A microradiographic study of tibial bone from twenty-one ischemic human legs and twelve non-ischemic legs was undertaken to determine the relationship of ischemia to plugged canals and filled lacunae. A statistically significant increase of filled lacunae in the ischemic bone and in the interstitial areas was found, indicating a positive correlation between filling of lacunae and ischemia. No difference between ischemic and control bone was found in respect to percentage of plugged canals. The concept of uninhibited centripetal growth of osteons to form bone-filled canals is presented.