Brilliant Commercial Spokesperson Of The Day Dept

Arthritis, n.: acute or chronic inflammation of a joint, often accompanied by pain and structural changes and having diverse causes, as infection, crystal deposition, or injury. (From Greek arthro-, joint + -itis, inflammation.)

Voice-over of woman in arthritis medicine commercial this morning:

"I knew rheumatoid arthritis was painful, but [with outraged astonishment] I didn't know it could attack my joints!"

(Definition courtesy of dictionary.com.)