A Boutonniere deformity results from a Zone III extensor tendon (central slip) injury, and presents as PIP flexion and DIP hyper-extension. It gets its name from the "button-hole" appearance ("Boutonniere" in French.) It is caused by disruption of the central slip over the PIP joint, which can happen in several ways, such as laceration, closed rupture / traumatic avulsion (jammed finger), or capsular distension (e.g. in rheumatoid arthritis). View the best products for Boutonniere deformity.