M61.1: Myositis ossificans progressiva

Myositis ossificans progressiva, also known as M61.1 in the ICD-10 classification, is a rare medical condition where bone tissue begins to form within muscles, tendons, ligaments, and other soft tissues. The abnormal bone growth is often triggered by a minor injury or trauma, such as a bump or bruise. This disease progression, known as "flare-ups", can lead to stiffening and immobility in joints, especially in the neck, shoulders, and hips. Over time, individuals with this condition may lose the ability to fully open their mouth, speak, and even breathe properly. Another common symptom is irregularities in the big toes at an early age, which can aid in early detection. The progression and severity of the symptoms can greatly differ from person to person.