title: Stabbing energy and force required for pocket-knives to pierce ribs.
abstract: OBJECTIVE
  In addition to reconstructing the course of events, the medical examiner will often have to answer questions regarding the force necessary to inflict a certain injury in stabbing incidents. Several groups have examined the force needed to penetrate soft-tissue and clothing; however, no studies addressing the energy needed for penetrating ribs exist. Therefore, we decided to investigate this force on an animal model.
  
  
  METHODS
  Ribs from healthy, 8 to 10-month-old pigs were used as a substitute for human ribs. These ribs were then stabbed either transversely or longitudinally with two different pocket-knife blades, namely a Swiss Army pocket knife and a sturdier pocket knife (Classic Schnitzmesser, Herbertz Solingen) dropped from a drop-tower at defined heights and therefore defined energies.
  
  
  RESULTS
  Longitudinally orientated stabs showed complete piercing of the ribs at approximately 11 Joules (J) or with a stabbing force in excess of 906 Newton (N) for both blade types. Transversely orientated stabs, however, displayed complete piercing between 11 and 16 J, or in excess of 1198 N, with the sturdy pocket knife tending to require a little more energy than the Swiss army pocket knife.
  
  
  CONCLUSIONS
  Young adult porcine ribs are completely pierced by pocket knife blades at energies between 11 and 16 J. Assuming the porcine ribs are comparable to those ribs of young adult humans, our results indicate that a complete penetration of the chest wall through the ribs by stabbing with a pocket knife is rather easily achieved.
authors: Department of Forensic Medicine and Imaging, Zurich Institute of Forensic Medicine, University of Zurich, Winterthurerstrasse 190/52, 8057, Zurich, Switzerland. stephan.bolliger@irm.uzh.ch.
authors: Stephan A
authors: SA
authors: Bolliger
authors: BPK Consulting, Thun, Switzerland.
authors: Beat P
authors: BP
authors: Kneubuehl
authors: Department of Forensic Medicine and Imaging, Zurich Institute of Forensic Medicine, University of Zurich, Winterthurerstrasse 190/52, 8057, Zurich, Switzerland.
authors: Michael J
authors: MJ
authors: Thali
authors: Department of Forensic Medicine and Imaging, Zurich Institute of Forensic Medicine, University of Zurich, Winterthurerstrasse 190/52, 8057, Zurich, Switzerland.
authors: Sebastian
authors: S
authors: Eggert
authors: Institute of Forensic Medicine, Centre for Forensic Physics and Ballistics, University of Bern, Bern, Switzerland.
authors: Lea
authors: L
authors: Siegenthaler
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D049429:Forensic Pathology; D023421:Models, Animal; D012272:Ribs / Q000293:injuries* / Q000473:pathology*; D013552:Swine; D054041:Weapons; D014951:Wounds, Stab / Q000473:pathology* / Q000503:physiopathology
keywords: Forensic; Pocket-knife; Rib piercing; Stab energy; Stab force