A charley horse is a term for a painful contusion (bruise) of the quariceps muscle of the anterior thigh that commonly results in a muscular hematoma and sometimes several weeks of pain and disability. It often occurs in sports when an athlete is struck by an opponent's knee, in a manner like the kick of a horse, perhaps the reason for its name. In the UK and Commonwealth countries, such an injury is known as a dead leg. In Australia this is also known as a corked thigh or "corkie"