Connective tissue configuration in the human liver hilar region with special reference to the liver capsule and vascular sheath

Background/Purpose: We carried out this study to examine the validity of the accepted dogma that: (1) the human liver capsule does not extend along the fissures for the hepatic veins; (2) the hilar vasculobiliary sheath does not connect to the liver capsule; and (3) the hilar plate is a thickening of the vasculobiliary sheath. Methods: Using cadaveric specimens, we identified composite fibers and other structures in the sheath and capsule histologically. Results: The liver capsule, Glisson's sheath, and the sheath for the hepatic vein tributaries were characterized by a high content of thin, wavy elastic fibers. However, the hilar vasculobiliary sheath of the thick vessels and ducts did not contain elastic fibers. Along the roof of the hilar region, vaginal ductuli were identified as a chain of cross-sectional bile ducts with a relatively thick wall, because of their tortuous course with abundant small pouches budding from the surface. The ductuli were separated from the liver capsule by abundant lymphatic vessels. Conclusions: The sheath for hepatic veins and Glisson's sheath appear to connect to, and be continuous with, the liver capsule. During surgery and dissection, it should be borne in mind that the hilar plate is likely to be artificially developed when, without intention, surgeon bundle collagenous fibers with vaginal ductuli forming a core.