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What Causes Trigger Finger?

Have you ever had a finger or fingers get stuck in a bent position? If so, you may have trigger finger. It may be accompanied by pain, swelling, and a clicking sensation in the finger. Once stuck, your finger may just snap back into a straight position on its own like a trigger has been pulled and released.

What is trigger finger?

Trigger finger is also known as stenosing tenosynovitis and occurs in about 2-3% of the population. It causes swelling inside the finger and narrows the space around the tendon. This swelling can cause your finger to get locked in a bent position.  

Understanding the causes of trigger finger

To understand what causes trigger finger, let’s explore how the structures inside your fingers and forearm work. You have several long, cord-like flexor tendons that attach the muscles of your forearm to the bones of your fingers.

When the muscles in your forearm contract, the flexor tendons bend your fingers. The tendons pass through a tunnel in the palm of your hand and fingers. This tunnel, known as the “tendon sheath,” helps the tendon to glide smoothly when the fingers bend and straighten.

The tendon sheaths have bands of tissues called “pulleys” that hold the flexor tendons close to the bones of your fingers. The tendons normally move easily through these pulleys as the fingers move.

When you have trigger finger, this pulley becomes inflamed and thick, which makes it hard for the flexor tendon to glide easily through the pulley as the finger bends. The flexor tendon may become swollen, and you’ll have a small bump on the palm of your hand at the base of the affected finger.

When you flex the affected finger, this nodule passes through the pulley, causing a catching or popping feeling. This commonly causes pain in the finger. Severe trigger finger can cause the finger to lock in a bent position. You may even have to use your other hand to straighten the finger.

All of this swelling and lack of movement is the underlying cause of trigger finger.

Symptoms of trigger finger

Symptoms of trigger finger range from mild to severe, and commonly start as a painless click when the finger is moved. Trigger finger can happen in any of your fingers, including your thumb. It may affect just one hand or both.

Triggering of the affected finger is usually worse when you grasp an object or when straightening your finger.

You may have all or some of the following symptoms:

Risk factors for trigger finger

Doctors don’t know exactly what causes trigger finger, but we do know a few things that will increase your risk of developing it. They include:

Other health conditions

If you have any of the following medical issues, you’re at a higher risk of trigger finger: diabetes, rheumatoid arthritis, carpal tunnel syndrome, de Quervain’s disease, hypothyroidism, renal disease, and amyloidosis.

Repeated gripping

If you have a job or hobby that involves repeated hand use and gripping, you may be at a greater risk of developing trigger finger.

Carpal tunnel syndrome surgery

If you’ve had surgery for carpal tunnel syndrome in the past six months, you may be at an increased risk for trigger finger. It can develop as a complication of the surgery.

Trigger finger is also more common in women and in people in their 50s and 60s.

If you’re suffering from symptoms of trigger finger, our trained hand and upper extremity surgeons at Atlantic Orthopaedic Specialists can help. We specialize in treating a wide range of disorders and injuries of the hands. Contact us to set up an appointment.

Brad Carofino, MD Dr. Brad Carofino is a board-certified (American Board of Orthopaedic Surgery), fellowship-trained orthopaedic surgeon who specializes in shoulder & upper extremity surgery. Dr. Carofino is an expert in shoulder replacement surgery, minimally invasive arthroscopic rotator cuff repair, and complex reconstructive procedures of the upper extremity.

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