Weapons Effects

Overview

• Epidemiology of Injuries• Mechanism of Injury• Antipersonnel Landmines• Small Arms

Epidemiology of Injuries

• Two Major Categories of Weapons– Explosives: artillery, grenades, mortars, bombs,

hand grenades– Small Arms Fire: pistols, rifles, machine guns

• Most common pattern or injury is multiple small fragment wounds of extremities

Mechanism of Injury: Projectiles

• There are two areas of projectile-tissue interaction– Permanent cavity: localized area of tissue injury that is proportional to

the size of the projectile

• Temporary cavity: Transient displacement of tissue, which occurs after passage of the projectile. – Elastic tissue, such as skeletal muscle, blood vessels and skin, may be

pushed aside after passage of the projectile, but then rebound. – Inelastic tissue, such as bone or liver, may fracture in this area.

Mechanism of Injuries: Explosives

• Explosives have three mechanisms of injury:– Ballistic– Blast– Thermal

Mechanism of Injury

• Ballistic: – Injuries caused by fragments created by explosives– Typically cause multiple wounds

• Blast– This occurs more closely to the explosion compared to ballistic injury– The ears are most often affected by the overpressure, followed by lungs and

gastrointestinal organs. – The explosion creates a blast wind that can throw victims against solid objects,

causing blunt trauma.

• Thermal– The result of combustion, may cause burns

Antipersonnel Landmines

• Tree types of antipersonnel landmines– Static– Bounding– Horizontal spray

Antipersonnel Landmines

• Static: small landmines that detonate when stepped on and result in 2 types of injury• Partial or complete traumatic amputation• More proximally, tissue and other debris is pushed up

along fascial planes, stripping tissue from bone

Antipersonnel Landmines

• Bounding: a mine that is propelled to 1-2m in height and then explodes, causing multiple small fragment wounds. This type of mine is associated with the highest mortality.

• Horizontal spray mines: propel fragments in one direction, causing multiple small fragment wounds

Small Arms

• In the past, differentiation made between HI and LOW velocity weapons but now felt not to be totally different entities.

• Change to higher velocity weapons a result of change to smaller and lighter automatic weapons

• Automatic weapons more effectiveMost combat actions < 200 metersMost infantry not great marksman

• Smaller, lighter ammo developedLess recoil, better aimEach soldier can can carry more rounds

• To maintain wounding power, higher bullet velocities were necessary

• Higher velocities developed to increase FIREPOWER, not wounding power (same)

• Always potential for higher energy transfer with higher velocity, but this is not always the case

• Surgeon should always be concerned with the individual wound, rather than the “worst case scenario”

Small Arms (cont)

• Some missiles are designed to fragment or expandDum-dums, Hollow-points, Non-jacketed, Some fragments despite copper jacket (M-16)

• Fragments cause multiple tracts of permanent and temporary cavities

• Expansion makes the permanent cavity wider

Fragmentation/ Expansion

Yaw

• Yaw is the deviation in the longitudinal axis of the bullet from its line of flight (tumbling)

• Yaw is usually 180 degrees and can be caused by striking foliage or tissue

• It increases the area of permanent and temporary cavitation

• Important in the injuries caused by AK-47, AK-74

Shotgun Injuries

Shotgun shells have a big powder charge with a large mass of lead balls

• Destructive potential depends on range

• At close range, it can cause a large wound with severe disruption of anatomy by direct crush alone

• Long range (>25m) cause usually only skin wounds

• Wadding is a projectile too