• ABSTRACT
    • According to Ranvier (1889), cells in the ossification groove originate in cartilage and differentiate to osteoblasts. He was supported by others until some authors stated after 1950 that the growth plate grows in width by apposition of cells from the groove. The apposition theory is still accepted in several textbooks. Our experiments with roentgen ray injury showed (1950) migration of cells toward the ossification groove in the germinal layer of the growth plate, a phenomenon not described by others. It was verified in normal bones with 35S (1967) and with vital staining (1993). In situ hybridization of bones in rabbits showed (1993) that cells in the groove and adjacent periosteum contain type II collagen messenger RNA (mRNA) characteristic of cartilage, a finding in accordance with Ranvier's views. The behavior of cells in the ossification groove plays a decisive role in the pathogenesis of several diseases of the growing skeleton.