In the past two decades, the problems in observation on the internal structures of anal area and pelvic floor were resolved by using ultrasound, CT and MRI (Magnetic Resonance Imaging), whereafter, research on pelvic floor became a hot spot. The conventional ideas formed in hundreds of years have been continuously questioned, because of those new anatomical physiology signs and new concepts. Understanding of these new signs and new concepts is helpful for colorectal surgeons to investigate anal abnormity, functional disorder of anus and rectum, stages of anorectal cancer, spreading routes and classification of anal fistula, procedures of rectal cancer resection, procedures of sphincterectomy and sphincter reserving surgery, procedures of anal reconstruction, etc. It also may help urologists and gynaecologists investigate new type of surgeries on pelvic floor.
Under the support of national natural science foundation, Chinese investigators denied two misconceptions that the levator ani muscle has the function of elevating anus and anal area consists of five layers [1 - 6], indicated the errors in XXXX’s defecation theory and the part of anal canal in Gray’s anatomy, which is an “outstanding work” in the research of pelvic floor. In order to improve the research of pelvic floor in China, this article is intended to introduce those important new signs found and new concepts raised by domestic and foreign investigators, and analyze the potential clinical significance.
1. Imaging anatomy and new physiological concepts of the levator ani muscle
The levator ani muscle, which is the largest muscle in pelvic floor, is considered as the originator of defecation, urination and childbirth. The real function of the levator ani muscle is hard to observe since it is located on the bottom of pelvic floor. In 1739, XXXX emphasized the difficulty in further researching, because the muscles in pelvic floor are interlaced with each other. In 1899, XXXX indicated that there were maximum researches on the levator ani muscle, but minimum understanding on it [7]. After 1989, ultrasound, CT , MRI and other imaging techniques can be used to display the levator ani muscle [2, 5].
Primary Morphous It means the primary morphous of the levator ani muscle at decubitus position. Western investigators described it as three different shapes, including tray-shaped inferior facet, funnel-shaped inferior facet and fornix-shaped superior convex. Chinese investigators proved that, at decubitus position, the levator ani muscle is tray-shaped in anterior pelvic floor, funnel-shaped in middle pelvic floor and fornix-shaped in posterior pelvic floor [3]. These new signs resolved the debate about its primary morphous.
Morphologic change It is one of the patterns of manifestation of the physiological functions of the levator ani muscle and there are two different hypotheses. In 1980, XXXX thought that pelvic floor, anus and the levator ani muscle were lifted up during defecation [8]. In 1997, Guo Maolin thought that above three structures were descended at the same time during defecation, but lifted up together while contracting the anus [1]. In 2007, Guo Maolin et al verified their previous hypothesis and denied XXXX’s hypothesis using CT defecography [4].

肛区和盆底解剖生理新概念及其临床意义
最近20年间，超声、CT和MRI（磁共振成像）先后突破了肛区和盆底内部结构的观察难题，盆底随之成为一个研究热点。由于新解剖生理学征象和新概念不断涌现，数百年来形成的传统观念受到了持续的冲击。了解这些新征象和新概念，有助于肛肠外科医生研究肛门畸形、肛门直肠功能失调、肛门直肠肿瘤分期、肛瘘传播路径与分类、直肠癌切除术术式、括约肌切除术和保留术术式、肛门重建术术式等，也有助于泌尿科和妇产科医生研究新的盆底外科手术。
在国家自然科学基金的支持下，我国的研究者否定了提肛肌提肛和肛区分5层两大错误观念[1 - 6]，并指出了XXXX排便理论和格氏解剖之肛管部分的错误所在，为盆底研究做出了一项“outstanding work”。为了推进我国的盆底研究，本文将系统介绍国内外研究者发现的重要新征象和提出的重要新概念，并对其潜在的临床意义进行粗浅的分析。
一、提肛肌的影像解剖和生理新概念
提肛肌（the levator ani muscle）是最大的盆底肌，有人认为它是排便、排尿和分娩的发动者。由于提肛肌位于盆底内部，其真实功能难以观察。1739年XXXX指出由于盆底肌交织在一起，研究难度很大；1899年XXXX指出提肛肌是研究最多，同时又是了解最少的肌肉[7]。1989年之后，超声、CT和MRI等影像技术逐渐具备了显示提肛肌的潜力[2, 5]。
初始形态 系指卧位时提肛肌的原始形态，西方学者将其描述为盆状下凹、漏斗状下凹和穹窿状上凸3种不同的形态；我国研究者证实，在卧位时，提肛肌在前盆底为盆状，在中盆底为漏斗状，在后盆底为穹窿状[3]。这一组新征象化解了人们对其初始形态的争议。 
形态变化 系提肛肌生理功能的表现形式之一，有2种不同的猜想。1980年XXXX认为排便时盆底、肛门和提肛肌三者均上提[8]；1997年郭茂林认为排便时三者一同下降，仅当缩肛时三者才会一同上提[1]。2007年郭茂林等用CT排便造影证实了早期猜想，否定了XXXX猜想[4]。