Attribution of hand bones to sex and population groups

Forensic anthropologists assign sex and population group (race) to individuals on the basis of skeletal remains. While the most useful bones for these determinations are cranial and pelvic, these are not always available. The purpose of this paper is to provide models for classification using metacarpals and hand phalanges. Four samples of 40 individuals each (black and white males and females) form the dataset. Measurements include lengths and radioulnar and dorsopalmar widths of the 19 bones of each hand. The large number of total variables necessitated separate models for metacarpal and phalangeal categories; due to the considerable number of significant differences between corresponding right and left hand variables, separate models were created for right and left sides. A stepwise discriminant procedure was used to select variables, with some highly correlated (r > 0.85) variables subsequently removed. The model for left hand metacarpals has the greatest power of discrimination (89.4%); that for right hand middle phalanges, the least (71.7%). Metacarpals assign approximately 87-89%, proximal phalanges 76-79%, middle phalanges 72-79%, and distal phalanges 81-83% of individuals to their correct sex and population groups. Models exchanging variables selected from one side for corresponding variables on the other show discriminating power ranging from 72.3 to 85.6%. Thus roughly 70-90% of individuals are correctly classified by these models; more conservative "jackknife" estimates yield a success rate of approximately 67-82%. When these models are used for classification of sex alone, 89.9-94.4% ("jackknife" range, 88.7%-94.4%) of cases are correctly classified; for race alone, 80.5-98.1% ("jackknife" range, 77.4-96.9%).