<prompt> Riders bones are ossification ofAdductor brevisAdductor longusAdductor magnusFlexor digitorum superficialis  <response>: Riders bone develops in the tendon of adductor longus in professional riders. It is a sesamoid bone.that has no periosteum and ossifies after bih. Reference: BD Chaurasias handbook of general anatomy, 5th edition, pg 55 