[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Embryology](https://durgical.com/en/embryology/) › [Digestive system](https://durgical.com/en/embryology/#a-digestive) › Jejunal and ileal atresia [Embryology](https://durgical.com/en/embryology/) · [Digestive system](https://durgical.com/en/embryology/#a-digestive) # Jejunal and ileal atresia - Malformation A stretch of small bowel is missing or closed because it lost its blood supply before birth; the newborn vomits bile and becomes distended. Updated 2026-11-01 **See it in 3D:** [Jejunum](https://durgical.com/en/anatomy/jejunum/) · [Ileum](https://durgical.com/en/anatomy/ileum/) · [Superior mesenteric artery](https://durgical.com/en/anatomy/superior-mesenteric-artery/) ## Key points - Cause: intrauterine ischaemia from injury to mesenteric branches (volvulus, intussusception, gastroschisis), not failed recanalization. - Types I to IV; type IIIb or 'apple peel' results from absence of the distal superior mesenteric artery, with the ileum coiled around a single artery. - Bilious vomiting on the first day and distension, greater the more distal the atresia. - X-ray: several bubbles (triple bubble in high jejunal atresia) and no distal gas. - Contrast enema: microcolon from disuse. - Associations: gastroschisis, cystic fibrosis (meconium ileus) and malrotation; less tied to chromosomal disorders than duodenal atresia. ## What it is Jejunoileal atresia is a congenital interruption of the small bowel lumen. Unlike duodenal atresia, it is caused by an intrauterine vascular accident in mesenteric branches: the segment that loses its blood supply necroses and is resorbed after the bowel has already formed. It is a common cause of neonatal bowel obstruction and is associated with gastroschisis, intrauterine volvulus and cystic fibrosis. ## Embryological cause - After the bowel has formed and recanalized, a volvulus, intussusception, internal hernia or the constriction of a gastroschisis compresses mesenteric branches. - The ischaemic segment necroses and is resorbed, leaving a membrane, a fibrous cord or a gap in the mesentery. - Type IIIb: occlusion of the distal superior mesenteric artery; the distal ileum coils around an ileocolic artery. - Type IV: multiple atresias along the bowel. ## How it presents - Bilious vomiting in the first 24 hours. - Abdominal distension, more marked in distal atresias. - No meconium, or only mucus plugs. - Polyhydramnios in proximal atresias. - History of gastroschisis, intrauterine volvulus or cystic fibrosis. ## Diagnosis - Prenatal ultrasound: dilated loops and polyhydramnios. - X-ray: dilated proximal loops with fluid levels and no distal gas; triple bubble in high jejunal atresia. - Contrast enema: microcolon; helps separate it from meconium ileus and Hirschsprung disease. - In ileal atresia, cystic fibrosis is investigated (sweat test or genetics). ## Memory aid The duodenum's tunnel never reopened; the jejunum and ileum had their water main cut. Duodenum fails to hollow, the small bowel fails to be fed. ## Test yourself Think of the answer, then tap the question to see it. ## What mechanism causes jejunoileal atresia? An intrauterine vascular accident in mesenteric branches that kills an already formed segment, which is then resorbed. ## How does it differ from duodenal atresia? Duodenal atresia comes from failed recanalization and is linked to Down syndrome; jejunoileal atresia is ischaemic and rarely chromosomal. ## What is apple peel atresia? Type IIIb: the distal superior mesenteric artery is missing and the ileum spirals around a single artery. ## Which genetic disease is investigated in a newborn with ileal atresia? Cystic fibrosis, because meconium ileus can cause volvulus and ileal atresia. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/embryology/jejunal-and-ileal-atresia/) ## See it in 3D The structures of Durgical's 3D anatomy where it is found. - [Jejunum](https://durgical.com/en/anatomy/jejunum/) - [Ileum](https://durgical.com/en/anatomy/ileum/) - [Superior mesenteric artery](https://durgical.com/en/anatomy/superior-mesenteric-artery/) ## Related - [Duodenal atresia and stenosis](https://durgical.com/en/embryology/duodenal-atresia-and-stenosis/) - [Omphalocele and gastroschisis](https://durgical.com/en/embryology/omphalocele-and-gastroschisis/) - [Malrotation and midgut volvulus](https://durgical.com/en/embryology/malrotation-and-midgut-volvulus/) - [Midgut: physiological herniation and rotation](https://durgical.com/en/embryology/midgut-physiological-herniation-and-rotation/) - [Hirschsprung disease (congenital aganglionic megacolon)](https://durgical.com/en/embryology/hirschsprung-disease/) - [Amniotic fluid: polyhydramnios and oligohydramnios](https://durgical.com/en/embryology/amniotic-fluid-polyhydramnios-and-oligohydramnios/) ## Related conditions - [Cystic fibrosis](https://durgical.com/en/conditions/cystic-fibrosis/) [← All of embryology](https://durgical.com/en/embryology/) 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: [Ileal Atresia](https://www.ncbi.nlm.nih.gov/books/NBK557400/) (StatPearls Publishing (NCBI Bookshelf), 2023); [Embryology, Midgut](https://www.ncbi.nlm.nih.gov/books/NBK553156/) (StatPearls Publishing (NCBI Bookshelf), 2023). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/embryology/jejunal-and-ileal-atresia/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/embryology/jejunal-and-ileal-atresia/