Jejunum and ileum

Organ supplied · Midgut T10–T11

Midgut small bowel from the duodenojejunal flexure to the ileocaecal valve, about 6 m long, supplied entirely by SMA arcades in the mesentery; the terminal ileum shares the ileocolic artery. Visceral pain travels with the lesser splanchnic nerves and is felt around the umbilicus.

Traced from the start

  1. Abdominal aorta
  2. Superior mesenteric artery
  3. Jejunal and ileal arteriesIleocolic artery
  4. Jejunum and ileum

Detail

Supply
Jejunal and ileal arcades (SMA); terminal ileum via ileal branch of ileocolic
Referred pain
Periumbilical, T10–T11 via lesser splanchnic nerve
Meckel's diverticulum
Vitelline duct remnant on the antimesenteric border ~60 cm from the valve, with its own vitelline artery from the SMA

When it goes wrong

Acute SMA occlusion — embolus from AF, recent MI or valve disease

Sudden severe periumbilical pain out of proportion to a soft abdomen, forceful bowel emptying, then peritonitis and lactic acidosis after 6–12 h; CT angiography, embolectomy or resection

Small bowel obstruction that strangulates

Colicky periumbilical pain turns constant with peritonism, fever and rising lactate — ischaemia that mandates immediate surgery

Practise this structure

1 question in the bank tagged Small Bowel.