Branching Pattern of Inferior Mesenteric Artery in a Black African Population: A Dissection Study

Background. Branching pattern of inferior mesenteric artery (IMA) and pattern of vascular supply to the left colon and rectosigmoid areas, though important during colorectal surgery, display interethnic variations. Further, these regions have notable vascular “weak points” reported to be highly susceptible to ischemic colitis. This study aimed at evaluating the branching pattern of IMA in a black African population. Materials and Methods. Fifty-seven formalin-embalmed cadavers (28 Male, 27 Female) were studied. The length, branching pattern, and diameter of IMA at its origin were recorded. Results. IMA mean length and diameter at origin were 30.57 ± 10.0 mm and 4.10 ± 0.9 mm, respectively. IMA most frequently branched into left colic artery and a common sigmoid trunk in 23 cases while the classical branching pattern was observed in only 7 cases. Colic marginal artery was absent at the splenic flexure and sigmoid colon in 7 and 5 cases, respectively. Arc of Riolan was observed in 9 cases. Conclusion. Branching pattern of IMA shows variations from the previously reported cases which might help account for some of the untoward outcomes observed following colon surgery. An angiographic study to further delineate functionality of the arterial anastomoses in this region is recommended.