Trigger finger is a condition where there is a size disparity between the flexor tendons and the surrounding pulley system at the first annular pulley (the A1 pulley). This causes the tendon to catch on the pulley as it attempts to glide through unless enough pressure is developed to allow it to forcefully move through the pulley. The exact cause of trigger finger is not always clear, but it is often attributed to overuse injuries or repetitive motions.