The adjacent layers of the right-side colon and its clinical significance

Abstract

Objective The autopsy method was used to study the adjacent layers related to right-side colon, which provided a reliable applied anatomical basis for accurate membrane anatomic right hemin-colectomy. Methods Five corpses fixed in formalin (four males and one female) were anatomically observed on the adjacent layers of right-side colon. Results The right-side colon can be divided into three fusion fascia regions according to surrounding adjacent layers: the Toldt′s fusion fascia region, the pancreaticoduodenal fusion fascia region, and the omental-transverse colon fusion fascia region. (1) The right Toldt′s fusion fascia region: It is derived from the ileocecal, ascending colon and the its dorsal mesentery fused to primary posterior peritoneum. The cranial border of the right Toldt′s fusion fascia region is the lower edge of the duodenal ring. The medial border is the right margin of the superior mesenteric vein. The right and caudal border is the rim between the ileocecal, ascending colon and posterior peritoneum. On the dorsal side of the right Toldt′s fusion fascia region, there are two layers: posterior peritoneal continuation (primary posterior peritoneum) and urogenital stratum. They form three spaces include the right Toldt′s fusion fascial space, anterior renal space and posterior renal space. (2) The pancreaticoduodenal fusion fascia region: It is derived from the fusion fascia formed by the hepatic flexure of the colon and its dorsal mesentery and propria fascia of the pancreaticoduodenal. The cranial border is the duodenal bulb which gastric omentum adhere to. The caudal border is the lower edge of the duodenal ring. The lateral border is the lateral edge of the duodenal ring. The medial border is the right edge of the greater omentum (The anatomy mark is the Right Gastroepiploic Vein). On the dorsal side of the pre-pancreaticoduodenal fusion fascia region, there are three layers: pancreaticoduodenal, posterior peritoneal continuation (primary posterior peritoneum) and urogenital stratum. They form four fusion fascial spaces include the pre-pancreaticoduodenal space, retro-pancreaticoduodenal space and anterior renal space and posterior renal space. The right Toldt′s fusion fascial space continues to the cranial and separated by the pancreaticoduodenal layer into the pre-pancreaticoduodenal space and retro-pancreaticoduodenal space. The anterior superior pancreaticoduodendal vein generates from the head of pancreas, stretch across the pre-pancreaticoduodenal space, and joins to the Henle trunk in the mesentery. (3) The omental-transverse fusion fascia region: This region from the right edge of the omentum, to the left, consisting of the right margin of the omentum and anterior layer of transverse mesenteric fascia. This region forms three spaces from the ventral side to the dorsal side, which is omental bursa, the peri-pancreatic space and the retro-pancreatic space. The third layer of omentum covers the ventral surface of the pancreas. The fourth layer of omentum surrounds the body and tail of the pancreas and the spleen from the dorsal side, There is a peripancreatic space between the third layer and the fourth layer of the omentum. The fourth layer of omentum fuse to the avascular zone of the transverse mesocolon tightly , and separates with it at the lower edge of the pancreas, the space between them is the retro-pancreatic space. Conclusion Based on the theory of embryo development, the relationship between adjacent layers of the right semicolon was studied by anatomical method. Well understanding of these layers and their interfused fascia spaces will facilitate safe, accurate, and effective right hemicolectomy. Key words: Colon; Anatomy; Right-side colon; Adjacent layer; Applied anatomy