The location of the colon is relatively long and widespread in the body. The colon begins in the ileocecal region, which is located in the lower right abdomen of the body, then goes up the posterior abdominal wall to the lower part of the liver, then turns to the left and evolves into the transverse colon. When the transverse colon reaches the lower part of the spleen, which is the splenic flexure of the colon, it naturally turns downward along the left side of the abdomen down into the pelvis and into the rectum. In the case of a lesion in the colon, pain can occur in all of the locations just mentioned. Sometimes the transverse colon is relatively short and is located in the upper abdomen; sometimes it is long and can enter the pelvic cavity. If there is a bloody stool or a change in the stool pattern, thin stool, or an increase in the number of stools, it is considered to be a lesion in the colon, and a colonoscopy combined with an abdominal CT examination is needed.