At what age do you reach skeletal maturity?

Oct 25, 2025 3 min read •

Health Adolescence Human Growth

While the process of bone formation begins in the embryo, most people reach their maximum bone density, known as peak bone mass, between their late 20s and early 30s. This is often confused with the cessation of longitudinal growth, which is one part of reaching full skeletal maturity. Understanding at what age do you reach skeletal maturity is crucial for lifelong bone health and preventing conditions like osteoporosis.

Quick Summary

Skeletal maturity is the process of bones reaching their final size and density, marked by the closure of growth plates. It is influenced by gender, genetics, nutrition, and hormones, and typically occurs in the late teens for males and mid-teens for females, though peak bone mass is achieved slightly later. Assessing bone age is done via X-rays.

Key Points

Closure of Growth Plates: Skeletal maturity involves the fusion of growth plates, ending linear growth.
Gender Differences: Females reach skeletal maturity earlier (13–15) than males (15–18).
Peak Bone Mass: Maximum bone density is achieved later, typically between ages 25 and 30.
Assessment with X-rays: Bone age is determined using X-rays of the hand and wrist.
Multiple Influencing Factors: Genetics, hormones, nutrition, and exercise impact skeletal maturity.
Lifelong Bone Health: High peak bone mass in youth helps prevent osteoporosis later.

The Role of Growth Plates

Growth plates, or physes, are areas of new bone growth found at the ends of the long bones in children and adolescents. They are made of cartilage and are responsible for lengthening the bones. When an individual stops growing in height, it's because these growth plates have hardened into solid bone in a process known as epiphyseal fusion.

Closure timing varies: Growth plates don't all close at the same time. Those in the hands and feet typically close first, while those in longer bones like the femur close later.
Visible on X-rays: On an X-ray, an open growth plate appears as a dark line. Once fused, this line disappears.
Injury vulnerability: During a child's growing years, the growth plates are weaker than the solid bone and are more susceptible to injury.

Differences Between Males and Females

Skeletal maturation differs between males and females due to hormonal influences during puberty. Generally, girls mature earlier.

Skeletal Maturity in Females

Growth plate closure for girls typically occurs between ages 13 and 15, usually a year or two after menstruation begins. Height growth typically stops by age 14 or 15. While linear growth ceases, bone density continues to increase, with about 95% of peak bone mass reached by age 20 and further gains possible until 30. The fastest period of height growth for girls is around 11 to 12 years old.

Skeletal Maturity in Males

For boys, growth plates usually close between ages 15 and 18. Height growth generally stops around ages 16 to 18. Similar to females, peak bone mass is reached later, typically in the late 20s to early 30s. The fastest period of growth for boys is around age 13 to 14.

Factors Influencing Skeletal Maturity

Beyond gender, skeletal maturation is influenced by genetics, hormones, nutrition, and physical activity. Hormones like estrogen are crucial for growth plate fusion. Proper nutrition, especially calcium and vitamin D, and weight-bearing exercise are vital for bone density. Medical conditions can also impact timing.

Assessing Skeletal Maturity

Assessing skeletal maturity often uses X-rays of the hand and wrist, as discussed on {Link: OrthoInfo orthoinfo.aaos.org}. Methods include the Greulich and Pyle Atlas and the Tanner-Whitehouse Method. Other methods like the Risser Sign and Sanders Maturity Scale use the pelvis and hand/wrist respectively and are often used in conditions like scoliosis.

Common Assessment Methods


Assessment Method	Area Examined	Description	Key Indicator	Applicability
Greulich and Pyle Atlas	Left hand and wrist	Compares a patient's X-ray to a series of standardized X-rays of average children at different ages.	Overall bone age based on wrist and hand bones.	Traditional method, though based on older data from a specific population.
Tanner-Whitehouse Method (TW2/TW3)	Left hand and wrist	Assesses the maturity of individual bones, assigning a score to each based on detailed criteria.	Total maturity score is calculated for a more precise bone age estimate.	Considered more objective than the atlas method.
Risser Sign	Pelvis	Uses a pelvis X-ray to track the ossification of the iliac apophysis, which fuses to the pelvic bone.	A scale from 1 (early puberty) to 5 (skeletally mature).	Commonly used for managing adolescent idiopathic scoliosis.
Sanders Maturity Scale	Left hand and wrist	A newer, 8-level scale that assesses bone maturity with better reliability for certain conditions like scoliosis.	Scale of 1 to 8, with 8 being full maturity.	More reliable for assessing peak growth velocity than the Risser sign.

Conclusion

Skeletal maturity, marked by growth plate closure, typically occurs in the mid-to-late teens. However, peak bone mass is reached later, in the late 20s or early 30s. This process is influenced by genetics, gender, hormones, nutrition, and activity. Medical assessment using X-rays provides a more accurate 'bone age' than chronological age alone. Promoting good nutrition and weight-bearing exercise in youth is vital for long-term bone health.

Frequently Asked Questions

Skeletal maturity is the developmental state when the bones in the skeleton have fully grown and ossified, with the cartilage growth plates at the ends of long bones having fused completely. This signifies the end of longitudinal bone growth.

For girls, growth plates typically close around ages 13 to 15. For boys, this usually happens later, between the ages of 15 and 18. The process and timing can vary significantly from person to person.

Peak bone mass is the maximum bone density and strength an individual achieves in their lifetime. It is usually reached in the late 20s or early 30s, after skeletal maturity and the cessation of linear growth.

Skeletal age is determined by a medical professional, such as an orthopedist, using X-rays, most commonly of the left hand and wrist. The X-rays are compared to standard atlases, like the Greulich and Pyle method, to assess the developmental stage of the bones.

No. While linear growth stops when your growth plates close, bone density continues to increase for several years until you reach peak bone mass. Peak bone mass is the maximum density your bones will achieve and is a key determinant of lifelong bone health.

Genetics is a major determinant of skeletal maturity, accounting for a large portion of the variance in peak bone mass and growth timing. Lifestyle factors like nutrition, particularly adequate calcium and vitamin D intake, and weight-bearing exercise are also critical for maximizing bone health during development.

Yes. Skeletal maturity can be delayed by factors such as chronic illness, malnutrition, or endocrine disorders like hypothyroidism or growth hormone deficiency. Conversely, some conditions can accelerate it.

References

Medical Disclaimer

This content is for informational purposes only and should not replace professional medical advice. Always consult a qualified healthcare provider regarding personal health decisions.