The risk of penetrating trauma is important to assess due to the increase in severity of injuries seen once the munition penetrates into the body cavity. One factor to consider is the amount of energy generated by the munition. In addition, it is important to determine the energy per area of presentation ratio or E/a value. This value takes into account the mass, velocity, and the cross-sectional area of the projectile. Simply reporting energy is insufficient for comparison of different samples and projectiles. The penetration assessment surrogate is composed of 20% ballistic gelatin, foam, and natural chamois.
The risk of blunt trauma to the thorax has been assessed by using an empirically based injury criterion called the viscous criterion (VC). This criterion has used extensively for motor vehicle occupants to predict the severity of injury. The VC is calculated based on the amount of thoracic compression and the velocity at which this compression occurs. The amount of thoracic compression was defined as the displacement of the chest in relationship to the spine normalized by the initial thickness of the thorax. VC has been validated as a useful tool in determining injury severity related to blunt ballistic impacts to the thorax. Blunt trauma assessment of less-lethal munitions is conducted at Wayne State University with the 3-RBID ballistic impact surrogate.
