[Optical, scanning electron and atomic force microscopic observation of the microstructure of human humeral bone].

Objective: To observe the microstructure of human long bone with scanning electron and atomic force microscopes to understand the ultrastructural organization and the composition and the morphology of the bone collagen and minerals.
Method: Fresh human cadaveric humeral bone were fixed and dehydrated to prepare the ground sections and thin slices, respectively, which were observed for bone microstructure using optical, scanning electron and atomic force microscopy, respectively.
Results: Under optical microscope, the bone lacunae were in circular permutation around the Haversian canal, and the canaliculi communicated the lacunae and Haversian canal or between the lacunae. Atomic force microscopy represented distinct morphology of the large clusters of collagen, and the collagen fibers thickened in the mineralized zone and appeared in the shape of overlapping discs, whereas the calcium-phosphorus crystal displayed ellipse cylinders. The size, shape and relation of the canaliculi and lacunae were observed clearly. The bone matrix was observed in circular arrangement along the Haversian canal and the calcium-phosphorus crystal was in regular alignment under scanning electron microscope.
Conclusion: Atomic force microscopy can help analyze the three-dimensional configuration of calcium-phosphorus crystal and bone collagen as well as the canaliculi and lacuna. The canaliculi serve as the channels mediating alimentation and molecular signals into the lacuna.