SCANNING ELECTRON-MICROSCOPY OF COLLAGEN FIBER ORIENTATION IN THE BONE LAMELLAR SYSTEM IN NONDECALCIFIED HUMAN SAMPLES

Previous studies on collagen fiber orientation have led to different i nterpretations and theories about the fiber arrangement in the lamella r compact bone. The purpose of this investigation was to provide new a nd more in-depth data on fiber arrangement in the lamellar bone system in order to explain the orientation of the fiber bundles. This was ca rried out by applying a simple method of preparation which permitted o bservation of non-decalcified samples. A previously isolated Haversian system was subjected to slow bending up to reaching the fracture poin t. Hence, the fracture surface was observed by SEM. The same samples w ere also observed by polarized light microscopy. A significant alterna tion of fiber orientation in the adjacent lamellae was observed. Diffe rent domains of differently oriented fibers were present within the sa me lamella; conjugating fibers connecting adjacent lamellae were also shown. This method avoided most of the artifacts due to chemical treat ment of bane samples. The results can be easily interpreted by means o f the same criteria applied in mechanics for the studying of composite materials.