Human femur sectioned parallel to long axis of femur.

Abstract

<p>a) bright field (BF) image: faint bands oriented NW-SE, repeated every 68 nm, denote concentration of HA in gap zones in collagen fibrils which run perpendicular to the bands. Perpendicular to the bands are ∼23 nm wide bundles spaced ∼50 nm apart comprised of clusters of linear features (arrow) 5±1 nm wide, and up to 200 nm in length; b) selected area diffraction pattern indexed to HA; note that 00l reflections form arcs indicating preferred orientation of the c axes of the HA parallel to the to the fibrils, while other reflections form complete circles, lack of alignment of the a and b axes.</p