This common condition, also known as stenosing tenosynovitis, is a narrowing of a portion of the tendon sheath in the finger or thumb that interferes with normal finger movement. This condition most commonly affects the ring finger, but can affect any digit. It is more common in middle-aged women, but anyone can be affected, even newborns.
This condition may be caused by overuse or repetitive use of the hand. Normally, as a finger is bent and extended, the finger’s flexor tendons glide smoothly through a series of fibrous tunnels in the finger and hand. Trigger digit results from a narrowing of the fibrous tunnel in the palm called the first annular (or A1) pulley.