目的:通过研究直肠系膜的形态学特点和范围来认识直肠系膜全切除（TME）的理论依据。方法:上海交通大学医学院附属瑞金医院对24具尸体的盆腔进行解剖。结果:在直肠及周围脂肪周围存在两个相互独立的结构，一个是直肠侧后方的脏筋膜，另一个是直肠前方的Denonvilliers筋膜，它们共同组成了直肠周围的环状筋膜，Denonvilliers筋膜并不能构成直肠系膜的前界。结论:TME改善预后的原因并不在于其切除平面为肿瘤难以逾越的“Holy plane”，而是在于其完全切除了“直肠腔室”。

Objective:To clarify the basis of total mesorectal excision by studying the morphology of the mesorectum. Methods:Twenty-four pelvises (12 male,12 female) harvested from embalmed cadavers were studied by dissectiodn. Results:There were two different fascial envelopes around the perirectal fat:a posterolateral envelope made up of the visceral pelvic fascia and an anterior membrane made up of the Denonovilliers fascia.Denonvilliers’ fascia couldn’t be regarded as anterior part of mesorectum. Conclusion:The improved prognosis achieved by total mesorectal excision lies in the excision of rectal compartment en bloc.