Sources

http://www.mayoclinic.org/diseases-conditions/arthritis/basics/definition/con-20034095

http://www.mayoclinic.org/diseases-conditions/arthritis/basics/definition/con-20034095

http://www.chiropractor-brighton.co.uk/morten-westergaard/live-well-with-arthritis/

http://www.webmd.com/osteoarthritis/guide/options-basics

http://www.medicalnewstoday.com/articles/7621.php#what_causes_arthritis