Acromial Apophyseal Growth Plate Status in an 11-Year-Old Boy
Yes, the acromial apophyseal growth plate is expected to be open in a healthy 11-year-old boy. 1
Normal Developmental Timeline of the Acromion
Based on MRI studies of normal skeletal development, the acromial process follows a predictable maturation sequence:
Formation of Secondary Ossification Centers
- Acromial secondary ossification centers begin forming at age 10 years, which is significantly earlier than previously reported in older literature 1
- At age 11, your patient would be in the early phase of secondary ossification center development, with the growth plate still open 1
Fusion Timeline
- Fusion of the acromial primary and secondary ossification centers begins at age 14 years 1
- Fusion is generally complete after age 16 years 1
- Therefore, an 11-year-old boy is approximately 3 years away from even the beginning of fusion 1
Clinical Implications
Expected Imaging Findings
- The cartilaginous precursor of the acromion conforms to the final shape of the structure even before ossification 1
- The chondro-osseous interface becomes progressively more lobulated as development proceeds 1
- On MRI, you may see the early appearance of secondary ossification centers, but the growth plate itself remains open 1
Important Distinction from Other Growth Plates
This timeline differs from other anatomical sites. For comparison, the calcaneal apophysis begins fusion at age 12 and is complete in 78% of children by ages 14-15 2, making the acromial growth plate relatively later in its closure timeline.