Joint manifestation (1)morning stiffness stiffness persisting for over 30 minutes is prominent in the morning or after daytime activity and subsides during the day The persisting length of morning stiffness is associated with the degree of joint nflammation The duration of morning stiffness is used as the index of disease activity1. Joint manifestation （1）morning stiffness – stiffness persisting for over 30 minutes is prominent in the morning or after daytime activity and subsides during the day – The persisting length of morning stiffness is associated with the degree of joint inflammation. – The duration of morning stiffness is used as the index of disease activity