Medical Subject Headings (MeSH) is a very comprehensive vocabulary to index the biomedical literature on Medline or PubMed (which is the major Biomedical literature database). MeSH is arranged into Descriptor > Concept > term hierarchy, but I still do not understand the difference between a MeSH descriptor and a MeSH concept.
For example, for Knee
Even after reading the description here and here, I am still not sure about the purpose of MeSH concept and MeSH descriptor.
Could anyone please shed some light on it?