one of the bones further showed features most consistent with pseudarthrosis, not a healing fracture. Radiologists then compared multiple premortem and postmortem radiographs that showed no remodeling of the bone over a 2‐week interval between the time of injury and death, which would be unexpected for a healing fracture in an infant. This multidisciplinary approach resulted in the appropriate diagnosis of pseudarthroses due to anomalous articulations, an uncommon finding in forensic pathology.     

A radiographic assessment of pediatric fracture healing and time since injury

Past studies and pediatric bone physiology indicate that younger individuals may heal at a faster rate. Additionally, in adults upper limb fractures heal faster than lower limb fractures; this trend is expected for pediatric fractures. This study aims to evaluate and compare rates of fracture repair in children based on age and skeletal element. Six stages are used to describe the bone repair process in 294 radiographs of tibial and radial fractures from 107 infants and young children. Healing rates are examined using ANOVA and Welch's t-test with a 95% confidence interval. Results indicate that younger individuals spend less time at stage 1, suggesting a delay in the start of healing. Furthermore, forearm fractures heal faster than leg fractures at stages 2 and 3, suggesting a role in the osseous reaction of bone healing. The healing schedule presented may allow the timing of injuries to be estimated from radiographs.     

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.     

Structural analysis of human rib fracture and implications for forensic interpretation

Patterns of rib fractures are of significant clinical and forensic interest. Linking patterns of rib fracture with specific physical events provides a foundation for understanding the nature of traumatic events that are associated with rib fracture in forensic contexts. In this study, isolated human ribs (n = 8) were end-loaded to failure to investigate: (i) local deformations (bone strain) prior to and during structural failure, (ii) location of ultimate failure, and (iii) fracture mode. Structural properties of ribs were used to calculate theoretical stresses to determine whether such calculations could be used to predict site of fracture. Ribs fractured on the sternal side of midshaft in all experiments, but mode of failure varied with transverse, buckle, spiral, and "butterfly" fractures observed. Comparison of calculated stress with observed strain values suggest that experimental, rather than theoretical, approaches will be most productive in furthering understanding rib fracture in forensic contexts.     

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.     

The Erratic Behavior of Lesions in Burnt Bone

This study analyses depressed fractures (by blunt force trauma) and circular full‐thickness injuries (drill injuries and gunshot wounds) in charred bones. Fifty bovine ribs (total 104 lesions) were divided into three groups. The first group consisted in 20 depressed hammer‐produced fractures; in the second one, 60 round drill‐holes were produced (30 circular, 30 semicircular); in the third group, 12 fleshed and 12 skeletonized ribs were hit by 9‐mm bullets. Each specimen was carbonized in an electric oven up to 800°C. Morphological and metric analyses were performed before and after: morphological features were preserved, but depressed fractures showed an increase in their dimensions (p‐value < 0.05); the drilled holes shrunk (p‐value < 0.01); the charring cycle increased the number of fractures in samples with gunshot wounds differently in fleshed and defleshed ribs. This study showed the complex behavior of charred bone, for what concerns the interpretation of trauma and how caution should be applied.     

Early Signs of Fracture Repair in the Human Rib Cage: Implications for Forensic Casework

The decomposed body of a woman discovered beneath a collapsed structure was examined at the C.A. Pound Human Identification Laboratory. Despite a mix of rib fractures with and without indications of healing, it is most likely that all fractures occurred as a result of a single, compressive event. Signs of intramembranous, and possibly direct, fracture healing at the incomplete fractures without signs of endochondral ossification at the complete fractures suggest the individual died very shortly—but not immediately—after injury. Given the case circumstances, the findings inform immediate cause of death. This case study highlights that differential healing as a result of a single event is possible. Further, it illustrates the importance of careful examination of micro‐discontinuities/cracks that can occur in association with major fractures. Fracture healing and dating data are discussed, as is the possible need for critical evaluation of the antemortem/perimortem boundary.     

