from this experience , and from surgical anorectal anatomy demonstrating fusion between the visceral and the somatic tube at 5 cm from the anal verge , it is concluded that proctectomy with coloanal anastomosis is a safe procedure for mid-rectum adenocarcinoma , but that a majority of low-lying cancers ( greater than or equal to 6 cm ab ano ) must be treated by abdominoperineal excision .
C0227423
anal verge
C0003461
ano