Superior vena cava

 

  • Formed by two large tributaries- the right and left brachiocephalic veins

  • Each brachiocephalic vein is formed in turn by two large tributaries, the subclavian vein bringing blood from the upper limb

  • The internal jugular drains the head and neck.

  • In addition to these veins the superior vena cava receives azygous vein draining the thoracic and upper abdominal walls.

  • Thus the superior vena cava is the great channel draining blood from the head and neck both upper limbs, thoracic wall and the upper part of the abdominal wall.

  • Formed at the lower border of the 1st costal cartilage

  • Ends opposite the 3rd costal cartilage by entering the right atrium

  • Upper half lies in the superior mediastinum and lower half which is intrapericardial in the middle mediastinum
  • It is devoid of valves

Relations
Left

  • Overlapped anteriorly by the ascending aorta
  • Beginning of aortic arch

Right

  • Right pleura
  • Right phrenic nerve

Posterior

  • Trachea
  • Right vagus
  • Root of right lung

Tributaries

    • Two brachiocephalic trunk
    • Azygous vein