The abdominal aorta is a long tube with many branches that taper down from the diaphragm toward the pelvis until it forks off into the two iliac arteries, describes InnerBody. It is the largest artery of the human body, states MedicineNet.
The abdominal aorta consists of a large blood vessel about an inch in diameter that runs from the diaphragm to the pelvis, just forward of the spine, notes InnerBody. It branches as it travels, forming the major arteries that feed the organs of the abdomen and pelvis. As it branches, it tapers before forking into a Y shape.
The aorta originates from the left ventricle of the heart, and it seamlessly divides into the iliac arteries at an arbitrary point, explains MedicineNet. Although there is no formal endpoint to the aorta, it branches into the iliac arteries well before it extends into the thighs.