Cortical bone was collected from the femurs of animals of different species and from femurs and ribs of humans of different ages. Sizes of osteones and their canals and thickness of cortex were measured.
There appears to be an upper limit to the size of the osteone in animals of different species.
In the femur and in the rib of man osteones remain approximately the same size throughout life.
In man Haversian canals increase in size with age in the femur cortex but remain in the same size in the rib; in the rib, this is accompanied by a decrease in cortical thickness.