The tendons that bend the fingers and thumb travel through the hand and enter a tunnel just before passing into the digit. 

With the inflammation of arthritis or repetitive movements, the tendon can sometimes get caught at the entrance of the tunnel. This causes  clicking of the finger or, when more severe, locking of the finger in a bent position. Straightening the finger can then be quite painful. Although the clicking appears to be at the middle joint of the digit, the problem is in the palm, and sometimes a tender  nodule can be felt. 

If the condition is a problem for the patient, then we find that a steroid injection around the tendon will give long term relief. 

If triggering recurs or doesn’t fully settle, then a small operative procedure under local anaesthetic provides  a permanent solution.  

It is not uncommon for patients to return at a later date with triggering in a different digit.