A greenstick fracture is a type of bone injury that occurs when a bone bends and partially breaks, similar to how a young twig bends and splinters. This type of fracture is most common in children because their bones are softer and more flexible than those of adults. Typically, a greenstick fracture affects long bones, such as those in the arms or legs. Symptoms may include pain, swelling, and difficulty moving the affected limb. Treatment often involves immobilization with a cast or splint to allow the bone to heal properly.