Anatomical Location of the Inferior Mesenteric Vein
The inferior mesenteric vein (IMV) is located on the left side of the body.
Anatomical Position and Course
The IMV follows a characteristic left-sided course through the abdomen:
- The IMV is best identified by its location behind or to the left of the duodenojejunal flexure 1
- It continues inferiorly to the left of the fourth stage of the duodenum, lying in the left anterior pararenal space 1
- Superiorly, the IMV drains into either the splenic vein, superior mesenteric vein, or the splenoportal junction 1
Relationship to Adjacent Structures
The left-sided position of the IMV has important clinical implications:
- In 91% of cases, the IMV trunk is accompanied by arteries only in its lower and middle portions (by the inferior mesenteric artery and left colic artery), while its terminal part is separated from the artery 2
- The IMV's position relative to the left colic artery at the IMA root level varies, with 77.3% showing an adjacent relationship (Type A) and 22.7% showing a distant relationship (Type B) 3
- The mean distance from the IMA root to the IMV is approximately 27.9 ± 9.21 mm 4
Clinical Significance
Understanding the left-sided location of the IMV is critical for:
- Surgical planning during colorectal procedures, where inadvertent ligation of collateral vessels around the IMV root can compromise blood supply to the left colon 5
- Radiologic evaluation, where the IMV can be measured behind or to the left of the duodenojejunal flexure (normal diameter 3-6 mm; >9 mm suggests portal hypertension) 1
- Three-dimensional preoperative imaging to map the anatomical relationship between the IMV, IMA, and left colic artery 3, 4