A traumatic brain injury (TBI) refers to a brain injury that is caused by an outside force. TBI can be caused by a forceful bump, blow, or jolt to the head or body, or from an object entering the brain. Not all blows or jolts to the head result in TBI.
Some types of TBI can cause temporary or short-term problems with brain function, including problems with how a person thinks, understands, moves, communicates, and acts. More serious TBI can lead to severe and permanent disability, and even death.
Some injuries are considered primary, meaning the damage is immediate. Others can be secondary, meaning they can occur gradually over the course of hours, days, or weeks after injury. These secondary brain injuries are the result of reactive processes that occur after the initial head trauma.
There are two broad types of head injuries: Penetrating and non-penetrating.
Penetrating TBI (also known as open TBI) happens when an object pierces the skull (e.g., a bullet, shrapnel, bone fragment, etc.) and enters the brain tissue. Penetrating TBI typically damages only part of the brain.
Non-penetrating TBI (also known as closed head injury or blunt TBI) is caused by an external force strong enough to move the brain within the skull. Causes include falls, motor vehicle crashes, sports injuries, blast injury, or being struck by an object.