# MeSH — Medical Subject Headings
## Overview
MeSH is the controlled vocabulary thesaurus produced and maintained by the US National Library of Medicine (NLM) for indexing, cataloguing, and searching biomedical and health-related literature. Established in 1960, MeSH is the indexing system for PubMed and provides a hierarchically organised vocabulary of approximately 30,000 descriptors as of 2024, covering diseases, anatomy, organisms, drugs, chemicals, biological processes, and research methodology.
## Structure
MeSH is organised into Descriptor Records (main concepts) and Supplementary Concept Records (chemicals, drugs, rare diseases). Descriptors are arranged in a polyhierarchical tree with 16 top-level categories. The most relevant to neuroscience are: C (Diseases), covering neurological diseases and psychiatric disorders; A (Anatomy), covering brain structures and nervous system anatomy; D (Chemicals and Drugs); G (Phenomena and Processes); and F (Psychiatry and Psychology).
## Relationship to Other Disease Terminologies
MeSH, [[ICD-10]], [[SNOMED CT]], and [[MONDO]] serve different purposes but overlap:
| Terminology | Primary use | Granularity |
|---|---|---|
| MeSH | Literature indexing (PubMed) | Moderate; optimised for search |
| [[ICD-10]] | Clinical billing / epidemiology | High; codeable diagnoses |
| [[SNOMED CT]] | Clinical records / EHR | Very high; post-coordinated |
| [[MONDO]] | Cross-database harmonisation | High; maps all others |
| [[HPO]] | Phenotype description | Very high; symptom-level |
## Connections
- relatedTo: [[SNOMED CT]], [[ICD-10]], [[MONDO]], [[HPO]]
## Resources
- https://www.nlm.nih.gov/mesh/ (MeSH homepage)
- https://meshb.nlm.nih.gov (MeSH Browser)
- https://pubmed.ncbi.nlm.nih.gov (PubMed — primary MeSH-indexed literature database)