Adhesive capsulitis, also known as frozen shoulder, is a condition characterized by inflammation and stiffness of the shoulder capsule that greatly restricts motion and causes pain. It typically affects individuals aged 40-60 and more commonly affects females. Movement is severely limited, especially external rotation, and pain is often worse at night. While the exact cause is unknown, it is usually self-limiting and resolves over 18 months with conservative treatments like physiotherapy, corticosteroid injections, and manipulation under anesthesia. Surgery is rarely required.