Anatomy and Embryology of the Colon, Rectum, and Anus

Abstract

The dentate line represents a true division between embryonic endoderm and ectoderm.• The location of the anterior peritoneal reflection is highly variable and can be significantly altered by disease such as rectal prolapse. • The right and left ischioanal space communicate posteriorly through the deep postanal space between the levator ani muscle and anococcygeal ligament. • The junction between the midgut (superior mesenteric artery) and the hindgut (inferior mesenteric artery) leads to a potential watershed area in the area of the splenic flexure. • There is a normal, three-stage process by which the intestinal tract rotates during development beginning with herniation of the midgut followed by return of the midgut to the abdominal cavity and ending with its fixation.

Assessing the Impact of Primary Tumour Location on Survival After Resection of Colorectal Liver Metastases: A Propensity Weighted Retrospective Cohort Study

“…Neoadjuvant chemoradiotherapy plays a pivotal role in the treatment of a significant proportion of rectal cancers. This may contribute to the favourable course they appear to display in CRLM [25]. Although our results here show that adjuvant therapy for primary and neoadjuvant therapy for liver metastases are associated with poorer survival, this is likely confounded by more advanced stages and greater extent of liver disease that necessitates these therapies.…”

The Mesentery—Past, Present, and Future

“…Given this, the mesorectum, mesogastrium, mesopancreas (or mesoduodenum), and right and left mesocolon were misnomers. 12…”

“…During this period, the peritoneal model of abdominal anatomy continued as the focus of the first chapter of many reference texts in surgery. 12 13 In effect, the surgical technique went in one direction; anatomy held fast to the peritoneal model of the abdomen.…”

“…Despite this being the case the idea of the mesorectum remained (until recently) a misnomer to anatomists. 12 Indeed it often continues to be described as such in the anatomical chapter of reference texts of colorectal surgery. 12 13…”

“…12 Indeed it often continues to be described as such in the anatomical chapter of reference texts of colorectal surgery. 12 13…”