Trigger finger, medically known as stenosis tenosynovitis, sometimes referred to as trigger thumb as well, is a rather painful condition that can limit and make everyday activities difficult to perform. Whether from the discomfort or the lack of motoric abilities, trigger finger may cause an individual to feel self-conscious and experience hardships in his day to day tasks. But, what causes this condition?

Causes of trigger finger

Causes of this condition are still quite unclear, but there are a few causes proposed by the professionals. Trigger finger is caused by the inflammation (tenosynovitis) and the restriction of the deep and superficial tendons. However, an inflammation is not the only cause of the trigger thumb (or trigger finger), as other factors may also contribute to the occurrence of the condition.

One of such factors may be chronic and repetitive activities that require using the affected finger. Such activities may be simple work tasks such as prolonged computer use or handling of the materials, or everyday recreational activities, for example, knitting, racket sports such as tennis and squash, golf, or other sports that put a lot of action to the wrists and fingers.

Professionals who have mostly suffered from trigger finger are carpenters who use hammers a lot, as well as woodworkers who grip wood or other materials when they cut them, as they are most likely to use their hands as a clamp to hold the materials in place.

Most of the trigger finger cases, however, happen to completely healthy individuals with no apparent reason at all. It has been reported that more than two in 100 people develop some form of trigger finger at some point in their lives, especially when they are over 40 years of age.

Causes of primary and secondary stenosis tenosynovitis

Firstly, there are two types of trigger finger (stenotic tenosynovitis): primary and secondary. Primary stenotic tenosynovitis can be idiopathic and occur among women of middle age. It also occurs more frequently among women than men, however, it can happen during infancy as well.

Secondary stenosis tenosynovitis that can lead to trigger finger can occur due to a disease or other factors such as rheumatoid arthritis, diabetes, gout, amyloidosis, carpal tunnel syndrome, during a dialysis period, and lupus and other factors may be a direct trauma to the affected site, a congenital disorder, and it can also evolve during the postpartum period.

Inflammation and swelling of the tendon

The most common cause of trigger finger is the inflammation of the tendon or the tendon sheath, which is basically a tendon cover. A tendon is a tissue that attaches the bone to the muscle, and in the case of trigger finger, the muscle pulls on the tendon and flexes the affected finger towards the palm.

When the tendon slides out of the tendon sheath due to trigger finger, it cannot slide back in because of the swelling, which causes the finger to remain flexed until a person pulls it straight with the help of the other hand.

Prolonged periods of irritation to the tendon and tendon sheath can result in scarring, a formation of nodules (bumps), and the thickening of the tissue, which makes the condition harder to treat.

Risk factors

There are several factors that may put one at risk of developing the trigger finger syndrome.

• A first risk factor is the gender of the person. Trigger finger syndrome is more common in women than men
• Health issues. Suffering from certain diseases and conditions may raise the risk of getting trigger finger. Such diseases may include diabetes and rheumatoid arthritis, and, as previously mentioned, gout, and carpal tunnel syndrome.
• Prolonged gripping and flexing of the hand. Jobs and hobbies that include prolonged or repetitive use of a hand and fingers and that require gripping and holding objects for a long time can increase the risk of trigger thumb. Such occupations and hobbies can include a lot of handiwork and handicrafts, such as knitting, jewelry making, carpenter jobs and hobbies, and prolonged computer use.