Extensor Tendonitis

Although this website is primarily about muscles (not tendons), it becomes impossible to talk about finger and hand movement without focusing on tendons - specifically the "extensor" and the "flexor" tendon groups. As you know, the fingers and hands are capable of extreme dexterity and fine control. Much of this control stems from muscles in the forearm and wrist which connect directly to long, tough tendons that extend into the reach of the fingers and hand.

Extensor Tendons - What, Where & Why?

Extensor tendons are located at the top of the wrist and the back of the hands and they connect muscles in the forearm to the finger bones. Muscles in the upper forearm pull on the tendons which cause the hand and fingers to extend. 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.

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

Tendon fibers can tear apart in the 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.

An injury to these tendons can will make everyday tasks difficult, and may very well affect a persons performance or abilities at work. At present, the results of tendon repair surgery are far from ideal, as such an invasive technique can often create excess scar tissue (adhesions) between the sheath and the tendon, restricting mobility and leading to a loss of function.