When Do People Stop Growing?
People stop growing when their bones do, and that is usually between 15 and 25 years of age. Bones are made up of living tissue, composed of special cells which secrete round themselves material rich in calcium salts and as hard as marble. The formation of bone (ossification) is a complex process which usually begins in cartilage (gristle).
Growth refers to a positive change in size, and/or maturation, often over a period of time. Growth can occur as a stage of maturation or a process toward fullness or fulfillment. It can also perpetuate endlessly, for example, as detailed by some theories of the ultimate fate of the universe.
In a child the bone begins to form in the middle of the cartilage and spreads towards both ends, turning it all to bone with the exception of the tips. From these points the bone grows in length and so does the child. When the growing period is over, the tips of the bones close by joining the main shaft of the bone.
In the human body at birth, there are over 270 bones, but many of these fuse together during development, leaving a total of 206 separate bones in the adult, not counting numerous small sesamoid bones. The largest bone in the body is the femur or thigh-bone, and the smallest is the stapes in the middle ear.
The Latin word for bone is os, hence the many terms that use it as a prefix – such as osseous and osteopathy. Bones vary greatly in shape and size. Long ones act as levers. Flat ones are centres for muscle action. But each has a cavity containing bone marrow.
Around this the bony substance is spongy in texture, becoming hard nearer the surface where the calcium is densest. On the surface of the bone is a special layer of fibrous tissue (the periosteum) which is rich in bone-building cells.