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What happens to the growth plates when skeletal maturity is reached?

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Internal structure of a human long bone — bone A long bone of the human body, showing a magnified cross section of the interior.

When skeletal maturity is reached, the growth plates (also known as epiphyseal plates) fuse and disappear. This process marks the end of longitudinal bone growth.12

The closure of these plates is driven by various hormonal influences, particularly sex hormones. Estrogen, in particular, plays a key role in triggering the fusion of the epiphyses, thereby ending the growth of long bones. While other hormones like testosterone and thyroid hormones also influence the timing of skeletal development, their effects ultimately lead to the same result: the cessation of growth through epiphyseal closure. Once this fusion occurs, the cartilage that previously allowed for bone lengthening is replaced by bone, and further linear growth is no longer possible.231