abdominal aorta Abdominal part of aorta: the distal part of the descending aorta, which is the continuation of the thoracic part and gives rise to the inferior phrenic, lumbar, median sacral, superior and inferior mesenteric, middle suprarenal, renal, and testicular or ovarian arteries, and celiac trunk[BTO]. The abdominal aorta is the largest artery in the abdominal cavity. As part of the aorta, it is a direct continuation of descending aorta(of the thorax). [WP,unvetted]. abdominal aorta segment of aorta