Using Coconuts as a Model for Analysing the Injury Pattern of Cranial Blunt Trauma

Blunt trauma to the head may result in the blunt instrument leaving specific imprints or fracture patterns. Being able to correctly correlate one or more possible blunt instruments with the imprints and fractures of an actual case may be important in police investigations. However, most of our knowledge about blunt instruments and cranial imprints and fracture patterns stems from earlier tests performed on cadavers, or more recently, advanced mechanical and computerbased models. As the former is not feasible ethically, and the latter somewhat demanding in terms of laboratory settings and computer programming. Here we present our results by using a fairly simple model: a coconut shell. Striking a half coconut shell with four different blunt instruments did produce consistent imprinting and fracture patterning, which was also consistent with previously published cases. Also, in a blind trial we were able to correctly exclude one or more blunt instruments as the causative weapon. On the other hand, the blind trial also showed that the coconut is not applicable as a model to positively identify a blunt instrument unless the imprint or fracture pattern has a very characteristic shape.