Differentiation of frozen shoulder from impingement of the acromion: primary frozen shoulder; impingement of the acromion. Pathologic basis: idiopathic inflammation, fibrosis, contracture of the joint capsule; impingement of subacromial structures producing congestion and edema, tendonitis, rupture. Nature of pain: significant nocturnal pain; some patients have nocturnal pain. Site of pressure point: rotator cuff space (medially); anterolateral to the acromion. Mobility: active/passive activity restriction presenting global; mild activity restriction; impingement factors excluded Special examination: negative tendon test; positive impingement test; pain arc (60°-120° of abduction) Treatment principles: anti-inflammatory and analgesic based on staged pathological characteristics, improvement of mobility, muscle strength training, avoidance of impingement movements, motor training based on pathological mechanical mechanisms; targeted treatment for damaged tissues The treatment is targeted to the damaged tissue. Treatment methods: physical factors, oral NSAIDS, intra-articular steroid injections, acupuncture, distraction and arthrodesis, training of peri-scapular muscles and rotator cuff muscles, ultrasound physiotherapy (ultrasound, DFM), injections, arthrodesis if the joint movement is limited.