Fig. 10
From: MRI anatomy of the rectum: key concepts important for rectal cancer staging and treatment planning
Sagittal images of a male individual without rectal cancer (a, b) demonstrating the superior rectal artery (black arrows in a) and superior rectal vein (white arrows in a) that form the main blood supply of the rectum. The dashed arrows in b show the small venous structures that form the presacral venous plexus situated outside the mesorectal compartment behind Waldeyer’s fascia. The sagittal image in c shows a different case where the presacral venous plexus is severely dilated (black arrowheads)