<prompt> A most common cause of tarsal tunnel syndrome -OsteoarthritisAnkylosing spondylitisPsoriatic arthritisRheumatoid arthritis  <response>: Amongst the given options, RA is the most common cause of tarsal tunnel syndrome.Facts about etiology of tarsal tunnel syndromeMost common origin of tarsal tunnel syndrome is idiopathic 21-36.When the cause is known, trauma is the most common cause.Two most common systemic causes of tarsal tunnel syndrome are diabetes m.c. and RA 2nd m.c. 