TY - CHAP M1 - Book, Section TI - Metabolic Bone Diseases A1 - Wells, Robert G. PY - 2015 T2 - Diagnostic Imaging of Infants and Children AB - The growth plate is an important site of involvement with many of the metabolic bone diseases. The physis, or growth plate, is composed of chondrocytes that are arranged in an orderly fashion. There are 3 histological and functional zones of the physis. The reserve, or germinal cell, zone is adjacent to the epiphysis and contains chondrocyte precursors. This is an important site of regulation of the cellular components of the physis. The proliferative and hypertrophic zones are characterized by the presence of chondrocytes that are organized into columns. The hypertrophic zone is subdivided into zones of maturation (columns of cartilage cells), degeneration, and provisional calcification. The transition between cartilage and bone occurs at the zone of provisional calcification and adjacent portion of the metaphysis. Metaphyseal vessels invade chondrocytes in the portion of the hypertrophic zone closest to the metaphysis. Mineralization of the longitudinal cartilaginous septa of the hypertrophic zone with hydroxyapatite crystal forms a dense but fragile layer, the zone of provisional calcification. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - accesspediatrics.mhmedical.com/content.aspx?aid=1148953335 ER -