The biceps muscle is the muscle in the front of your upper arm. It helps to bend the elbow and rotate the forearm. The biceps has two tendons that arise from the shoulder joint. One is a long, thin tendon located on the front of the shoulder that attaches inside of the shoulder joint. This tendon is known as the long head of the biceps, and is commonly involved in shoulder pain.
Either through injury or overuse, this tendon can become inflamed and painful. Additionally, because of the close proximity of this tendon to other structures in the shoulder, such as the rotator cuff or labrum, the biceps tendon may become damaged when injury to these other structures occur.
Patients with biceps tendonitis complain of pain over the front (anterior) aspect of the shoulder that may be worse with activity. Overhead athletes may notice changes such as weakness, pain, or decreasing serve or pitch velocity.
In most cases, biceps tendonitis can be successfully treated without surgery. Physical therapy and corticosteroid injections work well. In some cases surgery is indicated to remove the portion of the tendon that is found within the shoulder joint, and re-attach the tendon outside of the joint where it is less likely to be irritated.
Further information on this injury can be found in this article on the AAOS OrthoInfo website, an orthopaedic resource center providing expert information.