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At what age do clavicles stop growing?: An in-depth look

3 min read

The clavicle, or collarbone, is the last bone in the body to complete its growth, a process that can extend into a person's mid-twenties. In contrast to other long bones that finish growing much earlier, understanding at what age do clavicles stop growing is important for interpreting adolescent injuries and forensic age estimation.

Quick Summary

The clavicle, the last bone in the body to complete its development, continues to grow well into early adulthood. This is due to the late fusion of the medial growth plate, a process that typically concludes between 21 and 25 years of age. Variations exist between genders, with males often experiencing slightly longer growth periods.

Key Points

  • Last Bone to Fuse: The clavicle is the final bone in the human body to complete its growth, often finishing around 25 years of age.

  • Prolonged Medial Growth: The medial growth plate, near the breastbone, is the last part of the clavicle to fuse, a process occurring between 21 and 25 years.

  • Continued Early Adult Growth: Studies confirm measurable clavicle growth continues in both men and women well past their teens, though at a slowing rate.

  • Gender Variations: Males typically have a slightly longer period of substantial growth after skeletal maturity compared to females.

  • Forensic Age Indicator: Due to its late fusion, the medial clavicular physis is a reliable tool for forensic experts estimating the age of young adults.

  • High Remodeling Potential: The long growth period gives the clavicle a high capacity for remodeling, which influences treatment decisions for adolescent fractures.

In This Article

The Clavicle: An Unusual Growth Pattern

Unlike most other long bones, the clavicle is unique in its developmental process. It is the first bone to begin ossification (bone formation) during the fifth to sixth week of gestation but the very last one to fully fuse. This prolonged growth is a key characteristic that has implications for both clinical medicine and forensic science. The extended growth period is primarily driven by the growth plate at the medial end of the bone, where it connects to the sternum.

The Role of Growth Plates in Clavicle Maturation

Growth plates, or physes, are soft cartilage areas located near the ends of long bones where new bone is added during childhood and adolescence. While many growth plates close and harden into solid bone by the end of puberty, the clavicle's medial physis remains active for significantly longer.

  • Early Development: The clavicle's primary growth centers start developing early in the womb.
  • Intramembranous vs. Endochondral Ossification: The clavicle develops through a mix of both types of bone formation, a rare trait for a long bone.
  • Delayed Fusion: The secondary ossification center, which is responsible for most of the bone's length growth, does not appear until late adolescence (around 18-20 years) and does not fully fuse until the mid-twenties.

Timeline of Clavicle Growth

Scientific studies have charted the timeline of clavicle growth, confirming that measurable changes continue long after the main adolescent growth spurt. For instance, a 2020 study using serial radiographs of young adults found continued growth potential even in the 20-25 age range.

  • Substantial Adolescent Growth: Both male and female clavicles show significant growth between the ages of 12 and 19.
  • Continued Early Adult Growth: For men, measurable growth continues well into the 20-25 age range, with one study showing an average growth of 1.7 mm/year in this period.
  • Later Fusion: The medial clavicular physis typically does not fuse until 23 to 25 years of age.

Gender Differences in Clavicle Growth

While the overall pattern is similar, studies show distinct differences in the pace and duration of clavicle growth between males and females.

Feature Male Clavicle Growth Female Clavicle Growth
Skeletal Maturity (Approx.) 16 years 14 years
Growth After Maturity Continues for about 10% of total length Continues for about 5% of total length
Growth Rate (16-19 yrs) Approx. 3.2 mm/year Approx. 2.2 mm/year
Growth Rate (20-25 yrs) Approx. 1.7 mm/year Approx. 0.2 mm/year
Final Fusion Often up to 25 years or later Often up to 25 years or later

Clinical and Forensic Implications

Knowing when the clavicle stops growing is important in several medical and legal contexts.

  • Forensic Age Estimation: Since the medial clavicular physis is one of the last growth plates to fuse, its state of development is a reliable indicator of age in young adults. Forensic experts can use computed tomography (CT) scans to assess the degree of ossification and estimate a person's age.
  • Clavicle Fractures: The extended period of growth means that fractures of the clavicle in adolescents and young adults have greater potential for remodeling compared to fractures in older individuals. In fact, the "remarkable remodeling potential" of the clavicle has long been a factor in decisions for non-operative treatment of pediatric fractures.
  • Treatment Decisions: Orthopedic surgeons may consider the remaining growth potential when deciding between operative and non-operative management of displaced clavicle fractures in young people. Significant remodeling potential in young male adolescents, for instance, might favor a more conservative approach.

Conclusion

While most of the body's skeletal growth is completed by the end of the teenage years, the clavicle is a notable exception. Its medial growth plate is the last in the body to ossify and fuse, a process that can continue until approximately 25 years of age. This means that individuals may experience subtle but measurable growth in their collarbones throughout early adulthood. This unique developmental pattern is not just a biological curiosity; it has practical applications in forensic science and influences clinical decisions regarding fracture management in young patients. For these reasons, understanding at what age do clavicles stop growing provides crucial insights into human skeletal development and maturity.

Growth and Development of the Clavicle

For more information on the intricate process of bone formation, see the Wikipedia article on Ossification.

Frequently Asked Questions

Yes, unlike many other long bones, the clavicle continues to grow well beyond puberty. Its medial growth plate is the last in the body to fully fuse, a process that can continue until a person is around 25 years old.

The clavicle's medial growth plate, or physis, is a layer of cartilage at the end of the bone near the sternum (breastbone). This is where most of the clavicle's longitudinal growth occurs and is the last part of the bone to harden.

Yes, research indicates some gender differences. For example, a 2019 study showed that significant growth remains after skeletal maturity in males (about 10% of total length) compared to females (about 5%). Males may also experience measurable growth slightly later than females.

In forensic and medical contexts, the fusion of the medial clavicular epiphysis is a key indicator for estimating age in young adults. By examining CT scans and classifying the stages of ossification, experts can reliably estimate if a person is over 18 or 21, which is useful in legal cases.

The prolonged growth of the clavicle means it has a remarkable capacity for remodeling, which aids in healing fractures. This is why many adolescent clavicle fractures can be successfully treated without surgery, relying on the body's natural remodeling process.

Given that the clavicle can continue to grow and remodel until the mid-twenties, it is possible for some young adults to experience mild, intermittent sensations or aches in the area. However, any persistent or significant pain should be evaluated by a doctor to rule out other issues.

After the growth plates fuse, the soft cartilage is replaced by solid bone, and the bone is no longer capable of growing in length. At this point, the clavicle has reached its final, adult length.

References

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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.