Trigger finger

Trigger finger is a painful condition in which a finger or thumb clicks or locks as it is bent towards the palm.

Thickening of the mouth of a tendon tunnel leads to roughness of the tendon surface, and the tendon then catches in the tunnel mouth. People with insulin-dependent diabetes are especially prone to triggering, but most trigger digits occur in people without diabetes. Triggering occasionally appears to start after an injury such as a knock on the hand. There is little evidence that it is caused by work activities, but the pain can certainly be aggravated by hand use at work, at home, in the garden or at sport. Triggering is sometimes due to tendon nodules in people known to have rheumatoid arthritis. It is not caused by osteoarthritis.