Infant with bilious vomiting AP image from an upper GI (left) shows the ligament of Treitz projecting over the right pedicle of the L2 vertebral body and to be lower in position than the duodenal bulb that projects over the right pedicle of the L1 vertebral body. The spiral appearance of the proximal jejunum is best appreciated on the lateral image (right). The diagnosis was malrotation with midgut volvulus.