During a special roentgenographic survey of the skeletal system in a group of 6- to 7-year-old Japanese children,1 the incidence of spina bifida occulta was found to be considerably higher than that generally reported in the literature. Spina bifida occulta involving the fifth lumbar and/or the first sacral vertebra was present in 95 (58.3%) of 163 children. The present investigation was undertaken to determine whether or not similar high incidences of neural arch defects existed at older age levels in the Japanese population and to obtain data that may permit evaluation of the relation of age and sex to spina bifida occulta in children.
MATERIAL AND METHODS
The number and sex of subjects in each age group studied have been summarized in Table 1.All of these subjects were Japanese who had been residents of Hiroshima City at the time of examination (in 1953). They constituted part of