The abuser holds the baby with both hands by the chest, squeezes and shakes him or her violently back and forth in an effort to stop the baby's crying. The baby's head, swinging on the end of the neck, suffers violent forces of acceleration and deceleration, similar to whiplash injury but repetitive. This extreme force causes the brain to strike forcefully against the inner surface of the skull, with direct bruising and damage. The resultant pressure on the brain from both of these factors increases the amount of resultant permanent brain damage .
Retinal hemorrhage is essentially diagnostic of the condition.
Fractures of the posterior ribs in a child are again almost diagnostic of abuse unless the child is known to have been struck by a car. Awareness of this syndrome is increasing, especially since the celebrated Boston au pair case. Unexplained unconsciousness or difficulty arousing a very young child might be a sign of serious abuse and should be investigated quickly and completely, especially in a situation involving a babysitter. Your child's life could depend on it. And no, I don't mean horseplay or tickling.