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).
It 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 about 25 mm; above the origin of the renal arteries, 22 mm; below the renals, 20 mm; and at the bifurcation, 19 mm.
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.thumb|right|350px|Contrast enhanced MRA of the abdominal aorta demonstrating normal paired arteries.
- inferior phrenic a.
- celiac a.
- left gastric a.
- splenic a.
- short gastric arteries (6)
- splenic arteries (6)
- left gastroepiploic a.
- hepatic a.
- cystic a.
- right gastric a.
- gastroduodenal a.