Medical Subject Headings (MeSH) for literature searching in databases such as Cochrane Library and Medline.

1. MeSH Headings and
Literature Searching
Rachel Adams
Academic Support Librarian
The Library
r.adams@salford.ac.uk
http://blogs.salford.ac.uk/digital-literacy-skills/

2. • MeSH = “Medical Subject Headings”
• Created by the National Library of Medicine
• A ‘controlled vocabulary’ of pre-defined terms
• Covers all aspects of medicine and health care
• Designed in a hierarchy of terms and phrases
• Updated annually
• Used for searching databases, most notably
Medline / PubMed and Cochrane Library
What is MeSH

3. • MeSH is not the only controlled vocabulary but
it is the best known.
• Other databases use their own variations
• CINAHL uses Cinahl Headings
Controlled Vocabularies

4. MeSH ‘Trees’
A hierarchy of terms is
arranged in ‘trees’ starting
with a broad topic and
branching into more
specific ones:

5. Manually navigate the latest MeSH hierarchy:
Viewing the trees
• Search for terms at
http://www.nlm.nih.gov/mesh/MBrowser.html
• Browse through the hierarchy at
http://www.nlm.nih.gov/cgi/mesh/2014/MB_cgi
Viewing headings when search databases:
• Select to search using MeSH headings rather than just
keywords (“map term to subject headings”)
• When the list of relevant MeSH headings appears click on the
appropriate term
• You will be taken to where that term sits in the overall
hierarchy.

6. • MeSH should provide the ‘true’ meaning of a term where
a word might be used in more than 1 context.
• MeSH headings include synonyms so will search for
related terms.
• MeSH will deal with the problem of homonyms (where a
word can have more than 1 meaning)
• MeSH helps deal with problems arising from spelling
variations or errors.
• One of the biggest benefits for many people is that
MeSH can lead to finding terms not commonly used or
known. You can use it like a thesaurus to identify
alternative terms.
Benefits of using MeSH

7. • MeSH terms are best used in combination with your
own key terms
• Keywords are easy to define
• Keywords use natural language
• Keywords can deal with new techniques MeSH hasn’t
caught up with
• Takes less time to identify keywords than search for
MeSH terms
• MeSH terms might not fully represent your topic
What about keywords?

8. Using the NLM MeSH Browser:
• “ Main Headings” (Descriptors): the MeSH terms
– e.g. “diagnostic imaging”
• “ Qualifiers” (Subheadings) – aspects of a MeSH term
you can select to narrow down your results.
– e.g adverse effects
• “ Supplementary Concepts” – not part of the
controlled vocabulary
• Then choose which search option you want…
MeSH Terminology

9. Using the NLM MeSH browser
• “ Find exact term ” takes you to the entry for that term
– includes a brief definition and related terms.
• “ Find terms with all fragments ” brings a list which
includes all the terms in your search (useful when
searching for a phrase e.g. diagnostic imaging)
• “ Find terms with any fragments ” finds any words in
your search
MeSH Terminology

10. Using MeSH as a thesaurus in (OVID) Medline:
• From the search page, select “Search Tools”
• Search for your term then select one of the following:
– Map Term : maps your term to a MeSH heading (you
can then search from this point by selecting a
heading).
– Tree : see a mesh term within the overall hierarchy.
– Permuted Index : your term within the context of
similar or related terms.
– Scope Note : information about that term, including
definitions.
Mesh Terminology

11. • Select the Advanced Search option.
• Ensure “Map Term to Subject Heading” is ticked
– Enter keyword and search
• A list of possible MeSH terms appears
– “Explode” – will find that term and any more specific terms
that sit under it within the MeSH hierarchy.
– “Focus” – will search for that term but only return articles
where it considers that is the main content of the article.
• If a second screen of options appears:
– “Subheadings” – a set of categories you can narrow a
MeSH term down by – only select if genuinely relevant,
otherwise continue without selecting any.
Searching OVID Medline
using MeSH headings

12. • Now you (hopefully) understand the concept of MeSH
headings you need to apply it to your searches.
• To search effectively you need to create a search
strategy. This may include keywords and MeSH terms.
• Start by defining your terms
– Locate the key words or phrases in your question / topic.
– Consider different spellings
– Identify all the possible synonyms or alternatives for each
keyword
– Use a MeSH thesaurus to see how these key words and
phrases might map over to subject headings.
Putting it into Practice

13. PICO
A system you may find helpful when defining the topic – break
your question down under the following headings then identify all
the related terms, including MeSH headings that might also be
useful in your search:
– Patient / Population / Problem
e.g. elderly / older people / aged* / senior
– Intervention
e.g. exercise therapy* / exercise* / physical activity / exercise movement
techniques* /
– Control / Comparison
e.g. drug therapy* / pain killer / anti-inflammatory
– Outcome
e.g. pain reduction / pain measurement* / pain control / suffering* / patient
satisfaction* / quality of life*
* Denotes MeSH heading
Putting it into Practice

14. • Identify key databases to search, for example:
– Medline – all aspects of medical & health care
– Cochrane Library – includes Cochrane Database of
Systematic Review
– CINAHL – nursing and allied health literature
• Search using a combination of relevant keywords
and MeSH headings
– Combine with OR where you have related terms
(aged OR older OR senior OR geriatric…)
– Combine with AND where you want both topics
(pain killer AND low back pain)
Putting it into Practice