The Use of Micro-CT Analysis of the Second Metacarpal to Assess Cortical Bone Loss in Archeological Human Skeletal...

The assessment of cortical bone loss in archeological populations can give insights into past lifeways and bone health. The second metacarpal index (MCI) is assessed via radiogrammetry to quantify cortical thickness. However, as this method is limited to a single-point measurement, this study explores the use of micro-computed tomography (μ-CT) to provide additional cross-sectional parameters as indicators of cortical bone loss.

μ-CT scans were generated for a sample of 46 second metacarpals from two medieval skeletal assemblages from Scotland, UK. Measurement for MCI, cortical area fraction and intracortical porosity were taken at the mid-point of the diaphysis. They were then assessed for correlation between each parameter and for patterns in bone loss associated with age and sex.

The MCI revealed a gradual decline in cortical thickness with advancing age for both males and females. There was a significantly lower MCI (associated with bone loss) in older individuals compared to younger adults (p < 0.05). No significant differences in MCI were detected between the sexes within any age group. A strong positive correlation was identified between MCI and cortical area fraction (r = 0.873), while MCI and intracortical porosity percentage had a weak negative correlation (r = -0.401).

μ-CT assessment of the second metacarpal allowed for a more extensive cortical analysis, demonstrating that while the MCI is an effective indicator of cortical thinning, assessment of intracortical porosity can provide further insight into the analysis of cortical bone loss within past populations.