human anatomy The human body is the structure of a human being. It is composed of many different types of cells that together create tissues and subsequently organ systems. They ensure homeostasis and the viability of the human body. It comprises a he ...

, the abdominal aorta is the largest

artery An artery (plural arteries) () is a blood vessel in humans and most animals that takes blood away from the heart to one or more parts of the body (tissues, lungs, brain etc.). Most arteries carry oxygenated blood; the two exceptions are the pul ...

in the

abdominal cavity The abdominal cavity is a large body cavity in humans and many other animals that contains many organs. It is a part of the abdominopelvic cavity. It is located below the thoracic cavity, and above the pelvic cavity. Its dome-shaped roof is the th ...

. As part of the

aorta The aorta ( ) is the main and largest artery in the human body, originating from the left ventricle of the heart and extending down to the abdomen, where it splits into two smaller arteries (the common iliac arteries). The aorta distributes ...

, it is a direct continuation of 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 ...

(of the thorax).

Structure

The abdominal aorta begins at the level of the diaphragm, crossing it via the

aortic hiatus The aortic hiatus is a hole in the diaphragm. It is the lowest and most posterior of the large apertures. It is located approximately at the level of the twelfth thoracic vertebra (T12). Structure Strictly speaking, it is not an aperture in the ...

, 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 The inferior vena cava is a large vein that carries the deoxygenated blood from the lower and middle body into the right atrium of the heart. It is formed by the joining of the right and the left common iliac veins, usually at the level of the ...

, 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 suprarenal abdominal or paravisceral segment, inferior to the diaphragm but superior to the renal arteries. # The Infrarenal segment, inferior to the renal arteries and superior to the iliac bifurcation.

Branches

The abdominal aorta supplies blood to much of the abdominal cavity. It begins at T12 and ends at L4 with its bifurcation into the common iliac arteries and usually has the following branches: Note that the bifurcation (union) of the

is at L5 and therefore below that of the bifurcation of the aorta. Volume rendered CT scan of abdominal and pelvic blood vessels (smaller)

# inferior phrenic a. # celiac a. ## left gastric a. ## splenic a. ### short gastric arteries (6) ### splenic arteries (6) ### left gastroepiploic a. ### pancreatic arteries ## common hepatic a. ### right gastric a. ### gastroduodenal a. #### right gastroepiploic a. #### superior pancreaticoduodenal a. ### right hepatic a. #### cystic a. ### left hepatic a. # superior mesenteric a. ## inferior pancreaticoduodenal a. ## jejunal and ileal arteries ## middle colic a. ## right colic a. ## ileocolic a ### anterior cecal a. ### posterior cecal a. – appendicular a. ### ileal a. ### colic a. # middle suprarenal a. # renal a. # testicular or ovarian a. # four lumbar arteries # inferior mesenteric a. ## left colic a. ## sigmoid arteries (2 or 3) ## superior rectal a. # median sacral a. # common iliac a. ## external iliac a. ## internal iliac a.

Relations

The abdominal aorta lies slightly to the left of the midline of the body. It is covered, anteriorly, by the

lesser omentum The lesser omentum (small omentum or gastrohepatic omentum) is the double layer of peritoneum that extends from the liver to the lesser curvature of the stomach, and to the first part of the duodenum. The lesser omentum is usually divided into th ...

and

stomach The stomach is a muscular, hollow organ in the gastrointestinal tract of humans and many other animals, including several invertebrates. The stomach has a dilated structure and functions as a vital organ in the digestive system. The stomach i ...

, behind which are the branches of the celiac artery and the celiac plexus; below these, by the

lienal vein The spleen is an organ found in almost all vertebrates. Similar in structure to a large lymph node, it acts primarily as a blood filter. The word spleen comes .

(splenic vein), are the

pancreas The pancreas is an organ of the digestive system and endocrine system of vertebrates. In humans, it is located in the abdomen behind the stomach and functions as a gland. The pancreas is a mixed or heterocrine gland, i.e. it has both an end ...

, the left

renal vein The renal veins are large-calibre veins that drain blood filtered by the kidneys into the inferior vena cava. There is one renal vein draining each kidney. Because the inferior vena cava is on the right half of the body, the left renal vein is lo ...

, the inferior part of the

duodenum The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear, and the terms anterior intestine or proximal intestine m ...

, the mesentery, and the aortic plexus. Posteriorly, it is separated from the lumbar vertebræ and intervertebral fibrocartilages by the

anterior longitudinal ligament The anterior longitudinal ligament is a ligament that runs down the anterior surface of the spine. It traverses all of the vertebral bodies and intervertebral discs on their ventral side. It may be partially cut to treat certain abnormal curvatur ...

and left lumbar veins. On the right side it is in relation above with the

azygos vein The azygos vein is a vein running up the right side of the thoracic vertebral column draining itself towards the superior vena cava. It connects the systems of superior vena cava and inferior vena cava and can provide an alternative path for blood ...

cisterna chyli The cisterna chyli (or cysterna chyli, and etymologically more correct, receptaculum chyli) is a dilated sac at the lower end of the thoracic duct in most mammals into which lymph from the intestinal trunk and two lumbar lymphatic trunks flow. It ...

thoracic duct In human anatomy, the thoracic duct is the larger of the two lymph ducts of the lymphatic system. It is also known as the ''left lymphatic duct'', ''alimentary duct'', ''chyliferous duct'', and ''Van Hoorne's canal''. The other duct is the right ...

