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Myth and Mechanisms of Firearm Injuries

Myth and Mechanisms of Firearm Injuries. Dr. Joel Turner, CCFP, FRCP 3 McGill University January 12, 2000. "A well regulated militia, being necessary to the security of a free state, the right of the people to keep and bear arms, shall not be infringed ”.

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Myth and Mechanisms of Firearm Injuries

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  1. Myth and Mechanisms of Firearm Injuries Dr. Joel Turner, CCFP, FRCP 3 McGill University January 12, 2000

  2. Myths and Mechanisms of Firearm Injuries

  3. "A well regulated militia, being necessary to the security of a free state, the right of the people to keep and bear arms, shall not be infringed” 2d Amendment to the U.S. Constitution Myths and Mechanisms of Firearm Injuries

  4. Myths and Mechanisms of Firearm Injuries

  5. Monday 11 October 1999 Man faces charge in friend's shooting A 21-year-old man is to be charged in connection with a fatal shooting in Notre Dame de Grace early yesterday morning ALLISON LAMPERT . Myths and Mechanisms of Firearm Injuries

  6. Myths and Mechanisms of Firearm Injuries

  7. Objectives: 1. Epidemiology of Firearm-related injuries/deaths 2. Basic anatomy and terminology 3. Ballistics of firearms 4. Role of the EP Myths and Mechanisms of Firearm Injuries

  8. 1. Epidemiology/Statistics Firearm death rate (per 100,000) for young males in 12 selected countries (Center for Disease Control. Births & Death, 1995) Myths and Mechanisms of Firearm Injuries

  9. Year Total firearm deaths Homicides Suicides Accidents Police Misc 1982 33,086 13,841 16,573 1,756 376 540 1993 39,595 18,940 18,571 1,521 1997 32,436 13,623 17,515 981 Just the facts…. • In 1997, -68% of all homicides caused by gun • 92% among young blacks • 86% of all suicides caused by gun • Number of non-fatal GSW ranges from 140,000 to 200,000 / year • 17,000 / year are treated in ED’s for unintentional GSW Voelker R. JAMA, 1995 Hayert, et al. Natl Vital Stat Reports, 1999 Sinauer, et al. JAMA, 1996 Myths and Mechanisms of Firearm Injuries

  10. -Firearms are the 2nd leading cause of death of children in the U.S.  Number 1 cause of death in young blacks Firearms Deaths (per 100,000) by Mode of Death for Children <15 Years of Age - Top 10 Countries C.D.C. Rates of Homicide, Suicide, and firearm- Related death among children. MMWR, 1997 Myths and Mechanisms of Firearm Injuries

  11. Quebec (89-96) Canada (89-96) 1,385 337 66 187 291 1013 17 56 Year Year Total firearm deaths Total firearm deaths Homicides Homicides Suicides Suicides Accidents Accidents Police Police Misc Misc 1982 33,086 13,841 16,573 1,756 376 540 1982 1,530 213 1,197 56 6 58 1993 39,595 18,940 18,571 1,521 1993 1,286 173 1,053 44 5 11 1997 32,436 13,623 17,515 981 1997 1,131 177 881 46 Canadian numbers… United States Canada Myths and Mechanisms of Firearm Injuries (Hurg K, Firearm Statistics. Dept of Justice, March, 1999)

  12. Canadian numbers… (Canadian Firearm Centre- Statistics Canada) Myths and Mechanisms of Firearm Injuries

  13. Canadian numbers… (Canadian Firearm Centre – Angus Reid Group, May 1998) Myths and Mechanisms of Firearm Injuries

  14. Canadian numbers… (Canadian Firearm Centre- Statistics Canada. Homicide Survey, 1997) Myths and Mechanisms of Firearm Injuries

  15. Hospital Visits and admissions 1989-1995: 9,995 people shot in Washington State -29%  ED care only -29%  Admitted to hospital & survived -42%  died (Cummings, et al. Annals of Emergency Medicine, 1998) Canada: 1988-1996: average 1,217 admissions/year Quebec: 1988-1996: average 287 admissions/year (23.6%) 43.6% - firearm accidents 28.2% - self-inflicted 22.0% - inflicted by others (Canadian Institute for Health Information) Myths and Mechanisms of Firearm Injuries

