Primary injury is produced solely from the pressure differences within tissues. Injuries typically occur in those areas of the body where an air-tissue interface is found (e.g., the lungs, gastrointestinal tract and ear).
Secondary injury is caused when objects displaced by the detonation strike the body. This can produce a combination of blunt and penetrating trauma.
Tertiary injury occurs when a body is physically propelled against other objects or crush injuries, such as when a body becomes entrapped in a structural collapse or vehicle.
Quaternary injury is related to the environmental factors associated with an explosion, including burns, exposures to toxic by-products or contamination.
Quinary injury describes cases in which inexplicable hemodynamic instability occurs in patients through other explosion-related phenomena. The Department of Defense also relates this injury to the intentional inclusion of physical or biological contaminants to an intended explosive device.
