Jejunum

The jejunum is the middle section of the small intestine between the duodenum and the ileum. The change from the duodenum to the jejunum is usually defined as the duodenojejunal flexure (junction) and is attached, and thus "hung up", to the stomach by the ligament of Treitz. 

If the jejunum is impacted by blunt force the emesis reflex (vomiting) will be initiated. The jejunum and the ileum are suspended by mesentery which gives the bowel great mobility within the abdomen. It also contains circular and longitudinal smooth muscle which helps to move food along by a process known as peristalsis.