Medical subject headings (MeSH) are preferred vocabulary used to index citations in PubMed. Subject headings standardize definitions, variants in spelling and terminology, and related terms. When a citation is indexed in PubMed, the citation record is tagged with the subject headings most reflective of the citation content.
Components of a MeSH record:
Scope: How the database defines a concept
Year introduced: The year the database began using a subject heading
Subheadings: Optional subheadings to narrow and focus the PubMed search
Restrict to MeSH Major Topic: Limits search to citations for which the subject heading is a major focus
Do not include MeSH terms found below this term in the MeSH hierarchy: By selecting this option, any terms that are more narrow than the chosen term are not included in a search.
Entry terms: Alternate terms, spellings, and acronyms for a subject heading
Previous Indexing: Terms used for a subject heading in the past
MeSH Hierarchy: A hierarchy or tree of concepts from broadest to narrowest
