Aorta - the main artery of the body

The aorta is a large blood vessel that carries blood from the heart to the circulatory system. The aorta originates from the left side of the heart, then bends around the heart and finally runs straight down to the pelvic area.

Function of the aorta

The aorta is the largest artery in the body. Arteries are also known as arteries.

These blood vessels carry blood away from the heart. In contrast, the veins carry the blood towards the heart. There it is re-oxygenated via the small circulation and fed back into the bloodstream via the arteries.

The aorta forms the beginning of this blood circulation away from the heart. It conducts the blood from the left ventricle into the vessels of the large circulation.

In addition, the aorta performs what is known as the Windkessel function and thus regulates the blood flow: while the blood is still ejected from the heart in batches, it later flows in a continuous stream. The aorta ensures this by balancing the pressure, which is made possible by very elastic fibers in the arterial wall.

The aorta runs as an artery (red) from the heart downwards towards the pelvis © pixdesign123 / Fotolia

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Structure of the aorta

The aorta is roughly shaped like an upright walking stick. It initially runs almost vertically upwards from the left side of the heart. This is where the carotid arteries and other blood vessels branch off from the aorta. This then bends 180 degrees in the so-called aortic arch so that it continues downwards. It then runs in a straight line through the chest and abdominal cavity down to the pelvis, where it splits into the two large pelvic arteries.

Numerous smaller arteries branch off from the aorta along its entire course and supply the whole body with oxygen-rich blood. In total, the aorta is around 30 to 40 centimetres long in an adult and has a diameter of around 2.5 to 3.5 centimetres.

© designua / Fotolia

Anatomically, the aorta is divided into different sections:

Aorta ascendens - the ascending aorta

This section of the aorta is only a few centimetres long and runs almost vertically upwards. The ascending aorta originates from the left ventricle and is separated from it by the aortic valve.

Arcus aortae - the aortic arch

The ascending aorta merges into the aortic arch, which changes the direction of the aorta by around 180 degrees. This gives the aorta the approximate shape of a walking stick. The blood vessels that supply the head and arms with blood branch off from the upper part of the aortic arch.

Aorta descendens - the descending aorta:

The descending aorta makes up the largest part of the aorta. It runs vertically downwards and runs through the entire chest and abdominal cavity. In the pelvic area, it finally divides into the two large pelvic arteries. The descending aorta is further divided into subsections:

Aorta thoracica - the thoracic aorta

This part of the descending aorta lies entirely in the chest cavity and supplies the pericardium, oesophagus, lung tissue and intercostal spaces with blood. The thoracic aorta extends to the diaphragm at the level of the twelfth thoracic vertebra.

Aorta abdominalis - the abdominal aorta

After passing through the diaphragm, the main artery is called the abdominal aorta. This is further divided into two segments: The abdominal aorta above the renal arteries supplies blood to the stomach, liver, spleen, pancreas, duodenum and a large part of the intestine. And the abdominal aorta below the renal arteries is responsible for supplying the lower sections of the intestine and the pelvic organs. At the level of the fourth lumbar vertebra, the abdominal aorta divides into the two large pelvic arteries.

Examination methods of the aorta

The doctor has various options for detecting disorders in the aorta. Some information can be obtained by palpation, but in most cases an imaging procedure is necessary. There are various options for this:

• an X-ray of the chest, possibly in conjunction with angiography (the vessels are visualized using a contrast agent)
• an ultrasound examination
• magnetic resonance imaging (MRI)
• computed tomography (CT)
• transesophageal echocardiography (TEE) (an ultrasound probe is swallowed so that the aorta examination can be carried out from the nearby oesophagus)
• Cardiac catheterization (this also allows immediate intervention if problems arise)

Diseases of the aorta

The aorta is vital because it transports all of the body's blood. If it ruptures due to injury or disease, you will bleed to death in a short time. Fortunately, this only happens rarely and can very often be prevented in advance.

A major risk factor for an aortic tear is hardening of the arteries (or arteriosclerosis). Fat, calcium, connective tissue and thrombi (blood clots) build up and narrow the aorta. This can cause major problems: On the one hand, the blood flow is disrupted in this way and the vessel walls are injured, making it easier for them to rupture. Secondly, the deposits disrupt the elastic movement of the aorta and prevent it from contracting sufficiently.

Arteriosclerosis usually only occurs in old age, especially in diabetics, smokers or people who are very overweight. Men are more frequently affected than women. A healthy diet and sufficient exercise (preferably in the fresh air) help to prevent arteriosclerosis.

This can lead toan aneurysm, which also significantly increases the risk of a rupture.

Aortic prosthesis is a surgical option for an enlarged aorta with an increased risk of rupture. In the case of a defective aortic valve, an artificial aortic valve replacement is used.