Metafysen

Metafysen, or metaphysis in English, is the region of a long bone between the epiphysis (the end) and the diaphysis (the shaft). In growing individuals the metaphysis is located near the growth plate (physis) and is the site where long bones lengthen through endochondral ossification. The region contains cancellous (spongy) bone and red bone marrow and is richly supplied with blood vessels.

During development, cartilage near the epiphyseal plate is gradually replaced by bone in the metaphysis as the bone grows. The metaphysis forms a transitional zone that connects the cartilaginous physis to the solid diaphysis. After the growth plates fuse in adulthood, the metaphysis remains as part of the mature bone, with less cartilage and no further longitudinal growth.

Clinical relevance: The metaphysis is a common site of injuries in children, including metaphyseal fractures and growth plate injuries (Salter-Harris types). It is also a location where osteomyelitis can develop in pediatric patients due to the region’s vascularity. Metaphyseal abnormalities may be seen in metabolic bone diseases and growth disorders.

Etymology: The term metaphysis derives from Greek meta- “beyond” and physis “growth,” referring to its position beyond the growth plate.