Bone Age at 12 Months: Boy and Girl Hand X-Ray Reference
These reference radiographs show the typical appearance of the hand and wrist of a 12 month old boy and a 12 month old girl for bone age assessment. In infancy the hand and wrist radiograph shows only the earliest signs of skeletal maturation. The capitate and hamate are usually the only carpal bones visible at this stage, and the overall picture changes quickly from month to month, which makes precise reference images especially valuable.
12 month old boy hand x-ray
In boys the capitate and hamate are typically the only ossified carpal bones at this age. The distal radial epiphysis has usually not yet appeared, and the phalangeal epiphyses are not ossified. Boys mature slightly more slowly than girls, so findings that look delayed against a mixed reference can still be normal for a boy.
12 month old girl hand x-ray
Girls run ahead of boys from the very beginning of skeletal development. At this age the capitate and hamate are clearly visible, and the distal radial epiphysis may already be starting to ossify. Early phalangeal epiphyses can appear sooner than in boys of the same chronological age.
What to look for at 12 months
- Capitate and hamate are the first carpal bones to ossify and should be visible
- Distal radial epiphysis appears around the first birthday, earlier in girls
- Phalangeal and metacarpal epiphyses are largely not yet ossified
- Assessment relies on the size and shape of the capitate and hamate
How to use these reference images
Obtain a PA radiograph of the left hand and wrist and compare it side by side with the reference image for the matching sex. If the patient’s radiograph looks more mature, move to an older reference; if it looks less mature, move to a younger one. The best match gives the estimated bone age, which you can then combine with chronological age and current height to predict adult height.
Neighbouring ages: Bone Age at 10 Months and Bone Age at 14 Months. Browse every age point in the complete bone age atlas by age.