Jejunum

Dr Jeremy Jones et al.

The jejunum is arbitrarily defined as the proximal two-fifths of the small intestine and is, on average, ~300 cm in length.

The primary method of evaluation of the small bowel is small bowel follow-through examination (SBFT). On SBFT, the jejunum has a delicate feathery appearance, and is located in the left upper abdomen.

Compared to the ileum, the jejunum has more valvulae conniventes and fewer folds per unit length. Like the ileum, normal jejunal wall thickness is less than 3 mm. The jejunum has a smaller diameter (average 2.5 cm) compared to the ileum (3 cm).

Relations

Together with the ileum, the jejunum lies in the free margin of the mesentery as a continuation of the duodenum.

  • arterial supply: jejunal branches from the superior mesenteric artery
  • venous drainage: corresponding veins which drain into the superior mesenteric vein

Lymphatic vessels drain into the superior mesenteric lymph nodes.

  • sympathetic: lateral horn cells of spinal segments T9 and T10
  • parasympathetic: vagus nerve augments peristaltic activity
Abdominal and pelvic anatomy
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Article Information

rID: 23082
Section: Anatomy
Synonyms or Alternate Spellings:

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