Before the "mesorectal" theory was proposed, the traditional anatomy believed that the "pelvirectal space" belonged to the anal canal and perirectal space, which was independent of the rectal structure, located on both sides of the rectum, above the levator ani, and below the peritoneal reflexion, and was composed of a large amount of fatty tissue filling. With the development of the theory of membrane anatomy and the clarification of the concept of "rectal mesentery", combined with the author's clinical experience, we found that the above-mentioned fat is actually the fat within the mesorectum, as well as the fat tissue of lateral lymph nodes (LLN) such as the internal iliac lymph nodes (No.263) and obturator lymph nodes (No.283) on both sides of the rectal mesentery, rather than the so-called fat tissue within the interstitial space. Therefore, the author believes that the pelvirectal space does not exist. In the anatomical location equivalent to the pelvic rectal space, there is the "superior levator ani space" based on the membrane anatomy theory. From the pelvirectal space to the superior levator anal space, it reflects our further understanding of the anatomy of the rectal mesentery.

Before the "mesorectal" theory was proposed, the traditional anatomy believed that the "pelvirectal space" belonged to the anal canal and perirectal space, which was independent of the rectal structure, located on both sides of the rectum, above the levator ani, and below the peritoneal reflexion, and was composed of a large amount of fatty tissue filling. With the development of the theory of membrane anatomy and the clarification of the concept of "rectal mesentery", combined with the author's clinical experience, we found that the above-mentioned fat is actually the fat within the mesorectum, as well as the fat tissue of lateral lymph nodes (LLN) such as the internal iliac lymph nodes (No.263) and obturator lymph nodes (No.283) on both sides of the rectal mesentery, rather than the so-called fat tissue within the interstitial space. Therefore, the author believes that the pelvirectal space does not exist. In the anatomical location equivalent to the pelvic rectal space, there is the "superior levator ani space" based on the membrane anatomy theory. From the pelvirectal space to the superior levator anal space, it reflects our further understanding of the anatomy of the rectal mesentery.