The 2021 MeSH (Medical Subject Headings) vocabulary was evaluated for inclusion in the Classification index. Several additions and changes were made to the Index and Schedules based on this review. All main index headings are now linked to the 2021 vocabulary in the MeSH Browser. Additional minor updates were made to the Index and Schedules.

Summary Statistics for the 2021 Winter Edition

• 51 index main headings added (46 from 2021 MeSH)
• 48 index entries modified
• 1 index heading deleted
• 28 class numbers added Class Numbers Added and Canceled (Current Edition)
• 23 class number captions or notes modified
• 1 class number canceled

For more information about the scope of the 2021 winter edition, see  https://classification.nlm.nih.gov/scope

The 2021 summer version will be published in late August 2021. It will encompass the systematic review of WU (Dentistry. Oral Surgery) and WV (Otolaryngology) schedules.

The PDF version of the NLM Classification was discontinued with the 2019 edition due to low usage.

Contact NLM if you have questions or comments.

Last Reviewed: February 12, 2021