Effect on Tissues
Two types of pressure waves are generated by the interaction of the blast wave with the body:
Stress waves are longitudinal forces moving at supersonic speeds which create spalling effects at tissue-gas interfaces [1,7].
This is where the shock wave travelling through a tissue reaches an interface with a tissue of lower density (such as gas) and creates a negative reflection at that interface causing fragmentation of the surface of the higher density tissue. This results in microvascular damage [3].
Stress waves also cause implosion of gas-containing structures such as bowel or alveoli by the higher-pressure tissues surrounding them. Blood is forced into the gas-filled compartments by the pressure differential across these interfaces [3].
Shear waves are longer duration and lower velocity transverse pressure waves that result from differences between the rates of acceleration and deceleration of tissues with different densities, in response to the blast waves.
These shear forces result in the tearing of tissues and organs and may result in injury to their attachments [1].