Machete Cut Marks on Bone: our Current Knowledge Base

Abstract

Perspective PerspectiveForensic anthropology has traditionally dealt with identifying a biological profile of the deceased, including the estimated age at death, sex, height, and ethnicity. Over the past few decades the remit of forensic anthropology has expanded to include the identification of the weapons responsible for blunt and sharp force trauma and gunshot wounds. The majority of forensic research on hacking trauma on bone was first derived from archaeological studies [1][2][3][4], followed by experiments that have mainly focused on knife [5][6][7][8], and saw tool marks [9][10]. The use of weapons of opportunity (eg. shovels, saws, shears, machetes) in war crimes, genocide and contemporary crime and the absence of eye witness accounts, has led to the need to identify the specific marks different weapons leave on bone. While multiple types of weapons are used in physical assaults, the machete has seen a significant rise in its use and media attention [11].Burd and Gilmore reported that no two implements will produce the same tool mark and nor will the same tool produce an identical mark [12]. When used with sufficient force, sharp weapons leave marks that potentially provide individual and class characteristics on bone. Additionally, sharp force hacking trauma is essentially a blunt force trauma inflicted by a sharp object, and thus the analysis of the complete bone is necessary. One of the most important factors identified by Maples [13] was that when the sharp edge of a machete is used on live flesh or fresh bone, the cortex is compressed to the sides and when it is withdrawn, the elasticity of the bone will tend to close the cortical wound. This results in a wound width that is smaller than the blade that caused it, thus rendering wound thickness as an identifying weapon trait unreliable, a fact that has largely been ignored in tool mark identification.The first attempt at distinguishing sword from axe cut marks on bone, independent of weapon/blade type, was undertaken by Wenhem [14]. Using six archaeological specimens with a total of 38 cut marks, Wenham established three criteria for distinguishing between the weapons. However, the type of swords used is unknown and no details regarding the experiments are provided.Recent forensic experiments have focused on hacking trauma by large bladed weapons used for dismemberment, including the machete. Humphrey and Hutchinson [15], defined hacking trauma made by a machete, a cleaver and an axe on partially fleshed porcine limb sections. Twenty eight bones with a total of 58 cut marks were analysed. The results summarised in Table 1 & 2 indicate three defined classes of hacking trauma. They argue that hacking trauma could be differentiated based on size, shape and breakage associated with the different classes' cut marks and that these wound pattern characteristics were sufficiently different to make a reasonable judgment as to what weapon was used. However, the possible cortical wound closing, or possible partial closing was not considered, nor was the depth o...

Interpersonal violence in colonial era in Papua, Indonesia: A case study of trauma patterns of a Biak individual

“…For Lesion A, the size, shape, angle, v‐shaped kerf, hinge fracture, and large flake are characteristics of a wound caused by a machete‐like implement. For Lesion B, the size, shape, broken flake, and radiating fracture are also characteristics of machete wounds (Lewis, 2008; McCardle & Lyons, 2015). Importantly, parang is known as the weapon of choice for hand‐to‐hand battles in Papua (Badjang, 1963).…”

“…It was possible to use a thin piece of wire to gently probe and confirm that Lesion B went through the entire diploic bone. It is likely that the short width of the lesion resulted from the "closure" of the wound due to bone elasticity when the weapon was removed (McCardle & Lyons, 2015). A 6-mm wide flake of bone had been broken off along the lateral anterior portion of the fracture line toward the squamosal suture, and there was a hairline fracture radiating inferiorly from this point of the lesion.…”

Cruel traces: Bone surface modifications and their relevance to forensic science

“…Sharp instruments (i.e., objects that are edged, pointed, and/or beveled) hold the potential to create many types of marks on bone surfaces in both the perimortem and postmortem intervals (Love, 2019; McCardle & Lyons, 2015; Reichs, 1998; Symes, Chapman, Rainwater, Cabo, & Myster, 2010). Here, we distinguish four types of sharp‐force BSMs: cut marks, punctures, chop marks, and saw marks.…”

“…A chop mark results from a single or multiple hacking motion(s) directed at an angle or perpendicularly to a bone surface. While punctures and especially chop marks are considered blunt‐force trauma with a sharp object when they create conspicuous fractures and infractions (Symes et al, 2002, p. 407, 2012, p. 365; McCardle & Lyons, 2015, p. 1)—the Spanish and Portuguese forensic literature even uses the specific term cortocontundente for sharp‐blunt hacking marks (Ross & Radisch, 2019, p. 170)—we consider them as sharp‐force BSMs here. A saw mark forms by reciprocating or circular actions on a bone surface (Figure 3).…”