  16. 2. Terminology & Anatomy of Firearms A. The Gun: Myths and Mechanisms of Firearm Injuries

  17. Anatomy of the Gun Action Muzzle Chamber Barrel Hammer Magazine (Clip) Bore Caliber Rifling Myths and Mechanisms of Firearm Injuries

  18. The Guns • Handguns • Single shot weapons (target pistol) • Derringer • Revolver • Semi-automatic pistol 2. Rifles 3. Shotguns 4. Fully automatic Myths and Mechanisms of Firearm Injuries

  19. The derringer Myths and Mechanisms of Firearm Injuries

  20. The Revolver Myths and Mechanisms of Firearm Injuries

  21. Semi-automatic pistol Myths and Mechanisms of Firearm Injuries

  22. Rifles Myths and Mechanisms of Firearm Injuries

  23. Shotguns Myths and Mechanisms of Firearm Injuries

  24. Anatomy of the Cartridge Shot bullet Wad Powder Flash Hole Powder Primer Primer Shotgun Rifle Handgun Myths and Mechanisms of Firearm Injuries

  25. Some Powder basics: Small arms powder made of: 1. Nitrocellulose base, or 2. Nitrocellulose / nitroglycerine mix -Smokeless powder is NOT an explosive (black powder IS) -Grains come in different shapes and sizes -The smaller the grain the faster it burns Myths and Mechanisms of Firearm Injuries

  26. Myths and Mechanisms of Firearm Injuries

  27. 3. Ballistics of firearms. • Science of travel of projectile in flight • Divided into 3 parts: • Internal (travel within the gun) • External (gun to target) • Terminal (wound ballistics) Myths and Mechanisms of Firearm Injuries

  28. I. Internal Ballistics – what affects what? BANG! (what happens when the trigger is pulled?) • Primer fires • Intense flame created by primer fills chamber • Powder burns, creates large gas expansion • Huge pressure generated pushes bullet • -The more complete and instant the burning, • the more efficient the expansion of gas • The tighter the hold of the bullet in the cartridge, • The tighter the fit in the bore, •  the more efficient use of the gas Myths and Mechanisms of Firearm Injuries

  29. I. Internal Ballistics – what affects what? A little bit of physics… Myths and Mechanisms of Firearm Injuries

  30. II. External Ballistics – gun to target Myths and Mechanisms of Firearm Injuries

  31. II. External Ballistics – gun to target Myths and Mechanisms of Firearm Injuries

  32. III. Terminal Ballistics – Wound Ballistics What happens when the bullet hits the target? Myths and Mechanisms of Firearm Injuries

  33. III. Terminal Ballistics – Wound Ballistics Bullets produce damage in 3 ways: 1. Laceration and crushing 2. Cavitation: a) permanent cavity: b) temporary cavity. (tissue splash) 3. (Shock waves) (U.S. Dept of Defense) Myths and Mechanisms of Firearm Injuries

  34. IV. Wounding mechanisms – Wound Profiles • Many tissue simulants have been tried, few are accurate • (eg: animals, clay, soap, water-soaked phone books...). • Valid tissue simulant – 10% Ordnance Gelatin • Calibrated against various living animal tissue • Shots into this substance  wound profiles • Accuracy verified by comparing with human autopsies. • Now: Scientifically valid measurement tool • Different projectile effects can be compared. • Principles of wound ballistics can be studied. • Can predict wounding potential of various projectiles. Fackler, et al. J Trauma. 1985 Fackler, et al. Wound Ballistics Review. 1994 Myths and Mechanisms of Firearm Injuries

  35. IV. Wounding mechanisms – Wound Profiles A. Handguns and Rifles Neck .32 Cal. Silvertip Winchester -soft lead -Non-fragmenting, expanding -Velocity: 940 fps (similar to present day .22 cal) Fackler, et al. Annals of Emergency Medicine. 1996 Myths and Mechanisms of Firearm Injuries

  36. IV. Wounding mechanisms – Wound Profiles M-80 7.62 mm NATO cartridge: -Full Metal Jacket -Non-fragmenting, Non-expanding -Velocity = 2800 fps Myths and Mechanisms of Firearm Injuries

  37. IV. Wounding mechanisms – Wound Profiles Mannlicher Carcano 6.5 mm -Full metal Jacket -Non-deforming, Non-fragmenting -Velocity = 2085 fps Myths and Mechanisms of Firearm Injuries

