my granddaughter, B, had just been diagnosed with Pauciarticular Juvenile Rheumatoid Arthritis.

the paciarticular part means pauci-(few) articluar (joints)
pauci (as in paucity) has also has other meanings--like poor (with few worldly good)--pauper.

paucity is not a common word (yet not a rare one either!) and its related words --are interesting..

http://www.bartleby.com/61/roots/IE377.html

my other obsession