This document discusses periarthritis of the shoulder, also known as frozen shoulder. It begins by defining the condition as an inflammatory disorder of the shoulder joint and surrounding soft tissues. It then describes the three stages of frozen shoulder according to Cyriax: stage 1 involves pain with movement, stage 2 includes increased stiffness, and stage 3 is the recovery stage with gradual return of movement. The document outlines causes such as injury, prolonged immobility, diabetes, and thyroid disorders. Signs, symptoms, diagnosis, and management are explained, including medications, cortisone injections, physical therapy, and possibly surgery if conservative treatment fails.