1. Medical Subject Headings (MeSH)
The NLM Controlled Vocabulary
What makes MEDLINE special are the Medical Subject Headings (MeSH)
PubMed for Trainers, Fall 2015
U.S. National Library of Medicine (NLM) and NLM Training Center

2. Objectives By the end of this session, you should be able to:
Define MeSH
Explain why we use MeSH
Explain the hierarchical structure of MeSH
Explore MeSH further
Here are the objectives for this session
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3. Medical Subject Headings Defined
Represent concepts found in the biomedical literature
Like keywords on other systems
Used to describe the subject of journal articles for MEDLINE
Used for cataloging books and audiovisuals
Used by searchers
Revised annually
Gives uniformity and consistency to the indexing of the biomedical literature
MeSH headings represent concepts found in the biomedical literature
Similar to keywords on other systems
Used for indexing journal articles for MEDLINE and also used for cataloging books, audiovisuals and other library materials
Used by searchers
Revised annually
Gives uniformity and consistency to the indexing of the biomedical literature
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4. Medical Subject Headings (MeSH® Vocabulary)
MeSH Vocabulary Type
Examples
Headings
Body Weight, Kidney, Dental Cavity Preparation, Self Medication, Brain Edema, Oseltamivir
Subheadings
adverse effects, genetics, contraindications, ultrastructure
Publication Types
Letter, Review, Practice Guideline, Twin Study
Supplementary Concept Records
cordycepin, carbon monoxide dehydrogenase, nocturnin
We divide the MeSH vocabulary into four types of terms:
Headings (topics),
subheadings (further describe aspects of the topic),
publication types (describe the type of material being indexed), and
supplementary concept records
We’ve seen examples of the first three.
Supplementary Concept Records are topics that are not included as Headings in the vocabulary. The vast majority of these are substances. We’ll return to discuss supplementary concept records in a few minutes.
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5. MeSH Headings (Examples)
Lung Neoplasms
Erythrocytes
Quality of Life
Diabetes Mellitus
Ascorbic Acid
Birth Order
Glycolysis
Patient Dropouts
NLM’s MEDLINE indexers examine articles and assign the most specific MeSH heading(s) appropriate to describe the main concepts discussed.
When there is no single specific MeSH heading for a concept, the indexer will use the closest, more general MeSH heading available.
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6. MeSH Entry Terms (Example)
Lung Neoplasms
Tumors or cancer of the LUNG.
Entry Terms:
Cancer of Lung
Cancer of the Lung
Lung Cancer
Neoplasms, Lung
Neoplasms, Pulmonary
Pulmonary Cancer
Pulmonary Neoplasms
One of the features that gives value to MeSH is its use of entry terms.
Entry terms are synonymous, or close in scope, to the preferred MeSH Heading. Including the entry terms allows PubMed to account for variations in vocabulary.
If a searcher enters lung cancer or pulmonary neoplasms, the correct heading: Lung Neoplasms is brought into the search. This ensures that the relevant indexed citations are retrieved, accounting for variations in vocabulary used by the author of the article and the searcher.
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7. MeSH Tree Structure Anatomy Organisms Diseases Chemicals and Drugs
Analytical, Diagnostic and Therapeutic Techniques and Equipment
Psychiatry and Psychology
Phenomena and Processes
Disciplines and Occupations
Anthropology, Education, Sociology and Social Phenomena
Technology, Industry, Agriculture
Humanities
Information Science
Named Groups
Health Care
V. Publication Characteristics
Z. Geographicals
MeSH headings and Publication Types are arranged in a hierarchical manner called the MeSH Tree Structure
The vocabulary is organized into 16 main branches.
The most highly used or important branches are probably the first four (anatomy, organisms, diseases and chemicals and drugs).
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8. MeSH Tree in Use Reviewed 2015/10
Note that melanoma appears in 3 different locations of the tree: Neoplasms, Germ Cell and Embryonal, Neoplasms, Nerve Tissue and Nevi and Melanomas
In PubMed, a search of the broader term will automatically include more specific terms. So any narrower terms, in any branch in which they appear, will be included. This is called automatic explosion.
In this example, a search of melanoma will include Hutchison’s Melanotic Freckle, Melanoma, Amelanotic and Melanoma, Experimental.
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9. MeSH Tree in Use Reviewed 2015/10
The context, or branch of the tree, may change what narrower terms appear below it.
Here is the example, nose. Nose appears in anatomy as well as sense organs branches.
In the anatomy tree, the nose first appears as part of the face. It also appears in that same Anatomy tree, as part of the respiratory system. Under respiratory system, the nose include the nasal bone, cartilages, cavity, mucusa, etc.
In the sense organs tree, the nose include the olfactory mucosa and vomeronasal organ; the functional sensory parts of the nose.
