The aorta is the largest artery leaving the heart carrying oxygenated blood to the entire body. An aortic dissection is a tear in the wall or lining of the aorta.

The wall of the aorta has three layers. When the inside layer is torn the pressure of the pumped blood can cause the tear to expand up and down the aorta -- this is called a dissection.

As the blood accumulates in the wall it weakens the outer layers of the aorta. If this continues the outer wall of the aorta can burst.

It is a very serious condition that requires emergency treatment. Unfortunately, it is often fatal.

Aortic dissection is more common in men and is usually caused by chronic high blood pressure, but it can also be caused by congenital problems with the aorta as well as other inherited disorders such as Marfan's Syndrome, which is a disease that affects the connective tissues that are part of the arteries in the body.

(-- CBS News Health Correspondent Dr. Emily Senay)

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