Mesorectal fascia

Last revised by Dr Vikas Shah on 21 Oct 2021

The mesorectal fascia is a layer of connective tissue enclosing the perirectal fat that surrounds the rectum. It is an important anatomical structure in rectal cancer staging, as it forms the circumferential resection margin for the non-peritonealised portion of the rectum.

  • location: envelopes the perirectal fat which surrounds the rectum within the pelvis
  • boundaries: extends from the beginning of the rectum to levator ani
  • contents: perirectal fat which contains the superior rectal artery and branches, superior rectal vein and tributaries, and lymph nodes and vessels

The mesorectal fascia begins at the rectosigmoid junction where it blends with the connective tissue of the sigmoid mesentery. It extends to the end of the rectum at levator ani. Laterally it extends around the rectum and perirectal fat and becomes contiguous anteriorly with the rectovesical fascia (Denonvilliers fascia). Posteriorly it fuses with the presacral fascia (Waldeyer fascia). Note that a variable circumference of the rectum is enveloped by the mesorectal fascia, owing to the fact that the peritoneum reflects off the anterior aspect of the middle and upper thirds of the rectum (see Figure 1).

  • encloses the perirectal fat which in turn contains:
    • superior rectal artery and branches
    • superior rectal vein and tributaries
    • lymph nodes and vessels

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Cases and figures

  • Figure 1: illustration
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