An aortic dissection is a condition in which blood gets behind the inner layer of the aorta. Blood starts to fill the space between the layers of the arterial wall. The aorta widens and significantly disrupts blood flow. The patient can experience:

• sudden and severe chest or upper back pain
• anxiety
• diaphoresis
• nausea

Cross-section of aortic dissection (photo)
Brown University (external Web site)

Dissecting aortic aneurysm
eMedicine(external Web site)