The spelling of the word "arthragra" can be confusing for many people. The word is pronounced as /ɑrθrəɡrə/, and is used in medical terminology to refer to pain and inflammation in the joints. The spelling of this word is derived from the Greek words "arthro" meaning joint, and "agra" meaning pain. The extra "a" after "gra" is added to make the pronunciation easier by breaking up the "r" sounds. Despite its difficult spelling, "arthragra" is a common term used by medical professionals to describe joint pain.
Articular gout.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.