Bone strength in Medieval Denmark: robusticity analyses from a rural and urban sample

Abstract

Objectives: The aim of the current study was to understand the transition in lower limb loading and terrestrial mobility during the urbanization revolution in medieval Denmark. This was accomplished by comparing the cross sectional geometric properties of the femora from two populations, the rural cemetery of Tirup and the urban Black Friars cemetery. Materials and Methods: Using two skeletal samples, the rural cemetery of Tirup, Jutland (1150-1350 A.D.), and the urban Black Friars cemetery, Funen (1240-1607 A.D.), cross sectional geometric properties of the right femora were examined. The cross sectional geometric properties of adult long bones are reflections of in-vivo loading. General patterns of relative mechanical loading during life can be interpreted by calculating the cross sectional geometric properties of a long bone’s diaphysis. Compressive and tensile rigidity and strength (CA), maximum and minimum bending rigidity (Imin, Imax), torsional rigidity (J), bending rigidity along the anteroposterior and mediolateral axes (Ix, Iy), and diaphyseal shape (Imax/Imin; Ix/Iy) at the femoral midshaft were calculated from 104 CT scans, 48 from Tirup (32 males, 16 females) and 56 from Black Friars (38 males, 18 females). Results: The results indicate significantly greater robusticity among the Black Friars sample for both males and females. Discussion: In opposition to the prevalent understanding of physicality in medieval communities, the results suggest that lower limb loading (and inferred terrestrial mobility) was greater in the urban setting. Cemetery make-up and population variation between the samples cannot, however, be discounted.