What Is a Bone Age Scan?

A bone age scan, an X-ray of a child's left wrist and hand, helps doctors determine skeletal maturity. By comparing the X-ray to a reference atlas of X-rays of healthy children, doctors verify whether bone age, or skeletal age, matches chronological age.

Reasons for a scan

• Your doctor may order a bone age scan for your child if there is a concern for either advanced growth or growth delay, which may indicate glandular or systemic disorders, such as growth hormone deficiency or digestive tract disease.

Normal bone age

• A normal bone age should be within 10 percent of a child's chronological age. For example, for a 10-year-old child, a bone age between 9 and 11 years would be considered normal.

Delayed bone age

• A bone age outside the lower norm may be a sign of a more serious condition, such as hypothyroidism. However, doctors will first rule out familial short stature (due to genetics) or constitutional growth delay ("late-bloomers"), which are both variants of normal growth patterns.

Advanced bone age

• A bone age outside the upper norm may indicate a condition such as central precocious puberty (early puberty). Obesity may contribute to advanced skeletal growth, and according to an October 2009 study published by the American Heart Association, advanced bone age may indicate hypertension in children.

Reassurance for parents

• Most commonly, though, a bone age scan is obtained to forecast growth potential in shorter children. Often, with this simple X-ray, a doctor can reassure parents that their child is growing normally.