Tendonitis is a general term used to describe inflammation associated with a tendon. Tendons connect muscles to bone, and inflammation of these rope-like tissues is the most common cause of soft-tissue pain. Tendonitis differs from arthritis, which refers to inflammation of a joint. Common areas for the condition include the shoulder, elbow, wrist, knee, back of the ankle and foot.
The onset of tendonitis can usually be attributed to overuse of the associated area, but can also occur in areas where calcium deposits have developed. As we grow older, repetitive motion can injure the tendon where it attaches to the bone, promoting an inflammatory response by the body. This inflammation can cause “pain on motion,” swelling, warmth, tenderness, and redness. The latter tendonitis symptom is called “erythema” and refers to the dilation of the blood capillaries as part of the inflammatory process.
If tendonitis treatment is not started when your pain and discomfort are relatively mild, complications may develop. These may include: pain that interrupts your sleep, loss of strength or motion in your affected arm, difficulty doing things that require moving your injured arm behind your back or over your head, such as fastening zippers or buttons, or placing objects in high places.