The portal bifurcation and the termination of the hepatic veins: an anatomical investigation into the projection of the ultrasonographically important hepatic vessels onto the anterior body wall.

An investigation was carried out on 50 cadavers, in which the projection onto the anterior abdominal wall of the following vascular points was examined: the portal bifurcation, the direction of the course of the right and left branches of the portal vein and the terminal course of the hepatic veins near their entry into the inferior vena cava (IVC). The results are related to a transverse axis passing through the apex of the xiphoid process and the median plane in the supine position. The average position of the portal bifurcation is projected onto a point between a vertical line passing through the midpoint of the right hemithoracic width and a horizontal line passing through a point on the midclavicular line (MCL) corresponding to 57% of the height of the liver measured upwards from its inferior margin. The axis of the prehepatic course of the portal vein makes an angle of about 50 degrees, open downwards, with a vertical line drawn through the apex of the internal angle of the portal bifurcation. A line parallel to the course of the right and left branches of the portal vein is projected on to a surface line cranial to the right costochondral margin, which runs upwards at an angle of approximately 20 degrees towards the apex of the xiphoid process. The termination of the three great hepatic veins is projected at about the level of the xiphisternal joint, one sternal width to the right of the midline. Close to the IVC, the right hepatic vein runs upwards and medially at an angle of between 20 degrees and 30 degrees with the transverse plane.(ABSTRACT TRUNCATED AT 250 WORDS)