1258 



THE ORGANS OF DIGESTION 



2. In the Lower Abdomen (Fig. 981). Starting from the linea alba, below the 

 level of the transverse colon, and tracing the continuity in a horizontal direction 

 to the right, the peritoneum covers the inner surface of the abdominal wall almost 

 as far as the outer border of the Quadratus lumborum; it encloses the cecum and 

 appendix, and is reflected over the sides and anteribr surface of the ascending 

 colon; it may then be traced over the Psoas muscle and the inferior vena cava 

 toward the middle line, whence it passes along the mesenteric vessels to invest 

 the small intestine, and back again to the large vessels in front of the vertebral 

 column, forming the mesentery, between the layers of which are contained the 

 mesenteric bloodvessels, nerves, lacteals, and lymph nodes. It is then continued 

 over the left Psoas muscle; it covers the sides and anterior surface of the descending 

 colon, and, reaching the abdominal wall, is continued on it to the middle line. 



3. In the Upper Abdomen (Fig. 982). Above the transverse colon the peri- 

 toneum can be traced, forming the greater and lesser sacs, and their communication 

 through the foramen of Winslow can be demonstrated. 



Small Lymphatic Inferior Ascending 

 intestine node vena cava colon 

 \ 



Periton 



Mesocolon 

 (imperfect) 



Descending 

 colon 



Right 

 kidney 



Left kidney 



FIG. 981. Peritoneal reflection in transverse section of lumbar region below the transverse colon. Seen 

 from above. Schematic. (Tillaux.) 



(a) Greater Sac. Commencing on the posterior abdominal wall at the inferior 

 vena cava, the membrane may be followed to the right over the front of the upper 

 part of the right kidney on to the antero-lateral abdominal wall. From the middle 

 of the anterior wall a backwardly directed fold encircles the impervious umbilical 

 vein and forms the falciform ligament of the liver. Continuing to the left, the 

 peritoneum lines the lateral abdominal wall and covers the outer part of the front 

 of the left kidney, and is reflected to the posterior border of the hilus of the spleen 

 as the posterior layer of the lienorenal ligament (Fig. 985). It can then be traced 

 over the surface of the spleen to the front of the hilus, and thence to the cardiac 

 extremity of the stomach as the anterior layer of the gastrosplenic omentum. It 

 covers the antero-superior surface of the stomach and first part of the duodenum 

 and extends up from the lesser curvature of the stomach to the liver, the latter 

 portion forming the anterior layer of the gastrohepatic omentum. 



(b) Lesser Sac. On the posterior abdominal wall the peritoneum of the greater 

 sac is continuous with that of the lesser sac in front of the inferior vena cava. 



