Table of contents · 10 sections
In a nutshell. The aorta is the body's largest artery, originating from the left ventricle. Segments: ascending (sinuses of Valsalva + coronary arteries), arch (brachiocephalic trunk, left common carotid, left subclavian), descending thoracic (bronchial, intercostal, mediastinal), abdominal (celiac trunk at Th12, SMA at L1, renal arteries at L1–L2, IMA at L3, bifurcation at L4). Clinical significance: aneurysms (> 5.5 cm thoracic / > 5.5 cm abdominal — indication for intervention), dissection (Type A — surgery, Type B — often conservative), coarctation (often at the level of the ligamentum arteriosum).
1. General characteristics
- Adult aortic length is 30–40 cm.
- Diameter: ascending 3 cm, arch 2.7 cm, descending thoracic 2.4 cm, abdominal 2.0 cm.
- Wall structure: intima, media (elastic and smooth muscle fibers), adventitia (vasa vasorum, sympathetic nerves).
- Predominance of elastic fibers — functions as an "elastic reservoir" for stroke volume.
- Sympathetic innervation is vasomotor.
2. Ascending aorta
- From the aortic valve (LV) to the brachiocephalic trunk.
- Length 5–7 cm, diameter 2.5–3 cm.
- Origin — sinuses of Valsalva (right, left, non-coronary).
- Branches: right coronary artery (from the right sinus), left coronary artery (from the left sinus).
- Transitions into the aortic arch at the level of the right 2nd sternocostal articulation.
3. Aortic arch
- At the level of Th4 (sternal angle).
- Arches over the left main bronchus.
- Branches (3): brachiocephalic trunk, left common carotid artery, left subclavian artery.
- Variants: bovine arch (common trunk for the brachiocephalic and left carotid — 15%), aberrant right subclavian artery.
- The brachiocephalic trunk divides into the right common carotid and right subclavian arteries.
- Transition into the descending thoracic aorta at the level of Th4.
4. Descending thoracic aorta
- From Th4 to Th12 (passing through the aortic hiatus of the diaphragm).
- Branches:
- — Bronchial arteries (supply lung parenchyma; 1 on the right from the 3rd intercostal artery, 2 on the left directly).
- — Mediastinal branches.
- — Esophageal branches.
- — Pericardial branches.
- — Posterior intercostal arteries (pairs 3–11).
- — Superior phrenic arteries.
- Artery of Adamkiewicz — the largest radiculomedullary artery, branching off at Th8–L2 (most commonly on the left); critical in thoracoabdominal aortic surgery.
5. Abdominal aorta
- From Th12 (aortic hiatus of the diaphragm) to L4 (bifurcation into the right and left common iliac arteries).
- Length 13–15 cm, diameter 2 cm (↑ up to 3 cm in 50% of cases with aneurysm).
Unpaired visceral branches
| Branch | Level | Supply area |
|---|---|---|
| Celiac trunk (a. coeliaca) | Th12 | Liver, stomach, spleen, pancreas, duodenum |
| Superior mesenteric artery (SMA, ВБА) | L1 | Pancreas, small intestine, right half of the colon to the middle third of the transverse colon |
| Inferior mesenteric artery (IMA, НБА) | L3 | Left half of the colon (from the distal third of the transverse colon to the upper rectum) |
Paired visceral and parietal branches
- Middle suprarenal arteries (L1).
- Renal arteries (L1–L2).
- Gonadal arteries (L2) — ovarian/testicular.
- Inferior phrenic arteries.
- Lumbar arteries (L1–L4) — 4 pairs.
- Median sacral artery (distal branch).
Branches of the celiac trunk
- Left gastric artery.
- Common hepatic artery → proper hepatic artery (right, left branches) + gastroduodenal artery (superior pancreaticoduodenal + right gastroepiploic).
- Splenic artery → branches to the pancreatic tail + short gastric + left gastroepiploic.
Branches of SMA
- Inferior pancreaticoduodenal artery.
- Jejunal and ileal branches.
- Ileocolic artery (a. ileocolica).
- Right colic artery.
- Middle colic artery.
Branches of IMA
- Left colic artery.
