Jammed finger: Lay terminology that refers to an injury of the finger joints. The most common joint affected is the proximal interphalangeal joint (PIP), the joint formed by the first and second finger bones. A jammed finger occurs because of an on-end injury to the tip of a finger. The injury most commonly occurs during athletic activity, particularly with ball-handling sports.
The term is not medically precise, and a variety of injuries to the finger may actually occur when the finger is "jammed," including tendon or ligament damage, as well as fracture or dislocation of the bones. This type of injury may be very painful. Treatment and outcome depend upon the severity and type of injury.