The
sigmoid colon (
pelvic colon) is the part of the large intestine that is closest to the
rectum and
anus. It forms a loop that averages about 40 cm in length. The loop is typically shaped like a Greek letter sigma (ς) or Latin letter S (thus
sigma + ). This part of the colon normally lies within the
pelvis, but on account of its freedom of movement it is liable to be displaced into the
abdominal cavity.