title: Injuries of the head from backface deformation of ballistic protective helmets under ballistic impact.
abstract: Modern ballistic helmets defeat penetrating bullets by energy transfer from the projectile to the helmet, producing helmet deformation. This deformation may cause severe injuries without completely perforating the helmet, termed "behind armor blunt trauma" (BABT). As helmets become lighter, the likelihood of larger helmet backface deformation under ballistic impact increases. To characterize the potential for BABT, seven postmortem human head/neck specimens wearing a ballistic protective helmet were exposed to nonperforating impact, using a 9 mm, full metal jacket, 124 grain bullet with velocities of 400-460 m/s. An increasing trend of injury severity was observed, ranging from simple linear fractures to combinations of linear and depressed fractures. Overall, the ability to identify skull fractures resulting from BABT can be used in forensic investigations. Our results demonstrate a high risk of skull fracture due to BABT and necessitate the prevention of BABT as a design factor in future generations of protective gear.
authors.affiliation: Center of Applied Biomechanics, University of Virginia, 4040 Lewis N Clark Drive, Charlottesville, VA, 22911.
authors.forename: Karin A
authors.initials: KA
authors.lastname: Rafaels
authors.forename: Hattie C
authors.initials: HC
authors.lastname: Cutcliffe
authors.forename: Robert S
authors.initials: RS
authors.lastname: Salzar
authors.forename: Martin
authors.initials: M
authors.lastname: Davis
authors.forename: Brian
authors.initials: B
authors.lastname: Boggess
authors.forename: Bryan
authors.initials: B
authors.lastname: Bush
authors.forename: Robert
authors.initials: R
authors.lastname: Harris
authors.forename: Mark Steve
authors.initials: MS
authors.lastname: Rountree
authors.forename: Ellory
authors.initials: E
authors.lastname: Sanderson
authors.forename: Steven
authors.initials: S
authors.lastname: Campman
authors.forename: Spencer
authors.initials: S
authors.lastname: Koch
authors.forename: Cameron R
authors.initials: CR
authors.lastname: Dale Bass
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D002102:Cadaver; D003288:Contusions / Q000473:pathology; D004867:Equipment Design; D044709:Forensic Ballistics; D049429:Forensic Pathology; D006260:Head Protective Devices; D006801:Humans; D008297:Male; D008875:Middle Aged; D011859:Radiography; D020204:Skull Fracture, Depressed / Q000000981:diagnostic imaging* / Q000473:pathology*; D012887:Skull Fractures / Q000000981:diagnostic imaging* / Q000473:pathology*; D014948:Wounds, Gunshot / Q000473:pathology*
keywords: backface deformation; ballistic injury; biomechanics; forensic science; head injury; helmet deformation