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Medical Subject Headings

Use Of Medical Subject Headings For Cataloging - 2007

With few exceptions, catalogers apply the same basic principles as those used by indexers in assigning MeSH terms for the subject analysis of bibliographic materials. Below are instructions for the correct coordination of main headings and subheadings, and assignment of publication types for cataloging. Included are instructions for medical catalogers on how to construct the traditional subject heading string no longer used on NLM's internal bibliographic records, along with a discussion of changed practices since 2006.

  • Background
  • Cataloging Annotations
  • Specific Headings vs. Broader Headings
  • Topical Subheadings
  • Headings Not used in Subject Cataloging
  • Creating traditional subject strings in a local catalog
  • Changes in Subject Heading Structure, Content and Practice -
    • Age Group Headings & PREGNANCY
    • Publication Types

Background

The Cataloging Section at NLM uses the Medical Subject Headings (MeSH) thesaurus for assigning subject headings to materials in all formats. Catalogers follow the same principles for application of MeSH in subject analysis as do indexers for journal article literature.

Catalogers use the most specific MeSH terms available to describe the subject content of an item. (See also Specific Headings vs. Broader Headings below.) A very general work may sometimes be described with a single MeSH term. Complex concepts are represented by pre-coordinated main headings when available. When an appropriate pre-coordinated term is not available in the MeSH vocabulary, the concept is represented by the coordination of two or more main headings, or by main heading and topical subheading combinations.

For example, a work on research in occupational therapy is represented by the two main headings OCCUPATIONAL THERAPY and RESEARCH, whereas research in nursing is represented by the pre-coordinated heading NURSING RESEARCH. A work on a heart-lung transplant is represented by the pre-coordinated term HEART-LUNG TRANSPLANTATION whereas a work on transplantation of cartilage is represented the coordination of the main heading CARTILAGE and the topical subheading transplantation.

Cataloging Annotations

Cataloger annotations are provided when more guidance for consistent application of MeSH is needed. Annotations applicable specifically to cataloging are prefaced by the word "CATALOG." Nearly all other MeSH annotations apply equally to cataloging and indexing. Exceptionally, catalogers use disease manifestation concepts such as SIGNS AND SYMPTOMS, EYE MANIFESTATIONS, SKIN MANIFESTATIONS, etc., and a few other very general terms annotated "not used for indexing," which do not have a similar instruction for catalogers.

MeSH Headings

Specific Headings vs. Broader Headings

Catalogers assign the most specific heading or headings available to bring out the main focus of an item. If the work covers several specific topics, the cataloger will assign as many specific subjects from different MeSH trees as required by the content of the work. When more than three specific headings are needed that fall within the same MeSH tree structure, the cataloger assigns the broader heading.

Example: Use EYE DISEASES (C11) if the content deals with
CORNEAL DISEASES (C11.204)
OPTIC NERVE DISEASES (C11.640)
REFRACTIVE ERRORS (C11.744)
RETINAL DISEASES (C11.768)

Headings Not used in Subject Cataloging

There are three types of MeSH headings not used in subject cataloging.

  1. A group of broad, general main headings not used in indexing or cataloging (e.g., FOOD AND BEVERAGES); instead catalogers use the appropriate specific main heading or headings to cover the concepts. These headings are annotated "not used for indexing; CATALOG: do not use" or "not used for indexing or cataloging."
  2. A small group of check tags are not used in cataloging. Check tags are used by indexers on all articles to which they apply, to identify categories of research subjects (e.g., MALE, FEMALE), type of research, or other specific parameters of the subject content of an article. (e.g., IN VITRO). They are identified by the annotation "check tag only." Other similar terms (e.g., ANIMALS, HUMANS, CHILD) may be used either as check tags as indicated above, or as regular MeSH descriptors when they are a focal point of an item being indexed or cataloged. They are annotated "NIM as check tag." These terms are used in cataloging as needed. See also special instructions for Age Group Headings & PREGNANCY below. A small group of Publications Types are used only by indexers. These are annotated: CATALOG: do not use. See also special instructions for Publication Types below.
  3. Corporate names and uniform titles for serial publications, databases, names of laws, etc., found in MeSH, are not used in cataloging. These types of headings are annotated "CATALOG: use NAF entry." Catalogers use the heading from the NLM Name Authority File.

Topical Subheadings

Catalogers, like indexers, use no more than three topical subheadings with any one main heading, except in very rare circumstances. For any item in which more than three subheadings seem to be needed with a single main heading, the cataloger applies the Topical Subheading Hierarchies in an attempt to reduce the number of qualifiers required.

For example, if an item discusses diagnosis, therapy, epidemiology, and mortality of a disease, the disease heading is repeated with each of the first three subheadings. The last subheading is not applied because it falls under epidemiology in the subheading hierarchy.

