Abdominal aorta

Abdominal aorta
The abdominal aorta and its branches.
Details
Source	Thoracic aorta
Branches	Celiac artery, superior mesenteric artery, inferior mesenteric artery, common iliac 6 others
Vein	Inferior vena cava
Identifiers
Latin	Aorta abdominalis, pars abdominalis aortae
MeSH	A07.231.114.056.205
Dorlands /Elsevier	p_07/12616144
TA	A12.2.12.001
FMA	3789
Anatomical terminology []

The abdominal aorta is the largest artery in the abdominal cavity. As part of the aorta, it is a direct continuation of the descending aorta (of the thorax).

The abdominal aorta begins at the level of the diaphragm, crossing it via the aortic hiatus, technically behind the diaphragm, at the vertebral level of T12. It travels down the posterior wall of the abdomen, anterior to the vertebral column. It thus follows the curvature of the lumbar vertebrae, that is, convex anteriorly. The peak of this convexity is at the level of the third lumbar vertebra (L3). It runs parallel to the inferior vena cava, which is located just to the right of the abdominal aorta, and becomes smaller in diameter as it gives off branches. This is thought to be due to the large size of its principal branches. At the 11th rib, the diameter is 122mm long and 55mm wide and this is because of the constant pressure.

The abdominal aorta is clinically divided into 2 segments:

The abdominal aorta supplies blood to much of the abdominal cavity. It begins at T12, and usually has the following branches:

Note that the bifurcation (union) of the inferior vena cava is at L5 and therefore below that of the bifurcation of the aorta.

The abdominal aorta lies slightly to the left of the midline of the body. It is covered, anteriorly, by the lesser omentum and stomach, behind which are the branches of the celiac artery and the celiac plexus; below these, by the lienal vein (splenic vein), the pancreas, the left renal vein, the inferior part of the duodenum, the mesentery, and aortic plexus.

Posteriorly, it is separated from the lumbar vertebræ and intervertebral fibrocartilages by the anterior longitudinal ligament and left lumbar veins.