fisis
Fisis, or physis, is the cartilaginous growth region at the end of a long bone where longitudinal growth occurs. It sits between the epiphysis (the bone end) and the metaphysis (the neck of the bone) and serves as the primary site of bone elongation during childhood and adolescence. In some languages the term is rendered as fisis.
The physis is organized into zones of reserve cartilage, proliferative cartilage, hypertrophic cartilage, and calcified cartilage,
Growth is controlled by systemic hormones such as growth hormone and thyroid hormone, by sex steroids during
Injury to the physis is a common concern in pediatric orthopedics. Physeal fractures can disturb normal growth
As growth ceases in late adolescence, the physis closes and is replaced by a bony epiphyseal line.