Head injuries in children are a more common occurrence than is often realized. Types of injuries that can cause brain damage in children include car accidents, bicycle accidents, falls, sports injuries and child abuse. Head injury in children causes brain injury that is different from adult brain injury. In children, it is more difficult to ascertain the amount of brain functions that have been lost. Adult brain injury victims have prior knowledge, test scores and other quantifiable data to rely on when measuring loss of brain function. Children with head injuries may not show symptoms for several years. There are areas of the brain, such as the frontal lobe, that do not fully develop until late in childhood growth. Injury to the frontal lobe may not become apparent until the age at which the frontal lobe should have been developed. The same is true for skills that a small child would not have, for example, damage to the brain that affects reading or writing might not become apparent until the child is of school age. The frontal lobe continues to develop until around the age of 16, leaving many years for brain damage in children to become apparent even years after the injury occurred.