Patients often feel stiffness and pain in joints, limbs, lumbar and other affected areas when they wake up in the morning, when they start to move, or when they change to another posture after being in a certain posture for a long time. PMR is a clinical syndrome characterized by pain in the proximal muscles of the extremities and trunk, and is sensitive to low-dose hormone therapy. It often manifests as pain and stiffness in 2 or more of the neck, scapular girdle and pelvic girdle muscles, lasting 30 minutes or longer, for not less than 1 month, in people older than 50 years. Rheumatoid arthritis Rheumatoid arthritis (RA) is a chronic, inflammatory synovitis-based systemic disease of unknown etiology. It is characterized by polyarticular, symmetric, aggressive joint inflammation of the small joints of the hands and feet, often accompanied by extra-articular organ involvement and positive serum rheumatoid factor, which can lead to joint deformity and loss of function. 3, myotonic syndrome Myotonic syndrome (myotonic syndrome) is a group of rare genetic diseases, including congenital myotonic, atrophic ankylosis, congenital paramyotonic ankylosis and other diseases. The common feature is that the tonic contraction of the muscle cannot be immediately relaxed after active contraction of the random muscle, or after the administration of various mechanical or electrical stimuli. Tonic contraction of the muscle is stiff, but not accompanied by pain. Cold, excitement, apprehension, fatigue, and fever can aggravate the muscle tonicity. Muscle balls may appear when the muscle is tapped with a percussion hammer. Tonic potentials may appear on electromyography. 4. Radial trunk fracture Radial trunk fracture alone accounts for only 12% of all forearm fractures and is predominant in young adults.