Shaken baby syndrome (also called intentional head injury, or IHI) is brain damage that occurs when a baby is shaken, slammed, or thrown against an object. It is a form of child abuse that occurs when the baby's caregiver loses control.

Shaking a baby or striking a baby's head is always dangerous. Babies' heads are large in relationship to their bodies, and their neck muscles are not well developed. If a baby is forcefully shaken, slammed, or thrown, his or her head will jerk back and forth uncontrollably. The child’s skull can hit the brain with force. When the inside of the skull forcefully strikes the brain, it can cause:

• Bruising, swelling, or tearing of the brain tissue. Brain injury and bleeding can cause increased pressure in the brain, which can lead to serious, permanent brain damage.
• Damage to the blood vessels at the back of the eye, which may cause bleeding inside the eye (retinal hemorrhage), vision problems, or blindness.
• Death.