If you've got a tween or teen who's been injured, you’ve likely heard of growth plates, the body parts where 15 to 30 percent of all childhood fractures occur, according to the American Academy of Orthopaedic Surgeons (AAOS).

Growth plates are thin cartilage discs that develop at the end of long bones, and they're the weakest parts of a child’s skeleton. The tissue hardens into bone after adolescence, but until that time, the risk of bone fractures can be high, according to the Cleveland Clinic.

Are they easy to injure?

Growth plate injuries are twice as likely to occur in boys as in girls (girls’ bones strengthen quicker) according to the Children's Hospital of Philadelphia. Injuries can occur in the thigh, leg and wrist bones. Plates continue to grow until about age 14 for girls and age 16 for boys, says the Cleveland Clinic.

What activities put them at risk?

Thirty percent of injuries are from contact sports like basketball, soccer and football, and another 20 percent are from recreational activities like skateboarding and skiing, says the AAOS. A pick-up basketball game, bike ride or jog around the block could all end in a fall or potentially serious injury.

How do they heal?

Most growth plate fractures can be healed with a cast, but surgery may be necessary if the bone is displaced. Limbs can grow crooked or unequal in length, says the AAOS. If he’s experiencing pain, tenderness, swelling or an inability to move the injured area, see a doctor immediately.