Flexor Tendinitis and Trigger Finger

Tendons are strong connective structures that join muscles to bones. In the inner wrist and palm of the hands a group of tendons called flexor tendons connect the flexor muscles in the forearm to the finger bones. The muscles pull on the tendons which cause the fingers to bend, or flex. The tendons run through a series of rings, or pulleys, that form tunnels along the fingers and thumb. They work similar to a line guided along a fishing rod, with the pulleys holding the tendon close to the bone. These tendons are made up of tissue called collagen and elastin, ensuring that they are both tough and flexible.

Flexor tendons need to glide smoothly and are enclosed by synovium, a thin sheath of smooth tissue that allows for easier movement. When the tendons become irritated and inflamed, their ability to glide within these compartments is restricted. This causes wrist and hand pain during movement and tenderness when direct pressure is applied. When the flexor tendons are inflamed it is referred to as flexor tendinitis, also spelled tendonitis.

Tendinitis usually begins with tiny tears in the tendon fibers which can tear apart in much the same way a rope becomes frayed. Once a tendon becomes frayed, an inflammatory response is triggered; over time an inflamed tendon can become thick, bumpy and irregular making it more difficult to glide during hand movements. Without proper rest and time to heal, a damaged tendon can become permanently weakened.

Trigger Finger

Flexor tendinitis is also referred to as "Trigger Finger". Often when tendinitis occurs in one of the flexor tendons it causes the tendon to swell creating a nodule. This nodule becomes too large to easily move through the pulley that holds the tendon to the bone. When you flex your finger, the tendon tries to move through the pulley but the nodule catches at the front of the joint causing the finger to stick at the base of the finger.