ObjectiveTo investigate the anatomical mark of attachment edge in mesorectal tail and the effect of its morphologic distribution in performing total mesorectal excision (TME). MethodsThe gross specimens of 220 consecutive patients with the middlelower rectal cancer were collected by a group of surgeons.Patients were divided into two groups.①Group in saving sphincter. Ⅰa group, low anterior resection (LAR): 81 patients with lesions between 5 and 6 cm from the anal verge underwent LAR ; Ⅰb group, anterior resection (AR): 68 patients with lesions between 7 and 8 cm from the anal verge underwent AR.②Group in resecting sphincter. Abdominoperineal resection (APR): 71 patients with lesions between anal verge and 5 cm from the anal verge underwent APR. Results①The circular edge of mesorectal tail is attached on rectal wall of 1 cm above anal hiatus of levators,which level parallels the lower margin of lower rectal cancer.In order to reset distal rectal wall of 2 and 3 cm,undergoing LAR must avoid injuring rectal wall when dissecting muscular vessel of rectum continue along the levators fascia to the anal hiatus.②The attachment morphology of mesorectal tail is a circular flake and not circular linear in shape. There are a little of fat tissue between posterior rectal wall and mesorectal tail,the length of its longitudinal attachment is (1.269±0.171) cm (81 cases in LAR group and 71 cases in APR gourp).Because the distal resective margin of rectum undergoing AR just locate in area of flake attachment of mesorectum, removing mesorectum around rectal wall must avoid injuring the rectal wall. Conclusion The mesorectal tail is a circular flake and attaches on rectal wall of 1.0 cm above anal hiatus of levatorani.Undergoing LAR or AR must avoid to injure rectal wall,which may result in leakage of anastomosis when removing mesorectal tissuce around distal rectal wall.
