This chart depicts bone age as compared with chronological age in boys. The normal range is represented by 2 standard deviations (SD) above and below the mean (white area on this chart). Bone age is delayed if it is below this threshold (blue area), and advanced if it is above this threshold (green area). In clinical practice, a bone age that is 20 percent below or above the chronological age is considered abnormal. These data are based on the Brush Foundation Study, performed in well-nourished White children in the 1930s and 1940s.
Reference:
- Greulich WW, Pyle SI. Radiographic Atlas of Skeletal Development of the Hand and Wrist, 2nd Edition, Stanford, CA: Stanford University Press and London, UK: Oxford University Press, 1959.
Data from: Gaskin CM, Kahn SL, Bertozzi JC, Bunch PM. Skeletal development of the hand and wrist. Oxford University Press, New York 2011. p.8.
