This inclusion of the vena cava in the fissure or fossa of that name on the dorsal surface of the liver affords, so to speak, the vertical measure of the non-peritoneal area of the liver attached directly to the diaphragm. As the vein develops the interval between the two layers of the right coronary ligament increases, producing the well-known large non-peritoneal area on the dorsal surface of the adult liver, which is directly attached to the diaphragm. Immediately to the left of the vena cava, however, the original condition persists. The area of direct diaphragmatic attachment is narrow and consequently the two layers of the coronary ligament are close together at this point.[7] [7] It should be remembered that in the final adult arrangement of the abdominal viscera the liver shifts relatively backwards, so that the diaphragmatic attachment, originally directed cephalad, now looks dorsad and forms part of the dorsal or "posterior" surface of the adult organ. The original ventral surface looks cephalad, as well as ventrad, forming the convex surface which in the adult rests in contact with the abdominal wall and diaphragmatic vault, while the surface originally directed dorsad toward the stomach finally in large part has an inclination caudad forming the "inferior" surface of human anatomy. In this way a species of recess (Spigelian recess or hepatic antrum of lesser sac) is formed. A portion of the dorsal liver surface lying just to the left of the vena cava, between it and the ductus venosus, remains invested by peritoneum which is reflected from the boundaries of this space to the diaphragm. This forms the Spigelian lobe (Fig. 278). The lobe is bounded to the right by the postcava, to the left by the reflection of the lesser omentum to the stomach along the fissure for the ductus venosus; cephalad the boundary is formed by the reflection of the caudal layer of the coronary ligament to the diaphragm. The caudal boundary is afforded by the transverse position which the lesser omentum has assumed in the region of the transverse or portal fissure. It will be seen that the original continuity of the Spigelian lobe with the caudal surface of the right lobe is maintained by the narrow bridge of liver tissue connecting the caudal right angle of the rectangular Spigelian lobe with the right lobe. This narrow isthmus, situated between vena cava dorsad and the free right edge of lesser omentum ventrad, forms the so-called _caudate lobe_. [Illustration: FIG. 279.--Liver of human foetus at eighth month. View of caudal and dorsal surfaces. (Columbia University Museum, No. 1854.)]