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%.

Characteristics and time-dependence of cut marks and blunt force fractures on costal cartilages: an experimental study

“…In the study of cartilage stab injuries, Pounder et al [13][14][15] also made an important contribution, demonstrating that striation marks left by serrated knives might enable the identification of a class characteristic of serrated blades. Love et al [16] confirmed the results provided by the study of Pounder et al but also demonstrated that a blade type classification may lead to high misclassification rates. Two further studies performed by Pounder et al [17,18] on soft tissues showed that the identification of a stab injury may be easier when the stabbing tool is held perpendicular to the wounded tissue.…”

“…Costal cartilage can be very important in real case scenarios as it is injured in many cases of stab wounds to the chest. Previous studies demonstrated that characteristic cut marks may also be detected on cartilage, especially when serrated-edged blades are used, thereby providing crucial aid in the identification of the wounding weapon [12][13][14][15][16]. At the moment, however, the microscopic differences between cut marks and blunt force fractures on cartilage, along with the modifications they undergo when decomposition occurs, have never been thoroughly investigated.…”

Microscopic Saw Mark Analysis: An Empirical Approach

“…Three doctoral level anthropologists examined each specimen independently. Each analyst has a minimum of 6 years of experience analyzing tool marks in bone and cartilage and previously participated in a knife cut mark validation study . To ensure that each analyst understood the variables, a pilot study of 10 saw marks was conducted.…”

An investigation of the use of discriminant analysis for the classification of blade edge type from cut marks made by metal and bamboo blades

“…Previous studies on cut marks have involved the use of qualitative description of the features of bone surface disruption, using either light microscopy or Scanning Electron Microscopy (SEM) (Bromage and Boyde, 1984;Greenfield, 1999;West and Louys, 2007;Love et al, 2012). Recently, authors have begun to look at quantitative analysis (Bello and Soligo, 2008;Bello et al, 2009) and the use of three dimensional microscopy (Boschin and Crezzini, 2011).…”

“…Porcine ribs were chosen as they are a commonly selected species for this type of study (Croft and Ferllini, 2007;Kooi and Fairgrieve, 2012;Love et al, 2012). There was no disruption of the overlying soft tissue in the central areas of the ribs to be used, therefore no pre-existing cut marks from the processing of the meat.…”