The relationship of structure to mechanical function in the third metacarpal bone of the horse, Equus caballus

Abstract

The relationship of structure to mechanical function is investigated for the third metacarpal of the domestic horse, Equus caballus, as a basis for extrapolating to the functional interpretation of bone structure in fossil equids. The orientation and density of trabeculae in the proximal and distal cancellous regions of the bone are assessed from sections and radiographs, and are quantified stereologically. The principal forces transmitted to the cancellous regions are reconstructed from in vivo strain gauge data in the literature. The major trabecular systems in the bone are oriented and positioned to resist and transmit the forces acting on them, and correlations between structure and function are described. These correlations indicate the potential utility of the results as a basis for interpreting the structure of the homologous bone in extinct equids.