- Sigmoid arteries.
- Superior rectal artery.
6. Anastomoses
- Riolan's arch — between the middle and left colic arteries (at the level of the splenic flexure).
- Drummond's marginal artery — along the large intestine.
- Significance: in SMA/IMA occlusion, collaterals through these anastomoses can compensate for blood flow.
- Artery of Adamkiewicz — the main blood supply source for the lower half of the spinal cord.
- Sudeck's point — anastomosis between the superior rectal and sigmoid arteries (risk zone during sigmoid resection).
7. Bifurcation and iliac arteries
- Bifurcation at the L4 level (umbilicus height).
- Common iliac artery → internal iliac + external iliac.
- Internal — pelvis (gluteal, urinary bladder, uterus, rectum).
- External → femoral artery beneath the inguinal ligament.
8. Clinically significant conditions
Aneurysm
- Local dilation > 150% of the normal diameter.
- Abdominal aortic aneurysm (AAA) — > 3 cm; ultrasound screening in men aged 65–75 (smokers).
- Thoracic — > 4.5 cm dilation.
- Intervention indications: AAA ≥ 5.5 cm in men, ≥ 5.0 cm in women, growth > 1 cm/year, symptomatic, ≥ 2× normal diameter.
- EVAR (endovascular) or open surgical repair.
- Rupture risk: at 5 cm — 0.5–5%/year; at 6 cm — 5–10%/year; at 7 cm — > 20%/year.
Aortic dissection
- Type A (Stanford) — involving the ascending aorta → emergency surgery; mortality without surgery 1–2%/hour in the first 24 hours.
- Type B — originates distal to the left subclavian; uncomplicated — medical management (↓ BP, β-blockers), complicated — endovascular (TEVAR).
- Diagnostics — CT angiography.
- Risk factors: hypertension, Marfan/Ehlers-Danlos syndromes, pregnancy, cocaine, aortitis.
Coarctation
- Aortic narrowing in the typical location — the isthmus region (juxtaductal).
- Clinical presentation: hypertension in the upper extremities, weakened pulse in the lower extremities, systolic murmur, rib notching.
- Frequently associated with a bicuspid aortic valve.
- Correction — surgical repair or balloon dilation with/without stenting.
Aortic atherosclerosis
- Plaques in the descending aorta — source of atheroembolism (kidneys, intestines).
- Penetrating atherosclerotic ulcer (PAU) — precursor to dissection.
- Mobile plaques in the arch — risk of acute cerebrovascular accident.
9. Imaging
- Ultrasound — AAA screening.
- CT angiography — method of choice for the entire aorta.
- MR angiography — no radiation exposure, suitable for routine follow-up.
- Transesophageal echocardiography — arch and descending aorta in dissection.
- Aortography — during simultaneous endovascular intervention.
10. FAQ
Why is Type A dissection more dangerous than Type B?
Involvement of the ascending aorta → cardiac tamponade, coronary artery detachment, aortic regurgitation, stroke. Emergency cardiac surgery is the only treatment.
What is Leriche syndrome?
Aortic bifurcation occlusion (often atherosclerotic) with a triad of symptoms: intermittent claudication in both lower extremities, erectile dysfunction, and absent femoral pulses. Revascularization — aortobifemoral bypass or stenting.
Why is the artery of Adamkiewicz important?
It supplies the greater part of the spinal cord below Th8. Its injury during thoracoabdominal aortic surgery leads to paraplegia. Spinal cord perfusion, cerebrospinal fluid drainage, and selective reimplantation reduce the risk.
When should an AAA be operated on?
Diameter ≥ 5.5 cm in men, ≥ 5.0 cm in women; rapid growth > 0.5 cm/6 months or 1 cm/year; symptomatic (back pain, pulsatile mass, emboli); rupture — emergency surgery.
How does EVAR differ from open surgery?
EVAR is endovascular stent-graft placement via the femoral artery; lower early mortality, but higher rate of reinterventions in the long term. Open surgery is indicated for complex anatomy or in young patients.
See also: Aortic aneurysm · Aortic dissection · Coronary arteries · Circle of Willis · Anatomy Catalog