Katz et al. described nine findings for distinguishing normal and abnormal duodenal / jejunal positioning on upper gastrointestinal studies to detect subtle abnormalities indicative of midgut malrotation.

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: