Small-angle X-ray scattering study of intramuscular fish bone: Collagen fibril superstructure determined from equidistant meridional reflections

New insights into the bone collagen fibril superstructure have been obtained by novel small-angle X-ray scattering analysis. The analysis was carried out on the small-angle equidistant meridional reflections resulting from the periodic structure of collagen fibrils in their axial direction. Conventional two-dimensional analysis is difficult because of the large discrepancy of longitudinal and lateral length scales for individual fibrils, as well as their preferred orientation. The new approach represents an unapproximated analysis of the equidistant meridional reflections, which takes the exact separation of preferred orientation and fibril size effects into account. The analytical results (e.g. axial period, fibril diameter etc.) agree well with the parameters obtained from transmission electron microscopy.