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A single X-ray of a child’s hand and wrist that shows how mature their skeleton is, and whether that is in line with their age. It helps explain a child’s growth and guide the timing of orthopaedic treatment.
A bone age test — also called a bone age study, or a skeletal age X-ray — estimates how mature a child’s bones are. The result is given in years, and compared with the child’s actual age.
Growing bones have growth plates near each end: bands of softer tissue where new bone is laid down. On an X-ray they show as dark lines. As a child matures, the bones change shape in predictable ways and the growth plates thin, then close. The hand and wrist contain many small bones and growth plates in one view, which makes them a good place to read this.
Children grow fastest in the first two years, steadily through childhood, and again in the growth spurt around puberty. Bone age shows whether a child’s bones are maturing in line with their age along that path.
Bone age is compared with the child’s calendar age. A difference is not a diagnosis on its own; it is read alongside height, growth rate and family pattern.
| Bone age behind | About the same | Bone age ahead | |
|---|---|---|---|
| What it suggests | Bones maturing more slowly than usual for that age | Bones maturing in line with age | Bones maturing faster than usual for that age |
| Common reasons | A late bloomer, often running in the family. Less often: a hormone problem, or a long-term illness | Normal growth. Also typical of children who are short because their parents are | Early puberty, or being overweight. Less often: a hormone problem |
| Usually next | Monitoring growth; hormone tests if growth is slow | Reassurance, or further tests if growth has slowed | A check for signs of early puberty; hormone tests where needed |
A difference of up to a year or so either way is common in healthy children. Larger differences, or a growth rate that is slowing, are the ones more likely to need looking into.
A bone age test is not urgent. These signs are a reason to see your child’s doctor soon rather than wait:
Call us on +65 8849 0677 for bone or limb concerns. For the first three, your child’s paediatrician is usually the right first step.
Call +65 8849 0677The left hand is the convention. Most people are right-handed, so the left hand is less likely to have been injured, and using the same hand every time lets results be compared.
The result is a best match, not an exact measurement. Two careful readers can differ by several months, and one bone age on its own says less than how a child’s height changes over time.
The standard atlas has limits. The most widely used one was built from American children many decades ago. Children from other populations, including many Asian children, can mature on a somewhat different timetable, so the result is interpreted with that in mind.
What the assessment answers is whether a child’s bones are maturing in line with their current age. It is not used here to predict how tall a child will be.
Most results fit a healthy child growing on their own timetable. Measuring height every few months shows whether growth stays on track.
If the bone age or the growth pattern suggests something may be affecting growth, blood tests may be recommended to rule out underlying reasons, such as a thyroid or other hormone problem.
Where the X-ray, blood tests and growth pattern point to a hormone problem or early puberty, the next step is a paediatric endocrinologist, who diagnoses and treats those conditions. That is not done here.
For scoliosis, leg-length differences and limb alignment, knowing whether a child is still growing, and how mature the skeleton is for their age, helps decide whether and when to brace, monitor or treat.
Bone age tests are carried out by any of the clinic’s orthopaedic surgeons: Dr Kelvin Tan, Dr Jeffrey Tan, Dr Arul Murugan and Dr Lim Heng Hing. The X-ray is taken and read at the same clinic.
Dr Arul Murugan previously served at KK Women’s and Children’s Hospital, and consultations with him are also available in Tamil or Hindi.
Yes. A hand X-ray uses a very small dose of radiation, less than the amount everyone receives from natural background radiation in a single day.
No. There is no fasting and no injection. Rings, watches and bracelets on the left hand are removed before the X-ray.
Often not. Many children with a younger bone age are late bloomers, maturing on their own timetable. Whether it needs looking into depends mainly on how fast they are growing.
It is not used for that here. The test shows whether your child’s bones are maturing in line with their current age, and measuring height every few months shows whether growth stays on track.
It is the standard convention. The left hand is less often injured in right-handed children, and using the same hand every time means results can be compared.
No. You can book directly, and the X-ray is done here.
The X-ray is done here, and the doctor goes through the result with you.
