Our son is a 17-year old junior in high school. He's in track and field sports in the javelin-throwing event. At his last practice he felt a pop along the inside of his elbow after his best throw. After that he hasn't been able to throw worth beans. What happened?

Throwing athletes who experience a pop or sharp pain after throwing or pitching may have an elbow injury. The elbow is a complex joint with three bones and all the soft tissues attached between them.

The most common injury along the medial (inside) of the elbow is a strain or tear of the ulnar collateral ligament (UCL). There are three distinct parts or sections to the UCL. Which one may be affected can be determined by the history and an exam.

For example, if pain occurs when the athlete is just starting to throw, it suggests a UCL tear. If the symptoms don't start until the throw is completed, then it's more likely the soft tissues are getting pinched between two bones along the back of the elbow. This is called a posterior impingement.

An orthopedic surgeon or sports specialist will use special tests and imaging studies to make the diagnosis. Areas of tenderness point to a diagnosis of tendinitis vs. impingement vs. UCL injury. Special loading tests then narrow the diagnosis to the specific tissues involved.

X-rays, CT scans, and/or MRIs can be helpful. CT scans will show if there are any loose fragments in the joint causing impingement. MRIs using contrast dyes may reveal tears in the soft tissues. Treatment is based on the diagnosis once it's made.