- Epiphyseal plate
The epiphyseal plate (or epiphysial plate, physis, or growth plate) is a hyaline
cartilage plate in the metaphyses of children and adolescents.Anatomy & Development
Epiphyseal plates are present in growing bones. They are found in children and are present through puberty and early adulthood. cite web|url=http://training.seer.cancer.gov/module_anatomy/unit3_3_bone_growth.html|title=Skeletal System / Bone Development and Growth|accessdate=2008-07-10] These plates are located at one or both ends of bones between the
epiphysis (end) and thediaphysis (shaft) of long bones. Growth occurs towards the diaphysis or shaft of the long bone. [cite web |url=http://science.nhmccd.edu/biol/epiphyss/epiphys1.html|title= Direction of Long Bone Growth
publisher=North Harris College|accessdate=2008-01-15] In most adults, the epiphyseal platesossify by the mid twenties and growth arrests.Role in Bone Elongation
Whereas
endochondral ossification is responsible for the initial bone development from cartilagein utero and infants, the epiphyseal plate is responsible for longitudinal growth of bones. The plate'schondrocytes are under constant division bymitosis . These daughter cells stack facing theepiphysis while the older cells are pushed towards thediaphysis . As the older chondrocytes degenerate,osteoblasts ossify the remains to form new bone. Around the end of puberty, the epiphyseal cartilage cells stop duplicating and the entire cartilage is slowly replaced by bone, leaving only a thin epiphyseal line. Once the adult stage is reached, the only way to manipulate height is modifying bone length viadistraction osteogenesis .The growth plate has a very specific morphology in having a zonal arrangement. The growth plate includes a relatively inactive reserve zone at the epiphyseal end, moving distally into a proliferative and then hyper trophic zone and ending with a band of ossifying cartilage (the metaphysis). The growth plate is clinically relevant in that it is often the primary site for infection, metastasis, fractures and the effects of endocrine bone disorders.Fact|date=July 2008
Pathology
Defects in the development and continued division of epiphyseal plates can lead to growth disorders. The most common defect is
achondroplasia , where there is a defect in cartilage formation. Achondroplasia is the most common cause ofdwarfism .Salter-Harris fractures can occur on epiphyseal plates.tudies in Animals
John Hunter studied growing chickens. He observed bones grew at the ends and thus demonstrated the existence of the epiphyseal plates. Hunter is considered the "father of the growth plate". [cite web |url=http://www.emedicine.com/orthoped/topic627.htm|title= Growth Plate (Physeal) Fractures
publisher=EMedicine.com|accessdate=2008-01-15]References
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