[Radiological and histological studies on the growth of lumbar vertebra]

Maturation of the ring apophysis of lumbar vertebral body was studied radiologically and histologically. Investigations on the spine of rats revealed that the vertebral development completed within 24 weeks. Investigations on 22 specimens extracted from human cadavers revealed that the time of appearance of secondary ossification center of the ring apophysis was at 13 years of age, and the time of fusion, however, was radiologically at the age of 17 years, and histologically at 24 years. Further radiological analysis from the adolescent lumbar vertebrae of 754 cases, on the other hand, revealed that the time of appearance was at 14.6 years of age in males, and at 14.0 years in females, while the time of fusion was at 17 years of age in both sexes. Thus, it is concluded that the ring apophysis is an important index of growth of a vertebral body which is conceivably completed at 17 years of age.