THE DIGESTIVE APPARATUS 



1105 



and transverse portions of the large intestine. Until the fifth month the cecal 

 diverticulum has a uniform caliber, but from this time onward its distal part 

 remains rudimentary and forms the vermiform process, while its proximal part 

 expands to form the cecum. Changes also take place in the shape and position 

 of the stomach. Its dorsal part or greater curvature, to which the dorsal meso- 



Trachea J 



^Esophagus 1 



Stomach ... 



Bile-duct . 



K Lung 



I Trachea 



> Pancreas 



Bile-duct 

 Pancreas 



Lung 

 -Esophagus 



% Stomach 



\l-shaped loop of 

 small intestine - 



Vitelline duct 

 Cloaca 



FIG. 9S3. Front view of two successive stages in the development of the digestive tube. (His.) 



gastrium is attached, grows much more rapidly than its ventral part or lesser 

 curvature to which the ventral mesogastrium is fixed. Further, the greater curva- 

 ture is carried downward and to the left, so that the right surface of the stomach is 

 now directed backward and the left surface forward (Fig. 986), a change in position 



Septum transversum 



Liver 



Falciform ligament of liver 

 Lesser omentum 



Umbilical veil, 

 Umbilical cord 



Aorta 



Dorsal mesogastrium 



Stomach 



Intestinal V-shaped loop 



1 J Mesentery 



Colon 



FIQ. 984. The primitive mesentery of a six weeks' human embryo, half schematic. (Kollmann.) 



which explains why the left vagus nerve is found on the front, and the right vagus 

 on the back of the stomach. The dorsal mesogastrium being attached to the greater 

 curvature must necessarily follow its movements, and hence it becomes greatly 

 elongated and drawn lateralward and ventralward from the vertebral column, 

 and, as in the case of the stomach, the right surfaces of both the dorsal and ventral 





