Duodenal development
From WikiLectures
The duodenum arises from the terminal part of the front intestine and part of the middle intestine - the border is below the opening of the ductus choledochus. Due to the rotation of the stomach, the duodenum takes the shape of the letter C and turns to the right. Like the pancreas, it finds itself in the retroperitoneum (except for the pars superior duodenum).
During the 2nd month, the lumen of the duodenum is temporarily closed due to the proliferation of enterocytes, but after several apoptosis it opens again.
The front intestine supplies the truncus coeliacus, the middle intestine the superior mesenteric artery → duodenum therefore has a double supply.