Sex Estimation from the Upper End of Bulgarian Femur Using 3D Hand-Held Laser Scanner
The present study aimed to establish standards for determining sex from the upper end of the femur in a modern Bulgarian population focused on an innovative approach to the numerical assessment of gluteal tuberosity through 3D visualization and its use as a sex predictor. The sample is composed of 156 femora. Seven measurements were taken: vertical head diameter, transverse head diameter, maximum head diameter, head circumference, sagittal subtrochanteric diameter, transverse subtrochanteric diameter and supero-inferior neck diameter. The surface of gluteal tuberosity was captured in a 3D image, using a hand-held laser scanner. A 3D shape comprising two tetrahedrons with a common base was constructed. The volume of the rough area of muscle insertion was approximately equal to the sum of the area of volumes of these two tetrahedrons (volume). Several points were placed on the surface of the area of roughness on the 3D image. Based on these points a two-dimensional shape was created which was a function of the three-dimensional one. Thus, volume, area of the newly-formed shape, its greatest elevation and the three angles between the constructed planes were used as sex predictors. The mean values of all metric and 3D measurements showed significant differences between genders p<0.001, volume p=0.02. According to stepwise discriminant analysis the combination of head circumference, sagittal subtrochanteric diameter, transverse subtrochanteric diameter and supero-inferior neck diameter provided 88.5% accuracy. Using the same analysis the combination of volume, elevation and angle b1 provided the best result with 93.0% accuracy.