pituuskasvualueet

Pituuskasvualueet, meaning growth zones or growth areas, refers to the regions within a bone that are responsible for longitudinal growth. In long bones, the primary site of this growth is the epiphyseal plate, also known as the growth plate. This cartilaginous layer is located between the epiphysis (the rounded end of the bone) and the diaphysis (the long shaft of the bone). Within the epiphyseal plate, chondrocytes (cartilage cells) proliferate, mature, and eventually die, being replaced by bone tissue. This process leads to the lengthening of the bone.

Another important growth area is the periosteum. While the epiphyseal plate primarily contributes to bone length, the periosteum plays a crucial role in increasing bone width or diameter. This membrane, which covers the outer surface of bones, contains osteoblasts (bone-forming cells) that deposit new bone tissue on the outer surface of the diaphysis. Simultaneously, osteoclasts (bone-resorbing cells) on the inner surface of the medullary cavity remove bone, thus widening the bone while maintaining its overall structure.

These growth zones are active during childhood and adolescence, driven by hormonal influences, particularly growth hormone and sex hormones. As an individual reaches skeletal maturity, typically in late adolescence or early adulthood, the epiphyseal plates ossify, meaning the cartilage is replaced by bone. Once ossification is complete, longitudinal bone growth ceases. The periosteum, however, continues to remodel bone throughout life, contributing to bone strength and repair. Understanding pituuskasvualueet is essential in studying skeletal development, growth disorders, and conditions affecting bone health.