1Department of Anatomy and Cell Biology, University of Saskatchewan, 2Melbourne Dental School, University of Melbourne
March 27, 2015 , Archview Ballroom
This study used synchrotron high resolution micro-CT scanning to reconstruct three-dimensional osteonal networks in cortical bone and analyze their interconnectivity across age. Secondary osteons result from bone remodelling processes, accomplished by Bone Multicellular Units, the coordinated activity of osteoclasts and osteoblasts. Most of our knowledge about osteonal networks derives from two-dimensional microscopy, which is limited in its ability to reveal their complex nature. For this reason, the present study reconstructed three-dimensional osteonal networks (2.925 mm3 volumes of interest) of six male femoral samples (20-71 years) from the anterior cortex. Since remodelling continues throughout life, we hypothesized that osteonal networks should show significant age differences in the frequency of branching events (acutely-angled branches) and Volkmann’s connections (transversely-oriented) per osteon. Results revealed great variation in branching events, in most cases connected to ‘repathing’ (a younger osteon growing inside an older osteon). In general, Volkmann’s connections were most frequent with individuals sometimes showing a preference for transverse versus slightly sloped canals. Despite age trends in connection types, the total number of connections was similar across all ages. Osteons had an average number of branching events ranging at 1.6-2.7 within the reconstructed volume. Volkmann’s canals tended to become less frequent with age while the opposite was the case for branching and repathing events. Contrary to expectations that fragments are avascular, we also frequently observed fragments with canals, connected to more recent osteons by Volkmann’s tunnels. Future research will address these and other complex interconnections in more detail.
This research is funded by the Canada Research Chairs program and the Canadian Foundation for Innovation.