epiphyselinjer

Epiphyselinjer, also known as epiphyseal plates or growth plates, are areas of hyaline cartilage found in the metaphysis of long bones. These are the sites of longitudinal bone growth in children and adolescents. Each long bone has at least two epiphyselinjer, one at each end.

The epiphyselinjer are composed of several zones of chondrocytes. The zone of proliferation contains actively dividing chondrocytes. These cells then mature and hypertrophy in the zone of hypertrophy. In the zone of calcification, the cartilage matrix is calcified, and in the zone of ossification, osteoblasts lay down new bone tissue on the calcified cartilage scaffold.

Bone growth occurs as chondrocytes in the epiphyselinjer multiply and the cartilage matrix is replaced by bone. This process continues until puberty, when hormonal changes, primarily involving sex hormones, lead to the gradual replacement of the cartilage in the epiphyselinjer with bone. Once the epiphyselinjer close, longitudinal bone growth ceases.

Fractures through the epiphyselinjer can occur in children and adolescents and are known as Salter-Harris fractures. These fractures are classified into five types based on their relationship to the epiphysis, physis (growth plate), and metaphysis. The type of fracture can influence the prognosis for future bone growth. Epiphyseal plate injuries can lead to premature closure of the growth plate and subsequent limb length discrepancy or angular deformities.