Z-shaped duodenojejunal loop: sign of mesenteric fixation anomaly and congenital bands.

Four children (ages 3-9 years) with intermittent abdominal pain and vomiting are reported. Upper gastrointestinal examinations revealed a sharply angulated to-and-fro course (Z configuration) of the distal duodenum and proximal jejunum, rather than the usual smooth duodenojejunal loop at the ligament of Treitz. At operation this configuration was associated with broad peritoneal bands extending across the involved small intestine without an accompanying volvulus at this level. The Z sign is diagnostic of incomplete rotation, even in the absence of duodenal obstruction and with a proximal jejunum that may appear to be properly placed.