OBJECTIVE: To identify the types of injuries the human brain incurs as a result of traumatic forces applied to the cranium. In athletic events and endeavors, the full spectrum of intracranial hemorrhages in various compartments, raised intracranial pressure, and diffuse nonhemorrhagic damage may be seen. In this review, we describe these serious injuries and the more common mild traumatic brain injury in their clinical presentations and relate concussion classification to the overall picture of traumatic brain injury. METHODS: Our cumulative experience with athletic injuries, both at the catastrophic and mild traumatic brain injury levels, has led us to a management paradigm that serves to guide us in the classification and treatment of these athletes. DISCUSSION: The occurrence of intracranial injuries in sports has now been well documented. Intracranial hematomas (epidural, subdural, and parenchymal) and cerebral contusions can result from head injury. Many patients sustain a diffuse brain injury, resulting in elevated intracranial pressures, without a blood clot or mass lesion. The classification of concussion and the use of concussion guidelines are not uniform. However, the major emphases are agreed upon: the close and careful scrutiny of the athlete, an expeditious but reliable neurologic examination, and proper on-field management. Return-to-play decisions are based on many factors that affect normal functioning, both on and off the playing field. CONCLUSIONS: Sufficient knowledge now exists to allow us to carefully evaluate the injured athlete, to place him or her in the management scheme to minimize the potential for permanent cerebral dysfunction, and to know when the athlete can safely return to contact sport participation.