Superior Mesenteric Artery

arteria mesenterica superior

The superior mesenteric artery supplies the entire midgut from the second part of the duodenum to the proximal two-thirds of the transverse colon, representing the largest single splanchnic artery. Acute occlusion of the SMA from thrombosis or embolism produces massive small bowel ischaemia — a surgical emergency with mortality over 70 percent even with prompt treatment, as the entire midgut becomes ischaemic rapidly given the lack of adequate collaterals.

Region: Abdomen

Anatomical Data

Origin, Insertion & Supply

Origin	Anterior abdominal aorta at L1, immediately below the coeliac trunk

Clinical Relevance

Clinical Notes

Acute SMA occlusion presents with sudden severe periumbilical pain disproportionate to physical findings — pain out of proportion is the classical teaching phrase. Cardiac embolism (atrial fibrillation, recent myocardial infarction) and atherosclerotic thrombosis are the most common causes. CT angiography confirms the diagnosis and the window for revascularisation before irreversible bowel necrosis is 6 hours. Chronic SMA stenosis produces intestinal angina — crampy postprandial pain and weight loss from fear of eating.

Pathology

Common Injuries & Conditions

Acute SMA Occlusion

Embolic or thrombotic obstruction producing massive midgut ischaemia with pain disproportionate to physical findings, requiring emergency revascularisation or bowel resection with mortality over 70 percent.