Prediction of nasal morphology in facial reconstruction: Validation and recalibration of the Rynn method.

Abstract

Prediction of the nose from the skull remains an important issue in forensic facial approximation. In 2010, Rynn et al. published a method of predicting nose projection from the skull. With this method, three craniometric measurements (x, y, z) are taken, and these are then used in regression formulae to estimate the nasal dimensions. The purpose of this study was to examine and test the accuracy of the Rynn et al. method and if necessary to adapt the formulae for this population. A sample of 90 CT scans of Turkish adults was used in the study. The actual and predicted dimensions were compared using t-test. The age of the individuals ranged from 20 to 40 years by sex. The descriptive statistics and correlations were calculated, and the actual and predicted measurements were compared. The differences between the actual and predicted values were statistically significant (p < 0.01), with -1 mm for males and -1.5 mm for females. Validation accuracies ranged from 76 to 92% in females and 72 to 82% in males. Recalibration equation accuracies ranged from 88 to 100% in females and 90 to 100% in males. The results showed that the recalibration of the Rynn et al. method and its formulae gave satisfactory results with less error and can be employed in facial approximation cases.