The intestinal wall is divided into plasma layer, intrinsic muscle layer, superficial intrinsic muscle layer, submucosal layer, mucosal layer and mucosal muscle layer from the outside to the inside. The intestinal wall is relatively thin, and the specific thickness of the intestinal wall varies from location to location. The intestinal wall is generally thicker in the rectum, about 0.8-1 cm, the thickness of the ascending colon and transverse colon is about 0.6-0.4 cm, and the colon in the ileocecal region is generally about 0.5 cm. Therefore, if endoscopic treatment is done for this thickness of the intestinal wall, it is necessary to pay high attention to prevent the possibility of perforation. For polyps that may appear in the intestinal wall, most of them occur in the mucosal layer or mucosal muscle layer. If there are smooth muscle tumors, they usually occur in the submucosal layer, and some may reach the lamina propria.