Validation of the new interpretation of Gerasimov’s nasal projection method for forensic facial approximation using CT data

Abstract

The most common method to predict nasal projection for the purpose of forensic facial approximation is Gerasimov’s two-tangent method. It was recently argued that previous validation studies did not properly perform Gerasimov’s original methodology and a revised set of guidelines was proposed. The aim of this study was to compare the accuracy of the different version of the two-tangent method using a sample of 66 postmortem cranial CT data. Intraobserver error was evaluated using a subsample of 10 individuals and the results demonstrated that experience affects the accuracy. Overall, the revised guidelines consistently resulted in smaller mean difference from the true tip. On the other hand, none of the methods were found to be statistically accurate (p>0.05) in positioning the tip of the nose (absolute distance > 5 mm). These results seem to support that Gerasimov’s method was not properly performed and the new guidelines should be used instead.