Trigger finger affects the flexor tendons in the palm of your hand. They're responsible for making your fingers and thumbs open and close.
Flexor tendons are tough, string-like structures that attach bones in finger joints at one end and forearm muscles at the other. They're enclosed in a fluid-filled sheath which help the tendons to glide smoothly. These sheaths are attached to the inside of finger and thumb joints with small loops or pullies.
When the muscle contracts it pulls the tendon and the joint moves.
In trigger finger, the tendon becomes inflamed or thickened and can’t pass easily through the sheath. This makes it hard to move the affected finger or thumb.
Sometimes the tendon bunches into a small, lumpy knot.
It most often affects the thumb, ring finger or little finger of either – or both – hands. You’re more likely to get it in the hand you use most.
Trigger finger symptoms include:
Your doctor will discuss your symptoms with you and examine your hand for:
It's not known exactly what causes trigger finger, but it’s more common:
It can often be caused if you put prolonged pressure on the palm of your hand, such as using a screwdriver.
In some cases, trigger finger doesn't need treatment and will get better by itself.
However, if it doesn’t improve, treatment is needed otherwise the finger or thumb may become permanently bent.
Treatment options include: