351217.fig.004a
(a)
351217.fig.004b
(b)
Figure 4: (a) Annular pancreas might be formed when the left ventral pancreatic anlage persists, and the right ventral pancreatic anlage does not rotate around the duodenum. The two ventral anlagen encircle the duodenum. (b) Pancreas divisum. After the left ventral anlage disappears, the right ventral anlage rotates around the duodenum and fuses the dorsal anlage. The ventral and dorsal pancreatic ducts fail to fuse together. RVP, right ventral pancreatic anlage; LVP, left ventral pancreatic anlage; DP, dorsal pancreatic anlage.