Tendons are cords of tough, fibrous connective tissue that attach muscles to bones. Tendinitis is an inflammation of the tendon. The condition may also involve the tendon sheath, usually close to where the tendon joins the muscle. Tendinitis is also informally spelled tendonitis.
Tendons are generally healthy structures that appear glistening white to the naked eye. If you’ve ever carved a turkey, the tendons are the tough bands you cut through to get the drumsticks apart.
The most common cause of tendinitis is overuse and repetitive motion from recreational, athletic, or occupational activities. Risk factors for tendonitis include repetitive movement, trauma, thermal injury to the tendon, use of certain antibiotics (such as levofloxacin andciprofloxacin), and smoking. Tendinitis can also occur in people with diseases such asrheumatoid arthritis, obesity, and diabetes.
Most common types of tendonitis
Medial epicondylitis (golfer’s elbow, baseball elbow, suitcase elbow) is caused by inflammation of the tendons that attach to the medial epicondyle of the elbow. If you put your arms to your side with the palms facing forward, the medial epicondyle is the bony part of the elbow nearest to your body. Repetitive movements involving forceful wrist flexion and rotation can cause this elbow tendinitis.
Lateral epicondylitis (tennis elbow) is caused by inflammation of the tendons that attach to the lateral epicondyle of the elbow. If you put your arms to your side with the palms facing forward, the lateral epicondyle is the bony part of the elbow farthest away from your body. Repetitive movements involving extension and rotation of the wrist can cause this elbow tendinitis.
Rotator cuff tendinitis (swimmer’s shoulder, tennis shoulder, pitcher’s shoulder) is caused by sports that require movement of the arm over the head repeatedly. This repetitive motion causes inflammation on the rotator cuff, a group of muscles that control shoulder rotation. The supraspinatus, infraspinatus, teres minor, and subscapularis tendons form the rotator cuff tendons.
Calcific tendinitis is caused by calcium deposits in the rotator cuff tendons.
Bicipital tendinitis is inflammation of the tendon that attaches the biceps muscle (located in the front of the arm) to the shoulder. Wear and tear over time or overuse are common causes of bicipital tendinitis.
Patellar tendinitis (jumper’s knee) is inflammation of the patellar tendon that attaches the kneecap to the tibia. Patellar tendinitis is caused by repetitive jumping, running, or cutting movements.
Popliteus tendinitis is a form of tendinitis behind the knee caused by downhill running or walking.
Achilles tendinitis is caused by downhill running, jumping, or other activities that can strain the calf muscles.
Peroneal tendinitis is inflammation of the tendon that is located in the side of the ankle and foot. Excessive hiking, tennis, or many other activities may cause peroneal tendinitis.
De Quervain’s tenosynovitis is a painful inflammation of the tendons on the thumb side of the wrist. De Quervain’s tenosynovitis is caused by repetitive movements of the wrist and hand, such as lifting up young children from under their armpits.