Editing Duodenum (section)

===Variation===
The duodenum's close anatomical association with the pancreas creates differences in function based on the position and orientation of the organs. The congenital abnormality, annular pancreas, causes a portion of the pancreas to encircle the duodenum. In an extramural annular pancreas, the pancreatic duct encircles the duodenum which results in gastrointestinal obstruction. An intramural annular pancreas is characterized by pancreatic tissue that is fused with the duodenal wall, causing duodenal ulceration.<ref>{{Cite journal |last1=Borghei |first1=Peyman |last2=Sokhandon |first2=Farnoosh |last3=Shirkhoda |first3=Ali |last4=Morgan |first4=Desiree E. |date=January 2013 |title=Anomalies, Anatomic Variants, and Sources of Diagnostic Pitfalls in Pancreatic Imaging |url=http://pubs.rsna.org/doi/10.1148/radiol.12112469 |journal=Radiology |language=en |volume=266 |issue=1 |pages=28–36 |doi=10.1148/radiol.12112469 |pmid=23264525 |issn=0033-8419|url-access=subscription }}</ref>{{expand section|date=December 2013}}