Estimating projected height using skeletal age

Projected height for a child older than two years can be determined by extrapolating the child's growth along the current channel to the 18- to 20-year mark. For children with delayed or accelerated growth, using the skeletal age (bone age) rather than the chronologic age to determine the projected height channel provides more accurate assessment of projected height. In the example above, the 10-year-old male has a skeletal age of 8 years; the child is 49 inches tall (<3^rd percentile for chronologic age [point A], but 25^th percentile for skeletal age [point B]). The projected height is the 25^th percentile height for a 20-year-old (point C): 68 inches.