1192 THE DIGESTIVE SYSTEM. 



(1) The Lobus Quadratus. This is a quadrilateral area upon the inferior surface, 

 extending from the margo anterior in front to the porta hepatis behind. On the 

 right, it extends as far as the fossa for the gall-bladder, and on the left to the fossa 

 for the umbilical vein. The surface is flattened or concave, and is mainly in con- 

 tact with the pyloric part of the stomach and the duodenum. 



(2) The Lobus Caudatus [Spigeli] (O.T. Spigelian Lobe). This is a prominent 

 rather quadrilateral area on the posterior surface of the liver, between the fossa for 

 the inferior vena cava on its right, and the fossa for the ductus venosus on its 

 left side. 



Its superior limit is formed by the terminal part of the ductus venosus, as it 

 bends to the right to join the vena cava inferior, while, inferioiiy, it is free and forms 

 the posterior boundary of the porta hepatis. 



This extremity is often cut into by a notch or fissure (in which the coeliac 

 artery lies, particularly in the foetus), which marks off a larger and more prominent 

 left part, the processus papillaris, projecting downwards behind the porta hepatis, 

 and a smaller right part, the processus caudatus, which connects it (Fig. 938) with 

 the inferior surface of the right lobe. 



The posterior surface of the caudate lobe is free ; it is placed vertically, and 

 looks backwards and slightly to the left. The lobe has also another surface, which 

 is hidden when in the body and in the hardened liver by the folding of the left 

 lobe across it. By this folding there is formed a deep fossa (fossa for the ductus 

 venosus), at the bottom of which will be found the remains of the ductus venosus. 



(3) The processus caudatus (O.T. caudate lobe) is merely a narrow bridge of 

 liver tissue which connects the caudate lobe with the right lobe proper. It is 

 limited anteriorly by the porta hepatis, arid posteriorly by the fossa for the inferior 

 vena cava. It forms the superior boundary for the epiploic foramen, and when the 

 finger is placed in the foramen it rests against the caudate process, and has a vein 

 on each side, i.e., in front and behind, separated by a layer of peritoneum. 



Facies Posterior (Posterior Surface). This portion of the parietal surface is 

 directed backwards, and lies in contact with the diaphragm, as the latter passes 

 down on the posterior abdominal wall. It is very irregular in shape, and presents 

 the following parts : (1) The " uncovered area " of the right lobe ; (2) the supra- 

 renal impression ; (3) the fossa for the vena cava ; (4) the caudate lobe, separated 

 by the fossa for the ductus venosus from (5) the oesophageal groove, which belongs 

 to the left lobe. 



(1) The " uncovered area " of the right lobe (Fig. 938) is a considerable portion 

 of the posterior surface of the right lobe varying from 1J to 3 inches (3'7 to 

 7'5 cm.) in width, and from 3 to 5 inches (7'5 to 12*5 cm.) in transverse measure- 

 ment which is devoid of peritoneum. Over this uncovered portion, which looks 

 more medially than backwards, the liver and diaphragm are in direct contact, and 

 are united by areolar tissue ; here too is established a communication by small 

 veins between the portal circulation of the liver and the systemic circulation of the 

 diaphragm. 



(2) Impressio Suprarenalis. On the " uncovered area," immediately fco the right 

 of the vena cava, is a triangular impression (Fig. 938), produced by a portion of 

 the right suprarenal gland, which projects upwards from the superior extremity of 

 the right kidney, between the diaphragm and liver. 



(3) Fossa Venae Cavse. At the left extremity of the " uncovered area " the 

 inferior vena cava lies vertically, embedded in a fossa of the liver substance, 

 between the caudate lobe on the left and the adjacent part of the uncovered 

 area on the right, both of which project over the sides of the vein, almost hiding 

 it from view (Fig. 938) ; sometimes they actually meet and form a pons hepatis 

 across the back of the vein. 



(4) Lobus Caudatus [Spigeli]. This has already been described see above. The 

 superior recess of the omental bursa separates the posterior surface of the caudate 

 lobe from the diaphragm, which latter, in turn, separates it from the -thoracic 

 part of the descending aorta just before that vessel enters the abdomen. 



(5) The Impressio CEsophagea, or oesophageal groove, is situated on the posterior 

 surface of the left lobe, to the left of the superior end of the caudate lobe, but 



