One hundred and twenty cases of imperforate anus, including 70 cases of high type and 50 cases of low type, were retrospectively analyzed in respect to the associated vertebral anomalies. Various kinds of vertebral anomalies were associated with 28.3% of the cases. The association rate was 37.1% of high type and 16.0% of low type. It was obvious that the high type has significantly more chance to accompany the vertebral anomalies than the low type anomalies. Some specific types of imperforate anus, such as rectal agenesis, rectovestibular fistula, rectovesical fistula, and anal stenosis, had high association rate than others. The most vulnerable protion of the vertebral column was sacral region. Lower lumber and middle thoracic spines were the next to it. High type anomalies occasionally involved multiple spines. The vertebral deformities in high types frequently advanced to congenital scoliosis. The vertebral anomalies accompanied with high types were severer than with low ones. From the classification of accompanied vertebral anomalies, it was suggested that critical period of vertebral anomalies in high type imperforate anus would be earlier stage of prenatal period than that in low type anomalies.
