Shaped charges and explosively formed penetrators: background for clinicians.

Shaped Charges (SC) have been used in High Explosive Anti-Tank (HEAT) munitions and the mining industry since World War II. An explosive is used to propel a liner material of low mass at speeds in excess of 5 times the speed of sound. The subsequent projectile is capable of penetrating the steel of armoured vehicles and inflicting significant injury to any enclosed personnel. Explosively Formed Penetrators (EFP) are a variant of a SC, using higher mass at lower speed to deliver their kinetic energy. The Iraq conflict has seen the use of Improvised Explosive Devices utilising EFP (IED-EFP) by insurgent groups attacking military vehicles. The major wounding mechanisms are from fragmentation and burns. This article is a brief overview of the history and science behind SC and EFP.