Trigger finger, or stenosing tenosynovitis, occurs when the sheath surrounding a flexor tendon in your finger becomes inflamed and thickened. This can interfere with the tendon’s smooth movement, resulting in a catching or locking sensation when bending or straightening the finger. The condition gets its name from the sudden “snap” or release when the finger moves. While it can affect any digit, it most commonly involves the ring finger, middle finger, and thumb (known as trigger thumb).
Primary trigger finger develops without any underlying medical condition and is the most common type. It typically affects adults between 40-60 years old, with women more frequently affected than men. The dominant hand is often involved.