The forward motion of a car crash causes an inflection point where one half of the aorta moves forward and the other moves backward, which causes the vessel to rip. The inflection points of the aorta are in the descending thoracic aorta at the level of the subclavian artery.
The grade of the transection determines the patient’s prognosis. A full tear is fatal, but in some cases, the tissue around the tear holds it in place, and these patients are seen in the emergency department.