Jason M. Wiersema

Quantitative analysis of sharp-force trauma: an application of scanning electron microscopy in forensic anthropology.

Scanning electron microscopy (SEM) has occasionally been used by anthropologists and forensic scientists to look at morphological characteristics that certain implements leave on bone. However, few studies have addressed techniques or protocols for assessing quantitative differences between tool marks on bone made by different bladed implements. In this study, the statistical variation in cut mark width was examined between control and test samples on bone using a scalpel blade, paring knife, and kitchen utility knife. Statistically significant differences (p < .0005) were found between cut marks made by the same knife under control and test conditions for all three knife types used in the study. When the control sample and test samples were examined individually for differences in mean variation between knife types, significant differences were also found (p < .0005). While significant differences in cut mark width were found, caution should be used in trying to classify individual cut marks as being inflicted by a particular implement, due to the overlap in cut mark width that exists between different knife types. When combined, both quantitative and qualitative analyses of cut marks should prove to be more useful in trying to identify a suspect weapon. Furthermore, the application of SEM can be particularly useful for assessing many of these features.

Skeletal atlas of child abuse

Skeletal atlas of child abuse / , Skeletal atlas of child abuse / , کتابخانه دیجیتال جندی شاپور اهواز

Validation of Tool Mark Analysis of Cut Costal Cartilage

Abstract:  This study was designed to establish the potential error rate associated with the generally accepted method of tool mark analysis of cut marks in costal cartilage. Three knives with different blade types were used to make experimental cut marks in costal cartilage of pigs. Each cut surface was cast, and each cast was examined by three analysts working independently. The presence of striations, regularity of striations, and presence of a primary and secondary striation pattern were recorded for each cast. The distance between each striation was measured. The results showed that striations were not consistently impressed on the cut surface by the blade’s cutting edge. Also, blade type classification by the presence or absence of striations led to a 65% misclassification rate. Use of the classification tree and cross‐validation methods and inclusion of the mean interstriation distance decreased the error rate to c. 50%.

Microscopic Saw Mark Analysis: An Empirical Approach

Microscopic saw mark analysis is a well published and generally accepted qualitative analytical method. However, little research has focused on identifying and mitigating potential sources of error associated with the method. The presented study proposes the use of classification trees and random forest classifiers as an optimal, statistically sound approach to mitigate the potential for error of variability and outcome error in microscopic saw mark analysis. The statistical model was applied to 58 experimental saw marks created with four types of saws. The saw marks were made in fresh human femurs obtained through anatomical gift and were analyzed using a Keyence digital microscope. The statistical approach weighed the variables based on discriminatory value and produced decision trees with an associated outcome error rate of 8.62–17.82%.

The Utility of Forensic Anthropology in the Medical Examiner's Office

Over the past few decades, the field of forensic anthropology has seen major advancements and experienced a considerable growth of professionals in medical examiner/coroner offices. Despite this expansion, misconceptions regarding the role and utility of the anthropologist in the medicolegal setting still exist. This article brings together practitioners employed full-time in four medical examiners offices, with each practitioner providing a unique perspective and emphasis regarding their role as an anthropologist. Discussed is the history of the anthropology division in each office as well as the types of casework and ancillary duties completed by the anthropologists. Consistently, the anthropologists are involved in the search and recovery of human remains, managing long-term unidentified cases, facilitating disposition of unclaimed decedents, and developing mass disaster protocols for their respective agency. Also consistent across the four offices is the fact that the anthropologists receive far more consult requests for trauma evaluation of nonskeletonized cases than any other type of case.

The Value of the Pediatric Skeletal Examination in the Autopsy of Children

The pediatric skeletal examination (PSE) is an autopsy technique recommended for pediatric cases suspicious for nonaccidental injury. The technique requires the reflection of the musculature and periosteum of the ribs, clavicles, long bones, and scapulae, and inspection of the bone surfaces and chondro-osseous interfaces. The technique is time consuming, labor intensive and possibly disfiguring. Therefore, the value of the technique must be measured against the cost. The present study was designed to evaluate the impact of the PSE on the sensitivity of the autopsy. A non-randomized retrospective review of 94 autopsy reports was done. The cause and manner of death for each case was classified as blunt force trauma and homicide. Half of the sample received a PSE during the autopsy and half did not. The number of rib and long bone fractures noted in the reports was significantly greater in the group that received the PSE. The number of cranial, scapular and clavicular fractures was not significantly different between the two groups. The PSE does not increase the visibility of the neurocranium; therefore, a difference in the number of cranial fractures was not expected. Scapular and clavicular fractures were rare in the study population. The insignificant difference between the two groups may be a reflection of the rarity of the fracture as opposed to the sensitivity of the PSE. The results of the study indicate that the PSE increases the sensitivity of the pediatric autopsy with respect to long bone and rib fractures.

The Forensic Anthropologist in the Mass Fatality Context

Mass fatality incidents require a multi-agency, multidisciplinary response to effectively and efficiently manage the recovery and identification of human remains. The forensic anthropologist is uniquely suited for a significant role in the disaster response, demonstrated in the recovery and triage of human remains, interpretation of skeletal trauma, and identification of victims. However, the majority of published literature discusses these response operations in the context of large-scale incidents with significant numbers of highly fragmented and commingled human remains, which does not reflect the operational reality of mass fatality incidents in the United States. This article provides a realistic definition of the term “mass fatality incident” for medicolegal jurisdictions and provides the contributions of the forensic anthropologist for all types of incidents.

Evolution of Forensic Anthropological Methods of Identification

Forensic identification of human remains has long been a core contribution of forensic anthropologists to death investigations. The array and scientific robusticity of the identification methods employed by the anthropologist has evolved in the last several decades, and as with other nonidentification methods, anthropologists have embraced the progression toward the use of validated and statistically defensible methods for identification. This article presents an overview of the role that the forensic anthropologist plays in the identification of human remains and the evolution of anthropological methods of identification.

Skeletal Trauma: An Anthropological Review

As anthropologists take on a larger role in medical examiners offices, the incorporation of bone trauma analysis into the autopsy increases. The purpose of this invited review is to summarize recent anthropological literature that exemplifies the value of forensic anthropology in medicolegal death investigation, concentrating in the area of skeletal trauma analysis. Forensic anthropologists have a strong understanding of bones response to trauma, gained through research and case studies. With this body of knowledge they are able to examine and interpret skeletal injury resulting from blunt, sharp, firearm, and thermal trauma. For example, toolmark class characteristics are recognized through sharp force injury examination, and fracture pattern analysis provides details of the impacting surface area. Interpretation of skeletal trauma allows for reconstruction of events surrounding death, and may inform the manner of death classification.

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.