Incidence of head injuries attributable to rotation

Head injuries continue to be one of the most frequent and debilitating consequences of automobile crashes. Each year in the United States, about 35,000 motorists suffer a head injury of AIS 3 or greater in a crash. About 12,000 of these victims die. The side impact crash mode appears to be the greatest source of head injuries, with an estimated 26% of the total. The incidence and nature of head injuries sustained in crashes is the subject herein. All possible brain injuries and skull fractures are denoted by 229 unique codes as described in the AIS Injury Coding Manual. It is assumed that these injuries may be placed into three broad categories: those manifested by rotation only (such as diffuse axonal injuries), those manifested by translation only (such as skull fractures), and those manifested by either rotation or translation. Upon categorizing each code into one of the three categories, NASS-CDS data may be interrogated to gain insights into the various types of head injuries. About 16% of motorists with head wounds have injuries deemed to be attributable to rotational effects only; another 16% have injuries attributable to translational effects only. About 29% incur both types of head injuries, and the rest (about 39%) have injuries that may be attributed to either translation or rotation. When one considers fatalities only, an estimated 842 deaths per year are attributable to rotationally-induced brain injuries. Such results highlight the need for a rotation-based anthropomorphic dummy metric to gauge head injury potential in crash tests.