How Bones Develop

The development of our bones is a complex process.  Bone formation starts in the fetus 6 months before birth and is not generally complete until adolescence (between ages 13 and 18).

Bone formation is never really complete.  Bone is a living tissue made up of protein, calcium and other minerals, and water.  Bone tissue continuously renews itself by breaking down older bone and replacing it with new bone.  This process is called remodeling.

The cells that participate in the maintenance and remodeling of bone include:

  • Osteocytes (bone cells) that maintain bone as a living tissue;
  • Osteoclasts (bone breakers) that destroy bone; and
  • Osteoblasts (bone builders) that form the supporting matrix of new bone.

Bone health is important at any age and at every stage:

  • The childhood / growing years are the best time to develop healthy bones. During this time, new bone growth (bone formation) is greater than bone loss (bone resorption). This is an important time to build strong bones.
  • For adults, peak bone mass is reached in the mid- to late-30s. Bones are now fully developed. Adulthood is an important time to maintain strong bones.
  • In older adults, bone resorption begins to become more rapid, causing our bones to thin and weaken as we age. Late adulthood is an important time to slow or prevent bone loss.