aorta
Meaning of aorta: Nearly every artery in the body branches from this one vessel, whose elastic wall keeps blood moving between heartbeats.
Definition of aorta
The aorta is the largest artery in the body. It leaves the left ventricle of the heart, arches over, and runs down through the chest and abdomen, giving off the branches that supply the head, arms, organs and legs with oxygen rich blood. It ends by dividing into the two arteries that carry blood into the pelvis and lower limbs.
What are its sections?
| Section | Where it runs and what leaves it |
|---|---|
| Ascending aorta | Rises from the heart valve; the arteries feeding the heart muscle itself branch off first |
| Arch | Curves over the top; sends branches to the head, neck and arms |
| Descending thoracic aorta | Runs down behind the chest, supplying the chest wall and airways |
| Abdominal aorta | Continues through the abdomen, supplying gut, liver, spleen and kidneys before dividing |
Every named artery of the body circuit is descended from one of these branches, which is why a blockage or tear at the aorta itself can starve territory far away from where the problem sits. The arteries to the heart muscle leaving first, just above the valve, is a detail with consequences: the heart is supplied at the very start of the line.
Why does its wall need to be elastic?
Blood does not leave the heart in a steady stream. It arrives in bursts, one per beat. The aortic wall is packed with elastic fibers that let it balloon slightly as each burst arrives and then recoil as the heart relaxes, squeezing the stored volume onward. The effect is to convert a series of pulses into something closer to continuous flow, so that the smaller vessels downstream and the organs beyond them are not battered by the peaks. The wall stiffens with age, which blunts that cushioning and is one reason the upper reading of a blood pressure measurement tends to rise over a lifetime.
What goes wrong with it?
Three problems dominate. An aneurysm is a weakened section that widens over time; it usually causes nothing at all until it leaks or bursts, so most are found during imaging arranged for another reason. A dissection is a tear in the inner lining that allows blood to force its way between the layers of the wall, typically announcing itself with sudden severe tearing pain. Narrowing from plaque affects the aorta as it does other arteries, and a narrowing present from birth restricts flow to the lower body. High blood pressure is the thread running through most of these, since the wall is under constant load and any weakness is worked on relentlessly by the pressure inside.
Used in a sentence
Imaging of the aorta was performed to evaluate for aneurysmal dilation.
Good to know
The term aorta refers specifically to this single largest vessel, distinct from the many individually named arteries that branch from it to supply particular organs and regions.
Word origin
Where “aorta” comes from
From Greek aorte, related to aeirein, meaning to lift or raise.