THE ABDOMEN 711 



An omentum is a double fold of peritoneum passing between two 

 abdominal viscera. The omenta are three in number, namely, the 

 great or gastro-colic omentum (epiploon), which passes between the 

 great curvature of the stomach and the transverse colon, the small 

 or gastro- hepatic omentum, which passes between the small curva- 

 ture of the stomach and the portal fissure of the liver, and the 

 gastro-splenic omentum, which passes between the posterior sur- 

 face of the cardiac end of the stomach and the gastric surface of 

 the spleen. 



A mesentery is a double fold of peritoneum passing between a 

 portion of intestine and the abdominal wall. The mesenteries in 

 the adult are normally as follows : the mesentery proper, which 

 connects the jejunum and ileum to the vertebral column ; the 

 appendicular mesentery or meso- appendix, which is connected 

 with the vermiform appendix ; the transverse meso-colon, which 

 extends between the transverse colon and the posterior wall of the 

 abdomen at the anterior border of the pancreas ; and the pelvic 

 meso-colon, which connects the pelvic colon to the anterior surface 

 of the sacrum as low as the third sacral vertebra. Occasionallj' 

 the ascending colon, descending colon, and iliac colon are each 

 provided with a mesentery, called respectively the ascending 

 meso-colon, descending meso-colon, and iliac meso-colon. 



A ligament is a fold of peritoneum which connects a viscus net 

 intestine to the abdominal or pelvic parietes. The peritoneal liga- 

 ments are as follows : (i) the ligaments of the liver, namely, the 

 falciform ligament, the coronary ligament, and the right and the 

 left lateral or triangular ligaments ; (2) the gastro-phrenic ligament ; 

 (3) the lieno-phrenic ligament ; (4) the false ligaments of the 

 urinary bladder, namely, two posterior, two lateral, and superior ; 

 and (5) the broad ligaments of the uterus. 



Course of the Peritoneum. — ^The parietal and visceral layers of 

 the peritoneum are in unbroken continuity with each other, and 

 this continuity is shown by tracing the membrane in the vertical 

 and transverse directions. 



Vertical Course. — Commencing at the portal fissure of the liver 

 two layers of peritoneum descend to the small curvature of the 

 stomach, forming the gastro-hepatic omentum. On reaching the 

 small curvature these two layers separate, one passing over the 

 anterior surface, and the other over the posterior surface, of the 

 stomach. At the great curvature they come together, and 

 descend in the form of a curtain over the coUs of the jejunum and 

 ileum to the lower part of the abdomen, forming the two anterior 

 or descending layers of the gastro-colic omentum. These two layers 

 are then folded backwards and ascend to the transverse colon, 

 thus forming the two posterior or ascending layers of the gastro- 

 colic omentum. On reaching the transverse colon they separate, 

 one layer passing in front of, and above, the bowel, and the other 

 layer below and behind it. Having enclosed the transverse colon, 

 the two layers meet, and are prolonged backwards to the posterior 



