The movement of our fingers is helped by ligaments that move the bones according to muscle function. Its flexors run through a passage, the tendon sheath, from the forearm muscles to the fingers. The inner surface of the tendon sheath is slippery, allowing the tendons to slip.
A trigger finger develops if a thickening or lump is formed on a short section of the tendon, or if inflammatory deposits or thickening occur on the inner surface of the pulleys.
When the finger is moved, this thickened tendon should slide through the narrowed section of the passage, causing a snapping, crackling sensation in the finger and a distinctive sound.
When tendon movement becomes difficult or gets stuck, it causes further inflammation and swelling, leading to an increase in complaints as a pathological cycle. Sometimes the finger gets stuck permanently, in which case it locks in a folded or extended position.
The reasons for its formation are not clear, it can be caused by overloading the hand, monotonous, constant movements, mild injury of the palm, which irritates the flexor tendons, scarring and also predisposing to certain diseases (diabetes, arthritis).