[dba-SQLServer] Where are foreign key constraints?

I built a database diagram where i dragged and dropped my PKs out onto FKs.  Now I am getting error 
messages like:

The insert statement conflicted with the foreign key constraint...

I look at the constraints folder in each table and there is no FK_ constraints listed.  I assume 
that they are stored somewhere else?  Am I doing something wrong somewhere?

-- 
John W. Colby
www.ColbyConsulting.com