title: A review of the actual knowledge of the processes governing growth and development of long bones.
abstract: Autoptic samples of human bones (from 8 weeks of gestation to 12 years of age) and a second group of serial, skeletal x-rays (required for pathologies not related to bone dysplasia in children from 4 months to 17 years of age) provided the material for the analysis of the physes normal growth mechanism presented in this review. Before the appearance of the ossification centers epiphyseal growth rests exclusively on chondrocytes proliferation (interstitial growth), without any detectable differentiated cellular organization. When endochondral ossification starts a defined spatial disposition of chondrocytes and a corresponding organization of the intercellular matrix is set up, so that it is possible to identify a growth vector corresponding to the columns of piled chondrocytes with direction from hypertrophic toward the proliferative cell layers. The complexity of the tubular bones growth process is well represented by the spatial arrangement of the growth vectors. In the late epiphyseal growth another mechanism is active in addition to endochondral ossification, namely, articular cartilage interstitial growth and subchondral remodelling. The knowledge of the normal mode of organization of the physis and its temporal sequence can help to better understand of the deviaton from the normal development of metaphyseal and epiphyseal dysplasias.
authors.affiliation: Orthopaedic Clinic, University of Brescia, Brescia, Italy.
authors.forename: Ugo Ernesto
authors.initials: UE
authors.lastname: Pazzaglia
authors.forename: Giampiero
authors.initials: G
authors.lastname: Beluffi
authors.forename: Anna
authors.initials: A
authors.lastname: Benetti
authors.forename: Maria Pia
authors.initials: MP
authors.lastname: Bondioni
authors.forename: Guido
authors.initials: G
authors.lastname: Zarattini
mesh_terms: D000293:Adolescent; D001846:Bone Development / Q000502:physiology*; D001842:Bone and Bones / Q000196:embryology; D002648:Child; D002675:Child, Preschool; D019902:Chondrocytes / Q000166:cytology; D020219:Chondrogenesis / Q000502:physiology; D004838:Epiphyses / Q000254:growth & development; D047109:Fetal Development / Q000502:physiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008953:Models, Anatomic; D010012:Osteogenesis / Q000502:physiology; D012016:Reference Values