434 SPLANCHNOLOGY, OR ANATOMY OF THE VISCERA 



The descending colon descends from the splenic flexure, to 

 end at the left iliac fossa in the sigmoid flexure. It is covered 

 in front and laterally by the peritoneum. It occupies the 

 left hypochondriac and lumbar regions. 



The Relations of the Cecum. It lies in the right iliac fossa, 

 resting on the ileopsoas muscle, immediately behind the abdom- 

 inal wall. The appendix, the first lumbar nerve, the geni to- 

 crural, and external cutaneous branches of the lumbar plexus 

 are in relation with it behind. Internal at the brim of the 

 pelvis are the external iliac vessels and the ureter, as it crosses 

 the bifurcation of the common iliac. 



The arteries of the cecum are: The anterior and posterior 

 cecal arteries, branches of the iliocolic. They are given off 

 at the ileocecal junction. The veins are the same as the arteries 

 and open into the superior mesenteric vein through the ileo- 

 colic. They are radicles of the portal system. The nerves 

 are derived from the sympathetic system, through the superior 

 mesenteric plexus. The lymphatics drain into the superior 

 mesenteric nodes through the channels of the ileocecal nodes. 



The Relations of the Ascending Colon. In front, the coils of 

 the ileum and abdominal wall; behind, the quadratus iumborum 

 muscle, the lower thoracic intercostal nerves, the anterior 

 and lower surface of the right kidney; above, the hepatic 

 flexure of the colon rests against the inferior surface of the 

 right lobe of the liver in the impressiocolica and the gall-bladder. 

 Internally, the second portion of the duodenum touches the 

 hepatic flexure. 



The Relations of the Transverse Colon. It describes an arch 

 with its concavity directed backward and upward to the verte- 

 bral column. Above, it is in touch with the liver and gall- 

 bladder, the greater curvature of the stomach, the lower end 

 of the spleen; below with the small intestines; by its anterior 

 surface with the layers of the great omentum and the abdominal 

 wall; posteriorly it rests, the right side, on the second portion 

 of the duodenum and head of the pancreas, and on the left 

 side is in relation with coils of the jejunum and ileum. 



The splenic flexure is in relation with the posteroinf erior surface 

 of the stomach, the tail of the pancreas, and the diaphragm 

 opposite the tenth and eleventh ribs. The phrenocolic liga- 

 ment attaches it to the diaphragm. 



