The liver is wedge-shaped and has three surfaces. These are superior, inferior, and posterior. The posterior forms the base of the wedge and its anterior edge is the apex. The liver is divided into five lobes by five primary fissures and has • five ligaments (Fig. 428).

The lobes of the liver are: (1) left, (2) right, (3) quadrate, (4) Spigelian, (5) caudate. The left lobe is one-sixth the size of the right. It comprises that part to the left of the falciform ligament above and the umbilical and ductus venosus fissures below. The right lobe comprises that part to the right of the falciform ligament above and the fissures of the gall-bladder and vena cava below. The quadrate lobe is the anterior, small, square-shaped lobe between the fissure of the gall-bladder on the right and the umbilical fissure on the left. It extends from the anterior edge back to the portal fissure. The Spigelian lobe is best seen posteriorly, extending from the vena cava on the right to the fissure of the ductus venosus on the left. The caudate lobe or process is the name given to the liver tissue running from the lower end of the Spigelian lobe to the right lobe. It passes behind the portal fissure and between it and the vena cava. Riedel's lobe is the name given to an abnormal, tongue-like projection of liver tissue from its anterior edge, which may extend downward either over the gall-bladder or external to it. Mayo Robson has seen it extend to the caecal 27 region, and an inflamed gall-bladder being directly beneath caused pain to be experienced at McBurney's point. This condition is liable to be mistaken for appendicitis. The fissures of the liver are best understood by examining its under surface, where they can be seen arranged in the form of the letter H. They are as follows: (1) The umbilical fissure, running from the umbilical notch on the anterior edge to the left end of the portal (transverse) fissure; it contains the round ligament. (2) The fissure of the ductus venosus, running upward from the left end of the portal fissure between the left and Spigelian lobes; it contains the remains of the fetal ductus venosus.

Fig. 428.   View of the anterior and upper surfaces of the liver.

Fig. 428. - View of the anterior and upper surfaces of the liver.

(3) The fissure of the gall-bladder, separating the quadrate from the right lobe and ending at the right extremity of the portal fissure; in it lies the gall-bladder. (4) The fissure of the vena cava, between the Spigelian and right lobes, lodging the vena cava. (5) The portal fissure; - this forms the transverse bar of the H. Its left end receives the umbilical and ductus venosus fissures and its right end the fissures of the gall-bladder and vena cava. It contains the portal vein, hepatic artery, hepatic duct, nerves, and lymphatics; attached to its sides is the lesser or gastrohepatic omentum. The portal fissure is also called the transverse fissure, and the name longitudinal fissure is sometimes applied to the combined umbilical and ductus venosus fissures. (In the recent anatomical nomenclature these fissures are called fossae.) (Fig. 429.) The ligaments of the liver are five in number: (1) the coronary, (2) the triangular, (3) the falciform, (4) the round, and (5) the ligament of the ductus venosus. The coronary ligament surrounds the posterior surface which is not covered by peritoneum. It is 4 to 6 cm. (1 1/2 to 2 1/2 in.) wide and extends from the vena cava 7.5 to 10 cm. (3 to 4 in.) to the right, terminating in a pointed end which has been called the right lateral ligament. The triaingular ligament, also called the left lateral, extends as far to the left of the falciform ligament as the coronary-does to the right. It is attached to the diaphragm in front of the oesophagus, while the coronary is attached to the back of the diaphragm. The falciform ligament starts near the umbilicus, passes to the umbilical notch of the liver 2.5 to 4 cm. (1 to 1 1/2 in.) to the right of the median line and thence over the top of the liver to near its posterior edge, where it blends in front of the vena cava on the right side with the coronary ligament and on the left with the triangular ligament. The round ligament is the round cord in the free edge of the falciform ligament which runs from the umbilicus to the umbilical notch and thence to the portal fissure to join the left branch of the portal vein. It is the remains of the fetal umbilical vein. The ligament of the ductus venosus runs from the left branch of the portal vein to the-vena cava in the fissure of the ductus venosus. The ductus venosus, like the umbilical vein, becomes obliterated at birth.

Fig. 429.   View of the posterior and inferior surfaces of the liver.

Fig. 429. - View of the posterior and inferior surfaces of the liver.

Position of the .Liver. - The liver rises to the fourth costal interspace on the right side, to or slightly above the xiphosternal junction in the midline, and the lower border of the fifth rib on the left side, to its extremity, just beyond the apex of the heart, at the lower border of the sixth rib. Its lower border passes from this point to the eighth left cartilage, crosses the middle line about midway between the xiphoid articulation and umbilicus to the ninth right costal cartilage, and thence follows the edge of the ribs posteriorly, being about 2.5 cm. (1 in.) lower in women. The upper limits of its percussion dulness are the upper border of the sixth rib in the right mammillary line, the eighth in the axillary, and the tenth in the scapular.

Fig. 430.   The bed of the liver. The liver has been removed to show the surrounding structures.

Fig. 430. - The bed of the liver. The liver has been removed to show the surrounding structures.