FORENSIC PATHOLOGY

1. FORENSIC PATHOLOGY GUNSHOT WOUNDS

2. GUNSHOT WOUNDS • GSW are penetrating or perforating • Penetrating = bullet enters an object but does not exit • Perforating = bullet passes through and exits object

3. GUNSHOT WOUNDS • Many things follow the bullet upon leaving the barrel • Partially burned powder • Particles of bullet metal • Soot • Bullet lubricant • Inorganic elements from primer

4. GUNSHOT WOUNDS • Gunpowder exits the muzzle in two forms • Completely burned powder is called soot or fowling • Burning and unburned particles are referred to as stippling or powdered tattooing • Particles will travel farther than the soot and will abrade the skin

6. GUNSHOT WOUNDS • Soot • Carbon powder which contains vaporized metals from primer, bullet and cartridge case • As range from muzzle to target increases, size of zone of powder soot blackening will increase • Density of blackened soot decreases

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8. GUNSHOT WOUNDS • Placement of soot can vary due to • Range • Propellant • Angle of muzzle to target • Barrel length • Caliber of weapon • Type of weapon • Target material and state of target (blood or not)

9. Soot Barrel length Longer barrel produces smaller and more dense soot patterns Handguns deposit soot out to 30 cm Orientation of muzzle Muzzle at 90 degree angle = circular shape with hole in center Muzzle at 2cm + angle = blossom shape with eccentric hole GUNSHOT WOUNDS

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11. GUNSHOT WOUNDS • Gunshot Wound Residue is deposited in zones • Zone I = Contact GSW • Muzzle of weapon held against body surface • Wound may be classified as hard, loose, angled or incomplete • Edges may be seared by gases and blackened by soot and propellant • With or without seared blackened zone around wound

12. GUNSHOT WOUNDS • Zone I - Hard Contact Wounds • Muzzle of weapon is jammed “hard” against skin • Outside line of certain parts of the firearm may be imprinted in the skin • Barrel, front sights • Skin is indented by weapon • Edges of wound are seared by hot gases of combusted and blackened soot • Soot may be embedded in seared skin • Cannot wash soot out of wound

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16. GUNSHOT WOUNDS • Zone II – Loose • approx. 0- 4 inches away from body • Intense, dark sooting with dense deposits of unburned and partially burned powder around bullet hole • Destruction of clothing and skin possible

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18. GUNSHOT WOUNDS • Zone II = Loose Contact • Muzzle in contact with skin, but held lightly against surface • Gas from weapon forms gap between gun and wound • Soot is deposited around entrance wound • Soot can be wiped away

19. GUNSHOT WOUNDS • Zone II = Angled Contact Wound • Muzzle is held at an angle to the skin • Gas and soot radiate outward from muzzle • Soot is found in two different zones • Most noticeable zone – Blackened seared area of skin or cloth, having a pear, circular or oval shape • Second zone – large fan-shaped zone of light gray soot radiating from gap • Soot can be washed away

20. GUNSHOT WOUNDS • Zone II – Angled Contact Wounds • Eccentric seared blackened zone of skin on opposite side of wound from muzzle pointing the way the gun was directed • Wound widest on side opposite muzzle • Larger eccentric zone of soot deposition

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22. GUNSHOT WOUNDS • Zone II – Angled Contact Wounds • If the angle between the barrel and skin decreases, the gap between muzzle and skin is larger • More material can escape through the gap • Unburned grains of powder may sear skin • Angled contact wounds can have powder tattooing on opposite side of wound from muzzle

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25. GUNSHOT WOUNDS • Zone II – Incomplete Contact Wounds • Muzzle of weapon is held against the skin, there is a gap between muzzle and skin • Soot escapes through gap • Seared or blackened skin located adjacent to wound • Most often seen in suicides

26. GUNSHOT WOUNDS • Zone III – Near • Approximately 4 – 6 inches from body • Medium to light gray sooting • Circular pattern of powder distribution around bullet hole • Tattooing possible

27. GUNSHOT WOUNDS • Zone IV – Intermediate Range Wounds • Approximately 6 – 24 inches from body • No visible sooting • Dispersed powder particles • As soon as one sees individual tattooing marks, one is dealing with intermediate range wounds • Near wounds may be seared zone, but no individual tattoo marks

28. GUNSHOT WOUNDS • Zone IV – Intermediate • Tattooing • Reddish-brown to orange-red punctate lesions around wound entrance • Skin on same side of barrel (at angle) will have dense tattooing • Powder tattooing occurs antemortem • Postmortem tattooing marks are gray or yellow in color

29. GUNSHOT WOUNDS • Zone IV – Intermediate Range Wounds • Powder tattooing is due to impact of powder grains on skin – Not powder burns • Punctate abrasions cannot be wiped away

30. GUNSHOT WOUNDS • Zone V: Distant Range Wounds • Approximately 2-3 feet or greater • The only marks on the body are those produced by mechanical action of bullet perforating the skin

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37. GUNSHOT WOUNDS • Revolvers • Gas, soot and powder emerge from muzzle and gap between cylinder and barrel • If weapon is parallel to body soot from cylinder-barrel gap produces a L- or V-shaped pattern • If weapon is at an acute angel to body, searing will occur a distance from entrance wound • Can measure barrel length

38. GUNSHOT WOUNDS • Muzzle Brake • Redirects gases at muzzle to generate a forward thrust on muzzle and counters force of recoil • Flash Suppressor • Breaks up the “fireball” • Cylinder with longitudinal slits along its length • Gases emerges through the slits instead of out muzzle