Establishment of a prediction method for the mid-facial region of unknown human Mongoloid skeletal remains

摘要

Forensic facial approximation is a technique used to estimate the antemortem facial features of unknown skeletal remains. In recent years, many researchers have reported nasal tip predictions with positive results. However, the morphological nasal features of the skull can vary widely, and it is hard to obtain accurate values using facial approximation techniques. We assumed that these variations are due to an over-dependence on the values obtained from a single distance metric factor in an anatomical area. Measurements were acquired using cephalometric radiographic images obtained from 190 Japanese individuals (90 men, aged 18-36 years and 100 women, aged 18-46 years). Soft tissue and skeletal features were traced onto acetate sheets. The orbitale (Or), porion (Po), and the Frankfurt Horizontal Plane (FHP) were plotted in addition to the rhinion (Rhi), anterior nasal spine (ANS), subnasale (Sn), prosthion, and point-A (A). From these, the following were measured: a length from rhinion to prosthion; b length from rhinion to the intersection of a line perpendicular to the anterior nasal spine; c length from the prosthion to the intersection of a line perpendicular to the anterior nasal spine; g the proportion of d/b; and f the proportion of c/b. A calculation was generated from these measurements and from proportions of a-h, and applied to the samples. An R-squared (RSQ) test and standard error (SE) were used to compare the actual and predicted values. The errors observed between the predicted and actual values were not greater than 5 mm in any of the samples; 91.3% and 71.2% of predicted Sn had an error lower than 2.5 and 1.5 mm respectively, from the actual. Reliable results were obtained using the method in the present study.