“Bone is a miniature universe in which birth and death occur constantly. The basic unit is the osteon, composed of concentric loops of bone, a canal, osteocytes, vessels, and nerves. In living tissue osteons are born, nourished, and eventually replaced by newer units. When magnified and viewed under polarized light, osteons resemble tiny volcanoes, ovoid cones with central craters and flanks that spread out to flatlands of primary bone. The number of volcanoes increases with age, as does the count of abandoned calderas. By determining the density of these features one arrives at an age estimate.”
Book:Fatal Voyage
