Estimating the length of incomplete long bones: forensic standards from Guatemala

We report on new standards for estimating long bone length from incomplete bones for use in forensic and archaeological contexts in Central America. The measurements we use closely follow those defined by Steele ([1970] Personal Identification in Mass Disasters; Washington, DC: Smithsonian Institution), but we add several new landmarks. We measured the femur, humerus, tibia, and fibula of 100 Maya skeletons (68 males, 32 females) recovered from forensic exhumations. We derived the equations by regressing bone segment length on bone length, and solved for bone length to maximize the utility of the equations for taller populations. We generated equations for all segments that were significantly correlated with bone length for males, for females, and for both sexes combined, but accepted only regressions with r(2) > 0.85 as reliable. Landmarks defined by muscle attachment sites were more variable in location than landmarks on articular architecture; thus we retained few equations that use these landmarks. We tested the male and combined sex equations on 36 males of unknown ethnicity exhumed from a military base in Guatemala, and found that the equations performed satisfactorily. We also evaluated the performance of equations by Steele ([1970] Personal Identification in Mass Disasters; Washington, DC: Smithsonian Institution) and Jacobs ([1992] Am J Phys Anthropol 89:333-345) on the Maya bones, and conclude that significant population variation in long bone proportions hinders their application in Central America.