MeSH Tree Structure
Overview
Main headings are organized in a "tree" with 16 main branches:
- A. Anatomy
- B. Organisms
- C. Diseases
- D. Chemicals and Drugs
- E. Analytical, Diagnostic and Therapeutic Techniques and Equipment
- F. Psychiatry and Psychology
- G. Phenomena and Processes
- H. Disciplines and Occupations
- I. Anthropology, Education, Sociology and Social Phenomena
- J. Technology, Industry, Agriculture
- K. Humanities
- L. Information Science
- M. Named Groups
- N. Health Care
- V. Publication Characteristics
- Z. Geographicals
Each branch has many levels of sub-branches, and each heading has a position in the hierarchy. For example:
Anatomy Body Regions Torso Back Lumbosacral Region
Sacrococcygeal Region
Some terms appear in more than one branch of the tree. For example:
Anatomy Body Regions Head Ear Anatomy Sense Organs Ear Ear, External +
Ear, Middle +
Ear, Inner +