Assessment of wear-related features of the kerf wall from saw marks in bone

Abstract

Analyses of saw marks in bone may yield important information about the class characteristics of saws used in postmortem dismemberments, yet little research has been directed at identifying saws' individualizing characteristics. This study adds to existing saw mark analysis methodologies by examining wear-related features of kerf walls using light- and environmental scanning electron microscopy. A crosscut saw and hacksaw were used to create sequences of 30 cuts in bone; these sequences reveal patterns of progressive loss of fine details of kerf wall morphology with increasing saw blade wear, because of the rounding of sharp points and edges. Nevertheless, diagnostic kerf wall features used to establish class characteristics persist despite these wear-related changes. Unsuccessful attempts at statistical analysis of wear-related changes, based on striae width and density, suggest these patterns are not readily quantifiable. Additionally, despite the scanning electron microscope's superior imaging capabilities, it provided few practical, methodological gains over traditional light microscopy. © 2010 American Academy of Forensic Sciences.