Traumatic Brian Injury (TBI) is generally caused by the head striking a solid surface. Frequently, a large number of TBIs can be attributed to motor vehicle accidents. For the past decade or so, TBI has also been tracked as a concerning injury among the military. There have been organizations whose primary goal has been helping to inform people about TBI.
Getting solid numbers on the true numbers of TBI is difficult. For the military, it is a little bit easier to get a better idea of the numbers. Estimates are between 200 and 400 thousand generally agreed upon documented cases of TBI. The majority of TBIs are categorized as mild TBI–indicating that consciousness was not lost for more than 5 minutes or so.
Other categories of TBI are the moderate and severe forms of closed head injury. The military has more experience with penetrating head injuries than do many civilian facilities. Congresswoman Gabby Giffords was shot in the head and thankfully she was able to be rushed away to get treatment. She suffered what is termed a through and through penetrating head injury.