The normal aorta is divided into four parts: the aortic root (aortic annulus, aortic cusps, and aortic sinus), the ascending aorta (sinotubular junction extending to the beginning of the cephalic trunk), the aortic arch (starting at the beginning of the cephalic trunk to the aortic isthmus), and the descending aorta (starting at the isthmus between the left subclavian artery and the arterial ligament, passing anteriorly through the spine and entering the abdominal cavity through the diaphragm).