Anatomy of the Elbow

The elbow is a complex joint that allows bending and straightening (flexion and extension), and forearm rotation (pronation, palm down; and supination, palm up). The elbow is formed by the joining of three bones: the upper arm (humerus), the forearm on the pinky finger side (ulna), and the forearm on the thumb side (radius). The surfaces of these bones, where they meet to form the joint, are covered with articular cartilage, a smooth substance that protects the bones and acts as a natural cushion to absorb forces across the joint. A thin, smooth tissue, called synovial membrane, covers all remaining surfaces inside the elbow joint. In a healthy elbow, this membrane makes a small amount of fluid that lubricates the cartilage and eliminates almost all friction as you bend and rotate your arm.

Held together by muscles, ligaments and tendons, the elbow is a combination hinge and pivot joint. The hinge part of the elbow allows the arm to bend like the hinge of a door, while the pivot part makes it possible for the lower arm to twist and rotate. There are several muscles, nerves and tendons that cross at the elbow.

What Are Throwing Injuries to the Elbow in Children?

The beginning of baseball season in spring is often followed by an increase in overuse injuries in young baseball players, particularly pitchers and other players who throw repetitively. Two of the most frequent throwing injuries to the elbow are medial apophysitis (little leaguer’s elbow), and osteochondritis dissecans.

  • Medial apophysitis (little leaguer’s elbow)—When repetitive throwing creates an excessively strong pull on the tendons and ligaments of the elbow, an injury can occur, causing pain at the knobby bump on the inside of the elbow. Little leaguer’s elbow can be serious if it becomes aggravated. Repeated pulling can tear ligaments and tendons away from the bone, taking tiny bone fragments with it, just as a plant takes soil with it when uprooted. This can disrupt normal bone growth, resulting in deformity.
  • Osteochondritis dissecans—Less common than little leaguer’s elbow, this condition is also caused by excessive throwing and may be the source of pain on the outside of the elbow. Muscles work in pairs, so if there is pulling on one side of the elbow, there is pushing on the other side. As the elbow is compressed, the joint smashes immature bones together. This can loosen or fragment the bone and cartilage, resulting in osteochondritis dissecans.

Symptoms of Throwing Injuries

Elbow pain, restricted range of motion and locking of the elbow joint are the most common symptoms. If any of these symptoms appear, your child should stop throwing and the elbow should be examined by a physician. When left untreated, throwing injuries to the elbow can develop into complicated conditions.

Nonsurgical Treatment

Younger children tend to respond better to nonsurgical treatments. Resting the injured elbow is critical. Continued throwing may lead to major complications and jeopardize the child’s ability to actively participate in a sport that requires throwing. Ice packs can be used to help bring down any swelling. If pain persists after a few days of complete rest of the affected area, or if pain recurs when throwing is resumed, stop the activity again until your child receives medical treatment. You may also need to discuss a refined throwing technique with your child’s doctor and coach.

Surgery

Occasionally, surgical treatment is necessary, especially for girls older than 12 years, or boys older than 14 years. Depending upon your child’s injury, surgery may involve removing loose bone fragments, bone grafting, or reattaching a ligament to the bone.

Preventing Throwing Injuries to a Child’s Elbow

There are general guidelines regarding how many pitches a child can safely throw each week. This includes both practice and competitive play. To prevent throwing injuries, young pitchers should play no more than three or four innings each game.

  • Ages 7 to 8—Throw no more than 50 pitches per week.
  • Ages 9 to 10—Throw no more than 75 pitches per week.
  • Ages 11 to 12—Throw no more than 85 pitches per week.
  • Ages 13 to 16—Throw no more than 95 pitches per week.
  • Ages 17 to 18—Throw no more than 105 pitches per week.

VIDEO: Throwing Injuries with Kirk Cousins & Dr. Bruce Stewart, Holland Hospital Sports Medicine

Click here for more information on preventing baseball injuries, or to download injury prevention guidelines for a variety of sports.