Final answer:
The motion of a congenitally stenotic aortic valve on a 2D Echocardiogram is best described as doming, where the rigid valve leaflets exhibit a restricted opening pattern.
Step-by-step explanation:
On a 2D Echocardiogram, the motion of a congenitally stenotic aortic valve can generally be described as doming. Aortic stenosis is characterized by the valves becoming rigid and sometimes calcifying over time. This loss of flexibility leads to a restricted opening motion during the heart's systole phase, causing the valve leaflets to dome upwards in a restricted manner rather than opening fully. The term 'doming' captures this abnormal motion pattern, which is distinct from prolapse, where valve cusps are forced backward, or fluttering, where the valves exhibit a rapid motion due to interference with regular blood flow.