The skull is very protective, so hitting it rarely results in injuries to the skull itself. But if the force is great, the neck, the back, and soft tissues inside the head can be injured.

What to Do Immediately: If the person is unconscious, call 911. If the struck area is bleeding, treat it as you would any other cut, but follow up with your doctor, as there may be internal injuries. Icing a small bump can help reduce the swelling.

What Not to Do: Leave the victim alone, especially when he’s sleeping. Wake him up every three to four hours and have him answer simple questions to make sure there’s no brain injury, such as a concussion.

When to Seek Medical Attention: Call 911 if the victim exhibits seizures, dizziness, vomiting, nausea, or obvious changes in behavior.