Head Trauma

General Principles


  • Traumatic brain injury (TBI) can occur with head injury due to contact and/or acceleration/deceleration forces.
  • Concussion: Trauma-induced alteration in mental status with normal radiographic studies that may or may not involve loss of consciousness.
  • Contusion: Trauma-induced lesion consisting of punctate hemorrhages and surrounding edema.


  • Closed head injuries may produce diffuse axonal injury.
  • Contusion or hemorrhage can occur at the site of initial impact, “coup injury,” or opposite to the side of impact, “countercoup injury.”
  • Penetrating injuries (including depressed skull fracture) or foreign objects cause brain injury directly.
  • Secondary increases in intracranial pressure may compromise cerebral perfusion.


  • Head injury is the most common cause of neurologic illness in young people.
  • The overall incidence of TBI in the US population is estimated at approximately 750 per 100,000 (i.e., approximately 2.5 million per year with approximately 11% requiring hospitalization).1
  • Two-thirds of TBIs are considered “mild,” whereas 20% are severe and 10% are fatal. Note that although designated as “mild,” mild TBI can still translate into significant disability (permanent in 15%).
  • Rates of TBI are highest in the very young, adolescents, and the elderly.

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