The portal vein is formed by the merging of the splenic vein, which brings blood from the spleen, and the superior mesenteric vein, which brings blood from the intestines. Smaller veins from the ...

When you have mesenteric venous thrombosis (MVT), you have a blood clot in a vein around where your intestines attach to your belly. The clot most often forms in a vein called the "superior ...