Relationship between hand function and bone morphology of phalanges and metacarpals

Abstract

In the first part of the paper, the authors present contemporary views which testify to the external regulation of growth in length of bones, as well as to the influence that mechanical stress can have on bone growth in width, and on structure of cortex. In the second empirical part, quantitative data were presented on the lengths, and widths of distal and proximal epiphyses of phalanges and metacarpals (fig. 1). Material comprises 30 mental workers and 39 physical workers (with average vocational practice of 12 years). No differences were found between the two groups in lengths and widths of the studied bones. In the group of physical workers, however, significantly higher variances were observed in lengths of the measured bones (tab. 1), while width variances were consistent over the two groups (tab. 2, 3). The differences were accounted for by the variable impact of mechanical stress during intensive growth of bones in length in the group of physical workers. These differences could not be ascribed to different body statures, weights nor age, as these variables were controlled when selecting subjects to the groups. In order to estimate the effect that vibration and mechanical stress can have on changes in thickness of cortex, measurements of widths were taken from diaphyses of second metacarpals, and from the bone channels (fig. 2). No differences in any of the two dimensions were found nor, respectively, in the cortical index which in both groups amounted to 58% (tab. 4, 5).