The fingers most often affected are the ring finger and the thumb, but the condition can affect any finger. Trigger finger happens when the tendon that controls that finger can't glide smoothly in the sheath that surrounds it.

The exact cause of trigger finger is unknown, however it is associated with repetitive gripping or squeezing hand motions as well as with certain medical conditions (comorbidities), including diabetes, rheumatoid arthritis, gout, pseudogout, sarcoidosis and hypothyroidism.

Trigger finger, or stenosing tenosynovitis, is tenosynovitis of the flexor sheaths that typically occurs in the 4th finger and thumb as a result of repetitive use. It is a common condition that can cause significant functional impairment.

Trigger finger is a condition affecting tendons that flex the fingers and thumb, typically resulting in a sensation of locking or catching when you bend and straighten your digits. Other symptoms may include pain and stiffness in the fingers and thumb. The condition is also known as stenosing tenosynovitis.