Skeletal maturity is an important factor in scoliosis because progression will slow or end (unless scoliosis is severe) when vertebral growth is finished.
Appearance of a growth plate at the top of the pelvis are important indicators of skeletal maturity define as Risser sign. The Risser sign is seen as a white line across the top of the pelvis on the scoliosis x-ray.
On a scale of 5, it gives a measure of progression of ossification. The appearance of the Risser sign is divided into five stages. A Risser 1 is when the line extends 25% of the distance across the pelvis, Risser 2 is halfway across, Risser 3 is 75% of the way, and Risser 4 is all the way across. The separation between this line and the rest of the pelvis eventually disappears and the child is considered to be a Risser 5, indicating skeletal maturity.