Growth plates, also known as epiphyseal plates, are areas of cartilage found near the ends of long bones in children and adolescents. These specialized regions determine an individual’s final adult height. They serve as sites where new bone tissue is generated, contributing to the lengthening of bones during growth years. Understanding their status is important for assessing remaining growth potential.
Understanding Growth Plates
These structures are essentially “growth factories” where specialized cells continuously divide and produce new cartilage. This new cartilage then hardens into bone through a process called ossification, causing the bone to lengthen. This lengthening process is responsible for the increase in height observed throughout childhood and adolescence. Growth plates remain active during periods of rapid growth, often referred to as growth spurts, and typically fuse or close once an individual reaches full skeletal maturity.
Medical Assessment of Closure
The definitive method for determining if growth plates have closed is through medical imaging, specifically X-rays. Doctors examine X-ray images for the presence or absence of growth plates. On an X-ray, an open growth plate appears as a distinct dark line or gap at the end of the bone, representing unossified cartilage. As growth progresses, this line thins and disappears as cartilage is replaced by bone, indicating closure.
To assess overall skeletal maturity and growth potential, doctors commonly take an X-ray of the left hand and wrist. This area is preferred as it contains numerous small bones and growth plates, providing a comprehensive picture of bone development for comparison against standardized atlases of bone age. While X-rays of other areas like the ankle or knee can show growth plate status in those bones, the hand and wrist X-ray is typically used for a general assessment of skeletal age. Self-assessment or external signs are not reliable indicators of growth plate closure.
Implications of Closed Growth Plates
Once growth plates have completely fused, linear height growth ceases. This means long bones can no longer lengthen, and an individual has reached adult height. For girls, growth plates typically close around ages 14 to 16, while for boys, closure usually occurs between 16 and 19 years old, though individual variations exist. Closure is gradual, with different bones fusing at different times; for instance, hand and foot growth plates often close earlier than those in longer bones like the femur.
While linear growth stops, other bodily changes, such as muscle development and weight changes, can continue. People often seek to know if their growth plates are closed for various reasons, including understanding their final adult height potential or for medical considerations related to certain treatments or procedures. For example, in some medical conditions, delaying growth plate closure can be a therapeutic goal to increase adult height.