Fig. 3. Diagrammatic illustration of the fact that vertical trabeculae bow slightly when loaded. Resorption pits in the side of such trabeculae serve as stress concentrators, since the prior load must now be borne by a smaller cross-section. The result is a tendency to snap with usual load-bearing activities. Hundreds of such healed or healing trabecular fractures can be found in osteoporotic bone by micro-dissection. (Copyright Robert P. Heaney, 2005. Used with permission.)