sigmoid colon sigmoid colon the sigmoid colon (or pelvic colon) is the part of the large intestine that is closest to the rectum and anus. it forms a loop that averages about 35–40 centimetres (14–16 in) in length. the loop is typically shaped like a greek letter sigma (ς) or latin letter s (thus sigma + -oid). this part of the colon normally lies within the pelvis, but due to its freedom of movement it is liable to be displaced into the abdominal cavity. sigmoid colondrawing of colon seen from front(sigmoid colon coloured blue)front of abdomen, showing surface markings for liver, stomach and large intestinedetailsprecursorhindgutpart oflarge intestinesystemdigestive systemarterysigmoid branches of inferior mesenteric arterynerveinferior mesenteric ganglia and sacral nerveidentifierslatincolon sigmoideummeshd012809ta98a05.7.03.007ta22987fma14548anatomical terminology major parts of thegastrointestinal tract upper gastrointestinal tract mouth esophagus stomach duodenum lower gastrointestinal tract small intestine jejunum ileum large intestine sigmoid colon rectum anus