Extensor carpi ulnaris (ECU) tendinitis refers to inflammation of the extensor carpi ulnaris tendon and/or the tendon lining, causing pain, tenderness, redness, and restricted wrist movement. In most cases, the pain associated with extensor carpi ulnaris tendinitis worsens when straightening the wrist, bending it toward the little finger, or making a gripping formation. The most common causes of extensor carpi ulnaris (ECU) tendinitis are overuse injuries, trauma to the tendon, and weak wrists and forearms. Athletes who play a sport that requires gripping or repetitive hand or wrist motion as well as individuals whose job requires heavy labor are at an increased risk of sustaining extensor carpi ulnaris tendinitis. To prevent this injury, it’s important to properly warm up muscles before beginning any activity and to maintain strength in the wrist and hand. With conservative treatment, most people recover from extensor carpi ulnaris tendinitis within two months. Conservative treatment typically involves ice, pain-relieving medication, and physical therapy, which may include rehabilitative exercises such as those designed to flex and extend the wrist and strengthen and stretch the muscles in the wrist, hand, and forearm. Most programs also will include education to prevent the injury from recurring.