Your Bones: What are growth plates?

David E. Attarian, MD, of Duke Total Joint Center, and Andre C. Grant, MD, of Duke Orthopaedics of Raleigh, provide answers in this Q&A session:

bone growth plate

What are growth plates?

Growth plates are the soft parts at each end of our bones. Most bones grow by the contribution of new bone from the growth plate.

Because of their soft nature, these parts of the bone are vulnerable to injury during the development of a child. This is a weak area of bone that is sometimes weaker than the surrounding tendons and ligaments.

Most bones have a growth plate at either end. Throughout childhood, these growth plates give length to the bones.

When do growth plates close in people?

It is difficult to know when exactly each growth plate will reach the end of its function, but there this an average time when these plates should close.

Growth plates close at skeletal maturity, meaning the person stops growing. So for women, a year or two after they begin their menses (age 14 to 17 years), and for men age 18 to 22 years.

The growth plate starts contributing to growth in utero and continues to do so at different rates during development. Just before puberty, most growth plates increase their rate of contribution to growth and eventually slow down.

Puberty is a quite variable stage of adolescence. Therefore, it is difficult to know how much growth is left until the growth plates close down.

Females tend to hit their peak growth at around age 13 to 14, and boys at 14 to 15. This is also variable depending on a multitude of genetic and environmental factors. A good estimate of how much growth remains is to compare the heights of females or males within a one family.

How is remaining growth estimated?

For orthopedic surgeons, we can use different x-ray markers to better estimate the amount of growth a child has remaining.

A good rule of thumb is once a child has reached the end stages of puberty, their individual rate of growth thereafter should slow down quite significantly until eventually, the growth plates close completely. This usually happens between the ages of 17 and 21.