Forensic Fractography of Bone: A New Model for Skeletal Trauma Analysis

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This webinar originally occurred on November 2, 2022
Duration: 1.5 hours

Overview

Fractography is a tool for studying material failure. Analysis of cracks and fractures can reveal information about how, why, and where a failure occurred and how a crack traveled. It can help determine the point of fracture origin, identify the presence of flaws and regions of localized stress concentrations, and provide insight into the cause of failure. Fractography is used in a wide range of engineering and forensic applications to investigate material and structural failures, and it has also recently been shown to have useful applications in the analysis of fractured bone in forensic contexts. As a relatively new approach in forensic anthropology, fractography is not yet widely known or understood, and is not commonly taught as part of forensic anthropological educational or training programs. For these reasons, practitioners may feel reluctant to apply fractography in their forensic examinations. This webinar is intended to provide a basic introduction to the practice and application of forensic fractography of bone and make it more approachable and accessible to practitioners. 

Forensic fractography of bone represents a new model for conceptualizing bone failure, which involves a shift from emphasizing typological and morphological descriptions to interpretations based on bone’s mechanical properties, response to force, and different loading regimes. An overview of the science of fractography and its various historical applications, including in anthropology and related fields, will be provided and basic terminology, concepts, and principles will be reviewed.   

A fracture origin refers to the point where a fracture begins. Identification of fracture origin is often critical to understanding the cause of material failure. Fracture origins in bone will be discussed, including how fractures initiate from impacts and other stresses, as well as the role of strength limiting flaws and features in influencing the location(s) of crack origins. Following crack initiation, a fracture extends and propagates under differential stress conditions. The paths of cracks are not random but occur in patterns that are related to stress conditions and material properties. These patterns can provide information about the cause of the fracture, the energy of the fracture, and the stress state. Cracking and breakage patterns in bone will be discussed, including impact site crack patterns, crack branching, fragmentation patterns, and the interpretation of intersecting cracks.  

A fracture surface refers to the surface created by the separation of two portions of a material as a result of a propagating crack front. Fracture surfaces can reveal information about mechanical properties of a material, the mechanism of failure, and origin and propagation direction of the fracture. Fracture surface features of bone will be reviewed, including how to use them to interpret direction of crack propagation. These fractography principles discussed will be supplemented with case examples, including forensic cases involving bone and other material failures which can be very useful in understanding failure in bone.  

A section on procedures, tools, and equipment will also be included, which will review how to prepare samples for fractographic examination, as well as some basic examination and documentation techniques. Bone biology, structure, and loading regimes play important roles in bone failure but will not be covered in detail in this webinar. Similarly, a familiarity with various engineering and materials science principles is useful, but beyond the scope of this webinar. Some useful resources for further study will be provided.  

This webinar will closely follow the content of A Guide to Forensic Fractography of Bone (Christensen et al., 2022), and attendees are encouraged to review this publication prior to the webinar. This publication is available free of charge online HERE.

Detailed Learning Objectives

1. Attendees will learn about the science of fractography and how it can be used to examine and interpret skeletal fractures.
2. Attendees will become acquainted with the tools and equipment needed to effectively apply bone fractography.
3. Attendees will understand that anthropologists can use fractography to enhance understanding of skeletal trauma events with a few basic tools and a little practice.

Presenters

• Angi Christensen, Ph.D., D-ABFA | Forensic Anthropologist, Federal Bureau of Investigation Laboratory
• Mari Isa, Ph.D. | Assistant Professor of Anthropology, Texas Tech University