Human Anatomy: Part 2 - K. A. Dyubenko, A. K. Kolomiytsev, Yu. B. Chaykovsky 2008

Special Part
Cardiovascular System, systema cardiovasculare — Special Part
Blood Vessels of the Systemic Circulation — Thoracic Aorta and Its Branches

The Thoracic Aorta, pars thoracica aortae (see Figs. 21, 41), is the descending part of the aorta, running within the posterior Mediastinum directly along THE Vertebral Column. To the right, the thoracic aorta is bordered by the Thoracic duct, ductus thoracicus, and the azygos vein, v.azygos; to the left, by the hemiazygos vein, v.hemiazygos; and anteriorly, by the left principal bronchus, bronchus principalis sinister. The Esophagus changes its position relative to the aorta along its course: its upper third lies to the right of the aorta, the middle third anteriorly, and the lower third to the left. The thoracic aorta gives rise to visceral and parietal branches that supply Blood to the Organs of the posterior mediastinum and the walls of the thoracic cavity.

Visceral branches:

1. Rr.bronchiales;

2. Rr.oesophageae;

3. Rr.pericardiales;

4. Rr.mediastinales.

The bronchial branches, rr.bronchiales (Fig. 21 A), are 2-3 branches arising from the anterior surface of the aorta and running toward the Trachea and Bronchi. They enter the hila of the right and left Lungs, accompany the bronchi, and form the intra-organ bronchial arterial network. The bronchial branches supply the walls of the bronchi, lungs, and Lymph Nodes. Within the lungs, these branches anastomose with the Branches of the pulmonary Arteries.

The esophageal branches, rr. oesophageae (Fig. 21 A), are 4-5 branches originating from the aorta at the level of Th IV - Th VIII and directed toward the esophageal walls. The esophageal branches anastomose with branches of the superior and inferior thyroid arteries and the superior phrenic arteries.

The pericardial branches, rr.pericardiaci, are 1-2 short branches originating from the anterior surface of the aorta that supply the posterior wall of the Pericardium.

The mediastinal branches, rr.mediastinales, supply the adipose tissue and lymph nodes of the posterior mediastinum.

Parietal branches:

1. Aa.phrenicae superiores;

2. Aa.intercostales posteriores.

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Fig. 41. Thoracic aorta, pars thoracica aortae (anterior view) (after R. D. Sinelnikov)

The superior phrenic arteries, aa.phrenicae superiores, originate from the aorta above the hiatus aorticus and supply the lumbar part of the Diaphragm.

The posterior intercostal arteries, aa.intercostales posteriores (Figs. 21, 21 A), numbering 9-10 pairs, arise from the posterior wall of the aorta and course through the III–XI intercostal spaces to supply the intercostal Muscles, Skin, and Ribs*. The last posterior subcostal artery, a.subcostalis, runs inferior to the XII rib. Near the heads of the ribs, the intercostal arteries give off dorsal branches, rr.spinalis, which supply the skin, back muscles, vertebral column, Spinal Cord, and its Meninges. Near the angles of the ribs, the arteries penetrate between the external and internal muscles, resting within the costal groove. The upper posterior intercostal arteries (I-IV) anastomose with the anterior intercostal branches, aa.intercostales anteriores, from the internal thoracic artery. They supply the chest wall, whereas the lower three (IX-XI) supply the anterior abdominal wall and diaphragm, anastomosing with branches of the superior epigastric artery, a.epigastrica superior.