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Medical Subject Headings (MeSH)
Dr. Yan Ma
Medical Subject Headings
MeSH is designed and used by the National Library of Medicine. It was first based on LCSH, but it is quite different from LCSH now. In the 1950s, MeSH started to develop its own format. MeSH is now has two versions: 1. Index Medicus MeSH for indexing journal articles. 2. Annotated MeSH that is used by indexers and catalogers.
Medical Subject Headings
MeSH appears in 3 volumes:
1. Medical Subject Headings--Annotated Alphabetic List.
2. Medical Subject Headings--Tree Structures.
3. Permuted Medical Subject Headings.
Medical Subject Headings
1. MeSH annotated list: contains main headings and topical and form subheadings with notes and cross-references. Subheadings and instruction on their use are listed separately rather than under the main headings with which they may be used.
Medical Subject Headings
Pre-explosions pre-stores all the citations that are normally retrieved in an online EXPlode command. Seventy-three MeSH headings requiring excessive computer time to explore in NLM’s retrieval system can be searched as “pre-explosions.” Pre-explosions are from the tree structures. So, they are all narrower terms.
Medical Subject Headings
Form, geographic, and language subheadings used in cataloging are listed separately in Appendixes A to C.
Medical Subject Headings
2. MeSh Tree Structures: consists of a categorical arrangement placing headings in relationship to other headings that represent similar areas and concepts. A system of tree numbers (capital letter followed by one or more strings of numbers) is used to reflect the hierarchies.
MeSH Tree Structure: 15 Major Categories:
A Anatomy
B Organisms
C Diseases
D Chemical and Drugs
E Analytical, Diagnostic, and Therapeutic Techniques and Equipment
F Psychiatry and Psychology
MeSH Tree Structure: 15 Major Categories:
G Biological Sciences
H Physical Sciences
I Anthropology, Education, Sociology and Social Phenomena
J Technology, Industry, Agriculture
K Humanities
L Information Sciences
MeSH Tree Structure: 15 Major Categories:
M Named Groups
N Health Care
Z Geographical
MeSH Tree Structure
The tree structure provides a classificatory approach to medical subject headings, manifesting the hierarchical structure of the subject headings and providing a logical basis for the cross-references. In online system, the tree numbers, also called descriptor codes, can be used to retrieve related subjects.
Medical Subject Headings
3. Permuted Medical Subject Headings: is a keyword index listing each significant word in the subject heading phrase or cross-reference regardless of its position in the phrase.
Structure of MeSH Headings
Structure of Headings:
Major descriptors or main headings represent the main topics. Most of the main headings are in the form of single words or phrases.
Structure of MeSH Headings
There are other types of main headings such as publication types or citation types. They include such terms as ABSTRACT, BIBLIOGRAPHY, CONGRESS. A publication-types main heading characterizes what a publication is rather than what it is about.
Structure of MeSH Headings
Some headings are only for indexing purposes. For example, HUMAN (check tag only, CATALOG: do not use. for indexers only), ANIMAL is another example.
Structure of MeSH Headings
Sometimes a main heading is coded NON-MESH.
This means that it is not used in indexing or cataloging but serves to group headings in the MeSH Tree Structures.
MeSH Subheadings
It is called Subheadings, NOT Subdivisions in LCSH
MeSH Subheadings
There are four types of subheadings: topical, form, geographic, and language. The latter three are used only in cataloging and not in indexing.
MeSH Cross-References
There are two categories of references in MeSH: see reference and related concept indicators.
Example: vidine see choline
MeSH Cross-References
Reciprocal entries are indicated by the symbol X.
choline
x vidine
MeSH Cross-References
There are 2 types of related concept indicators: see related and consider also. The see related references are used to indicate the presence of other headings that relate to the topic conceptually.
CHILD DAY CARE CENTERS
see related
NURSERIES
MeSH Cross-References
Reciprocals are printed under the related headings, indicated by the symbol X
NURSERIES
XR CHILD DAY CARE CENTER
MeSH Cross-References
The consider also reference was instituted in 1991. It indicates the presence of the other headings that relate to the topic linguistically. They are primarily used with anatomic headings. A consider also reference refers to groups of headings beginning with a common word stem.
MeSH Cross-References
HEART
consider also at CARDI- AND MYOCARDI-
Assigning MeSH Headings
If the work contains more than one concept, catalogers may apply one or more of the three following methods:
1. using two or more main headings.
2. using a pre-coordinated main heading.
3. using a main heading and a subheading, including topical, geographic, form, or language subheading.
Assigning MeSH Headings
If a publication deals with 2 or more subjects that are subordinate to a broad heading, up to 3 separate and specific headings are assigned.
