Internal hemorrhage can occur in any part of the body blood accumulates in the body cavity is called body cavity blood, such as abdominal blood, pericardial blood pericardial blood vessels or cardiac injury if the bleeding is small and slow does not produce symptoms of cardiac tamponade is called pericardial hemorrhage. As often found outside the fibrous layer wrapped, inside the presence of concentrated blood components and body fluids in the region, suggesting that intrapericardial hemorrhage is an important factor in the formation of pericardial constriction. 1, the injury caused by high-speed foreign objects: high-speed foreign objects usually refers to gunshot, shrapnel, sharp knife and other high-speed sharp foreign objects penetrate the chest wall and injure the pericardium, heart. This is particularly common in wartime, usually also common. This type of injury often exists simultaneously with chest and abdominal trauma. 2.Injuries caused by violent inward displacement of the broken ends of the fractured sternum or ribs: mostly caused by traffic accidents or industrial accidents. 3.Cardiac injury caused by other reasons: cardiac catheterization, interventional cardiology, pericardial puncture and esophageal foreign body.