抄録
Tha development of anal sphincter muscles is a most important prognostic factor in children with imperforate anus. In order to evaluate the development of anal sphincter muscles, CT examination was carried out and the area of muscles distribution in inferior pelvic aperture was calculated with micro-computer. Our results are as follows ; 1. In the low type anomalies which blind pouch was below I line, muscle distribution was as wide as in the normal cases. 2. Whereas, in the high type anomalies which blind pouch was on M line, muscle distribution was narrower. Furthermore, in the case which blind pouch was on P-C line, muscle distribution was extremely limitted. 3. A ratio of the area of muscle distribution to that of inferior pelvic aperture may be a valuable index for evaluating the development of anal sphincter muscles.
