The subcostal arteries, so named because they lie below the last

ribs The rib cage or thoracic cage is an endoskeletal enclosure in the thorax of most vertebrates that comprises the ribs, vertebral column and sternum, which protect the vital organs of the thoracic cavity, such as the heart, lungs and great vessels ...

, constitute the lowest pair of branches derived from the thoracic aorta, and are in series with the

intercostal arteries The intercostal arteries are a group of arteries passing within an intercostal space (the space between two adjacent ribs). There are 9 anterior and 11 posterior intercostal arteries on each side of the body. The anterior intercostal arteries a ...

Anatomy

Course and relations

Each intercostal artery is accompanied by the corresponding (i.e. ipsilateral) subcostal vein and

nerve A nerve is an enclosed, cable-like bundle of nerve fibers (called axons). Nerves have historically been considered the basic units of the peripheral nervous system. A nerve provides a common pathway for the Electrochemistry, electrochemical nerv ...

. Each passes along the lower border of the 12th rib. Before entering the

anterior abdominal wall In anatomy, the abdominal wall represents the boundaries of the abdominal cavity. The abdominal wall is split into the anterolateral and posterior walls. There is a common set of layers covering and forming all the walls: the deepest being the v ...

, each runs laterally upon the anterior surface of the

lumbar fascia The lumbar fascia is the lumbar portion of the thoracolumbar fascia. It consists of three fascial layers - posterior, middle, and anterior - that enclose two (anterior and posterior) muscular compartments. The anterior and middle layers occur only ...

(and thus also anterior to the underlying quadratus lumborum muscle which the lumbar fascia envelops) posterior to the ipsilateral kidney. It then pierces the posterior aponeurosis of the transversus abdominis, thus entering the anterior abdominal wall to course in between the

abdominal internal oblique muscle The abdominal internal oblique muscle, also internal oblique muscle or interior oblique, is an abdominal muscle in the abdominal wall that lies below the external oblique muscle and just above the transverse abdominal muscle. Structure Its fib ...

and

transverse abdominal muscle The transverse abdominal muscle (TVA), also known as the transverse abdominis, transversalis muscle and transversus abdominis muscle, is a muscle layer of the anterior and lateral (front and side) abdominal wall, deep to (layered below) the inter ...

(the neurovascular plane of the anterior abdominal wall).

Branches

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

Anastomoses

anastomoses An anastomosis (, : anastomoses) is a connection or opening between two things (especially cavities or passages) that are normally diverging or branching, such as between blood vessels, leaf#Veins, leaf veins, or streams. Such a connection may be ...

with the superior epigastric, lower intercostal, and lumbar arteries.

References

External links

* - "Branches of the ascending aorta, arch of the aorta, and the

descending aorta In human anatomy, the descending aorta is part of the aorta, the largest artery in the body. The descending aorta begins at the aortic arch and runs down through the chest and abdomen. The descending aorta anatomically consists of two portions o ...

." {{Authority control Arteries of the thorax