There are a number of physical events that can result in trauma to the brain, though the most common cause of brain trauma involves a direct blow to the head. The impact and location of the blow often plays a direct role in the severity of the injury. Falling is the most common, and sometimes least severe, source of brain trauma. However, while falling out of bed at night may not result in serious trauma, a slip in the shower or tripping down a flight of stairs can lead to severe injury. A fall can also occur while playing a sport, like soccer or football, though brain injuries incurred during high-impact sports like these are documented apart from normal falls.
About 20 percent of traumatic brain injuries can be directly attributed to some form of violence. Violence can range from shaken baby syndrome to a gunshot wound. Car accidents and other vehicle-related injuries, considered separate from general violence as a source of trauma, can result in traumatic brain injuries for drivers, cyclists, and pedestrians.
Finally, individuals serving in the military are often put at risk for traumatic brain injury. In addition to facing physical violence on a regular basis, many military personnel in combat situations are subjected to explosive blasts. The pressure waves created by such explosions are thought to cause significant disturbances within the brain.