A SEM study of osteocyte orientation in alternately structured osteons.

Previous morphometric analyses, carried out by means of the light microscope show the existence of a close relationship between size, shape, orientation of osteocytc lacunae and collagen texture in both woven bone and longitudinally structured secondary osteons (Marotti 1979, 1980). However these investigations, owing to the technique applied, failed to demonstrate the orientation of the triaxial osteocyte ellipsoids in lamellar bone with alternate orientation of fibers. In the present study the SEM was used to measure the sectional area and the axes of osteocyte lacunae in secondary osteons with different types of lamellation. Compact bone from tibiae of normal men of various age was etched with N/10 HCl for 90", and treated with Trypsin (80 µg/ml, pH 7.4 for 41h at 37°C) before being gold-palladium coated for the SEM analysis. The results obtained are in close agreement with those of the previous investigations as regards the orientation of osteocytes in woven bone and in longitudinally structured osteons. Tn addition they show that in lamellar osteons with alternate orientation of fibers the osteocytes are mainly located in longitudinally structured lamellae with their major axis at an angle of 26-27° with respect to the longitudinal axis of the Haversian canal.