Assigning MeSH Headings
If more than 3 subjects are involved, the broad heading encompassing the individual specific topics in the tree structure is assigned.
If the specific subjects are not within the tree, as many specific headings as necessary are assigned.
Assigning MeSH Headings
For example: a book that deals with aloe, coca, ginseng, mustard as medicine. The broad heading PLANTS, MEDICINAL is assigned.
PLANT, MEDICINAL B6.560
Aloe B6.560.77
Coca B6.560.216
Ginseng B6.560.434
Mustard B6.560.610
Assigning MeSH Subheadings
A main heading may be divided by topical, geographic, form, and or language subheadings.
Assigning MeSH Subheadings
Topical:
No more than 3 topical subheadings are assigned under a given main heading. When more than 3 topical subheadings are applicable, the main heading is assigned without topical subheading.
Assigning MeSH Subheadings
Geographic:
There is a list of geographic locations in Appendix B. Geographic subheadings are used only when the usage is indicated under the main heading in the list specify geog or CATALOG: /geog/form.
Assigning MeSH Subheadings
Unlike LCSH, geographic subheadings always appear directly in MeSH.
COMMUNITY HEALTH SERVICES--BOSTON(MeSH)
COMMUNITY HEALTH SERVICES--MASSACHUSETTS--BOSTON. (LCSH)
Assigning MeSH Subheadings
Only 1 geographic subheading is allowed. If your need 2, use 2 separate headings.
If more than 3 geographic areas are involved, and all of which are within a larger area, the subheading for the larger area is used.
Dental Care--Midwestern United States.
Assigning MeSH Subheadings
There are exceptions: page I-149
epidemiology, prevention & control
Even a main heading is not annotated for geographic subheading, but when it is combined with certain topical headings, such as those listed above, the subject may have a geographic emphasis.
Assigning MeSH Subheadings
Examples:
Kidney Diseases--epidemiology--New York City.
Neoplasms--prevention & control--United States.
Assigning MeSH Subheadings
There are 3 form headings that may imply geographic consideration:
directories
legislation
statistics
Assigning MeSH Subheadings
Form Subheadings:
Form subheadings are used to indicate the form of the overall publication and are generally assigned to all subject headings for a particular publication. If more than 2 form subheadings which are not pre-coordinated in the list apply to a particular publication, the main heading is repeated with individual form subheadings.
Assigning MeSH Subheadings
Examples:
Dental Care--United States--directories
Dental Care--United States--handbooks
Assigning MeSH Subheadings
Language Subheadings:
Appendix C is a list of languages.
When more than 1 type of subheading is applied to a main heading, the citation order of subheadings:
main heading—topical—geographic—form-- language subheadings
Assigning MeSH Subheadings
Few headings contain 4 subheadings since language subheadings are extremely limited in application.
Assigning MeSH Subheadings
Topical Subheadings Allowable Categories
The tree number indicated in the main heading serves a category purpose when assigning a subheading.
Comparisons of LCSH, Sears, and MeSH
LCSH is designed and used for LC and other large libraries in US.
Sears is used for small and medium size libraries.
MeSH is used for medical materials in the US and other countries. That is especially true with Medline.
Comparisons of LCSH, Sears, and MeSH
Syntax of headings: similar
MeSH has tree numbers, notes for cataloging.
Both LCSH and Sears use BT, RT, NT, etc.
MeSH uses X, XR, See related, also consider.
Comparisons of LCSH, Sears, and MeSH
Subdivision:
LSCH: subdivisions are listed or listed in the free-floating subdivision list
There are pattern headings.
Comparisons of LCSH, Sears, and MeSH
Subdivision:
Sears: Key headings or Headings to be Added by the Cataloger
There is a list of Commonly Used Subdivisions for the Cataloger to add.
Comparisons of LCSH, Sears, and MeSH
Topical subdivision/subheadings:
LCSH and Sears: in the list
MeSH: Use them according to the allowable categories.
Comparisons of LCSH, Sears, and MeSH
Form subdivision/subheadings:
LCSH: there is a free-floating subdivision list
Format subdivisions are indicated in the free-floating subdivision index.
MeSH: there is a list of form subheadings such as CD-ROMs, videocassette, ect.
Comparisons of LCSH, Sears, and MeSH
Geographic subdivision/subheading:
LSCH: by larger geographic region or jurisdiction except US. Britain, and Canada.
MeSH: use the most specific if instructed.
Comparisons of LCSH, Sears, and MeSH
Language subheading:
In MeSH, there is a category of language as subheading.
Comparisons of LCSH, Sears, and MeSH
MARC Tagging:
650 0 is for LCSH
650 2 is for MeSH
650 8 is for Sears