Presacral fascia

The presacral fascia or Waldeyer's fascia, lines the anterior aspect of the sacrum, enclosing the sacral vessels and nerves. It continues anteriorly as the pelvic parietal fascia, covering the entire pelvic cavity. It has been erroneously described as the posterior aspect of the mesorectal fascia. These two fascias are in fact, separate anatomical entities. During rectal surgery and mesorectum excision, dissection along the avascular aveolar plane between these two fascias, facilitates a straightforward dissection and preserves the sacral vessels and hypogastric nerves.

The presacral fascia is limited postero-inferiorly, as it fuses with the mesorectal fascia, lying above the levator ani muscle, at the level of the anorectal junction. The colloquial term, among colo-rectal surgeons, for this inter-fascial plane, is known as the "holy plane" of dissection first coined by Heald RJ.

The mesorectal fascia, also known as the fascia propria or the pelvic visceral fascia, has been originally described as the fascia recti in Waldeyer's publication, Das Becken. Fascia recti is also a term commonly used among French surgeons to describe the mesorectal fascia. Confusingly, fascia recti is described in some anatomy books, referring to the fascia of the rectus abdominis muscle.

Identification and preservation of the presacral fascia is of fundamental importance in preventing complications and reducing local recurrences of rectal cancer. Hence attention to this anatomy is essential in contemporary rectal surgery.