"median sacral artery (branch of the distal abdominal aorta) may constitute a minor supply to the posterior aspect of anorectal junction; however, it is clinically relevant in that it can potentially cause bleeding in surgical procedures in this area."
"At the level of the S3 vertebral body, the sigmoid colon loses its mesentery and becomes the rectum. As the rectum passes in front of the sacrum, it takes a concave shape anteriorly. It is sinuous with three alternating bends laterally. In the distal sigmoid colon, the taenia coli flatten and fuse to form an outer longitudinal muscular layer. Thus, unlike the remaining large intestine, the rectum does not have the distinctive haustra or epiploic appendages. The rectum is approximately 15 cm long."
"posteriorly: presacral fascia, S3-S5, coccyx, median sacral artery, superior rectal vessels, sacral sympathetic chain"
"median sacral artery (branch of the distal abdominal aorta) may constitute a minor supply to the posterior aspect of anorectal junction; however, it is clinically relevant in that it can potentially cause bleeding in surgical procedures in this area."