The

inferior mesenteric vein In human anatomy, the inferior mesenteric vein (IMV) is a blood vessel that drains blood from the large intestine. It usually terminates when reaching the splenic vein, which goes on to form the portal vein with the superior mesenteric vein (SMV) ...

begins in the

rectum The rectum is the final straight portion of the large intestine in humans and some other mammals, and the Gastrointestinal tract, gut in others. The adult human rectum is about long, and begins at the rectosigmoid junction (the end of the s ...

as the superior rectal vein (superior hemorrhoidal vein), which has its origin in the

hemorrhoidal plexus The rectal venous plexus (or hemorrhoidal plexus) surrounds the rectum, and communicates in front with the vesical venous plexus in the male, and the vaginal venous plexus in the female. A free communication between the portal and systemic venous ...

, and through this plexus communicates with the middle and

inferior hemorrhoidal vein Inferior may refer to: * Inferiority complex * An Anatomical terms of location#Superior and inferior, anatomical term of location * Inferior angle of the scapula, in the human skeleton *Inferior (book), ''Inferior'' (book), by Angela Saini * ''The ...

s. The superior rectal vein leaves the

lesser pelvis The pelvic cavity is a body cavity that is bounded by the bones of the pelvis. Its oblique roof is the pelvic inlet (the superior opening of the pelvis). Its lower boundary is the pelvic floor. The pelvic cavity primarily contains the reproducti ...

and crosses the left

common iliac vessels Common iliac vessels are composed of: * The common iliac artery (arteria iliaca communis) * The common iliac vein In human anatomy, the common iliac veins are formed by the external iliac veins and internal iliac veins. The left and right com ...

with the

superior rectal artery The superior rectal artery (superior hemorrhoidal artery) is an artery that descends into the pelvis to supply blood to the rectum. Structure The superior rectal artery is the continuation of the inferior mesenteric artery. It descends into the ...

, and is continued upward as the

References

Veins of the torso Rectum {{circulatory-stub