Origin and morphometry of the inferior mesenteric artery

Abstract

Introduction The inferior mesenteric artery (IMA) represents a key vessel supplying the left colon and rectum. Its anatomical variability, including the site of origin, caliber, and relationship to the abdominal aorta, is clinically important for surgery and interventional radiology. A precise understanding of these parameters reduces intraoperative risks and improves surgical outcomes. The origin, topography, course, anastomoses, and distribution of the colic arteries show high variability. As Mayo stated, “no two individuals have identical colonic blood vessels.” A precise anatomical understanding of these variations is essential in vascular and colorectal surgery, as well as in accurate radiological interpretation. Material and methods The inferior mesenteric artery (IMA) was studied in 209 cases using multiple anatomical and imaging approaches: 49 dissected adult cadavers, 7 eviscerated infradiaphragmatic organ blocks, 69 simple aortic angiographies, and 94 angio-CT scans. Results The IMA most frequently originated from the anterior aspect of the abdominal aorta at the level of L3 (62% of cases), but variations were observed from L2 to L4. The artery’s caliber at its origin ranged from 2.1 to 4.9 mm, with a mean of 3.2 mm. The distance from the superior mesenteric artery varied between 22 and 65 mm. Multiple branching patterns were noted, including common trunks with the left colic artery in 11% of cases. The origin of the IMA was located between the upper half of the L2 vertebra and the lower edge of L4. Its distance from the renal arteries ranged from 43.9 to 73.3 mm. The distance to the aortic bifurcation was 30–40 mm. The IMA originated most frequently on the left anterior surface of the abdominal aorta. Its diameter varied from 2.7 to 4.0 mm, and its length ranged from 0.5 to 5.0 cm, depending on the point of origin of its first collateral branch. Conclusions The IMA shows significant anatomical variability in its origin and morphometry. Awareness of these variations is crucial for surgical planning, vascular interventions, and accurate imaging diagnosis. Our results provide additional data supporting the integration of anatomical and radiological methods in preoperative evaluation. Significant anatomical variability of the IMA exists. Differences in findings among authors are attributed to the number of cases studied, measurement methods, and potential geographic or ethnic vascular characteristics.