A Handy Study of Secular Change in Metacarpals using the Terry Collection and UTK Donated Skeletal Collection

Hand morphology reflects an individual’s physical interaction with the world around them. Technological innovation, improved nutrition and health, changes levels of physical activity, and other environmental factors provoke secular change in skeletal morphology. This study elaborates on previous secular change research that has documented the narrowing of the American skeletal form in recent American history, and it contributes new information to this field by focusing on metacarpals. By utilizing a dataset comprising individuals from the Robert J. Terry Collection (N=213) and adults from the UTK Donated Skeletal Collection (N=180), this study examines metacarpal morphology for secular change over a 170-year time frame. The dataset was divided into six cohorts based on year of birth. Four measurements were taken of each metacarpal and each was examined using a one-way ANOVA. Interobserver error was assessed using pair-sample t-tests. Additionally, percentage directional asymmetry and correlations of stature and metacarpal dimensions were calculated. Measurement differences were found for the head breadth and base breadth, limiting the utility of these dimensions for analysis. The midshaft breadth exhibits extremely subtle secular change in the form of medio-lateral narrowing. The head breadth, despite the measurement differences, also exhibits a trend of decreasing in size over time. The length measurement is fluctuating over time with no clear trend. The significant differences between cohorts for males and females are not consistent across measurements. Males exhibit more significant differences between cohorts for the midshaft breadth, and females exhibit more significant differences between cohorts for length. The amount of left-side asymmetry is higher for the cohorts from the UTK Collection. Stature is most strongly positively correlated with the length measurements. This study contributes another layer of understanding to the development of the modern human skeleton.