Annular pancreas and pancreas divisum !
- Malformation
Two errors in how the pancreatic buds join: in one, tissue rings the duodenum; in the other, two ducts never connect.
Updated 2026-11-01
See it in 3D: Pancreas · Pancreatic duct · Duodenum · Common bile duct
What it is
The pancreas forms from two buds that join after the duodenum rotates. In annular pancreas, a bifid ventral bud encircles the second part of the duodenum and may narrow it. In pancreas divisum the ducts of the two buds do not fuse and most of the pancreas drains through the minor papilla. The first presents as duodenal obstruction in the newborn; the second is usually silent or appears as pancreatitis in adults.
Embryological cause
- Week 5: the dorsal and ventral pancreatic buds appear.
- Annular pancreas: the bifid ventral bud migrates in two directions around the duodenum and its halves fuse into a ring.
- Pancreas divisum: in week 7 the buds join but their ducts do not connect; the dorsal duct (of Santorini) drains almost the whole pancreas.
- Ectopic pancreas: rests of pancreatic endoderm left in the wall of the gut.
How it presents
- Annular pancreas in the newborn: vomiting, bilious or not depending on the level, prior polyhydramnios and feeding intolerance.
- Annular pancreas in adults: pain after meals, vomiting, ulcer or pancreatitis; sometimes an incidental finding.
- Pancreas divisum: usually incidental; in some people it is linked to recurrent acute or chronic pancreatitis.
- Associations of annular pancreas: Down syndrome, duodenal atresia, malrotation and heart defects.
Diagnosis
- Newborn: double bubble on X-ray, just as in duodenal atresia.
- Adult: CT or magnetic resonance cholangiopancreatography shows the pancreatic ring around the duodenum or the two separate ducts.
Test yourself
Think of the answer, then tap the question to see it.
Which pancreatic bud forms the ring in annular pancreas?
The ventral bud, which splits and encircles the second part of the duodenum.
What happens in pancreas divisum?
The ducts of the dorsal and ventral buds do not fuse, so most of the pancreas drains through the minor papilla.
Which radiographic sign can annular pancreas give in the newborn?
The double bubble, like duodenal atresia, from obstruction of the second part of the duodenum.
Which of the two anomalies is more common?
Pancreas divisum, present in about 1 in 10 people and usually without symptoms.
See it in 3D
The structures of Durgical's 3D anatomy where it is found.
Related
- Liver, gallbladder and pancreas
- Duodenal atresia and stenosis
- Foregut: esophagus, stomach rotation and duodenum
- Meckel diverticulum and other vitelline duct remnants
- Malrotation and midgut volvulus
Related conditions
Educational content on embryonic development; not a guide to prenatal diagnosis or to medicines in pregnancy and no substitute for a health professional's advice. No doses are given.
Sources: Embryology, Pancreas (StatPearls Publishing (NCBI Bookshelf), 2023); Duodenal Atresia and Stenosis (StatPearls Publishing (NCBI Bookshelf), 2023).
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Representative model, for educational purposes only.