Where is the colon?

The colon is located in the right iliac fossa. Connect rectum at the level of the third sacral vertebra. Colon is divided into ascending colon, transverse colon, descending colon and sigmoid colon, most of which are fixed on the posterior abdominal wall. The arrangement of the colon is similar to the English letter "M" and surrounds the small intestine. The diameter of the colon gradually decreases from 6 cm at the beginning to 2.5 cm at the end of the sigmoid colon, which is the narrowest part of the colon cavity.

Extended data

The course of the disease changed greatly. In 65,438+02 cases (65,438+07%), the ascending branch of the artery and vein of the left colon was shorter and finally reached the splenic flexure. The splenic flexure marginal artery of colon is mainly formed by the end of the right branch of middle colonic artery or the end of the left branch of accessory middle colonic artery. At this time, the left branch of the middle colon artery is long, which passes through the splenic flexure and coincides with the ascending branch of the left colon artery, forming a marginal artery at the starting point or at 1/3 of the ascending colon. The overall external diameter of this anastomosis is small, which is 0.8-1.0mm. We call the vascular external diameter of the anastomosis less than1.0 mm as poor anastomosis.

There were 20 cases (28%) in the splenic flexure of colon, and the external diameter of the anastomotic orifice of marginal artery was less than 65438±0.0mm, and the number of long and short branches of terminal artery distributed from marginal artery to splenic flexure of colon was less than that in other areas. At this time, the blood supply of colonic splenic flexure is poor. In addition, the anastomosis between ascending branch of ileocolic artery and descending branch of right colon artery was poor 14 cases, accounting for about 20%. Poor anastomosis between the ascending branch of the right colonic artery and the right branch of the middle colonic artery 1 1 case, accounting for about 15%. There were 20 cases (25%) with poor anastomosis between the left branch of the middle colonic artery and the ascending branch of the left colon.

There were 49 cases (7000 cases) with no anastomotic branch between the superior rectal artery and the lowest sigmoid artery, so the blood supply at the junction of sigmoid colon and rectum was poor. The average vascular diameter at the anastomosis of marginal artery was 65438 0.4 mm.