Injury to the growth plate in the shoulder from repetitive throwing is called Little Leaguer's shoulder. It occurs in young athletes who haven't finished growing yet.

Most often the growth plate gets a small fracture called a stress fracture. The growth plate is a separate piece of fibrous cartilage at the end of the bone. It stays "soft" until the bone has grown as much as it's going to. Then the growth or end plate hardens and connects with the rest of the bone and can no longer be seen on an X-ray.

Baseball pitchers around age 14 are affected the most. Pain with throwing is the main symptom. An X-ray shows an increase in the space between the bone and the growth plate at the end of the bone. Any damage to the growth plate can cause a delay in growing. Treatment is rest, physical therapy, and sometimes, surgery.