Densitometric study of developing vertebral bodies.

To define the quantitative aspects of ossification of human fetal spine, we performed a high resolution densitometric study by lateral and postero-anterior scanning of five fetal spines (18-36 weeks of conceptual age) and one spine of a 4-month-old infant. The data were plotted against developmental age for each spine and vertebra. Bone mineral content increased with developmental age, with a peak at the upper lumbar level, in agreement with the ossification pattern of the spine, reported in embryological literature. Bone mineral density (BMD) was unrelated to developmental age, and showed similar trends for each vertebra in all the vertebral columns examined. The changes of BMD seems to be a phenomenon related to individual variability. This study also demonstrates that densitometric techniques may provide useful and interesting information in studies on skeletal development.