<P> It is formed by the left and right brachiocephalic veins (also referred to as the innominate veins), which also receive blood from the upper limbs, eyes and neck, behind the lower border of the first right costal cartilage . It passes vertically downwards behind first intercostal space and receives azygos vein just before it pierces the fibrous pericardium opposite right second costal cartilage and its lower part is intrapericardial . And then, it ends in the upper and posterior part of the sinus venarum of the right atrium, at the upper right front portion of the heart . It is also known as the cranial vena cava in other animals . </P> <P> No valve divides the superior vena cava from the right atrium . As a result, the (right) atrial and (right) ventricular contractions are conducted up into the internal jugular vein and, through the sternocleidomastoid muscle, can be seen as the jugular venous pressure . </P> <P> Superior vena cava obstruction refers to a partial or complete obstruction of the superior vena cava, typically in the context of cancer such as a cancer of the lung, metastatic cancer, or lymphoma . Obstruction can lead to enlarged veins in the head and neck, and may also cause breathlessness, cough, chest pain, and difficulty swallowing . Pemberton's sign may be positive . Tumours causing obstruction may be treated with chemotherapy and / or radiotherapy to reduce their effects, and corticosteroids may also be given . </P> <P> In tricuspid valve regurgitation, these pulsations are very strong . </P>

Is blood in the superior vena cava oxygenated