There are two brachiocephalic veins that are located immediately posterior to the thymus. Each of these veins are formed by the union of the internal jugular (read more!) and subclavian veins (read more!). Both brachiocephalic veins merge and form the superior vena cava (read more!).

Right brachiocephalic vein

The right brachiocephalic vein begins behind the medial end of the right clavicle and descends vertically. It unites with the left brachiocephalic vein and forms the superior vena cava.

The major venous tributaries of the right brachiocephalic vein are:

• Vertebral vein
• Right supreme posterior intercostal vein
• Internal thoracic veins

It may also receive the inferior thyroid and thymic veins.

Left brachiocephalic vein

The left brachiocephalic vein begins behind the medial end of the left clavicle and passes to the right, moving in a slightly inferior direction. Then it crosses the midline behind the manubrium of the sternum in the adult and joins with the right brachiocephalic vein to form the superior vena cava. The superior vena cava is formed posterior to the lower edge of the first costal cartilage close to the right sternal border.

The main tributaries of the left brachiocephalic vein include the following:

• Vertebral vein
• Left supreme posterior intercostal vein
• Left superior intercostal vein
• Inferior thyroid vein
• Internal thoracic veins

It may also receive thymic and pericardial veins.