What is Medical Subject Headings?

Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. Created and updated by the United States National Library of Medicine (NLM), it is used by the MEDLINE/PubMed article database and by NLM's catalog of book holdings. MeSH can be browsed and downloaded free of charge on the Internet. The yearly printed version was discontinued in 2007.

In MEDLINE/PubMed, every journal article is indexed with some 10-15 headings or subheadings, with one or two of them designated as major and marked with an asterisk. When performing a MEDLINE search via PubMed, entry terms are automatically translated into the corresponding descriptors (see Details tab in PubMed). Furthermore, by default all the descriptors below the given one in the hierarchy are included in the search.

Structure of MeSH

The 2005 version of MeSH contains a total of 22,568 subject headings, also known as descriptors. Most of these are accompanied by a short definition, links to related descriptors, and a list of synonyms or very similar terms (known as entry terms). Because of these synonym lists, MeSH can also be viewed as a thesaurus.

Descriptors

The descriptors are arranged in a hierarchy. A given descriptor may appear at several places in the hierarchical tree. The tree locations carry systematic labels known as tree numbers, and consequently one descriptor can carry several tree numbers. For example, following the graphic at the top right, C stands for Diseases, C06 for Digestive System Diseases and C06.301 for Digestive System Neoplams; C04 for Neoplasms, C04.588 for Neoplasms By Site, and C04.588.274 is a second tree number for Digestive System Neoplasms. As seen from the graphic, Stomach Neoplasms appears in four locations in the hierarchy and therefore carries four different tree numbers. The tree numbers of a given descriptor are subject to change as MeSH is updated. Every descriptor also carries a unique alphanumerical ID that will not change.

Description

Most entries come with a short description. See the MeSH description for diabetes type 2 as an example. The explanatory text is written by the MeSH team based on their standard sources [1] if not otherwise stated. References are mostly encyclopaedias and standard textbooks of the subject areas. Sources are subdivided into categories (based on what?). However, references for specific statements in the descriptions are not given, instead readers are referred to the bibliography.

Qualifiers

In addition to the descriptor hierarchy, MeSH contains a small number of standard qualifiers (also known as subheadings), which can be added to descriptors to narrow down the topic. For example, "Measles" is a descriptor and "epidemiology" is a qualifier; "Measles/epidemiology" describes the subheading of epidemiological articles about Measles. The "epidemiology" qualifier can be added to all other disease descriptors. Not all descriptor/qualifier combinations are allowed since some of them may be meaningless. In all there are 83 different qualifiers.

Supplements

In addition to the descriptors, MeSH also contains some 139,000 Supplementary Concept Records. These do not belong to the controlled vocabulary as such and are not used for indexing MEDLINE articles; instead they enlarge the thesaurus and contain links to the closest fitting descriptor to be used in a MEDLINE search. Many of these records describe chemical substances.

MeSH has been translated into numerous other languages and allows retrieval of documents from different languages.

Top level categories

The top level categories in the MeSH descriptor hierarchy are:

