Comparison of the Distribution of Cranial Fractures by Mechanism of Formation

Abstract

Different mechanisms can cause bone fractures. This retrospective study considers whether the distribution of cranial fractures can help distinguish the mechanism by which fractures formed. Data are from two sources: cases of motor vehicle collision (MVC) and fire-related deaths obtained from the Jefferson County Coroner/Medical Examiner (JCC/MEO) archives and information on fatal MVCs from the National Automotive Sampling System Crashworthiness Data System (NASS/CDS). In review of the JCC/MEO archives, cranial fractures were documented in 30% of MVC deaths. Fractures were restricted to the base of the skull in 45% of those cases, involved both base and cranial vault in 53%, and was confined to the cranial vault in 2.6%. Cranial fractures were documented in only 4% of deaths involving fire. The NASS/CDS data (n=31 911) are similar, with fracture involving only the base of the skull in 40.9% of cases, both base and vault in 42.3% of cases, and vault only in 16.8% of cases. Cranial fractures in fire-related MVCs vs. non-fire MVCs were more likely to involve the vault only (31.5% vs. 16.9%) and less likely to involve the base and vault (36.4% vs. 45.0%) or base only (32.1% vs. 38.1%). In conclusion, most (>90%) cranial fractures related to MVCs involved the base of the skull. Few deaths only associated with fire were associated with cranial fracture (4%). In circumstances where alternate mechanisms for fracture exist, such as a vehicle catching fire after a collision, fracture of the base of the skull supports the collision as the likely mechanism of fracture.