Concussion is a common medical problem with significant morbidity and sometimes devastating consequences. Awareness of this injury has increased dramatically in recent years, and our understanding of its pathophysiology and treatment is rapidly evolving. This article reviews the current concepts of concussion pathophysiology and epidemiology, and will provide an overview of proper diagnosis and management. Complications and risk reduction also will be reviewed. By understanding the essentials of concussion medicine, health care professionals will be equipped to manage this injury, including common complications.