Veins Of the Thoracic Cavity

The thoracic cavity is the region from where all blood vessels originate and terminate. Following are some of the blood vessels of the thoracic cavity carrying deoxygenated blood.

Veins of the Thoracic Cavity

• Brachiocephalic Vein

The brachiocephalic veins are vessels of mediastinum that carries deoxygenated blood from the superior portion of the human body ( arms, neck, and head ) to the right atrium. The right brachiocephalic vein is formed by the union of the right internal jugular veins and right subclavian artery, at the root of the neck. The left brachiocephalic vein has also the same origin, it descends to the right behind the manubrium sterni and in front of the large branches of the aortic arch. The right and left brachiocephalic vein combine to form superior vena cava.

• Superior Vena Cava

The superior vena cava drains all the venous blood from the head and neck both upper limbs and passes downward to end in the right atrium of the heart. It is formed by the union of the right and left brachiocephalic vein. The azygous vein joins the posterior aspect of the superior vena cava.

• Azygos Veins

The azygos veins collect blood from the posterior abdominal wall, posterior intercostal spaces, the pericardium, the bronchi, the esophagus and the diaphragm. They are consist of the main azygos vein, the inferior azygos vein, and the superior azygos vein. 

1. Azygos vein: The main azygos vein is formed by the union of the right ascending lumbar vein and the right subcostal vein, at the fifth thoracic vertebrae it arches forward to empty into the posterior surface of the superior vena cava. Its tributaries are mediastinal veins, eight lower right intercostal veins, the right superior intercostal vein, and the superior and inferior hemiazygos veins.
2. Superior hemiazygos vein: It is formed by the union of the fourth to the eighth intercostal veins, at 7th T vertebrae it joins the azygos vein.
3. Inferior hemiazygos vein: The inferior hemiazygos vein is formed by the union of the left ascending lumbar vein and the left subcostal vein. Its tributaries are lower left intercostal veins and mediastinal veins.

• Inferior vena cava

The inferior vena cava resources blood from the inferior segment of the human body, it enters mediastinum via the central tendon of the diaphragm, at the level of the eighth thoracic vertebrae and enters the bottom part of the right atrium.