The jejunum is the second segment of the small intestine, connecting the duodenum to the ileum. It comprises roughly two-fifths of the small bowel length and is responsible for the majority of nutrient absorption. On ultrasound, the jejunum is not commonly the focus of examination but may be evaluated when bowel pathology is suspected. In small bowel obstruction, dilated, fluid-filled jejunal loops may be visible, and the valvulae conniventes (circular folds) of the jejunum can sometimes be seen as thin, closely spaced folds within the dilated lumen. In Crohn disease, jejunal involvement may show wall thickening, hyperemia, and surrounding mesenteric inflammation.
Sonography Term