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 effective Most combat actions < 200 meters Most infantry not great marksman Smaller, lighter ammo developed Less recoil, better aim Each 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 expand Dum-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