Growth plates are structures that are present on both ends of the long bones of the body. This is also known as the epiphyseal plate. Epiphyseal plates can be found on the femur (the largest bone of the body), bones of the lower leg (both tibia and fibula), the paired bones of the forearm (radius and ulna) and the bones of the hands and feet.
The epiphyseal plate is made up of a flexible substance that is rich in collagen. This is the area where new bone growth occurs to match the growing individual. Growth is defined as an increase in both the bone length and diameter, causing a growth in the outward appearance.
As we age, this region of the bone closes and does not permit entry of minerals necessary for bone growth; thus, we stop growing once we reach 21. However, some abnormalities can alter this state, and this includes gigantism wherein there is an excess of overproduction of the growth hormone, thus leading to increased deposition of calcium in the bones, resulting in increased bone mass.