According to the Centers for Disease Control and Prevention, approximately 14% of all traumatic brain injuries result from motor vehicle accidents. A TBI can range from mild to severe.
There are several different types of brain injuries and different ways of categorizing them.
Primary versus secondary
A primary TBI is damage to the brain that occurs as a direct result of the trauma. According to the Model Systems Knowledge Translation Center, examples of primary TBIs include diffuse axonal injury and localized damage to a particular part of the brain. A skull fracture can also result in a primary TBI.
A secondary TBI occurs as a consequence of the primary injury, usually within a few days of its occurrence. For example, brain tissue swelling can cause increased pressure inside the skull, which can cut off oxygen to the brain and cause a secondary injury.
The goal of the physician treating someone with a TBI from a car accident is to prevent secondary injuries because there is no way of reversing a primary TBI.
Open versus closed
An open head injury is one that exposes the brain to air because of penetration of the skull and other protective layers by a foreign object. For example, if a car crash were to force a sharp object into the skull, that would be an example of an open head injury. In a closed head injury, there is no penetration of the skull and no exposure of the brain to the open air.
Closed head injuries can result in severe TBIs just as open ones can. Whether the injury is open or closed has no bearing on how serious it is.