302 



EMBRYOLOGY. 



The duodenum, describing the well-known horseshoe-sliaped curve, 

 applies its mesentery, in which the beginning of the pancreas is en- 

 closed, broadly to the posterior wall of the body, and fuses throughout 

 its whole extent with the peritoneum of the latter; from being 

 a movable it has become an immovable portion of the intestine 

 (fig. 167 du). 



The large intestine (figs. 165 and 167 A and £ ct) still possesses in 

 the third month a very broad suspensorium arising from the vertebral 

 column, which is nothing else than a part of the common mesentery 



rig. 167 A B.— Two diagiams to illustrate the development of the bursa omentalis. 



A, earlier, B, later stage. 



2/, Diaphragm ; Z, liver ; ^, pancreas ; mg, stomach ; gc, its greatea: curvature ; du, duodenum ;, 

 dd, small intestine ; ct, colon transversum ; *, bursa omentalis ; kn, lesser omentum ; 

 gn^, posterior [dorsal] lamella of the greater omentum, arising from the vertebral column ; 

 gn', anterior [ventral] lamella of the same, attached to the greater curvature of the stomach 

 (gc) ; gv?, the part of the omentum which has grown over the small intestine ; gn*, the 

 part of the omentum which encloses the pancreas ; Tries, mesentery of the small intestine 7 

 msc, mesocolon of the transverse colon. 



of the intestine, but which has received the special designation of 

 mesocolon {msc). In consequence of the previously described twisting 

 of the primitive loop of the intestine, not only the colon trans- 

 versum, but also the considerable mesocolon belonging to it, has been 

 drawn transversely across the end of the duodenum ; for a certain 

 distance it fuses with the latter and with the posterior wall of the 

 body, thereby acquires a new secondary line of attachment (fig. 167 

 mso) running from right to left, and thus appears as a part that has 

 become detached from the common mesentery. The colon transversum 

 (ct) with its mesocolon (msc) now divides the body-cavity into an. 



