Bone Formations

Bone formation, also called ossification, process by which new bone is produced. Ossification begins about the third month of fetal life in humans and is completed by late adolescence. The process takes two general forms, one for compact bone, which makes up roughly 80 percent of the skeleton, and the other for cancellous bone, including parts of the skull, the shoulder blades, and the ends of the long bones.

There is a rapid formation of bone mass in the fetus and infant. This slows somewhat during childhood until age 11 in females and a year or so later in boys. During the growth spurt that accompanies adolescence, tremendous bone formation occurs. The vast majority of adult levels of bone mass are achieved by age 18 or so, with only a small amount added until about 28 years old.

There are a number of hormones that are important to this rapid formation of bone during the first two decades of life. These hormones include, estrogen in females, testosterone in males, growth hormone, and some other minor hormones.