One for all and all for one: Linear regression from the mass of individual bones to assess human skeletal mass completeness.

OBJECTIVES

Complete and accurate human skeletal inventory is seldom possible in archaeological and forensic cases involving severe fragmentation. In such cases, skeletal mass comparisons with published references may be used as an alternative to assess skeletal completeness but they are too general for a case-by-case routine analysis. The objective is to solve this issue by creating linear regression equations to estimate the total mass of a skeleton based on the mass of individual bones.

MATERIALS AND METHODS

Total adult skeletal mass and individual mass of the clavicle, humerus, femur, patella, carpal, metacarpal, tarsal, and metatarsal bones were recorded in a sample of 60 skeletons from the 21st century identified skeletal collection (University of Coimbra). The sample included 32 females and 28 males with ages ranging from 31 to 96 years (mean = 76.4; sd = 14.8). Skeletal mass linear regression equations were calculated based on this sample.

RESULTS

The mass of individual bones was successfully used to predict the approximate total mass of the adult skeleton. The femur, humerus, and second metacarpal were the best predictors of total skeletal mass with root mean squared errors ranging from 292.9 to 346.1 g.

DISCUSSION

Linear regression was relatively successful at estimating adult skeletal mass. The non-normal distribution of the sample in terms of mass may have reduced the predictive power of the equations. These results have clear impact for bioanthropology, especially forensic anthropology, since this method may provide better estimates of the completeness of the skeleton or the minimum number of individuals. Am J Phys Anthropol 160:427-432, 2016. © 2016 Wiley Periodicals, Inc.