How do growth plates help bones increase in length?

Growth plates, also known as epiphyseal plates, facilitate the longitudinal growth of long bones through a continuous process of cartilage production and replacement by bone tissue.123

This mechanism functions as follows:

• Cartilage Production: The growth plate consists of highly organized rows of cartilage cells. The layer farthest from the bony shaft, known as the germinal layer, is responsible for constant cell replication and the production of new cartilage.13
• Bone Replacement: On the side of the plate facing the bony shaft, cartilage cells undergo degeneration and calcification. This calcified cartilage is then replaced by new bone tissue (a process called endochondral ossification).13
• Constant Thickness: Because the rate at which new cartilage is produced by the germinal layer is closely matched by the rate at which it is replaced by bone on the shaft side, the growth plate maintains a relatively constant thickness while the bone itself increases in length.13

This process continues throughout childhood and adolescence until skeletal maturity, at which point the growth plates fuse and disappear, ending further longitudinal growth.123