Tendonitis is a term often used to describe an inflamed and painful tendon. Tendons are strong bands or cords of tissue that attach muscle to bone. They help move the bones and joints when the muscles contract.
Some tendons are covered by a protective sheath. The sheath is lined with a membrane that contains synovial fluid, which helps the tendon to move easily and minimises friction. Tendon pain can be caused by small tears in the surrounding tissue, or the gradual deterioration of a tendon where it connects to the bone. This type of tendon pain is often known as tendinopathy.
Tendon pain can affect tendons in the:
- back of the heel
What causes tendonitis?
Tendonitis is commonly caused by:
- a tendon injury – for example, while playing sports that involve throwing or using a racquet, such as tennis
- overusing a tendon – for example, using a computer mouse may cause tendonitis in your wrist because of repetitive strain injury (RSI)
Tendonitis tends to be more common in people with diabetes. The reasons for this are not fully understood.
Tenosynovitis (inflammation of the sheath that surrounds the tendon) is sometimes associated with rheumatoid arthritis.