Colon and rectum are a part of the digestive system (gastrointestinal system). Colon and rectum form the large bowel. Colon, which forms the majority of the large bowel, is an approximately 1.5 meter long tube-shaped muscular structure. Colon is consisted of seven different segments; caecum, ascending colon, hepatic flexura, splenic flexura, descending colon and sigmoid colon. Rectum is the last 15 cm long part of the large bowel. It starts after the sigmoid colon and ends at the anus. Consumed food is digested and absorbed in the small intestines and then remaining content goes to the colon; water and salt are absorbed here. Remaining content is advanced to the rectum, the last part of the digestive system and stored there until defecated through the anus.