Corpus: Superior mesenteric artery

The superior mesenteric artery is a major branch of the abdominal aorta, arising immediately after the celiac trunk. This makes it the second unpaired branch of the abdominal aorta following the celiac trunk.

The superior mesenteric artery originates from the aorta at the level of the first lumbar vertebra. It travels anteriorly and inferiorly, passing behind the neck of the pancreas and the splenic vein. The following structures are situated between the superior mesenteric artery and the aorta:

• Left renal vein
• Horizontal part of the duodenum
• Uncinate process of the pancreas

The superior mesenteric artery is accompanied by the superior mesenteric vein, which runs parallel to it.

After passing the neck of the pancreas, the superior mesenteric artery divides into several important branches:

• Inferior pancreaticoduodenal artery: Gives rise to anterior and posterior branches that anastomose with branches of the superior pancreaticoduodenal artery, forming a vascular ring around the duodenum and the head of the pancreas.
• Jejunal and ileal arteries: Supply blood to the jejunum and ileum.
• Middle colic artery: Divides into right and left branches to form vascular arcades at the transverse colon, which anastomose proximally with the right colic artery and distally with the left colic artery through the Riolan and Drummond anastomoses.
• Right colic artery: Forms vascular arcades along the ascending colon and anastomoses proximally with the ileocolic artery and distally with the middle colic artery.
• Ileocolic artery: Supplies the distal ileum, the proximal ascending colon, and branches into the anterior and posterior cecal arteries and the appendicular artery, which supply the cecum and the vermiform appendix.

The superior mesenteric artery supplies arterial blood to:

• The duodenum and pancreas
• The jejunum and ileum (small intestine)
• The cecum and vermiform appendix
• The ascending colon
• The proximal two-thirds of the transverse colon

The superior mesenteric artery can be affected by conditions such as mesenteric artery stenosis, which may lead to compromised blood flow to the intestines. Additionally, compression of the left renal vein between the superior mesenteric artery and the abdominal aorta can cause the "nutcracker phenomenon", leading to various symptoms due to impaired venous return from the kidney.