The Identification and Classification of Sharp Force Trauma on Bone Using Low Power Microscopy

Links

Abstract

Cut mark analysis to date has been intermittently and superficially researched across a range of disciplines, despite its potential to significantly contribute to criminal investigation. The current study aims to elucidate cut mark analysis by proposing a novel classification system for the identification of knife cuts (kerfs) in bone. The system was devised, to record accurate and reliable information about cut marks and the criteria were tested for association with the knives that created them. Optical Microscopy was used to examine knife cuts on fleshed porcine bone. Incised cuts were made by a range of serrated, scalloped and fine-edged blades (n=9), by the author, and participants (n=23) were recruited to make marks on bone under the same force-measured conditions, using the Kistler force plate and a bespoke frame to control the level of height to which the knife can be raised above the bone prior to impact. Resultant kerfs were created by a single operator (n=86) and created by a range of individuals (n=186). The data suggests that consistent force was not achieved and the resultant marks on the bones made by the same knife had wide variation in their appearance and depth. The classification criteria tested did not provide discrete identification of knife blades from the assessment of kerf features; however, trends were identified from criteria including margin regularity, margin definition, floor width and wall gradient, which may form the basis for further investigation. Marks made by a single operator showed more significant associations (p<0.05) than group operators, and although kerfs from each share some trends, several significant relationships observed in marks made by a single operator are not shared by the participant group. Limitations of using optical microscopy included the inability to view all aspects of each mark, particularly when combined with variation in depth and angle produced by human operators. From the present results, it is suggested that the use of digital microscopy with a superior ability to build three dimensional images of indented marks would provide the necessary step forward to improve discrimination between knife classifications, based on the areas highlighted by the current research. This reinforces the need for further understanding of the mechanics of cut mark application in human individuals and their potential effects on kerf features.

Cited Works (20)

Year	Entry
1991	Hunt AC, Cowling RJ. Murder by stabbing. Forensic Sci Int. December 1991;52(1):107-112.
2008	Gilchrist MD, Keenan S, Curtis M, Cassidy M, Byrne G, Destrade M. Measuring knife stab penetration into skin simulant using a novel biaxial tension device. Forensic Sci Int. May 2, 2008;177(1):52-65.
2000	Rogde S, Hougen HP, Poulsen K. Homicide by sharp force in two Scandinavian capitals. Forensic Sci Int. March 27, 2000;109(2):135-145.
2003	Banasr A, de la Grandmaison GL, Durigon M. Frequency of bone/cartilage lesions in stab and incised wounds fatalities. Forensic Sci Int. January 2003;131(2-3):131-133.
2009	Lynn KS, Fairgrieve SI. Microscopic indicators of axe and hatchet trauma in fleshed and defleshed mammalian long bones. J Forensic Sci. July 2009;54(4):793-797.
1996	Miller SA, Jones MD. Kinematics of four methods of stabbing: a preliminary study. Forensic Sci Int. September 30, 1996;82(2):183-190.
1999	Horsfall I, Prosser PD, Watson CH, Champion SM. An assessment of human performance in stabbing. Forensic Sci Int. June 28, 1999;102(2-3):79-89.
2005	Horsfall I, Watson C, Champion S, Prosser P, Ringrose T. The effect of knife handle shape on stabbing performance. Appl Ergon. July 2005;36(4):505-511.
1975	Knight B. The dynamics of stab wounds. Forensic Sci. November–December 1975;6(3):249-255.
2006	Ambade VN, Godbole HV. Comparison of wound patterns in homicide by sharp and blunt force. Forensic Sci Int. January 27, 2006;156(2-3):166-170.
2009	Thompson TJU, Inglis J. Differentiation of serrated and non-serrated blades from stab marks in bone. Int J Legal Med. March 2009;123(2):129-135.
1999	Chadwick EKJ, Nicol AC, Lane JV, Gray TGF. Biomechanics of knife stab attacks. Forensic Sci Int. November 25, 1999;105(1):35-44.
1994	Rouse DA. Patterns of stab wounds: a six year study. Med Sci Law. January 1994;34(1):67-71.
1999	O’Callaghan PT, Jones MD, James DS, Leadbeatter S, Holt CA, Nokes LDM. Dynamics of stab wounds: force required for penetration of various cadaveric human tissues. Forensic Sci Int. October 1999;104(2-3):173-178.
1966	Weaver JK. The microscopic hardness of bone. J Bone Joint Surg. March 1966;48A(2):273-288.
1992	Symes SA. Morphology of Saw Marks in Human Bone: Identification of Class Characteristics [PhD thesis]. Knoxville, University of Tennessee; May 1992.
2001	Bartelink EJ, Wiersema JM, Demaree RS. Quantitative analysis of sharp-force trauma: an application of scanning electron microscopy in forensic anthropology. J Forensic Sci. November 2001;46(6):1288-1293.
2006	Schmidt U, Pollak S. Sharp force injuries in clinical forensic medicine: findings in victims and perpetrators. Forensic Sci Int. June 2, 2006;159(2-3):113-118.
2009	Lynn KS, Fairgrieve SI. Macroscopic analysis of axe and hatchet trauma in fleshed and defleshed mammalian long bones. J Forensic Sci. July 2009;54(4):786-792.
1998	Rho J-Y, Kuhn-Spearing L, Zioupos P. Mechanical properties and the hierarchical structure of bone. Med Eng Phys. 1998;20(2):92-102.

Cited By (3)

Year	Entry
2020	Hogue M, Fairgrieve SI, Lievers WB. Stabbing angle alters peak force and work during sharp force trauma of porcine ribs. Forensic Sci Int. September 2020;314:110373.
2021	Waltenberger L, Beitel S, Benecker B, Heimel P, Weninger W, Kanz F. A histological comparison of non-human rib models suited for sharp force trauma analysis. Forensic Sci Int. February 2021;319:110661.
2022	Hogue M. Effects of Blade Angle on the Force and Work During Sharp Force Trauma of Porcine Ribs [Master's thesis]. Sudbury, ON: Laurentian University; 2022.