Method. A landmark-driven
range built from the documented sequence and timing of hand/wrist skeletal maturation — carpal ossification-center appearance, the metacarpal/phalangeal epiphyses, the thumb adductor sesamoid, epiphyseal capping, and the epiphyseal-fusion sequence (distal phalanges → metacarpals → proximal phalanges → middle phalanges → distal ulna → distal radius). Each finding you mark sets a floor or a ceiling, and the range narrows between adjacent events. This is an aid to skeletal-maturity reasoning,
not a reproduction of the Greulich-Pyle atlas plates — the bone age you report must come from comparing the film against the atlas itself.
No normal/abnormal verdict is produced. Earlier versions of this page compared the estimate to chronological age against a ±2 SD band. That standard-deviation table could not be traced to Greulich & Pyle, the Brush Foundation data, or any other published source, so it has been removed rather than left in place unsourced. The ±2 SD convention itself is real — it is simply not something this tool is equipped to apply.
Reference ages are approximate and sex-specific. Appearance ages follow the Caffey/Kuhn pediatric skeletal-age tables (Tables 17.1–17.2,
Radiology Key, "Skeletal Age") — e.g. thumb adductor sesamoid boys 12 y 8 mo (SD 1 y 6 mo), girls 10 y 1 mo (SD 1 y 1 mo). The hand fusion order (distal phalanges, then metacarpals, then proximal, then middle phalanges) is from the same table and is corroborated by the forensic age-estimation literature (
Demystifying the Radiography of Age Estimation, 2024); note that fusion timing in particular varies substantially between populations, and the exact order is not uniform across published series. The 6–10 year window has fewer events, so resolution there is intentionally wider.
The second and third years are graded on the metacarpal and phalangeal epiphyses, which appear in a fixed order — proximal phalanges, then metacarpals, then middle phalanges, then distal phalanges, with the thumb's distal phalanx earlier and the little finger's middle phalanx last of all (Table 17.1, same source). Each grouped finding here is dated to the
earliest member of its group, so marking it "Present" is a floor the whole group satisfies: proximal phalangeal epiphyses II–IV boys 1 y 4 mo / girls 10 mo; metacarpal epiphyses II–IV boys 1 y 6 mo / girls 1 y; middle phalangeal epiphyses II–IV boys 2 y / girls 1 y 3 mo; distal phalangeal epiphyses III–IV boys 2 y 4 mo / girls 1 y 6 mo; middle phalanx V boys 3 y 3 mo / girls 1 y 10 mo (Table 17.2). Published SDs across these centres are only 3–7 months, which is why this is the best-resolved stretch of the whole scale.
The pisiform is the weakest indicator here and should be weighted accordingly. It is the one centre the Caffey/Kuhn table leaves blank, so its ages come from forensic series instead, and those disagree: boys 9.5 ± 1.7 y and girls 9.5 ± 1.7 y in a North-Karnataka series (
Indian J Forensic Community Med), boys 9.9 y and girls 9.1 y in a Nepalese series with earliest appearance at 10 y and 9 y and universal presence by 13 y (
J-GMC-N), against a textbook window of 9–12 y in boys and 10–12 y in girls. This page uses boys 10 y / girls 9 y 6 mo as a midpoint of that spread; an earlier version used girls 8 y 6 mo, which no published series supports.
The thumb adductor sesamoid does not predict puberty — it confirms it. It becomes visible roughly 0.5 y
after the onset of pubic hair and 0.75 y
after the start of the height spurt, and about 0.7 y
before peak height velocity (
Onat & Numan-Cebeci, Human Biology, a series of 83 girls). Its practical value is that it places the patient on the ascending limb of the growth spurt, not that it forecasts pubertal onset.
Atlas ceiling. The Greulich-Pyle atlas tops out at male standard 31 = 19 y and female standard 27 = 18 y. Once the distal radius is fused the patient is skeletally mature and the bone age is censored at that ceiling — it can be reported as "≥", never as a delay.
Reference only — not a substitute for radiologist interpretation. Bone age has substantial individual and ethnic variation.