A Four‐Stage Method of Age at Death Estimation for Use in the Subadult Rib Cortex*,†

Abstract: Age estimation in the subadult skeleton can be rather precise when the epiphyses and dentition are present, but incomplete or commingled remains still present a challenge. Histomorphometric age‐at‐death estimation methods developed for use on adults are based on the age‐associated accumulation of osteons. In the growing skeleton, there is a poor correlation between osteon numbers and age until the latter half of the second decade. As a result, there has been no histological aging method for use in subadults. The analysis of the rib cortex of 72 subadults ranging in age from 2 to 21 years has identified a series of developmental changes in the bone microstructure that can be used to estimate age. This qualitative method utilizes the systematic changes in rib cortical morphology to classify ribs into one of four age phases. This method can be applied to immature skeletons in forensic, archaeological, and paleontological contexts.     

Planned Complex Occupation‐related Suicide by Captive‐bolt Gunshot and Hanging*

Abstract: Planned complex suicides are committed by using two or more previously planned methods simultaneously to make sure that death will occur even if one method fails. Herein, we presented a case of occupation‐related planned complex suicide, committed by captive‐bolt gunshot and hanging. A 29‐year‐old man, who worked as a butcher, was found dead in the stable, hanging by the neck with a captive‐bolt gun embedded in the forehead region of his head. The hanging was complete. Along the bolt canal were bone fragments, and at the end of the path was the punched‐out fragment of the skin and soft tissue. There were no fractures of the hyoid bone and laryngeal cartilages, and a superficial hemorrhage was present in the right sternocleidomastoid muscle. Our case underlines the utility of forensic autopsy and death scene investigation in reconstructing the mechanism of death, as well as the dynamics of the event.     

Less‐Lethal Hybrid Ammunition Wounds: A Forensic Assessment Introducing Bullet‐Skin‐Bone Entity

Abstract: Agencies all around the world now use less‐lethal weapons with homogeneous missiles such as bean bag or rubber bullets. Contusions and sometimes significant morbidity have been reported. This study focuses on wounds caused by hybrid ammunition with the pathologists’ flap‐by‐flap procedure. Twenty‐four postmortem human subjects were used, and lesions caused on frontal, temporal, sternal, and left tibial regions by a 40‐mm hybrid ammunition (33 g weight) were evaluated on various distance range. The 50% risk of fractures occurred at 79.2 m/sec on the forehead, 72.9 m/sec on the temporal, 72.5 m/sec on the sternum, and 76.7 m/sec on the tibia. Skin lesions were not predictors of bone fracture. There was no correlation between soft and bone tissue observed lesions and impact velocity (correlated to distance range). Lesions observed with hybrid ammunition were the result of bullet‐skin‐bone entity as the interaction of the projectile on skin and bone tissues.     

An Anthropological Examination of the Types of Skeletal Fractures Resulting from Fatal High (˃3 m) Free Falls,

Fatal falls from heights (?3 m) often result in blunt force trauma (BFT) to the skeleton. The fracture patterns that result from this BFT mechanism are well understood in forensic anthropology and forensic pathology; however, details of the specific types of fractures that result remain poorly documented. The aim of this study was to provide a detailed examination of the types of fractures that may result from fatal high falls. Fractures were recorded from 95 full‐body postmortem computed tomography scans of individuals known to have died from a high fall. Trauma was then analyzed taking into account the extrinsic and intrinsic variables known to influence a fall using multiple logistic regression. A total of 339 types of fractures were classified, of which 16 were significantly associated with this BFT mechanism. Classified fracture types will augment anthropological interpretations of the circumstances of death from BFT in cases of suspected high falls.     

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.     

Assessing Impact Direction in 3‐point Bending of Human Femora: Incomplete Butterfly Fractures and Fracture Surfaces,,

Current literature associates bending failure with butterfly fracture, in which fracture initiates transversely at the tensile surface of a bent bone and branches as it propagates toward the impact surface. The orientation of the resulting wedge fragment is often considered diagnostic of impact direction. However, experimental studies indicate bending does not always produce complete butterfly fractures or produces wedge fragments variably in tension or compression, precluding their use in interpreting directionality. This study reports results of experimental 3‐point bending tests on thirteen unembalmed human femora. Complete fracture patterns varied following bending failure, but incomplete fractures and fracture surface characteristics were observed in all impacted specimens. A flat, billowy fracture surface was observed in tension, while jagged, angular peaks were observed in compression. Impact direction was accurately reconstructed using incomplete tension wedge butterfly fractures and tension and compression fracture surface criteria in all thirteen specimens.     

