Objective:To provide anatomic basis for the location and protection of the tributaries of the inferior vena cava (IVC) in the retroperitoneal surgery.Methods:Fifty adult cadavers fixed with formalin were collected at random for study.The IVC and its tributaries were dissected

observed and measured in the region from the confluence of the left and right common iliac vein to the superior border of left renal vein(the initiative segment of IVC).Results:(1)The length of this segment of IVC was 13.12+1.51cm

and outer-diameter was 2.25±0.24cm.The number of vein tributaries from this segment was 8.75±2.02

66.3% of the tributaries entered the IVC posteriorly

and 66.4% of the tributaries entered the IVC on renal region(renal segment of IVC i.e.segment from the inferior end of right kidney to the superior border of left renal vein).(2)Vein tributaries:①Right gonad vein:84.9% of these veins entered the IVC anteriorly.The average distance from the point where the right gonad vein entering the anterior wall of IVC was approximately 3.56±0.85cm away from the superior border of left renal vein.②Lumbar vein(100%):The location of the lumbar veins in the infrarenal portion of the IVC was highly variable.A great number of veins was noted on the left(3～4)than on the right side(2～3). The veins tended to enter the IVC at different levels and not in pairs.③Surgical vein of mesentery(86%):The average distance from the point where the surgical vein entered the left side of anterior wall of IVC to the superior border of left renal vein was approximatately 6.94±1.21cm.④Right suprarenal vein(20%).⑤Right assistant renal vein (25%)⑥Right vein around kidney (36%).⑦Right inferior phrenic vein (6%).Conclusion:The result provides further morphological basis for retroperitoneal surgery.