What is Tanner-Whitehouse?
Tanner-Whitehouse (TW) is one of the two main methods used to determine bone age (the other being Greulich-Pyle). While Greulich-Pyle matches the X-ray holistically with an atlas, Tanner-Whitehouse follows a more analytical route: each of certain bones in the hand and wrist is given a separate score according to its level of maturity. These scores are summed to obtain a maturity score, and this score is converted into a bone age.
The current version of the method is TW3; it contains updated references based on more recent population data. Because the TW approach scores bone by bone, it is considered more standard and reproducible, but its assessment is more time-consuming than Greulich-Pyle.
Difference from Greulich-Pyle
Both methods serve the same purpose — to express skeletal maturity as an “age” — but go about it by different routes. Greulich-Pyle is fast and gives a practical result in the hands of an experienced reader; but because it relies on holistic matching, the difference between assessors can be slightly greater. Tanner-Whitehouse, by scoring each bone separately, is more systematic and highly reproducible, but takes more time.
Which method is used often depends on institutional habit and purpose. The two methods can give slightly different bone ages in the same child; so using the same method consistently in a child’s follow-up is important for interpreting the trend correctly.
What is it used for?
The bone age obtained with Tanner-Whitehouse, just as with Greulich-Pyle, is used to measure maturation and to predict adult height. Whether bone age is behind or ahead of calendar age provides information about the child’s remaining growth potential and can be turned into an adult-height estimate with methods such as Bayley-Pinneau.
In modern applications, AI-assisted systems can automate both the Greulich-Pyle and the Tanner-Whitehouse logic, producing fast and consistent bone-age estimates. Even so, whichever method is used, the result is not a diagnosis on its own; it is a piece of data that should be interpreted by a doctor together with growth velocity, height and the clinical picture.
Which should be preferred?
In practice, which method is used often depends on the institution’s habit, the assessor and the purpose. When a quick assessment is needed and an experienced reader is available, Greulich-Pyle is a practical choice; when research or a more standard and reproducible result is needed, Tanner-Whitehouse comes to the fore. Both methods are valid and widely used; one does not definitively replace the other.
For families, what really matters is not the name of the method but how the bone age is interpreted. Whichever method is used, the result is not a decision tool on its own; it is assessed together with the child’s growth velocity, height, pubertal findings and overall health. Using the same method consistently in a child’s follow-up is important for reading change over time correctly. In short, Tanner-Whitehouse and Greulich-Pyle are two different but complementary answers to the same question — “how mature is this child’s skeleton?” Whichever is chosen, bone age is a tool; it gains meaning when combined with the child’s growth story and should not be seen as a verdict tool on its own.