484 A MANUAL OF ANATOMY. 



Summary of the Development of the Viscera and Peri- 

 toneum. 



(1) The alimentary canal is first undifferentiated and a 

 straight tube. 



(2) It is attached to the backbone by a thin membrane 

 the primitive peritoneum. Also for its upper portion to 

 the anterior abdominal wall. Diag. 32. 



(3) As development proceeds the various parts of the 

 alimentary canal appear, as stomach, duodenum, small in- 

 testine, large intestine (colon, omega loop, rectum). 



(4) The peritoneum attached to these various parts of the 

 intestinal canal receives special names according to the part 

 to which it is attached, as mesogaster, mesoduodenum, 

 mesentery, mesocolon, sigmoid mesentery, mesorectum. 



(5) As the alimentary canal grows it becomes thrown into 

 loops, the greatest lengthening taking place in the part 

 known as the small intestine. Diag. 33. 



(6) The primitive relations are destroyed by the large 

 intestine crossing over to the right side of the abdominal 

 cavity in front of the small intestine (duodenum), this 

 brings the small intestines to the left side of the abdominal 

 cavity. 



(7) This also brings out new attachments for the mesen- 

 tery of the large intestine (colon, ascending and transverse). 



(8) The lower (pyloric) end of the stomach and the liver 

 share in the change about, by falling over to the right side 

 of the abdominal cavity, while the spleen and the upper 

 (cardiac) end of the stomach turn to the left. Similarly, the 

 head of the pancreas turns to the right, while its tail points 

 to the left. Diags. 34, 35. 



(9) The liver is developed between the folds of the an- 

 terior mesogaster, passing from the anterior border of the 

 stomach to the diaphragm. It is connected with the 



