The source and direction of thoracic lymphatics, part II: The lower thorax

The purpose of this set of 2 articles is to illustrate the source and direction of lymphatic drainage in the thorax on axial computed tomographic (CT) schematics. The first article describes the upper thorax. This article describes the lower thorax. The nodal groups are given conventional anatomic names and the corresponding terminology of the American Thoracic Society. Arrows indicate the direction of the flow. The region or organ drained is color-coded, and nodes that receive lymph from each area are assigned appropriately colored and numbered boxes. Major drainage patterns are also described. This information can be used to assess a suspicious lymph node by tracing it to the region of drainage and looking for pathology. Alternately, one may extrapolate the potential drainage routes of a tumor and scrutinize specific sites for nodal metastases.