The abdominal aorta is the continuation of the thoracic aorta as it passes through the diaphragm at the aortic hiatus (at the level of T12 vertebra). It is a major blood vessel in the body that supplies oxygenated blood to the abdominal organs, pelvic structures, and lower limbs.
Anatomy of the Abdominal Aorta
Location
- The abdominal aorta begins at the aortic hiatus of the diaphragm (T12 vertebral level) and descends retroperitoneally in the midline.
- It terminates at the L4 vertebral level, where it bifurcates into the right and left common iliac arteries.
Branches
The abdominal aorta gives off several branches, classified into three main groups:
- Anterior Branches (Unpaired):
- Celiac trunk: Supplies the stomach, spleen, liver, pancreas, and duodenum.
- Superior mesenteric artery: Supplies the small intestine and part of the large intestine.
- Inferior mesenteric artery: Supplies the distal colon and rectum.
- Lateral Branches (Paired):
- Renal arteries: Supply the kidneys.
- Gonadal arteries: Supply the testes in males and ovaries in females.
- Middle suprarenal arteries: Supply the adrenal glands.
- Posterior Branches:
- Lumbar arteries: Supply the muscles and skin of the back.
- Median sacral artery: Supplies the sacrum and coccyx.
Dimensions
- Normal diameter: Approximately 2 cm in adults.
- Enlargement beyond 3 cm is considered an aneurysm.
Function
The abdominal aorta is the primary conduit for delivering oxygenated blood from the heart to the abdominal organs, pelvic region, and lower limbs. Its branches ensure efficient blood supply for digestion, excretion, and other vital functions.
Clinical Significance
Abdominal Aortic Aneurysm (AAA)
- A localized dilation of the abdominal aorta, typically at or below the level of the renal arteries.
- Risk factors: Age, smoking, hypertension, and atherosclerosis.
- Management: May involve surgical repair or endovascular stenting.
Aortic Dissection
- A tear in the wall of the aorta, causing blood to flow between its layers.
- A potentially life-threatening condition requiring immediate medical intervention.
Diagnostic Techniques
- Ultrasound: Commonly used for screening and diagnosis of AAA.
- CT Angiography: Provides detailed imaging for pre-surgical planning.
- MRI: Used for detailed vascular imaging in complex cases.