INTRODUCTION
The coeliac trunk (CT) is the most cephalic unpaired ventral branch of abdominal aorta. It commonly divides into left gastric, common hepatic (CHA) and splenic arteries. The superior mesenteric artery (SMA) is the second ventral branch of abdominal aorta. The branches of SMA are inferior pancreaticoduodenal, jejunal, ileal, ileocolic, right colic and middle colic arteries. The middle colic artery (MCA) descends in the transverse mesocolon and divides into right & left branches (Standring 2005). These branches form part of marginal artery and supply mostly transverse colon.
Variations in the branching pattern of ventral branches of abdominal aorta are not infrequent. There have been reports of anomalies of coeliac trunk in the past. The common hepatic artery originates from coeliac trunk in 51-80% cases (Adachi 1928; Chen et al. 1998). Several other branches such as inferior phrenic arteries, dorsal pancreatic artery and middle colic artery may also arise from the coeliac trunk (Chitra 2010). Aberrant origin of middle colic artery have been reported earlier (Yildrim et al. 2004). Adachi (1928) observed origin of middle colic artery from the coeliac trunk in 0.5% to 1% cases. Middle colic artery originating from the proximal segment of splenic artery as observed in the present case is a rare anomaly. A precise knowledge of such arterial variations are important for diagnostic procedures and surgeries of upper abdomen.

CASE REPORT
During routine dissection of abdominal retroperitoneal region for first year medical students, a variant branching pattern of ventral branches of abdominal aorta was detected in a 50-year-old male cadaver. The specimen was photographed after delineating the surrounding structures.
The coeliac trunk originated from the ventral aspect of abdominal aorta and bifurcated into left gastric and splenic arteries. The common hepatic artery arose directly from the abdominal aorta 0.2 cm inferior to the origin of celiac trunk. Nothing abnormal was observed in the further course and branching pattern of common hepatic artery.
The middle colic artery, normally a branch of superior mesenteric artery originated from the proximal segment of the splenic artery (Figure 1). The artery then passed posterior to the body of pancreas to enter into transverse mesocolon (Figure 2). Two cms proximal to the transverse colon, it divided in to right and left branches. These branches anastomosed with the ascending branch of iliocolic and left colic arteries respectively to form the marginal artery. The length of the middle colic artery was 12 cm and had a diameter of 0.8 cm, near its origin. It gradually narrowed towards its termination. No separate middle colic artery originating from superior mesenteric artery was seen. Other branches of superior mesenteric artery i.e. right colic, ileocolic, ileal and jejunal branches were normal. The distance between the coeliac trunk and the superior mesenteric artery was 1 cm.

DISCUSSION
Variations of hepatic artery are important in liver transplantation. There have been reports of right hepatic artery originating from the middle colic artery, directly from the aorta and a left hepatic artery originating from the common hepatic artery (Ugurel et al. 2010). The origin of hepatic artery are of six types according to Hiatt’+s clasiification. The origin of CHA directly from the aorta belongs to type VI (Hiatt et al. 1994). The present case also observed the type VI origin of CHA.
The superior mesenteric artery or one of its major branches give origin to middle colic artery. It may arise from the (a) coeliac trunk (Standring 2005), (b) abdominal aorta between the origin of superior and inferior mesenteric artery (Benton & Cotter 1963), (c) inferior mesenteric artery (Benton & Cotter 1963; Chen et al. 1998) , (d) common hepatic artery (Cavdar et al. 1998). It may be absent in 3 to 5% of cases (Hiatt et al. 1994). However, the origin of middle colic artery from the proximal segment of splenic artery is a rare anomaly and to the best of our knowledge only one case has been reported in the past (Chou et al. 1997). The unusual origin, variable course and a smaller lumen of the anomalous middle colic artery increases the risk of vascular damage to ascending and transverse colon.
The variations of the coeliac trunk can be due to abnormal embryological development of the ventral splanchnic arteries. The anomalous middle colic artery originating from splenic artery can be due to the persistence of longitudinal anastomosis between the vitelline arteries in the embryo (Cavdar et al. 1998).
The origin of common hepatic artery directly from abdominal aorta and middle colic artery from the splenic artery is a rare finding and such a possibility should be kept in mind to ensure a safe and successful abdominal surgery.

CONCLUSION
Awareness of anatomical variations in the origin and branching pattern of arteries arising from the coeliac trunk and superior mesenteric trunk are necessary for surgeons and radiologist to avoid vascular complications.