Evaluation of Numerical and Positional Variations of the Hepatic Veins: A Cadaveric Study.

Introduction: Hepatic veins are the major linking vessels between systemic and portal circulation. Numerical and positional variation of the hepatic veins can play a significant role during surgical interventions on the liver. Materials and Methods: Gross anatomical study regarding the number and arrangement pattern of hepatic veins was undertaken on 88 adult livers which were stored in 10% formalin after the regular dissection classes. Result: Six livers (7%) were found to be drained only by major hepatic veins, whereas 82 out of 88 livers (93%) had accessory (minor) hepatic veins. The total number of persistent hepatic veins ranged from 2 to 10 with the highest prevalence of four hepatic veins (35.2%) followed by 5 (19.3%) and 6 (17%). The presence of three major veins was seen in 45 (51%) livers while 41 (47%) livers had two major hepatic veins. Remaining two livers (2%) showed the presence of four major hepatic veins. In 95% specimens, the minor hepatic veins entered the inferior vena cava below the level of entry of major veins. In 2.5% cases, their entry point was above the major veins and in 2.5% cases, the entry point was below major veins. Conclusion: The data resulting from this study provides a clear idea about the number and drainage pattern of the hepatic veins into the liver. Knowledge of numerical and positional variations of hepatic veins could be useful in normal Doppler ultrasound hepatic vein flow velocities and their variation with respiration in healthy adults as comparable with the similar approach of superior vena cava.