When the tendon can't move smoothly inside the sheath, a trigger finger may develop. The finger gets stuck in a flexed or bent position. When it is straightened out, the finger pops back like a trigger on a gun.

Any finger can be affected. Usually the thumb, middle, or ring fingers are involved. In most cases, the etiology (cause) is unknown. This is referred to as idiopathic.

Sometimes a specific etiology can be identified. This could be a soft tissue or bone tumor, arthritis, bone spur, or scar tissue from a previous injury. Trauma as a cause is possible if damage to the tendon results in scarring or the formation of a fibrous nodule.

There is medical treatment available for trigger finger. Steroid injection, hand therapy, and sometimes, surgery can be helpful. See a hand surgeon or orthopedic surgeon if symptoms persist or cause decreased function.