<prompt> Riders bone ossify in theAdductor LongusGluteus MaximusLateral head of GastronemiusTibialis Posterior  <response>: In horse riders, the rounded tendon of adductor longus frequently gets calcified as a result of its friction together with the horseback. This calcified tendon is named riders bone.Reference: Chaurasia Volume II; 7th edition; Page no: 41 