The aorta (aorta) is the largest vessel in the human body. It gives rise to all the arteries of the systemic circulation.

It has the following parts:

The ascending aorta (pars ascendens aortae)

The arch of the aorta (arcus aortae)

The descending aorta (pars descendens aortae)

The aorta arises from the left ventricle (ventriculus sinister). It is located to the left of the middle line of the body and arises from the left ventricle at the level of the third intercostal space.

The descending aorta (pars descendens aortae) is the longest segment of the aorta, which divides into two parts:

The thoracic part (pars thoracica aortae)

The abdominal part (pars abdominalis aortae)

It is located at the level between the fourth thoracic spine and the fourth lumbar spine, where it divides into the right and left common iliac arteries (aortic bifurcation):

The left common iliac artery (a. iliaca communis sinistra)

The right common iliac artery (a. iliaca communis dextra)

These arteries supply the lower limbs and pelvic organs with blood.

The thoracic aorta (pars thoracica aortae) arises from the arch of the aorta and, passing through the diaphragm, continues into the abdominal aorta. It is located in the posterior mediastinum and to the left of the median line.

First it lies anteriorly and slightly to the left of the esophagus, then at the level of the thoracic vertebrae 8 and 9 it circumflexes the esophagus on the left side and goes to its posterior surface. The azygos vein and thoracic duct are located to the right of the thoracic aorta, and the parietal pleura is located to the left. The aorta passes into the abdominal cavity through the aortic hiatus (hiatus aorticus) of the diaphragm.

The thoracic aorta has two groups of branches:

The parietal branches, which supply the walls of the thoracic cavity, the diaphragm, and most of the anterior abdominal wall with blood.

The visceral branches, which supply the thoracic organs with blood.

The parietal branches include:

The superior phrenic artery (a. phrenica superior), which is paired and arises from the aorta above the diaphragm, goes to the lumbar part of the diaphragm of its side and supplies its posterior part with blood.

There are 10 pairs (or 11, according to some sources) of posterior intercostal arteries, which pass in the corresponding intercostal spaces and supply the following structures with blood: muscles and skin of the chest and abdomen, thoracic vertebrae and ribs, the spinal cord and its membranes, and the diaphragm.

It is important to note that the first and second posterior intercostal arteries arise from the superior intercostal artery (branches of the costocervical trunk). And the 3rd-10th (11th) arteries arise directly from the thoracic aorta.

In their course, the posterior intercostal arteries give off several branches:

The collateral branch (r. collateralis) arises from the posterior intercostal artery in the area of the angle of the rib.

The dorsal branch (r. dorsalis) arises from the posterior intercostal artery at the level of the head of the rib. It goes posteriorly to the muscles and skin of the back area, while being accompanied by the dorsal branch of the spinal nerve. Along its course, the dorsal branch of the posterior intercostal artery also gives off several branches of its own:

The medial cutaneous branches (r. cutaneus medialis), which supply the skin of the lateral walls of the thorax with blood

The lateral cutaneous branches (r. cutaneus lateralis), which supply the skin of the lateral walls of the thorax with blood

The spinal branch (r. spinalis) passes through the adjacent intervertebral foramen to the spinal cord, membranes, and roots of spinal nerves.

The branches four to six give off the branches of the mammary gland (rr. mammarii laterales), which supply it with blood.

And the last parietal branches of the thoracic aorta are the subcostal arteries (aa. subcostales). In fact, they are similar to the posterior intercostal arteries, only they are located under the 12th pair of ribs.

The visceral branches of the thoracic aorta include:

The bronchial branches (rr. bronchiales), which arise from the aorta at the level of the thoracic vertebrae 4 and 5 and the left main bronchus. In this case, one right and two left bronchial branches are usually distinguished. They insert into the hila of the lungs and supply the trachea, bronchial tree, and esophagus with blood

The esophageal branches (rr. oesophagei) arise from the aorta at the level of the thoracic vertebrae 4 to 8. They pass to the walls of the thoracic part of the esophagus. The inferior esophageal branches anastomose with the esophageal branches of the left gastric artery (rr. oesophagei a. gastrica sinistra).

The pericardial branches (rr. pericardiaci) arise from the aorta behind the pericardium and pass to the posterior part of the pericardium. They supply the pericardium, lymph nodes and the connective tissue of the posterior mediastinum.

The mediastinal branches (rr. mediastinales) arise from the thoracic aorta in the posterior mediastinum. They supply the fatty tissue and lymph nodes of the posterior mediastinum.

Anastomoses:

The bronchial branches (rr. bronchiales) anastomose with the branches of the pulmonary artery (a. pulmonalis).

The spinal branches (r. spinalis) anastomose in the spinal canal with the branches of the same name on the opposite side, and with the spinal branches of the vertebral (a. vertebralis), ascending cervical (a. cervicalis ascendens) and lumbar arteries (a. lumbales).

The posterior intercostal arteries 1 to 8 anastomose with the anterior intercostal branches (rr. intercostales anteriores) of the internal thoracic artery (a. thoracica interna)

The posterior intercostal arteries 9 to 11 (aa. intercostales posteriores) anastomose with the branches of the superior epigastric artery (a. epigastrica superior) of the internal thoracic artery (a. thoracica interna).

Dictionary

Thoracic aorta and its branches

Thoracic aorta

pars thoracica aortae

Diaphragm

diaphragma

Aortic hiatus

hiatus aorticus

Posterior intercostalarteries

aa. intercostales posteriores

Posterior branch

r. dorsalis

Medial and lateral cutaneus branch

rr. cutanei medialis et lateralis

Spinal branches

r. spinalis

Lateral mammary branches

rr. mammarii laterales

Superior phrenic artery

a. phrenica superior

Bronchial branches

rr. bronchiales

Esophageal branches

rr. oesophagei

Left gastric artery

a. gastrica sinistra

Pericardial branches

rr. pericardiaci

Mediastinal branches

rr. mediastinales

Vertebral artery

a. vertebralis

Ascending cervical artery

a. cervicalis ascendens

Lumbar arteries

aa. lumbales

Anterior intercostal branches

rr. intercostales anteriores

Internal thoracic artery

a. thoracica interna

Superior epigastric artery

a. epigastrica superior