aorta /ā·ôr″tə/ [Gk, aerein, to raise] , the main trunk of the systemic arterial circulation, comprising four parts: the ascending aorta, the arch of the aorta, the thoracic portion of the descending aorta, and the abdominal portion of the descending aorta. It starts at the aortic opening of the left ventricle, rises a short distance, bends over the root of the left lung, descends within the thorax on the left side of the vertebral column, and passes through the aortic hiatus of the diaphragm into the abdominal cavity. It branches into the two common iliac arteries. −aortic, adj.