  38. IV. Wounding mechanisms – Wound Profiles .45 Cal Automatic pistol - full metal jacket - velocity = 870 fps Myths and Mechanisms of Firearm Injuries

  39. IV. Wounding mechanisms – Wound Profiles M-16 .22 Cal Military Rifle -Full Metal Jacket -Fragmenting rifle bullet -Velocity = 3035 fps Myths and Mechanisms of Firearm Injuries

  40. IV. Wounding mechanisms – Wound Profiles Winchester .308 Caliber Hunting Rifle (civilian) -civilian equivalent of military M-16 -Soft Point bullet -Fragmenting bullet -Velocity = 2,900 fps Myths and Mechanisms of Firearm Injuries

  41. IV. Wounding mechanisms – Wound Profiles B. Shotguns 12 gauge shotgun - 1 oz slug - Velocity = 1510 fps Myths and Mechanisms of Firearm Injuries

  42. IV. Wounding mechanisms – Wound Profiles 12 gauge shotgun - 27 pellet #4 buck shot - Velocity = 1350 fps Myths and Mechanisms of Firearm Injuries

  43. IV. Wounding mechanisms – Wound Profiles 12 gauge Shotgun -169 pellets, #4 shot - Velocity = 1200 fps (Letterman Army Institute of Research) Myths and Mechanisms of Firearm Injuries

  44. IV. Wounding mechanisms – Wound Profiles Myths and Mechanisms of Firearm Injuries

  45. V. Myths of Firearm Injuries and Wound Ballistics: a) Myth of High Velocity: False dogma: 1. Tissue damage is directly related to bullet velocity. 2. High vel. missile injuries require aggressive resection. 3. Low vel. missile injuires require little or no treatment. 1960’s – Vietnam war, introduction of M-16 rifle (bullet speed = 3100 fps): - GSW severity increased significantly - The M-16: “massively destructive” “devastating wounding power” - High velocity became synonymous with “devastating killing power” Rich, et al. JAMA. 1967 Dimond, et al. J Trauma. 1967 Myths and Mechanisms of Firearm Injuries

  46. V. Myths of Firearm Injuries and Wound Ballistics: a) Myth of High Velocity…. 1974 – Rybeck, et al. - High vel. Injuries cause temporary cavity 30x diameter of missile. - this tissue “would not survive” -  core of tissue would have to be excised!! -  equates to an amputation of almost any wound to arm/leg Rybeck, et al. Acta Chir Scand. 1974 1975 -The Nato Handbook: Emergency War surgery (U.S. Govt. Printing Office) Myths and Mechanisms of Firearm Injuries

  47. V. Myths of Firearm Injuries and Wound Ballistics: BUT: History of small arms development shows us differently: -Late 1880’s  largest increase in vel. of small arms projectiles. - From 1,100 to 2,400 fps - Invention of smokeless gun powder and jacketed bullets - striking decrease in wounds severity reported from all battlefields !! Myths and Mechanisms of Firearm Injuries

  48. V. Myths of Firearm Injuries and Wound Ballistics: .38 Special Velocity = 880 fps Remington .357 Magnum Velocity = 1400 fps  Despite the 60% increase in velocity, the shape and size of both temporary and permanent cavities are very similar, Fackler, Emergency Medicine Clinics of North America. 1998 Myths and Mechanisms of Firearm Injuries

  49. V. Myths of Firearm Injuries and Wound Ballistics: M80 7.62 mm NATA cartridge Velocity = 2800 fps M-16 .22 Cal Military Rifle Velocity = 3035 fps •  Despite similar velocities, M-16 produces significantly more injury. • Bullet fragmentation is predominant reason for M-16’s increased tissue disruption Fackler, Emergency Medicine Clinics of North America. 1998 Myths and Mechanisms of Firearm Injuries

  50. V. Myths of Firearm Injuries and Wound Ballistics: b) Shock waves and Injury 1940’s: Harvey, et al. Surgery. 1947 1980’s: Suneson, et al. J Trauma. 1987, 1988, 1989 1990’s: Ordog, et al. J Trauma. 1994 Present day lithotriptor: Myths and Mechanisms of Firearm Injuries

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