The colon is composed of two parts: the colon and the rectum. The colon starts from the lower right abdomen of the body and is divided into the cecum, ascending colon, hepatic flexure, transverse colon, splenic flexure, descending colon and sigmoid colon in a clockwise direction in the abdominal cavity. The cecum is the beginning of the large intestine and is located in the lower right abdomen, continuing upward to the ascending colon, which is named because its lower end is the enlarged blind end. The left side of the cecum is connected to the end of the ileum through the ileocecal valve. The ileocecal valve contains muscle and consists of two half-moon shaped folds above and below. The ileocecal valve is like a door that prevents the contents of the small intestine from flowing too quickly into the large intestine so that food can be fully digested and absorbed in the small intestine. When the digested and absorbed food residues in the small intestine enter the cecum, the ileocecal valve can prevent the food residues in the cecum from flowing back to the small intestine. The appendix is attached to the posterior medial wall of the cecum and is a thin tube, about 6-8 cm long. The common term “appendicitis” is not actually an inflammation of the cecum itself, but rather an “appendicitis”. Now we know that the appendix and the appendix are two different structures, so in the future, when you encounter patients with appendicitis, do not wrongly accuse the appendix again. The ascending colon is about 15 cm long and is a direct continuation of the cecum upward, turning to the left in the right upper abdomen, below the liver, and moving into the transverse colon. The hepatic flexure of the colon is located between the ascending and transverse colon and is the bend on the right side of the colon, called the hepatic flexure of the colon because the bend is located below the liver. The transverse colon is about 50 cm long and is located in the upper abdomen, below the stomach, and travels laterally below the spleen and continues in the splenic flexure of the colon. The splenic flexure of the colon is located between the transverse and descending colon and is the left side of the bend of the colon, which is called the splenic flexure of the colon because it lies below the spleen. The descending colon is about 25 cm long and travels down the left side of the abdomen to the left lower abdomen to continue in the sigmoid colon. The sigmoid colon is located in the left lower abdomen and is named because of its “sigmoid” shape, with a total length of about 20-40 cm. The rectum is located in the posterior part of the pelvis (lower abdomen), in front of the sacrum, with a total length of about 15 cm. The rectal cavity is lined with three semilunar bulges called transverse rectal folds. The end of the rectum is connected to the anal canal, and the dentate line is the dividing line between the rectum and the anal canal. For men, the rectum is preceded by structures such as the bladder, prostate and vas deferens; for women, the rectum is preceded by the uterus and vagina. Therefore, sometimes a doctor may examine the prostate in order to examine the prostate in a male patient or the uterus in a female patient through rectal palpation.