anatomy Anatomy () is the branch of morphology concerned with the study of the internal structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old scien ...

, the ''venae cavae'' (; ''vena cava'' ; ) are two large

vein Veins () are blood vessels in the circulatory system of humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are those of the pulmonary and feta ...

s (

great vessels Great vessels are the large vessels that bring blood to and from the heart. These are: * Superior vena cava * Inferior vena cava * Pulmonary arteries * Pulmonary veins * Aorta Transposition of the great vessels is a group of congenital A b ...

) that return deoxygenated

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood is com ...

from the body into the

heart The heart is a muscular Organ (biology), organ found in humans and other animals. This organ pumps blood through the blood vessels. The heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrie ...

. In humans they are the

superior vena cava The superior vena cava (SVC) is the superior of the two venae cavae, the great venous trunks that return deoxygenated blood from the systemic circulation to the right atrium of the heart. It is a large-diameter (24 mm) short length vei ...

and the

inferior vena cava The inferior vena cava is a large vein that carries the deoxygenated blood from the lower and middle body into the right atrium of the heart. It is formed by the joining of the right and the left common iliac veins, usually at the level of the ...

, and both empty into the

right atrium The atrium (; : atria) is one of the two upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the heart ventricles through the atrioventricular mitral and tricuspid heart valves. ...

. They are located slightly off-center, toward the right side of the body. The right atrium receives deoxygenated blood through

coronary sinus The coronary sinus () is the largest vein of the heart. It drains over half of the deoxygenated blood from the heart muscle into the right atrium. It begins on the backside of the heart, in between the left atrium, and left ventricle; it begi ...

and two large veins called venae cavae. The inferior vena cava (or caudal vena cava in some animals) travels up alongside the

abdominal aorta In human anatomy, the abdominal aorta is the largest artery in the abdominal cavity. As part of the aorta, it is a direct continuation of the descending aorta (of the thorax). Structure The abdominal aorta begins at the level of the diaphragm ...

with blood from the lower part of the body. It is the largest vein in the human body."What is the largest vein in the human body?"
MadSci Network: Anatomy. Retrieved 19 September 2013. The superior vena cava (or cranial vena cava in animals) is above the heart, and forms from a convergence of the left and right

brachiocephalic vein The left and right brachiocephalic veins (previously called innominate veins) are major veins in the Thorax, upper chest, formed by the union of the ipsilateral internal jugular vein and subclavian vein (the so-called venous angle) behind the ster ...

s, which contain blood from the head and the arms.

References

{{Authority control Veins