MeSH Tree Structures
Subheadings are arranged in logical hierarchical groupings (families). For example:
- radionuclide imaging
A search of the subheading diagnosis in PubMed would automatically explode to retrieve citations indexed with the subheadings pathology, radiography, radionuclide imaging and ultrasonography.
Not all subheadings are placed in these groupings (as they do not logically fit).