(See also Overview of Hand Disorders.)
The cause of trigger finger is unknown. Trigger finger is common among people with rheumatoid arthritis or diabetes. Repetitive use of the hands (as may occur from using heavy gardening shears) makes trigger finger more likely to develop.
In trigger finger, a finger becomes locked in a bent position. The finger locks when one of the tendons that flex the finger becomes inflamed and swollen, often with a noticeable round, raised area (nodule) in the palm. The inflammation and swelling may cause pain in the palm and in the base of the finger, especially when the finger is flexed and extended.
Normally, the tendon moves smoothly in and out of its surrounding sheath as the finger straightens and bends. In trigger finger, the inflamed tendon can move out of the sheath as the finger bends. However, when the tendon is very swollen, it cannot easily move back in as the finger tries to straighten, and therefore the finger locks. To straighten the finger, a person must pull on the finger to force the swollen area into the sheath—causing a sudden release and popping sensation similar to that felt when pulling a trigger.
A doctor makes the diagnosis of trigger finger by examining the hand and finger.
In people with trigger finger, splinting, moist heat, and nonsteroidal anti-inflammatory drugs (NSAIDs) can help people who have swelling and pain.
Sometimes a corticosteroid and a local anesthetic are injected into the tendon sheath and, along with splinting, may provide safe and temporary but rapid relief of pain and triggering.
Surgery is commonly needed to treat chronic trigger finger.