Head injury can be classified as either closed or penetrating. In closed head injury, the head sustains a blunt force by striking against an object. In penetrating head injuries, a high velocity object breaks through the skull and enters the brain. The signs and symptoms of a head injury may occur immediately or develop slowly over several hours.
Review Date: 1/1/2013 Reviewed By: Jacob L. Heller, MD, MHA, Emergency Medicine, Virginia Mason Medical Center, Seattle, Washington. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, David R. Eltz, Stephanie Slon, and Nissi Wang.