Determinants of Spatial Polarity in the Growth Plate |[bull]| 394

Growth of long bones occurs at the growth plate, a layer of cartilage that separates the epiphysis from the metaphysis. Growth plate exhibits spatial polarity. Proliferative chondrocytes undergo terminal differentiation when they approach the metaphyseal, but not the epiphyseal, border of the growth plate. The adjacent bone also exhibits spatial polarity. Metaphyseal, but not epiphyseal, blood vessels and bone cells invade adjacent growth plate, remodeling it into bone. As a result, the metaphysis, but not the epiphysis, elongates over time.