Tenosynovitis (also known as trigger finger) is a painful and uncomfortable condition that affects the tendons in the hand. The thumb, or any finger can be affected. This includes index and ring fingers. The finger becomes locked in one position. It is difficult to straighten or bend the finger when it gets stuck either in a bent or straight position. The finger becomes difficult to move, causing pain, clicking, and loss of movement.

Trigger finger is characterized by inflammation of the flexor tendon or the area surrounding it. This causes the space in the sheath around the tendons to be reduced. It becomes more difficult for the finger to move fully. Tendons are fibrous connective tissue that attaches the muscle to the bone. Tendons also attach muscle to other structures of the body. The tendons in the fingers are responsible for the bending and retraction of the index, middle, and small finger. The tendons are moved by many muscles that are attached to them. These tendons and connective tissues pulleys that hold the tendon to bone of the fingers are where the trigger finger starts. These tendons can develop knots or the sheath that covers the tendons may swell and narrow, preventing the movement. This is a painful condition that causes popping, bursting and pain when you move your finger. The more inflammation there is, the worse the swelling and irritation will be. Trigger finger can be caused by many factors.