Aorta

The aorta (aorta) is the largest unpaired arterial vessel of the great circle of blood circulation. The aorta is divided into three sections: the ascending part of the aorta, the arch of the aorta and the descending part of the aorta, which in turn is divided into the thoracic and abdominal parts).

The ascending part of the aorta (pars ascendens aortae) emerges from the left ventricle behind the left edge of the sternum at the level of the third intercostal space. In the initial section, it has an extension - the bulb of the aorta (bulbus aortae, 25-30 mm across). At the location of the aortic valve, on the inner side of the aorta there are three sinuses (sinus aortae). Each of them is located between the corresponding semilunar flap and the wall of the aorta. From the beginning of the ascending part of the aorta, the right and left coronary arteries depart . The ascending part of the aorta lies behind and partly to the right of the pulmonary trunk, rises and at the level of the cartilage connection II of the right rib with the sternum passes into the arch of the aorta (here its diameter is 21-22 mm).

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The branches of the aorta

Branches of the ascending aorta

1. Venous arteries

Aortic arch branches

1. Brachiocephalic trunk
2. Left common carotid artery
3. Left subclavian artery

The branches of the descending part of the aorta

1. The thoracic part of the aorta
   • Bronchial branches
   • Mediastinal branches
   • Esophageal branches
   • Upper diaphragmatic arteries
   • Pericardial branches
   • Posterior intercostal arteries
2. Abdominal part of the aorta
   • Unpaired branches
     • The celiac trunk
     • Upper mesenteric
     • Lower mesenteric
     • The median sacral
   • Twin branches
     • Lower diaphragmatic arteries
     • Middle adrenal artery artery
     • Renal arteries
     • Ovarian (ovarian) artery artery
     • Lumbar arteries
     • Common iliac artery arteries

The arc of the aorta (arcus aortae) turns left and back from the posterior surface of cartilage II of the rib to the left side of the IV body of the thoracic vertebra, where it passes into the descending part of the aorta. In this place there is a slight narrowing - the isthmus of the aorta (isthmus aortae). The edges of the corresponding pleural sacks fit the anterior anterior half of the aorta from the right and left sides of the aorta. To the convex side of the arch of the aorta and to the initial sections of the large vessels that extend from it (the brachiocephalic trunk, the left common carotid and subclavian arteries), the left brachiocephalic vein comes in front , and the right pulmonary artery begins beneath the aortic arch , and a bifurcation of the pulmonary trunk is located below and slightly to the left . Behind the arch of the aorta is a bifurcation of the trachea. Between the concave semicircle of the aortic arch and the pulmonary trunk or the beginning of the left pulmonary artery there is an arterial ligament (lig.arteriosum). In this place, from the arch of the aorta, thin arteries extend to the trachea and bronchi. From the convex semicircle of the arch of the aorta, three large arteries begin: the brachiocephalic trunk, the left common carotid and the left subclavian.

The descending part of the aorta (pars descendes aortae) is the longest section of the aorta, extending from the level IV of the thoracic vertebra to the IV lumbar region, where it divides into the right and left iliac arteries; this place is called bifurcation of the aorta (bifurcatio aortae). In the descending part of the aorta, in turn, the thoracic and abdominal parts are distinguished.

The thoracic part of the aorta (pars thoracica aortae) is located in the thoracic cavity, in the posterior mediastinum. The upper part of it is located in front and to the left of the esophagus. Then, at the level of VIII-IX of the thoracic vertebrae, the aorta passes around the esophagus to the left and leaves on its posterior surface. To the right of the thoracic part of the aorta there is an unpaired vein and thoracic duct, on the left side there is a parietal pleura at the site of its passage into the posterior part of the left mediastinal pleura. In the thoracic cavity the thoracic part of the aorta gives the pair parietal branches - the posterior intercostal arteries, as well as the visceral branches to the organs of the posterior mediastinum.

The abdominal part of the aorta (pars abdominalis aortae), as a continuation of the thoracic part of the aorta, begins at the level of the XII thoracic vertebra, passes through the aortic opening of the diaphragm and continues to the level of the middle of the body of the IV lumbar vertebra. The abdominal part of the aorta is located on the front surface of the body of the lumbar vertebrae, to the left of the median line, lies retroperitively. To the right of the abdominal part of the aorta are the lower hollow vein, anterior to the pancreas, the horizontal (lower) part of the duodenum, and the root of the mesentery of the small intestine. The abdominal aortic (vegetative) plexus, the nodes of the celiac, aortic and interbridge plexuses are located on the aorta. The abdominal part of the aorta gives the paired parietal branches to the diaphragm and the walls of the abdominal cavity, and the aorta itself directly extends into the thin median sacral artery. Visceral branches of the abdominal part of the aorta are the celiac trunk, upper and lower mesenteric arteries (unpaired branches) and paired - renal, middle adrenal, testicular (ovarian) arteries.