Primary Blast Injuries are injuries caused by what mechanism?

• A. Debris and shrapnel
• B. Heat and flame
• C. An explosive shock wave
• D. Toxic inhalation

Answer: (C)

Primary blast injuries come from the blast overpressure—the explosive shock wave that propagates through air and into the body. This sudden, high-pressure pulse pushes on tissues and air-filled organs, often damaging the lungs and ears first and sometimes causing brain effects from the rapid pressure change. It’s the pressure wave itself, not contact with debris or heat, that defines primary blast injuries. Debris and shrapnel cause secondary injuries when objects fly into the body; heat and flame cause burns or inhalation injuries as quaternary effects; toxic inhalation can occur from fumes or chemicals. So the explosive shock wave is the mechanism behind primary blast injuries.