ShapeThe liver is pyramidal in shape with its base at the left and its apex toward the right. The external surface of the liver is smooth with the apex rounded over, similar to a large mushroom cap. (see diagram below) Normal liver – falciform ligament Image courtesy of LifeArt Lippincott, Williams & Wilkins All rights reserved The pyramidal and mushroom shape of the liver is exemplified by this drawing. The falciform ligament runs an oblique course between the medial and lateral segments of the liver. At its inferior edge is a rounded ligament called the ligamentum teres. It is the remnant of the umbilical vein that brought maternal and placental blood to the developing fetus and baby.In cross sectional imaging, the surface of the liver is interrupted by normal notches and grooves. The most obvious are the grooves and fissures within the porta hepatis and the region of the entry point of the falciform ligament.NotchesThe anterior smooth surface of the liver is interrupted by the notch caused by the entrance of the falciform ligament. Opposite this notch is a corresponding “internal” notch. These notches separate the medial (IV) and lateral (II & III) segments of the left lobe. Other internal notches are the interlobar groove which separates the right and left lobes, (IV & V) and the notch which reflects the position of the right hepatic vein. This notch indicates the line of division between the anterior and posterior segments of the right lobe.(in this case V & VI) (Image courtesy of Ashley Davidoff M.D.)In the following image, the thick blue line runs to the interlobar fissure and corresponds to the border between the right and left lobes as well as the expected location of the middle hepatic vein and gallbladder axis. The thin blue line runs between the border of the anterior and posterior segments of the right lobe and corresponds to the expected location of the right hepatic vein.Obliterated umbilical veinOf special note: The yellow dot in the falciform ligament represents the obliterated umbilical vein which is a remnant of the embryologic left umbilical vein which transported blood from the mother to the developing fetus. The thick blue vein runs to the interlobar fissure and corresponds to the border between the right and left lobes, as well as the expected location of the middle hepatic vein and gallbladder axis. The thin blue line runs between the border of the anterior and posterior segments of the right lobe and corresponds to the expected location of the right hepatic vein. (Image courtesy of Ashley Davidoff M.D.)We reviewed the following image when we discussed the malleability of the liver, indicating that the tendons of the diaphragm were able to indent the soft liver.Lobulated liverIn this instance we se the example to show a variation of the normal smooth, and mushroom shaped surface. This lobular contour is a normal variant. (Image courtesy of Ashley Davidoff M.D.)Compare the previous normal variant with the abnormal lobular contour of this liver. There is a distinct lack of uniformity with coarse micronodular and macronodular change. This is an example of severe cirrhosis.Lobulated liverThis liver has suffered the consequences of cirrhosis, in which the liver tissue is replaced by scar tissue resulting in an overall shrinkage of the liver. (Image courtesy of Ashley Davidoff M.D.)This image shows only micronodular change at the surface of the liver. Congenital Fetal Lobultion13446 liver hepatic applied biology shape lobulation anatomy Davidoff MDHepar Lobatum13454 liver applied biology shape anatomy hepar lobatum congenital syphilis infection fibrosis Davidoff MD Courtesy Barbara Banner MDLobulated liverThis image highlights the abnormal area. Compare this image to the previous normal images to review the normal vs. abnormal contour of the liver. (Image courtesy of Ashley Davidoff M.D.) The highlighted area in the image below reveals micronodular cirrhosis, a characteristic of alcoholic cirrhosis.Lobulated liverThis image highlights the abnormal area. Compare this image to the previous normal images to review the normal vs. abnormal contour of the liver. (Image courtesy of Ashley Davidoff M.D.)Position
