Testing Gerasimov’s two-tangent nose projection method in craniofacial approximations of children

Craniofacial approximation is an artistic process in which a potential face is created over the skull of an unknown individual in order to assist with identification. It is often not performed on children due to the lack of research in this area. There are currently several methods in use to predict the nose pronasale position, the oldest and purportedly most accurate and precise of which was the two-tangent method proposed by Mikhail Gerasimov in 1955 (13, 14, 17, 23, 24, 27, 28). To determine if this method is accurate for children of different age groups, 280 (140 male, 140 female) lateral cephalograms were imported into Adobe Photoshop® 7 where the soft tissue outline is removed to estimate the position of the pronasale using Gerasimov’s two-tangent method. The soft tissue outline layer was reapplied, and the predicted pronasale was compared to the actual pronasale using a Cartesian system. ANOVA and t-tests were performed to compare the position of the actual and predicted pronasale between age groups of the same sex, between sexes, and age groups of different sexes. Results show that this method only is accurate and precise for male juveniles between the ages of 9-12. According to these findings, Gerasimov’s two-tangent method should probably not be used for facial approximations on children.