The aorta arises out of the heart and forms an arch. Before descending in the chest as the thoracic aorta, it sends arteries into the head and arms. The thoracic aorta travels through the diaphragm and becomes the abdominal aorta, where many branches take off to supply the internal organs. It eventually branches into the iliac arteries and supplies blood down into the legs.
Veins of the Torso
The inferior vena cava collects the blood returning from the lower extremity and the abdominal cavity. It ascends along the spinal column into the thoracic cavity and meets the superior vena cava, where it drains into the heart’s right atrium.
The circulatory system carries blood to all parts of the body, and the one-way flow of blood within the body is called circulation. Arteries (carrying oxygen-rich blood) transport blood away from the heart. Veins (carrying oxygen-poor blood) transport blood back to the heart.
Texas Heart Institute www.texasheartinstitute.com/HIC/Anatomy/torso.cfm