Ulnar Collateral Ligament Injury
Like other joints, the elbow is held together by strong bands of tissue called "ligaments." On the elbow's inner side is the ulnar collateral ligament complex. We call it the "UCL." It's made of three bands that connect the humerus (the upper arm bone) to the lower arm's ulna. The UCL is the elbow ligament most often injured by baseball pitchers and by other athletes who play throwing sports.