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.     

Applicability of Cranial Models in Urethane Resin and Foam as a Substitute for Bone: Are Synthetic Materials Reliable?

As literature is poor in functional synthetic cranial models, in this study, synthetic handmade models of cranial vaults were produced in two different materials (a urethane resin and a self‐hardening foam), from multiple bone specimens (eight original cranial vaults: four human and four swine), in order to test their resemblance to bone structure in behavior, during fracture formation. All the vaults were mechanically tested with a 2‐kg impact weight and filmed with a high‐speed camera. Fracture patterns were homogeneous in all swine vaults and heterogeneous in human vaults, with resin fractures more similar to bone fractures. Mean fracture latency time extrapolated by videos were of 0.75 msec (bone), 1.5 msec (resin), 5.12 msec (foam) for human vaults and of 0.625 msec (bone), 1.87 msec (resin), 3.75 msec (foam) for swine vaults. These data showed that resin models are more similar to bone than foam reproductions, but that synthetic material may behave quite differently from bone as concerns fracture latency times.     

Characteristics and Frequency of Chipping Effects in Near‐Contact Gunshot Wounds

The presence of “chipping” or “flaking” around the edges of gunshot entry wounds has been described among the characteristics of gunshot wounds in bone. In this study, the real frequency of such a peculiar feature was investigated. The presence of “chipping” was assessed on 22 gunshot wounds fired at a near‐contact range on bovine ribs with 9‐mm bullets. As controls, five samples were shot with a 3 cm range, and five from 40 cm. In 77% of cases shot at near‐contact range, a detachment of small fragments of the upper layers of bone was detected, mainly with a circumferential disposition, whereas this feature was lacking in control samples. The study demonstrated the frequency of “chipping” and that it may probably be due to a combined ballistic effect of impact of the bullet itself and expansion of gases. It may be thus considered indicative of close‐range shots.     

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.     

Flail Chest Following Failed Cardiopulmonary Resuscitation

Following the death of a woman with blunt force chest trauma, the question was asked how common was the finding at autopsy of a flail chest in decedents after failed cardiopulmonary resuscitation. It was suggested in court that this was an uncommon occurrence. To address this issue, autopsy cases in adults (>18 years) with rib fractures attributable to cardiopulmonary resuscitation were taken from the files of Forensic Science SA over a 7‐year period from 2008 to 2014. Flail chest injuries were defined as those arising from fractures at two sites in at least three consecutive ribs. From 236 cases with rib fractures attributed to resuscitation, a total of 43 flail chest injuries were found in 35 cases (14.8%). The majority occurred in the 60‐79‐year‐old age group. These data suggest that flail chest injuries are a more common sequelae of cardiopulmonary resuscitation than has been previously appreciated in autopsy cases, particularly in the elderly.     

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.     

Case report: Forensic anthropological assessment in a suspected case of child abuse from South Africa

Not many case reports of suspected child abuse as assessed solely on skeletal remains are available. Forensic anthropologists have intimate knowledge of normal skeletal anatomy, bone trauma and processes of healing of bone and may therefore be of help in suspected cases of child abuse. Patterns of trauma in juvenile skeletal remains which are suggestive of abuse include fractures in different phases of healing, multiple fractures, typical fractures on ribs and long bones and severe, complicated cranial fractures. The aim of this paper is to report on the findings of the analysis of the skeletal remains of a 3.5 years old boy. Forensic pathological examination indicated that the boy had died from a massive cranial fracture, with multiple injuries present to the rest of the body. After the body had been buried for some time, it was exhumed and we were requested to look for signs of chronic, long-term abuse. Findings included a massive cranial fracture, another fracture in the roof of the orbit, two areas of non-specific subperiosteal bone growth and several untreated carious teeth. No clear healed fracture could be found, except for a possible healed cranial base fracture which stretched transversely across the petrosal bone. This area showed signs of recent bone activity. The court decided that this was not enough evidence of chronic abuse and found the accused guilty of murder but not of chronic child abuse. This case illustrates the difficulty to obtain clear signs of chronic injury on juvenile remains.