A search of nose would “explode” to include the specific terms from both face, respiratory system, and sense organs branches.
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10. Pop Quiz (take a guess) Reviewed 2015/10 POLL:
Select all the terms that occur under the broad term Foot in the MeSH tree structure:
Ankle
Toes
Thumb
Heel
The answer is Ankle, Toes, and Heel
Ankle, Toes, and Heel are narrower terms for the term Foot. Thumb is not part of the Foot and therefore not a narrower term. Note there are other narrower terms under Foot.
Worth thinking about when you remember that PubMed automatically includes narrower terms when searching broader terms in PubMed.
A search for Foot will retrieve citations indexed with the narrower terms Ankle, Toes, and Heel as well as the other terms in this branch of the tree.
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11. Subheadings (Examples)
Lung Neoplasms/diagnosis
Erythrocytes/classification
Quality of Life/legislation and jurisprudence
Diabetes Mellitus/rehabilitation
Ascorbic Acid/secretion
Birth Order/physiology
Glycolysis/genetics
Patient Dropouts/psychology
Indexers can also assign subheadings to describe the particular aspect of a MeSH concept discussed.
Examples of Subheadings are: diagnosis, surgery, metabolism, pathology. They are included with the MeSH heading after a slash.
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12. In this example we see that the word mortality follows the heading Breast Neoplasms. In other words, the indexer has decided that this article is about mortality from Breast Neoplasms. We also see radiography following Breast Neoplasms. The indexer decided that two aspects of breast cancer are discussed: mortality, and radiography.
The MeSH terms that reflect the major points of the article are marked with an asterisk (*) by indexers, as you can see in this example…
The main emphases of this article are identified as: mortality from breast neoplasms, radiography of breast neoplasms, adverse effects of mammography, psychology of mammography, and mass screening.
In addition to assigning MeSH terms that describe the topic of the article, the indexer provides terms that reflect characteristics of the group being studied (e.g., the age group, human or other animal, male or female)
In this example we see adult, female, humans and middle aged. So we know that middle aged women are the subjects of interest.
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13. Subheading Groupings (Examples)
adverse effects
poisoning
toxicity
therapy
diet therapy
physiology
drug therapy
genetics
nursing
growth & development
prevention & control
immunology
radiotherapy
metabolism
rehabilitation
biosynthesis
surgery
blood
transplantation
cerebrospinal fluid
deficiency
enzymology
pharmacokinetics
urine
physiopathology
secretion
Subheadings have something of a hierarchy of their own.
A search of a broader subheading will automatically include the narrower subheadings.
In other words, they are exploded.
For example, a search of therapy will include diet therapy, drug therapy, radiotherapy, etc.
Use the most specific subheading to describe your topic of interest.
Where to find? Appendices in PubMed Help
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14. Publication Types (Examples)
Review
Editorial
Letter
Interactive Tutorial
Clinical Trial, Phase III
Twin Study
The indexer also describes the material represented, including the publication format (Editorial, Review) and the characteristics of the research reported by the article (clinical trial, twin study, and ). These terms are listed separately in the record under Publication Types.
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15. Publication Types in Hierarchy
Study Characteristics Clinical Study Clinical Trial Clinical Trial, Phase I Clinical Trial, Phase II Clinical Trial, Phase III Clinical Trial, Phase IV Controlled Clinical Trial
Publication Types are part of the MeSH hierarchy. This slide shows an example of the tree structure (in 2016 MeSH).
A search of a broader Publication Type will automatically include the narrower Publication Types.
In other words, they are exploded.
For example, a search for Clinical Trial [pt] will include all the narrower terms shown here.
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16. We see that this example is a meta-analysis and a review.
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17. Supplementary Concepts
Part of MeSH Database
NOT full Headings
Used to quickly add vocabulary
Substances
Protocols
Rare Diseases
MeSH includes a special subset of terms called Supplementary Concepts.
There are currently over 200,000 SCRs.
These are primarily substances, but also include some protocols and rare diseases.
New substances are identified in the literature regularly by indexers and referred to our staff chemists. These chemists verify that the substance is new to the vocabulary and add them to the database as SCRs.
Each substance is mapped to a MeSH Heading. When the supplementary concept is added to a MEDLINE record, the mapped MeSH Heading is added as well.
Use the most specific term for searching.
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18. Here’s an example of a MEDLINE record where plumbagin was applied.
Note that the mapped MeSH heading Naphthoquinones is also applied.
We’ll talk more about SCRs and how to search with them in the Drug Information presentation in Session 4.
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19. The MeSH Database Reviewed 2015/10
The MeSH Database, available from any screen in PubMed using the Database Selection menu, provides information about MeSH terms and helps you find appropriate terms for searching.
