title: Clothing increases the risk of indirect ballistic fractures.
abstract: BACKGROUND
  Current literature has shown the mechanism of how indirect fractures occur but has not determined what factors increase the risks of such fractures. The objective of this study is thus to determine the effect of clothing and soft tissue thickness on the risk of indirect fracture formation.
  
  
  METHODS
  Twenty-five fresh red deer femora embedded in ballistic gelatine were shot with varying distances off their medial cortex with a 5.56 × 45 mm North Atlantic Treaty Organization (NATO) bullet while being filmed with a slow-motion video. We compared the effect of two different gelatine depths and the effect of denim cloth laid onto the impact surface of the moulds.
  
  
  RESULTS
  Bullet passage in thinner moulds failed to cause fracture because the bullet exited the mould before a large expanding temporary cavity was produced. Clothing dramatically altered the size and depth of the expanding cavity, as well as increased lateral pressures, resulting in more severe fractures with greater bullet distances from the bone that can cause fracture.
  
  
  CONCLUSIONS
  Clothing increases the risk of indirect fracture and results in larger, more superficial temporary cavities, with greater lateral pressures than are seen in unclothed specimens, resulting in more comminuted fractures. Greater tissue depth affords the 5.56 × 45 mm NATO a chance to yaw and thus develop an enlarging temporary cavity that is sufficient to cause fracture.
authors.affiliation: Medical Corps, New Zealand Defence Force, Wellington 5045, New Zealand. kieserdavid@gmail.com.
authors.forename: David C
authors.initials: DC
authors.lastname: Kieser
authors.forename: Debra J
authors.initials: DJ
authors.lastname: Carr
authors.forename: Sandra C J
authors.initials: SC
authors.lastname: Leclair
authors.forename: Ian
authors.initials: I
authors.lastname: Horsfall
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Theis
authors.forename: Michael V
authors.initials: MV
authors.lastname: Swain
authors.forename: Jules A
authors.initials: JA
authors.lastname: Kieser
mesh_terms: D000818:Animals; D003020:Clothing / Q000009:adverse effects*; D003670:Deer; D004195:Disease Models, Animal; D004735:Energy Transfer / Q000502:physiology; D005260:Female; D005264:Femoral Fractures / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D044709:Forensic Ballistics / Q000379:methods; D005780:Gelatin; D018570:Risk Assessment / Q000379:methods; D017695:Soft Tissue Injuries / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D014948:Wounds, Gunshot / Q000473:pathology / Q000503:physiopathology*
chemical_list: D005780:Gelatin