ORIGINAL ARTICLE Morphoscopic analysis of experimentally produced bony wounds from low-velocity ballistic impact Jules A. Kieser • Joy Tahere • Caitlin Agnew • David C. Kieser • Warwick Duncan • Michael V. Swain • Matthew T. Reeves Accepted: 1 April 2011 / Published online: 1 May 2011 Ó Springer Science+Business Media, LLC 2011 Abstract Understanding how bone behaves when sub- jected to ballistic impact is of critical importance for forensic questions, such as the reconstruction of shooting events. Yet the literature addressing microscopic anatomical features of gunshot wounds to different types of bone is sparse. More- over, a biomechanical framework for describing how the complex architecture of bone affects its failure during such impact is lacking. The aim of this study was to examine the morphological features associated with experimental gun- shot wounds in slaughtered pig ribs. We shot the 4th rib of 12 adult pigs with .22 mm subsonic bullets at close range (5 cm) and examined resultant wounds under the light microscope, scanning electron microscope SEM and micro tomograph lCT. In all cases there was a narrow shot channel followed by spall region, with evidence of plastic deforma- tion with burnishing of the surface bone in the former, and brittle fracture around and through individual Haversian systems in the latter. In all but one case, the entrance wounds were characterized by superficially fractured cortical bone in the form of a well-defined collar, while the exit wounds showed delamination of the periosteum. Inorganic residue was evident in all cases, with electron energy dispersive spectroscopy EDS confirming the presence of carbon, phosphate, lead and calcium. This material appeared to be especially concentrated within the fractured bony collar at the entrance. We conclude that gunshot wounds in flat bones may be morphologically divided into a thin burnished zone at the entry site, and a fracture zone at the exit. Keywords Forensic science Á Gunshot Á Ballistics Á Trauma Á Wounding Introduction Wound ballistics is the science of injuries caused by pro- jectiles that impact or penetrate the body [1]. In forensic science, examination and analysis of gunshot entry wounds is important because it can provide useful information in the reconstruction of shooting scenes, such as the type of projectile involved as well as the angle from whence it was discharged [2, 3]. Assuming that one considers a given type of bullet fired from a given distance, Karger [4] has argued that there are two crucial factors to be considered in evaluating the resultant tissue damage; firstly, the location of the energy-transfer within the shot channel; and sec- ondly, the elasticity of the tissues involved. In other words, the less flexible the tissue is, the more damage will result, simply because less energy will be transferred to the stretch-mechanism involved in temporary cavitation [5, 6]. When considering wounding of flat bones such as the cranium or ribs, internal bevelling has been suggested to be the hallmark of an entrance wound, with its shape and diameter thought to be associated with the line of fire, the type of weapon and the caliber of projectile involved [7, 8]. There are of course well documented exceptions such as external bevelling, absence of bevelling and keyhole J. A. Kieser (&) Á J. Tahere Á C. Agnew Á W. Duncan Á M. V. Swain Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, PO Box 647, Dunedin 9016, New Zealand e-mail: jules.kieser@otago.ac.nz D. C. Kieser Department of Orthopaedic Surgery, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand M. T. Reeves Department of Physics, University of Otago, Dunedin, New Zealand 123 Forensic Sci Med Pathol (2011) 7:322–332 DOI 10.1007/s12024-011-9240-y