Statistical classification methods for estimating sex based on five skull traits: A nonmetric assessment using 3D CT models.

Five cranial nonmetric traits for sex estimation for sex estimation are classified by score according to geometry. The population of origin is one of the factors influencing cranial nonmetric traits. Moreover, among the five cranial traits, the robust traits for estimating sex varied across population. The aim of this study is to suggest the most useful method for sex estimation and demonstrate the need of a suitable method for each population. One-hundred thirty-five three-dimensional skull images from 21st century Korean autopsy cadavers were evaluated using the ordinal scoring system of five cranial nonmetric traits as outlined in Buikstra & Ubelaker (1994). All scores of each trait were analyzed by linear discriminant and decision tree analyses for sex estimation. The frequency of each trait was analyzed and compared to populations from other studies. The accuracy for both sexes was 88.1% by discriminant analysis and 90.4% by decision tree. The traits with the highest accuracy were the glabella and mastoid process in both discriminant analysis and decision tree. Sex estimation in modern Korean cadavers using the cranial nonmetric method was shown to be highly accurate by both discriminant analysis and decision tree. When comparing the pattern of frequency scores in this study with those of other populations, the pattern of trait scores for estimating sex was different for each population, even among populations in the same Asian region, which suggests the need for methods suited for specific populations.

Estimation of stature from femur length measured using computed tomography after the analysis of three-dimensional characteristics of femur bone in Korean cadavers.

Estimation of stature is a basic and important forensic procedure in identifying decomposed or skeletonized bodies. Due to advances in radiologic equipment, forensic science frequently uses computed tomography (CT) and software to apply these findings to investigations. Technical developments have increased the accuracy of the measurement of various bones. However, there are still some inaccuracies, such as defining correct landmarks in three-dimensional (3D) images. Femur length is frequently used for calculation of stature, but because it is a 3D structure, the digital image may not always correlate with the femur length measured with an osteometric board. However, more studies are now showing that the maximum femur length calculated in 3D imagery is comparable to the maximum femur length calculated using an osteometric board. This study used digitalized data of the femur obtained from the CT image through the specialized software. The digitalized femur images were put on the virtual osteometric board, which helped us to understand the anatomic characteristics of the femur and to confirm that the maximum femur lengths calculated in 3D images are similar to the results obtained using an osteometric board. These data were used to obtain a stature estimation formula for the Korean population.