This problem can happen in a finger or a thumb. In a finger, the middle joint is bent back and the joint at the fingertip is bent down. In a thumb, the joint at the thumb's base is bent back and the joint at the thumb's tip is bent down.
How does it happen? It’s commonly linked to rheumatoid arthritis, which damages joints and tissues in the fingers. It also may result from other joint diseases, or when a ligament below a finger’s middle joint stretches or tears.
What are the symptoms? First is the way it looks. Some say the finger looks like a swan's neck from the side. It also may feel stiff. And when you try to bend it, you may feel a snapping sensation as the tendons flex. This can be painful. As your condition progresses, you may lose your ability to bend it.
How do we treat it? It depends on the severity. If it's minor, you may not need treatment. You may benefit from a splint or a special ring that you wear to keep your finger or thumb in the correct position. For a severe swan neck deformity, you may need surgery. Your doctor will create a plan that's right for you.