There are three tendons — tough connective tissues that attach muscle to bone — around the biceps. One tendon connects the muscle to the bone at the elbow, and two more connect it to the bones of the shoulder. These tendons work with the muscle to allow for rotating and lifting movement in the arms. Tendons, like muscles, are generally pretty sturdy, but overuse can damage them, causing pain and swelling. For example, tendonitis is caused by repetitive motion in the shoulders and arms, which makes biceps tendonitis a common injury among golfers, swimmers, and people who play racquet sports like tennis or baseball. People with certain jobs that require repetitive arm movements are also at risk.
Overuse isn’t the only source of tendon damage; sudden injuries such as tears are also possible. In the case of strain from overuse, the tendon is already weakened, which can cause it to tear if used the wrong way. Even without previous strain, however, a tear can occur from a sharp twist in the wrong direction or a bad fall on an outstretched arm. The most common source of a tendon tear is lifting an object that is far too heavy, especially in the elbow.
Tears can occur at either the shoulder or the elbow, and they range in severity from partial to complete (a complete tear means the tendon has completely torn away from the bone and is no longer connecting it to the muscle). Signs of a tear include sharp, sudden pain, an audible “popping” noise, limited ability to rotate the arm, and even a noticeable difference on the surface of the arm, such as bulge.
Depending on the type and severity of the tendon injury, surgery may be required. Consult a medical professional for tests and diagnoses.