The medial collateral ligament (MCL) of the elbow of is part of the complex of ligaments and tendons that attach and stabilize the bones of the lower and upper arm where they meet at the elbow joint. (It should not be confused with the MCL of the knee.)
Sometimes also referred to as the ulnar collateral ligament (UCL), the MCL of the elbow attaches the ulna (which, along with the radius, makes up the bones of the lower arm) to the humerus, the bone of the upper arm.
In most people, injuries to the elbow MCL are rarely caused by stress inflicted on the joint during a throwing motion. But for athletes such as baseball pitchers, javelin throwers or lacrosse players, the forceful repetitive motion of their sport can cause inflammation (swelling), cartilage injuries, bone spurs or even a tear in the ligament.
When the elbow MCL is torn, a person will still have a full range of motion in the elbow, as well the ability to throw. However, he or she will not be able to exert significant force into a throw. Elbow MCL tears are often the result of a gradual process of "attenuation" (weakening) of the ligament. In some cases, it may not be immediately clear that the ligament has been torn, but some people report hearing a pop at the time of injury.
Ulnar collateral ligament reconstruction, commonly known as Tommy John surgery, is a highly successful treatment for elbow MCL tears. Get more detailed information on elbow MCL tears and Tommy John surgery in the articles and other content below.