Parts of the aorta
Aorta (aorta) is the largest arterial vessel originating from the left ventricle of the heart. Topographically, several consecutive parts are distinguished:
- Ascending aorta (pars ascendens aortae) — runs superiorly from the ostium of the left ventricle;
- Aortic arch (arcus aortae) — arches to the left and posteriorly at the level of the 2nd rib (an important auscultatory landmark in propedeutics);
- Descending aorta (pars descendens aortae) — is divided into the thoracic and abdominal parts;
- Thoracic aorta (pars thoracica) — is located above the diaphragm;
- Abdominal aorta (pars abdominalis) — continues below the aortic hiatus of the diaphragm and divides at the level of the 4th lumbar vertebra into the right and left common iliac arteries.
Branches of the ascending aorta: coronary arteries
Two coronary arteries arise from the ascending aorta, supplying the myocardium.
- Right coronary artery (a. coronaria dextra) gives off the marginal branch (r. marginalis) and the posterior interventricular artery (r. interventricularis posterior), which supplies the posterior part of the interventricular septum;
- Left coronary artery (a. coronaria sinistra) divides into the anterior interventricular branch (r. interventricularis anterior) and the circumflex branch (r. circumflexus), which wraps around the left myocardium.
The anterior and posterior interventricular branches anastomose with each other in the region of the apex of the heart.
Branches of the aortic arch
Three major trunks supplying the head, neck, and upper limbs arise sequentially from the aortic arch:
- Brachiocephalic trunk (truncus brachiocephalicus) — divides into the right common carotid artery (a. carotis communis dextra) and the right subclavian artery (a. subclavia dextra);
- Left common carotid artery (a. carotis communis sinistra) — arises directly from the arch;
- Left subclavian artery (a. subclavia sinistra).
Each common carotid artery subsequently divides into the external and internal carotid arteries.
Thoracic aorta
The branches of the thoracic aorta are divided into visceral (to organs) and parietal (to cavity walls).
Visceral branches:
- Bronchial branches (rr. bronchiales) — to the bronchi and lung tissue;
- Pericardial branches (rr. pericardiaci) — to the pericardium;
- Esophageal branches (rr. oesophageales) — to the wall of the esophagus.
Parietal branches:
- Posterior intercostal arteries (aa. intercostales posteriores) — correspond to the intercostal spaces;
- Superior phrenic arteries (aa. phrenicae superiores) — to the upper surface of the diaphragm.
Abdominal aorta: unpaired visceral branches
The abdominal aorta gives off three major unpaired trunks supplying the digestive system.
Celiac trunk (truncus coeliacus) divides into three arteries:
- Left gastric artery (a. gastrica sinistra);
- Splenic artery (a. lienalis) — characterized by a tortuous course;
- Common hepatic artery (a. hepatica communis).
Superior mesenteric artery (a. mesenterica superior) supplies the pancreas, small intestine, and the right half of the colon. Its branches are:
- inferior pancreaticoduodenal artery;
- jejunal and ileal arteries (aa. jejunales et ileales), forming vascular arcades;
- ileocolic artery (a. ileocolica) with a branch to the vermiform appendix;
- right colic artery (a. colica dextra);
- middle colic artery (a. colica media).
Inferior mesenteric artery (a. mesenterica inferior) supplies the left half of the colon:
- left colic artery (a. colica sinistra);
- sigmoid arteries (aa. sigmoideae);
- superior rectal artery (a. rectalis superior).
Paired branches and parietal vessels of the abdominal aorta
In addition to the unpaired visceral branches, paired vessels to the retroperitoneal organs arise from the abdominal aorta:
- Renal arteries (aa. renales) — to the kidneys;
- Suprarenal arteries: superior (from the inferior phrenic artery), middle (directly from the aorta), inferior (from the renal artery);
- Testicular/ovarian arteries (aa. testiculares/ovaricae) — descend to the gonads;
- Inferior phrenic arteries (aa. phrenicae inferiores);
- Lumbar arteries (aa. lumbales) — to the muscles of the lower back and back.
At the level of the 4th lumbar vertebra, the abdominal aorta divides into the right and left common iliac arteries (aa. iliacae communes), supplying the pelvis and lower limbs. At the bifurcation site, the unpaired median sacral artery (a. sacralis mediana) arises, supplying the sacrum and coccyx.
Key points
- The aorta is divided into the ascending part, arch, thoracic, and abdominal descending parts; the arch projects at the level of the 2nd rib.
- The ascending aorta gives off the right and left coronary arteries to supply the myocardium.
- Three trunks arise from the aortic arch: the brachiocephalic, left common carotid, and left subclavian arteries.
- The thoracic aorta gives off visceral branches (bronchial, pericardial, esophageal) and parietal branches (posterior intercostal, superior phrenic).
- The celiac trunk divides into the left gastric, splenic, and common hepatic arteries.
- The superior and inferior mesenteric arteries divide the blood supply zones of the colon along Griffith's point at the left colic flexure.
- The adrenal gland has a triple arterial blood supply from three different sources.
- The bifurcation of the abdominal aorta occurs at the level of L4, giving rise to the common iliac arteries and the median sacral artery.