(Digital Flexor Tendinitis or Digital Flexor Tenosynovitis)
Trigger finger is locking of a finger in a bent position caused by inflammation of a tendon in the finger.
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 nodule in the palm. 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 straightens, and therefore the finger locks. To straighten the finger, a person must force the swollen area into the sheath—causing a popping sensation similar to that felt when pulling a trigger.
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.
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.