22 - Firearm Injuries Part1

7/31/2019 22 - Firearm Injuries Part1

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By:Nour Abu Al Shaar

FirearmInjuries


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Some terminologyBarrel: the metal tube through which

the bullet is fired.Bore: the inside of the barrel, either:

Smooth bore: Shotguns.

Not smooth bore: rifles, pistols.


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Muzzle: the end of the barrel out ofwhich the bullet comes out.

Primer: volatile substance thatignites when struck to detonate the

powder in a cartridge.


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The holder presses the firing pinwhich in turn strikes the primerwhich ignites the powder and

produces large amount of hot gas.Produces very high pressure that fires

the bullet forcefully through the

barrel leaving the muzzle, and ontothe target.

What

happens?


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Mechanism of injury:

As the missile traverses the body it causesinjury by:

1. Basic contact of bullet and its fragments (ifpresent) with the tissue, so larger bulletscreate bigger damage at the same velocity.

2.Transferring some of its available kineticenergy to the tissue around it, so increasingvelocity greatly increases damage.

3. It also causes cavitations in the tissue itpasses as it accelerates molecules makesthem move centrifugally away from the axisof the bullet.

Bullets do not typically follow a straight line


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Mode of injury depends on the velocityof the missile

-Slow velocity (


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Short Long

Types of firearm weapons


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Types of firearmweaponsNon-rifled: only long

Rifled: short and long


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Smooth bore weapon(Shotgun):

A gun with a smoothbore that shootscartridges that contain "shot" or smallmetal pellets (of lead or steel) as theprojectiles.

Ammunition: A shotgun shell(cartridge)may contain one large projectile (called aslug), a few pellets of large shot, or manytiny pellets. Cartridge made of a cylinderfitted into a metal base contains charge

of propellant, wads, and shots.Rangeis the most important factor, andcan be estimated in over half of casesClose range wounds are severe, but ateven relatively short distances, wounding

may be minimal.


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Non-rifled weapons

Types of missiles


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Look for any wads inthe tissues beforeclosing the woundto prevent possible

infectionso notjust the

bullets/pellets.


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The rifle weapon:

Rifles differ from shotguns in thelength of the barrel and the presenceof a butt stock.

They fire one projectile at a timethrough a thicker barrel that hasspiral grooves on its inner surface rotational movement.

They are much more accurate andshoot more powerful cartridges thanhandguns.

Ammunition: metal cylinder loaded

Rifl


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Riflebullet/pistol

bullet


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Extras

Solid organs such as the brain and theliver are affected more than thespongy lung.

In most of the shooting cases seen byforensic pathologist death will haveoccurred rapidly, however when it isdelayed secondary damage frominfarction, local necrosis of musclesand organs, and infections mustalways be kept in mind.

Modern propellants consist ofnitrocellulose which ischaracteristically colored and found in


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Characters of firearminjuries 1- Loss of substance

2- Presence of inlet and/or exit

3- Powder marks

4- Beveling of flat bones


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Suicide and Homicide:

Suicide:must show wounds whose range is within the arm's

reach the weapon must be present.

Suicides shoot themselves in sites of election whichcompromise the mouth, the front of the neck, the

forehead, the temples and the front of the chest.Homicide:Multiple firearm wounds suggest homicide.Inaccessible part of the body.Wounds outside the range of arms reach.

People almost never shoot themselves in the eyes orat the back, and women rarely commit suicide withguns; so a shot woman is a murdered woman untilproven other wise.


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22 - Firearm Injuries Part1

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