Improvised explosive devices (IED) have added a new dimension to
battlefield injuries: wounds and even deaths
among troops who have no external
signs of trauma, but whose brains have been severely damaged.
The detonation of any powerful explosive generates a blast wave
of high pressure that spreads out at 1,600 feet per second from the
point of explosion and travels hundreds of yards. The lethal blast
wave is a two-part assault that rattles the brain against the
skull. The initial shock wave of very high pressure is followed
closely by the "secondary wind:" a huge volume of displaced air
flooding back into the area, again, under high pressure. No helmet
or armor can defend against such a massive wave front.
Excerpt of report by Brandon Keim