Jejunum
The jejunum lies between the duodenum and the ileum and is considered to start at the suspensory muscle of the duodenum, a location called the duodenojejunal flexure. The division between the jejunum and ileum is not anatomically distinct due to the fact that in adult humans, the small intestine is usually 6-7m long, about two-fifths of which (2.5 m) is the jejunum.
Ileal interposition
In addition to sleeve gastrectomy procedure, the connection between the stomach and the duodenum is closed off from the level of the second segment of the duodenum. While preserving the last 30 cm part of the small intestine, a 170 cm segment of ileum is prepared and connected to the first segment of the duodenum, which is at the end of the stomach. The other end of the ileum segment is connected to the proximal part of the small intestine. Thus, distal part of the small intestine is ‘’interposed’’ between proximal part of the small intestine and the stomach. Since duodenum and the proximal part of the small intestine is disabled, a partial bypass is in question. Patients who undergo this operation achieve better weight and blood sugar control, but face anemia (iron deficiency) risk because of the bypass procedure.