Trigger finger is a condition where the baby's finger does not move smoothly or is "stuck", in more severe cases it cannot be extended at all, always curled in a position like the image of a "trigger".

Trigger finger is a condition caused by inflammation of the annular ligament that fixes the flexor tendons of the fingers. The inflammation progresses to cause pain when flexing and extending the fingers, and movement is interrupted by a “pop” at a certain location of the finger, usually at the middle joint (proximal interphalangeal joint).