Trigger Finger
Trigger Finger picture album Several pictures illustrating the anatomy and treatment of a trigger finger. Trigger Finger video 3D animation demonstrating the anatomy of a trigger finger. Trigger Finger Release video 3D animation demonstrating a common surgical procedure used to treat trigger fingers.
Trigger finger is a condition in which a finger locks up, or gets stuck, in a flexed position.  It can be difficult and painful to straighten out the finger.  When it does straighten out, it snaps open, or triggers.  In order to understand why this occurs, it is important to understand a little bit about the anatomy of the finger. Two tendons travel up the bones of the fingers.  The flexor digitorum profundus attaches to the bone at the tip of the finger, known as the distal phalanx.  The flexor digitorum superficialis, which sits just on top, attaches to the middle phalanx.  As muscles in the forearm contract, they pull on these tendons which in turn pull on the bones of the finger.  This bends, or flexes, the finger.  Without anything holding the tendons up against the bones, they would bowstring as the muscles contracted.  And so there are small, ligamentous structures known as pulleys that hold the flexor tendons in place as they travel down the bones of the fingers.  Some of the pulleys have fibers that cross over one another.  They are called cruciate pulleys.  Some of the pulleys simply pass straight over the tendons.  They are called annular pulleys.  The pulleys are numbered according to their position. Triggering usually occurs at the A1 pulley, or the first annular pulley.  If something irritates the flexor tendons, they may swell.  This causes rubbing and friction against the pulley each time the finger bends and extends.  The irritation worsens and the tendons thicken.  Over time, the tendons become too thick and swollen to glide normally through the pulley.  Once the finger has been flexed, the thickened, swollen portion of the pulley gets stuck.  With effort, it can be forced through the pulley and the finger triggers open. Trigger Finger Release Trigger finger, also known as stenosing tenosynovitis, is a condition in which the flexor tendons of the finger become too thick and swollen to fit through the A1 pulley.  The finger locks up in a flexed position.  With effort, the tendon can be pulled through the pulley and the finger triggers open. Treatment options for trigger finger include conservative measures such as bracing, anti-inflammatory medications, and steroid injections.  However, nonsurgical treatment is often ineffective. Surgical treatment for a trigger finger is known as a trigger finger release.  It is a relatively simple and safe procedure.  Anesthesia is provided to numb the hand.  A small incision is made over the A1 pulley.  The pulley is then identified and cut.  The finger is flexed and extended to ensure that locking and triggering is no longer present.  The skin is then closed with sutures and a soft dressing is applied. There are other pulleys present to stabilize the flexor tendons, and so cutting the A1 pulley does not adversely affect the function of the hand or finger. Sutures are generally removed in about 1 week.  Care must be taken not to do anything strenuous with the hand for a few more weeks to allow the incision to heal.