The jejunum is arbitrarily defined as the proximal two-fifths of the small intestine and is, on average, about 3 m in length.
Compared to the ileum, the jejunum has more valvulae conniventes and fewer folds per unit length. Like the ileum, the normal jejunal wall thickness is less than 3 mm. The jejunum has a larger diameter compared to the ileum.
Together with the ileum, the jejunum lies in the free margin of the mesentery as a continuation of the duodenum.
- jejunal branches from the superior mesenteric artery
- corresponding veins which drain into the superior mesenteric vein
- lymphatics drain into the superior mesenteric lymph nodes
- sympathetic: lateral horn cells of spinal segments T9 and T10
- parasympathetic: vagus nerve augments the peristaltic activity
Small bowel follow-through examination (SBFT)
Jejunum has a delicate feathery appearance and is located in the left upper abdomen.