Rural and Urban

I was doing a search for Rural Emergency Departments the other day, and came across a quirk in Ovid Medline:

If you type in:rural, it maps to the following MeSH:

• Rural Health
• Rural Population

However, if you type rural into PubMed's MeSH database or EBSCO's MeSH thesaurus (relevancy ranked), you get:

• Rural Health
• Rural Population
• Rural Health Services
• Hospitals, Rural

None of these are broader/narrower terms of each other.

BTW, if you use EBSCO's MeSH thesaurus with Term Contains instead of Relevancy Ranked, you will get only 2 MeSH:

• Rural Health Services
• Rural Population

Depending on the question, you may or may not want to use all of these, but it's good to know they exist!

Similar quirks appear in Ovid Medline when searching urban