Editing Bone age (section)

==== Greulich and Pyle atlas ====
In the United States, bone age is usually determined by comparing an x-ray of the patient's left hand and wrist to a set of reference images contained in the Greulich and Pyle atlas.<ref name=":4" /><ref name=":1" /><ref name=":6" /><ref name=":0" /> Drs. William Walter Greulich and Sarah Idell Pyle published the first edition of their standard reference atlas of x-ray images of the left hands and wrists of boys and girls in 1950.<ref name=":12">Greulich WW, Pyle SI: ''Radiographic Atlas of Skeletal Development of the Hand and Wrist'', 2nd edition. Stanford, CA: Stanford University Press, 1959.</ref> The Greulich and Pyle atlas contains x-ray images of the left hands and wrists of different children deemed to be good models of the average appearance of the bones of the hand at a given age. The atlas has a set of images arranged in chronological order by age for males ranging from 3 months to 19 years and for females ranging from 3 months to 18 years in varying intervals of 3 months to 1 year.<ref name=":6" /><ref name=":7">{{Cite journal |last1=Prokop-Piotrkowska |first1=Monika |last2=Marszałek-Dziuba |first2=Kamila |last3=Moszczyńska |first3=Elżbieta |last4=Szalecki |first4=Mieczysław |last5=Jurkiewicz |first5=Elżbieta |date=2021-08-23 |title=Traditional and New Methods of Bone Age Assessment-An Overview |journal=Journal of Clinical Research in Pediatric Endocrinology |volume=13 |issue=3 |pages=251–262 |doi=10.4274/jcrpe.galenos.2020.2020.0091 |issn=1308-5735 |pmc=8388057 |pmid=33099993}}</ref>

Images in the Greulich and Pyle atlas came from healthy white boys and girls enrolled in the Brush Foundation Study for Human Growth and Development between the years 1931 and 1942.<ref name=":1" /><ref name=":4" />

To assign a bone age to the patient under review, a radiologist compares the patient's hand and wrist x-ray to images in the Greulich and Pyle atlas. Assessment of the carpals, metacarpals, and phalanges are used to find the closest match in the atlas; the chronological age of the patient in the atlas becomes the bone age assigned to the patient under review.<ref name=":6" /> If a patient's x-ray is found to be very close in appearance to two contiguous images in the atlas, then an average of the chronological ages in the atlas may be used as the patient's bone age, although some evaluators choose to interpolate the closest age while others report a range of possible bone ages.<ref name=":8" />

A drawback associated with the Greulich and Pyle method of assessing bone age is that it relies on x-ray imaging and therefore requires exposing the patient to ionizing radiation. Further, there can be moderate levels of variability in the bone ages assigned to the same patient by different assessors.<ref name=":7" /> Other downsides are that the atlas has not been updated since 1959 and the images in the atlas were acquired from healthy white children living in Cleveland, Ohio in the 1930s and 1940s and therefore may not yield accurate bone age assignments when applied to non-white patients or unhealthy children.<ref name=":0" /><ref name=":1" /><ref name=":7" />[[File:Bones_of_the_hand_and_wrist_used_for_bone_age_estimation_in_the_Tanner-Whitehouse_method.svg|thumb|267x267px|Bones of the hand and wrist used for bone age estimation in the Tanner-Whitehouse method.]]