If an item substantively discusses many aspects of a topic, generally the main heading is used without qualification if the number of topical subheadings cannot be limited to three by applying the subheading hierarchies.

For a topical subheading to be used with a main heading it must be included in the allowable qualifier (AQ) list for that heading. See the Introduction to MeSH section: Qualifiers. The list of Topical Subheadings with Scope Notes and Allowable Categories  provides guidance for qualifying a main heading with a topical subheading by descriptor categories or subcategories. However, some exceptions to the general guidelines apply to specific terms. In the MeSH Browser, the MeSH unit record for each MeSH descriptor includes a complete list of allowable qualifiers valid for use with that descriptor.

Creating traditional subject strings in a local catalog

In NLM's bibliographic files (LocatorPlus and the NLM Catalog) main headings or main heading and topical subheading combinations in bibliographic records are not qualified by geographic terms, publication types (PTs), or language subheadings. Geographic descriptors and PTs are carried in separate fields (MARC 21 fields 651 and 655 respectively in LocatorPlus) and are used in retrieval in coordination with main headings or main heading and topical subheading combinations.

However, in NLM's MARC 21 bibliographic record distribution, subject headings are distributed in a pre-coordinated string, and medical catalogers may construct them in the same manner when they are cataloging at their own institutions. The order of the main headings and subheadings is:

650 _2 $a Main heading $x topical subheading $z geographic $v publication type $x language

Using LocatorPlus records as the source, the $z is taken from the 651 field and appended to each subject heading in a 650 field. The $v field is taken from the 655 field and appended to any subject heading in a 650 field that does not contain a subfield $9 coded "n."

The language subfield, taken from coded data in the 041 field, is only appended to the 650 subject string as subfield $x when one of the following publication types is used in the record: Dictionary, Encyclopedias, Phrases or Terminology.

Age Group Headings & PREGNANCY

Beginning with the implementation of MeSH for 2006, age groups and PREGNANCY are in the same format on distributed records as in NLM's local files. Age groups and PREGNANCY terms are not appended to the subject string on distributed records.

Prior to 2006, when age groups or PREGNANCY were coded as secondary subjects (MARC 21 650 22) they were attached to other specially coded main headings or main heading and topical subheading combinations on records distributed to the licensees on NLM bibliographic data, such as OCLC. NLM catalogers used a local subfield ($9 a) in the subject string in LocatorPlus (MARC 21 650 $9 a) as an instruction to attach age groups to the subject string for distribution.

Examples:

In LocatorPlus prior to 2006:
650 12 $a Concept Formation $x physiology $9 a
650 22 $a Learning $x physiology $9 a
650 22 $a Infant

On distributed records prior to 2006:
650 12 $a Concept Formation $x physiology $x Infant
650 22 $a Learning $x physiology $x Infant

Currently in LocatorPlus as well as on distributed records:
650 12 $a Concept Formation $x physiology
650 22 $a Learning $x physiology
650 22 $a Infant

In LocatorPlus prior to 2006:
650 12 $a Bereavement $9 a
650 22 $a Attitude to Death $9 a
650 22 $a Family Relations
650 22 $a Child

On distributed records prior to 2006:
650 12 $a Bereavement $x Child
650 22 $a Attitude to Death $x Child
650 22 $a Family Relations

Currently in LocatorPlus as well as on distributed records:
650 12 $a Bereavement
650 22 $a Attitude to Death
650 22 $a Family Relations
650 22 $a Child

Publication Types

All MeSH publication types used in cataloging records are entered in MARC 21 field 655, with the second indicator of 2. All MeSH PTs used by cataloging may be appended to the subject string as form subheadings (650 $v) on distributed records. NLM uses 650 $9 n to prevent PTs from attaching inappropriately on distributed records.

Examples:

In LocatorPlus:
650 12 $a Community Mental Health Services
650 22 $a Child $9 n
655 _2 $a Directory

On distributed records:
650 12 $a Community Mental Health Services $v Directory
650 22 $a Child

In LocatorPlus:
650 12 $a Physicians
655 _2 $a Caricatures

On distributed records:
650 12 $a Physicians $v Caricatures

Note: All publication types in the MeSH vocabulary may be used by catalogers unless they are annotated "CATALOG: do not use" or "Not used for indexing or cataloging" or there is an annotation restricting usage such as "CATALOG: do not use for current materials."

For information on previous changes to the structure and content of NLM subject strings in LocatorPlus and on distributed records see also "Subject Headings in NLM MARC 21 Products" in the NLM Technical Bulletin for 2005 September-October http://www.nlm.nih.gov/pubs/techbull/so05/so05_marc.html