Trigger finger happens when tendons in the finger or thumb become inflamed. Tendons are tough bands of tissue that connect muscles and bones. Together, the tendons and muscles in the hands and arms bend and straighten the fingers and thumbs.
A tendon usually glides easily through the tissue that covers it (called a sheath) because of a lubricating membrane surrounding the joint called the synovium. Sometimes a tendon may become inflamed and swollen. When this happens, bending the finger or thumb can pull the inflamed tendon through a narrowed tendon sheath, making it snap or pop.
What Causes Trigger Finger?
Trigger finger can be caused by a repeated movement or forceful use of the finger or thumb. Rheumatoid arthritis, gout, and diabetes also can cause trigger finger. So can grasping something, such as a power tool, with a firm grip for a long time.
Who Gets Trigger Finger?
Farmers, industrial workers, and musicians often get trigger finger since they repeat finger and thumb movements a lot. Even smokers can get trigger thumb from repeated use of a lighter, for example. Trigger finger is more common in women than men and tends to happen most often in people who are 40 to 60 years old.