• Anatomy [A]
• MeSH A01 --- body regions
• MeSH A02 --- musculoskeletal system
• MeSH A03 --- digestive system
• MeSH A04 --- respiratory system
• MeSH A05 --- urogenital system
• MeSH A06 --- endocrine system
• MeSH A07 --- cardiovascular system
• MeSH A08 --- nervous system
• MeSH A09 --- sense organs
• MeSH A10 --- biological tissues
• MeSH A11 --- cells
• MeSH A12 --- fluids and secretions
• MeSH A13 --- animal structures
• MeSH A14 --- stomatognathic system
• MeSH A15 --- hemic and immune systems
• MeSH A16 --- embryonic structures
• MeSH A17 --- integumentary system
• organisms [B]
• MeSH B01 --- animals
• MeSH B02 --- algae
• MeSH B03 --- bacteria
• MeSH B04 --- viruses
• MeSH B05 --- fungi
• MeSH B06 --- plants
• MeSH B07 --- archaea
• MeSH B08 --- mesomycetozoea
• Diseases [C]
• MeSH C01 --- bacterial infections and mycoses
• MeSH C02 --- virus diseases
• MeSH C03 --- parasitic diseases
• MeSH C04 --- neoplasms
• MeSH C05 --- musculoskeletal diseases
• MeSH C06 --- digestive system diseases
• MeSH C07 --- stomatognathic diseases
• MeSH C08 --- respiratory tract diseases
• MeSH C09 --- otorhinolaryngologic diseases
• MeSH C10 --- nervous system diseases
• MeSH C11 --- eye diseases
• MeSH C12 --- urologic and male genital diseases
• MeSH C13 --- female genital diseases and pregnancy complications
• MeSH C14 --- cardiovascular diseases
• MeSH C15 --- hemic and lymphatic diseases
• MeSH C16 --- congenital, hereditary, and neonatal diseases and abnormalities
• MeSH C17 --- skin and connective tissue diseases
• MeSH C18 --- nutritional and metabolic diseases
• MeSH C19 --- endocrine system diseases
• MeSH C20 --- immune system diseases
• MeSH C21 --- disorders of environmental origin
• MeSH C22 --- animal diseases
• MeSH C23 --- pathological conditions, signs and symptoms
• Chemicals and Drugs [D]
• MeSH D01 --- inorganic chemicals
• MeSH D02 --- organic chemicals
• MeSH D03 --- heterocyclic compounds
• MeSH D04 --- polycyclic compounds
• MeSH D05 --- macromolecular substances
• MeSH D06 --- hormones, hormone substitutes, and hormone antagonists
• MeSH D08 --- enzymes and coenzymes
• MeSH D09 --- carbohydrates
• MeSH D10 --- lipids
• MeSH D12 --- amino acids, peptides, and proteins
• MeSH D13 --- nucleic acids, nucleotides, and nucleosides
• MeSH D20 --- complex mixtures
• MeSH D23 --- biological factors
• MeSH D25 --- biomedical and dental materials
• MeSH D26 --- pharmaceutical preparations
• MeSH D27 --- chemical actions and uses
• Analytical, Diagnostic and Therapeutic Techniques and Equipment [E]
• MeSH E01 --- diagnosis
• MeSH E02 --- therapeutics
• MeSH E03 --- anesthesia and analgesia
• MeSH E04 --- surgical procedures, operative
• MeSH E05 --- investigative techniques
• MeSH E06 --- dentistry
• MeSH E07 --- equipment and supplies
• Psychiatry and Psychology [F]
• MeSH F01 --- behavior and behavior mechanisms
• MeSH F02 --- psychological phenomena and processes
• MeSH F03 --- mental disorders
• MeSH F04 --- behavioral disciplines and activities
• Biological Sciences [G]
• MeSH G01 --- biological sciences
• MeSH G02 --- health occupations
• MeSH G03 --- environment and public health
• MeSH G04 --- biological phenomena, cell phenomena, and immunity
• MeSH G05 --- genetic processes
• MeSH G06 --- biochemical phenomena, metabolism, and nutrition
• MeSH G07 --- physiological processes
• MeSH G08 --- reproductive and urinary physiology
• MeSH G09 --- circulatory and respiratory physiology
• MeSH G10 --- digestive, oral, and skin physiology
• MeSH G11 --- musculoskeletal, neural, and ocular physiology
• MeSH G12 --- chemical and pharmacologic phenomena
• MeSH G13 --- genetic phenomena
• MeSH G14 --- genetic structures
• Physical Sciences [H]
• MeSH H01 --- natural sciences
• Anthropology, Education, Sociology and Social Phenomena [I]
• MeSH I01 --- social sciences
• MeSH I02 --- education
• MeSH I03 --- human activities
• Technology and Food and Beverages [J]
• MeSH J01 --- technology, industry, and agriculture
• MeSH J02 --- food and beverages
• Humanities [K]
• MeSH K01 --- humanities
• Information Science [L]
• MeSH L01 --- information science
• Persons [M]
• MeSH M01 --- persons
• Health Care [N]
• MeSH N01 --- population characteristics
• MeSH N02 --- health care facilities, manpower, and services
• MeSH N03 --- health care economics and organizations
• MeSH N04 --- health services administration
• MeSH N05 --- health care quality, access, and evaluation
• Publication Characteristics [V]
• MeSH V01 --- publication components (publication type)
• MeSH V02 --- publication formats (publication type)
• MeSH V03 --- study characteristics (publication type)
• MeSH V04 --- support of research
• Geographic Locations [Z]
• MeSH Z01 --- geographic locations

See also

• Medical literature retrieval
• Medical classification
• Controlled vocabulary
• MEDLINE
• MeshPubMed - Explore PubMed/MEDLINE with Medical Subject Headings (MeSH)
• Wikipedia:MeSH

External links

• Medical Subject Heading Home provided by National Library of Medicine, National Institutes of Health (U.S.)
• MeSH database tutorials
• Browsing MeSH:
• Through Entrez
• Through MeSH Browser
• List of qualifiers - 2005
• MeSH search using KMLE Medical Dictionary