Detailed and applied anatomy for improved rectal cancer treatment

Abstract

Rectal anatomy is one of the most challenging concepts of visceral anatomy, even though currently there are more than 23,000 papers indexed in PubMed regarding this topic. Nonetheless, even though there is a plethora of information meant to assist clinicians to achieve a better practice, there is no universal understanding of its complexity. This in turn increases the morbidity rates due to iatrogenic causes, as mistakes that could be avoided are repeated. For this reason, this review attempts to gather current knowledge regarding the detailed anatomy of the rectum and to organize and present it in a manner that focuses on its clinical implications, not only for the colorectal surgeon, but most importantly for all colorectal cancer-related specialties.

MRI of rectal cancer—relevant anatomy and staging key points

“…4 Sagittal T2-weighted images before (a) and 5 min after (b) IV administration of a spasmolytic agent (butylscopolamine 20 mg). Notice how the walls of the rectum and small bowel are much better defined due to limited peristalsis reflection is located most commonly 1 to 4 cm below S1-S2 and corresponds to the upper limit of the rectum [21,22]. It is not easily identified.…”

“…The venous drainage takes place through both an outer muscularis plexus that extends longitudinally from the anterior peritoneal reflexion down to the levatior ani, and an inner submucosal plexus which runs through the whole extension of the rectum and continues down to the anus [22]. Both plexus anastomose superiorly give rise to the superior rectal vein, draining the roughly upper 2/3 of the rectum into the portal circulation through the inferior mesenteric vein [22]. Inferiorly, the inner plexus becomes the inferior rectal vein.…”

“…A middle rectal vein may be found in about 32.6%, usually unilaterally and rarely accompanied by a middle rectal artery. Inferior and middle rectal veins drain roughly the distal 1/3 of the rectum into the systemic circulation through the internal iliac vein [22,25].…”

“…6 b) [ 19 , 20 ]. The posterior peritoneal reflection is located most commonly 1 to 4 cm below S1–S2 and corresponds to the upper limit of the rectum [ 21 , 22 ]. It is not easily identified.…”

“…The main route is the superior rectal artery, which is the continuation of the inferior mesenteric artery when it crosses the left common/internal iliac artery (Fig. 7 a) [ 22 ]. The middle rectal arteries are inconsistent (present in 36–57% of cases) and highly variable.…”