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WHSL Medical Subject Headings for PubMed Searching: MeSH Trees

This guide will assist you to use the Medical Subject Headings (MeSH) when you are searching in PubMed

Example of a MeSH Tree

If you search for "high blood pressure" in MeSH, you will see that the correct MeSH term for this condition is "hypertension". Terms in MeSH have a brief definition to allow you to choose the correct MeSH term. The definition for hypertension is:

"Persistently high systemic arterial BLOOD PRESSURE. Based on multiple readings (BLOOD PRESSURE DETERMINATION), hypertension is currently defined as when SYSTOLIC PRESSURE is consistently greater than 140 mm Hg or when DIASTOLIC PRESSURE is consistently 90 mm Hg or more".

Terms that are printed in CAPITAL LETTERS are in turn other MeSH terms that you can use to search PubMed.

The MeSH tree display allows you to:

  • See subject headings in their hierarchical context, showing broader and narrower terms
  • See surrounding headings, ensuring that the term which matches the query most closely, is selected
  • Display subject headings in all contexts

MeSH Tree for Hypertension

The MeSH term hypertension falls under the Category of Diseases (C) in the tree structure. Diseases Category is therefore the highest ranked (broadest, or least specific) term in the tree. Within the category of Diseases, hypertension falls under the more specialised (narrower) category of Cardiovascular Diseases. Even more specific, is the category of Vascular Diseases, and hypertension is a specific form of Vascular Disease.

The condition of hypertension itself can be further classified into more and more specific types of hypertension, such as malignant hypertension, pregnancy-induced hypertension, renal hypertension and hypertensive retinopathy. Renovascular hypertension is a more specific condition than, but still related to, renal hypertension

Diseases Category

   Cardiovascular Diseases

      Vascular Diseases


            Hypertension, Malignant

            Hypertension, Pregnancy-Induced

            Hypertension, Renal

                   Hypertension, Renovascular

            Hypertensive Retinopathy

The term you used in your search, hypertension, is printed in bold type. Narrower (more specific) terms are lower on the tree and are indented. Thus, Hypertension, Renovascular is more specific (narrower) than Hypertension, Renal. You should always search using the most specific term that applies to your query.

When PubMed searches a MeSH term, it will automatically include narrower terms in the search. When you search PubMed, all related concepts are "mapped" or pulled together by using MeSH, and your search will become more accurate.

Entry Terms

The controlled vocabulary term hypertension is used to cover other keywords that have been used to describe the same condition. These are called "entry terms". If you click on the hyperlink hypertension in MeSH, you will see under the terms and subheadings,  the "entry terms"

  • Blood Pressure, High
  • Blood Pressures, High
  • High Blood Pressure
  • High Blood Pressures
In effect, by clicking on a single term, hypertension, you are also searching for the four variant (synonymous) terms or keywords listed above as well.




MeSH Tree Exercises

Open the links below to compare the MeSH Trees for the terms anaemia, pernicious anaemia and iron deficiency anaemia. Remember to use the American spelling anemia. You also need to scroll to the bottom of the MeSH entry page to see the MeSH tree for each term.

  • Are these terms the same?
  • Do these terms cover the same conditions?
  • What is another term for Pernicious Anemia?
  • Which is a narrower term than Anemia in the same MeSH Tree branch?
  • What does the + sign after a term mean (eg. Anemia, Hypoplastic, Congenital +)?


MeSH Exercise

  1. Use MeSH in PubMed to determine the best term to use if you are searching for the concept of fainting. (Scroll to the bottom of the screen to see the MeSH trees for this topic).
  2. Use MeSH to search for the concept of dizziness. (Scroll to the bottom of the screen to see the MeSH trees for this topic. You will need to click on the term itself to see the MeSH trees).
  3. Based on the definitions provided for each term, are these conditions the same?