A jammed finger is a term used to describe a variety of injuries to the joints of the fingers, resulting from axial loading beyond that which the ligaments can withstand. The injury occurs when the tip of the finger is compressed towards the hand, causing the joint to become compressed. The severity of the damage to the finger increases with the magnitude of the force exerted by the external object on the fingertip. Common parts of the finger susceptible to this type of injury are ligaments, joints, and bones. Toes may become jammed as well, with similar results.

Symptoms of a jammed finger include swelling, reduction of flexibility of joints, pain, and tenderness. There may also be discoloration of the skin due to bruising. These symptoms may persist for up to eight weeks.

Jammed fingers can occur when a force is applied in the direction of the length of the finger from the fingertip (axial loading). Therefore, any recreational activity in which the fingers are held in an outstretched position has the possibility of resulting in a jammed finger. This type of injury is particularly common in ball-related sports, where an incorrect catching method may lead to the ball making contact with the tip of the finger.

A variation of the jammed finger where the extensor tendons on the back of the fingers are damaged is known as mallet finger. Mallet fingers are caused by the same finger trauma as jammed fingers, and are characterized by a difficulty extending the finger.

Most jammed fingers heal within one to two weeks. However, some injuries can result in permanent problems if they are left undiagnosed or untreated. If the injury is severe, it may require medical treatment. Treatment for a jammed finger may include a splint and/or buddy strapping to the neighboring normal finger. In some cases, surgery may be required.