, and the right crus of the diaphragm—the last separating it from the upper part of the

, and from the right celiac ganglion; the inferior vena cava is in contact with the aorta below. On the left side are the left crus of the diaphragm, the left celiac ganglion, the ascending part of the duodenum, and some coils of the

small intestine The small intestine or small bowel is an organ in the gastrointestinal tract where most of the absorption of nutrients from food takes place. It lies between the stomach and large intestine, and receives bile and pancreatic juice through the p ...

Relationship with inferior vena cava

The abdominal aorta's venous counterpart, the

(IVC), travels parallel to it on its right side. * Above the level of the umbilicus, the aorta is somewhat posterior to the IVC, sending the right renal artery travelling behind it. The IVC likewise sends its opposite side counterpart, the

left renal vein The renal veins are large-calibre veins that drain blood filtered by the kidneys into the inferior vena cava. There is one renal vein draining each kidney. Because the inferior vena cava is on the right half of the body, the left renal vein is lo ...

, crossing in front of the aorta. * Below the level of the umbilicus, the situation is generally reversed, with the aorta sending its right

common iliac artery The common iliac artery is a large artery of the abdomen paired on each side. It originates from the aortic bifurcation at the level of the 4th lumbar vertebra. It ends in front of the sacroiliac joint, one on either side, and each bifurcates i ...

to cross its opposite side counterpart (the left

common iliac vein In human anatomy, the common iliac veins are formed by the external iliac veins and internal iliac veins. The left and right common iliac veins come together in the abdomen at the level of the fifth lumbar vertebra, forming the inferior vena c ...

) anteriorly.

Collateral circulation

The collateral circulation would be carried on by the anastomoses between the

internal thoracic artery In human anatomy, the internal thoracic artery (ITA), previously commonly known as the internal mammary artery (a name still common among surgeons), is an artery that supplies the anterior chest wall and the breasts. It is a paired artery, with on ...

and the

inferior epigastric artery In human anatomy, inferior epigastric artery refers to the artery that arises from the external iliac artery. It anastomoses with the superior epigastric artery. Along its course, it is accompanied by a similarly named vein, the inferior epig ...

; by the free communication between the superior and inferior mesenterics, if the ligature were placed between these vessels; or by the anastomosis between the inferior mesenteric artery and the

internal pudendal artery The internal pudendal artery is one of the three pudendal arteries. It branches off the internal iliac artery, and provides blood to the external genitalia. Structure The internal pudendal artery is the terminal branch of the anterior trunk of ...

, when (as is more common) the point of ligature is below the origin of the inferior mesenteric artery; and possibly by the anastomoses of the

lumbar arteries The lumbar arteries are arteries located in the lower back or lumbar region. 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 ...

with the branches of the

internal iliac artery The internal iliac artery (formerly known as the hypogastric artery) is the main artery of the pelvis. Structure The internal iliac artery supplies the walls and viscera of the pelvis, the buttock, the reproductive organs, and the medial compa ...

Clinical significance

Aneurysm

Additional images

File:Abdominal aorta.jpg, Contrast enhanced MRA of the abdominal aorta demonstrating normal paired arteries. File:Gray533.png, The celiac artery and its branches; the stomach has been raised and the peritoneum removed. File:Gray1097.png, Transverse section through the middle of the first lumbar vertebra, showing the relations of the pancreas. File:LDLTA.jpg, CT scan showing the liver and a kidney File:Contrast-enhanced CT scan demonstrating abdominal aortic aneurysm.jpg, A transverse contrast enhanced CT scan demonstrating an abdominal aortic aneurysm of 4.8 by 3.8 cm File:Ultrasonographic measurement of aortic diameter at the navel.svg, The standard aortic measurement on

abdominal ultrasonography Abdominal ultrasonography (also called abdominal ultrasound imaging or abdominal sonography) is a form of medical ultrasonography (medical application of ultrasound technology) to visualise abdominal anatomical structures. It uses transmission a ...

, such as used for

abdominal aortic aneurysm Abdominal aortic aneurysm (AAA) is a localized enlargement of the abdominal aorta such that the diameter is greater than 3 cm or more than 50% larger than normal. They usually cause no symptoms, except during rupture. Occasionally, abdominal, ...

s, is between the outer margins of the aortic wall. File:Abdominal aorta 2.jpg, Abdominal aorta File:Abdominal aorta ultrasound.jpg, Abdominal aorta ultrasound

References

External links

UCC
{{DEFAULTSORT:Abdominal Aorta Arteries of the abdomen Aorta