The subcostal arteries, so named because they lie below the last ribs, constitute the lowest pair of branches derived from the thoracic aorta

Thoracic aorta

The thoracic aorta is contained in the posterior mediastinal cavity.It begins at the lower border of the fourth thoracic vertebra where it is continuous with the aortic arch, and ends in front of the lower border of the twelfth thoracic vertebra, at the aortic hiatus in the diaphragm where it...

, and are in series with the intercostal arteries

Intercostal arteries

The intercostal arteries are a group of arteries that supply the area between the ribs , called the intercostal space.* Highest intercostal artery - first and second intercostal spaces...

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Each passes along the lower border of the twelfth rib behind the kidney

Kidney

The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...

 and in front of the Quadratus lumborum muscle

Quadratus lumborum muscle

The Quadratus lumborum is irregular and quadrilateral in shape, and broader below than above.-Origin and insertion:It arises by aponeurotic fibers from the iliolumbar ligament and the adjacent portion of the iliac crest for about 5 cm., and is inserted into the lower border of the last rib for...

, and is accompanied by the twelfth thoracic nerve.

It then pierces the posterior aponeurosis of the Transversus abdominis, and, passing forward between this muscle and the Obliquus internus, anastomoses with the superior epigastric, lower intercostal, and lumbar arteries

Lumbar arteries

The lumbar arteries are in parallel with the intercostals.They are usually four in number on either side, and arise from the back of the aorta, opposite the bodies of the upper four lumbar vertebræ....

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Each subcostal artery gives off a posterior branch which has a similar distribution to the posterior ramus of an intercostal artery.

External links

- "Branches of the ascending aorta

Ascending aorta

The ascending aorta is a portion of the aorta commencing at the upper part of the base of the left ventricle, on a level with the lower border of the third costal cartilage behind the left half of the sternum; it passes obliquely upward, forward, and to the right, in the direction of the heart’s...

, arch of the aorta, and the descending aorta

Descending aorta

The descending aorta is part of the aorta, the largest artery in the body. The descending aorta is the part of the aorta beginning at the aortic arch that runs down through the chest and abdomen. The descending aorta is divided into two portions, the thoracic and abdominal, in correspondence with...

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