Bone Age at 2.5 Years: Boy and Girl Hand X-Ray Reference
These reference radiographs show the typical appearance of the hand and wrist of a 2.5 year old boy and a 2.5 year old girl for bone age assessment. In the toddler period the hand radiograph gains detail rapidly. Epiphyses of the phalanges and metacarpals ossify in a predictable order, and the distal radial epiphysis becomes established. Girls stay consistently ahead of boys, often by a few months of skeletal age.
2.5 year old boy hand x-ray

In boys the distal radial epiphysis is now visible and growing, while the epiphyses of the proximal phalanges appear first, followed by the metacarpals and the middle and distal phalanges. The triquetrum usually ossifies later in boys, closer to the third birthday.
2.5 year old girl hand x-ray

In girls most phalangeal and metacarpal epiphyses appear earlier than in boys. The triquetrum often becomes visible around the second birthday in girls, and the distal radial epiphysis is clearly established and enlarging.
What to look for at 2.5 years
- Distal radial epiphysis is established and enlarging
- Phalangeal epiphyses appear in sequence: proximal, then middle and distal
- Metacarpal epiphyses ossify during this period
- Triquetrum appears around 2 years in girls and closer to 3 years in boys
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 28 Months and Bone Age at 3 Years. Browse every age point in the complete bone age atlas by age.