The spine as a point of reference for duodenal displacement by an enlarged liver in the sagittal projection.

Normally, in the sagittal projection, the descending duodenum is situated to the right of the spine. There is a great range of variation in its position, so that a slight medial displacement by an enlarged liver or a mass adjacent to the latter cannot be diagnosed unless either an extrinsic pressure effect is demonstrated or a previous study is available for comparison. On a single study, displacement of the duodenum by an enlarged liver is suspected whenever the descending duodenum overlies the spine. This position is more indicative of displacement in sthenic than in asthenic individuals.