The rst step in the transanal portion of taTME is the application of the purse string [12, 13]. Care must be taken to have symmetric suture bites which do not extend beyond the outer, longitudi­nal muscle of the rectum as this can inadvertently incorporate tissue that is beyond the scope of dis­section, such as the periprostatic fascia and extra­rectal muscle bers intrinsic to the pelvic oor. However, even with correct purse-string place­ment, entry into the proper TME plane– espe­cially anteriorly– can sometimes be challenging because an often dense structure is encountered, and this can create a barrier to holy plane entry. This specically applies to taTME dissections carried out ≤3 cm of the anorectal ring. Extra­rectal bands of muscle extend from the rectum are properly inserted onto the endopelvic fascia and the preprostatic fascia [14–18]. This is the most pronounced anterior to the rectum and likely represents a composite of the pre-rectal muscle bers of Luschka and the rectourethralis muscle, both of which lie medial to the puborec­talis and the levator ani muscle complex (Fig.31.2). They also contain muscle bers from the conjoined longitudinal muscle of the anal canal. Anteriorly, the rectourethralis and pre­rectal muscle appear fused, becoming quite dened. During the taTME dissection, they appear as broad “vertical” bands of muscle extending from the pre-membranous urethra and posterior lobe of the prostate gland to the anterior rectal wall which makes distinction between the two organs difcult to discern (Fig.31.3). A com- mon error is to assume that these bands of muscle “belong to the rectum” and novice taTME sur­geons will tend to include the rectourethralis muscle and bers of Luschka in the specimen by purposely dissecting too far anteriorly. This is one of the most important factors predisposing to