Trigger finger is a condition in which one of your fingers or your thumb catches in a bent position. Your finger or thumb may straighten with a snap – like a trigger being pulled and released. If trigger finger is severe, your finger may become locked in a bent position.
An often painful condition, trigger finger is caused by a narrowing of the sheath that surrounds the tendon in the affected finger. People whose work or hobbies require repetitive gripping actions are most susceptible to this condition. Trigger finger is also more common in women than in men, and in anyone with diabetes.
Treatment of trigger finger, also known as stenosing tenosynovitis, varies depending on the severity of the condition. Treatment ranges from rest to medications to surgery.
Signs And Symptoms
At first, your affected finger may seem stiff and may click when you move it. You may notice a bump (nodule) or tenderness at the base of the affected finger in your palm. This is the spot where the tendon is likely catching.
As trigger finger worsens, your finger may catch at times in a bent position and then suddenly pop straight. Eventually, the finger may not fully straighten. Trigger finger is not the same as Dupuytren’s contracture – a condition that causes thickening and shortening of the connective tissue in the palm of the hand – though it may occur in conjunction with this disorder.
Trigger finger most often affects your thumb or your middle or ring finger. More than one finger may be affected at a time, and both hands might be involved. Triggering is usually more pronounced in the morning, while firmly grasping an object or when straightening your finger.
The cause of trigger finger is a narrowing of the sheath that surrounds the tendon in the affected finger. Tendons are fibrous cords that attach muscle to bone. Each tendon is surrounded by a protective sheath – which in turn is lined with a substance called tenosynovium. The tenosynovium releases lubricating fluid that allows the tendon to glide smoothly within its protective sheath as you bend and straighten your finger – like a cord through a lubricated pipe.
But if the tenosynovium becomes inflamed from repetitive strain injury or overuse or due to inflammatory conditions, such as rheumatoid arthritis, the space within the tendon sheath can become narrow and constricting. The tendon can’t glide through the sheath easily, at times catching the finger in a bent position before popping straight. With each catch, the tendon itself becomes irritated and inflamed, worsening the problem. With prolonged inflammation, scarring and thickening (fibrosis) can occur and bumps (nodules) can form.
Trigger finger generally results from swelling within a tendon sheath, restricting tendon motion. A bump (nodule) also may form.
If you routinely grip an item – such as a power tool or musical instrument – for extended periods of time, you may be more prone to the development of a trigger finger. You’re also at greater risk if you have certain medical conditions, including rheumatoid arthritis, diabetes, hypothyroidism, amyloidosis and certain infections – including tuberculosis and sporotrichosis, a fungal infection that usually affects the skin. Trigger finger is also more common in women than in men.