Bone Age in Girls Aged 4 Years — Greulich-Pyle Hand and Wrist X-Ray Reference
Bone age assessment using a left-hand and wrist radiograph is a standard method for evaluating skeletal maturation in children. The Greulich-Pyle atlas provides sex-specific reference standards by comparing observed ossification patterns against atlas plates representing average skeletal development. In girls aged 4 years, this assessment is particularly relevant in the workup of growth disorders, precocious or delayed puberty, and endocrine conditions.
Expected Ossification Centers and Skeletal Findings
By 4 years of age in girls, several carpal ossification centers are typically well established. The capitate and hamate, the earliest carpal bones to ossify (appearing around 3 and 6 months of age, respectively), should be clearly visible and showing progressive growth. The triquetral ossification center, which typically appears between 2–3 years, is generally present and visible by this age. The lunate, expected to appear around 3–4 years, should be emerging or present in most girls by age 4.
The distal radial epiphysis, which typically ossifies around 1 year of age, is well established by age 4 and shows continued growth and modeling. The distal ulnar epiphysis is not yet expected at this age, as it typically appears between 5–7 years. Ossification of the scaphoid, trapezium, and trapezoid is beginning to emerge in some girls around this period, though these centers most commonly appear between 4–6 years and may not yet be fully visible in all 4-year-olds.
- Capitate and hamate: present and growing
- Triquetral: typically present
- Lunate: present or just appearing
- Distal radial epiphysis: well ossified
- Scaphoid, trapezium, trapezoid: may be just appearing
- Distal ulnar epiphysis, pisiform, thumb sesamoid: not yet expected
Clinical Pearls
Girls’ skeletal maturation is consistently ahead of boys’ by approximately 1–2 years throughout childhood, a difference already apparent at this age. The standard deviation for bone age at 4 years is roughly ±12–18 months, meaning a range of approximately 2.5–5.5 years may still fall within normal limits. A bone age significantly advanced beyond this range should prompt consideration of precocious puberty, congenital adrenal hyperplasia, or exogenous androgen exposure. Conversely, a markedly delayed bone age may suggest growth hormone deficiency, hypothyroidism, or constitutional delay of growth and puberty.
A key interpretive pitfall at this age is over-relying on a single carpal center for age assignment; the overall pattern of ossification across multiple bones should guide the assessment rather than any one center in isolation. Reference: Greulich WW, Pyle SI. Radiographic Atlas of Skeletal Development of the Hand and Wrist. 2nd ed. Stanford University Press, 1959.
