This affection, which is generally known by the title trigger finger, is also called variously digitus recellens or lock or snapping finger and sometimes spasm of the finger1. The original title given to it by Notta and Nélaton was "doigt à ressort" (spring finger), and in Germany it is called "schnellender" or "federnen finger" (snapping or spring finger). It is nearly always met with in flexion (Fig. 1), and particularly in flexion sufficiently great to allow the tip of the finger to rest or to press firmly on the palm of the hand. When the trigger action is present the finger can only be extended by a considerable muscular effort, or by the aid of the other hand.
In overcoming the hitch by the action of the extensor muscles the finger springs back suddenly and usually with more or less pain, though when arrested or replaced by the sound
WEIR RF. TRIGGER FINGER.. JAMA. 1907;XLIX(14):1168-1173. doi:10.1001/jama.1907.25320140014001d