乙状结肠是结肠终末部分，通常位于盆腔中，上在左髂嵴平面与降结肠相连，下在第三骶椎平面与直肠相接，长约40～50cm，因呈“乙”状弯曲而得名。

• 《人体解剖学》，北医大协和医大联合出版社，2001年

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 + -oid). 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.