NUMBER OF OSTEOBLASTS PER UNIT AREA OF OSTEOID SEAM IN CORTICAL HUMAN BONE

Abstract

The fifth, sixth, or seventh ribs from 97 metabolically normal people of all ages were examined. Mineralized longitudinal sections were specially stained to show both osteoid seams and osteoblasts. In 19 persons, the mean number of osteoblasts per mm² of active osteoid seam surface on 111 seams was 4500. In 66 persons, a layer of osteoblasts was present on only 29% of 121 seams. The seams without layers of osteoblasts nevertheless were part of actively forming Haversian systems as judged by other criteria. No significant age differences were observed in either value.