| Objective:To provide more accurate anatomical facts and figures of intrahepatic vessels and hepatic segment for developing hepatic surgery, fixed liver dissecting specimens and helical CT three-dimensional reconstructing images of portal vein and hepatic vein were used in this study to reinvestigate portal venous system.Methods:The vessels carving technique was used on right anterior segment of 25 fixed liver specimens. The helical CT three-dimensional reconstruction technique was used on 15 donated human fresh isolates liver specimens and 15 patients with normal liver. The courses, distributions, quantities, and ramifications of the third-order of portal branches were analyzed. The further division of right anterior segment was defined. The anatomical landmark of intersubsegmental plane was searched. The position of the intersubsegmental plane in the surface of liver was defined.Results:1 The courses, distributions, quantities, and ramifications of the third-order of portal branches of right anterior segmentThe third-order of portal branches of right anterior segment went up, down, left, right, and anterior. There was a lacking vessels oblique fissure among the third-order of portal branches of right anterior segment. This oblique fissure was observed in 53 livers of 55. The third-order of portal branches were divided into 2 distinct groups by the oblique fissure. One group was located in the left anterior of the oblique fissure, and portal branches in this group nourished the ventral region of right anterior segment. The other group was located in the right posterior of the oblique fissure, and portal branches in this group nourished the dorsal region of right anterior segment. Besides the 53 livers, the third-order of portal branches of a fixed liver specimen and a fresh isolated liver specimen went up and down, and nourished the upper region of right anterior segment and the lower region of right anterior segment. There were not lacking vessels oblique fissures among the third-order of portal branches of right anterior segment in these two liver specimens.The third-order of portal branches of right anterior segment in 24 fixed liver specimens and 14 fresh isolated liver specimens were observed. The quantities of the third-order of portal branches of right anterior segment in these liver specimens were 2-13. The quantities of the third-order of portal branches in ventral region were 1-7. The quantities of the third-order of portal branches in dorsal region were 1-7.Analysis of the portal branches revealed 5 distinct anatomical variants of the third-order of portal branches of right anterior segment. Type a accounted for 80%. The third-order of portal branches in this type went up, down, left, right and anterior, nourished the ventral region and the dorsal region, respectively. Type b accounted for 7.5%. The third-order of portal branches in this type come from right anterior branch of portal vein, nourished the ventral region and the dorsal region, respectively. Type c accounted for 5%. The third-order of portal branches in this type come from right branch of portal vein, nourished the ventral region and the dorsal region, respectively. Type d accounted for 2.5%. A third-order of portal branch in this type comes from right posteroinferior of portal vein, nourished the ventral region. A third-order of portal branch in this type comes from left branch of portal vein, nourished the dorsal region. Type e accounted for 5%. The third-order of portal branches in this type went up and down, nourished the upper region and the lower region, respectively. 2 The hepatic vein coursed in the lacking vessels oblique fissure and the position of the lacking vessels oblique fissure on the inferior border of liverThere was a lacking vessels oblique fissure among the third-order of portal branches of right anterior segment. The third-order of portal branches of right anterior segment were divided into two groups by the lacking vessels oblique fissure. They were respectively ventral branches group and dorsal branches group. A hepatic vein coursed in the oblique fissure. The hepatic vein might be the first-order tributary of MHV (39/53), the first-order tributary of RHV (7/53), the second-order tributary of MHV (2/53), the second-order tributary of RHV (2/53), and the accessory of MHV (3/53).24 fixed liver specimens were observed, we found that the distance between the intersubsegmental plane and the midpoint of fossa for gallbladder was (63.72±20.50)mm, the distance between the right border of liver and the midpoint of fossa for gallbladder was (117.58±22.73)mm. The ratio of these two distance was (0.53±0.10).Conclusion:1 There was a lacking vessels oblique fissure among the third-order of portal branches of right anterior segment. The right anterior segment could be redivided into ventral subsegment and dorsal subsegment by the oblique fissure.2 A hepatic vein coursed in the intersubsegmental plane between ventral subsegment and dorsal subsegment. It could serve as an anatomical landmark of the intersubsegmental plane.3 The intersubsegmental plane on the surface of liver could be defined as the line draw from the hepatic vein straight through the midpoint of fossa for gallbladder and the right border of liver. Objective:The aim of this study is to search for a new specimen preparing method, which could demonstrate intrahepatic vessels and the relationships between internal vessels and external structures of liver simultaneously. This method could be a foundation for defining more accurate relationship between intersubsegmental plane of right anterior segment and external structures of liver.Methods:Rabbit livers were prepared with three different techniques in this study:(a)corrosion-cast technique; (b)transparency technique; and (c)combination technique of cast and transparency.Results:The corrosion cast specimens in Group A could show the ramifications of portal branches, the quantities, courses of portal branches, the major HV and the first-order tributary of HV. The transparent specimens in Group B could demonstrate that the shape, ligaments, fossa and fissures of liver were kept. The combination of casting and transparent specimens in Group C could display both the internal hepatic vessels and the preserved external structures of liver. And the location relationships between the internal vessels and external anatomical structures could also be clearly seen.Conclusion:Improved combination technique of cast and transparency was an effective method which could display the location relationships between the internal vessels and external anatomical structures.
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