abdominal aorta
Summary
The abdominal aorta is the continuation of the thoracic aorta below the diaphragm (T12) to its bifurcation into the common iliac arteries at L4. It supplies blood to the abdominal organs, gastrointestinal tract, kidneys, and lower limbs via its major branches. Clinically significant for abdominal aortic aneurysm (AAA) formation, atherosclerosis, and as a landmark in retroperitoneal anatomy.
Detail
The abdominal aorta begins as the thoracic aorta passes through the aortic hiatus of the diaphragm at the T12 vertebral level and terminates at L4 where it bifurcates into the right and left common iliac arteries. It gives rise to unpaired anterior visceral branches (celiac trunk at T12, superior mesenteric artery at L1, inferior mesenteric artery at L3) supplying the GI tract, paired lateral visceral branches (renal arteries at L1-L2, suprarenal arteries, gonadal/testicular/ovarian arteries), and paired parietal branches (inferior phrenic, lumbar arteries, and median sacral artery terminally).
Clinical significance: Abdominal aortic aneurysm (AAA) is the most important pathology, typically occurring infrarenally due to atherosclerosis, with risk factors including smoking, hypertension, male sex, and age >65. AAA screening with ultrasound is recommended for men 65-75 with smoking history. Rupture presents with the classic triad of abdominal/back pain, pulsatile abdominal mass, and hypotension - a surgical emergency with high mortality. Atherosclerotic disease of the abdominal aorta can also cause Leriche syndrome (aortoiliac occlusive disease) presenting with claudication, impotence, and diminished femoral pulses. The abdominal aorta is also a common site for atheroma-related emboli and can be affected by aortic dissection (though less common than thoracic dissection). Retroperitoneal location makes it relevant to retroperitoneal structures and surgical approaches (e.g., during AAA repair, care must be taken regarding the renal arteries, inferior mesenteric artery, and the ureters crossing anteriorly at the bifurcation).
Sources
- Moore's Clinically Oriented Anatomy
- Gray's Anatomy for Students
- First Aid for the USMLE Step 1
- Robbins and Cotran Pathologic Basis of Disease
Reviewed by AnkiBoss editorial — medical student review. Information here is for study reference only and is not medical advice. Spotted an error? Let us know.