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20. The MeSH Database Reviewed 2015/10
A search of the MeSH Database is a search only of the vocabulary: You must search one concept at a time to find relevant terms.
Here are the results for a search of falls.
We’ll take a look at the term: Accidental Falls.
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21. Here is the full display format for Accidental Falls in the MeSH Database.
Following the term, a definition may be provided.
Note that this definition reflects how the term is used for indexing and cataloging.
You can use this term to search back to the earliest year displayed. In this case, it is 1987.
If you want to search the concept prior to that year, check the Previous Indexing information, below. In this example, you may want to search Accidents for literature between 1966 and 1986.
Subheadings specify which aspects of the topic have been applied to MEDLINE records.
Note the Entry Terms, below on the screen. These are synonyms that searchers can use for this topic.
You may also see a section labeled “See Also” (not on this record) which are terms related to the concept in some way and may be relevant.
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22. Below that, the MeSH hierarchy surrounding this term is displayed
Below that, the MeSH hierarchy surrounding this term is displayed. All branches of the tree where the term appears are listed.
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23. Here is a MEDLINE record (23663793)
Here is a MEDLINE record ( ). This example shows how the heading Accidental Falls was used with a number of other headings to describe a review article about the prevention of falls.
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24. Open Quiz (use the MeSH Database)
Search for the word Fragaria.
2 polls:
What are fragaria better known as?
Small pieces of glass
Birthmarks
Strawberries
Disorganized vocalizations
(Answer: Strawberries. Not much discussion on this – an exercise to have them look at the MeSH database record.)
Which of the following is NOT a subheading for Fragaria?
Adverse effects
Blood
Genetics
Virology
(Answer: Blood. This could be treated very simply with the list available in the MeSH Database, but also an opportunity to point out link to MeSH Browser and list of allowable subheadings.)
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25. Exercises
1. If you search the term Patient Acuity in PubMed, what MeSH terms are also searched?
Answer: Severity of Illness Index and Karnofsky Performance Status. This term explodes.
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26. Exercises
2. How far back can you search PubMed using the MeSH term Hand Disinfection?
Answer: You can search with a term back to the earliest date shown on the MeSH Database record under Year Introduced. If there are multiple dates, that means that something changed about the record, but there is a 1:1 relationship with the old term and the new one. For this example, Hand Disinfection was Handwashing. Because the terms are considered equivalent for MEDLINE purposes, the old term was replaced, so MEDLINE records are searchable back to the earliest use of the previous term.
If I wanted to search prior to 1982 what information on this record will help me?
Previous Indexing.
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27. Exercises
3. What ages are included in a search using the MeSH term Adolescent?
Answer: 13 to 18.
Note the other age groups. Some are “children” of others (e.g., Child, Preschool is under Child). Note also that some terms are newer than others (e.g., Frail Elderly). Be careful when using these for searching.
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28. Exercises
4. What MeSH term and Subheading combination might find relevant results about the adverse effects of bichloroacetic acid?
Answer: Dichloroacetic Acid/adverse effects or Dichloroacetic Acid/ae
Bichloroacetic acid is an entry term to dichloroacetic acid.
The PubMed syntax is heading forward slash subheading.
If you know the two letter abbreviations you can use them in place of the full subheading.
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29. Exercises 5. What type of MeSH vocabulary is the term CroFab?
Answer: CroFab is an entry term to Crotalidae Polyvalent immune Fab. Crotalidae Polyvalent immune Fab is a supplementary concept.
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30. Exercises
6. What type of MeSH vocabulary is the term Comparative Study?
Answer: Comparative Study is a publication type (PT). Specifically, it is under the Study Characteristics branch of Publication Characteristics.
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31. Exercises: BONUS QUESTION
7. What kind of term is heart attack?
Answer: This is kind of a trick question. If you search the MeSH Database, you’ll find that “heart attack” isn’t in MeSH at all. But if you search PubMed, you see that it maps to Myocardial Infarction. This “trickery” (aka: a great feature of PubMed!) is enabled by the use of the Unified Medical Language System (UMLS), which allows PubMed to use terms from a wide range of medical vocabularies to map to MeSH.
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32. Useful My NCBI features to use when searching with MeSH
Click here
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33. Open Abstract Supplemental Data in My NCBI
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34. Use of My NCBI /highlighting when searching with MeSH
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35. Highlighting and open supplemental data
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36. Summary
MeSH is NLM's controlled vocabulary for subject indexing and searching MEDLINE/PubMed
There are four types of MeSH:
Headings
Subheadings
Publication Types
Supplementary Concept Records
MeSH uses synonyms known as Entry terms
MeSH is organized in a hierarchy or tree
Indexers designate the major points of articles as MeSH Major Topics
Use the MeSH Database to find MeSH terms
Use My NCBI Site Preferences to customize PubMed displays
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37. Questions?
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