What is a trigger finger

The muscles of your hand perform a number of different movements. But for the most part we notice that they bend and straighten your fingers. You can normally do this thousands of times a day and never notice that not all of these muscles are actually in your hand.

What are you talking about?

Look at your elbow and make a fist. Did you notice that just below your elbow a lot of bulging happens? That's because some of the muscles involved in moving your fingers attach to your elbow and forearm. You may have heard about pain syndromes from these muscles. We've talked about them in past articles. They're often known as tennis elbow and golfer's elbow.

What does that have to do with my finger

Hold your finger just below the furthest crease, and try and bend the tip of that finger. Notice how it bends? If you can't bend that finger tip then you probably tore the tendon that bends that part of your finger. It usually happens during a sports injury. If you also can't get the finger into your hand to make a fist then you have a tear of your flexor digitorum profundis (FDP). 

The muscle bellies of these finger muscles travel down your arm and attach into the bones of your fingers through long tendons. Two of these muscles are involved in bending different parts of your fingers. You can see them in action by performing two simple tests.

Now try and bend that same tip of your finger while not allowing any of your other fingers to bend. Not as easy to do? That's because preventing your other fingers tips from moving prevents you from contracting FDP. The only muscle that can still bend your finger is flexor digitorum superficialis (FDS) and it can't bend that last knuckle.

These two tendons run in a tunnel, or sheath, on the palm of your fingers. Generally there's enough room for the tendons and your hand functions without you noticing anything

Then why is my finger clicking?

Sometimes problems happen with these tendons. Scar tissue of the tunnel, or swollen tendons can cause the tendons to get stuck. This most commonly happens when the finger is bent and you try and straighten it. Trigger finger affects 2-3% of the population but can be as high as 20% in diabetics.

In its early stages your finger will straighten with a little bit of extra muscular effort and will often release with a snap or a click. Some people find it funny and demonstrate it as a party trick. But if it continues to progress you may be unable to straighten your finger without using your other hand to help.

What can I do about it

The first step is to stop trying to make it click. Continuing to trigger it can further inflame the tendons and can make it worse. If you've been repetitively gripping with your hand try and reduce it to reduce the swelling of your tendons. Repetitive chopping and gripping tasks such as when you're cooking or gardening are the usual culprits.

Conservative management techniques including manual therapy, ultrasound and shockwave have been shown to be effective in reducing the frequency of clicking, improving function and reducing the risk of recurrence. If the trigger is too severe then a cortisone injection becomes the next option to reduce the swelling and free your finger.

References

Johnson, E. “Recognizing and treating trigger finger” Journal of Family Practice September 2021

Salim, N. et al “Outcome of corticosteroid injection versus physiotherapy in the treatment of mild trigger fingers” Journal of Hand Surgery 27(1) 2011