Malrotation of the gut

During development, the bowel rotates 270° anticlockwise in two locations: the foregut and midgut junction (duodenum) and midgut-hindgut location (cecum), so that the ligament of Treitz is located left to the midline and cecum reaches the right iliac fossa. Completeness of rotation can be classified into four cathegories:

Cathegory Description
Normal rotation Normal appearance of the gut, cecum in the right iliac fossa and the ligament of Treitz left to the midline
Incomplete rotation Incomplete rotation of the duodenum, the ligament of Treitz is absent or right to the midline, or incomplete rotation of the oral colon with formation of Ladd's bands.
Non-rotation Rotation less than 90° with absent ligament of Treitz and fixation of the cecum.
Reverse rotation Rotation in clockwise direction, extremely rare.

Classically, malrotation is also classified according to embryonic stage, in which the process was interrupted:

Type Description
Type 1 (non-rotation) Before 6th intrauterine week, when the midgut bulges into the yolk sac.
Type 2 Between the 6th and 10th intrauterine week, when the gut herniates into the umbilical cord. The large bowel remains relatively fixed, therefore malrotation at this stage involves small bowel only. It has three subtypes:
  • Type 2A: interrupted duodenal rotation with normal colonic rotation often results in formation of Ladd's bands
  • Type 2B: reverse rotation, duodenum is anteriorly and colon posteriorly to the superior mesenteric artery
  • Type 2C: reverse rotation of the duodenum and normal rotation of the colon may result in entrapment of the entire small bowel
Type 3 After 10th intrauterine week, when the midgut returns from the umbilical cord back to the abdominal cavity. During this stage, rotation of the duodenal loop is completed before the rotation of the large bowel. It has four subtypes:
  • Type 3A: the duodenum is right to the midline and cecum lies high which predisposes to volvulus
  • Type 3B: normal rotation of duodenum, but there is an incomplete attachement of the hepatic flexure often with Ladd's bands
  • Type 3C: incomplete attachement of cecum, cecum mobile
  • Type 3D: variations in peritoneal fixation of the duodenum and jejunum leading to paraduodenal hernias. This is not a true bowel malrotation.

For Criteria of midgut malrotation (volvulus, malrotation) detected on fluoroscopy in children developed by Katz, see this page.


1. Tytgat GNJ, Tytgat SHAJ. Grading and Staging in Gastroenterology.
2. Stringer BA, Babyn PS. Pediatric Gastrointestinal Imaging and Intervention.