Abstract
Despite years of effort to prevent traumatic brain injuries (TBIs), the occurrence
of TBI in the United States alone has reached epidemic proportions. When an external
force is applied to the head, it is converted into stresses that must be absorbed
into the brain or redirected by a helmet or other protective equipment. Complex interactions
of the head, neck, and jaw kinematics result in strains in the brain. Even relatively
mild mechanical trauma to these tissues can initiate a neurochemical cascade that
leads to TBI. Civilians and warfighters can experience head injuries in both combat
and noncombat situations from a variety of threats, including ballistic and blunt
impact, acceleration, and blast. It is critical to understand the physics created
by these threats to develop meaningful improvements to clinical care, injury prevention,
and mitigation. Here the authors review the current state of understanding of the
complex loading conditions that lead to TBI and characterize how these loads are transmitted
through soft tissue, the skull and into the brain, resulting in TBI. In addition,
gaps in knowledge and injury thresholds are reviewed, as these must be addressed to
better design strategies that reduce TBI incidence and severity.
Keywords
traumatic brain injury - blunt trauma - blast - ballistic - physics - acceleration
- diffuse axonal injury
