Diagnostic criteria: 1. clear history of trauma or surgery; 2. local pain, stiffness, contracture, deformity and functional limitation of the affected joint; 3. irregular cloudy or cotton wool-like ring-shaped faint shadow in the soft tissue with smooth edges and bone density shadow with trabecular structure on X-ray; CT examination of the lesion is mainly characterized by slender punctate calcification, mass-like calcification and plaque calcification with off-center distribution and a High-density “eggshell-like” calcified ossification ring at the edge. The center is a low-density area; 4. Pathological examination shows a typical three-band distribution: the center is a hemorrhagic area with phagocytes, mesenchymal cells and iron-containing hemoglobin. The middle zone is the atrophic muscle fiber zone, dominated by fibroblasts. The outer zone is the ossification zone, mainly fibroblasts, osteoblasts and osteocytes. Differential diagnosis: 1. In the early stage, osteomyositis needs to be differentiated from soft tissue tumors such as synovial sarcoma and smooth muscle sarcoma; 2. In the middle stage, osteomyositis needs to be differentiated from chondrosarcoma, paracortical osteosarcoma and liposarcoma with calcification or ossification; 3. In the late stage, if the lesion is close to bone, it needs to be differentiated from paracortical osteosarcoma. The difference between progressive and restrictive myositis ossificans is a hereditary connective tissue disease, with lesions located in the muscles of the trunk, muscle cavities, fascia and ligaments, and even involving the transverse muscles of the body, and clinically combined with congenital bunion (toe) deformity, while restrictive myositis ossificans The only manifestations are mass-like calcifications in the soft tissues. Pathological examination remains the gold standard for the diagnosis of these diseases.