A TETRACYCLINE-BASED EVALUATION OF THE RELATIVE PREVALENCE AND INCIDENCE OF FORMATION OF SECONDARY OSTEONS IN HUMAN CORTICAL BONE

Abstract

In mineralized sections of 160 adult human bones, the relative prevalence of three major kinds of secondary osteons was compared with the relative incidence with which they were formed, the latter with the aid of bones that had been marked in vivo with tetracycline antibiotics. Relative prevalence and incidence were similar, implying that the biological lifetimes of the three osteon types are similar. Unremodeled secondary osteons were about 90% of the total osteon population, and also of the labelled-bone forming sites. Each of the 822 tetracycline-labelled foci of bone formation that were found inside the cortices of various bones belonged to one of the three osteon types that were studied, and no other kinds of labelled sites were observed. This implies that osteonal remodeling is the major mode of osteoblastic activity inside of cortical bone.