Introduction to the Medical Subject Headings (MeSH^® Vocabulary)

What is MeSH?

• Acronym for Medical Subject Headings
• The U.S. National Library of Medicine's controlled vocabulary (thesaurus)
• Gives uniformity and consistency to the indexing and cataloging of biomedical literature and is a distinctive feature of MEDLINE
• Similar to keywords on other systems
• Arranged in a hierarchical manner called the MeSH Tree Structures
• Updated annually

Who uses MeSH?

• Searchers of MEDLINE/PubMed, library catalogs, and other databases -- to assist with subject searching
• National Library of Medicine (NLM) indexers -- to describe subject content of journal articles for MEDLINE
• Catalogers -- to describe books and audiovisuals in the NLM and other medical library collections (see the Using Medical Subject Headings (MeSH®) in Cataloging online training course)

MeSH Vocabulary includes four types of terms:

• Headings — over 26,000 headings represent concepts found in the biomedical literature

• Subheadings — (also called qualifiers) attached to MeSH headings to describe a specific aspect of a concept

Note: See Subheading Hierarchical Groupings

• Supplementary Concept Records — over 197,000 terms in a separate thesaurus from the Medical Subject Headings. These are primarily substance terms, but also include some protocols and rare disease terms. These terms are updated weekly.

• Publication Characteristics (Publication Types) — describe the type of publication being indexed; i.e., what the item is, not what the article is about