Q. How do bones grow?
Bones form and develop through a process known as ossification. There are two types of ossification: endochondral ossification and intramembranous ossification. Intramembranous ossification is the formation of bone directly on or within fibrous connective tissue. Illustrations of bone formed through intramembranous ossification are flat bones of the skull, mandible (lower jaw), and clavicle (collarbone). Endochondral ossification, from Greek endo, meaning "within," and khondros, meaning "cartilage," is transformation of cartilage model into bone. Cartilage cells in epiphyseal plate grow and move into metaphysis where they are reabsorbed and replaced by bone tissue. Illustrations of bone formed through endochondral ossification are the long bones, like femur and humerus.