Branching Pattern of Superior Mesenteric Artery and its Variations

Abstract

Background: Superior mesenteric artery (SMA) originates at L1 level as a ventral branch of abdominal aorta. It supplies the derivatives of midgut which extends below the opening of major duodenal papillae in the 2nd part of the duodenum till the junction between the right 2/3rd left 1/3rd of the transverse colon. After its origin, it descends obliquely inside the mesentery up to the root of right iliac fossa. It is accompanied by superior mesenteric vein to its right side and is surrounded by a plexus of autonomic nerves. The SMA gives branches to jejunum, ileum and right colic, inferior pancreaticoduodenal (IPD), ileocolic, and middle colic artery. Variations in the course and branching pattern of SMA are of significant importance in gastrointestinal surgeries. Methodology: A prospective study was conducted with the convenient sample size of thirty cadavers. After opening the anterior abdominal wall, peritoneum and viscera were carefully separated and cleaned. The abdominal aorta with its branches was identified. SMA was identified at its origin. The course of the artery and its branches were traced and noted. The findings were tabulated and analyzed. The relation of superior mesenteric vein with the artery was identified and noted. Results: Variations in the branches of SMA were observed in 14 cadavers. We observed the absence of middle colic artery in four cadavers. Higher origin of ileocolic artery was found in two cadavers. One common trunk divides into middle colic artery and accessory right colic artery and another common trunk divides into right colic artery and ileocolic artery in a cadaver. The right colic artery and middle colic artery were found to take origin from a common trunk in a cadaver. The common trunk for IPD (artery and middle colic artery was found in one cadaver. The common trunk for right colic artery and ileocolic artery was observed in four cadavers. Accessory right colic artery was observed in four cadavers. The common trunk for accessory right colic artery and middle colic artery was found in two cadavers. Accessory right colic artery, right colic artery, ileocolic artery, and ileal branches had their origins from a common trunk in a cadaver. Variations in relation between SMA and superior mesenteric vein were found in two cadavers. Conclusion: Awareness and knowledge regarding the variations in SMA and its relation with vein are important for surgeons and radiologists to avoid both intraoperative and postoperative complications during surgical and diagnostic procedures involving intestines.