Nonpenetrating cardiac injuries due to direct precordial blunt impacts are a commonly encountered phenomenon in medicolegal offices. These injuries vary from contusions to valvular lacerations, or papillary muscle rupture to coronary arterial injury with resulting infarction. A less commonly occurring manifestation of nonpenetrating injury is a concussion of the heart (commotio cordis), often with dramatic physiological consequences but no morphologic cardiac injury. We describe four case reports of this entity. The cases were collected over a 5-year period (1978-1983) from the Wayne County Medical Examiner's Office in Detroit, Michigan.