Sławomir Majdanik Firearm injuries Department of the Forensic Medicine Pomeranian Academy of Medicine of Szczecin

Definition many kinds of weapons may cause firearm injury: shotguns /used by hunters/ handguns (pistols or revolvers) rifles home - made guns / `country guns`/ air rifles sports guns

Definition Rarely firearm injuries are caused using other kinds of objects: projectiles and their fragments (artillery shells, mortars) captive - bolt guns industrial stud-guns alarm guns /tracer shells/

Gun muzzle barrel trigger gunlock cock

Cartridge Projectile Gunpowder Cartridge case Primer

Shotgun ammunition Wad Gunpowder and shot Cardboard or plastic cylinder Metal base including primer

Calibre 7.62 mm and 9 mm are most frequent calibres in Poland. barrel (cross section) calibre

Basic factors affect nature of a gunshot wound type of weapon missile velocity nature of projectile range of discharge angle of discharge

Why firearms injuries are often fatal ? Because of significant kinetic energy of the bullet. V o = m/s (even more !) E k = m V 2 2

Gunshot injuries I. Gunshot injury penetrate through the head (or leg, arm, neck, trunk...) a/ entrance wound b/ canal of the shot c/ exit wound

Gunshot injuries II. “blind” shots - bullet is lodged in the victim`s body a/ entrance wound b/ canal of the shot c/ bullet in the body

“Migrating bullet” bullet when lodged in the vessel may move /up or down the blood flow/ in the victim`s body

“Migrating bullet” bullet when lodged in a cavity may move /following the gravitation force/ in the victim`s body

Gunshot injuries III. Diagonal gunshot injury /wound or abrasion/

Gunshot injuries IV. Ricochet (bullet changes trajectory) Nevertheless non typical serious injuries may occur lower velocity of the bullet

Gunpowder comes out the muzzle in two forms: Completely burned gunpowder, called “soot” or “fouling”, can be washed off the skin. Particles of burned and unburned powder can become embedded in the skin or bounce off and abrade the skin. The marks on the skin are called “tattooing” or “stippling”.

Analysis of the gunpowder traces A. microscope determination (including electron microscopy) B. chemical determination 1. Wellenstein-Kober reaction (green-blue tint) 2. “parch” reaction /in high temp./ 3. Griess&Illosvay reaction (pink tint)

Entrance wound (right angle) Central defect Soiled area (lubricant & soot & metal fragments) Rim of abrasion [width=1-3mm] (effect of the shock wave) Stippling/tattooing & soot/fouling area (burned gunpowder and gunpowder particles) Shot direction 

Entrance wound (acute angle) Shot direction 

Canal of the wound Fragments of clothing Fragments of bullet/shot Fragments of bone /other tissue/

Exit wound Central defect soiled area (none) rim of abrasion (none) gunpowder and its traces (none)

Gunshot (tight contact and loose contact) barrel tight contact skin muzzle loose contact

Gunshot (tight contact) all gunpowder residue on the edges or inside a wound there may be searing or burning of wound margins barrel victim

Gunshot (tight contact) reddening of surrounding margins may occur due to CO gas produced by burning powder (Paltauf sign) barrel victim

Gunshot (tight contact) muzzle impression (muzzle mark on skin) barrel victim

Gunshot (tight contact) There is often tearing of the skin around the entrance wound (specially in head wounds) because of pressure build-up and blow-back of the skin toward the muzzle barrel victim

Gunshot (loose contact) muzzle impression ( - ) gunpowder may escape from the barrel and be deposited around the edges of a wound barrel victim

Gunshot (close range) fouling and stippling are present barrel victim

Gunshot (intermediate range) fouling ( - ) stippling is present barrel victim < 1 m

Gunshot (distant range) fouling ( - ) stippling ( - ) victim > 1 m

Shotgun wound /caused by shot/ or contact wounds “rat hole” wound (from 30cm to 1 metre)

Shotgun wound /caused by shot/ Satellite pellet holes (appearing at the distance of over 1 metre) Spread of shot increases, central hole diminishes Uniform spread with no central hole (appearing at the distance of over 10 metres)

Scene 1. The scene must be examined for bullets and cartridges. 2. Localisation of the body and the gun must be considered. 3. Traces on the wearing and victims hands must be protected !

Autopsy examination in the case of gunshot 1. Inspection of the victim`s clothing (gun powder traces, damage) 2. Localisation and inspection of the entrance/exit wound 3. Inspection of the canal of the wound 4. Finding the bullet

Commonly asked question I. How close was the victim to the gun when it was fired ? II. What was the the trajectory in the body ? (where is the entrance/exit wound ?) III What was the calibre /kind/ of the gun ? IV. What was the sequence of the gunshot ?

Most important question is...

homicide? suicide? accident?

A typical hunting accident “I swear it was a wild boar”

Captive - bolt guns /to dispatch large animals/ Metal rod is propelled for about 5 centimetres from the muzzle. Captive bolt inflicts a clean, penetrating injury, which can be mistaken with stab-like injury. skin muzzle

Industrial “stud-guns” Specific piston acts as a hammer on the metal pin or stud. skin/wall muzzle

Rubber and plastic bullets To disperse riot Velocity about 250 kph Effective range 50-70m

Death from explosion Both civilian and military circumstances

Death from explosion - mechanisms a/ blast effect b/ impact of projectiles originating from the explosives device c/ impact from surrounding objects and debris impelled by the explosion d/ burns from hot gas and incandescent objects

Death from explosion - injuries “Peppering” by numerous small missiles causing lacerations and bruises. Burning. A bomb can totally fragment the body and scatter unidentifiable pieces over a large area.