The small intestine consists of three parts: the duodenum, the jejunum, and the ileum. The entire small intestine is about 6 m long (range: 4.6­9 m). The duodenum is about 25 cm long (the term "duodenum" means 12, suggesting that it is 12 inches long). The jejunum, constituting about two-fifths of the total length of the small intestine, is about 2.5 m long; and the ileum, constituting three-fifths of the small intestine, is about 3.5 m long. Two major accessory glands, the liver and the pancreas, are associated with the duodenum.
