There are multiple ways in which a traumatic head injury could occur. Assaults, falls and motor vehicle accidents are just three of the situations that could cause it. The term head injury is one that people likely hear a lot. This is unsurprising when one considers just how many types of injuries it includes. When someone talks about a traumatic head injury it is likely that it one of four common types: scalp wound, concussion, open injury or closed injury.
http://www.gluckstein.com/blog/2015/08/information-about-common-types-of-head-injuries.shtml